Landscape structure and species life history effects on
abundance-occupancy relationships
Abstract
More widespread species tend to be more locally abundant, both for the
population dynamics of a single species across a network of habitat
patches (intraspecific) and for many species sampled at a single point
in time (interspecific). These abundance-occupancy relationships are
fairly well-supported in observational studies, but the underlying
factors driving them are less clear. For instance, variation in
demographic rates, dispersal, and spatial habitat network structure
could all influence resulting abundance-occupancy relationships. We
propose a simple simulation model to explore intraspecific and
interspecific relationships. We create spatial habitat networks of
variable size and dispersal connectivity, and simulate population
dynamics across spatial networks by starting from entirely neutral
communities, then systematically incorporating complexity in the form of
(co)variation in species demographic rates and dispersal processes. We
find that intraspecific abundance-occupancy relationships are quite weak
and unaffected by the incorporation of demographic or dispersal rate
variation or network structure. However, interspecific
abundance-occupancy relationships were quite strong and sensitive to the
spatial network structure and (co)variation in demographic and dispersal
rates. This identifies a clear difference between the two forms of the
relationship, as intraspecific abundance-occupancy relationships rely on
temporal variation in environmental conditions independent of species
trait variation, while interspecific abundance-occupancy relationships
require species trait differences. Together, we provide a clear,
spatially-explicit framework to explore the potential drivers of
abundance-occupancy relationships, with potential extensions to many
other macroecological relationships.