Variable vulnerability to climate change in New Zealand lizards

Aim: The primary drivers of species and population extirpations have been
habitat loss, overexploitation, and invasive species, but human-mediated
climate change is expected to be a major driver in future. To minimise
biodiversity loss, conservation managers should identify species
vulnerable to climate change and prioritise their protection. Here, we
estimate climatic suitability for two speciose taxonomic groups, then use
phylogenetic analyses to assess vulnerability to climate change. Location:
Aotearoa New Zealand (NZ) Taxa: NZ lizards: diplodactylid geckos and
eugongylinae skinks Methods: We built correlative species distribution
models (SDMs) for NZ geckos and skinks to estimate climatic suitability
under current climate and 2070 future-climate scenarios. We then used
Bayesian phylogenetic mixed models (BPMMs) to assess vulnerability for
both groups with predictor variables for life history traits (body size
and activity phase) and current distribution (elevation and latitude). We
explored two scenarios: an unlimited dispersal scenario, where projections
track climate, and a no-dispersal scenario, where projections are
restricted to areas currently identified as suitable. Results: SDMs
projected vulnerability to climate change for most modelled lizards. For
species’ ranges projected to decline in climatically suitable areas,
average decreases were between 42–45% for geckos and 33–91% for skinks,
although area did increase or remain stable for a minority of species. For
the no-dispersal scenario, the average decrease for geckos was 37–52% and
for skinks was 33–52%. Our BPMMs showed phylogenetic signal in climate
change vulnerability for both groups, with elevation increasing
vulnerability for geckos, and body size reducing vulnerability for skinks.
Main conclusions: NZ lizards showed variable vulnerability to climate
change, with most species’ ranges predicted to decrease. For species whose
suitable climatic space is projected to disappear from within their
current range, managed relocation could be considered to establish
populations in regions that will be suitable under future climates.