Interactions between woodlice and millipedes for leaf...

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Faculty of Sciences Department of Biology

Terrestrial Ecology Unit

Academic year 2015 – 2016

Interactions between woodlice and millipedes for

leaf litter breakdown under changing

environmental conditions.

Tom Van de Weghe

Supervisor: Prof. dr. Dries Bonte

Co-supervisor: Prof. dr. ir. Kris Verheyen

Tutor: ir. Pallieter De Smedt

Thesis submitted to obtain the degree of

Master of Science in Biology

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2016 Faculty of Sciences – Terrestrial Ecology Unit

© Deze masterproef bevat vertrouwelijke informatie en vertrouwelijke

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© All rights reserved. This thesis contains confidential information and confidential

research results that are property to the UGent. The contents of this master thesis may

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1. introduction 1

1.1 Macro-arthropod behavior 1

1.2 Soil biota diversity 2

1.3 Litter quality 3

1.4 General trends 4

2. Objectives 5

3. Materials and Methods 6

3.1 Study area 6

3.2 Experimental setup 6

3.2.1 Microcosms 6

3.2.2 Soil fauna 8

3.2.3 Leaf litter 9

3.2.4 Moisture and temperature manipulation 10

3.3 Statistical analysis 11

4. Results 12

4.1 Manipulation of environmental conditions 12

4.1.1 Rainfall 12

4.1.2 Soil Moisture 13

4.1.3 Temperature 14

4.2 Leaf litter decomposition 15

4.2.1 High quality litter decomposition 15

4.2.2 Low quality litter decomposition 18

4.3 Macro-detritivore weight differences 21

4.4 Macro-detritivore survival rate 22

5. Discussion 25

5.1 Environmental treatment effectiveness 25

5.2 Leaf litter decomposition by soil fauna 25

5.3 Environmental effects on soil fauna effectiveness 26

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5.4 Shift in litter preference under different environmental conditions 27

5.5 Macro-detritivore survival 28

5.6 Notes on future research 28

6. Conclusion 29

7. Summary 30

8. Samenvatting 33

9. Acknowledgements 36

10. References 37

11. Addendum 41

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1. Introduction

Europe’s history has been one of deforestation due to clearing ground for grazing and

burnings to accommodate the changing forms of agriculture. Although recent years have

seen a wave of reforestation, few forests remain without anthropogenic influences

(Bradshaw 2004). Fragmentation poses a great threat to Europe’s forests, changes in

moisture conditions can already be seen at the edge of fragmented forests. Due to higher

exposure to wind and sunlight, forest edges suffer from lower water availability compared to

the interior. These conditions could be strengthened by climate change, with IPCC reports

showing an increase in temperature up to a maximum of 4°C for the next century and

precipitation patterns changing to longer drought periods followed by heavier rains (Boer et

al. 2000; IPCC 2007). These could potentially extend these edge effects deeper into the

forest (Billings & Gaydess 2008; Riutta et al. 2012; Bogyó et al. 2015). Elevated air

temperatures result in higher saturation deficits, which increase evapotranspiration and

make regional climates increasingly dependent on rainfall (Begon et al. 2006). The effect of

drought stress can already be observed in some forest sites in Hess, Germany, where native

tree species such as Quercus robur L. show strong water-deficit damage (Gerlach et al. 2014).

As more severe summer droughts become more likely (IPCC 2007), this may have

demographic consequences for animals as well.

1.1 Macro-arthropod behavior

Macro-arthropods cope with normal seasonal droughts using both behavioral and

physiological mechanisms. Woodlice and millipedes contribute greatly to the biodiversity of

this group and are key regulators of plant litter decomposition. Basic behavior is to burrow

into the soil or to take refuge in cavities or fallen deadwood (Topp et al. 2006; David &

Handa 2010). The ability to burrow varies among species and generally millipedes burrow

deeper in the soil than woodlice (Davis et al. 1977). Physiological adaptations such as a

reduced metabolism and water vapor absorption in unsaturated air allow millipedes to

survive long periods of time in unfavorable conditions (Wright & Westh 2006) albeit paired

with lower growth rates (David 2009). This may indicate that lower levels of litter

decomposition by millipedes may be the result of reduced activity instead of higher

mortality resulting in smaller populations. Despite these adaptations, species of millipedes

with a lesser adaptation to drought (such as the order Chordeumatida) suffered significant

population declines after an exceptionally long drought (David 1990). Unlike many millipede

species that stay inactive for long periods during the dry season, woodlice emerge from their

retreats to forage at the most favorable times of the day (Shachak et al. 1979). Woodlice

generally show less adaptation to drought compared to millipedes, showing a consistent

decrease in growth and increase in mortality for a 20% decrease in relative humidity (Dixie et

al. 2015), with juveniles being particularly sensitive to unfavorable environmental conditions

(Zimmer 2005).

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In contrast to the effects of low moisture, studies suggest that higher temperatures cause

positive physiological responses in woodlice and millipedes when moisture is non-limiting

(David & Handa 2010; Dixie et al. 2015). Higher temperatures result in earlier reproduction

in spring, along with the production of larger offspring, positive effects on survival and

stress, individual growth and higher fecundity for non-diapausing species (Hassall et al.

2005). Species that diapause in winter and therefore need a period of chilling to resume

development and reproduction would still be negatively influenced by a rise in temperature.

Overwintering species may experience an acceleration of metabolic rates that would exhaust

their reserves (Hassall et al. 2005). Species that are currently living at their upper thermal

limits and are unable to shift their range are potentially threatened (Parmesan 2006).

1.2 Soil biota diversity

When elaborating on the effect of soil biota assemblages on litter decomposition rates there

are two main views. Firstly, that changes in the diversity of detritivore fauna may not have a

predictable effect on litter decomposition rates and that the functioning of the microbial-

feeding trophic group is influenced mainly by the functional attributes of the dominant

detritivore species (Cragg & Bardgett 2001; Bílá et al. 2014). And secondly, that an increase

in detritivore fauna diversity increases the nutrient mineralization and species with similar

functional traits are not functionally redundant but act synergistically on litter

decomposition (Bardgett & Chan 1999). These two seemingly contradictory views imply that

the effects of detritivore diversity on ecosystem processes are context-specific and depend

largely on species-specific characteristics of the detritivores (Zimmer et al. 2005).

Litter decomposition is significantly slower at the forest edge due to a dryer regime (Riutta

et al. 2012). The role of macro-invertebrates in this is unclear, with results from different

studies varying from a 1,6% to 66% increase in litter decomposition depending on liter type

and moisture/temperature regimes compared to situations without macro-invertebrates

present (Vasconcelos & Laurance 2005; Gonzalez & Seastedt 2001). And although soil biota

has shown a strong sensitivity to drought, some studies have shown that they remained

unaffected (Taylor et al. 2004; Staley et al. 2007). Their resistance is most likely due to

differences among species (Riutta et al. 2012). Thus, if conditions continue to become drier

or droughts become more common, functioning of the macro-invertebrates may be

reduced, and a shift in community composition towards species that are more adapted to

low moisture levels may occur (Collison et al. 2013).

However, in urban environments, such as parks or along roadways, the presence of soil

macro-invertebrates shows a clear and better exploitation of ecosystem resources (Pieper &

Weigmann 2008). Interaction between species with different functional traits become more

important in more inhospitable habitats (Zimmer et al. 2005). This suggests that the effects

of soil macro-invertebrates on leaf litter decomposition are likely to be driven by

complementarity between different species, or the facilitation of the microorganisms on

which they feed (Heemsbergen et al. 2004; Hedde et al. 2010). Although the macro-

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detritivores feed on the microorganisms that live on dead organic matter as well, they also

provide more suitable environments for these microorganisms (Anderson & Bignell 1980;

Ihnen & Zimmer 2008). Soil macro-fauna comminutes coarse litter, increasing the surface

area and therefore making the substrate more accessible for smaller organisms. As such,

their faeces serve as hotspots of digested organic material with highly available nutrients for

microbial use (Hassall et al. 1987; Rawlins et al. 2006; Ihnen & Zimmer 2008; Pieper &

Weigmann 2008; Vos et al. 2011; Gerlach et al. 2014).

1.3 Litter quality

Apart from soil moisture and rainfall, litter quality also greatly influences litter

decomposition by macro-invertebrates (Szanser et al. 2011; Slade & Riutta 2012). The

general opinion that macro-invertebrates are in rule generalists may not be true, it has been

demonstrated that many soil-invertebrates may show food specialization and preference

(Szanser et al. 2011). Litter types are generally classified as high or low quality, with high

quality litter having a lower lignin concentration and lower C/N ratio than low quality litter.

Examples of tree species with low quality litter in temperate Europe are Quercus robur L.,

Quercus ilex L., Fagus sylvatica L., Betula pubescens Ehrh., high quality litter are Fraxinus

excelsior L., Alnus glutinosa (L.) Gaertn., Alnus incana (L.) Moench (Zimmer et al. 2005; van

Geffen et al. 2011; Collison et al. 2013).

Generally, studies show that litter breakdown by macro-invertebrates is faster in high quality

litter with a lower C/N ratio and lignin concentration, with an increase of up to 30%

compared to litter breakdown without macro-invertebrates present (Zimmer et al. 2005;

Snyder et al. 2009; Meyer et al. 2011; Szanser et al. 2011; van Geffen et al. 2011; Collison et

al. 2013). Besides litter quality, litter species diversity also affects litter decomposition.

When researching if humification processes are affected by micro-invertebrate nematode

populations, nutrient release was found to be higher under mixtures than under single-

species litter treatments. With nitrogen and carbon content released from the litter

respectively 2,7 and 1,4 times higher in mixed litter (Szanser et al. 2011). This indicates that

the decomposition of diverse litter leads to a higher accumulation of humus in the substrate

compared to humification of single species litter (Szanser et al. 2011; Slade & Riutta 2012).

Monosaccharide and protein concentrations were considerably lower in macro-invertebrate

faeces compared to concentrations in leaf litter. This would indicate assimilation of these

elements in macro-invertebrate bodies. Vanillyl and syringyl units, used to describe microbial

alteration of lignin, were found in higher concentrations in macro-invertebrate faeces,

indicating a change of lignin functionalities in the invertebrate gut by microbial activity

(Rawlins et al. 2006). However, data variability explained by C/N ratio or lignin content are in

most cases smaller than the unexplained variability. This indicates other factors responsible

for litter palpability such as microbial colonization or activity on the litter (Ihnen & Zimmer

2008; Gerlach et al. 2014). Microbial colonization increased the attractiveness of a given

food source, particularly when the food source is of low quality (Ihnen & Zimmer 2008).

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1.4 General trends

Field experiments on litter decomposition by macro-arthropods have been conducted in the

past, generally using litter bags (Irmler 2000; Meyer et al. 2011; Riutta et al. 2012). But the

majority of research on this subject is done through laboratory experiments using

microcosms. These are placed in climate controlled laboratory environments with controlled

litter and macro-invertebrate compositions to test the invertebrates’ influence over a certain

time period (Bardgett & Chan 1999; Cragg & Bardgett 2001; David & Gillon 2002; Zimmer et

al. 2005; Rawlins et al. 2006; Pieper & Weigmann 2008; Snyder et al. 2009; Hedde et al.

2010; van Geffen et al. 2011; Vos et al. 2011; Collison et al. 2013; Bílá et al. 2014; Gerlach et

al. 2014; Dixie et al. 2015). Microcosms have been used in field experiments with varying

litter compositions (Szanser et al. 2011). However, very little field work has been done with

varying macro-invertebrate populations and where environmental conditions are influenced.

Although some experiments incorporate a follow-up of the rate of decomposition through

time (Cragg & Bardgett 2001; Szanser et al. 2011; Collison et al. 2013), the majority of

experiments run for single fixed time period (Irmler 2000; Hedde et al. 2010; Meyer et al.

2011; van Geffen et al. 2011; Vos et al. 2011; Riutta et al. 2012). In this experiment we

concentrated on these two points: to study the effect of set populations of macro-

invertebrates on the decomposition of presented litter in a semi-natural environment and to

follow these effects through time. Manipulation of the natural environment is done to

simulate environmental conditions predicted by climate change models, and observe how

the invertebrate populations are influenced by these conditions.

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2. Objectives

The general objective of this study is to investigate if, and to what degree, woodlouse and

millipede communities are affected by environmental conditions in a natural environment.

With this in mind we state the following hypotheses:

1. Woodlouse and millipede community compositions influence leaf litter

decomposition.

2. Environmental conditions (moisture availability and temperature) influence

woodlouse and millipede communities in their ability to decompose leaf litter.

3. Changing environmental conditions induce a change in the type of leaf litter (high

or low quality) consumption.

4. Changing environmental conditions affect survivability of woodlouse and millipede

communities.

Additionally, we will discuss if results from laboratory experiments can be extrapolated to

the field.

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3. Materials and Methods

This study was performed at the Forest & Nature Lab; part of the department of Forest and

Water Management, and member of the Natural Capital research theme of the Faculty of

Bioscience Engineering at Ghent University, Belgium.

3.1 Study area

This field study was performed in the Aelmoeseneie forest (Figure 1), located between

Ghent and the Flemish Ardennes, in the territory of Melle and Oosterzele in Belgium. The

forest is an old mixed deciduous forest consisting mostly of Quercus robur L., Quercus rubra

L., Fagus sylvatica L., Larix kaempferi Carr., Castanea sativa Mill. and Acer pseudoplatanus L.

and consists of an uninterrupted area of 39,5 ha (Labo voor Bos & Natuur 2007). Several of

the surrounding fields have been planted with Tilia L., Quercus palustris Münchh., Populus L.,

Fraxinus excelsior L., Alnus glutinosa L. and Alnus incana L.. The largest part of the forest

dates back to 1775, and is managed as a multifunctional forest by the Forest & Nature Lab of

the University of Ghent (Labo voor Bos & Natuur 2011).

Figure 1. Map of Aelmoeseneie forest (Labo voor Bos & Natuur 2011)

3.2 Experimental setup

This study was for the most part based on previous laboratory experiments using

microcosms to test the effect of macro-invertebrates on litter decomposition (Cragg &

Bardgett 2001; Zimmer et al. 2005; Pieper & Weigmann 2008). Microcosms were created,

containing leaf litter and soil fauna, and placed in the field. Environmental conditions in the

field were manipulated using overhangs and open-top chambers.

3.2.1 Microcosms

The microcosms were newly constructed using PVC tube with a height of 10 cm and

diameter of 12 cm, resulting in a surface area of 113,10 cm². Both the top and bottom were

sealed with fiberglass gauze (1 mm x 2mm mesh) to allow the passing of moisture and

micro-organisms during the experiment. We added approximately 10 mg (dry mass) of

sycamore litter (Acer pseudoplatanus) and 2 mg (dry mass) of oak litter (Quercus robur) to

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each microcosm. To restart microbial activity on the dried leaf litter, we created a microbial

wash. Soil and leaf litter was taken from the study area and soaked in water for several days.

Soil and litter was filtered out and the solution was sprayed on the microcosms one day

before the start of the experiment. To start the experiment for soil fauna effects, 4 subsets

of microcosms were set up. Monocultures of woodlice and millipedes consisted of 10

individuals of woodlice and millipedes respectively, mixed cultures consisted of 5 individuals

of each and control microcosms contained no animals (Figure 2). Before being placed in the

field, the microcosms were sprayed with the microbial wash again. Experimental density of

the animals equaled 885 individuals per m², similar to densities frequently found in the field

(Zimmer et al. 2005).

Figure 2. Preparing of microcosms (left: Tom Van de Weghe; right: Pallieter De Smedt)

To obtain data for a time series of litter decomposition on 6 separate occasions (after 1, 2, 4,

6, 8 and 12 weeks), and 3 replicates, we set up a total of 288 microcosms. The first replicate

was placed in the field in autumn, after the peak in litter fall, on October 26th, with the

second and third replicate placed respectively 1 and 3 days later. Microcosms were placed

randomly using Random.org (Haahr & Haahr 1998). After 1, 2, 4, 6, 8 and 13 weeks (due to

timing issues the last measurements were postponed until 13 weeks), three replicates for

every combination of fauna and environmental treatment were removed from the field. The

last microcosms of replicate 1 were removed January 25th. Soil fauna were removed and

weighed, and leaf litter was sorted and dried at 26°C for 3 days. After which dry mass was

measured.

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3.2.2 Soil fauna

Oniscus asellus L. (Figure 3) and

Glomeris marginata (Villers) (Figure 4)

were chosen to represent woodlice

and millipedes respectively. Both are

forest species and very prevalent in

the study area. Oniscus asellus is one

of the most widespread woodlice

species in Belgium, and can be found

in both deciduous and coniferous

forests and urban environments (Berg

et al. 2008). They aggregate under

dead wood, loose bark, rocks and leaf

litter. O. asellus is more moisture

dependant than other common

woodlice species such as its sympatric

species Porcelio scaber (Zimmer &

Topp 2000). Additionally, they are less

tolerant to rising ground water and

are therefore not present in swampy

areas. On average, they spend more

time burrowing deeper underground,

under dead wood and leaf litter and

do not climb trees as high as P. scaber

(Berg et al. 2008). Glomeris marginata

is also widely spread in Belgium and

prevalent in the study area, the highest densities can be found in natural deciduous forests

with limestone. They are rarely found under bark, usually under rocks, dead wood and litter

at the base of trees. Glomeris marginata is heat dependent and prefers well-drained soil.

They can primarily be found in relatively dry areas, where leaf litter is mixed by earthworms

(Berg et al. 2008; Voigtländer & Düker 2001).

Animals were collected by hand during mid to late October 2015 in small forest fragments

near Brakel, Belgium and around the study area (Figure 5). They were kept up to a maximum

of 1 week in plastic containers with soil and leaf litter collected on site. Pregnant females

were not used to prevent a sudden increase of juveniles during the experiment. The

difference between the average animal weight before and after the experiments served as a

measure for animal condition.

Figure 3. Oniscus asellus, 2010-09-19 Lobith - Tuindorp, havens © Martien van Berge

Figure 4. Glomeris marginata, 2014-04-26 Les Monts (Couvin) © Bert Van Der Krieken

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Figure 5. Collection areas: Bergstraat, Brakel (A) and Geraardbergsesteenweg, Gontrode (B). © 2016 Google

3.2.3 Leaf litter

Based on their chemical and physical characteristics (Table 1), leaf litter of oak (Quercus

robur) and Sycamore (Acer pseudoplatanus) were selected as respectively low quality and

high quality litter. Freshly fallen leaves were collected using nets to avoid early

decomposition of the leaves before the experiment. Collecting was done in semi-rural areas

in Hoogstraten and Bonheiden, Belgium in October 2015. In the laboratory, leaf litter was

dried at 26°C for several days to minimize microbial degradation (Zimmer & Topp 2000;

Zimmer et al. 2005). After termination of the experiments, litter remnants were dried again

at 26°C for 3 days. The difference between litter input (dry mass) to the microcosms and

litter remnants (dry mass) was used as a measure for leaf degradation. The characteristics of

the leaf litter (Table 1) were determined once prior to microcosms experiments. Lignin levels

were determined after Van Soest et al. (1991). C/N ratio was calculated after determination

of total nitrogen and organic carbon.

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Table 1. Characteristics of experimental leaf litter

Units Oak Sycamore

Potassium mg/kg 6982,68 8880,71

Sodium mg/kg 113,33 16,67

Calcium mg/kg 8977,08 12199,40

Magnesium mg/kg 221,48 566,31

Aluminium mg/kg 127,33 172,62

Iron mg/kg 185,91 288,69

Phosphate mg/kg 3209,92 1136,17

Organic carbon % 47,54 47,35

Nitrogen % 1,72 2,01

C/N

27,72 23,60

Lignin % 23,00 16,30

Oak litter showed comparable characteristics with litter used in previous experiments in

terms of C/N ratio and lignin level (Zimmer et al. 2005). Sycamore litter showed a higher C/N

ratio than most high quality litters used in previous experiments, but showed overall higher

counts of trace elements and lower levels of lignin. Furthermore, exploratory experiments

(unpublished) performed over the course of 2 and 8 weeks during August and September

2015 resulted in a faster rate of decomposition of sycamore compared to oak litter,

confirming sycamore litter as more easily decomposable and high quality litter.

3.2.4 Moisture and temperature manipulation

To manipulate moisture and temperature conditions in the field we used overhangs (Taylor

et al. 2004) and open-top chambers (Marion et al. 1997) respectively (Figure 6). Overhangs

were constructed out of 1 m² plastic sheets and were placed approximately 1 m above the

ground. Overhangs were removed biweekly to avoid simulating a complete drought. Open-

top chambers consisted of 6 Plexiglas sheets. To combine moisture and temperature

treatments overhangs were placed over open-top chambers. Rainfall was collected and

measured weekly to prevent overflow, temperature was measured on the soil surface, just

beneath the leaf litter layer. Soil moisture was measured using a soil moisture sensor. Before

placing microcosms, leaf litter was removed to allow full contact of the microcosms with the

soil.

Table 2 Overview of methods used to influence environmental conditions.

Code Overhang Open-top chamber

Natural environment N Moisture treatment M X Temperature treatment T X Combination moisture and temperature treatment C X X

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Figure 6. Field setup for moisture and temperature treatments: Natural conditions (A), Moisture treatment (B), Temperature treatment (C), Combination of moisture and temperature treatments (D).

3.3 Statistical analysis

Data was analyzed using R version 3.2.3 (R Core Team et al. 2016). General Linear Mixed

Models (GLMM) were used to test if environmental treatments were successful in

manipulating moisture and temperature levels, and to test differences in leaf litter

decomposition caused by fauna and environmental treatments. GLMM were also used to

test if fauna mortality and weight difference were affected by environmental and fauna

treatments. Factorial design was used for all treatment combinations, plot locations,

replicates and time measurements. Replicate number and plot location were considered

random factors in the GLMM. The lmer function of the lme4 package (Bates et al. 2015) was

used for all the above analyses. When the models indicated a significant difference between

means, the glht function with Tukey-adjust of the multcomp package (Hothorn et al. 2016)

was used for multiple comparison between means. Graphical representations of the data

were constructed using the ggplot2 package (Wickham 2009).

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4. Results

Results of the experiment are summarized in Table 3 (see Addendum). The results of five

microcosms were omitted for having been destroyed in the field (see Table 3, indicated in

red).

4.1 Manipulation of environmental conditions

To determine the effectiveness of the overhangs and open-top chambers in manipulating

the environmental conditions, we related the different treatments and time to the

measurements of the environmental conditions.

4.1.1 Rainfall

Analysis of the average weekly rainfall revealed a significant response to the treatments

used to influence moisture (Table 4, Figure 7). Post hoc analysis confirmed a significant

decrease in rainfall due to the overhangs used compared to the natural environment

(N-C: Estimate = 52,58 , p < 0,001 ; N-M: Estimate = 53,00 , p < 0,001). Open-top chambers

alone did not cause a significant decrease in rainfall (T-N: Estimate = 6,83 , p = 0,777). After

13 weeks, moisture and combination treatments caused a 36,05% and 37,76% reduction of

rainfall compared to natural conditions respectively. Temperature treatments only caused a

4,43% reduction.

Table 4. Results of analysis of variance for average weekly rainfall measures according to environmental treatment and time.

SS df F P

Treatment 312907,0 3 336,57 < 0,001

Time 1995280,0 5 1287,69 < 0,001

Treatment:Time 38541,0 15 8,29 < 0,001

The F values for the main effects and their interactions are presented, together with their level of significance.

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Figure 7. Effect of different environmental treatments on average weekly rainfall (C: combination treatment; M: moisture treatment; N: natural environment; T: temperature treatment). Significance values of treatment compared to natural environment are given.

4.1.2 Soil Moisture

Moisture treatments showed a significant decrease in soil moisture (Table 5, Figure 8).

However, overhangs alone did not sufficiently reduce soil moisture levels

(N-M: Estimate = 7,30 , p = 0,102), the combination of both overhangs and open-top

chambers did significantly lower soil moisture (N-C: Estimate = 11,78, p = 0,001). Open-top

chambers alone did not cause a significant decrease in soil moisture compared to the natural

environment (T-N: Estimate = -3,54 , p = 0,682). After 13 weeks, moisture treatments caused

a 7,63% reduction in soil moisture, temperature treatments caused a 12,01% reduction and

combination treatments induced a reduction of 24,06% of soil moisture compared to natural

conditions.

Table 5. Results of analysis of variance for soil moisture measures according to environmental treatment and time.

SS df F p

Treatment 1383,5 3 12,68 0,019

Time 10186,8 5 56,01 < 0,001

Treatment:Time 1170,0 15 2,14 0,009


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Figure 8. Effect of different environmental treatments on soil moisture (C: combination treatment; M: moisture treatment; N: natural environment; T: temperature treatment). Significance values of treatment compared to natural environment are given.

4.1.3 Temperature

The use of open-top chambers caused a significant rise in temperature compared to the

natural conditions (Table 6, Figure 9) (T-N: Estimate = 0,51 , p < 0,001 ; N-C: Estimate = -0,48,

p < 0,001). Overhangs alone did not cause a significant change in temperature

(N-M: Estimate = -0,005 , p = 0,999). On average, moisture treatments caused a 0,03%

increase in temperature, while temperature and combination treatments caused a 4,63%

and 4,39% increase respectively compared to natural conditions. While both time and

environmental treatments had a significant effect on temperature, no significance was found

with their interaction.

Table 6. Results of analysis of variance for temperature measures according to environmental treatment and time.

SS df F p

Treatment 17,7 3 132,28 < 0,001

Time 234,2 5 1048,13 < 0,001

The F values for the main effects are presented, together with their level of significance.

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Figure 9. Effect of different environmental treatments on temperature (C: combination treatment; M: moisture treatment; N: natural environment; T: temperature treatment). Significance values of treatment compared to natural environment are given.

4.2 Leaf litter decomposition

We visualized the leaf litter decomposition in two ways. Firstly, though the percentage mass

loss of litter and secondly through the mass loss of litter per gram biomass of macro-

detritivores added to the microcosms, the latter was done to account for differences in

macro-detritivore weight between microcosms. Both visualizations were conducted

separately on high and low quality leaf litter.

4.2.1 High quality litter decomposition

There were significant differences in percentage mass loss of Acer pseudoplatanus between different environmental treatments (Table 7, Figure 10), moisture treatments significantly decreased mass loss compared to natural environments (N-M: Estimate = 2,17 , p = 0,003 ; N-C: Estimate = 2,42 , p < 0,001). Temperature treatment alone showed no significant difference (T-N: Estimate = -0.8015 , p = 0,565) and there was a significant difference between sole temperature treatments and combination treatments (T-C: Estimate = 1,62 , p = 0,043). As expected, time also showed a significant effect, with a higher mass loss at later time periods. Different treatments with macro-detritivore populations initially showed a significant difference in mass loss, post-hoc analysis however revealed no significant difference of macro-detritivore populations on mass loss of leaf litter compared to control microcosms (MP-CO: Estimate = 1,21 , p = 0,799 ; WL-CO: Estimate = 1,07 , p = 0,854 ; MX-CO: Estimate = 1,40 , p = 0,721). Interaction between time and macro-detritivore populations did reveal a greater effect of macro-detritivore populations at later times (2-1: Estimate = 3,94 , p = 0,037 ; 4-1: Estimate = 10,71 , p < 0,001 ; 6-1: Estimate = 15,15 , p < 0,001 ; 8-1: Estimate = 17,71 , p < 0,001 ; 13-1: Estimate = 25,52 , p < 0,001).

16

Figure 10. Effect of different environmental treatments and macro-detritivore populations on percentage of Acer leaf litter mass loss (C: combination treatment; M: moisture treatment; N: natural environment; T: temperature treatment). Significance values of treatment compared to natural environment, and significance values of fauna treatments compared to control groups are given.

When mass loss was expressed per gram biomass of macro-detritivores added, both

woodlice and millipede populations showed a significant effect on litter decomposition. In

both cases, mixed cultures of macro-detritivores had a greater effect on litter mass loss than

monocultures (Figure 11, Figure 12). However, woodlice contributed to these effects more

than millipedes (WL-MX: Estimate = -2,78 , p = 0,021 ; MX-MP: Estimate = 1,88 , p = 0,036).

Different environmental treatments did not significantly affect woodlice populations when

mass was expressed per gram macro-detritivore biomass added, as environmental

treatments were not implemented into the model, but did affect mass loss with millipede

populations (Table 7, Figure 11, Figure 12). When mass loss was expressed per gram

millipede biomass, combination treatments of environmental conditions significantly

decreased litter mass loss compared to natural environments (N-C: Estimate = 1,77 ,

p = 0,006 ; N-M: Estimate = 0,589 , p = 0,696 ; N-T: Estimate = -0,567 , p = 0,717). In all cases

the interaction between macro-detritivore cultures and time showed a significant increase in

litter mass loss with increasing time. Woodlice populations showed a significant response

from week 4 (2-1: Estimate = 2,64 , p = 0,269 ; 4-1: Estimate = 6,33 , p < 0,001 ; 6-1: Estimate

= 8,54 , p < 0,001 ; 8-1: Estimate = 9,75 , p < 0,001 ; 13-1: Estimate = 18,36 , p < 0,001).

Millipede populations started to show a significant response from week 6

(2-1: Estimate = 1,14 , p = 0,820 ; 4-1: Estimate = 1,94 , p = 0,260 ; 6-1: Estimate = 3,47 ,

p = 0,002 ; 8-1: Estimate = 3,303 , p = 0,003 ; 13-1: Estimate = 5,44 , p < 0,001).

17

Table 7. Results of analysis of variance for high quality leaf litter mass loss according to environmental treatment, macro-detritivore populations and time.

SS df F p

Mass loss (%) Treatment 212,2 3 6,76 0,001

Population 1681,3 3 53,55 < 0,001

Time 29019,9 5 554,57 < 0,001

Population:Time 680,2 15 4,33 < 0,001

Mass loss / woodlouse biomass Population 1585,7 1 181,02 < 0,001

Time 2527,9 5 57,72 < 0,001

Population:Time 400,2 5 9,14 < 0,001

Mass loss / millipede biomass Treatment 55,6 3 3,86 0,020

Population 531,6 1 110,71 < 0,001

Time 759,2 5 31,62 < 0,001

Population:Time 55,0 5 2,29 0,049


Figure 11. Effect of different environmental treatments and macro-detritivore populations on Acer leaf litter mass loss per gram woodlice biomass added to microcosms (C: combination treatment; M: moisture treatment; N: natural environment; T: temperature treatment). Significance value of mixed cultures compared to monocultures is given.

18

Figure 12. Effect of different environmental treatments and macro-detritivore populations on Acer leaf litter mass loss per gram millipede biomass added to microcosms (C: combination treatment; M: moisture treatment; N: natural environment; T: temperature treatment). Significance values of treatment compared to natural environment, and significance values of mixed cultures compared to monocultures are given.

4.2.2 Low quality litter decomposition

Neither environmental treatments nor macro-detritivore cultures had a significant effect on

the percentage mass loss of Quercus robur litter. Different time-periods did have a

significant effect, as well as the interaction between time and different environmental

treatments (Table 8, Figure 13).

However, when mass loss was expressed per gram woodlice biomass added, macro-

detritivore populations caused a significant increase in Quercus litter mass loss. Mixed

cultures increased mass loss to a greater extent than woodlice monoculture

(WL-MX: Estimate = -0,432 , p = 0,005). Later time periods also significantly increased leaf

litter decomposition. Interaction between time and macro-detritivore populations indicated

a stronger effect of woodlice populations in later time periods (Table 8, Figure 14).

Environmental treatments did not show any significance to be admitted into the model.

When expressed per gram millipede biomass added, Quercus litter mass loss appeared to be

significantly affected by macro-detritivore cultures, different environmental treatments and

time (Table 8, Figure 15). Post hoc analysis however, showed no significant effect of

environmental treatments (N-M: Estimate = -0,095 , p = 0,965 ; T-N: Estimate = 0,077 ,

p = 0,981 ; N-C: Estimate = 0,016, p = 1,000) or between time periods. Also no significant

effect was revealed between macro-detritivore monocultures and mixed cultures

(MX-MP: Estimate = 0,118 , p = 0,558).

19

Figure 13. Effect of different environmental treatments and macro-detritivore populations on percentage of Quercus leaf litter mass loss (C: combination treatment; M: moisture treatment; N: natural environment; T: temperature treatment).

Table 8. Results of analysis of variance for low quality leaf litter mass loss according to environmental treatment, macro-detritivore cultures and time.

SS df F p

Mass loss (%) Treatment 45,5 3 1,66 0,223

Population 5,7 3 0,21 0,890

Time 5373,7 5 117,72 < 0,001

Treatment: Population 138,9 9 1,69 0,091

Treatment: Time 240,9 15 1,76 0,041

Population: Time 65,3 15 0,48 0,951

Treatment: Population: Time 733,2 45 1,79 0,003

Mass loss / woodlouse biomass Population 16,1 1 111,44 < 0,001

Time 18,0 5 24,88 < 0,001


Mass loss / MP biomass Treatment 0,8 3 4,40 0,005

Population 7,6 1 126,34 < 0,001

Time 4,7 5 15,48 < 0,001


Treatment: Time 1,5 15 1,71 0,055




20

Figure 34. Effect of different environmental treatments and macro-detritivore populations on Quercus leaf litter mass loss per gram woodlice biomass added to microcosms (C: combination treatment; M: moisture treatment; N: natural environment; T: temperature treatment). Significance values of mixed cultures compared to monocultures are given.

Figure 15. Effect of different environmental treatments and macro-detritivore populations on Quercus leaf litter mass loss per gram millipede biomass added to microcosms (C: combination treatment; M: moisture treatment; N: natural environment; T: temperature treatment). Significance values of treatment compared to natural environment, and significance values of mixed cultures compared to monocultures are given.

21

4.3 Macro-detritivore weight differences

Different environmental treatments, macro-detritivore cultures and time periods did not

show a significant effect on woodlice weight difference. However, there was a significant

effect by both environmental treatment and macro-detritivore culture interaction, and

environmental treatment and time interactions (Table 9, Figure 16). Interaction between

temperature treatment and woodlice monocultures showed a small decrease in woodlice

weight difference (TRTMNT(T):POP(WL): Estimate = -0,000355 , p = 0,047). Also interactions

between time period 6 and temperature treatment, moisture treatment and natural

environment showed significant effect (TRTMNT(N):time.f(6): Estimate = 0,018766 , p =

0,00294 ; TRTMNT(M):time.f(6): Estimate = 0,017706 , p = 0,006 ; TRTMNT(T):time.f(6):

Estimate = 0,017216 , p = 0,00803 ).

Table 9. Results of analysis of variance for woodlice weight difference according to environmental treatment, macro-detritivore populations and time.

SS df F p

Treatment 0,000029 3 0,31 0,819

Population 0,000024 1 0,78 0,379

Time 0,000120 5 0,77 0,575

Treatment:Population 0,000268 3 2,86 0,039

Treatment:Time 0,000961 15 2,05 0,016


Figure 16. Effect of different environmental treatments and macro-detritivore populations on woodlice weightdifference (C: combination treatment; M: moisture treatment; N: natural environment; T: temperature treatment). Significant values between population and environmental treatments are shown.

22

Neither environmental treatments, macro-detritivore cultures or time periods, nor any

interactions, showed a significant effect on millipede weight difference (Table 10, Figure 17).

Table 10. Results of analysis of variance for millipede weight difference according to environmental treatment, macro-detritivore populations and time.

SS df F p

Treatment 0,0004103 3 0,906 0,440

Population 0,0000005 1 0,003 0,956

Time 0,0010275 5 1,361 0,243


Figure 17. . Effect of different environmental treatments and macro-detritivore populations on millipede weight difference (C: combination treatment; M: moisture treatment; N: natural environment; T: temperature treatment). No significant values of treatment compared to natural environment, nor significant values of mixed cultures compared to monocultures could be shown.

4.4 Macro-detritivore survival rate

Initially, environmental treatments and time appeared to have a significant influence on

woodlice survival rate. Additionally, interactions between treatments and time, different

population composition and time, and the three-way interaction between treatments,

populations and time significantly influenced woodlice survival (Table 11, Figure 18).

However, post hoc analysis of environmental treatments showed no significant effect of any

kind. In similar fashion, millipede survival rate initially showed to be significantly influenced

by time, interaction between time and environmental treatments, and the three-way

interaction between treatments, population compositions and time (Table 11, Figure 19).

And again, post-hoc revealed no significant effect.

23

Table 11. Results of analysis of variance for millipede and woodlice survival rate according to environmental treatment, macro-detritivore populations and time.

SS df F p

Woodlice survival rate Treatment 1019,9 3 3,103 0,029

Population 0,0 1 < 0,001 0,995

Time 1687,5 5 3,081 0,011


Treatment: Time 3045,4 15 1,853 0,033

Population: Time 1263,7 5 2,307 0,048


Millipedes survival rate Treatment 231,6 3 1,464 0,247

Population 55,4 1 1,051 0,307

Time 887,4 5 3,366 0,007


Treatment: Time 2648,0 15 3,348 < 0,001

Population: Time 322,1 5 1,222 0,302

Treatment: Population: Time 1973,6 15 2,495 0,003 The F values for the main effects and their interactions are presented, together with their level of significance.

Figure 18. Effect of different environmental treatments and macro-detritivore populations on woodlice survival rate (C: combination treatment; M: moisture treatment; N: natural environment; T: temperature treatment). No significant values of treatment compared to natural environment, nor significant values of mixed cultures compared to monocultures could be shown.

24

Figure 19. Effect of different environmental treatments and macro-detritivore populations on millipede survival (C: combination treatment; M: moisture treatment; N: natural environment; T: temperature treatment). No significant values of treatment compared to natural environment, nor significant values of mixed cultures compared to monocultures could be shown.

25

5. Discussion

5.1 Environmental treatment effectiveness

To assure that we can use the different treatments to determine the effects of

environmental conditions on soil fauna and leaf litter decomposition, we must first

determine if these treatments were effective in influencing temperature and moisture

conditions during the experiment. Open-top chambers used during the experiment caused a

temperature rise of around 0,5°C. Earlier experiments conducted with open-top chambers

documented temperature increases of 1,2 – 1,8°C with a maximum of 5°C (Marion et al.

1997). Warming effects of open-top chambers are caused by solar radiation and protection

from wind. The lower than expected temperature measurements can be attributed to

shorter daytime warming during winter (Marion et al. 1997). Overhangs placed in the field

reduced weekly precipitation comparable to earlier experiments (Taylor et al. 2004).

However, soil moisture was only significantly influenced in situations with both open-top

chambers and overhangs.

The objective of using open-top chambers and overhangs was to simulate environmental

conditions based on predictions of climate change for the next century. Temperature

predictions of a 2,7°C increase (Boer et al. 2000; IPCC 2007) were not achieved by the

temperature treatments used during the experiment. Contrary to this, overhangs decreased

average precipitation to a point below predictions made by climate change models (Boer et

al. 2000; IPCC 2007), while soil moisture levels, although only achieved in combination

treatments, closely resemble predictions made about soil moisture availability (Boer et al.

2000).

Although the environmental treatments used were not able to simulate climate change

predictions for the next century, temperature and precipitation levels were influenced to a

degree to simulate short term climate change. Similar experiments conducted in laboratory

conditions did show comparable temperature and moisture conditions (Taylor et al. 2004;

van Geffen et al. 2011; Riutta et al. 2012; Collison et al. 2013; Dixie et al. 2015) to simulate

stressful conditions for soil fauna. With this, we can conclude that treatments used during

the experiment were sufficient to determine environmental effects on the ability of soil

fauna to decompose leaf litter.

5.2 Leaf litter decomposition by soil fauna

The positive effect of macro-detritivore on leaf litter decomposition is broadly accepted and

has been proven multiple times in laboratory experiments (Cragg & Bardgett 2001; Zimmer

et al. 2005; van Geffen et al. 2011; Vos et al. 2011; Collison et al. 2013; Riutta et al. 2012).

Contrary to these findings, our field study revealed no significant effect of macro-detritivore

populations on the percentage mass loss of both high quality and low quality leaf litter

26

compared to control setups, although graphical representation of data did imply a positive

effect of the fauna added.

The difference between our field study findings and the laboratory findings, as well as the

lack of statistical significance, can likely be attributed to the type of microcosms used in the

experiment. While woodlice and millipedes from the outside environment were halted by

the mesh size used, springtails and earthworms were able to enter microcosm and influence

leaf litter decomposition, as opposed to the absence of other invertebrates during

laboratory experiments.

However, when expressed per gram of macro-detritivore biomass added to the microcosms,

all macro-detritivore treatments (both mono- and mixed cultures) significantly increased

litter mass loss. Woodlice caused a greater net-effect effect per gram biomass than

millipedes, showing an even greater effect within mixed cultures. This supports the theories

that a greater macro-detritivore body mass and macro-detritivore identity are an important

factor in the increase of decomposition rates (van Geffen et al. 2011). Our findings also

partly coincide with Cragg and Bardgett (2001), who stated litter decomposition in mixed

cultures being mainly driven by the dominant animal present (our findings suggesting

woodlice being the dominant species in their ability to decompose leaf litter), but species

richness maintaining a stronger effect.

In previous laboratory studies, the effect of macro-detritivores on litter decomposition has

been shown to be more pronounced in low quality litter than in high quality litter (Cárcamo

et al. 2000). This effect has been ascribed to high quality litter being easily decomposable

and not further facilitated by the presence of macro-detritivores (Tian et al. 1995). Our

findings in the field seemingly contradict these results. All faunal treatments, both

monocultures and mixed cultures showed a stronger effect in high quality Acer litter

compared to the low quality Quercus litter. Along with a lower mass loss, no visual

fragmentation could be observed in Quercus litter, even after a period of 13 weeks in the

field. It must be noted that during our study, both high and low quality litter were presented

at the same time. And the lack of fragmentation of Quercus litter could simply be caused by

macro-detritivore preference towards high quality Acer litter. To fully determine the

difference in effect of soil fauna on high or low quality litter, future research with a similar

setup but separated litter treatments is recommended.

5.3 Environmental effects on soil fauna effectiveness

In high quality litter, moisture treatments caused a general decrease in leaf litter mass loss.

However, there was no significant interaction between soil fauna and environmental

treatments used. Contrary to previous studies (Collison et al. 2013), moisture conditions did

not show a clear modification of macro-detritivore behavior. Woodlice in particular were

surprisingly little affected by drier conditions, while these have shown to have a strong

sensitivity to unfavorable conditions (Zimmer 2005; Dixie et al. 2015).

27

These results not only extended to woodlice ability for leaf litter breakdown. When looking

at the weight differences from before and after the experiment, woodlice showed no

significant change induced by moisture treatments. Only in temperature treatments were

we able to see weightloss. And this with woodlice generally showing a positive effect to a

rise in temperature when moisture is not a limiting factor (David & Handa 2010). Millipede

communities, while being generally better adapted to harsher environments (Wright &

Westh 2006), were affected by environmental conditions in their ability for litter

decomposition. A significant decrease in leaf litter mass loss per gram millipedes added was

noted when temperature and moisture treatments were combined. However, no

environmental treatments affected millipede weightloss to a significant degree, confirming

millipede’s physiological adaptation to harsher environments (Wright & Westh 2006). The

decrease in leaf litter decomposition by millipedes combined with their condition being

unaffected by environmental conditions are also in line with the behavioral changes these

species undergo when confronted with unfavorable conditions. Millipedes are inclined to

remain inactive during these periods to preserve energy and only venture out when

conditions improve (Davis et al. 1977).

These findings on macro-detritivore effects on leaf litter decomposition were only confirmed

for low quality litter, where both woodlice and millipede communities seemed unaffected by

the environmental treatments used.

It is important to note that, while precipitation was successfully influenced by the overhangs

used, the surrounding natural environment may have acted as a buffering factor. Humidity

could not be controlled in the setups used and this may have kept moisture levels in the

microcosm at a high enough level to buffer the lack of precipitation. It should also be

mentioned that the observed moisture and temperature effects were measured during

autumn and winter, exploratory experiments (unpublished) performed in summer prior to

this study did indicate greater effects of moisture and temperature on woodlice and

millipedes. However, these exploratory experiments were performed using the same type of

microcosms. As such we essentially blocked macro-detritivore ability to burrow into the soil

or other behavioral adaptations to unfavorable conditions, influencing the fauna to an

unnatural extent. Altogether, our findings are in line with other experimental studies

running for several months and years that found soil fauna relatively unaffected by moisture

treatments (Taylor et al. 2004; Staley et al. 2007).

Given the importance of macro-detritivore communities for nutrient cycling and nutrient

uptake by plants (Bardgett & Chan 1999; Pieper & Weigmann 2008; Meyer et al. 2011), our

findings indicate that woodlice and millipedes would still be able to perform these functions

in light of short term climate change. The experiment ran during autumn and winter months

with a peak litter volume. Resistance of these species to short term environmental changes

would form a buffer to maintain a stability for nutrient cycling during these peak litter

periods in already fragmented forests for the coming decades.

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5.4 Shift in litter preference under different environmental conditions

As stated above, macro-detritivore effect on litter decomposition has been shown to be

more pronounced in low quality litter (Tian et al. 1995; Cárcamo et al. 2000). To explain

these findings, ‘compensatory feeding’ has been put forward, i.e. soil fauna increases it’s

consumption of low quality litter to meet their nutrient requirements in unfavorable

conditions (Coûteaux et al. 1991; Hattenschwiler et al. 1999). Our findings however, showed

a stronger decomposition of high quality litter on all accounts compared to low quality litter

decomposition. Both environmental and faunal treatments have shown little effect on

Quercus-litter, along with few visual sings of animal activity. Although in contrast with the

‘complementary feeding’ theory, our findings do coincide with previous studies that did not

show these macro-detritivore effects on low quality litter either (David et al. 2001; van

Geffen et al. 2011). It should be noted that in all microcosms both litter types were still

present. Low quality litter consumption, and effects of environmental conditions thereon,

might become more prevalent as high quality food sources become more scarce.

5.5 Macro-detritivore survival

Survival of both woodlice and millipedes was high. Out of all microcosms only five resulted in

survival rates below 60%. No environmental treatment, moisture, temperature or

combination thereof, was shown to have a significant effect on mortality. Millipede

communities showed a higher, but not significantly higher, survivability. This was to be

expected as millipedes have shown to be better adapted to low moisture environments

(Wright & Westh 2006). Previous studies also reported similar findings (Pieper & Weigmann

2008; Collison et al. 2013). Significant mortalities have been reported in soil fauna, but only

when animals were exposed to a 20-30% decrease in moisture levels combined with a

temperature rise of 5°C (Dixie et al. 2015). Similar situations have been observed in natural

environments in the past during long droughts and resulted in significant population declines

of both woodlice and millipede communities (David 1990; David et al. 1991). But these levels

of humidity drops and temperature rises, however, were not achieved in our experiment.

5.6 Notes on future research

The data obtained during this study provides ample opportunities for additional research.

While we did not find any clear relationship between environmental treatments and soil

fauna on litter decomposition, previous studies done under laboratory conditions have

shown a clear effect (Cragg & Bardgett 2001; Zimmer 2005; Zimmer et al. 2005; Pieper &

Weigmann 2008; Meyer et al. 2011; van Geffen et al. 2011; Riutta et al. 2012; Collison et al.

2013; Dixie et al. 2015). Temperature treatments did not reach a level to which soil fauna

would be sufficiently stressed to induce behavioral changes. The use of smaller cone

chambers, as opposed to hexagon chambers used in this experiment, may be able to raise

temperature levels to a higher stress point, similar to levels used in previous studies.

Additionally smaller mesh size can be used to prevent earthworms influencing leaf litter

29

decomposition to some degree. Finally, a longer time period would allow high quality leaf

litter to decompose to the point where macro-detritivores would experience a greater

competition for resources, which would be likely to reveal a more pronounced interaction

between the macro-detritivore populations.

6. Conclusion

The aim of this study was to investigate the influence of environmental conditions on macro-

detritivore communities and their ability for decomposing high- and low-quality leaf litter in

a natural environment. Additionally, we compared these results with laboratory experiments

to see if these can be extrapolated to the field. The most important findings of this study are

that:

Litter decomposition was significantly decreased by lower moisture levels in high

quality litter. Low quality litter was not significantly affected by environmental

conditions.

Woodlouse and millipede populations did not show to have a significant effect on

percentage mass loss of leaf litter, but did show a significant correlation when litter

was expressed per gram macro-detritivore biomass added.

Woodlouse and millipede communities’ ability to decompose leaf litter tended to be

negatively correlated to low moisture conditions. This pattern was however not

significant.

Woodlice were more proficient than millipedes in litter decomposition, both in

monocultures and mixed cultures.

We did not find a significant effect of environmental conditions on weightloss of

macro-detritivore communities.

Environmental conditions did not significantly affect macro-detritivore mortality.

In conclusion, it can be argued that, while still effectively increasing decomposition,

woodlouse and millipede influence in breaking down leaf litter has been overestimated in

laboratory experiments, and that leaf litter mass loss is mainly driven by larger communities

of soil fauna. Additionally, environmental conditions are less likely to drive soil fauna

behavior, growth and survival, with leaf litter quality being the determining factor in these

aspects.

30

7. Summary

Few of Europe’s forests remain without anthropogenic influences. Fragmentation and

climate change pose a great danger, as drought stress could potentially extend edge effects

deeper into the forest. These effects are already observed in certain sites in Germany where

native tree species already show strong drought stress.

This drought and temperature stress is not limited to flora, macro-detritivores living off leaf

litter are also influenced by the effects of climate change. Woodlice and millipedes, key

regulators of plant litter decomposition, contribute greatly to the biodiversity of macro-

detritivores. Both groups have behavioral and physiological coping mechanisms to withstand

periods of low moisture. Basic behavior is to burrow into the soil or take refuge in small

cavities or fallen deadwood. Physiological adaptations in millipedes include a reduced

metabolism and the ability to absorb water vapor in unsaturated air. Woodlice generally

show less adaptation to drought compared to millipedes. Despite all adaptations however,

both groups suffer from a decreased in growth and increase in mortality in dryer conditions.

Higher temperatures on the other hand generally show a positive effect on woodlice and

millipedes, with a higher survival rate, growth rate and larger offspring.

Apart from moisture and temperature, litter quality also greatly influences litter

decomposition by macro-detritivores. It has been demonstrated that macro-detritivore

species show food specialization and preference. Leaf litter with lower lignin concentration

and lower C/N ratio is classified as high quality litter and is generally more easily broken

down by detritivore fauna. Contrary to this, low quality litter has a relatively high lignin

concentration and C/N ratio.

The majority of research done on litter decomposition by macro-detritivores has been

conducted through laboratory experiments using microcosms in controlled environments,

litter and macro-detritivore compositions. The objective of our study was to determine if,

and to what degree, woodlouse and millipede communities are affected by environmental

conditions in a natural environment, and to what degree results of laboratory experiments

can be extrapolated to the field.

Microcosms were created and sealed with fiberglass gauze to allow the passing of soil

moisture and micro-organisms during the experiment. Ten mg of Acer pseudoplatanus and 2

mg of Quercus robur as high and low quality liter respectively were added. To start the

experiment for soil fauna effects, 4 subsets of microcosms were set up. Monocultures of

woodlice and millipedes consisted of 10 individuals of Oniscus asellus L. and Glomeris

marginata (Villers) respectively, mixed cultures consisted of 5 individuals of each and control

microcosms contained no animals. To manipulate moisture and temperature conditions in

the field we used overhangs and open-top chambers respectively. To combine moisture and

temperature treatments overhangs were placed over open-top chambers, control setups

were placed in the field with neither. A total of 288 microcosms were placed in the field

31

divided across 3 replicates, each containing 4 subsets of environmental treatment. Each

environmental subset was again divided into 4 smaller subsets of faunal treatments. One

microcosms of each environmental/faunal treatment combination per replicate was taken

out of the field after 1, 2, 4, 6, 8 and 13 weeks to be examined.

To determine how woodlouse and millipede communities influenced leaf litter

decomposition, we calculated the mass loss of litter between the start and end of the

experiment. Mass loss was expressed both in percentage mass loss and per gram biomass of

macro-detritivores added to the microcosm at the start of the experiment. The latter was

done to account for differences in macro-detritivore weight between microcosms. Macro-

detritivore populations did not show a significant effect on liter mass loss percentage,

contrary to results from laboratory experiments. This can most likely be attributed to the

presence of foreign macro-detritivores as they were able to enter the microcosms through

the gauze used and influence mass loss. Woodlice and millipede populations did show a

significant effect when mass loss was expressed per gram of macro-detritivore biomass

added, with woodlice showing a stronger effect than millipedes, and mixed cultures affecting

litter decomposition to a greater extent overall. This supports the theory of greater macro-

detritivore biomass being an important factor in litter decomposition rates. High quality

litter was consumed to a greater extent than low quality litter, in accordance to previous

studies. However, to fully determine the difference in effect of soil fauna on high or low

quality litter, future research with a similar setup but separated litter treatments is

recommended.

To asses environmental effects on soil fauna effectiveness litter mass loss was compared

between different environmental treatments, as well as macro-detritivore weightdifference

between start and end of the experiment. Overall, low moisture conditions induced a

decrease in leaf litter mass loss. However, macro-detritivores were surprisingly little affected

by drier conditions. No interaction was found between detritivore populations and

environmental treatment, contrary to previous studies. Woodlice weightloss was unaffected

by low moisture, and only showed a slight decrease in environments with higher

temperatures. These findings contradict previous studies stating that woodlice are strongly

limited in their ability to decompose litter in unfavorable environments. Millipede weightloss

was not affected by environmental treatments at all, coinciding with previous results. It is

important to note that the surrounding environment may have acted as a buffer to maintain

moisture levels to a degree where animal populations could be sustained. And further

experimentation during warmer, dryer periods in the year are recommended.

When investigating a shift in litter preference under different environmental conditions our

findings showed a stronger decomposition of high quality litter on all accounts compared to

low quality litter decomposition. Both environmental and faunal treatments have shown

little effect on Quercus-litter, along with few visual sings of animal activity. Our findings

coincide with previous studies that did not show these macro-detritivore effects on low

32

quality litter either. It should again be noted that in all microcosms both litter types were still

present. Low quality litter consumption, and effects of environmental conditions thereon,

might become more prevalent as high quality food sources become more scarce.

Survival of both woodlice and millipedes was high. No environmental treatment, moisture,

temperature or combination thereof, was shown to have a significant effect on mortality.

Previous studies also reported similar findings. Significant mortalities have been reported in

soil fauna only when animals were exposed to a 20-30% decrease in moisture levels

combined with a temperature rise of 5°C.

We can conclude that environmental conditions show little effect on woodlouse and

millipede weight and survival and their ability to decompose leaf litter. Litter mass loss

seems to be mainly driven by litter quality, with high quality litter breaking down more easily

that low quality litter. Woodlice and millipede influence for leaf litter decomposition,

although still effectively increasing litter breakdown, seems to have been overestimated in

laboratory experiments. And although woodlice do seem to contribute to a greater extent

than millipedes, they are but a part in a larger community of detritivores that uphold leaf

litter breakdown and nutrient cycling.

33

8. Samenvatting

Slechts een klein deel van Europa’s bossen zijn vrij van menselijke invloed. Fragmentatie en

klimaatsverandering vormen een reëel gevaar, drogere condities kunnen de randeffecten

inwaarts uitbreiden. Deze effecten worden nu al geobserveerd in bepaalde sites in Duitsland

waar lokale soorten al droogtestress ondervinden.

Deze droogte- en hittestress is niet enkel van toepassing op flora, ook invertebraten

afhankelijk van bladafval worden ook beïnvloed door klimaatsverandering. Pissebedden en

miljoenpoten zijn belangrijke regulatoren voor plantafbraak en zijn verantwoordelijk voor

een groot deel van de biodiversiteit van bladafbrekende macro-invertebraten. Beide

groepen hebben verschillende aanpassingen om droogtes te weerstaan. Doorgaans wordt er

ondergronds of onder dood hout geschuild. Miljoenpoten vertonen ook een trager

metabolisme terwijl pissebedden doorgaans minder fysiologische adaptaties vertonen.

Ondanks de aanpassingen vertonen beide groepen een tragere groei en hogere mortaliteit in

drogere omstandigheden. Een hogere temperatuur toont dan weer een positief effect, met

hogere overlevingskans, groei en grotere nakomelingen.

Naast vochtigheid en temperatuur is de kwaliteit van het bladafval ook een belangrijke

factor in bladafbraak. Bladafbrekende macro-invertebraten vertonen specialisatie en

voedselvoorkeur. Bladafval met een lage lignine concentratie en C/N ratio wordt

geclassificeerd als bladafval van hoge kwaliteit en wordt gemakkelijker afgebroken door

fauna. In tegenstelling tot bladafval van lage kwaliteit, gekenmerkt door een relatief hoge

lignine concentratie en C/N ratio.

Het merendeel van onderzoek rond bladafbraak door macro-invertebraten werd gedaan via

laboratoriumexperimenten met microcosms met gecontroleerde vochtigheid, temperatuur

en populaties van fauna. De doelstellig van onze studie was om na te gaan of, en in welke

mate, pissebedden en miljoenpoten beïnvloed worden door de omgevingscondities in een

natuurlijke omgeving, en in welke mate de resultaten van labexperimenten gelden in het

veld.

Microcosms werden afgesloten met glasvezel gaas om interactie van grondvochtigheid en

micro-organismen toe te laten tijdens het experiment. 10 mg Acer pseudoplatanus en 2 mg

Quercus robur werden toegevoegd als bladafval van respectievelijk hoge en lage kwaliteit. Bij

de start van het experiment rond de invloed van fauna werden 4 subsets van microcosms

gecreëerd. Monoculturen van pissebedden en miljoenpoten bestonden uit 10 individuen van

respectievelijk Oniscus asellus L. en Glomeris marginata (Villers), gemende culturen

bestonden uit 5 individuen van elk, de controleset bevatte geen individuen. Vochtigheid en

temperatuur werden beïnvloed door middel van respectievelijk een afdak en open-top

chambers. Combinatie van vocht- en temperatuurbehandeling werd bereikt door een afdak

te plaatsen boven de open-top chambers, controles werden zonder enige behandeling in het

veld geplaatst. In totaal werden 288 microcosms verdeeld over 3 replicaten. Elk replicaat

34

bestond uit 4 subsets van de omgevingsbehandelingen, waarvan elk bestond uit 4 subsets

van fauna behandeling. Van elke combinatie van omgeving- en fauna behandeling werd na 1,

2, 4, 6, 8 en 13 weken een microcosms uit het veld gehaald voor onderzoek. En dit voor elk

replicaat.

Om na te gaan hoe pissebedden en miljoenpoten bladafbraak beïnvloeden, werd het

massaverlies van het bladafval berekend. Het verlies werd uitgedrukt in het percentage aan

verloren massa, en in gram per gram fauna biomassa toegevoegd aan de microcosms aan

het begin van het experiment. Dit laatste om het effect van de verschillende gewichten te

minimaliseren. Bladafbrekende fauna toonde geen significant effect op het percentage

massaverlies, in tegenstelling tot labexperimenten. Dit verschil kan hoogstwaarschijnlijk

worden toegeschreven aan de aanwezigheid van vreemde fauna die door de mazen van het

gebruikte gaas konden passeren en de bladafbraak beïnvloedden. Pissebed en miljoenpoot

populaties gaven wel een significant effect aan wanneer het massaverlies uitgedrukt werd in

gram per toegevoegde biomassa, waarbij pissebedden een grotere invloed dan miljoenpoten

vertoonden. Gemengde populaties vertoonden in het algemeen een sterkere invloed op

bladafbraak. Dit bevestigt de theorie dat een grotere invertebrate biomassa een belangrijke

factor is voor de snelheid van bladafbraak. Bladafval van hoge kwaliteit werd in grotere mate

geconsumeerd dan bladafval van lage kwaliteit, in overeenstemming met vorige studies. Om

dit verschil verder te onderzoeken is verder onderzoek met een gelijkaardige set-up maar

gescheiden bladafval vereist.

Om het effect van de omgevingsvariabelen op de fauna’s mogelijkheid tot bladafbraak werd

het massaverlies van bladafval onderzocht tussen de verschillende subsets van

omgevingsbehandelingen. Ook werd het gewichtsverschil van de macro-detritivoren tussen

begin en einde van het experiment bepaald. Over het algemeen veroorzaakte een lage

vochtigheid een verminderde bladafbraak. Fauna werd echter verassend weinig beïnvloed

hierdoor. Er werd geen interactie gevonden tussen de invertebrate populaties en

omgevingsvariabelen, in tegenstelling tot vorig onderzoek. Gewichtsverlies bij pissebedden

werd niet beïnvloed door lage vochtigheid en werd slechts in kleine mate verlaagd door

hogere temperaturen. Deze bevindingen spreken vorige studies tegen die verklaren dat

pissebedden een sterk verminderde bladafbraak veroorzaken in niet-ideale

omstandigheden. Gewichtsverlies bij miljoenpoten werd niet beïnvloed door de

omgevingsomstandigheden, in overeenstemming met vorige studies. Het is belangrijk te

vermelden dat de luchtvochtigheid in het studiegebied als buffer zou kunnen dienen voor de

vochtigheid binnen de microcosms. Verder onderzoek tijdens warmere, drogere periodes is

aangeraden.

We onderzochten of omgevingsvariabelen een verschil in de kwaliteit van het bladafval

induceerden. Onze bevindingen toonden een sterkere decompositie van bladafval van hoge

kwaliteit. Zowel omgevings- als fauna behandelingen toonden geen significant effect op

bladafval van lage kwaliteit, samen met een gebrek aan visuele vraat. Onze bevindingen

35

stemmen overeen met vorig onderzoek die geen effect toont van macro-detritivoren op

bladafval van lage kwaliteit. Beide types waren aanwezig in de microcosms, het gebrek aan

effect op de lage kwaliteitsbladeren kan dus ook verklaard worden door een voorkeur voor

bladafval van hoge kwaliteit door de macro-detritivoren.

Pissebedden en miljoenpoten vertoonden een hoge overleving. Geen enkele

omgevingsbehandeling vertoonden geen effect op de mortaliteit. Vorige studies vertoonden

dezelfde bevindingen. Een significante verhoging van de mortaliteit werd wel aangetoond

wanneer fauna werd blootgesteld aan een verminderde vochtigheid van 20-30%

gecombineerd met een temperatuursstijging van 5°C.

We kunnen besluiten dat omgevingsvariabelen maar weinig effect vertoont op de

mortaliteit, gewicht en de mogelijkheid tot bladafbraak van pissebedden en miljoenpoten.

Bladafbraak wordt vooral beïnvloed door de kwaliteit van het bladafval, waarbij bladafval

van hoge kwaliteit gemakkelijker afbreekt dan bladafval van lage kwaliteit. De invloed van

pissebedden en miljoenpoten op bladafbraak, hoewel deze nog steeds een invloed

uitoefenen, lijkt overschat te worden in laboratoriumexperimenten. En hoewel pissebedden

een grotere impact dan miljoenpoten vertonen, zijn zij maar een onderdeel van de grote

gemeenschap van bladafbrekende bodembiota die bladafbraak en nutriëntencyclus

onderhouden.

36

9. Acknowledgements

I sincerely want to thank my tutor ir. Pallieter De Smedt for the thought-provoking

discussion and insightful comments, for his guidance and encouragement throughout the

last year, and for his help during the many hours of collecting woodlice and millipedes, leaf

litter and setting up the microcosms used. I would like to thank my supervisor Prof. dr. Dries

Bonte and co-supervisor Prof. dr. ir. Kris Verheyen for their encouragement and helpful

comments, and for giving me the opportunity to write this thesis. I would also like to thank

Prof. dr. ir. Pieter De Frenne for allowing me the use of his temperature measurements at

the study site, ir. Willem Proesmans for his help during the fauna collection, and Luc Willems

and Greet De bruyn for the chemical analysis of leaf litter. Furthermore I would like to thank

the entire staff of the ForNaLab for creating a welcoming environment.

My wholehearted thanks goes out to Melda Altunbay for her moral and emotional support

and willingness to lend an ear during the stressful moments. I would also like to thank Daan

Mertens for his help during the fauna collection, encouragement and near endless supply of

coffee. I also wish to express my gratitude towards my parents for their patience, support

and keeping up with my mood swings this last year. Finally, I would like to thank the rest of

my family and dearest friends for their continued support.

37

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41

11. Addendum

Table 3. Summary of results obtained during the experiment

CODE

Weeks in the field

BEFORE AFTER Moisture

levels

Average Temperature

(°C) DATE

Weight (g) Weight (g) Surviving Weight (g) Weight (g)

WL Total

MP Total Quercus Acer WL MP WL MP Quercus Acer

Soil (%)

Total rainfall (ml)

I-CO-N-1 1 NA NA 2,05 9,98 NA NA NA NA 1,92 9,33 35,1 72 11,72 2/11/15






I-CO-M-1 1 NA NA 1,92 10,13 NA NA NA NA 1,85 9,71 19,4 0 11,72 2/11/15






I-CO-T-1 1 NA NA 2,01 10,40 NA NA NA NA 1,90 9,40 22,7 66 12,16 2/11/15






I-CO-C-1 1 NA NA 2,00 9,98 NA NA NA NA 1,98 9,00 21,7 0 12,16 2/11/15






I-WL-N-1 1 0,464 NA 1,98 10,18 10 NA 0,479 NA 1,88 8,99 42,8 72 11,72 2/11/15

I-WL-N-2 2 0,480 NA 2,04 10,04 8 NA 0,477 NA 1,90 8,74 29,3 112 12,18 9/11/15

I-WL-N-4 4 0,532 NA 1,99 9,96 10 NA 0,556 NA 1,63 7,57 50,4 1047 12,14 23/11/15

I-WL-N-6 6 0,500 NA 1,93 9,91 5 NA 0,308 NA 1,60 6,82 38,5 1529 11,02 7/12/15

I-WL-N-8 8 0,339 NA 1,96 10,22 10 NA 0,395 NA 1,59 7,25 45,5 2177 10,72 21/12/15

I-WL-N-12 13 0,418 NA 1,91 9,88 10 NA 0,449 NA 1,48 5,82 48,3 3183 9,56 25/01/16

I-WL-M-1 1 0,377 NA 2,01 9,94 10 NA 0,402 NA 1,90 9,11 19,5 0 11,72 2/11/15

I-WL-M-2 2 0,444 NA 1,98 10,06 9 NA 0,405 NA 1,81 8,64 23,4 48 12,18 9/11/15

I-WL-M-4 4 0,441 NA 1,90 10,00 10 NA 0,472 NA 1,86 7,87 46,7 653 12,14 23/11/15

I-WL-M-6 6 0,388 NA 2,02 10,02 10 NA 0,423 NA 1,77 7,66 38,7 871 11,02 7/12/15

I-WL-M-8 8 0,370 NA 1,98 10,09 9 NA 0,407 NA 1,55 6,97 38,5 1553 10,72 21/12/15

I-WL-M-12 13 0,439 NA 1,98 10,08 10 NA 0,485 NA 1,61 6,25 48,5 1760 9,56 25/01/16

I-WL-T-1 1 0,411 NA 2,09 10,16 9 NA 0,402 NA 1,98 9,08 24,9 48 12,16 2/11/15

I-WL-T-2 2 0,366 NA 1,90 9,94 10 NA 0,397 NA 1,80 8,67 26,1 81 12,74 9/11/15

42

Table 3 continued

CODE

Weeks in the field


levels

Average Temperature

(°C) DATE


WL Total


Soil (%)

Total rainfall (ml)

I-WL-T-4 4 0,360 NA 1,97 10,03 9 NA 0,355 NA 1,71 7,72 50,3 1047 12,68 23/11/15

I-WL-T-6 6 0,420 NA 2,07 9,85 7 NA 0,329 NA 1,78 6,92 45,7 1403 11,54 7/12/15

I-WL-T-8 8 0,392 NA 1,97 10,00 8 NA 0,360 NA 1,66 6,80 41,6 1814 11,27 21/12/15

I-WL-T-12 13 0,308 NA 1,93 10,07 10 NA 0,342 NA 1,60 6,78 42,3 2765 10,04 25/01/16

I-WL-C-1 1 0,364 NA 1,95 9,74 10 NA 0,403 NA 1,78 8,98 30,8 0 12,16 2/11/15

I-WL-C-2 2 0,343 NA 2,02 9,99 9 NA 0,331 NA 1,75 9,21 19,1 22 12,74 9/11/15

I-WL-C-4 4 0,347 NA 2,02 10,07 10 NA 0,399 NA 1,75 8,13 24,5 786 12,68 23/11/15

I-WL-C-6 6 0,375 NA 1,99 10,06 9 NA 0,376 NA 1,75 7,36 34,1 1138 11,54 7/12/15

I-WL-C-8 8 0,341 NA 2,00 10,18 10 NA 0,379 NA 1,65 7,27 38,2 1181 11,27 21/12/15

I-WL-C-12 13 0,348 NA 2,05 10,08 10 NA 0,405 NA 1,67 6,80 45,3 1937 10,04 25/01/16

I-MP-N-1 1 NA 0,973 2,04 9,99 NA 10 NA 0,769 1,94 8,94 41,7 39 11,72 2/11/15

I-MP-N-2 2 NA 0,745 2,00 10,00 NA 10 NA 0,744 1,89 8,06 40,5 85 12,18 9/11/15

I-MP-N-4 4 NA 0,692 1,96 10,07 NA 10 NA 0,740 1,69 7,42 38,3 1173 12,14 23/11/15

I-MP-N-6 6 NA 0,652 2,01 10,02 NA 10 NA 0,694 1,75 6,81 41,0 1552 11,02 7/12/15

I-MP-N-8 8 NA 0,704 1,97 10,03 NA 10 NA 0,752 1,58 5,72 52,1 2177 10,72 21/12/15

I-MP-N-12 13 NA 0,656 2,00 10,04 NA 10 NA 0,718 1,63 4,57 51,4 3248 9,56 25/01/16

I-MP-M-1 1 NA 0,604 1,96 10,07 NA 10 NA 0,626 1,77 9,44 27,1 0 11,72 2/11/15

I-MP-M-2 2 NA 0,614 1,96 9,97 NA 3 NA 0,157 1,89 8,99 30,3 21 12,18 9/11/15

I-MP-M-4 4 NA 0,659 1,91 9,92 NA 10 NA 0,677 1,65 7,51 29,9 653 12,14 23/11/15

I-MP-M-6 6 NA 0,601 2,10 9,85 NA 10 NA 0,638 1,84 6,61 41,1 1047 11,02 7/12/15

I-MP-M-8 8 NA 0,596 2,03 9,93 NA 10 NA 0,635 1,75 6,45 46,6 1193 10,72 21/12/15

I-MP-M-12 13 NA 0,717 1,93 9,93 NA 10 NA 0,734 1,67 5,06 49,1 1671 9,56 25/01/16

I-MP-T-1 1 NA 0,666 2,08 10,00 NA 10 NA 0,690 1,99 9,13 28,9 65 12,16 2/11/15

I-MP-T-2 2 NA 0,863 1,94 10,00 NA 10 NA 0,915 1,75 8,27 19,3 117 12,74 9/11/15

I-MP-T-4 4 NA 0,686 2,03 9,99 NA 10 NA 0,721 1,76 7,30 42,8 973 12,68 23/11/15

I-MP-T-6 6 NA 0,766 2,08 9,96 NA 9 NA 0,751 1,63 6,97 49,1 1576 11,54 7/12/15

I-MP-T-8 8 NA 1,098 1,95 10,04 NA 10 NA 1,178 1,65 5,76 32,8 1814 11,27 21/12/15

I-MP-T-12 13 NA 0,949 1,97 10,08 NA 10 NA 1,015 1,69 4,46 43,5 3458 10,04 25/01/16

I-MP-C-1 1 NA 0,693 1,92 9,93 NA 10 NA 0,669 1,83 9,06 19,1 0 12,16 2/11/15

I-MP-C-2 2 NA 0,560 1,95 10,02 NA 10 NA 0,550 1,69 8,38 31,5 83 12,74 9/11/15

I-MP-C-4 4 NA 0,580 2,02 9,96 NA 10 NA 0,572 1,85 8,00 46,9 801 12,68 23/11/15

I-MP-C-6 6 NA 0,640 1,96 9,98 NA 10 NA 0,632 1,69 7,44 29,7 1024 11,54 7/12/15

I-MP-C-8 8 NA 0,543 2,00 9,98 NA 10 NA 0,541 1,57 6,59 23,3 1117 11,27 21/12/15

I-MP-C-12 13 NA 0,574 1,94 10,04 NA 9 NA 0,480 1,63 6,05 34,4 1824 10,04 25/01/16

I-MX-N-1 1 0,136 0,251 1,92 9,89 5 5 0,155 0,275 1,75 8,81 28,7 72 11,72 2/11/15

I-MX-N-2 2 0,214 0,259 2,00 10,00 3 5 0,136 0,277 1,88 8,43 33,5 73 12,18 9/11/15

I-MX-N-4 4 0,171 0,536 2,08 9,83 5 5 0,213 0,562 1,84 7,20 58,0 1173 12,14 23/11/15

I-MX-N-6 6 0,267 0,351 2,09 9,91 5 5 0,292 0,337 1,75 7,33 30,9 1735 11,02 7/12/15

I-MX-N-8 8 0,274 0,283 1,91 9,93 5 5 0,279 0,282 1,56 6,77 51,1 1846 10,72 21/12/15

43

Table 3 continued

CODE

Weeks in the field


levels

Average Temperature

(°C) DATE


WL Total


Soil (%)

Total rainfall (ml)

I-MX-N-12 13 0,222 0,283 2,01 9,81 5 5 0,243 0,291 1,67 6,84 53,5 3693 9,56 25/01/16

I-MX-M-1 1 0,150 0,282 1,95 9,83 5 5 0,151 0,265 1,84 9,19 26,9 0 11,72 2/11/15

I-MX-M-2 2 0,245 0,280 1,94 10,10 5 5 0,251 0,273 1,78 9,04 43,3 85 12,18 9/11/15

I-MX-M-4 4 0,216 0,354 2,00 10,01 5 5 0,234 0,351 1,68 7,82 25,9 903 12,14 23/11/15

I-MX-M-6 6 0,146 0,319 1,92 9,91 4 5 0,139 0,327 1,63 7,66 40,2 1047 11,02 7/12/15

I-MX-M-8 8 0,111 0,277 1,91 9,98 5 5 0,142 0,290 1,61 7,42 51,0 1110 10,72 21/12/15

I-MX-M-12 13 0,152 0,245 2,07 10,12 5 5 0,192 0,236 1,73 6,23 45,2 1671 9,56 25/01/16

I-MX-T-1 1 0,153 0,223 2,00 9,84 4 5 0,148 0,237 1,80 8,93 45,9 60 12,16 2/11/15

I-MX-T-2 2 0,134 0,228 2,09 10,05 5 5 0,158 0,240 1,96 8,85 20,2 117 12,74 9/11/15

I-MX-T-4 4 0,168 0,185 1,92 9,75 5 5 0,218 0,216 1,68 7,88 53,9 1047 12,68 23/11/15

I-MX-T-6 6 0,171 0,224 2,06 9,79 5 1 0,206 0,097 1,77 7,51 34,1 1351 11,54 7/12/15

I-MX-T-8 8 0,178 0,181 1,95 9,86 4 5 0,175 0,199 1,65 7,45 42,3 1721 11,27 21/12/15

I-MX-T-12 13 0,104 0,280 1,93 9,96 5 5 0,137 0,289 1,70 5,93 48,9 3319 10,04 25/01/16

I-MX-C-1 1 0,200 0,305 1,99 9,94 5 5 0,242 0,326 1,91 9,21 23,8 0 12,16 2/11/15

I-MX-C-2 2 0,141 0,332 2,02 9,87 5 5 0,175 0,355 1,90 8,71 19,7 10 12,74 9/11/15

I-MX-C-4 4 0,243 0,345 1,98 10,02 5 5 0,248 0,358 1,75 7,80 39,1 888 12,68 23/11/15

I-MX-C-6 6 0,235 0,454 2,09 10,04 4 5 0,181 0,474 1,88 7,03 35,5 1024 11,54 7/12/15

I-MX-C-8 8 0,349 0,444 1,94 9,96 4 5 0,314 0,461 1,79 7,19 36,3 1052 11,27 21/12/15

I-MX-C-12 13 0,216 0,407 2,08 10,12 4 5 0,180 0,424 1,84 5,55 43,1 2126 10,04 25/01/16

II-CO-N-1 1 NA NA 1,91 9,94 NA NA NA NA 1,81 9,10 36,6 36 11,54 3/11/15






II-CO-M-1 1 NA NA 1,85 9,85 NA NA NA NA 1,75 9,21 38,1 0 11,54 3/11/15






II-CO-T-1 1 NA NA 2,09 9,60 NA NA NA NA 1,87 8,73 28,9 65 11,95 3/11/15






II-CO-C-1 1 NA NA 1,91 9,77 NA NA NA NA 1,75 9,00 22,2 0 11,95 3/11/15


44

Table 3 continued

CODE

Weeks in the field


levels

Average Temperature

(°C) DATE


WL Total


Soil (%)

Total rainfall (ml)





II-WL-N-1 1 0,657 NA 1,96 9,70 9 NA 0,485 NA 1,82 8,63 47,1 36 11,54 3/11/15

II-WL-N-2 2 0,508 NA 1,78 9,91 10 NA 0,552 NA 1,67 8,40 22,7 110 12,37 10/11/15

II-WL-N-4 4 0,294 NA 2,07 10,08 9 NA 0,323 NA 1,80 8,05 41,7 1177 11,98 24/11/15

II-WL-N-6 6 0,393 NA 1,87 9,67 9 NA 0,423 NA 1,59 6,61 33,9 1352 10,99 8/12/15

II-WL-N-8 8 0,430 NA 2,08 10,37 8 NA 0,373 NA 1,80 7,55 41,9 1662 10,71 22/12/15

II-WL-N-12 13 0,430 NA 2,00 10,06 10 NA 0,490 NA 1,60 6,62 51,2 3248 9,52 26/01/16

II-WL-M-1 1 0,444 NA 1,84 9,90 10 NA 0,495 NA 1,75 9,23 24,9 0 11,54 3/11/15

II-WL-M-2 2 0,666 NA 1,98 9,65 5 NA 0,287 NA 1,80 8,21 24,1 17 12,37 10/11/15

II-WL-M-4 4 0,595 NA 1,98 9,58 10 NA 0,419 NA 1,78 7,57 34,7 808 11,98 24/11/15

II-WL-M-6 6 0,315 NA 1,89 10,19 10 NA 0,381 NA 1,57 7,65 45,8 1197 10,99 8/12/15

II-WL-M-8 8 0,570 NA 1,94 9,71 10 NA 0,661 NA 1,56 6,37 47,4 1553 10,71 22/12/15

II-WL-M-12 13 0,332 NA 2,07 9,80 9 NA 0,377 NA 1,73 6,45 43,3 1760 9,52 26/01/16

II-WL-T-1 1 0,703 NA 2,05 9,83 10 NA 0,574 NA 1,97 9,02 35,8 66 11,95 3/11/15

II-WL-T-2 2 0,661 NA 2,09 10,10 10 NA 0,519 NA 1,95 8,70 17,0 116 12,94 10/11/15

II-WL-T-4 4 0,342 NA 1,94 9,68 10 NA 0,381 NA 1,85 7,67 41,6 906 12,49 24/11/15

II-WL-T-6 6 0,340 NA 1,92 9,95 8 NA 0,342 NA 1,66 7,04 40,6 1403 11,52 8/12/15

II-WL-T-8 8 0,498 NA 1,80 9,75 10 NA 0,575 NA 1,60 6,74 45,4 1756 11,26 22/12/15

II-WL-T-12 13 0,352 NA 1,88 9,81 10 NA 0,340 NA 1,46 5,37 42,4 3458 10,01 26/01/16

II-WL-C-1 1 0,361 NA 1,93 9,82 10 NA 0,422 NA 1,80 9,07 27,1 0 11,95 3/11/15

II-WL-C-2 2 0,477 NA 2,09 9,67 10 NA 0,511 NA 1,90 8,18 17,3 58 12,94 10/11/15

II-WL-C-4 4 0,425 NA 1,94 10,16 9 NA 0,406 NA 1,61 8,18 44,9 728 12,49 24/11/15

II-WL-C-6 6 0,525 NA 1,94 9,79 8 NA 0,330 NA 1,64 7,05 17,3 1074 11,52 8/12/15

II-WL-C-8 8 0,378 NA 1,81 9,91 10 NA 0,407 NA 1,55 7,46 19,0 1004 11,26 22/12/15

II-WL-C-12 13 0,503 NA 1,95 9,99 9 NA 0,500 NA 1,71 4,91 49,3 2188 10,01 26/01/16

II-MP-N-1 1 NA 0,713 2,09 9,90 NA 9 NA 0,636 1,90 8,86 38,7 44 11,54 3/11/15

II-MP-N-2 2 NA 0,706 1,86 9,86 NA 10 NA 0,760 1,66 8,02 30,4 73 12,37 10/11/15

II-MP-N-4 4 NA 0,645 1,87 10,03 NA 8 NA 0,676 1,68 7,60 52,8 1061 11,98 24/11/15

II-MP-N-6 6 NA 0,550 1,86 9,83 NA 10 NA 0,617 1,62 6,82 37,7 1735 10,99 8/12/15

II-MP-N-8 8 NA 1,263 1,78 9,92 NA 10 NA 1,095 1,51 5,80 53,0 2226 10,71 22/12/15

II-MP-N-12 13 NA 0,536 1,91 9,74 NA 10 NA 0,587 1,51 5,45 55,3 3065 9,52 26/01/16

II-MP-M-1 1 NA 0,574 2,08 9,74 NA 10 NA 0,560 1,94 9,02 25,0 0 11,54 3/11/15

II-MP-M-2 2 NA 0,568 1,97 9,93 NA 9 NA 0,514 1,87 8,44 19,9 42 12,37 10/11/15

II-MP-M-4 4 NA 0,916 2,01 9,85 NA 10 NA 0,955 1,81 7,75 45,3 808 11,98 24/11/15

II-MP-M-6 6 NA 0,625 1,96 9,83 NA 10 NA 0,695 1,73 6,59 35,9 1197 10,99 8/12/15

II-MP-M-8 8 NA 0,874 1,84 10,04 NA 10 NA 0,909 1,65 6,55 47,6 1193 10,71 22/12/15

45

Table 3 continued

CODE

Weeks in the field


levels

Average Temperature

(°C) DATE


WL Total


Soil (%)

Total rainfall (ml)

II-MP-M-12 13 NA 0,340 1,98 10,15 NA 10 NA 0,374 1,84 6,19 43,2 2591 9,52 26/01/16

II-MP-T-1 1 NA 0,433 1,87 9,90 NA 10 NA 0,438 1,67 9,09 33,7 48 11,95 3/11/15

II-MP-T-2 2 NA 0,705 1,91 9,88 NA 10 NA 0,606 1,75 8,18 45,0 143 12,94 10/11/15

II-MP-T-4 4 NA 0,564 1,89 9,96 NA 10 NA 0,597 1,75 7,58 48,9 1113 12,49 24/11/15

II-MP-T-6 6 NA 0,880 1,96 10,08 NA 8 NA 0,772 1,66 6,62 33,5 1351 11,52 8/12/15

II-MP-T-8 8 NA 0,541 2,01 9,89 NA 8 NA 0,576 1,79 6,59 33,5 1736 11,26 22/12/15

II-MP-T-12 13 NA 0,646 2,02 10,11 NA 10 NA 0,695 1,44 4,49 46,1 3458 10,01 26/01/16

II-MP-C-1 1 NA 0,904 1,91 10,00 NA 10 NA 0,750 1,78 9,00 19,0 0 11,95 3/11/15

II-MP-C-2 2 NA 0,681 1,94 10,02 NA 10 NA 0,710 1,75 8,60 36,0 83 12,94 10/11/15

II-MP-C-4 4 NA 0,755 2,13 9,85 NA 9 NA 0,520 1,86 7,76 34,8 728 12,49 24/11/15

II-MP-C-6 6 NA 0,770 1,88 9,79 NA 9 NA 0,608 1,59 7,09 26,1 1024 11,52 8/12/15

II-MP-C-8 8 NA 1,285 2,00 10,04 NA 10 NA 1,379 1,47 5,92 39,2 1091 11,26 22/12/15

II-MP-C-12 13 NA 1,182 1,85 9,75 NA 6 NA 1,016 1,39 4,67 37,0 1937 10,01 26/01/16

II-MX-N-1 1 0,185 0,184 1,94 9,84 5 5 0,220 0,206 1,83 8,94 33,6 44 11,54 3/11/15

II-MX-N-2 2 0,221 0,500 1,90 10,01 5 5 0,265 0,359 1,80 8,44 43,1 73 12,37 10/11/15

II-MX-N-4 4 0,323 0,229 1,95 9,71 5 5 0,194 0,271 1,73 7,06 51,4 1093 11,98 24/11/15

II-MX-N-6 6 0,207 0,193 1,99 9,96 4 5 0,170 0,232 1,49 7,02 41,9 1529 10,99 8/12/15

II-MX-N-8 8 0,292 0,578 2,05 10,03 2 2 0,129 0,190 1,59 6,73 47,3 1959 10,71 22/12/15

II-MX-N-12 13 0,146 0,865 2,05 10,00 5 5 0,180 0,709 1,63 5,61 47,8 3302 9,52 26/01/16

II-MX-M-1 1 0,221 0,675 2,05 9,81 4 5 0,198 0,683 1,87 8,98 27,4 0 11,54 3/11/15

II-MX-M-2 2 0,180 0,532 1,96 10,14 5 5 0,191 0,560 1,82 8,54 27,0 48 12,37 10/11/15

II-MX-M-4 4 0,280 0,530 2,05 9,98 5 5 0,300 0,575 1,84 7,78 37,1 1027 11,98 24/11/15

II-MX-M-6 6 0,381 0,351 2,11 9,83 5 5 0,420 0,391 2,02 6,67 40,9 1152 10,99 8/12/15

II-MX-M-8 8 0,392 0,468 1,90 10,19 5 5 0,236 0,497 1,62 6,68 35,7 1280 10,71 22/12/15

II-MX-M-12 13 0,251 0,576 1,88 9,83 5 4 0,276 0,400 1,53 5,02 43,9 2591 9,52 26/01/16

II-MX-T-1 1 0,264 0,446 1,90 9,83 5 5 0,300 0,476 1,73 8,80 33,5 52 11,95 3/11/15

II-MX-T-2 2 0,260 0,455 1,99 10,00 5 5 0,294 0,285 1,82 8,38 29,2 100 12,94 10/11/15

II-MX-T-4 4 0,228 0,597 2,05 9,96 1 4 0,063 0,402 1,75 7,31 39,7 901 12,49 24/11/15

II-MX-T-6 6 0,279 0,180 1,96 9,89 5 5 0,306 0,188 1,59 6,92 39,4 1438 11,52 8/12/15

II-MX-T-8 8 0,343 0,538 1,93 9,98 5 5 0,379 0,350 1,55 6,91 54,4 1985 11,26 22/12/15

II-MX-T-12 13 0,155 0,328 1,94 9,78 5 5 0,184 0,348 1,40 6,29 44,8 2765 10,01 26/01/16

II-MX-C-1 1 0,290 0,431 1,98 9,86 5 5 0,312 0,246 1,86 9,00 20,7 0 11,95 3/11/15

II-MX-C-2 2 0,243 0,316 2,11 9,84 3 5 0,178 0,308 1,96 8,60 24,1 79 12,94 10/11/15

II-MX-C-4 4 0,180 0,320 1,95 10,12 4 5 0,128 0,329 1,71 7,78 26,8 705 12,49 24/11/15

II-MX-C-6 6 0,434 0,441 1,92 9,81 5 4 0,297 0,204 1,74 7,67 19,6 1138 11,52 8/12/15

II-MX-C-8 8 0,210 0,225 1,95 9,96 5 5 0,242 0,252 1,62 6,91 46,2 1169 11,26 22/12/15

II-MX-C-12 13 0,230 0,411 2,05 10,19 4 5 0,210 0,230 1,53 6,72 40,8 1937 10,01 26/01/16

III-CO-N-1 1 NA NA 1,93 10,12 NA NA NA NA 1,80 9,31 24,6 66 11,24 5/11/15


46

Table 3 continued

CODE

Weeks in the field


levels

Average Temperature

(°C) DATE


WL Total


Soil (%)

Total rainfall (ml)





III-CO-M-1 1 NA NA 1,99 10,00 NA NA NA NA 1,86 9,17 50,3 3 11,24 5/11/15






III-CO-T-1 1 NA NA 1,97 9,98 NA NA NA NA 1,88 9,07 39,4 79 11,67 5/11/15






III-CO-C-1 1 NA NA 1,98 10,03 NA NA NA NA 1,87 9,31 25,0 6 11,67 5/11/15






III-WL-N-1 1 0,281 NA 1,97 9,99 8 NA 0,250 NA 1,86 9,06 30,9 77 11,24 5/11/15

III-WL-N-2 2 0,352 NA 1,98 9,96 10 NA 0,366 NA 1,86 8,75 38,1 73 12,52 12/11/15

III-WL-N-4 4 0,335 NA 1,99 9,98 6 NA 0,205 NA 1,78 7,66 59,1 1054 11,63 26/11/15

III-WL-N-6 6 0,331 NA 2,08 10,06 5 NA 0,188 NA 1,71 7,14 46,9 1374 10,87 10/12/15

III-WL-N-8 8 0,272 NA 1,97 10,04 9 NA 0,265 NA 1,83 6,80 48,6 1894 10,68 24/12/15

III-WL-N-12 13 0,405 NA 2,00 9,95 8 NA 0,371 NA 1,59 5,91 54,1 3059 9,44 28/01/16

III-WL-M-1 1 0,393 NA 2,04 10,07 10 NA 0,399 NA 1,86 9,23 20,5 5 11,24 5/11/15

III-WL-M-2 2 0,314 NA 2,07 9,95 10 NA 0,320 NA 1,91 8,78 21,4 19 12,52 12/11/15

III-WL-M-4 4 0,420 NA 2,00 9,94 10 NA 0,420 NA 1,80 8,17 44,5 808 11,63 26/11/15

III-WL-M-6 6 0,610 NA 1,96 9,96 8 NA 0,511 NA 1,66 7,58 45,5 1098 10,87 10/12/15

III-WL-M-8 8 0,297 NA 1,93 10,06 7 NA 0,226 NA 1,60 7,46 46,4 1229 10,68 24/12/15

III-WL-M-12 13 0,473 NA 1,97 10,01 10 NA 0,514 NA 1,57 6,13 51,6 1800 9,44 28/01/16

III-WL-T-1 1 0,477 NA 1,98 10,07 9 NA 0,464 NA 1,84 9,15 36,4 53 11,67 5/11/15

III-WL-T-2 2 0,315 NA 1,95 10,00 7 NA 0,211 NA 1,78 8,72 35,2 85 13,09 12/11/15

III-WL-T-4 4 0,368 NA 1,96 10,05 7 NA 0,293 NA 1,76 8,06 45,3 1089 12,13 26/11/15

III-WL-T-6 6 0,476 NA 1,98 10,04 7 NA 0,306 NA 1,53 7,42 26,5 1526 11,39 10/12/15

III-WL-T-8 8 0,355 NA 1,96 10,03 9 NA 0,305 NA 1,58 7,37 53,1 2103 11,23 24/12/15

47

Table 3 continued

CODE

Weeks in the field


levels

Average Temperature

(°C) DATE


WL Total


Soil (%)

Total rainfall (ml)

III-WL-T-12 13 0,382 NA 2,05 10,00 9 NA 0,322 NA 1,70 5,98 49,5 3180 9,94 28/01/16

III-WL-C-1 1 0,338 NA 2,01 10,05 10 NA 0,353 NA 1,80 9,22 11,9 6 11,67 5/11/15

III-WL-C-2 2 0,304 NA 2,01 9,98 10 NA 0,325 NA 1,88 8,78 21,3 22 13,09 12/11/15

III-WL-C-4 4 0,376 NA 2,02 10,00 9 NA 0,283 NA 1,84 7,96 34,2 801 12,13 26/11/15

III-WL-C-6 6 0,310 NA 1,96 9,96 9 NA 0,316 NA 1,73 7,77 41,3 1041 11,39 10/12/15

III-WL-C-8 8 0,315 NA 2,01 10,02 9 NA 0,308 NA 1,69 7,78 34,5 1181 11,23 24/12/15

III-WL-C-12 13 0,375 NA 1,99 9,98 8 NA 0,351 NA 1,59 6,49 38,8 1960 9,94 28/01/16

III-MP-N-1 1 NA 1,007 2,02 10,07 NA 10 NA 0,869 1,86 9,10 27,0 45 11,24 5/11/15

III-MP-N-2 2 NA 0,591 1,99 10,03 NA 10 NA 0,657 1,84 8,44 45,2 93 12,52 12/11/15

III-MP-N-4 4 NA 1,165 2,01 9,98 NA 10 NA 1,079 1,77 7,37 40,6 1217 11,63 26/11/15

III-MP-N-6 6 NA 0,456 1,94 10,04 NA 10 NA 0,483 1,87 6,97 40,6 1580 10,87 10/12/15

III-MP-N-8 8 NA 0,690 1,99 9,97 NA 10 NA 0,739 1,67 6,13 49,9 1894 10,68 24/12/15

III-MP-N-12 13 NA 0,600 2,01 9,98 NA 10 NA 0,600 1,57 6,99 52,2 2733 9,44 28/01/16

III-MP-M-1 1 NA 0,552 2,08 10,04 NA 10 NA 0,527 1,94 9,01 25,8 13 11,24 5/11/15

III-MP-M-2 2 NA 0,523 2,01 9,95 NA 10 NA 0,525 1,90 8,63 25,0 42 12,52 12/11/15

III-MP-M-4 4 NA 0,896 2,01 9,96 NA 10 NA 0,880 1,80 7,73 28,8 877 11,63 26/11/15

III-MP-M-6 6 NA 0,737 1,91 10,07 NA 10 NA 0,786 1,56 7,13 33,8 914 10,87 10/12/15

III-MP-M-8 8 NA 1,326 2,04 10,04 NA 10 NA 1,407 1,60 6,03 40,6 981 10,68 24/12/15

III-MP-M-12 13 NA 0,816 1,96 10,08 NA 10 NA 0,639 1,57 6,14 58,4 2125 9,44 28/01/16

III-MP-T-1 1 NA 0,741 1,98 10,03 NA 10 NA 0,712 1,86 9,06 25,1 58 11,67 5/11/15

III-MP-T-2 2 NA 0,766 1,96 9,94 NA 10 NA 0,804 1,80 8,45 28,1 132 13,09 12/11/15

III-MP-T-4 4 NA 0,962 2,04 10,06 NA 10 NA 0,784 1,78 8,02 45,6 1036 12,13 26/11/15

III-MP-T-6 6 NA 0,586 2,01 10,01 NA 10 NA 0,587 1,67 7,05 42,2 1526 11,39 10/12/15

III-MP-T-8 8 NA 0,889 1,95 9,97 NA 10 NA 0,701 1,67 6,64 45,0 1991 11,23 24/12/15

III-MP-T-12 13 NA 0,736 2,00 9,98 NA 10 NA 0,730 1,54 5,68 44,5 1736 9,94 28/01/16

III-MP-C-1 1 NA 0,728 2,05 10,04 NA 10 NA 0,516 1,90 9,13 38,9 14 11,67 5/11/15

III-MP-C-2 2 NA 0,858 2,03 10,01 NA 10 NA 0,669 1,82 8,50 39,7 83 13,09 12/11/15

III-MP-C-4 4 NA 0,562 1,96 10,02 NA 10 NA 0,524 1,71 7,87 16,6 819 12,13 26/11/15

III-MP-C-6 6 NA 0,641 1,96 10,02 NA 9 NA 0,584 1,67 7,12 17,8 1096 11,39 10/12/15

III-MP-C-8 8 NA 0,916 1,97 10,08 NA 9 NA 0,682 1,61 6,53 20,5 1169 11,23 24/12/15

III-MP-C-12 13 NA 0,926 1,97 10,02 NA 10 NA 0,929 1,78 5,99 44,3 1865 9,94 28/01/16

III-MX-N-1 1 0,230 0,235 1,98 10,01 5 5 0,243 0,256 1,82 9,10 33,0 54 11,24 5/11/15

III-MX-N-2 2 0,186 0,238 1,96 10,00 1 1 0,027 0,042 1,85 8,71 46,9 98 12,52 12/11/15

III-MX-N-4 4 0,188 0,227 1,98 10,09 5 5 0,199 0,247 1,90 7,52 37,4 1213 11,63 26/11/15

III-MX-N-6 6 0,154 0,170 1,97 9,98 5 5 0,157 0,191 1,61 7,04 53,1 1580 10,87 10/12/15

III-MX-N-8 8 0,168 0,250 2,03 9,98 3 5 0,090 0,265 1,77 7,08 45,8 2117 10,68 24/12/15

III-MX-N-12 13 0,217 0,229 1,96 9,99 5 5 0,221 0,209 1,56 5,40 56,0 3291 9,44 28/01/16

III-MX-M-1 1 0,135 0,175 2,00 10,06 5 5 0,146 0,188 1,88 9,07 19,6 0 11,24 5/11/15

III-MX-M-2 2 0,150 0,184 1,98 10,06 5 5 0,176 0,207 1,84 8,75 23,9 63 12,52 12/11/15

48

Table 3 continued

CODE

Weeks in the field


levels

Average Temperature

(°C) DATE


WL Total


Soil (%)

Total rainfall (ml)

III-MX-M-4 4 0,157 0,203 1,98 10,02 5 5 0,155 0,216 1,75 7,86 41,2 903 11,63 26/11/15

III-MX-M-6 6 0,126 0,264 1,99 10,02 3 5 0,098 0,280 1,65 7,22 32,4 1197 10,87 10/12/15

III-MX-M-8 8 0,163 0,237 1,98 10,00 5 5 0,188 0,280 1,69 6,67 44,9 1280 10,68 24/12/15

III-MX-M-12 13 0,183 0,223 2,00 10,01 4 5 0,162 0,232 1,66 6,41 46,9 2351 9,44 28/01/16

III-MX-T-1 1 0,201 0,456 2,01 10,00 4 5 0,173 0,478 1,86 8,99 42,6 79 11,67 5/11/15

III-MX-T-2 2 0,181 0,188 2,04 9,98 4 5 0,163 0,201 1,86 8,59 39,0 119 13,09 12/11/15

III-MX-T-4 4 0,243 0,259 2,00 10,04 4 5 0,194 0,290 1,73 7,64 54,9 1123 12,13 26/11/15

III-MX-T-6 6 0,193 0,318 1,98 9,98 5 3 0,255 0,291 1,73 7,00 43,7 1463 11,23 10/12/15

III-MX-T-8 8 0,141 0,487 2,01 9,97 5 5 0,178 0,514 1,69 7,09 35,0 1756 9,94 24/12/15

III-MX-T-12 13 0,180 0,333 2,03 10,00 5 5 0,188 0,369 1,64 6,41 49,5 3180 11,67 28/01/16

III-MX-C-1 1 0,201 0,411 2,02 10,02 5 5 0,226 0,446 1,90 8,92 19,9 0 13,09 5/11/15

III-MX-C-2 2 0,153 0,279 1,96 9,97 4 5 0,130 0,248 1,78 8,46 16,8 10 12,13 12/11/15

III-MX-C-4 4 0,202 0,386 2,03 9,96 4 4 0,186 0,406 1,81 7,69 20,3 819 11,39 26/11/15

III-MX-C-6 6 0,179 0,590 2,00 10,02 5 5 0,192 0,646 1,71 7,24 26,0 1074 11,23 10/12/15

III-MX-C-8 8 0,161 0,522 1,97 9,99 4 5 0,155 0,561 1,66 7,06 40,4 1091 9,94 24/12/15

III-MX-C-12 13 0,133 0,567 1,95 10,02 5 5 0,149 0,608 1,58 5,64 21,9 1863 NA 28/01/16

Legend

CODE Replicate I First replicate

II Second replicate

III Third replicate

Population CO Control group

WL Woodlouse monoculture

MP Millipede monoculture

MX Mixed culture

Treatment N Natural conditions

M Moisture treatment

T Temperature treatment

C Combination treatment

Time Number of weeks in the field

Interactions between woodlice and millipedes for leaf...

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