Using species distribution models with climate change scenarios to aid ecological restoration decisionmaking for southern California shrublands

There are few quantitative predictions for the impacts of climate change on freshwater fish in Australia. We developed species distribution models (SDMs) linking historical fish distributions for 43 species from Victorian streams to a suite of hydro-climatic and catchment predictors, and applied these models to explore predicted range shifts under future climate-change scenarios. Here, we present summary results for the 43 species, together with a more detailed analysis for a subset of species with distinct distributions in relation to temperature and hydrology. Range shifts increased from the lower to upper climate-change scenarios, with most species predicted to undergo some degree of range shift. Changes in total occupancy ranged from –38% to +63% under the lower climate-change scenario to –47% to +182% under the upper climate-change scenario. We do, however, caution that range expansions are more putative than range contractions, because the effects of barriers, limited dispersal and potential life-history factors are likely to exclude some areas from being colonised. As well as potentially informing more mechanistic modelling approaches, quantitative predictions such as these should be seen as representing hypotheses to be tested and discussed, and should be valuable for informing long-term strategies to protect aquatic biota.

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On climate change and subterranean spiders

ARPHA Conference Abstracts ◽

10.3897/aca.1.e29583 ◽

2018 ◽

Vol 1 ◽

Author(s):

Stefano Mammola ◽

Elena Piano ◽

Alexandra Jones ◽

Andrea Dejanaz ◽

Marco Isaia

Keyword(s):

Climate Change ◽

Species Distribution ◽

Thermal Tolerance ◽

Species Distribution Models ◽

Genetic Data ◽

Model Organisms ◽

Climate Change Scenarios ◽

Model Species ◽

Distribution Models ◽

Physiological Tests

Subterranean ecosystems offer intriguing opportunities to study mechanisms underlying responses to changes in climate because species within them are often adapted to largely constant temperatures. However, responses of specialized subterranean species to anthropogenic climate warming are still largely undiscussed. We combined physiological tests, species distribution models and genetic data to investigate the potential effect of raising temperatures on subterranean coenosis. We used spiders of the genus Troglohyphantes Joseph, 1881 (Araneae: Linyphiidae) as model organisms, focusing on a coherent biogeographic area of the Western Alps in which the distribution of these spiders has been well documented. Thermal tolerance experiments in climatic chambers pointed at a reduced physiological tolerance to temperature fluctuations at increasing levels of troglomorphism. This result suggests that, during their subterranean evolution, spiders have progressively fine-tuned thermal tolerance to the constant and narrow temperature ranges of their habitats. Further evidence of the sensitivity of our model species to temperature increase derives from species distribution models projected onto different climate change scenarios. Model projections point toward a future decline in habitat suitability for subterranean spiders. Moreover, genetic data at the population/species interface are suggestive of limited gene flow between subterranean populations, testifying reduced dispersal capacity and habitat connectivity. In light of these results, we predict the potential extinction of the most restricted endemic species. Our findings therefore emphasize the importance of considering subterranean organisms as model species for ecological studies dealing with climatic changes, and to extend such investigations to other subterranean systems worldwide.

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