10 research outputs found
Group dynamics, behavior, and current and historical abundance of peccaries in Costa Rica’s Caribbean lowlands
The abundances and habitat preferences of peccaries in Neotropical forests are important to understand because these keystone species influence many aspects of the ecosystem. In the Caribbean lowlands of Costa Rica, we conducted walking surveys for ~2 years to study the behavior and population trends of collared peccaries (Pecari tajacu), and found that peccaries are abundant at La Selva Biological Station and overall, detection rates were relatively constant through time. A stable estimate of detection rates was achieved only after 7–9 months of surveying. We found no habitat preferences between primary and secondary forest, yet there were some differences in group dynamics—group radius was larger and sighting distance was greater in primary forest, whereas the number of singletons was higher in secondary forest. More peccaries were seen closer to the laboratory clearing than at greater distances, for a variety of probable reasons: habituation to humans, lower predation and hunting pressure, and various environmental and habitat factors. Peccary groups had spatially clumped distributions across the landscape and were more active diurnally than nocturnally. Collared peccary densities are relatively high at La Selva compared to other Neotropical sites, with the exception of Barro Colorado Island. We combined our data with a review of the historical literature to assess changes in the populations of peccaries in the Caribbean lowlands. We found that collared peccaries have likely increased in abundance at La Selva, seemingly a few years after the extirpation of white-lipped peccaries (Tayassu pecari), which were abundant in the area 40–50 years ago. An understanding of the group dynamics, behavior, and habitat preference of collared peccaries is essential for management decisions and conservation efforts. Additionally, assessment of population changes should be carefully considered in a historical context, with a particular focus on how the populations of the 2 peccary species have changed, and how these species might differentially affect their environment. Resumen--Entender la abundancia y la preferencia de hábitat de las 2 especies de sainos en bosques neotropicales es importante porque estas especies clave afectan muchos aspectos del ecosistema. En las tierras bajas del Caribe costarricense, llevamos a cabo muestreos a pie durante ~2 años para estudiar el comportamiento y tendencias poblacionales del saino (Pecari tajacu), y encontramos que son abundantes en la Estación Biológica La Selva y las tasas de detección fueron relativamente constantes a través del tiempo. Se obtuvo una tasa estable de detección después de 7–9 meses de muestreos. Las tasas de detección fueron similares en bosque primario y secundario, sin embargo, se encontraron algunas diferencias en la dinámica de grupo (el radio de distribución del grupo era más grande y distancia de observación fue mayor en bosques primarios, mientras que el número de individuos solitarios fue mayor en bosques secundarios). Más sainos fueron vistos alrededor de las zonas abiertas rodeando el laboratorio, debido a varias posibles razones: habituación a la presencia de seres humanos, menos presión por depredación o cacerÃa y otros factores ambientales o de hábitat. Los sainos están distribuidos de forma aglomerados y son más activos de dÃa que de noche. Las densidades de sainos son relativamente altas en comparación con otros sitios neotropicales, con excepción de la Isla de Barro Colorado. El saino probablemente ha aumentado en abundancia en La Selva, aparentemente unos años después de la extirpación del cariblanco (Tayassu pecari), que eran abundantes en el área hace unos 40–50 años. El conocimiento de la dinámica de grupos, comportamiento y preferencias de hábitat del saino es esencial para las decisiones de manejo y los esfuerzos de conservación. Además, la evaluación de los cambios poblacionales debe considerarse cuidadosamente en un contexto histórico, con especial atención a cómo han cambiado las poblaciones del saino y cariblanco, y cómo estas especies afectan su ambiente
Impacts of environmental change on agroecosystems and livelihoods in Annapurna Conservation Area, Nepal
© 2017 Elsevier B.V. To understand local perceptions of the impacts of environmental change in two mountain districts of Nepal — Myagdi and Mustang — between 2010 and 2014, a survey, focus groups, town hall meetings, and extensive consultation with local stakeholders were conducted, supplemented by analyses of soil, rainfall, and temperature data. Mountain people in Nepal shared their perceptions of environmental change in their everyday lives, including agricultural practices and tourism activities. While ordinary individuals welcome the construction of new roads, elites still prefer to maintain trails and the status quo. People are concerned about the introduction of mosquitoes, increases in insect pests and plant pathogens, and other vectors along with roads. Snowfall has decreased and rainfall has been unpredictable. Mean minimum winter temperatures have increased and the mountains are experiencing shorter winters and less snow accumulation, which threaten the livelihoods of people that depend on fresh water. While people with means are replacing their traditional homes with modern homes, that is beyond reach for average Mustangi citizens. Expansion and diversification of agriculture, adoption of sound soil management techniques in Marpha village of Mustang and Shikha village of Myagdi, and growing forest cover in Shikha are some indicators of enhanced community managed practices. The coping strategies and indigenous practices adopted by local people in the region against hardship and environmental changes could serve as examples in similar mountain settings elsewhere
Sagebrush-Obligate Passerine Response to Ecological Site Characteristics
Adoption of ecological sites as monitoring and management units by a variety of land users has prompted discussion of their benefits for wildlife habitat management. Density and occurrence of shrub-steppe passerines are often related to key habitat characteristics such as plant species composition, cover, and structure. Until recently, ecological sites have not been tested as units for monitoring and management of passerines. We conducted a study implementing ecological sites as management units and used passerines as indicators of potential use of these sites. Ecological site characteristics and three sagebrush-obligate passerines were quantified on ecological sites at and near Browns Park National Wildlife Refuge in Colorado. In 2006 and 2007, we surveyed passerines and site characteristics using standard techniques within 101, 100-m radius plots. Density of Brewer’s sparrow (Spizella breweri) and occurrence of Brewer’s sparrow, sage sparrow (Amphispiza belli), and sage thrasher (Oreoscoptes montanu) were estimated for six ecological sites and then related to site characteristics. For example, Brewer’s sparrow densities were greatest (3.0 birds/ha) on a Loamy Fine Sand Ecological Site containing taller vegetation than vegetation for other ecological sites. Scientific literature commonly associates Brewer’s sparrows with sagebrush (Artemisia tridentata) presence, but on ecological sites at Browns Park Brewer’s densities are related more to vegetative structure rather than species composition. Results show there are links between passerine populations and ecological sites; a relationship which provides a meaningful foundation in developing long-term monitoring protocols and enhancing management decisions to favor sagebrush-obligate passerines
\u3ci\u3eShort communication\u3c/i\u3e: A countrywide survey of antimicrobialresistant indicator bacteria in Kosovo’s dairy farms
The World Health Organization recently recognized the Republic of Kosovo as one of the highest consumers per capita of antibiotics for human use among non- European Union Eastern European countries; however, data are limited regarding antimicrobial usage and antimicrobial resistance in the livestock sector for this recently formed country. The objective of this study was to conduct the first nationwide survey of antimicrobial resistance phenotypes in indicator bacteria collected from dairy farms in Kosovo. Composite fecal samples were collected from 52 farms located within all 7 administrative districts of Kosovo in the summer of 2014. Isolation and characterization of the indicator bacteria Escherichia coli (n = 165) and Enterococcus spp. (n = 153) from these samples was achieved by culturing on selective/differential media with and without select antibiotics, followed by MALDI-TOF (matrixassisted laser desorption/ionization time-of-flight) mass spectrometry-based identification and antimicrobial susceptibility testing using the disk diffusion method. When no selective pressure was applied in culture-based isolation, the majority of E. coli and Enterococcus spp. collected were resistant to ≤1 of 16 and ≤2 of 12 antibiotics tested, respectively. In contrast, E. coli and Enterococcus spp. isolated using sub-minimum inhibitory concentrations of cefoxitin, ciprofloxacin, or erythromycin were typically resistant to at least one and often multiple antibiotic types, which primarily consisted of certain β-lactams, quinolones, sulfonamides, phenicols, and tetracyclines for E. coli isolates and macrolides, tetracyclines, and rifamycins for enterococci isolates
Nonvolant mammalian populations in primary and secondary Neotropical rainforests as revealed by transect surveys.
Secondary forests are now prominent features in Neotropical landscapes, yet little is known about their conservation value for nonvolant mammalian communities. We performed a 20-month study using transect walks to survey the nonvolant mammal fauna in primary and secondary forests at La Selva Biological Station in the Caribbean lowlands of northeastern Costa Rica. We found that secondary forests can hold complex mammalian communities and no species exhibited habitat preferences between primary and secondary forests. With few exceptions, behavioral and group dynamic characteristics of mammal species were similar between forest types. Our research allows us to address methodological questions and assess the effectiveness of transect sampling. Monthly detection rates vary widely by species and likely reflect short-term changes in behavior rather than population fluctuations. Air temperature and rainfall are the factors most associated with monthly detection rates for various species. Small-scale areas of higher and lower use are evident for several species. Neither time of morning for surveys nor number of observers per trail affects detection rate. We report current abundances for the most commonly observed species and note generally lower
densities in the Caribbean lowlands than elsewhere in the Neotropics. This research highlights that in less seasonal, evergreen forests climatic factors can still affect mammalian behavior. Overall, we find that secondary forests are of high conservation value and that transect walks are an effective methodology to sample many nonvolant mammal species, and we present recommendations on how to sample properly to conduct rigorous and long-term studies.
Los bosques secundarios son mucho más comunes en el neotrópico, pero poco se sabe sobre su importancia en la conservación de comunidades de mamÃferos no voladores. Durante 20 meses llevamos a cabo un estudio usando lÃneas de transectos para investigar la fauna de mamÃferos no voladores en bosques primarios y secundarios en la Estación Biológica La Selva en las tierras bajas caribeñas al noreste de Costa Rica. Pudimos constatar que los bosques secundarios pueden albergarcomplejas comunidades de mamÃferos y ninguna especie exhibe preferencias de hábitat entre bosque primario y secundario. Con pocas excepciones, las caracterÃsticas dinámicas de grupo y comportamiento de especies de mamÃferos fueron similares entre los dos tipos de bosque. Nuestra
investigación nos permite abordar cuestiones metodológicas y evaluar la eficacia del muestreo con transectos. Las tasas mensuales de detección varÃan de acuerdo a la especie y probablemente reflejan cambios a corto plazo en las fluctuaciones del comportamiento en vez de la población. La temperatura del aire y la precipitación son los factores más asociados con las tasas mensuales de detección de distintas especies. Encontramos que varias especies muestran diferentes incidencias de uso en zonas pequeñas. Ni la hora de la mañana, ni el número de observadores en las encuestas por transecto afectan la tasa de detección. Presentamos la abundancia actual de las especies más comúnmente observadas y notamos en general bajas densidades en las tierras bajas del Caribe
más que en otras partes del neotrópico. Esta investigación resalta que en los bosques menos estacionales, factores climáticos aún pueden afectar el comportamiento de mamÃferos. En general, encontramos que los bosques secundarios son de alto valor para la conservación y que los muestreos en transectos son una metodologÃa eficaz para estudiar muchas especies de mamÃferos no voladores y presentamos recomendaciones sobre cómo llevar a cabo muestreos adecuados para realizar estudios rigurosos a largo plazo
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Songbird Relationships to Shrub-Steppe Ecological Site Characteristics
Rangeland managers are often faced with the complex challenge of managing sites for multiple uses and for the diverse interests of stakeholders. Standardized monitoring methods that can be used and understood by different agencies and stakeholders would aid management for long-term sustainability of rangelands. In the United States, federal land management agencies have recently based their assessments of rangeland health and integrity on state-and-transition models to consider management trajectories. Ecological sites provide a foundation for these efforts but have not been used to address wildlife habitat. Habitat preferences are documented for North American shrub-steppe songbirds but have yet to be related to ecological sites and site characteristics. We characterized ecological sites at Browns Park National Wildlife Refuge, Colorado, using established rangeland monitoring methods to test whether 1) songbird species density and diversity differ among adjacent shrub-steppe ecological sites and 2) quantifiable ecological site characteristics could be identified that account for significant variation in songbird density and diversity. Vegetation structure (represented as basal and canopy gaps, cover, height, and shrub density) differentiated the four ecological sites and was related to songbird density and diversity. Sage sparrows (Amphispiza belli) and vesper sparrows (Pooecetes gramineu) selected habitat based on horizontal characteristics of vegetation structure, such as basal and canopy gap and plant species cover. Brewer’s sparrow (Spizella breweri), lark sparrow (Chondestes grammacus), and songbird diversity were more strongly related to vegetation structure of the plant communities than to plant composition. Our results support use of ecological sites as management units to characterize songbird habitat given that songbird density and diversity were related to site vegetation characteristics. By incorporating basal and canopy gap, height, plant cover, and shrub density monitoring methods into ecological site descriptions, managers would be provided with additional tools to assist in differentiating songbird habitat.The Rangeland Ecology & Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202