The potential distribution models of species are a good management resource for the management and control of biodiversity. But not everything is a model and results from the environmental variables of analysis. Any results from potential distribution models should go through a second phase of analysis to guarantee the viability of the species based on other cartographic factors, such as the geometry of the areas and the way in which they are distributed.
As a general rule, models of potential distribution of species make use of environmental variables that offer an attraction to the species or represent a fundamental resource for its reproduction, shelter and feeding. Far from considering only these biological needs, species also require other factors linked to geometric analysis and proximity analysis. It will be of no use to have the biggest hotspot of territorial aptitude for your species if it does not have a sufficient surface for its reproduction, the area is subject to pressures or if the species does not have the possibility of moving around the territory due to the presence of barriers.
Additional cartographic analyses to be considered in the potential species distribution maps can focus on the level of isolation of the patches, their morphology and the capacity of biological connection between them. Some aspects to be incorporated in the results of an initial model can be based on:
- Quantification of the surface viability of the patches
- Adequate morphology for the championship areas minimizing the edge effect
- Level of fragmentation of the championship zone
- Availability of refuge habitats and dispersal corridors
- Evaluation of the location of specific areas linked to biological phases (mating, nesting, migration)
- Analysis of territorial barriers
Under these factors, there are tools based on analysis of landscape units and ecological connectivity that can help profile and locate more precisely the potential areas of distribution, assess the level of isolation and optimize the distribution of territorial areas used by the species to fulfill parts of its biological cycle.
MORPHOLOGY
All species require minimum land area values to survive. Having surface values linked to the championship areas will help you to segment the territory to define minimum work units by projecting hierarchical surfaces and identify tesserae that allow the survival, reproduction and feeding of individuals. Geometry tools, reclassification or the traditional map algebra of any desktop GIS can help you quantify and delimit these areas.
FRAGMENTATION
It will not help you to have optimal areas if the territory is divided up or covered by linear infrastructures that fragment the territory and increase the edge effect of the habitats. A relationship between patch areas and perimeters can give us a picture of the degree of fragmentation of the distribution areas and exposure to predation or adverse agents outside the boundaries of the tesserae.
Tools such as Fragstats, Landscape Ecology Statistics or FragScape are some of the options available for analysing the way in which patches are distributed territorially.
CONNECTIVITY OF SPACES
Tools based on ecological corridors can evaluate potential paths between championship areas and identify the places at greatest risk of isolation. Tools such as Corridor Designer, CircuitScape or Linkage Mapper can warn you of these potential paths between championship zones..
BARRIERS
Any territorial barriers that hinder the movement of the species will result in individuals being relegated without allowing the results of potential distribution models to be adequately reflected. Evaluating natural or anthropogenic linear infrastructures between distribution areas or analyzing bottlenecks by evaluating territorial friction maps are ways of locating barriers and hostile environments.
LOCATION AND DISTRIBUTION OF KEY ECOSYSTEMS
Some species tend to return to certain territorial areas to perform some vital function of their life cycle. Migrating to reproduce in the places from which it originally came can be a clear example. Considering the proximity of these places with the help of Conefor and spatial proximity tools, or evaluating a migration corridor may be some of the tools available.
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