Distribution Models Biology Lab Report

Distribution Models Biology Lab Report
1. Learn what are shapefiles, pointfiles, and gridfiles/rasters
2. Discuss the relationship between environments and species’ distributions
3. Build a species distribution model based on locality and environmental data
4. Explore distribution changes with changing environments (in both time and space)
Key concepts and calculations:
1. Species distribution model (SDM): an interpolation of habitat suitability for a species given
occurrence information and associated environmental data
2. BAM diagram: the conceptual framework of Biotic, Abiotic, and Movement (or Mobility, or
Migration) factors that determine where a species can exist and where it does exist
3. Geographic range vs. potential distribution
Activities during lab period:
1. Instructor-led Wallace tutorial, modeling distributions in a conservation context
a. Modeling the distribution & habitat suitability of the polar bear (Ursus maritimus)
b. Temporal projection – examining distribution/suitability at a different time
2. Create a model, using Wallace, for a wildlife species of public health importance
a. Possibilities include those species potentially linked to the current coronavirus pandemic
– such as the Chinese rufous horseshoe bat (Rhinolophus sinicus) or a member of the
pangolin family (Manis javanica, Manis crassicaudata, Manis pentadactyla) – or one of
three bat species acting as reservoirs for Ebola virus (Hypsignathus monstrosus, Epomops
franqueti, or Myonycteris torquata)
Distribution Models Biology Lab Report
b. Alternatively, propose a species of your own choosing and model its environmental
niche/habitat suitability
c. Project geographically (across space) and temporally (across time) and discuss
Background:
Geographic ranges of species are influenced by three main factors. First, they
are a reflection of the abiotic (environmental) conditions that are suitable for a
species’ persistence (“A” in figure to the right). Second, biotic interactions can
limit the areas where species can be present; for example, strong competition
may exclude a focal species (“B” in figure). Finally, even if abiotic and biotic
conditions are suitable, a species must be able to access a region, or migrate to
it, for the species to be present (“M” in figure).
Lab exercises:
Wallace is a Graphical User Interface (also known as GUI, think “point-and-click”) application for
ecological modeling programmed in the computer language R. Its current version focuses on building,
evaluating, and visualizing models of species niches and distributions. We will refer to these models as
Species Distribution Models (SDMs) without explaining them at length here. Know that there is
continuous debate about what these models actually show the user, but you can think of them as
hypotheses of the geographical distribution of a species based on environmental conditions of the areas
where the species is known to occur. As you read through sections of the online app (called components
and modules), you will be pointed to some sources of detailed info for reference.