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bioRxiv · 10.1101/034405

A Multiscale Framework for Deconstructing the Ecosystem Physical Template of High-Altitudes Lakes

Dragos G Zaharescu·Peter S Hooda·Carmen I Burghelea·Antonio Palanca-Soler
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Abstract

An ecosystem is generally sustained by a set of integrated physical elements forming a functional landscape unit - ecotope, which supplies nutrients, microclimate, and exchanges matter and energy with the wider environment. To better predict environmental change effects on ecosystems, particularly in critically sensitive regions such as high altitudes, it is imperative to recognise how their natural landscape heterogeneity works at different scales to shape habitats and sustain biotic communities prior to major changes.\n\nWe conducted a comprehensive survey of catchment physical, geological and ecological properties of 380 high altitude lakes and ponds in the axial Pyrenees at a variety of scales, in order to formulate and test an integrated model encompassing major flows and interactions that drive lake ecosystems.\n\nThree composite drivers encompassed most of the variability in lake catchment characteristics. In order of total percentage of variance explained they were: (i) hydrology/hydrodynamics-responsible for type and discharge of inlets/outlets, and for water body size; (ii) bedrock geomorphology, summarizing geology, slope and fractal order-all dictating vegetation cover of catchment slope and lake shore, and the presence of aquatic vegetation; and, (iii) topography, i.e. catchment formation type-driving lakes connectivity, and the presence of summer snow deposits. While driver (i) appeared to be local, (ii) and (iii) showed gradient changes along altitude and latitude. These three drivers differentiated several lake ecotopes based on their landscape similarities. The three-driver model was successfully tested on a riparian vegetation composition dataset, further illustrating the validity and fundamental nature of the concept.\n\nThe findings inform on the relative contribution of scale-dependent catchment physical elements to lake ecotope and ecosystem formation in high altitude lakes, which should be considered in any assessment of potentially major deleterious effects due to environmental/climate change.\n\n\n\nO_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=150 SRC=\"FIGDIR/small/034405_ufig1.gif\" ALT=\"Figure 1\">\nView larger version (85K):\norg.highwire.dtl.DTLVardef@4b92e5org.highwire.dtl.DTLVardef@198fca4org.highwire.dtl.DTLVardef@f2801dorg.highwire.dtl.DTLVardef@b8f588_HPS_FORMAT_FIGEXP M_FIG Lake Bassia at 2275m a.s.l. in the Pyrenees National Park, France, is one of the millions of remote high altitude lakes worldwide whose catchments are likely to experience severe effects due to climate change. Photo credit: Antonio Palanca-Soler.\n\nC_FIG

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Dragos G Zaharescu, Peter S Hooda, Carmen I Burghelea, Antonio Palanca-Soler. 2015-12-15. A Multiscale Framework for Deconstructing the Ecosystem Physical Template of High-Altitudes Lakes. https://doi.org/10.1101/034405

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