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Creators/Authors contains: "Van Cleemput, Elisa"

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  1. ; ; ( , Global Ecology and Biogeography)
    Abstract Aim

    The spectral variability hypothesis (SVH) predicts that spectral diversity, defined as the variability of radiation reflected from vegetation, increases with biodiversity. While confirmation of this hypothesis would pave the path for use of remote sensing to monitor biodiversity, support in herbaceous ecosystems is mixed. Methodological aspects related to scale have been the predominant explanation for the mixed support, yet biological characteristics that vary among herbaceous systems may also affect the strength of the relationship. Therefore, we examined the influence of three biological characteristics on the relationship between spectral and taxonomic diversity: vegetation density, spatial species turnover and invasion by non‐native species. We aimed to understand when and why spectral diversity may serve as an indicator of taxonomic diversity and be useful for monitoring.

     Location

    Continental U.S.A.

     Time Period

    Peak greenness in 2017.

     Major Taxa Studied

    Grassland and herbaceous ecosystems.

     Methods

    For nine herbaceous sites in the National Ecological Observatory Network, we calculated taxonomic diversity from field surveys of 20 m × 20 m plots and derived spectral diversity for those same plots from airborne hyperspectral imagery with a spatial resolution of 1 m. The strength of the taxonomic diversity–spectral diversity relationship at each site was subsequently assessed against measurements of vegetation density, spatial species turnover and invasion.

     Results

    We found a significant relationship between taxonomic and spectral diversity at some, but not all, sites. Spectral diversity was more strongly related to taxonomic diversity in sites with high species turnover and low invasion, but vegetation density had no effect on the relationship.

     Main Conclusions

    Using spectral diversity as a proxy for taxonomic diversity in grasslands is possible in some circumstances but should not just be assumed based on the SVH. It is important to understand the biological characteristics of a community prior to considering spectral diversity to monitor taxonomic diversity.

     
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  2. ; ; ; ; ; ; ; ; ; ( , Journal of Ecology)
    Abstract

    Fine‐scale microclimate variation due to complex topography can shape both current vegetation distributional patterns and how vegetation responds to changing climate. Topographic heterogeneity in mountains is hypothesized to mediate responses to regional climate change at the scale of metres. For alpine vegetation especially, the interplay between changing temperatures and topographically mediated variation in snow accumulation will determine the overall impact of climate change on vegetation dynamics.

    We combined 30 years of co‐located measurements of temperature, snow and alpine plant community composition in Colorado, USA, to investigate vegetation community trajectories across a snow depth gradient.

    Our analysis of long‐term trends in plant community composition revealed notable directional change in the alpine vegetation with warming temperatures. Furthermore, community trajectories are divergent across the snow depth gradient, with exposed parts of the landscape that experience little snow accumulation shifting towards stress‐tolerant, cold‐ and drought‐adapted communities, while snowier areas shifted towards more warm‐adapted communities.

    Synthesis: Our findings demonstrate that fine‐scale topography can mediate both the magnitude and direction of vegetation responses to climate change. We documented notable shifts in plant community composition over a 30‐year period even though alpine vegetation is known for slow dynamics that often lag behind environmental change. These results suggest that the processes driving alpine plant population and community dynamics at this site are strong and highly heterogeneous across the complex topography that is characteristic of high‐elevation mountain systems.

     
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  3. ; ; ; ; ( , Restoration Ecology)

    Restoration ecologists devote considerable time and resources to understanding the role of functional traits in community assembly and ecosystem functioning. However, while functional traits show promise in supporting restoration practice in some circumstances, traits are not often explicitly considered by practitioners. Here we highlight four reasons that are preventing the use of traits in restoration, ranging from different restoration targets and frameworks to practical considerations around species selection, databases, plant stock availability, and measurement approaches. We provide actions that can be taken by researchers, practitioners, plant stock producers, and policy makers to better incorporate functional traits in restoration practice and show how traits can complement existing practices to achieve both traditional/taxonomic and functional restoration targets. We hope to guide critical partnerships, missing research, and immediate actions to leverage the value of traits at all stages in the restoration process.

     
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  4. ; ; ; ; ; ; ; ; ; ; et al ( , Global Change Biology)
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