Charles Frederick Hartt

Male frogs emit stereotypical advertisement calls to attract mates and deter conspecific rivals. The evolution of these calls is thought to be linked to anatomical constraints and the acoustic characteristics of their surroundings. The acoustic adaptation hypothesis (AAH) posits that species evolve calls that maximize propagation distance and reduce signal degradation in the environment where they are emitted. We applied phylogenetic comparative analyses to study the association of body size, vegetation density, type of aquatic ecosystem, and calling site on the evolution of acoustic traits in Cophomantini, a large radiation of Neotropical treefrogs (Hylidae). We obtained and analyzed body size, acoustic, and habitat data from a total of 112 species (58% of Cophomantini), using the most inclusive available phylogeny. We found a significant negative correlation between peak frequency, body size, and calling site, but contrary to the predictions of the AAH, we did not find support for associations among call traits and environmental characteristics. Although spectral allometry is explained by an anatomical constraint, it could also be maintained by female choice. We recommend that future studies strive to incorporate factors such as female mate preferences, eavesdropping by predators or parasites, and genetic drift.

Molossus molossus is a widely distributed neotropical bat species in the Americas, often found in urban areas. This study evaluated climate change effects on the potential geographic distribution of M. molossus, a natural host of zoonotic pathogens such as Orthohantavirus, in the Neotropical region. Using ecological niche modeling (ENM), models were generated for current (1970–2000) and future (2070) climate scenarios based on two Shared Socioeconomic Pathways (SSP2–4.5 and SSP5–8.5) and two Global Circulation Models (MPI-ESM1–2-LR and IPSL-CM6A-LR). Results indicated that in the current scenario, warm and coastal areas of the Neotropics are suitable for M. molossus occurrence. Risk areas for Orthohantavirus transmission were mapped by overlapping the probability of urban expansion with projections of climatic suitability for the bat. For both future scenarios (2070), projections indicate an expansion of suitable climatic areas for M. molossus over urban expansion zones, specifically in Brazil, Paraguay, Peru, Ecuador, Costa Rica, Honduras, El Salvador, Guatemala, Belize, Mexico, the United States, Cuba, Haiti, the Dominican Republic, and Puerto Rico. However, projections also indicate the Lesser Antilles under climate threat, considering that no climatic suitability areas will remain. These findings provide important information for planning surveillance and mitigation actions for zoonotic risks associated with M. molossus, considering climate change impacts on its geographic distribution in the Neotropical region.

Island ecosystems have significant conservation value owing to their higher endemic biotas. Moreover, studies of regional communities that compare differences in species composition (species dissimilarity) among islands and the mainland suggest that community assembly on islands is different from that on the mainland. However, the uniqueness of island biotic assembly has been little studied at the global scale, nor have phylogenetic information or alien species been considered in these patterns. We evaluate taxonomic and phylogenetic change from one community to the next, focusing on differences in species composition between mainland-mainland (M-M) pairs compared to differences between mainland-island pairs (M-I) and between island-island pairs (I-I), using herpetofauna on islands and adjacent mainland areas worldwide. Our analyses detect greater taxonomic and phylogenetic dissimilarity for M-I and I-I comparisons than predicted by M-M model, indicating different island herpetofauna assembly patterns compared with mainland counterparts across the world. However, this higher M-I dissimilarity has been significantly decreased after considering alien species. Our results provide global evidence on the importance of island biodiversity conservation from the aspect of both the taxonomic and phylogenetic uniqueness of island biotic assembly.

We assessed changes in fundamental climate‐niche space for lizard and snake species in western North America under modeled climate scenarios to inform natural resource managers of possible shifts in species distributions. We generated eight distribution models for each of 130 snake and lizard species in western North America under six time‐by‐climate scenarios. We combined the highest‐performing models per species into a single ensemble model for each scenario. Maps were generated from the ensemble models to depict climate‐niche space for each species and scenario. Patterns of species richness based on climate suitability and niche shifts were calculated from the projections at the scale of the entire study area and individual states and provinces, from Canada to Mexico. Squamate species' climate‐niche space for the recent‐time climate scenario and published known ranges were highly correlated (r = 0.81). Overall, reptile climate‐niche space was projected to move northward in the future. Sixty‐eight percent of species were projected to expand their current climate‐niche space rather than to shift, contract, or remain stable. Only 8.5% of species were projected to lose climate‐niche space in the future, and these species primarily occurred in Mexico and the southwestern U.S. We found few species were projected to lose all suitable climate‐niche space at the state or province level, although species were often predicted to occupy novel areas, such as at higher elevations. Most squamate species were projected to increase their climate‐niche space in future climate scenarios. As climate niches move northward, species are predicted to cross administrative borders, resulting in novel conservation issues for local landowners and natural resource agencies. However, information on species dispersal abilities, landscape connectivity, biophysical tolerances, and habitat suitability is needed to contextualize predictions relative to realized future niche expansions.

Coral reefs represent a source of ecosystem services relevant for the permanence of coastal human communities. Given the importance of zooxanthellate scleractinian corals (ZSC) in these ecosystems, information on the presence and distribution of this group is valuable for studying the biodiversity and establishing management strategies to ensure their permanence over time. Despite being a highly studied biological group in the Western Atlantic, records of ZSC presence are heterogeneous and are distributed mainly in the Caribbean Sea. One way to analyze the distribution of biota at large spatial scales is through biogeographic regionalizations. To identify the distribution patterns of ZSC in the Western Atlantic and propose a biogeographic regionalization based in this biological group, we performed a Parsimony Analysis of Endemism (PAE) at ecoregion scale using Species Distribution Models (SDM) to fill the gaps in data on the distribution of these corals. Through these analyses, we identified the presence of two main biogeographic provinces: Northwestern Atlantic Tropical Province and Tropical Southwestern Atlantic. According to Jaccard Index, this regionalization is highly similar to those performed with multitaxa by other authors, which demonstrates that for these purposes this taxa can be considered as a surrogate group. In terms of management, this study highlights the importance of establishing preservation and conservation measures that address this biological group, in order to guarantee both the permanence of other taxa and the ecosystem goods and services they provide.

Understanding the distribution of rare species is important for conservation prioritisation. Traditionally, museums and other research institutions have served as depositories for specimens and biodiversity information. However, estimating abundance from these sources is challenging due to spatiotemporally biased collection methods. For instance, large‐bodied reptiles that are found near research institutions or in popular, easily accessible sites tend to be overrepresented in collections compared to smaller species found in remote areas. Recently, a substantial number of observations have been amassed through citizen (or community) science initiatives, which are invaluable for monitoring purposes. Given the unstructured nature of this sampling, these datasets are often affected by biases, such as taxonomic, spatial and temporal preferences. Therefore, analysing data from these two sources can lead to different abundance estimates. This study compiled data on Brazilian reptile species from the Global Information Biodiversity Facility (GBIF). It employed a community‐ecology approach to analyse data from research institutions and citizen science initiatives, separately and collectively, to assess taxonomic and spatial species coverage and predict species rarity. Using a 1‐degree hexagonal grid, we analysed the spatial distribution of reptile communities and calculated rarity indices for 754 reptile species. Our findings reveal that 87 species were exclusively recorded in the citizen science subset, while 212 were recorded only by research institutions. The number of observations per species in the citizen science data followed a Gambin distribution, which aligns with the expected pattern of abundance in natural communities, unlike the data from research institutions. This suggests that citizen science data may be a more accurate source for estimating species abundance and rarity. The discrepancies in rarity classifications between the datasets were likely due to differences in sample size and potentially other sampling parameters. Nevertheless, combining data collected by both research institutions and citizen science initiatives can help to fill knowledge gaps in reptile species occurrence, thus enhancing the foundation for conservation efforts on a national scale.

Gregory’s diverticulum, a digestive tract structure unique to a derived group of sand dollars (Echinoidea: Scutelliformes), is filled with sand grains obtained from the substrate the animals inhabit. The simple methods of shining a bright light through a specimen or testing response to a magnet can reveal the presence of a mineral-filled diverticulum. Heavy minerals with a specific gravity of >2.9 g/cm3 are selectively concentrated inside the organ, usually at concentrations one order of magnitude, or more, greater than found in the substrate. Analyses of diverticulum content for thirteen species from nine genera, using optical mineralogy, powder X-ray diffraction, scanning electron microscopy and energy dispersive X-ray spectroscopy, as well as micro-computed tomography shows the preference for selection of five major heavy minerals: magnetite (Fe3O4), hematite (Fe2O3), ilmenite (FeTiO3), rutile (TiO2), and zircon (ZrSiO4). Minor amounts of heavy or marginally heavy amphibole, pyroxene and garnet mineral grains may also be incorporated. In general, the animals exhibit a preference for mineral grains with a specific gravity of >4.0 g/cm3, although the choice is opportunistic and the actual mix of mineral species depends on the mineral composition of the substrate. The animals also select for grain size, with mineral grains generally in the range of 50 to 150 μm, and do not appear to alter this preference during ontogeny. A comparison of analytical methods demonstrates that X-ray attenuation measured using micro-computed tomography is a reliable non-destructive method for heavy mineral quantification when supported by associated analyses of mineral grains extracted destructively from specimens or from substrate collected together with the specimens. Commonalities in the electro-chemical surface properties of the ingested minerals suggest that such characteristics play an important role in the selection process.

Here, we used distribution models to predict the size of the environmentally suitable area for shrimps of fishing interest that were impacted by the tailing plume from the collapse of the Fundão Dam, one of the largest ecological disasters ever to occur in Brazil. Species distribution models (SDMs) were generated for nine species of penaeid shrimp that occurred in the impacted region. Average temperature showed the highest percentage of contribution for SDMs. The environmental suitability of penaeids varied significantly in relation to the distance to the coast and mouth river. The area of environmental suitability of shrimps impacted by tailings plumes ranged from 27 to 47 %. Notably, three protected areas displayed suitable conditions, before the disaster, for until eight species. The results obtained by the SDMs approach provide crucial information for conservation and restoration efforts of coastal biodiversity in an impacted region with limited prior knowledge about biodiversity distribution.

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.