Ecotypic differentiation in the competitive ability of beneficiary species

#TheSunTheMoonTheTruth

#TheShrubTheOpenTheTruth

@cjlortie

three things that cannot be hidden

the shrub or dominants

the open or non-canopy sites

the truth

extreme variation is an important opportunity

not at all deserts at the same of course

but many have significant selection processes & gradients

the methodology of shrub-open contrasts is a convenient experimental design tool but not necessarily the whole story

Pescador et al. 2014

Pescador et al. 2014

bivariate nearest-neighbor distance distributions

dart hits

Pescador et al. 2014

facilitation in the halo

dominants do have major relative influences in these systems

Filazzola & Lortie 2014

reasonable to assume that not only can there be different species associated with dominants but that

individuals within species can exhibit ecotypic differentiation

A test for ecotypic differentiation in the competitive ability of beneficiary species found under nurse-plants and in open sites in arid

systems

lortie, filazzola, lamarque, sotomayor

@cjlortie

teamwork & collaboration

http://bit.ly/ecotype

if you have a two-phase plant system, here is our approach to exploring the following:

(we want you to join the pack)

local adaptation phenotypic plasticity

ecotypic differentiation

pilot studies

step 1. seeds

Collect seeds from 5 different species of plants that are found both under shrubs in arid systems and in the open nearby. !A total of 2000 seeds per species is recommended as a minimum.

step 1I. patterns

Measure microenvironmental conditions & record plant densities for each species. !Use micro-loggers (we used pro v2s) & record at least a season of conditions under your shrub species and nearby in the open (non-canopied sites where your target species also occur).

step III. reciprocal condition trials (rcts)

petri dish or pot trials in growth chambers (reciprocal design)

modded the reciprocal common garden protocol

shrubopen

shrubopen

seedchambers

rcts on seeds to explore seed biology & germination

first set of pilot experiments: both SA & CA

a single density each species

a

b

c

d

e

a

b

c

d

e

under each setof conditions

SA species

Sotomayor et al. 2014

methodology generated differences

rcts on seeds

but what about the potential for different competitive abilities

Hypothesis. The microsite generated by dominants in two-phase communities leads to different competitive trait sets for the associated species because of different indirect interaction networks & reduced variation in microenvironmental conditions.

Predictions. (i) ndd (negative density dependence):Individuals from understory microsites respond more strongly & negatively to increasing seed densities.

!(ii) ce (competitive effect vs response):Individuals from understory microsites exert significantcompetitive effects on individuals from the open.

(iii) pp phenotypic plasticity: Individuals from open microsites respond more strongly to reciprocal conditions than shrub individuals.

cage matching: intraspecific seed density series

Lortie et al. 2009

understory open

#TheShrubTheOpenTheTruth

same initial protocol as first set of pilot experiments

density series each species

a

b

c

d

e

a

b

c

d

e

under each setof conditions

monoculture mixed

ndd

ce

pp

implications

density-dependent interactions between beneficiary species is an important concept in modeling community dynamics

rct is an effective protocol

implications

changes in apparent competition & facilitation are important factors that mediate the capacity for shrubs to buffer the loss of smaller plant

species within arid systems

impacts in arid ecosystems are not always pretty

experimentation at finer scales & collaboration globally needed

bonus slides: species identity is important

ndd

ce

pp