Local Facilitation May Cause Tipping Points on a Landscape Level Preceded by Early-Warning Indicators
Authored by Marten Scheffer, Chi Xu, Egbert van Nes, Milena Holmgren, Sonia Kefi
Date Published: 2015
DOI: 10.1086/682674
Sponsors:
European Union
Chinese National Natural Science Foundation
Platforms:
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Model Documentation:
Other Narrative
Mathematical description
Model Code URLs:
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Abstract
Positive biotic interactions play a significant role in shaping
ecological communities. We used an individual-based model to demonstrate
that plant facilitation on a microscale may cause ecosystem shifts on a
landscape scale that can be announced by generic early-warning
indicators. Recruitment of woody plants in harsh environments such as
drylands often depends on nurse plants that ameliorate stressful
conditions and facilitate the establishment of seedlings under their
canopy. We found that these facilitative interactions may cause a
treeless and a woodland state to be alternative stable states on a
landscape scale if nurse plant effects are strong and if the environment
is harsh enough to make facilitation necessary for seedling survival. A
corollary is that under such conditions environmental change can bring
drylands to tipping points for woody plant encroachment or woodland
collapse. We show that the proximity of tipping points may be indicated
by slowness of recovery of woody vegetation cover from small
perturbations as well as by elevated temporal and spatial
autocorrelation and variance. These signs are known to be indicators of
critical slowing down. This is the first demonstration that the systemic
phenomena of tipping points, announced by critical slowing down as a
warning signal, may plausibly arise from microscale individual
interactions, such as plant facilitation.
Tags
Critical
transitions
Arid ecosystems
Positive interactions
Tropical forest
Plant succession
Tree seedling establishment
Spatial vegetation patterns
Catastrophic shifts
Abandoned pasture
Eastern
amazonia