Species interactions and the effects of climate variability on a wetland amphibian metacommunity

Abstract

Disentangling the role that multiple interacting factors have on species responses to shifting climate poses a significant challenge. However, our ability to do so is of utmost importance to predict the effects of climate change on species distributions. We examined how populations of three species of wetland-breeding amphibians, which varied in life history requirements, responded to a six-year period of extremely variable precipitation. This interval was punctuated by both extensive drought and heavy precipitation and flooding, providing a natural experiment to measure community responses to environmental perturbations. We estimated occurrence dynamics using a discrete hidden Markov modeling approach that incorporated information regarding habitat state and predator-prey interactions. This approach allowed us to measure how metapopulation dynamics of each amphibian species was affected by interactions among weather, wetland hydroperiod, and co-occurrence with fish predators. The pig frog, a generalist, proved most resistant to perturbations, with both colonization and persistence being unaffected by seasonal variation in precipitation or co-occurrence with fishes. The ornate chorus frog, an ephemeral wetland specialist, responded positively to periods of drought owing to increased persistence and colonization rates during periods of low-rainfall. Low probabilities of occurrence of the ornate chorus frog in long-duration wetlands were driven by interactions with predators due to low colonization rates when fishes were present. The mole salamander was most sensitive to shifts in water availability. In our study area, this species never occurred in short-duration wetlands and persistence probabilities decreased during periods of drought. At the same time, negative effects occurred with extreme precipitation because flooding facilitated colonization of fishes to isolated wetlands and mole salamanders did not colonize wetlands once fishes were present. We demonstrate that the effects of changes in water availability depend on interactions with predators and wetland type and are influenced by the life history of each of our species. The dynamic species occurrence modeling approach we used offers promise for other systems when the goal is to disentangle the complex interactions that determine species responses to environmental variability.

The recent past and promising future for data integration methods to estimate species’ distributions

“…Information about the occurrence or abundance of one species informs the presence of another. Similarly, these models have been extended to incorporate community dynamics (Davis et al., ; Miller, Brehme, Hines, Nichols, & Fisher, ; Yackulic et al., ). These methods could naturally be extended to incorporate data integration methods.…”

Modeling competition, niche, and coexistence between an invasive and a native species in a two‐species metapopulation

“…, Davis et al. ). These studies take into account imperfect species detection, a critical issue for any observational study, that, if neglected, can lead to biased inferences (review in Guillera‐Arroita ).…”

Multistate occupancy modeling improves understanding of amphibian breeding dynamics in the Greater Yellowstone Area

“…However, climate, local factors, and life history characteristics are likely to influence amphibian occupancy and breeding dynamics in ways that are consistent with demographic‐based life history theory (Davis et al. ). For example, if wetland habitat remains suitable among years, we would expect the breeding probability for all species to be high, unless predators such as fish inhabit these permanent wetlands.…”

“…, Davis et al. ). Specifically, we used current and lagged estimates of precipitation, evapotranspiration, and runoff to examine how these climate drivers influence a decade of annual wetland patterns across our study area.…”