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

Abstract

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.Résumé : La compréhension de la dispersion requiert une approche à plusieurs volets, de l'étude des grands motifs de connectivité des populations à la détermination des facteurs qui influencent les déplacements à l'échelle locale. Afin de déterminer les effets potentiels de différents microhabitats sur la dispersion chez la salamandre à longs doigts (Ambystoma macrodactylum Baird, 1850), nous avons évalué expérimentalement la mobilité, la perte d'humidité et le choix de l'habitat en réaction à cinq substrats courants (litières de feuillus et de conifères, herbe, mousse et sable). Plus précisément, nous avons examiné les variations de l'efficacité avec laquelle les salamandres se déplaçaient sur différents substrats quand elles étaient motivées à le faire. Nous avons ensuite quantifié la perte d'humidité dans chaque substrat et évalué les préférences en matière d'habitat. Nos résultats semblent indiquer un compromis entre les substrats qui sont faciles à traverser et ceux qui offrent une bonne protection contre la dessiccation. Le choix de l'habitat semblait reposer sur un équilibre entre ces deux aspects de la performance, les salamandres privilégiant un substrat qui offrait tant une faible résistance au déplacement qu'une bonne protection contre la dessiccation. Ce résultat dépend du contexte, la préférence allant à des substrats plus humides, mais moins faciles à traverser quand des objets offrant un couvert additionnel étaient fournis. Globalement, l'étude fait ressortir le potentiel des individus de réagir à un substrat donné de manière aus...

Locomotor endurance predicts differences in realized dispersal between sympatric sexual and unisexual salamanders

“…The direction of this bias is not understood because there are currently no comparative studies between species (Stevens et al . ; Lee‐Yaw, Sechley & Irwin ). Because the landscape of Crawford Country is largely homogeneous (field, road, small forest patches), we expect that there is little opportunity for differential dispersal among substrate types that could account for differences in movement between sexuals and unisexuals.…”

Thermally buffered microhabitats recovery in tropical secondary forests following land abandonment

“…Moss -Moss is an important microhabitat for insects and amphibians (TarkowskaKukuryk and Mieczan 2014;Lee-Yaw, Sechley et al 2015). In each plot, we delimited fifteen 1 m 2 quadrats (following (Urbina and Galeano 2009)).…”

“…In each plot, we delimited fifteen 1 m 2 quadrats (following (Urbina and Galeano 2009)). Moss height and density defines how easy species move through it (Lee-Yaw, Sechley et al 2015)). Therefore, moss was assessed in such a way as to retain moss original structure during measurement.…”