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The relationship between an island’s size and the number of species on that island—the island species–area relationship (ISAR)—is one of the most well-known patterns in biogeography and forms the basis for understanding biodiversity loss in response to habitat loss and fragmentation. Nevertheless, there is contention about exactly how to estimate the ISAR and the influence of the three primary ecological mechanisms that drive it — random sampling, disproportionate effects, and heterogeneity. Key to this contention is that estimates of the ISAR are often confounded by sampling and estimates of measures (i.e., island-level species richness) that are not diagnostic of potential mechanisms. Here, we advocate a sampling-explicit approach for disentangling the possible ecological mechanisms underlying the ISAR using parameters derived from individual-based rarefaction curves estimated across spatial scales. If the parameters derived from rarefaction curves at each spatial scale show no relationship with island area, we cannot reject the hypothesis that ISARs result only from random sampling. However, if the derived metrics change with island area, we can reject random sampling as the only operating mechanism and infer that effects beyond sampling (i.e., disproportionate effects and/or heterogeneity) are also operating. Finally, if parameters indicative of within-island spatial variation in species composition (i.e., β-diversity) increase with island area, we can conclude that intra-island compositional heterogeneity plays a role in driving the ISAR. We illustrate this approach using representative case studies, including oceanic islands, natural island-like patches, and habitat fragments from formerly continuous habitat, illustrating several combinations of underlying mechanisms. This approach will offer insight into the role of sampling and other processes that underpin the ISAR, providing a more complete understanding of how, and some indication of why, patterns of biodiversity respond to gradients in island area.

Habitat fragmentation is a major driver of biodiversity loss and among reptiles has been attributed as a cause of species decline. The negative effect of habitat fragmentation has also been shown to be worse for species that are habitat specialists. The Dunes Sagebrush Lizard (Sceloporus arenicolus Degenhardt and Jones, 1972) is a species that specializes on the shinnery oak (Quercus havardii Rydb.) sand-dune landform of the Mescalero-Monahans Sandhills ecosystem in western Texas and eastern New Mexico, USA. This landform has been fragmented by roads and well pads used for the extraction of oil and gas resources. The effects of fragmentation on the home range and movements of this species can lead to the effective isolation of populations and increased risk of localized extirpations. We showed that home-range size was larger in an unfragmented area and that the mean distance of movements was greater. We also observed that roads in the fragmented areas restricted movements of S. arenicolus. We concluded that roads can be barriers to movements even though only narrow strips of habitat are altered. Key words: habitat loss, species decline, Mescalero-Monahans Sandhills, Phrynosomatidae, oil and gas development, road ecology, Sceloporus arenicolus, Dunes Sagebrush Lizard. La fragmentation d'habitats est un important facteur de perte de biodiversité et, chez les reptiles, a été interprétée comme étant une cause du déclin d'espèces. Il a également été démontré que l'effet négatif de la fragmentation d'habitats est plus important pour les espèces spécialistes en ce qui concerne l'habitat. Le lézard des armoises du désert (Sceloporus arenicolus Degenhardt et Jones, 1972) est un spécialiste du relief de dunes de sable à chênes de Harvard (Quercus havardii Rydb.) de l'écosystème des collines de sable de Mescalero-Monahans de l'ouest du Texas et de l'est du Nouveau-Mexique (États-Unis). Ce relief a été fragmenté par des routes et plateformes d'exploitation utilisées pour l'extraction de ressources pétrolières et gazières. Les effets de la fragmentation sur le domaine vital et les déplacements de cette espèce peuvent mener à l'isolement effectif de populations et un risque accru de disparition locale. Nous montrons que la taille des domaines vitaux est plus grande dans une zone non fragmentée et que la distance moyenne des déplacements y est plus grande. Nous observons également que les routes dans les zones fragmentées restreignent les déplacements de S. arenicolus. Nous en concluons que les routes peuvent constituer des barrières aux déplacements même si seules d'étroites bandes d'habitat sont modifiées. [Traduit par la Rédaction] Mots-clés : perte d'habitat, déclin des espèces, collines de sable de Mescalero-Monahans, phrynosomatidés, mise en valeur des ressources pétrolières et gazières, écologie des routes, Sceloporus arenicolus, lézard des armoises du désert., Introduction Habitat fragmentation is a process through which a landscape is broken into a number of smaller, more isolated patches, separated by unsuitable habitat and is always associated with habitat [...]

Translocations are often characterized as "successes" or "failures". However, this dichotomy masks the challenges of successful translocations and ignores important lessons learned in cases where a population was not established in perpetuity. We translocated 76 individuals of an imperiled endemic lizard, the Dunes Sagebrush Lizard (Sceloporus arenicolus), to a locality where it had gone extinct. Translocated lizards survived and reproduced in small numbers. Based on intensive monitoring, we were able to conclude the incipient population declined to zero individuals after 4 years. It is possible that predation, Allee effects, or stochastic factors prevented the population from sustaining itself at this historically occupied site. Valuable lessons for conservation translocations can be taken from this case. We offer novel perspectives on the IUCN Guidelines for Reintroductions and Other Conservation Translocations regarding release site selection, propagule bias, behavioral monitoring, population monitoring, and issues of land tenure. We recommend pairing knowledge of habitat requirements with quantitative analyses to select suitable release sites, translocating gravid females to jump‐start population growth, coupling delayed releases with intensive behavioral monitoring, using Poisson‐based models to determine necessary intensity of monitoring, and recognizing how issues of land tenure may present pitfalls for conservation translocations in the long term. [ABSTRACT FROM AUTHOR]

Simple Summary: The disappearance of many reptiles and amphibian species is directly and indirectly connected with habitat modification, introducing invasive species, disease, pollution, and climate change. Monitoring endangered species is essential for conservation action to mitigate the predominant threats to endangered species. According to wildlife researchers, visual information provides definitive evidence of an animal's distribution patterns and activity within an environmental context. At the Department of Biology and The Ingram School of Engineering at Texas State University and Texas A&M University, we collaborated on a camera trap project to monitor species from images in Texas, USA. We developed a framework to analyze the acquired images using artificial intelligence-driven technology and computer vision methods. The project aims to classify three broad groups of herpetofaunal species (i.e., toads/frogs, lizards, and snakes) from camera trap images with deep learning architectures. The experiment includes balancing the imbalanced dataset, investigating several image preprocessing techniques, and augmentation procedures. The classification results present tremendous prospects for automated species identification from challenging biological image data. The research outcome is essential to the academic community and wildlife researchers for conservation and monitoring purpose. Accurate identification of animal species is necessary to understand biodiversity richness, monitor endangered species, and study the impact of climate change on species distribution within a specific region. Camera traps represent a passive monitoring technique that generates millions of ecological images. The vast numbers of images drive automated ecological analysis as essential, given that manual assessment of large datasets is laborious, time-consuming, and expensive. Deep learning networks have been advanced in the last few years to solve object and species identification tasks in the computer vision domain, providing state-of-the-art results. In our work, we trained and tested machine learning models to classify three animal groups (snakes, lizards, and toads) from camera trap images. We experimented with two pretrained models, VGG16 and ResNet50, and a self-trained convolutional neural network (CNN-1) with varying CNN layers and augmentation parameters. For multiclassification, CNN-1 achieved 72% accuracy, whereas VGG16 reached 87%, and ResNet50 attained 86% accuracy. These results demonstrate that the transfer learning approach outperforms the self-trained model performance. The models showed promising results in identifying species, especially those with challenging body sizes and vegetation. [ABSTRACT FROM AUTHOR]

The conservation of rarely encountered species is notoriously difficult mainly because of the lack of information about their natural history. This is definitely the case for the spot-tailed earless lizards (Holbrookia lacerata and H. subcaudalis). Sparse distributional records and infrequent observations at known sites were used as evidence to petition these species for protection under the Endangered Species Act. For this study, we did surveys in historic and new areas to determine the current distribution of both species. We also radio-tracked individuals from two populations to estimate movement potential and home range sizes, as well as understand habitat use. Distribution surveys indicate that H. lacerata has undergone range contraction (39%); however, H. subcaudalis was historically found in 21 counties but we only observed them in five. We found home ranges to be relatively large compared to similarly sized insectivores and at least four times larger than the similar H. maculata. Both species are inhabitants of historic grasslands, but within this habitat type they used sites that were more open compared to what was available, including areas such as row-crop agriculture and frequently mowed fields. Frequent habitat disturbance seems to be important for both species. Urbanisation, invasive woody vegetation and invasive grasses are all considered threats that may have already caused declines to both species. [ABSTRACT FROM AUTHOR]

We examined genetic relationships among individuals and populations of the species Holbrookia lacerata, the spot-tailed earless lizard, using whole mitochondrial genomes. Lizards were collected from south, central and west Texas. We found significant amounts of genetic structure among populations and evidence of two major reciprocally monophyletic groups of spot-tailed earless lizards in Texas. Holbrookia lacerata lacerata occurs on the Edwards Plateau and adjacent regions of West Texas north of the Balcones Escarpment, while Holbrookia lacerata subcaudalis occurs in South Texas and adjacent Mexico south of the Balcones Escarpment. These two recognised subspecies correspond to the two clades we discovered. Holbrookia l. lacerata occupies much of its historical range at sometimes high population densities, while populations of H. l. subcaudalis appear to be highly fragmented based on recent observations compared to their historical range. [ABSTRACT FROM AUTHOR]