masterThesis
Atividade de morcegos insetívoros (mammalia, chiroptera) no pampa brasileiro: uso de hábitat e sazonalidade
Fecha
2012-05-30Registro en:
BARROS, Marília Abero Sá de. Atividade de morcegos insetívoros (mammalia, chiroptera) no pampa brasileiro: uso de hábitat e sazonalidade. 2012. 88 f. Dissertação (Mestrado em Estudos de Comportamento; Psicologia Fisiológica) - Universidade Federal do Rio Grande do Norte, Natal, 2012.
Autor
Barros, Marília Abero Sá de
Resumen
Bats correspond to 20% of the extant mammal species and, with a few exceptions, use
echolocation, a spacial orientation system based on emission and analysis of echoes from
sound waves, generally ultrasounds. Echolocation was discovered in the 1940 s and since the
1970 s ultrasound detectors have been commercially available, allowing the investigation of
several aspects of the natural history and ecology of bats. Passive acoustic monitoring has
been frequently used in habitat use studies, predominantly in North America and Europe, by
comparing the number of bat passes between different habitat types. This dissertation presents
the first evaluation of the spacial and seasonal variation patterns in the activity of
insectivorous bats in the Brazilian biome Pampa, in the state of Rio Grande do Sul. Since bat
activity can vary according to habitat type, time of year and climatic conditions, the following
hypotheses were tested: 1. bat activity varies between different types of habitat; 2. bat activity
varies seasonally; 3. bat activity is influenced by temperature, humidity and wind speed. The
acoustic samples were taken along fixed transects of 1500 meters, which were monitored
monthly from April 2009 to March 2010. Five habitat types were sampled: eucalypts, stream,
riparian forest, wetland and grassland. In each sample, the number of bat passes was obtained
by using an ultrasound detector Pettersson D230. A total of 1183 bat passes were registered.
Greater bat activity levels was observed along large eucalypts (1.93 bat passes/3min) and
along a stream (1.61 bat passes/3 min). A riparian forest (0.94 bat passes/3 min) and a wetland
area (0.61 bat passes/3 min) exhibited statistically equal levels of activity. Bat passes were
fewer in grassland areas (0,16 bat passes/3 min). Bat activity was not correlated with abiotic factors. However, bat activity was significantly low in the colder season, winter, and was
similar in autumn, spring and summer. The observed preference for vegetation borders and
water courses agrees with reports from other countries and is attributed predominantly to the
high prey abundance in these types of environments. Additionally, low activity in the winter
is probably a response to the reduced availability of insects, and to lower temperatures. Our
results indicate which areas of arboreal vegetation and water courses should be priorities for
the conservation of bats and that alterations of these habitat types might negatively influence
bat activity in the region