Do native intertidal burrowing crabs benefit from non-native Spartina alterniflora?

College of Environment and EcologyXiamen University, Fujian, China

Hanyu Meng2016/07/18

Our team~

Zhengjie LiWenwen Liu

Xiao Chang

Tianbai Chen

Yiqing Zheng

Dan Peng

Xincong Chen

Yihui Zhang

Advisor

IntroductionInvasive alien species can have serious ecological and economic impacts across the globe (Vilà et al. 2011).

During the establishment and further spread of invasive species in native ecosystem, the interactions between invasive species and native species will occur (Wan et al. 2011).

Invasive plants - Native animals

Spartina alterniflora Burrowing crabs

IntroductionS. alterniflora transforms open mudflats to tall, dense vegetation (Li et al. 2009, He et al. 2012), suppresses native marsh vegetation and associated animals (Li et al. 2009, Ma et al. 2011), and at low latitudes, invades mangrove habitat at higher in the intertidal zone (Zhang et al. 2012).

Zuo et al, 2012

Spartina

mangrove

From：Yihui Zhang

Phragmites

From：Bo Li

Spartina

Spartina

Zuo et al, 2012

>19°

Zuo et al, 2012

Spartina

mangrove

From：Yihui Zhang

Phragmites

From：Bo Li

Spartina

Spartina

IntroductionS. alterniflora transforms open mudflats to tall, dense vegetation (Li et al. 2009, He et al. 2012), suppresses native marsh vegetation and associated animals (Li et al. 2009, Ma et al. 2011), and at low latitudes, invades mangrove habitat at higher in the intertidal zone (Zhang et al. 2012).

Zuo et al, 2012

Spartina

mangrove

From：Yihui Zhang

Phragmites

From：Bo Li

Spartina

Spartina

Mangrove？

In salt marsh, Spartina could affect native crab distribution and diets, as well as provide compatible habitats for native crab(Wang et al, 2008; Qin et al, 2011).

Spartina

mangrove

From：Yihui Zhang

Habitat

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Mangrove Ecotone Spartina Mudflat

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(Li et al. 2014, Ecology)

In mangrove area, what’s the native crabs’ distribution with the invasion of exotic plant Spartina alterniflora?

Is there any difference of crab abundance between invasive Spartina and native mangrove?

Fig. 1 Location of the field site in mangrove area of ZhangjiangEstuary, Fujian Province, China.

August, 2013 August, 2014

Metaplax longipes

Parasesarma plicata

Sampling----pitfall traps (Li et al, 2014) Time: 2013 and 2014 Habitats: Mangrove, S.alterniflora, Unvegtated

mudflat Replicate traps:

n=15 (16 cm diameter, 25 cm deep, > 15 m apart within habitat)

The number of Parasesarma plicata and Metaplaxlongipes per trap every day for 3 consecutive days in Spring, Summer, Autumn and Winter.

Pitfall trap

Crab investigation

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2013 2014

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Parasesarma plicata MangroveSpartinaMudflat

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2013 2014

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Metaplax longipes

Fig. 2 Density of Parasesarmaplicata and Metaplax longipes in different habitats.

P. plicata was abundant in mangrove and Spartina marsh, while M. longipeswas abundant in unvegetated mudflat.

There was no significant difference of crab density between mangrove forest and Spartina marsh.

Uninvaded mudflat (2013)

Invaded by Spartina (2014)

Invasive plant affects the distribution of native crabs.

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Parasesarma plicata Metaplax longipes

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Uninvaded

Invaded

Fig. 3 Number of Parasesarma plicataand Metaplax longipes before and after S.alterniflora invading unvegetated mudflat within only one growing season.

Spartina removal experiment

Plots set time: May 2015 Treatment: Spartina;

Spartina removal; Unvegetated mudflat

Replicate traps: n=12 Size: 2*2 m Spartina removal

Fig. 4 Density of Parasesarmaplicata and Metaplax longipesin each treatment.

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2015/05 2016/05

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Parasesarma plicataSpartinaSpartina removal Mudflat

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2015/05 2016/05

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Metaplax longipes

Parasesarma plicata was abundant in mangrove and Spartina marsh, whileMetaplax longipes was abundant in unvegetated mudflat.

Spartina alterniflora could expand the intertidal distribution of native P. plicata but limit M. longipes’ distribution with S. alterniflora sharplyoccupying mudflats and displacing mangroves in the upper intertidal of Zhangjiang Estuary.

Conclusion

Spartina alterniflora

Parasesarma plicata

Metaplax longipes

+

─

Ongoing

What are the mechanisms that shaped the patterns of crabs’ distribution?

Additional studies will be conducted to disentangle the roles of the biotic (vegetation, predator, food source) and abiotic (light, temperature, salinity, sediment) factors on the habitat selection of these two crabs(Wang, 2008; Garside & Bishop 2014; He & Cui 2014).

Thank you!

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Spring Summer Autumn Winter2014

Parasesarma plicata MangroveEcotoneSpartinaMudflat

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Parasesarma plicata

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Spring Summer Autumn Winter2014

Metaplax longipes

B0 

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A  A 0.01.02.03.04.05.06.07.08.0

Spring Summer Autumn Winter

Individu

als/da

y/trap

2013

Metaplax longipes

Fig. 2 Number of Parasesarma plicata and Metaplax longipes in the four different habitats in Spring, Summer, Autumn and Winter 2013 and 2014.