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Ecke, F., B. A. Han, B. Hörnfeldt, H. Khalil, M. Magnusson, N. J. Singh, and R. S. Ostfeld. 2022. Population fluctuations and synanthropy explain transmission risk in rodent-borne zoonoses. Nature Communications 13. https://doi.org/10.1038/s41467-022-35273-7
Population fluctuations are widespread across the animal kingdom, especially in the order Rodentia, which includes many globally important reservoir species for zoonotic pathogens. The implications of these fluctuations for zoonotic spillover remain poorly understood. Here, we report a global empirical analysis of data describing the linkages between habitat use, population fluctuations and zoonotic reservoir status in rodents. Our quantitative synthesis is based on data collated from papers and databases. We show that the magnitude of population fluctuations combined with species’ synanthropy and degree of human exploitation together distinguish most rodent reservoirs at a global scale, a result that was consistent across all pathogen types and pathogen transmission modes. Our spatial analyses identified hotspots of high transmission risk, including regions where reservoir species dominate the rodent community. Beyond rodents, these generalities inform our understanding of how natural and anthropogenic factors interact to increase the risk of zoonotic spillover in a rapidly changing world. Many rodent species are known as hosts of zoonotic pathogens, but the ecological conditions that trigger spillover are not well-understood. Here, the authors show that population fluctuations and association with human-dominated habitats explain the zoonotic reservoir status of rodents globally.
[NO TITLE AVAILABLE] https://doi.org/10.2994/sajh-d-20-00051
Climate change is a global phenomenon that will generate profound changes in biodiversity in the near future. Studies have reported negative impacts of climate change for South American amphibians; however, for Andean species such as Rhinella spinulosa, the potential response to the effects of climate change is unknown. Using ecological niche models, we estimate the potential distribution of R. spinulosa, identifying the environmental variables that explain its distribution and projecting predictions in climate change scenarios to elucidate their impact on the distribution pattern. The results revealed that the variables of elevation (48.7%), mean temperature of the hottest quarter (44.2%), and topographic humidity index (3.2%) were the most important contributors to the model and are predictors of the distribution of R. spinulosa. The most suitable areas for its distribution are its current range, extending to the north, as well as on the western Andean slope and Argentine Patagonia. Predictions for the future (year 2080) under two scenarios (benign and severe) coincide with the distribution predicted for the current one. Climatic conditions will not be considerably different in the distribution area of R. spinulosa, which may be due to the buffer effect of the mountain range. However, freshwater ecosystems will be more at risk from climate change, which could affect the reproductive success and survival of amphibians. Therefore, we recommend evaluating water availability at a local scale to understand the potential changes in the geographic distribution of R. spinulosa.
Oliveira-Dalland, L. G., L. R. V. Alencar, L. R. Tambosi, P. A. Carrasco, R. M. Rautsaw, J. Sigala-Rodriguez, G. Scrocchi, and M. Martins. 2022. Conservation gaps for Neotropical vipers: Mismatches between protected areas, species richness and evolutionary distinctiveness. Biological Conservation 275: 109750. https://doi.org/10.1016/j.biocon.2022.109750
The continuous decline in biodiversity despite global efforts to create new protected areas calls into question the effectiveness of these areas in conserving biodiversity. Numerous habitats are absent from the global protected area network, and certain taxonomic groups are not being included in conservation planning. Here, we analyzed the level of protection that the current protected area system provides to viper species in the Neotropical region through a conservation gap analysis. We used distribution size and degree of threat to set species-specific conservation goals for 123 viper species in the form of minimum percentage of their distribution that should be covered by protected areas, and assessed the level of protection provided for each species by overlapping their distribution with protected areas of strict protection. Furthermore, using species richness and evolutionary distinctiveness as priority indicators, we conducted a spatial association analysis to detect areas of special concern. We found that most viper species have <1/4 of their distribution covered by protected areas, including 22 threatened species. Also, the large majority of cells containing high levels of species richness were significantly absent from protected areas, while evolutionary distinctiveness was particularly unprotected in regions with relatively low species richness, like northern Mexico and the Argentinian dry Chaco. Our results provide further evidence that vipers are largely being excluded from conservation planning, leaving them exposed to serious threats that can lead to population decline and ultimately extinction.
Castaño-Quintero, S. M., J. Escobar-Luján, F. Villalobos, L. M. Ochoa-Ochoa, and C. Yáñez-Arenas. 2022. Amphibian Diversity of the Yucatan Peninsula: Representation in Protected Areas and Climate Change Impacts. Diversity 14: 813. https://doi.org/10.3390/d14100813
Knowledge about the dynamics of regional diversity patterns is a foundation on which measures aimed to protect diversity dimensions in the light of climate change can be constructed. Here, we describe taxonomic, phylogenetic, and functional diversity patterns of amphibians in the Yucatan Peninsula and their representation in the current protected area system. We stacked current and future potential distribution models to estimate taxonomic diversity and, based on the most recent amphibian phylogeny and nine functional traits, we measured phylogenetic and functional diversity. Independent phylogenetic and functional metrics were obtained by applying null models that allowed us to identify the presumably signature mechanisms underlying assemblage formation. We evaluated the effectiveness of the protected areas in protecting diversity dimensions across scenarios. We found phylogenetic and functional clustering as a result of environmental filters that have allowed only recently diverged species with converged functional traits to establish. Nevertheless, random assemblages are more widespread possibly due to the opposite directions in which competition and environmental filtering are acting. Overall, a decrease in all diversity dimensions is projected under future climate change scenarios compared with the current time. None of the protected areas evaluated were effective in protecting diversity dimensions, stressing the need to complete the existing protected areas network.
Sánchez-González, L. A., H. Cayetano, D. A. Prieto-Torres, O. R. Rojas-Soto, and A. G. Navarro-Sigüenza. 2022. The role of ecological and geographical drivers of lineage diversification in the Squirrel cuckoo Piaya cayana in Mexico: a mitochondrial DNA perspective. Journal of Ornithology. https://doi.org/10.1007/s10336-022-02008-w
The Squirrel Cuckoo ( Piaya cayana ) is a widely distributed neotropical species with 14 recognized subspecies. Two parapatric subspecies are distributed in Mexico. P. c. mexicana is endemic to the seasonally dry tropical forests of western Mexico, and P. c. thermophila is found in humid forests from eastern Mexico to western Colombia. The 2 taxa have a small area of overlap on the Isthmus of Tehuantepec, but there is pronounced phenotypic differentiation, and very few reported intermediate individuals between these forms, leading to debate about the taxonomic status of the Mesoamerican taxa. Based on two mitochondrial genes, we used phylogenetic, phylogeographic, morphological, and ecological modelling analyses to describe the evolutionary relationships and paleo-distributional patterns of P. cayana in Mexico. Divergence time estimates suggest that the split between P. c. mexicana and P. c. thermophila occurred during the Pleistocene, about 1.24 Mya. Morphometrics of Mexican subspecies indicate that tail length and the white tail tips are significantly longer in P. c. mexicana , while P. c. thermophila has a longer and wider bill. Ecological niche analyses indicated that niche similarity between both lineages was lower than expected by chance, while low values on cross-prediction tests suggested that the two lineages have inhabited different environmental spaces since at least the Late Pleistocene. The ecological niche difference may also be associated with a steep humidity gradient, suggesting a significant contemporary environmental barrier. Overall, our results indicate that P. c. mexicana and P. c. thermophila have divergent evolutionary histories; therefore, the current taxonomic status of the Piaya populations in Mexico reflects neither their evolutionary relationships nor their apparent divergence. Our results suggest a major split in the polytypic P. cayana coinciding with the Andes, suggesting that the western endemic P. c. mexicana and P. c. thermophila are best treated as separate species-level taxa . Die Rolle ökologischer und geografischer Faktoren bei der Abstammung und Diversifikation des Eichhornkuckucks Piaya cayana in Mexiko: von der mitochondrialen DNA her betrachtet Der Eichhornkuckuck ( Piaya cayana ) ist eine weit verbreitete neotropische Art mit 14 anerkannten Unterarten. In Mexiko gibt es zwei parapatrische Unterarten. P. c. mexicana ist in den je nach Jahreszeit trockenen tropischen Wäldern Westmexikos beheimatet, während P. c. thermophila in den feuchten Wäldern von Ostmexiko bis Westkolumbien vorkommt. Die beiden Taxa überschneiden sich in einem kleinen Gebiet an der Landenge von Tehuantepec, aber es gibt einen ausgeprägten phänotypischen Unterschied und nur sehr wenige bekannte Mischtypen zwischen den beiden und damit Anlass zu Diskussionen über den taxonomischen Status dieser mittelamerikanischen Taxa. Auf der Grundlage zweier mitochondrialer Gene haben wir phylogenetische, phylogeografische, morphologische und ökologische Modell-Analysen durchgeführt, um die abstammungsbiologischen Verbindungen und Verbreitungsmuster von P. cayana im Paläozän in Mexiko zu bestimmen. Schätzungen der Entstehungszeit der Unterschiede deuten darauf hin, dass die Trennung zwischen P. c. mexicana und P. c. thermophila während des Pleistozäns stattfand, vor etwa 1,24 Millionen Jahren. Die morphometrischen Daten der mexikanischen Unterarten zeigen, dass die Schwanzlänge und die weißen Schwanzspitzen bei P. c. mexicana deutlich länger sind, während P. c. thermophila einen längeren und breiteren Schnabel hat. Analysen der ökologischen Nischen zeigten, dass die Übereinstimmungen zwischen den beiden Linien geringer waren als durch Zufall zu erwarten wäre, während niedrige Werte bei Kreuz-Vorhersagetests darauf hindeuteten, dass die beiden Linien mindestens seit dem späten Pleistozän in unterschiedlichen Lebensräumen gelebt haben müssen. Der ökologische Nischenunterschied kann auch mit dem starken Feuchtigkeitsgradienten zusammenhängen, was auf eine bedeutende gegenwärtige Umweltbarriere hinweist. Insgesamt deuten unsere Ergebnisse darauf hin, dass P. c. mexicana und P. c. thermophila eine unterschiedliche Entwicklungsgeschichte haben; daher gibt der derzeitige taxonomische Status der Piaya-Populationen in Mexiko weder ihre evolutionäre Verwandtschaft, noch ihre offensichtlichen Unterschiede wieder. Unsere Ergebnisse deuten darauf hin, dass sich der polytypische P. cayana in den Anden aufgespalten hat, was bedeuten könnte, dass die im Westen endemischen P. c. mexicana und P. c. thermophila am besten als separate Taxa auf Artniveau behandelt werden sollten.
Rautsaw, R. M., G. Jiménez-Velázquez, E. P. Hofmann, L. R. V. Alencar, C. I. Grünwald, M. Martins, P. Carrasco, et al. 2022. VenomMaps: Updated species distribution maps and models for New World pitvipers (Viperidae: Crotalinae). Scientific Data 9. https://doi.org/10.1038/s41597-022-01323-4
Beyond providing critical information to biologists, species distributions are useful for naturalists, curious citizens, and applied disciplines including conservation planning and medical intervention. Venomous snakes are one group that highlight the importance of having accurate information given their cosmopolitan distribution and medical significance. Envenomation by snakebite is considered a neglected tropical disease by the World Health Organization and venomous snake distributions are used to assess vulnerability to snakebite based on species occurrence and antivenom/healthcare accessibility. However, recent studies highlighted the need for updated fine-scale distributions of venomous snakes. Pitvipers (Viperidae: Crotalinae) are responsible for >98% of snakebites in the New World. Therefore, to begin to address the need for updated fine-scale distributions, we created VenomMaps, a database and web application containing updated distribution maps and species distribution models for all species of New World pitvipers. With these distributions, biologists can better understand the biogeography and conservation status of this group, researchers can better assess vulnerability to snakebite, and medical professionals can easily discern species found in their area. Measurement(s) Species Distributions Technology Type(s) Geographic Information System • Species Distribution Model (MaxEnt/kuenm) Factor Type(s) Occurrence Records • Environmental Data Sample Characteristic - Organism Crotalinae Sample Characteristic - Location North America • South America
Mantintsilili, A., N. Shivambu, T. C. Shivambu, and C. T. Downs. 2022. Online and pet stores as sources of trade for reptiles in South Africa. Journal for Nature Conservation 67: 126154. https://doi.org/10.1016/j.jnc.2022.126154
The ever-increasing human population, globalisation, and desire to keep pets have resulted in the translocation of many species into non-native environments. As a result, some of the non-native reptile species have been introduced to South Africa through the pet trade. However, little is known about…
Méndez-Camacho, K., O. Leon-Alvarado, and D. R. Miranda-Esquivel. 2021. Biogeographic evidence supports the Old Amazon hypothesis for the formation of the Amazon fluvial system. PeerJ 9: e12533. https://doi.org/10.7717/peerj.12533
The Amazon has high biodiversity, which has been attributed to different geological events such as the formation of rivers. The Old and Young Amazon hypotheses have been proposed regarding the date of the formation of the Amazon basin. Different studies of historical biogeography support the Young A…
Boyd, R. J., G. D. Powney, C. Carvell, and O. L. Pescott. 2021. occAssess: An R package for assessing potential biases in species occurrence data. Ecology and Evolution 11: 16177–16187. https://doi.org/10.1002/ece3.8299
Species occurrence records from a variety of sources are increasingly aggregated into heterogeneous databases and made available to ecologists for immediate analytical use. However, these data are typically biased, i.e. they are not a probability sample of the target population of interest, meaning …
Armijos-Ojeda, D., D. Székely, P. Székely, D. Cogălniceanu, D. F. Cisneros-Heredia, L. Ordóñez-Delgado, A. Escudero, and C. I. Espinosa. 2021. Amphibians of the equatorial seasonally dry forests of Ecuador and Peru. ZooKeys 1063: 23–48. https://doi.org/10.3897/zookeys.1063.69580
Seasonally dry forests (SDFs) are one of the most challenging ecosystems for amphibians, fueling the diversity of this group of vertebrates. An updated inventory of native amphibians present in the Equatorial SDF is provided, which extends along the Pacific coast of Ecuador and northwestern Peru. Th…