Local environmental context drives heterogeneity of early succession dynamics in alpine glacier forefields
Glacier forefields have long provided ecologists with a model to study patterns of plant succession following glacier retreat. While plant-survey-based approaches applied along chronosequences provide invaluable information on plant communities, the “space-for-time” approach assumes environmental un...
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| Published in: | Biogeosciences Vol. 20; no. 8; pp. 1649 - 1669 |
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| Main Authors: | , , , , , , , , , , , , , |
| Format: | Journal Article |
| Language: | English |
| Published: |
Katlenburg-Lindau
Copernicus GmbH
27-04-2023
European Geosciences Union Copernicus Publications |
| Subjects: | |
| Online Access: | Get full text |
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| Summary: | Glacier forefields have long provided ecologists with a model to study patterns of plant succession following glacier retreat. While plant-survey-based approaches applied along chronosequences provide invaluable information on plant communities, the “space-for-time” approach assumes
environmental uniformity and equal ecological potential across sites and does not account for spatial variability in initial site conditions. Remote
sensing provides a promising avenue for assessing plant colonization dynamics using a so-called “real-time” approach. Here, we combined 36 years
of Landsat imagery with extensive field sampling along chronosequences of deglaciation for eight glacier forefields in the southwestern European
Alps to investigate the heterogeneity of early plant succession dynamics. Based on the two complementary and independent approaches, we found strong
variability in the time lag between deglaciation and colonization by plants and in subsequent growth rates and in the composition of early plant
succession. All three parameters were highly dependent on the local environmental context, i.e., neighboring vegetation cover and energy
availability linked to temperature and snowmelt gradients. Potential geomorphological disturbance did not emerge as a strong predictor of succession
parameters, which is perhaps due to insufficient spatial resolution of predictor variables. Notably, the identity of pioneer plant species was highly
variable, and initial plant community composition had a much stronger influence on plant assemblages than elapsed time since deglaciation. Overall,
both approaches converged towards the conclusion that early plant succession is not stochastic as previous authors have suggested but rather
determined by local ecological context. We discuss the importance of scale in deciphering the complexity of plant succession in glacier forefields
and provide recommendations for improving botanical field surveys and using Landsat time series in glacier forefield systems. Our work demonstrates
complementarity between remote sensing and field-based approaches for both understanding and predicting future patterns of plant succession in
glacier forefields. |
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| ISSN: | 1726-4189 1726-4170 1726-4189 |
| DOI: | 10.5194/bg-20-1649-2023 |