Long-toed Salamander (Ambystoma macrodactylum) hibernacula in Waterton Lakes National Park revealed using Passive Integrated Transponder telemetry

Long-toed Salamanders (Ambystoma macrodactylum) spend most of their lives on land; however, their fossorial nature makes studying their use of habitat difficult. Using Passive Integrated Transponder (PIT) telemetry over two years, we found and characterized nine overwintering sites of Long-toed Salamanders in the vicinity of Linnet Lake and Stable Pond in Waterton Lakes National Park, excavating five of them. These sites were typically associated with stumps and decaying root systems that gave the salamanders access to deep subterranean hibernacula. Overwintering sites were located up to 168 m from the shores of breeding ponds. Given the importance of such terrestrial sites to these populations of Long-toed Salamanders, it is vital that conservation efforts include the preservation of these features and ensure that a sufficient area surrounding breeding ponds remains undisturbed.

Role of habitat complexity in predator–prey dynamics between an introduced fish and larval Long-toed Salamanders (Ambystoma macrodactylum)

Predation by nonnative fishes has reduced abundance and increased extinction risk for amphibian populations worldwide. Although rare, fish and palatable amphibians have been observed to coexist where aquatic vegetation and structural complexity provide suitable refugia. We examined whether larval Long-toed Salamanders (Ambystoma macrodactylum Baird, 1850) increased use of vegetation cover in lakes with trout and whether adding vegetation structure could reduce predation risk and nonconsumptive effects (NCEs), such as reductions in body size and delayed metamorphosis. We compared use of vegetation cover by larval salamanders in lakes with and without trout and conducted a field experiment to investigate the influence of added vegetation structure on salamander body morphology and life history. The probability of catching salamanders in traps in lakes with trout was positively correlated with the proportion of submerged vegetation and surface cover. Growth rates of salamanders in enclosures with trout cues decreased as much as 85% and the probability of metamorphosis decreased by 56%. We did not find evidence that adding vegetation reduced NCEs in experimental enclosures, but salamanders in lakes with trout used more highly vegetated areas, which suggests that adding vegetation structure at the scale of the whole lake may facilitate coexistence between salamanders and introduced trout.

Conflicting effects of microhabitats on Long-toed Salamander (Ambystoma macrodactylum) movement: implications for landscape connectivity

Understanding dispersal requires multiple lines of investigation, from the study of broad patterns of population connectivity to the identification of factors impacting movement at local scales. To determine the potential effects of different microhabitats on dispersal in the Long-toed Salamander (Ambystoma macrodactylum Baird, 1850), we experimentally evaluated mobility, moisture loss, and habitat choice in response to five common substrates (deciduous and coniferous leaf litter, grass, moss, and sand). Specifically, we examined differences in the efficiency with which salamanders moved across substrates when motivated to move. We then quantified moisture loss in each substrate and evaluated habitat preference. Our results point to a trade-off between substrates that are easily traversed and those that offer high protection against desiccation. Habitat choice appeared to balance these two aspects of performance, with salamanders favouring a substrate that offered both low resistance to movement and high protection against desiccation. This result was context-dependent, as preferences shifted towards wetter but less easily traversed substrates when supplemental cover objects were made available. Overall, our study highlights the potential for individuals to respond to a given substrate in ways that can both facilitate and limit dispersal and thus underscores the need to consider different aspects of individual performance and behaviour when studying population connectivity.