Experimental evidence for reduced rodent diversity causing increased hantavirus prevalence.

Emerging and re-emerging infectious diseases have become a major global environmental problem with important public health, economic, and political consequences. The etiologic agents of most emerging infectious diseases are zoonotic, and anthropogenic environmental changes that affect wildlife communities are increasingly implicated in disease emergence and spread. Although increased disease incidence has been correlated with biodiversity loss for several zoonoses, experimental tests in these systems are lacking. We manipulated small-mammal biodiversity by removing non-reservoir species in replicated field plots in Panama, where zoonotic hantaviruses are endemic. Both infection prevalence of hantaviruses in wild reservoir (rodent) populations and reservoir population density increased where small-mammal species diversity was reduced. Regardless of other variables that affect the prevalence of directly transmitted infections in natural communities, high biodiversity is important in reducing transmission of zoonotic pathogens among wildlife hosts. Our results have wide applications in both conservation biology and infectious disease management.

The effect of habitat fragmentation and species diversity loss on hantavirus prevalence in Panama.

Habitat fragmentation and diversity loss due to increased conversion of natural habitats to agricultural uses influence the distribution and abundance of wildlife species and thus may change the ecology of pathogen transmission. We used hantaviruses in Panama as a research model to determine whether anthropogenic environmental change is associated with changes in the dynamics of viral transmission. Specifically, we wanted to determine whether hantavirus infection was correlated with spatial attributes of the landscape at both large and small scales or whether these changes are mediated by changes in community composition. When analyzed at coarse spatial scales, hantavirus reservoirs were more commonly found in disturbed habitats and edge habitats than in forested areas. At local scales, reservoir species dominance was significantly correlated with the slope of the terrain. To evaluate the effect of small-mammal diversity loss on infection dynamics, we implemented an experiment with selective species removal at experimental sites. Seroprevalence of hantavirus was higher in the community of small mammals and increased through time in the experimental sites. The higher seroprevalence in experimental plots suggests that greater diversity likely reduces encounter rates between infected and susceptible hosts. Our studies suggest that habitat loss and fragmentation and species diversity loss are altering hantavirus infection dynamics in Panama. Our work represents a multidisciplinary approach toward disease research that includes biodiversity concerns such as environmental change and degradation, human settlement patterns, and the ecology of host and nonhost species, work that may be especially important in tropical countries.

Modeling hantavirus reservoir species dominance in high seroprevalence areas on the Azuero Peninsula of Panama.

Habitat fragmentation commonly influences distribution of zoonotic disease reservoirs. In Panama, populations of rodent hosts of hantaviruses are favored by small habitat fragments isolated by agricultural lands. We expected a similar relationship between landscape characteristics and host distribution at fine geographical scales in southern Panama. The relative abundance of Zygodontomys brevicauda, the primary host for "Calabazo" virus, and other rodents was assessed at 24 sites within the Azuero Peninsula. We used satellite imagery to produce several spatial variables that described landscape; however, only slope was consistently related to abundances of the two most dominant rodent species. Using regression, we constructed a spatial model of areas of Z. brevicauda dominance, which in turn relates to higher infection rates. The model predicts highest abundances of Z. brevicauda in flat areas, where humans also dominate. These predictions have important ecological and conservation implications that associate diversity loss, topography, and human land use.

Diversidad, historia natural y conservación de los mamíferos de San Vito de Coto Brus, Costa Rica / Diversity, natural history and conservation of mammals from San Vito de Coto Brus, Costa Rica

Although Costa Rica has been biologically well studied,few areas have complete mammal inventories, which are essential for ecological studies and conservation. The San Vito region is considered among the most important for scientific research in the country because of the presence of the Wilson Botanical Garden and Las Cruces. However, the knowledge of its mammalian fauna is incomplete. We extensively studied the mammals of San Vito, compiled a checklist, and evaluated its composition, relative abundance, habitat distribution, and conservation status. We recorded 105 species, representing 85 genera, 29 families, and 10 orders. Non-volant mammals represented 62 species, 59 genera, 23 families, and 9 orders. Bats belonged to 6 families, 26 genera and 43 species. The extensive deforestation and hunting have caused the extinction of seven species, but the region still supports, surprisingly, a relatively high number of species, most of which are rare. Few species are common and abundant. Species richness was higher in forest, and forest fragments; fewer species were found in coffee plantations,induced grasslands, and secondary vegetation. Around 21% (13 species) are included in the IUCN red book. Three species are considered endangered (Saimiri oerstedii, Tapirus bairdii, and Sylvilagus dicei), and two threatened (Myrmecophaga trydactila and Caluromys derbianus), of which two (T. bairdii and M. trydactila) are locally extinct. The other species in IUCN are either of low risk (i. e. Chironectes minimus ) or data deficient (Lontra longicaudis). Additionally, 24 species (39%) are included in CITES.

Aunque Costa Rica ha sido biológicamente bien estudiada, pocas áreas tiene inventarios de mamíferos completos y actualizados,lo que es para llevar a cabo estudios ecológicos y de conservación. La región de San Vito es considerada entre las mas importantes para la investigación científica en el país, debido a la presencia del Jardín Botánico Wilson y la Estación Biológica Las Cruces. Sin embargo, el conocimiento de la mastofauna es incompleto. Por lo tanto se evaluó intensamente los mamíferos de San Vito, y se compiló una lista de especies, con una evaluación de su composición, abundancia relativa, distribución en los habitats, y su estado de conservación. Se registraron 105 especies, que representaron a 85 géneros, 29 familias y 10 órdenes. Los mamíferos no voladores representaron 62 especies, 59 géneros, 23 familias y 9 órdenes. Los murciélagos pertenecieron a 6 familias, 26 géneros y 43 especies. La extensa deforestación y cacería son factores que han causado la extinción local de 7especies, pero la región todavía mantiene un número relativamente alto de su diversidad original, incluyendo a especie raras. Pocas especies fueron comunes o abundantes. La riqueza de especies fue alta en el bosque y los fragmentos de bosque, y más baja en las plantaciones de café, pastizales inducidos y vegetación secundaria. Alrededor del 21% (13) de las espcies estan incluidad en el libro rojo de la UICN. Tres especies (Saimiri oerstedii, Tapirus bairdii y Sylvilagus dicei ) son consideradas en peligro y dos (Myrmecophaga trydactila y Caluromys derbianus ) como amenazadas:de estas, dos especies (T. bairdii and M. trydactila ) se encuentran localmente extintas. Las otras especies son consideradas de bajo riesgo (i. e. Chironectes minimus) o con poca información (i. e. Lontra longicaudis ). Adicionalmente, 24 especies (39%) están incluidas en CITES.

[Diversity, natural history and conservation of mammals from San Vito de Coto Brus, Costa Rica]. / Diversidad, historia natural y conservación de los mamiferos de San Vito de Coto Brus, Costa Rica.

Although Costa Rica has been biologically well studied, few areas have complete mammal inventories, which are essential for ecological studies and conservation. The San Vito region is considered among the most important for scientific research in the country because of the presence of the Wilson Botanical Garden and Las Cruces. However, the knowledge of its mammalian fauna is incomplete. We extensively studied the mammals of San Vito, compiled a checklist, and evaluated its composition, relative abundance, habitat distribution, and conservation status. We recorded 105 species, representing 85 genera, 29 families, and 10 orders. Non-volant mammals represented 62 species, 59 genera, 23 families, and 9 orders. Bats belonged to 6 families, 26 genera and 43 species. The extensive deforestation and hunting have caused the extinction of seven species, but the region still supports, surprisingly, a relatively high number of species, most of which are rare. Few species are common and abundant. Species richness was higher in forest, and forest fragments; fewer species were found in coffee plantations, induced grasslands, and secondary vegetation. Around 21% (13 species) are included in the IUCN red book. Three species are considered endangered (Saimiri oerstedii, Tapirus bairdii, and Sylvilagus dicei), and two threatened (Myrmecophaga trydactila and Caluromys derbianus), of which two (T. bairdii and M. trydactila) are locally extinct. The other species in IUCN are either of low risk (i.e. Chironectes minimus) or data deficient (Lontra longicaudis). Additionally, 24 species (39%) are included in CITES.