Population demography of the Tasmanian short-beaked echidna (

Abstract

Deriving estimates of demographic parameters and the processes driving them is crucial for identifying wildlife management options. The short-beaked echidna (Tachyglossus aculeatus) is the most widely distributed native Australian mammal, yet little is known of its population dynamics due to its cryptic nature. Consequently, assessment of the impacts of climate and threats on echidna populations has been difficult. We analyse 19 years (1996–2014) of mark–recapture data to estimate survival and reproductive rates of a Tasmanian population of short-beaked echidna, and to evaluate the influence of regional weather patterns on its demographics. Population size showed high year-to-year variation, ranging from 1 to 40 echidnas km2 across the study area. Known-fate modelling of radio-tracked individuals suggested that climatic conditions impacted survival; average longevity was estimated at 16.7 years but only 4.8 years when the total spring/summer rainfall was below 125 mm, and 6.25 in years when temperatures more frequently exceeded 32°C. Recruitment, estimated from Pradel analyses, was low in the population (β = 0.08) and not significantly affected by climate. These results are the first quantitative estimates of climate effects, survival, and recruitment for this species, and suggest that climate-enhanced drying and temperature increase would pose a threat to echidna populations in Tasmania.