Biotic modifiers, environmental modulation and species distribution models
Source: Journal of Biogeography, Volume 39, Number 12, 1 December 2012 , pp. 2179-2190(12)
The ability of species to modulate environmental conditions and resources has long been of interest. In the past three decades the impacts of these biotic modifiers have been investigated as ‘ecosystem engineers’, ‘niche constructors’, ‘facilitators’ and ‘keystone species’. This environmental modulation can vary spatially from extremely local to global, temporally from days to geological time, and taxonomically from a few to a very large number of species. Modulation impacts are pervasive and affect, inter alia, the climate, structural environments, disturbance rates, soils and the atmospheric chemical composition. Biotic modifiers may profoundly transform the projected environmental conditions, and consequently have a significant impact on the predicted occurrence of the focal species in species distribution models (SDMs). This applies especially when these models are projected into different geographical regions or into the future or the past, where these biotic modifiers may be absent, or other biotic modifiers may be present. We show that environmental modulation can be represented in SDMs as additional variables. In some instances it is possible to use the species (e.g. biotic modifiers) in order to reflect the modulation. This would apply particularly to cases where the effect is the result of a single or a small number of species (e.g. elephants transforming woodland to grassland). Where numerous species generate an effect (such as tree species making a forest, or grasses facilitating fire) that modulates the abiotic environment, the effect itself might be a better descriptor for the aggregated action of the numerous species. We refer to this ‘effect’ as the modulator. Much of the information required to incorporate environmental modulation effects in SDMs is already available from remote‐sensing data and vegetation models.
Document Type: Research Article
Affiliations: 1: Institute of Systematic Botany, University of Zurich, Zurich, CH 8008, Switzerland 2: Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON M5S 3B2, Canada 3: Institute for Complex Systems Simulation, University of Southampton, Southampton SO171BJ, UK 4: Community and Conservation Ecology, Centre for Ecological and Evolutionary Studies, University of Groningen, 9700 CC Groningen, The Netherlands 5: LOEWE Biodiversity and Climate Research Centre (BiK-F) and Senckenberg Gesellschaft für Naturforschung and Department of Physical Geography at Goethe University, 62325 Frankurt/Main, Germany 6: Helmholtz Centre for Environmental Research – UFZ, Department of Community Ecology, 06120 Halle, Germany 7: Biomathematics & Statistics Scotland, Edinburgh EH9 3JZ, UK 8: School of Biological and Biomedical Sciences, and Institute of Hazard, Risk and Resilience, Durham University, Durham DH1 3LE, UK 9: Helmholtz Centre for Environmental Research – UFZ, Department of Ecological Modelling, 04318 Leipzig, Germany
Publication date: December 1, 2012