Search

Studies quantifying habitat structure generally use several instruments. This paper aims to propose a new and efficient device to characterize microhabitat structure of small mammals. Seven measurements were taken: plant cover, litter cover, rock cover, canopy cover, and vegetative obstruction at three heights. The device is a 0.25 m² square wooden frame (0.50 m x 0.50 m) divided in to 100 open squares by wire mesh. Average time spent to measure each trapping station was six minutes. This new device is efficient, i.e., quick, practical, simple, and reliable. It can be used in any kind of forest. We propose this method as a standard method to describe habitat structure.

The Pampa biome within Brazil is one of South America's most endangered biomes, due to conversion to croplands and use for cattle farming, with very limited coverage by protected areas. We investigated the impacts of (i) human population density, (ii) grassland and (iii) forest cover, (iv) protected areas and (v) mean size of farms on the occurrence patterns of 18 medium‐sized mammal species. We gathered information on the occurrence of these species between 2001 and 2010 from the literature and using unpublished field data from local experts. We obtained 1066 records, varying between 13 and 101 per species. Grassland cover had consistently positive effects on species richness (considering the 18 analyzed species), endangered species (considering 10 species that are endangered or data deficient) and occurrence of five individual species (considering each species separately). Human population density, forest cover and mean size of farms had diverse effects on individual species; however, both forest cover and human population density had positive effects on species richness and endangered species occurrence. For human population density this may result from areas suitable for people being similar to those suitable for many native species. The protected area network of the Pampa biome appeared ineffective at protecting the focal species, with predominantly negative effects on mammal occurrence. This inefficiency is probably related to its minor coverage; only 2.9% of the biome area is under any level of protection and only 0.4% under strict protection. To guarantee the conservation of mammal species in this threatened biome, it is important to protect the last remnants of native vegetation, mainly grasslands, avoiding their conversion into croplands. [ABSTRACT FROM AUTHOR]

We compared the trappability of marked and unmarked individuals in species of marsupials and rodents of three tropical assemblages of small mammals in Brazil. Two studies used trapping grids, one in cerrado and the other in an Atlantic forest reserve, whereas the study in a rural area used transects. In the two studies using trapping grids, marked animals were frequently more trappable than unmarked ones, but in some species this difference was not significant. In the rural area, marked and unmarked animals did not differ significantly. The number of recaptures per resident animal was higher in the two studies using trapping grids than in the rural area where transects were used. Differences in trappability between the three studies might have been caused by differences not only in trapping design (grids vs. transects), but also in the type of trap used, bait, and habitat. Although differential trappability tends to be considered the rule in small mammals, these results suggest that trappability of marked and unmarked animals may be specific for the particular combination of sampling design, field methods, and habitat under study.

The effects of stopcocks on percutaneous fluid drainage were tested in a laboratory model by using a standard stopcock (6-French inner diameter) and a prototype stopcock (9-French inner diameter) connected to 8-, 10-, 12-, 14-, and 16-French catheters. Catheters were immersed in water alone or in viscous fluid with particulate matter, and the system was connected to low wall suction or gravity drainage. The average volume of fluid aspirated in a given period with and without a stopcock was compared for each catheter. The standard stopcock decreased drainage efficiency for these catheters by 13-42%. This decreased drainage efficiency was worse with the larger catheters. Particulate fluid blocked the stopcock connection for all catheters. With the prototype stopcock, drainage of water alone was reduced by 0-9% for the catheters of different sizes. Particulate fluid did not obstruct the prototype stopcock with any size catheter. With gravity drainage, the volume of water aspirated was reduced by 12-42% with the standard stopcock and by 3-6% with the prototype stopcock. These data suggest that stopcock connections greatly influence the efficiency of the percutaneous drainage systems. Stopcocks with larger inner diameters may improve drainage over that achievable with the stopcocks that are currently available.