Niche shift and resource supplementation facilitate an amphibian range expansion
Date
2019
Journal Title
Journal ISSN
Volume Title
Publisher
Wiley
Abstract
Aim: To determine whether recent range expansion of small- bodied arboreal frogs,
Hyperolius marmoratus Rapp, is accompanied by changes in species–environment re-
lationships and whether its historical range was constrained by climate, availability of
water bodies or topographic variables. We test if artificial water bodies in the novel
range have facilitated niche shift by increasing available habitats for frog
establishment.
Location: Western Cape Province, South Africa, with reference to the broader spe-
cies range in southeastern Africa.
Methods: We build species distribution models using occurrence data from the his-
torical and novel ranges and reciprocally project them to highlight areas of putative
niche change. We test for niche shift through ordination- based approaches to disen-
tangle how species–environment relationships may have altered and whether climate
or landscape features (artificial water bodies and topography) are more strongly as-
sociated with the identified change. We further decompose niche change into areas
of expansion and unfilling to quantify niche shift and describe potential future spread.
Results: We observed niche expansion into novel environmental space, with 21% of
niche space in the invaded range composed of environments that were not occupied
in the native range. We also observed 16% niche unfilling, signifying range disequilib-
rium and potential for further spread. Mean annual precipitation and proximity to
water bodies were more influential in models constructed in the novel range than in
historical or combined range models, suggesting that presence of artificial water
bodies in the landscape ameliorates novel range conditions. Together, these metrics
suggest that range expansion may be ongoing based on climate and water body
availability.
Main conclusions: Our analyses identify a realised niche shift that has allowed
painted reed frogs to occupy drier and more thermally variable habitats in their novel
(invaded) range. This shift may be mediated by artificial water bodies that provide
additional buffered habitats, a key resource supplement for these small- bodied tropi-
cal frogs.
Description
CITATION: Davies, S. J., et al. 2019. Niche shift and resource supplementation facilitate an amphibian range expansion. Diversity and Distributions, 25(1):154-165, doi:10.1111/ddi.12841.
The original publication is available at https://onlinelibrary.wiley.com
The original publication is available at https://onlinelibrary.wiley.com
Keywords
Invasive species, Niche (Ecology) -- South Africa -- Western Cape Province, Invasive species -- Management, Niche model -- Environmental aspects, Amphibians -- Effect of environment on
Citation
Davies, S. J., et al. 2019. Niche shift and resource supplementation facilitate an amphibian range expansion.
Diversity and Distributions, 25(1):154-165, doi:10.1111/ddi.12841