Effects of Gender, Sterilization, and Environment on the Spatial Distribution of Free-Roaming Dogs: An Intervention Study in an Urban Setting.

Information concerning the factors affecting the circulation and distribution of free-roaming dogs is crucial in developing control actions and limiting the spread of zoonoses. The present study analyzes the influence of gender, sterilization, and environment on the spatial distribution of free-roaming dogs in urban settings. Animals were captured/recaptured in seven consecutive morning sampling efforts conducted at 2-monthly intervals in control and intervention areas in a medium-size town in southeastern Brazil. Capture locations were georeferenced and captured animals were microchipped before being released at their original capture sites. Dogs captured in the intervention area were subjected additionally to surgical sterilization prior to release. Home range (HR) areas were calculated by applying the minimum convex polygon method to dogs that had been captured at least three times. Land coverage zones were determined from satellite images and overlaid on maps of the study areas along with the locations of 22 commercial food outlets. HR areas showed a global mean of 448 m2 and a median of 28 m2, values that were smaller than those reported previously for dogs in rural regions. The median HR of females (64.m2) was higher than that of males (15 m2), while median HRs of animals in the control and intervention areas were similar (27 and 28.5 m2, respectively). Variability of HR was high, although animals with small HRs predominated. Free-roaming dogs grouped primarily in urbanized and transitional regions, and their spatial distribution was positively correlated with locations of commercial food outlets. While sterilization did not influence HR size, the search for food was a key factor in determining mobility and spatial aggregation of free-roaming dogs. Our findings are pertinent in understanding the ecology of free-roaming dogs in urban environments and will be applicable to strategies aimed at promoting animal welfare and preventing the dissemination of zoonoses

Análise de invasão biológica e uso de diferentes metodos de controle de Leucaena leucocephala (Lam.) de Wit

Biological invasions have received increasing attention from researchers worldwide and the need for prevention measures has become increasingly evident. Leucaena (Leucaena leucocephala (Lam.) de Wit) is a shrub species on the list of the 100 most aggressive invasive species on the planet. This work aimed to study the biological invasion and control of leucaena in the municipality of Arcos/MG in Brazil. For the evaluation of land occupation by Leucaena from 2005 to 2017, images from the Landsat 7 and 8 satellites were used. For each year evaluated, thematic maps of land occupation of the area of expansion of the exotic species were generated to quantify the total area invaded. For better visualization of the occupied areas and the different classes of vegetation in the Landsat images, maps were generated using the NDVI (Normalized Difference Vegetation Index). The average annual expansion of leucaena in the area was 0.112 ha/year. The control of the species was evaluated using an experimental design with eight treatments and three replications in randomized blocks, with the following treatments: picloram+2,4D (288 +1,080 g ha-1), triclopyr-butotyl (5 L p.c.ha-1), glyphosate (2.40 kg i.a.ha-1), isolated and the same applied later on the stump, after shallow cutting. The best control was achieved by realizing shallow cutting and applying picloram + 2,4D on the stumps, reaching an average of 80% control of the species in 360 days after treatment (DAT).Las invasiones biológicas han recibido una atención cada vez mayor por parte de investigadores de todo el mundo y la necesidad de medidas de prevención se ha vuelto cada vez más evidente. La leucaena (Leucaena leucocephala (Lam.) de Wit) es una especie de arbusto arbóreo que se encuentra en la lista de las 100 especies invasoras más agresivas del planeta. El objetivo de este trabajo fue estudiar la invasión y control biológico de Leucena en el municipio de Arcos/MG en Brasil. Para realizar la evaluación de la ocupación del suelo por parte de Leucena del 2005 al 2017 se utilizaron imágenes de los satélites Landsat 7 y 8. Con el fin de cuantificar el área total invadida, para una mejor visualización de las áreas ocupadas y las diferentes clases de vegetación en las imágenes Landsat, los mapas se generaron utilizando el NDVI (Normalized Difference Vegetation Index). La expansión anual promedio de leucaena en el área fue de 0.112 ha/año. El control de la especie se evaluó mediante un diseño experimental con ocho tratamientos y tres repeticiones en bloques al azar, con los siguientes tratamientos: picloran+2,4D (288 +1,080 g ha-1), triclopir-butil (5 L p.c.ha- 1), glifosato (2,40 kg a.i.ha-1), aislado y aplicado posteriormente al tocón, después de la tala rasa. El mejor control se logró mediante el desbroce y la aplicación de picloram + 2.4D en los tocones, alcanzándose un promedio del 80% de control de la especie a los 360 días después del tratamiento (DDT).Invasões biológicas têm recebido cada vez mais atenção de pesquisadores em todo o mundo e têm se tornado cada vez mais evidente a necessidade de medidas de prevenção. A leucena (Leucaena leucocephala (Lam.) de Wit) é uma espécie arbustivo arbórea que se encontra na lista das 100 espécies invasoras mais agressivas do planeta. O objetivo deste trabalho foi estudar a invasão biológica e controle da leucena no município de Arcos/MG no Brasil. Para a realização da avaliação da ocupação do solo ocorridas pela Leucena dos anos de 2005 a 2017, foram utilizadas imagens dos satélites Landsat 7 e 8. Para cada ano avaliado foram gerados mapas temáticos de ocupação do solo da área de expansão da espécie exótica, a fim de quantificar a área total invadida, para a melhor visualização das áreas ocupadas e das diferentes classes de vegetação nas imagens Landsat, foram gerados mapas com o uso do NDVI (Normalized Difference Vegetation Index). A média de expansão anual da leucena na área foi de 0,112 ha/ano. O controle da espécie foi avaliado utilizando delineamento experimental com oito tratamentos e três repetições em blocos casualizados, sendo os seguintes tratamentos: picloran+2,4D (288 +1.080 g ha-1), triclopir-butotílico (5 L p.c.ha-1), glifosato (2,40 kg i.a.ha-1), isolados e os mesmos aplicado posteriormente no toco, após corte raso. O melhor controle se deu através da realização de corte raso e aplicação de picloram + 2,4D sobre os tocos, atingindo média de 80% de controle da espécie em 360 dias após o tratamento (DAT)

Effects of habitat suitability for vectors, environmental factors and host characteristics on the spatial distribution of the diversity and prevalence of haemosporidians in waterbirds from three Brazilian wetlands

Abstract Background Wetlands are ecosystems in which vectors of avian haemosporidians live and reproduce and where waterbirds join to breed in colonies. Brazil has wetlands at different latitudes, which enables testing the influence of the ecological factors on the prevalence and diversity of haemosporidians. We identified avian haemosporidians in waterbird species in three wetlands and investigated the effects of vector habitat suitability, landscape and host characteristics on the diversity and prevalence of these parasites. Methods We created a map with the probability of occurrence of avian haemosporidian vectors using maximum-entropy modelling based on references addressing species known to be vectors of haemosporidians in birds in Brazil. We determined the prevalence and diversity index of haemosporidians in the great egret (Ardea alba) (n = 129) and roseate spoonbill (Platalea ajaja) (n = 180) and compared the findings to data for the wood stork (Mycteria americana) (n = 199). Results We report the first record of Plasmodium in the family Threskiornithidae: four lineages in the roseate spoonbill, which also presented one lineage of Haemoproteus. In the family Ardeidae, we found three Plasmodium lineages in the great egret. The similar habitat suitability for vectors found in three wetlands explains the pattern of haemosporidian diversity determined for great egret and wood stork populations. Comparisons of haemosporidian diversity within each waterbird species and between regions showed a higher level in the central-western roseate spoonbill population than in the northern population (P = 0.021). Removing the host effect, we discussed the results obtained in terms of characteristics of the Pantanal region. Comparisons of Plasmodium spp. prevalence among waterbird species within the same wetland showed higher level in roseate spoonbill (74%) than those found in the great egret (21%) and wood stork (11%). Excluding the environmental effect, we interpreted result focusing host characteristics that favour infection: time required for nestlings to be covered by feathers and migratory behaviour. Conclusions The map of habitat suitability showed that wetlands located in a 30° latitudinal range offer similar conditions for avian vectors species and diversity of haemosporidians. The lineages described in waterbirds were previously identified in birds of prey as Plasmodium paranucleophilum