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Community assembly in experimental Grasslands: Suitable environment or timely arrival?

Ejrnæs, Rasmus ; Bruun, Hans Henrik LU and Graae, Bente Jessen (2006) In Ecology 87(5). p.1225-1233
Abstract
It is hard to defend the view that biotic communities represent a simple and predictable response to the abiotic environment. Biota and the abiotic environment interact, and the environment of an individual certainly includes its neighbors and visitors in the community. The complexity of community assembly calls forth a quest for general principles, yet current results and theories on assembly rules differ widely.

Using a grassland microcosm as a model system, we manipulated fertility, disturbance by defoliation, soil/microclimate, and arrival order of species belonging to two groups differing in functional attributes. We analyzed the Outcome of community assembly dynamics in terms of species richness, invasibility, and species... (More)
It is hard to defend the view that biotic communities represent a simple and predictable response to the abiotic environment. Biota and the abiotic environment interact, and the environment of an individual certainly includes its neighbors and visitors in the community. The complexity of community assembly calls forth a quest for general principles, yet current results and theories on assembly rules differ widely.

Using a grassland microcosm as a model system, we manipulated fertility, disturbance by defoliation, soil/microclimate, and arrival order of species belonging to two groups differing in functional attributes. We analyzed the Outcome of community assembly dynamics in terms of species richness, invasibility, and species composition. The analyses revealed strong environmental control over species richness and invasibility. Species composition was mainly determined by the arrival order of species, indicating that historical contingency may change the outcome of community assembly. The probability for multiple equilibria appeared to increase with productivity and environmental stability. The importance of arrival order offers an explanation of the difficulties in predicting local occurrences of species in the field.



In our experiment, variation in fertility and disturbance was controlling colonization with predictable effects on emergent community properties such as species richness. The key mechanism is suggested to be asymmetric competition, and our results show that this mechanism is relatively insensitive to the species through which it works. While our analyses indicate a positive and significant correlation between richness and invasibility, the significance disappears after accounting for the effect of the environment.



The importance of arrival order (historical contingency) and environmental control supports the assumption of the unified neutral theory that different species within a trophic level can be considered functionally equivalent when it comes to community assembly. However, our results indicate that variation in asymmetric competition is the key factor determining the richness of the resulting communities, and this is far from neutral. (Less)
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author
; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Ecology
volume
87
issue
5
pages
1225 - 1233
publisher
Ecological Society of America
external identifiers
  • pmid:16761601
  • wos:000237552400018
  • scopus:33645127124
ISSN
0012-9658
DOI
10.1890/0012-9658(2006)87[1225:CAIEGS]2.0.CO;2
language
English
LU publication?
yes
additional info
The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Plant Ecology and Systematics (Closed 2011) (011004000)
id
71a851ad-8d15-4bb6-93a1-bf04008ac23f (old id 159583)
date added to LUP
2016-04-01 15:29:18
date last changed
2020-12-08 02:54:33
@article{71a851ad-8d15-4bb6-93a1-bf04008ac23f,
  abstract     = {It is hard to defend the view that biotic communities represent a simple and predictable response to the abiotic environment. Biota and the abiotic environment interact, and the environment of an individual certainly includes its neighbors and visitors in the community. The complexity of community assembly calls forth a quest for general principles, yet current results and theories on assembly rules differ widely. <br/><br>
Using a grassland microcosm as a model system, we manipulated fertility, disturbance by defoliation, soil/microclimate, and arrival order of species belonging to two groups differing in functional attributes. We analyzed the Outcome of community assembly dynamics in terms of species richness, invasibility, and species composition. The analyses revealed strong environmental control over species richness and invasibility. Species composition was mainly determined by the arrival order of species, indicating that historical contingency may change the outcome of community assembly. The probability for multiple equilibria appeared to increase with productivity and environmental stability. The importance of arrival order offers an explanation of the difficulties in predicting local occurrences of species in the field.<br/><br>
<br/><br>
In our experiment, variation in fertility and disturbance was controlling colonization with predictable effects on emergent community properties such as species richness. The key mechanism is suggested to be asymmetric competition, and our results show that this mechanism is relatively insensitive to the species through which it works. While our analyses indicate a positive and significant correlation between richness and invasibility, the significance disappears after accounting for the effect of the environment.<br/><br>
<br/><br>
The importance of arrival order (historical contingency) and environmental control supports the assumption of the unified neutral theory that different species within a trophic level can be considered functionally equivalent when it comes to community assembly. However, our results indicate that variation in asymmetric competition is the key factor determining the richness of the resulting communities, and this is far from neutral.},
  author       = {Ejrnæs, Rasmus and Bruun, Hans Henrik and Graae, Bente Jessen},
  issn         = {0012-9658},
  language     = {eng},
  number       = {5},
  pages        = {1225--1233},
  publisher    = {Ecological Society of America},
  series       = {Ecology},
  title        = {Community assembly in experimental Grasslands: Suitable environment or timely arrival?},
  url          = {http://dx.doi.org/10.1890/0012-9658(2006)87[1225:CAIEGS]2.0.CO;2},
  doi          = {10.1890/0012-9658(2006)87[1225:CAIEGS]2.0.CO;2},
  volume       = {87},
  year         = {2006},
}