Alexander Grant Ruthven

Climate change is one of the main threats to biodiversity in the 21st century. However, the effects that it may have on different mammal species are unknown, making it difficult to implement conservation strategies. In this paper, we used species distribution models (SDM) to assess the effect of global climate change on the potential distribution of the 8 of the 9 marsupial species in Mexico, and analyzed their distribution in the current system of natural protected areas (NPAs). We used presence records for each species and bioclimatic variables from the present and the future (2050 and 2080) with 2 contrasting possible scenarios (representative concentration pathways RCP 4.5 and 8.5). We found that Tlacuatzin canescens would have the most stable potential range under any climate change scenario, while the remaining species (Caluromys derbianus, Chironectes minimus, Didelphis marsupialis, D. virginiana, Philander opossum, Marmosa mexicana, and Metachirus nudicaudatus) would undergo notable range losses in the future, though there would not only be losses—according to our SDMs, for all species there would be some range gain under the different climate scenarios, assuming the vegetation cover remained. The current system of NPAs in Mexico currently protects and under the 2 future scenarios would protect less than 20% of the potential range of marsupials, so a reevaluation of their areas beyond the NPAs is highly recommended for the long-term conservation of this group. Our results provide relevant information on the estimated effects of global climate change on marsupials, allowing us to design more effective methodologies for the protection of this portion of the mammalian fauna in Mexico.

Extant neosuchian crocodiles are represented by only 24 taxa that are confined to the tropics and subtropics. However, at other intervals during their 200 Myr evolutionary history the clade reached considerably higher levels of species-richness, matched by more widespread distributions. Neosuchians have occupied numerous habitats and niches, ranging from dwarf riverine forms to large marine predators. Despite numerous previous studies, several unsolved questions remain with respect to their biogeographic history, including the geographical origins of major groups, e.g. Eusuchia and Neosuchia itself. We carried out the most comprehensive biogeographic analysis of Neosuchia to date, based on a multivariate K-means clustering approach followed by the application of two ancestral area estimation methods (BioGeoBEARS and Bayesian ancestral location estimation) applied to two recently published phylogenies. Our results place the origin of Neosuchia in northwestern Pangaea, with subsequent radiations into Gondwana. Eusuchia probably emerged in the European archipelago during the Late Jurassic/Early Cretaceous, followed by dispersals to the North American and Asian landmasses. We show that putative transoceanic dispersal events are statistically significantly less likely to happen in alligatoroids. This finding is consistent with the saltwater intolerant physiology of extant alligatoroids, bolstering inferences of such intolerance in their ancestral lineages.

Background Carnivore mammals are animals vulnerable to human interference, such as climate change and deforestation. Their distribution and persistence are affected by such impacts, mainly in tropical regions such as the Amazon. Due to the importance of carnivores in the maintenance and functioning of the ecosystem, they are extremely important animals for conservation. We evaluated the impact of climate change on the geographic distribution of carnivores in the Amazon using Species Distribution Models (SDMs). Do we seek to answer the following questions: (1) What is the effect of climate change on the distribution of carnivores in the Amazon? (2) Will carnivore species lose or gain representation within the Protected Areas (PAs) of the Amazon in the future? Methods We evaluated the distribution area of 16 species of carnivores mammals in the Amazon, based on two future climate scenarios (RCP 4.5 and RCP 8.5) for the year 2070. For the construction of the SDMs we used bioclimatic and vegetation cover variables (land type). Based on these models, we calculated the area loss and climate suitability of the species, as well as the effectiveness of the protected areas inserted in the Amazon. We estimated the effectiveness of PAs on the individual persistence of carnivores in the future, for this, we used the SDMs to perform the gap analysis. Finally, we analyze the effectiveness of PAs in protecting taxonomic richness in future scenarios. Results The SDMs showed satisfactory predictive performance, with Jaccard values above 0.85 and AUC above 0.91 for all species. In the present and for the future climate scenarios, we observe a reduction of potencial distribution in both future scenarios (RCP4.5 and RCP8.5), where five species will be negatively affected by climate change in the RCP 4.5 future scenario and eight in the RCP 8.5 scenario. The remaining species stay stable in terms of total area. All species in the study showed a loss of climatic suitability. Some species lost almost all climatic suitability in the RCP 8.5 scenario. According to the GAP analysis, all species are protected within the PAs both in the current scenario and in both future climate scenarios. From the null models, we found that in all climate scenarios, the PAs are not efficient in protecting species richness.

Biological invasion is one serious threat to global biodiversity, economics and sustainability. Under the era of globalization, emerging non-native species are still accelerating at an unprecedented rate. Identifying new field records of non-native species at early stages is critically important to develop effective prevention and management schemes. Here, we conducted field surveys and applied genetic analysis to identify new recordings of non-native amphibians in Shenzhen (a megacity of South China with enormous trade volume). We recorded a total of three non-native amphibians (Ceratophrys ornata, Hoplobatrachus rugulosus and Eleutherodactylus planirostris) in the field with two having establishment evidence (H. rugulosus and E. planirostris). Further ecological niche modeling based on climatic and habitat variables also detected a high habitat suitability of the two species with field establishment evidence and a low habitat suitability for the other three species (C. ornata, Rana catesbeiana and Xenopus laevis) lacking establishment evidence or field observation with only records in the market and database. We recommend more systematic surveys covering wider areas to investigate the establishment of non-native amphibians to stop their further invasions in China.

Ongoing climate change has caused well‐documented displacements of species' geographic distribution to newly climatically suitable areas. Ecological niche models (ENM) are widely used to project such climate‐induced changes but typically ignore species' interspecific interactions that might facilitate or prevent its establishment in new areas. Here, we projected the change in the distribution of Juçara Palm (Euterpe edulis Mart., Arecaceae), a neotropical threatened palm, taking into consideration its ecological interactions. We run ENMs of E. edulis, plus its known seed dispersers (15 bird species) and predators (19 birds and mammals) under current and future climatic conditions. Additionally, for E. edulis, we removed deforested areas from the model. When considering only climate, climate change has a positive impact on E. edulis, with a predicted westward expansion and a modest southward contraction, with a 26% net gain in distribution by 2060. When removing deforested areas, however, climate change harms E. edulis, with a 66% predicted net distribution loss. Within the palm's distribution in this more realistic model, there is also a predicted reduction in the richness of its dispersers and predators. We conclude that the possible benefits of climate change to E. edulis' distribution are overshadowed by widespread habitat loss, and that global change is likely to disrupt some of its ecological interactions. The outcome of the interplay between the negative impact of the loss of dispersers, and the benefit of the loss of predators, is unclear, but the large contraction of E. edulis' range predicted here foresees a dim future for the species.

This paper presents the original data on studies of populations of guppies on the territory of Ukraine on the example of those of them surviving for many years in the drainage system of Kyiv. For 10 years, wild populations of guppies and their morphological features were studied in the warm water flows of the Bortnychi aeration station in Kyiv (2011–2020). During this period, the original “key” was developed to describe the morphology of their coloration peculiarities, which includes: total length, the number of pattern and coloration elements (4 types, 9 elements), pigmented area (light — orange, dark, pigmentation index), the shape and pigmentation of the tail (6 types) and its asymmetry At present, in the countries of Eastern Europe, the species is not adapted to any waters in the wild due to low winter temperatures, but these fish have become well established in sewage and other warm water bodies in urbanized areas (cities, towns, factories, etc.). We described the places where this invasive species had been found for many years, highlighting its key features. Thanks to GIS modelling, it was revealed that the existence of wild populations of guppies in Ukraine and Latvia is possible only in warm waters (currently mainly sewage systems of big cities) within anthropogenic territories. Such a key and study of relatively isolated populations of invasive species will provide a deeper understanding of micro-evolution of their morphological features (coloration) in isolation, help to track distribution of invasive species in a changing climate and provide material for comparison with possible similar invasions in areas heavily affected by military actions.

Animals that frequently encounter toxins often develop mechanisms of toxin resistance over evolutionary time. Both predators that consume toxic prey and organisms in physical contact with a toxin in their environment may experience natural selection for resistance. Based on observations that Pacific Chorus Frogs (Pseudacris regilla) sometimes eat and mistakenly amplect tetrodotoxin (TTX)-defended Taricha newts, we predicted that P. regilla may possess TTX resistance. We compared amino acid sequences of domain IV of the muscle voltage-gated sodium channel gene SCN4A (NaV1.4) in populations of P. regilla that are sympatric and allopatric with Taricha. We identified a single substitution in NaV1.4 of P. regilla at a conserved site in the pore loop where TTX binds. Although the role of this site in TTX resistance has not been functionally assessed, both allopatric and sympatric P. regilla had this substitution, along with several other reptiles and amphibians, suggesting that it may be unrelated to TTX exposure from Taricha. Thus, there is no conclusive evidence that P. regilla possesses TTX resistance encoded by amino acid substitutions in this domain. California occurrence data from the last 50 yr indicate that Taricha activity peaks in January while the activity of P. regilla peaks in April, with times where the species may come into contact. However, P. regilla may not be exposed to levels of TTX from Taricha high enough to select for mutations in NaV1.4. Other unidentified mechanisms of TTX resistance could be present in P. regilla and other species sympatric with toxic newts.

Largemouth Bass (Micropterus salmoides, LMB) and Smallmouth Bass (Micropterus dolomieu, SMB) are among the most highly invasive species across the globe, but are simultaneously among the most highly sought-after game fish. To explain these disparate views, data on invasive status and angling participation of these two species were compiled at the country level. Largemouth Bass were found established in 62 countries on five continents, whereas SMB were found established in only nine countries on the same five continents. Invasive risk assessments were disparate between the species, with more for SMB (N = 29) than LMB (N = 27). In every instance save one (Finland), SMB were considered “invasive” compared to LMB, which were “invasive” in only 74% of assessments. Twenty-eight countries with non-native black bass have groups that participate in high-profile fishing tournament such the Black Bass World Championship, BASS (Bass Anglers Sportsmans Society) Nation, and Major League Fishing. Most countries with fishing tournaments occur in countries with established LMB populations than in countries with established SMB populations, suggesting a greater economic importance on LMB fishing. The struggle between conserving biodiversity and relying upon economic benefits from fishing for introduced species is a wicked problem likely to continue into the future.

The maintenance, restoration, and improvement of habitat structure are critical for biodiversity conservation. Under this context, studies assessing habitat connectivity become essential, especially those focused on anthropized regions holding high species richness. We calculated the habitat connectivity of four species of insectivorous bats with different dispersal capacity and habitat preferences in a highly anthropized region in central Mexico, Idionycteris phyllotis and Myotis thysanodes , with a high dispersal capacity and forest-dependency, and Eptesicus fuscus with a low dispersal capacity, and Tadarida brasiliensis with a high dispersal capacity, as the more tolerant bat species to anthropogenic disturbance. We developed niche-based species distribution models to identify suitable habitat patches for each species. We then assessed habitat connectivity and the importance of suitable habitat patches for maintaining connectivity using a graph theory approach. Our results showed that forest dependency was most important than dispersal capacity for connectivity. We also found that the Iztaccíhuatl-Popocatépetl mountain, a National Park comprising 4.2% of natural vegetation in the study area, was the most critical patch for maintaining connectivity for most of the study species. Our study demonstrates the importance of conserving the remnants of natural vegetation for maintaining habitat connectivity within a fragmented landscape and demonstrates the importance of conserving protected areas as well as other remnants of vegetation for the maintenance of habitat connectivity within a fragmented landscape.

Advances in technology have equipped paleobiologists with new analytical tools to assess the fossil record. The functional traits of vertebrates have been used to infer paleoenvironmental conditions. In Quaternary deposits, birds are the second-most-studied group after mammals. They are considered a poor paleoambiental proxy because their high vagility and phenotypic plasticity allow them to respond more effectively to climate change. Investigating multiple groups is important, but it is not often attempted. Biogeographical and climatic niche information concerning small mammals, reptiles, and birds have been used to infer the paleoclimatic conditions present during the Late Pleistocene at San Josecito Cave (~28,000 14C years BP), Mexico. Warmer and dryer conditions are inferred with respect to the present. The use of all of the groups of small vertebrates is recommended because they represent an assemblage of species that have gone through a series of environmental filters in the past. Individually, different vertebrate groups provide different paleoclimatic information. Birds are a good proxy for inferring paleoprecipitation but not paleotemperature. Together, reptiles and small mammals are a good proxy for inferring paleoprecipitation and paleotemperature, but reptiles alone are a bad proxy, and mammals alone are a good proxy for inferring paleotemperature and precipitation. The current paleoclimatic results coupled with those of a previous vegetation structure analysis indicate the presence of non-analog paleoenvironmental conditions during the Late Pleistocene in the San Josecito Cave area. This situation would explain the presence of a disharmonious fauna and the extinction of several taxa when these conditions later disappeared and do not reappear again.