Does a Frog Change its Diet along a Successional Forest Gradient? The Case of the Shovel-Nosed Treefrog ( Diaglena spatulata ) in a Tropical Dry Forest in Western Mexico

Linking agricultural practices to lizard trophic behaviour: An ecological approach

Among intensive agricultural practices, pesticides, mowing, and heavy agricultural machineries have become an important tool to maximize harvesting and secure animal husbandry. However, they are also cause of agricultural ecosystem decline, often leading to degradation of key micro-habitat features for many species, higher predation risk and lower food availability. We investigated the diet and foraging ecology of the Italian wall lizard in agricultural areas to determine whether different management practices (conventional, organic, and control) can affect (i) the structure of the trophic niche of the species; (ii) prey diversity, the degree of individual specialization, and the overall population feeding strategy; (iii) lizards' health status. Faecal pellets were collected for diet composition analyses, while prey diversity in the environment was estimated by placing adhesive traps. Lizards' body condition did not differ among management type although males from control field resulted slightly larger than those from conventional and organic areas. The species showed a generalist (conventional and organic areas) and mixed (control area) feeding strategy with a preference for coleopterans. Although a different prey diversity was found in control areas compared to organic and conventional ones, diet composition and the importance of specific food items was similar among management types. This may suggest that management activities may have affected the overall prey availability and indirectly influenced lizard trophic behaviour. Our study provides a comprehensive knowledge on the feeding ecology of P. siculus in managed habitats, which may have useful implications for the overall conservation of lizards in agricultural environments.

A Salamander tale: Relative abundance, morphometrics and microhabitat of the critically endangered Mexican salamander Pseudoeurycea robertsi (Taylor, 1939)

Roberts’ False Brook Salamander (Pseudoeurycea robertsi) is a critically endangered plethodontid salamander, endemic to the Nevado de Toluca Volcano (NTV), Mexico. Little is known about the biology and ecology of this species, including its microhabitats. Thus, this study aimed to collect basic information about P. robertsi. We sampled fourteen forested sites in the NTV; to corroborate the correct identification of the species we used genetic data, we assessed the variation in head morphometric measurements and dorsal colouration patterns amongst localities and the microhabitat features associated with P. robertsi presence. Of the four potential salamander species, P. robertsi was the most abundant (89.80%) and widely distributed (approximately within 130 km2) salamander in the NTV. We did not find significant variations in morphometry; however, we found significant differences in dorsal patterns between populations (in the number and size of segments of the dorsal stripe). The average total length for 185 adults was 89.15 mm (38.7–117.9 mm); we found seven patterns of dorsal stripe. We found 98% of P. robertsi individuals under the bark of fallen logs in Abies religiosa and A. religiosa-Pinus sp. forests, with a higher number of detected salamanders in naturally-fallen logs than in cut logs (34% vs. 10%). Thus, keeping well-preserved A. religiosa forests and retaining fallen logs is essential to P. robertsi conservation.

Genetic diversity and demography of the critically endangered Roberts' false brook salamander (Pseudoeurycea robertsi) in Central Mexico

Land use changes are threatening the maintenance of biodiversity. Genetic diversity is one of the main indicators of biological diversity and is highly important as it shapes the capability of populations to respond to environmental changes. We studied eleven populations of Pseudoeurycea robertsi, a micro-endemic and critically endangered species from the Nevado de Toluca Volcano, a mountain that is part of the Trans-Mexican Volcanic Belt, Mexico. We sequenced the mitochondrial cytochrome b gene from 71 individuals and genotyped 9 microsatellites from 150 individuals. Our results based on the cytochrome b showed two divergent lineages, with moderate levels of genetic diversity and a recently historical demographic expansion. Microsatellite-based results indicated low levels of heterozygosity for all populations and few alleles per locus, as compared with other mole salamander species. We identified two genetically differentiated subpopulations with a significant level of genetic structure. These results provide fundamental data for the development of management plans and conservation efforts for this critically endangered species.