| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| 1.87 MB | Adobe PDF |
Authors
Advisor(s)
Abstract(s)
Aim: Biological invasions are pervasive in freshwater ecosystems, often causing native
species to contract into areas that remain largely free from invasive species impacts.
Predicting the location of such ecological refuges is challenging, because they
are shaped by the habitat requirements of native and invasive species, their biotic
interactions, and the spatial and temporal invasion patterns. Here, we investigated
the spatial distribution and environmental drivers of refuges from invasion in river
systems, by considering biotic interactions in geostatistical models accounting for
stream network topology. We focused on Mediterranean amphibians negatively impacted
by the invasive crayfishes Procambarus clarkii and Pacifastacus leniusculus.
Location: River Sabor, NE Portugal.
Methods: We surveyed amphibians at 168 200-m stream stretches in 2015.
Geostatistical models were used to relate the probabilities of occurrence of each species
to environmental and biotic variables, while controlling for linear (Euclidean) and
hydrologic spatial dependencies. Biotic interactions were specified using crayfish probabilities
of occurrence extracted from previously developed geostatistical models.
Models were used to map the distribution of potential refuges for the most common
amphibian species, under current conditions and future scenarios of crayfish expansion.
Results: Geostatistical models were produced for eight out of 10 species detected,
of which five species were associated with lower stream orders and only one species
with higher stream orders. Six species showed negative responses to one or
both crayfish species, even after accounting for environmental effects and spatial dependencies.
Most amphibian species were found to retain large expanses of potential
habitat in stream headwaters, but current refuges will likely contract under plausible
scenarios of crayfish expansion.
Main conclusions: Incorporating biotic interactions in geostatistical modelling provides a
practical and relatively simple approach to predict present and future distributions of refuges
from biological invasion in stream networks. Using this approach, our study shows
that stream headwaters are key amphibian refuges under invasion by alien crayfish
Description
Biodiversity Research
Keywords
Alien invasive species biological invasions ecological refuges frog geostatistics newt species distribution models stream ecology toad
Pedagogical Context
Citation
Diversity and Distributions. 2020;26:699–714
Publisher
John Wiley and Sons