the future of gradient studies in examining plant-plant interactions for the next 100 years

wake up

@cjlortie

need

changing interactions in a changing world

snapshots

inspiration

Sonia Kefi

science

Lonnie Aarssen

teaching

Mad Max

art

imagination

connections: no cape required

Michalet et al. 2015

imagination is our job

connect hypotheses, places, people, species, & data

gradients

gradients & variation make me happy

really happy

my mom was convinced I was a spy, and my children think science is an adventure.

natural & environmental gradients are special

we live in a big world

scientists are relatively small

change is a BIG process not an event

we need solutions that compress large scales but nonetheless capture change as a process

digital analog

gradients as solution

shortcut concept undermines true value

collectively, we need to imagine novel uses for gradients to examine change

(any of our ideas)

theory

a gradient is the change in a suite of parameters on a surface as it moves through space or time

an ecological gradient is typically assumed within a study when a change in the organism(s) of interest varies as one changes position

necessary condition for an ecological gradient is, however, the directional change in the underlying variation in parameter(s)

point processes

scalar integration

superimposition

vectorization

Env

ironm

enta

l m

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(i)

(ii)

Env

ironm

enta

l m

easu

res

All

mea

sure

s

(iii)

(iv)

Spatial position

Net

gra

dien

t ef

fect

e

b environmental & biotic overlays

gradient assembly is a four-step process

extent of extraction therefore varies

the assumption that gradients can always be reduced to simple linear vectors can lead to propagation of errors

the scalar field of environmental data is variable, not consistent

degree of sorting error

environmental aenvironmental b

environmental measures do not necessarily move in concert within a given spatial context

countervailing gradients

two points in space do not necessarily constitute a gradient

positions are arbitrarily assigned to relatively high or low

blocking error

veiled gradients

a proportion of the potentially causal variation undetermined

McCoy 2002

collective errors are opportunities

3

gradients vary in diversity & length

1

compression

extent of compression conveys variation

gradients as hypothesis-testing tools by providing at least two dimensions of change

2

capture

replicated regression & response surfaces

specific responses to gradients by species or groups

3

shared start & finish lines but how you get there can vary

(n = 350)

compression & capture

contrasts & sensitivity analyses

progress

4 explicit themes capture ~ 40% research

1.2M peer-reviewed ecology publications

interactions 167k

biodiversity 102k

climate change 93k

gradients 81k

1.2 M ecology publications

taxa tested with gradients

insects 4k

animals 21k

microbes 0.8k

plants 32k

stress 5k

biodiversity 10k

climate change 6k

disturbance 6k

concepts tested with gradients

stress 93k

biodiversity 165k

climate change 129k

disturbance 138k

citations to concepts tested with gradients

bean counting is fun but flawed

but evidence from within studies is even better

stressed about stress

stress gradient hypothesis

Bertness & Callaway 1994

He at al. 2013

Global shifts towards positive species interactions with increasing environmental stress

novelty

contiguous vs unified disaggregated gradients

Oberle et al 2009SEMS

interaction loss vs species loss on gradients

Valiente-Banuet et al 2015delta

partitioning interactions

Michalet et al 2014effect sizes

novel human gradients

Kiers et al 2014anthropogenic drivers

& evolution

response surfaces on biotic gradients

Schob et al 2014Type III GLMMS

functional & phylogenetic gradients

Soliveres et al 2014SEMS

synoptic landscape gradients

Luck et al 2002gradient analyses

hyperspace evolution & diversity

Whittaker 1967gradient analyses

implications

species AND interactions change on gradients & collectively respond to global change

the change of change

stop blocking

low vs high blocks will only get us so far

contrast gradient lengths & drivers

local vs regional management

think tropically

open data, methods, & collaboration

same methods, different places

a master builder uses all the pieces