Frog survival and population viability in an agricultural landscape with a drying climate

Abstract

Amphibians are the most threatened class of vertebrate in the world. Although a number of causes of the amphibian decline phenomenon are emerging, there is a need for robust demographic data to be able to monitor current and future threats such as climate change. Despite this, few studies on amphibians have the lifehistory data available to undertake these analyses and fewer still have looked at the challenges to population viability posed by fragmentation-a feature inherent in agricultural landscapes where the matrix is highly modified. Our aim was to investigate the population viability of a large burrowing frog in an agricultural landscape. Specifically, we aimed to investigate the future persistence of populations under a range of scenarios including populations connected by various levels of dispersal and reduced rainfall. We used the life-history parameters of Heleioporus albopunctatus, a frog species widely distributed in the extensively cleared agricultural regions of south-western Australia. We investigated the viability of 24 partially connected populations under a range of scenarios using the program Vortex Version 10.1.6.0. Metapopulations were consistently more robust to extinction than isolated local populations. Both meta-and local populations were more susceptible to increases in age-specific mortality rates than to variation in the estimated ability of H. albopunctatus to disperse between breeding ponds, the survival rate of dispersers, or the frequency of drought. Our results reinforce the importance of metapopulations for survival in fragmented landscapes and point to the need to manage amphibian breeding ponds across landscapes to ensure high survival rates, particularly for juveniles.

Life history traits and reproductive ecology of North American chorus frogs of the genus Pseudacris (Hylidae)

“…There is considerable uncertainty in survival probabilities of juvenile chorus frogs, a pattern that is observed for many amphibians [ 229 , 230 ]. The complexity of marking and recapturing metamorphic and juvenile anurans make estimating survival very difficult [ 225 ].…”

Temporary pond loss as a result of pasture abandonment: exploring the social-ecological drivers and consequences on amphibians

“…It is expected that the disappearance of the ponds and / or the decrease of their quality narrows the habitat diversity for several species, forcing amphibians to breed in suboptimal – i.e. sink- habitats (Pulliam, 2014) and decreasing the population and metapopulation viability in changing climate (Davis, Lohr & Roberts, 2018). The nearest pond distance in our study as a proxy of pond connectivity showed a slight increase with the pond loss, but the overall distances even with the loss of temporary ponds (Table 1) remained within the movement range of most species (i.e.…”

The social context for conservation: amphibians in human-shaped landscapes

“…In some contexts, population viability modeling and decision analysis provide valuable tools for projecting future populations states (Converse and Grant, 2019;Davis et al 2019). However, in many human-shaped landscapes these approaches may have limited practical applicability, particularly where natural and cultural values are threatened by various economic interests and conflicts between stakeholders regarding nature conservation goals are common (Hartel et al 2019).…”