Publication Details
Category Text Publication
Reference Category Journals
DOI 10.1111/1365-2745.13070
Title (Primary) Contingent factors explain average divergence in functional composition over 88 years of old field succession
Author Clark, A.T.; Knops, J.M.H.; Tilman, D.
Source Titel Journal of Ecology
Year 2019
Department iDiv; PHYDIV
Volume 107
Issue 2
Page From 545
Page To 558
Language englisch
Data and Software links https://doi.org/10.6073/pasta/aa029df8f7a6091ea879ceb5c6673963
https://doi.org/10.6073/pasta/cdb18a7bb4b03178b0efabb95389e7b7
https://doi.org/10.6073/pasta/84614d63ec31f1ada6076dfe8c3a6aea
Supplements Supplement 1
Supplement 2
Supplement 3
Supplement 4
Supplement 5
Supplement 6
Supplement 7
Keywords environmental driver; grassland; interspecific competition; metacommunity; old field succession; plant community assembly; plant population and community dynamics
Abstract
  1. “Old fields” are ecosystems that have been previously managed and subsequently abandoned, usually from agricultural use. These systems are classic testing grounds for hypotheses about community assembly. However, old field succession can be difficult to predict: seemingly similar fields often diverge in terms of species composition and environmental conditions.
  2. Here, we test the relative roles of contingency and stochasticity in driving vegetative successional dynamics. We draw on three decades of surveys in 24 old fields at the Cedar Creek Ecosystem Science Reserve (Minnesota, USA), and focus on five drivers that are known to shape local plant communities: soil fertility, fire, climate, competition, and demography. These drivers can contribute to contingency when they act consistently across fields and years (e.g., soil nitrogen accumulation, experimental fire regimes, or average climate), or to stochasticity when their effects are variable (e.g., annual variations in weather, or colonization and mortality events).
  3. We proceed in two steps. First, we fit regressions estimating abundance, colonization, and mortality for eight major functional groups in relation to these five drivers. We then use these regressions to parameterize a series of metacommunity simulation models, and test whether observed levels of stochasticity and variation in the drivers are sufficient to explain successional divergence.
  4. All drivers were significantly associated with plant species abundances, colonization, and mortality. Contingent factors strongly altered predicted successional trajectories. However, replicate simulations with similar conditions followed similar successional trajectories, suggesting that stochastic processes did not lead to divergence. This robustness of successional dynamics may be explained by compensatory trade‐offs. For example, species that were abundant late in succession typically suffered from low colonization rates and high mortality rates early in succession.
  5. Synthesis. Average successional dynamics among old fields at Cedar Creek follow largely consistent trends. Though dynamics of individual fields vary, much of this variation can be explained by contingent factors. Stochastic processes appear not to be sufficiently strong to create divergent successional trajectories among fields with similar sets of drivers. Our results therefore suggest that divergence among successional trajectories in chronosequences may be the result of predictable contingent factors, rather than unpredictable stochastic fluctuations.
Persistent UFZ Identifier https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=21145
Clark, A.T., Knops, J.M.H., Tilman, D. (2019):
Contingent factors explain average divergence in functional composition over 88 years of old field succession
J. Ecol. 107 (2), 545 - 558 10.1111/1365-2745.13070