logo

Caballero-Díaz, C., Sánchez-Montes, G., Gómez, I., Díaz-Zúñiga, A., & Martínez-Solano, Í. (2022). Artificialwater bodies as amphibian breeding sites: the case of the common midwife toad (Alytes obstetricans) in central Spain, Amphibia-Reptilia (published online ahead of print 2022). doi: https://doi.org/10.1163/15685381-bja10115

Natural breeding sites for amphibians are decreasing in quantity and quality in temperate regions, resulting in local extinctions and increasing population fragmentation. Artificial water bodies (e.g., water tanks or cattle troughs) can represent suitable reproductive habitats for some amphibians, but demographic data are required to assess this assumption. We evaluated the role of artificial water bodies in the persistence of a species of population concern, the common midwife toad, Alytes obstetricans (Laurenti, 1768), at local and regional scales. We surveyed 275 water bodies to characterize the distribution of the species and detected 63 breeding populations of A. obstetricans where we estimated larval abundance. In addition, we monitored two populations for three consecutive breeding seasons using capture-mark-recapture methods based on photo-identification, assessing abundance, breeding success and the use of space of adult individuals captured on multiple occasions. Our results show that artificial sites are preferentially used as breeding sites in the region compared to natural aquatic habitats, providing key habitat for the species and hosting much larger numbers and densities of larvae than natural sites. At local scale, populations of A. obstetricans in artificial sites were abundant and characterized by high male breeding success. However, adults are spatially aggregated around breeding sites, with small home ranges, implying high vulnerability to population fragmentation. Our results suggest artificial breeding sites can sustain viable populations of A. obstetricans, provided measures promoting connectivity among breeding nuclei are considered.

We obtained kernels of variable robustness for six species. Node importance for connectivity varied between species, but with common patterns such as shared road crossing areas and the presence of coincident interconnected pond clusters. The combination of photoidentification, capture-recapture data and graph theory allowed us to characterize functional connectivity across the pondscape of study accounting for dispersal variability and identify areas where conservation actions could be most efficient. Our results highlight the need to account for interspecific differences in the study and management of amphibian pondscapes. Leer más.

https://media.springernature.com/lw685/springer-static/image/art%3A10.1007%2Fs10980-022-01520-x/MediaObjects/10980_2022_1520_Fig4_HTML.png?as=webp

We address two classification experiments: (1) assignment of images of the morphologically relatively distinct P. bocagei and P. lusitanicus; and (2) distinction between the overall more cryptic nine taxa that compose this complex. We used four datasets (two image perspectives and individuals of the two sexes) and three deep-learning models to address each problem. Our results suggest a high ability of the models to identify the correct species, especially when combining predictions from different perspectives and models (accuracy of 95.9% and 97.1% for females and males, respectively, in the two-class case; and of 91.2% to 93.5% for females and males, respectively, in the nine-class case). Leer más.

https://oup.silverchair-cdn.com/data/SiteBuilderAssets/Live/Images/zoolinnean/zoolinnean_h1404917972.png