A Review of Mammarenaviruses and Rodent Reservoirs in the Americas.

In the Americas, infectious viral diseases caused by viruses of the genus Mammarenavirus have been reported since the 1960s. Such diseases have commonly been associated with land use changes, which favor abundance of generalist rodent species. In the Americas-where the rates of land use change are among the highest worldwide-at least 1326 of all 2277 known rodent species have been reported. We conducted a literature review of studies between 1960 and 2020, to establish the current and historical knowledge about genotypes of mammarenaviruses and their rodent reservoirs in the Americas. Our overall goal was to show the importance of focusing research efforts on the American continent, since the conditions exist for future viral hemorrhagic fever (VHF) outbreaks caused by rodent-borne viruses, in turn, carried by widely distributed rodents. We found 47 species identified down to the species level, and one species identified only down to the genus level (Oryzomys sp.), reported in the Americas as reservoirs of mammarenaviruses, most these are ecological generalists. These species associate with 29 genotypes of Mammarenavirus, seven of which have been linked to VHFs in humans. We also highlight the need to monitor these species, in order to prevent viral disease outbreaks in the region.

Causes and consequences of change rates in the habitat of the threatened tropical porcupine, Sphiggurus mexicanus (Rodentia: Erethizontidae) in Oaxaca, Mexico: implications for its conservation / Causas y consecuencias de las tasas de cambio en el hábitat del puerco espín tropical amenazado, Sphiggurus mexicanus (Rodentia: Erethizontidae), en Oaxaca, México: implicaciones para su conservación

Land use changes by human activities have been the main causes of habitats and wildlife population degradation. In the Tehuantepec Isthmus in Oaxaca, the tropical habitat of the porcupine Sphiggurus mexicanus has been subject to vegetation and land use changes, causing its reduction and fragmentation. In this study, we estimated vegetation cover and land use (δn) change rates and assessed habitat availability and potential corridors for possible porcupine movements to avoid its isolation. In the study area, the type of vegetation with the most change rate value was the savanna (δn=-2.9), transformed into induced grasslands. Additionally, we have observed the porcupine (since 2011) in semi-deciduous (δn=-0.87) and tropical dry (δn=-0.89) forests that have been transformed in temporal agriculture and mesquite and induced grasslands. The vegetation inhabited by the porcupine resulted in recording a total of 64 plant species (44 trees, nine vines, seven herbs, four shrubs), of which the vine Bunchosia lanceolata showed the highest importance value (41.85) followed by the trees Guazuma ulmifolia (22.71), Dalbergia glabra (18.05), and Enterolobium cyclocarpum (17.02). The habitat evaluation and potential corridor analysis showed that only 1 501.93ha could be considered as suitable habitats with optimum structural conditions (coverage, surface, and distances to transformed areas) to maintain viable populations of S. mexicanus, and 293.6ha as corridors. An increasing destruction of the porcupines’ habitat has been observed in the study area due to excessive logging, and actions for this species and its habitat conservation and management have to be taken urgently. Rev. Biol. Trop. 62 (4): 1481-1494. Epub 2014 December 01.

Los cambios de uso del suelo por actividades humanas, han sido de las principales causas de la degradación, reducción y fragmentación de los hábitats y poblaciones de fauna silvestre. En el Istmo de Tehuantepec, Oaxaca, el hábitat del puercoespín tropical Sphiggurus mexicanus, se encuentra sometido a cambios de cobertura vegetal y uso del suelo, que están causando la reducción y fragmentación de su hábitat. Debido a ello, estimamos las tasas de cambio de la cobertura vegetal y uso del suelo (δn), y evaluamos la disponibilidad del hábitat y de corredores vegetales potenciales para los posibles movimientos del puercoespín tropical y evitar su aislamiento. En el área de estudio el tipo de vegetación con mayor valor de tasa de cambio fue la sabana (δn=-2.9), transformado en pastizal inducido. Adicionalmente, observamos puercoespínes (desde 2011) en selva mediana subperennifolia (δn=-0.87) y selva baja caducifolia (δn=-0.89), los cuales han sido transformados en áreas de cultivo, selva baja espinosa y pastizal inducido. Caracterizamos la vegetación del hábitat del puercoespín, registrando un total de 64 especies vegetales (44 árboles, nueve bejucos, siete hierbas y cuatro arbustos), de los cuales, el bejuco Bunchosia lanceolata, presentó los valores más altos de importancia (41.85), seguidos por los árboles Guazuma ulmifolia (22.71), Dalbergia glabra (18.05), y Enterolobium cyclocarpum (17.02). El análisis de evaluación de hábitat y corredores potenciales mostró que solo 1 501.93ha pueden considerarse como hábitats adecuados con condiciones estructurales (de cobertura, superficie y distancias a áreas transformadas) para mantener poblaciones viables de S. mexicanus; y 293.6ha como corredores. La destrucción del hábitat del puerco espín en el área de estudio está incrementándose por la tala excesiva, por lo tanto, es prioritario emprender acciones para la conservación y manejo del taxón y su hábitat.

Causes and consequences of change rates in the habitat of the threatened tropical porcupine, Sphiggurus mexicanus (Rodentia: Erethizontidae) in Oaxaca, Mexico: implications for its conservation.

Land use changes by human activities have been the main causes of habitats and wildlife population degradation. In the Tehuantepec Isthmus in Oaxaca, the tropical habitat of the porcupine Sphiggurus mexicanus has been subject to vegetation and land use changes, causing its reduction and fragmentation. In this study, we estimated vegetation cover and land use (δn) change rates and assessed habitat availability and potential cor- ridors for possible porcupine movements to avoid its isolation. In the study area, the type of vegetation with the most change rate value was the savanna (δn = -2.9), transformed into induced grasslands. Additionally, we have observed the porcupine (since 2011) in semi-deciduous (δn = -0.87) and tropical dry (δn = -0.89) forests that have been transformed in temporal agriculture and mesquite and induced grasslands. The vegetation inhabited by the porcupine resulted in recording a total of 64 plant species (44 trees, nine vines, seven herbs, four shrubs), of which the vine Bunchosia lanceolata showed the highest importance value (41.85) followed by the trees Guazuma ulmifolia (22.71), Dalbergia glabra (18.05), and Enterolobium cyclocarpum (17.02). The habitat evaluation and potential corridor analysis showed that only 1 501.93ha could be considered as suitable habitats with optimum structural conditions (coverage, surface, and distances to transformed areas) to maintain viable populations of S. mexicanus, and 293.6 ha as corridors. An increasing destruction of the porcupines' habitat has been observed in the study area due to excessive logging, and actions for this species and its habitat conserva- tion and management have to be taken urgently.

Negative impacts of human land use on dung beetle functional diversity.

The loss of biodiversity caused by human activity is assumed to alter ecosystem functioning. However our understanding of the magnitude of the effect of these changes on functional diversity and their impact on the dynamics of ecological processes is still limited. We analyzed the functional diversity of copro-necrophagous beetles under different conditions of land use in three Mexican biosphere reserves. In Montes Azules pastures, forest fragments and continuous rainforest were analyzed, in Los Tuxtlas rainforest fragments of different sizes were analyzed and in Barranca de Metztitlán two types of xerophile scrub with different degrees of disturbance from grazing were analyzed. We assigned dung beetle species to functional groups based on food relocation, beetle size, daily activity period and food preferences, and as measures of functional diversity we used estimates based on multivariate methods. In Montes Azules functional richness was lower in the pastures than in continuous rainforest and rainforest fragments, but fragments and continuous forest include functionally redundant species. In small rainforest fragments (<5 ha) in Los Tuxtlas, dung beetle functional richness was lower than in large rainforest fragments (>20 ha). Functional evenness and functional dispersion did not vary among habitat types or fragment size in these reserves. In contrast, in Metztitlán, functional richness and functional dispersion were different among the vegetation types, but differences were not related to the degree of disturbance by grazing. More redundant species were found in submontane than in crassicaule scrub. For the first time, a decrease in the functional diversity in communities of copro-necrophagous beetles resulting from changes in land use is documented, the potential implications for ecosystem functioning are discussed and a series of variables that could improve the evaluation of functional diversity for this biological group is proposed.