Behavioural patterns of two native Leiopelma frogs and implications for their conservation

<p>Amphibian populations are in general decline internationally. The current situation of amphibian populations highlights the urgent need for comprehensive information on species’ ecology to better assess conservation and management strategies. Movement behaviour and microhabitat selection give insights into how amphibians use the environment and interact with their surroundings, and are essential to establishing their sensitivity to the global decline phenomenon and identifying the critical habitat features essential for their success. New Zealand native frogs (Anura: Leiopelmatidae, Leiopelma, nine species) were formerly distributed throughout New Zealand, but habitat modification and predation by introduced mammalian predators have influenced recent (Holocene) extinctions and declines, reducing the fauna to four species with major range reductions. All extant Leiopelma are classified as threatened both nationally and internationally, creating an urgent need for species-specific behavioural research to support conservation management. I investigated activity, movement behaviour and microhabitat use of L. archeyi and L. pakeka for better evaluation of long term population viability and improved husbandry in captivity. L. archeyi is the smallest of the Leiopelma species and has been able to co-occur with introduced predators (e.g. rats), whereas L. pakeka is the largest, and the only natural population is confined to a predator-free island. I used a fine-scale tracking technique (i.e. non-toxic fluorescent powders) to track L. archeyi and L. pakeka movements throughout their activity periods when on the surface in their natural habitats, Whareorino Forest and Maud Island, respectively, to obtain detailed information on their activity patterns, movement behaviour, and microhabitat and retreat site use. I investigated in more detail L. pakeka retreat sites by measuring the dimensions of the retreat site entrances (width, height and diameter) as well as the activity inside those retreat sites. Lastly, I used long-term frog survey data to examine the indirect impacts (i.e. behavioural changes) ship rats (Rattus rattus) may have on L. archeyi by studying the microhabitat use and home range of this species in an area with and without rat control within Whareorino Forest. L. archeyi had a longer activity period than L. pakeka with the former being active up to two hours after sunrise, but L. pakeka moved more and further than L. archeyi during their activity periods. Additionally, L. archeyi had a smaller home range compared to L. pakeka which suggests more prominent site fidelity and more sedentary behaviour in this species. Both species actively sought out specific microhabitats among the ones that were available, either to use during movement or to use as retreat sites, but those microhabitat types also differed between species. L. archeyi were more often found above ground level than L. pakeka and tended to use microhabitats that provided cover. L. archeyi preferred to use trees as retreat sites (roots, branches or trunk) whereas L. pakeka used trees (roots) and rocks. L. pakeka retreat sites had lower and more stable temperatures than outside retreats. Frogs were active inside retreats with no evidence of sleep behaviour for at least the first few hours of retreat use. In the rat control area, L. archeyi used more soil, leaf litter and ferns, and were also more likely to be found at ground level than frogs in the presence of higher numbers of rats. Abiotic factors also influenced movement patterns and microhabitat selection of both species, affirming water balance and thermoregulation are important drivers in frog behaviour. Behavioural attributes and small body size could be aiding in the persistence of L. archeyi in the presence of rats, and large body size and differences in behavioural attributes are likely to put L. pakeka at risk if rats were to reach their habitat. My findings inform on the ecology and behaviour of two Leiopelma species providing valuable information on their habitat requirements, which will enable more effective captive husbandry and better assessment of the appropriateness of translocation sites, aiding in their conservation management.</p>

Behavioural patterns of two native Leiopelma frogs and implications for their conservation

<p>Amphibian populations are in general decline internationally. The current situation of amphibian populations highlights the urgent need for comprehensive information on species’ ecology to better assess conservation and management strategies. Movement behaviour and microhabitat selection give insights into how amphibians use the environment and interact with their surroundings, and are essential to establishing their sensitivity to the global decline phenomenon and identifying the critical habitat features essential for their success. New Zealand native frogs (Anura: Leiopelmatidae, Leiopelma, nine species) were formerly distributed throughout New Zealand, but habitat modification and predation by introduced mammalian predators have influenced recent (Holocene) extinctions and declines, reducing the fauna to four species with major range reductions. All extant Leiopelma are classified as threatened both nationally and internationally, creating an urgent need for species-specific behavioural research to support conservation management. I investigated activity, movement behaviour and microhabitat use of L. archeyi and L. pakeka for better evaluation of long term population viability and improved husbandry in captivity. L. archeyi is the smallest of the Leiopelma species and has been able to co-occur with introduced predators (e.g. rats), whereas L. pakeka is the largest, and the only natural population is confined to a predator-free island. I used a fine-scale tracking technique (i.e. non-toxic fluorescent powders) to track L. archeyi and L. pakeka movements throughout their activity periods when on the surface in their natural habitats, Whareorino Forest and Maud Island, respectively, to obtain detailed information on their activity patterns, movement behaviour, and microhabitat and retreat site use. I investigated in more detail L. pakeka retreat sites by measuring the dimensions of the retreat site entrances (width, height and diameter) as well as the activity inside those retreat sites. Lastly, I used long-term frog survey data to examine the indirect impacts (i.e. behavioural changes) ship rats (Rattus rattus) may have on L. archeyi by studying the microhabitat use and home range of this species in an area with and without rat control within Whareorino Forest. L. archeyi had a longer activity period than L. pakeka with the former being active up to two hours after sunrise, but L. pakeka moved more and further than L. archeyi during their activity periods. Additionally, L. archeyi had a smaller home range compared to L. pakeka which suggests more prominent site fidelity and more sedentary behaviour in this species. Both species actively sought out specific microhabitats among the ones that were available, either to use during movement or to use as retreat sites, but those microhabitat types also differed between species. L. archeyi were more often found above ground level than L. pakeka and tended to use microhabitats that provided cover. L. archeyi preferred to use trees as retreat sites (roots, branches or trunk) whereas L. pakeka used trees (roots) and rocks. L. pakeka retreat sites had lower and more stable temperatures than outside retreats. Frogs were active inside retreats with no evidence of sleep behaviour for at least the first few hours of retreat use. In the rat control area, L. archeyi used more soil, leaf litter and ferns, and were also more likely to be found at ground level than frogs in the presence of higher numbers of rats. Abiotic factors also influenced movement patterns and microhabitat selection of both species, affirming water balance and thermoregulation are important drivers in frog behaviour. Behavioural attributes and small body size could be aiding in the persistence of L. archeyi in the presence of rats, and large body size and differences in behavioural attributes are likely to put L. pakeka at risk if rats were to reach their habitat. My findings inform on the ecology and behaviour of two Leiopelma species providing valuable information on their habitat requirements, which will enable more effective captive husbandry and better assessment of the appropriateness of translocation sites, aiding in their conservation management.</p>

Characterization of the microbiome of the invasive Asian toad in Madagascar across the expansion range and comparison with a native co-occurring species

Biological invasions are on the rise, with each invader carrying a plethora of associated microbes. These microbes play important, yet poorly understood, ecological roles that can include assisting the hosts in colonization and adaptation processes or as possible pathogens. Understanding how these communities differ in an invasion scenario may help to understand the host’s resilience and adaptability. The Asian common toad, Duttaphrynus melanostictus is an invasive amphibian, which has recently established in Madagascar and is expected to pose numerous threats to the native ecosystems. We characterized the skin and gut bacterial communities of D. melanostictus in Toamasina (Eastern Madagascar), and compared them to those of a co-occurring native frog species, Ptychadena mascareniensis, at three sites where the toad arrived in different years. Microbial composition did not vary among sites, showing that D. melanostictus keeps a stable community across its expansion but significant differences were observed between these two amphibians. Moreover, D. melanostictus had richer and more diverse communities and also harboured a high percentage of total unique taxa (skin: 80%; gut: 52%). These differences may reflect the combination of multiple host-associated factors including microhabitat selection, skin features and dietary preferences.

Calling site selection by male Boana punctata (Anura: Hylidae)

Amphibian species require specific conditions for reproduction, such as cover structures and shelters, in both aquatic and terrestrial habitats, which directly influence reproductive success. A careful selection of calling sites is an important process, driving life-history strategies and tactics in amphibians. Despite this, a significant knowledge gap on how different variables modulate amphibian microhabitat selection processes is noted. Thus, we aimed to: (1) describing the microhabitat use of adult neotropical Boana punctata males during the breeding season; and (2) quantitatively analyzing the selection process of five resource variables (i.e., vegetation cover, vegetation density, vegetation height, water depth, and distance to the water shore). We then compared the microhabitat selection of males that achieved spawning and that of males that did not achieve spawning. To quantify selection, we used a resource selection function approach, applying a case/control design where the calling site used by each male was paired to eight surrounding, unused locations. We found that males selected microhabitats with higher vegetation than surrounding areas for reproduction, which suggests territorialism, and selected microhabitats slightly (∼ 30 cm) inside the assessed ponds. Males also acted randomly with regard to the other variables, not influencing the males’ microhabitat selection. Microhabitat use of males successful in obtaining females to spawn was similar to that of males exhibiting mating failure. In addition to being of ecological interest, our study highlights that preserving tall vegetation and the ponds’ shores is important for the conservation of existing B. punctata urban populations.

Microhabitat selection of the poorly known lizard Tropidurus lagunablanca (Squamata: Tropiduridae) in the Pantanal, Brazil

Understanding how different environmental factors influence species occurrence is a key issue to address the study of natural populations. However, there is a lack of knowledge on how local traits influence the microhabitat use of tropical arboreal lizards. Here, we investigated the microhabitat selection of the poorly known lizard Tropidurus lagunablanca (Squamata: Tropiduridae) and evaluated how environmental microhabitat features influence animal’s presence. We used a Resource Selection Function approach, in a case/control design where we analyzed the effect of substrate temperature and tree’s diameter at breast height (DBH) in the probability of presence of lizards using mixed Conditional Logistic Regression. We found that T. lagunablanca uses trees with DBH from 0.40 m to 4 m and substrate temperatures ranging from 25.9℃ to 42℃. Moreover, we showed that thickness of the trees and substrate temperatures significantly increased the probability of presence of T. lagunablanca individuals, being the probability of presence higher than 50% for trees up to 1.5 m DBH and temperature of substrate up to 37.5℃. Our study probed that T. lagunablanca individuals choose trees non-randomly, selecting thicker and warmer tree trunks. This information advances the knowledge of the spatial ecology of Neotropical arboreal lizards and is relevant for conservation, putting an emphasis on preserving native vegetation in the Pantanal.

Spatial Utilization and Microhabitat Selection of the Snow Leopard (Panthera uncia) under Different Livestock Grazing Intensities

There is increasing conflict between snow leopards and humans in many protected areas, the main driver of which is the overlap in spatial utilization between snow leopards and livestock. Understanding the spatial utilization and microhabitat selection of snow leopards in areas featuring different levels of livestock grazing is important to better understand and resolve this conflict, but such studies are rare. Here, we conducted line transect and plot surveys in low- and high-grazing-disturbance areas (LGDAs and HGDAs) in Wolong National Reserve, southwestern China. We compared snow leopard spatial utilization and microhabitat characteristics between LGDAs and HGDAs. Results showed that snow leopards had aggregated distribution in both LGDAs and HGDAs, but the distribution of snow leopards in HGDAs was more centralized than in LGDAs. Herb cover and height in LGDAs were greater than in HGDAs. We fit a resource selection function (RSF) that showed that snow leopards preferentially selected higher elevation, smaller basal diameter of shrubs, and lower height of herbs in LGDAs. In contrast, there were no significant microhabitat factors in our snow leopard RSF in HGDAs. Our results indicate that high-intensity grazing tends to reduce the habitat types available to and preferential selectivity of habitat by snow leopards. We recommend that livestock grazing should be controlled to restore the diversity of the alpine ecosystems in Wolong Nature Reserve. Our findings also highlight the need for evaluating the impact of livestock grazing on rare animals in alpine environments (e.g., snow leopard) in other areas facing similar issues.