esa 2016 filazzola - water limitation and consumer pressure in the desert
TRANSCRIPT
The effect of consumer pressure and abiotic stress on positive plant-interactions is mediated by droughtAlessandro Filazzola, Amanda Liczner, Michael Westphal, & Christopher J. Lortie
mechanisms of positive plant-interactions
Filazzola & Lortie 2014
Gómez Aparicio,‐ et al. 2005
shrubs ameliorate abiotic stress
shrubs reduce consumer pressure
Barbosa et al. 2009
insect abundance mammalian herbivory
most studies only examine one stressor
Filazzola & Lortie 2014
additional stressors change predictions
Smit et al. 2009
No herbivoresWith herbivores
additional stressors change predictions
Crain et al. 2008
RII 0
-1
+1
local gradients alter microscale association among plants
-1+1
Shrubs facilitate the annual community by concurrently reducing consumer pressure through associational resistance and ameliorate abiotic stress by increasing soil moisture
hypothesis and predictions
RII 0
-1
+1
-1+1
?
study site and extreme drought
2014 2016
1 - 6X 15
Design Water level
1 - 6X 5
Replication
Experimental design for 2014
Plots/sample size (N/n)
60 / 5
180 / 15
0/1X 15
Design Water level
0/1X 15
Replication
Experimental design for 2016
Plots/sample size (N/n)
60 / 15
60 / 15
E. californica ameliorates abiotic stress
Effect Biomass 2014 Biomass 2016
Soil moisture + +Microsite + +
Consumer pressure -Microsite * soil moisture
Microsite * consumer pressure +Microsite * consumer pressure *
soil moisture
E. californica reduces consumer pressure
facilitation had a greater effect than water addition or consumer pressure
an invasive species was facilitated more strongly than subordinates
RII 0
-1
+1
-1+1
E. californica facilitates regardless of soil moisture or consumer pressure
precipitation can increase phytophagous insects and attract non-resident herbivores
Patten 1998; Augustine & McNaughton 2006; Retzer & Miehe 2005
precipitation mediates mechanism of facilitation
drought above average rainfall
precipitation increases relative difference among shrub and open microsites
Augustine & McNaughton 2006
herbivory does not affect productivity when rainfall and soil fertility are high
species specificity changes predictions
Maestre et al. 2009
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
invasive beneficiaries negative affect benefactors
Rodrıguez-Buritica & Miriti 2009
loss of invasive and native species
implications
Interacting stressors alter predictions on positive plant interactions
Precipitation mediates stressors and mechanisms of facilitation in desert environments
The life strategy of beneficiary species relates to the facilitation effects
Shrubs in arid environments may be support non-native invasion
Thank youDr. Chris LortieDr. Sapna SharmaDr. Bridget StutchburyDr. Michael WestphalDr. Diego SotomayorThe Ecoblender LabBLM: Central Coast Field Office
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