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The University of Massachusetts Amherst

A climate dependent metapopulation model of marbled salamanders (Ambystoma opacum) in western Massachusetts.


Marbled Salamander reproductive failure is tightly linked to vernal pool hydrology and there are concerns that changes in precipitation patterns predicted due to climate change (drier summers and wetter winters with precipitation being more episodic), along with increased summer temperatures (increased evaporation and evapotranspiration) will significantly change current vernal pool hydrology and possibly lead to more frequent incidents of Marbled Salamander reproductive failure.

Genetic distance data is being used on marbled salamanders collected from 28 vernal pools in western Massachusetts to investigate the landscape resistance of different land cover types and surfaces derived from digital elevation.  This analysis will allow us to infer what surfaces best describe the overall genetic pattern and movement of individuals across the landscape.

Modeling of future vernal pool hydrology based on IPCC models will also provide insight into whether certain vernal pools will become “better” or “worse” for Marbled Salamander reproduction and help decisions makers determine which vernal pools or clusters of vernal pools will be most important to protect based on future forecasted hydrology.  

Dalton Alves, UMass Amherst undergraduate, cropped >13,500 photos of marbled salamanders taken from 1999-2009 at 14 vernal pools in western Massachussets.  We are using Amphident, a photo recognition software program, to match images taken of the same individual. The software has finished matching the >13,500 images (>155 million pairwise comparisons!).  Now we are manually matching and reviewing photos with a high similarity score for each individual image.  Photo matching will allow the development of capture histories of individual salamanders and with this information it is possible to estimate adult survival and breeding frequency using statistical models. Preliminary results indicate that females are more likely to skip breeding in the Fall following a hot dry summer.   Although, individuals that do not breed do not expose themselves to the increased risk of mortality traveling to the pool. Future population modeling will provide insight whether decreased fecundity due to an increased probability of year skipping and changes in vernal pool hydroperiod will have population level impacts in our system.

Kris Winiarski, NE CASC Graduate Fellow, is currently fitting relevant spatial layers to test ecological resistance of different land cover and topographic layers which best describe the movement of marbled salamander genetic data across the landscape here in western Mass.  Preliminary results show high resistance in low lying areas of the pioneer valley which are dominated is dominated by agricultural development.  Future predictions of these surfaces willl exist as part of the DSL project and can be used to assess landscape connectivity for marbled salamanders in the future.