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Challenges of scale when examining plant-interactions in arid ecosystems: micro, local, & regional
Alessandro Filazzola
ORHow I learned to stop worrying and trust the rain
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mechanisms of positive plant-interactions
Filazzola & Lortie 2014
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Gómez Aparicio,‐ et al. 2005
shrubs ameliorate abiotic stress
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Gómez Aparicio,‐ et al. 2005
shrubs modify soil nutrients
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effects of positive interactions globally
He et al. 2013
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how does scale relate to plant interactions?
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north south
soil moisturelight
temperature
soil nutrientsherbivory reduction
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Hoffman et al. 2013
microscale variation in deserts
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rocks can out perform shrubs as facilitators
Peters et al. 2008
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Pescador et al. 2014
effect of a facilitator are not dichotomous
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Schlesinger et al. 1996
compare nutrients with distance from shrub
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Schlesinger et al. 1996
nitrogen is spatially correlated
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Franco & Nobel 1989
compare seeds with distance from shrub
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Filazzola et al., 2016
mechanisms are scale specific
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sampling considerations for micro gradientsConsider topographical variation (e.g. soil depressions, rocks)
Include spatial associations of plants, such as with shrubs
Include different aspects (e.g. cardinal directions)
Sample varying distances from dominant shrub
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Keddy 1992
community composition based on filters
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Cavieres et al. 2002
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elevation as a local scale gradient
Panoche 1130m 960m 730m
Mojave DesertSan Joaquin Valley
Lortie et al. 2016
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hill aspect as a local scale gradient
Lortie et al. 2016
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Chaenactis fremontii
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RII 0
-1
+1
local gradients alter microscale association among plants
-1+1
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similar gradients, different outcomes
Lortie et al. 2016
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Michalet et al. 2006
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local gradient
mic
rosc
ale
grad
ient
local gradients alter microscale plant interactions
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sampling considerations for local gradientsConsider landscape topography
Include the full length of the gradient
Multiple points along a gradient
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the regional scale
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positive interactions increase community richness
Cavieres and Badano 2009
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Scale determines plant-interactions
Callaway et al. 2002
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Sotomayor et al. 2016
beneficiaries associate with benefactors
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Sotomayor et al. 2016
beneficiaries associate with benefactors
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parallels among spatial scales
micro local regional
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parallels among spatial scales
micro
local
regional
shrub open
west longitude
south slopenorth slope
east longitude
increasing evapotranspiration
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interactions among spatial scales
micro
local
regional
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spatial gradients as a response surface
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further considerations
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additional stressors change predictions
Crain et al. 2008
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additional stressors change predictions
Smit et al. 2009
No herbivoresWith herbivores
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most studies only examine one stressor
Filazzola & Lortie 2014
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species specificity changes predictions
Albert et al. 2010
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species specificity changes predictions
Maestre et al. 2009
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temporal effects alter plant interactions
Chesson et al. 2004
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temporal effects alter plant interactions
Miriti 2006
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Castro et al. 2002
microscale association for restoration
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Gomez-Aparicio 2009
microscale association for restoration
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Dominant-mediated distribution of invasives
Survival of experimentally planted seedlings of Taraxacum officinale within and outside Azorella monantha cushions at 3200 m a.s.l.
Cavieres et al. 2007
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invasive beneficiaries negative affect benefactors
Rodrıguez-Buritica & Miriti 2009
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loss of invasive and native species
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Positive plant-interactions support biodiversity across all spatial gradients
Rodriguez-Cabal et al. 2012
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Thank youDr. Chris LortieDr. Sapna SharmaDr. Bridget StutchburyDr. Michael WestphalDr. Diego SotomayorThe Ecoblender LabBLM: Central Coast Field OfficeDr. Richard MichaletDr. Jim AndreDr. Tasha Le DouxTejon Ranch Conservancy
filazzola.info
@alex_filazzola
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Discussion
1. How (or should we) include these micro- and local-scale gradients when conducting regional modelling?
2. What should field experiments focus on in terms of scale? Deep vs wide?
3. How do you know that you have surveyed the full length a gradient?
4. Controlling variables or measuring covariates?
5. Insights into other fields that utilize scale and further implications