Microhabitat amelioration and reduced competition among understorey plants as drivers of facilitation across environmental gradients: Towards a unifying framework

Santiago Soliveres, David J. Eldridge, Fernando T. Maestre, Matthew A Bowker, Matthew Tighe, Adrián Escudero

Research output: Contribution to journalArticle

89 Citations (Scopus)

Abstract

Studies of facilitative interactions as drivers of plant richness along environmental gradients often assume the existence of an overarching stress gradient that equally affects the performance of all the species in a given community. However, co-existing species differ in their ecophysiological adaptations, and do not experience the same stress level under particular environmental conditions. Moreover, these studies assume a unimodal relationship between richness and biomass, which is not as general as previously thought. We ignored these assumptions to assess changes in plant-plant interactions and their effect on local species richness across environmental gradients in semi-arid areas of Spain and Australia. We aimed to understand the relative importance of direct (microhabitat amelioration) and indirect (changes in the competitive relationships among the understorey species: niche segregation, competitive exclusion or intransitivity) mechanisms that might underlie the effects of nurse plants on local species richness. By jointly studying these direct and indirect mechanisms using a unifying framework, we found that nurse plants (trees, shrubs and tussock grasses) increased local richness not only by expanding the niche of neighbouring species but also by increasing niche segregation among them, though the latter was not important in all cases. The outcome of the competition-facilitation continuum varied depending on the study area, likely because the different types of stress gradient considered. When driven by both rainfall and temperature, or rainfall alone, the community-wide importance of nurse plants remained constant (Spanish sites), or showed a unimodal relationship along the gradient (Australian sites). This study expands our understanding of the relative roles of plant-plant interactions and environmental conditions as drivers of local species richness in semi-arid environments. The results can also be used to refine predictions about the response of plant communities to environmental change, and to clarify the relative importance of biotic interactions as drivers of such responses.

Original languageEnglish (US)
Pages (from-to)247-258
Number of pages12
JournalPerspectives in Plant Ecology, Evolution and Systematics
Volume13
Issue number4
DOIs
StatePublished - Nov 20 2011
Externally publishedYes

Fingerprint

facilitation
environmental gradient
microhabitat
microhabitats
understory
nurse plant
nurse plants
remediation
niche
niches
species richness
species diversity
environmental conditions
rain
rainfall
environmental factors
competitive exclusion
dry environmental conditions
arid environment
plant community

Keywords

  • Competitive exclusion model
  • Niche expansion
  • Niche segregation
  • Plant-plant interactions
  • Richness-biomass relationship
  • Stress-gradient hypothesis

ASJC Scopus subject areas

  • Plant Science
  • Ecology, Evolution, Behavior and Systematics

Cite this

Microhabitat amelioration and reduced competition among understorey plants as drivers of facilitation across environmental gradients : Towards a unifying framework. / Soliveres, Santiago; Eldridge, David J.; Maestre, Fernando T.; Bowker, Matthew A; Tighe, Matthew; Escudero, Adrián.

In: Perspectives in Plant Ecology, Evolution and Systematics, Vol. 13, No. 4, 20.11.2011, p. 247-258.

Research output: Contribution to journalArticle

@article{e10a46c48bc94fbf884b57af91f4c7c9,
title = "Microhabitat amelioration and reduced competition among understorey plants as drivers of facilitation across environmental gradients: Towards a unifying framework",
abstract = "Studies of facilitative interactions as drivers of plant richness along environmental gradients often assume the existence of an overarching stress gradient that equally affects the performance of all the species in a given community. However, co-existing species differ in their ecophysiological adaptations, and do not experience the same stress level under particular environmental conditions. Moreover, these studies assume a unimodal relationship between richness and biomass, which is not as general as previously thought. We ignored these assumptions to assess changes in plant-plant interactions and their effect on local species richness across environmental gradients in semi-arid areas of Spain and Australia. We aimed to understand the relative importance of direct (microhabitat amelioration) and indirect (changes in the competitive relationships among the understorey species: niche segregation, competitive exclusion or intransitivity) mechanisms that might underlie the effects of nurse plants on local species richness. By jointly studying these direct and indirect mechanisms using a unifying framework, we found that nurse plants (trees, shrubs and tussock grasses) increased local richness not only by expanding the niche of neighbouring species but also by increasing niche segregation among them, though the latter was not important in all cases. The outcome of the competition-facilitation continuum varied depending on the study area, likely because the different types of stress gradient considered. When driven by both rainfall and temperature, or rainfall alone, the community-wide importance of nurse plants remained constant (Spanish sites), or showed a unimodal relationship along the gradient (Australian sites). This study expands our understanding of the relative roles of plant-plant interactions and environmental conditions as drivers of local species richness in semi-arid environments. The results can also be used to refine predictions about the response of plant communities to environmental change, and to clarify the relative importance of biotic interactions as drivers of such responses.",
keywords = "Competitive exclusion model, Niche expansion, Niche segregation, Plant-plant interactions, Richness-biomass relationship, Stress-gradient hypothesis",
author = "Santiago Soliveres and Eldridge, {David J.} and Maestre, {Fernando T.} and Bowker, {Matthew A} and Matthew Tighe and Adri{\'a}n Escudero",
year = "2011",
month = "11",
day = "20",
doi = "10.1016/j.ppees.2011.06.001",
language = "English (US)",
volume = "13",
pages = "247--258",
journal = "Perspectives in Plant Ecology, Evolution and Systematics",
issn = "1433-8319",
publisher = "Urban und Fischer Verlag Jena",
number = "4",

}

TY - JOUR

T1 - Microhabitat amelioration and reduced competition among understorey plants as drivers of facilitation across environmental gradients

T2 - Towards a unifying framework

AU - Soliveres, Santiago

AU - Eldridge, David J.

AU - Maestre, Fernando T.

AU - Bowker, Matthew A

AU - Tighe, Matthew

AU - Escudero, Adrián

PY - 2011/11/20

Y1 - 2011/11/20

N2 - Studies of facilitative interactions as drivers of plant richness along environmental gradients often assume the existence of an overarching stress gradient that equally affects the performance of all the species in a given community. However, co-existing species differ in their ecophysiological adaptations, and do not experience the same stress level under particular environmental conditions. Moreover, these studies assume a unimodal relationship between richness and biomass, which is not as general as previously thought. We ignored these assumptions to assess changes in plant-plant interactions and their effect on local species richness across environmental gradients in semi-arid areas of Spain and Australia. We aimed to understand the relative importance of direct (microhabitat amelioration) and indirect (changes in the competitive relationships among the understorey species: niche segregation, competitive exclusion or intransitivity) mechanisms that might underlie the effects of nurse plants on local species richness. By jointly studying these direct and indirect mechanisms using a unifying framework, we found that nurse plants (trees, shrubs and tussock grasses) increased local richness not only by expanding the niche of neighbouring species but also by increasing niche segregation among them, though the latter was not important in all cases. The outcome of the competition-facilitation continuum varied depending on the study area, likely because the different types of stress gradient considered. When driven by both rainfall and temperature, or rainfall alone, the community-wide importance of nurse plants remained constant (Spanish sites), or showed a unimodal relationship along the gradient (Australian sites). This study expands our understanding of the relative roles of plant-plant interactions and environmental conditions as drivers of local species richness in semi-arid environments. The results can also be used to refine predictions about the response of plant communities to environmental change, and to clarify the relative importance of biotic interactions as drivers of such responses.

AB - Studies of facilitative interactions as drivers of plant richness along environmental gradients often assume the existence of an overarching stress gradient that equally affects the performance of all the species in a given community. However, co-existing species differ in their ecophysiological adaptations, and do not experience the same stress level under particular environmental conditions. Moreover, these studies assume a unimodal relationship between richness and biomass, which is not as general as previously thought. We ignored these assumptions to assess changes in plant-plant interactions and their effect on local species richness across environmental gradients in semi-arid areas of Spain and Australia. We aimed to understand the relative importance of direct (microhabitat amelioration) and indirect (changes in the competitive relationships among the understorey species: niche segregation, competitive exclusion or intransitivity) mechanisms that might underlie the effects of nurse plants on local species richness. By jointly studying these direct and indirect mechanisms using a unifying framework, we found that nurse plants (trees, shrubs and tussock grasses) increased local richness not only by expanding the niche of neighbouring species but also by increasing niche segregation among them, though the latter was not important in all cases. The outcome of the competition-facilitation continuum varied depending on the study area, likely because the different types of stress gradient considered. When driven by both rainfall and temperature, or rainfall alone, the community-wide importance of nurse plants remained constant (Spanish sites), or showed a unimodal relationship along the gradient (Australian sites). This study expands our understanding of the relative roles of plant-plant interactions and environmental conditions as drivers of local species richness in semi-arid environments. The results can also be used to refine predictions about the response of plant communities to environmental change, and to clarify the relative importance of biotic interactions as drivers of such responses.

KW - Competitive exclusion model

KW - Niche expansion

KW - Niche segregation

KW - Plant-plant interactions

KW - Richness-biomass relationship

KW - Stress-gradient hypothesis

UR - http://www.scopus.com/inward/record.url?scp=82455199246&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=82455199246&partnerID=8YFLogxK

U2 - 10.1016/j.ppees.2011.06.001

DO - 10.1016/j.ppees.2011.06.001

M3 - Article

AN - SCOPUS:82455199246

VL - 13

SP - 247

EP - 258

JO - Perspectives in Plant Ecology, Evolution and Systematics

JF - Perspectives in Plant Ecology, Evolution and Systematics

SN - 1433-8319

IS - 4

ER -