Factors shaping bat occurrence in urban green areas
Year: 2013
Type: dissertation
Abstract: Urbanisation is one of mankind’s longer-lasting activities. Bat species most sensitive to human activities have suffered population declines due to urbanisation and the resulting loss of habitats. The presence of urban green areas in a city can promote the presence of bats and increase their activity in general. Little is known about the characteristics that an urban green area should have to promote the presence of bat species. This study was conducted in the municipality of Cascais and addresses three questions: What features of urban green areas promote bat activity? Which urban green areas in Cascais have best conditions for bat occurrence? Which urban green areas should be improved? During 67 nights, between September 2011 and October 2012, 354 points in 15 urban green areas were sampled with bat detectors. A total of 39 variables were used to describe the urban green areas, and their surroundings. The data were statistically analysed using Generalized Linear Mixed Models. The most relevant variables were canopy perimeter, proportion of canopy area in green area, and area covered by low shrubs. Higher bat activity occurs where canopy perimeter is greater, when the relative amount of canopy in a green area is high and where shrub vegetation occurs. Bat activity tends to be null in places where the distance to forest edge is greater than 50m. Four urban green areas stand out by having a high number of predicted bat passes, while in two urban green areas predictions indicate very low levels of bat activity. Results suggest that in order to promote bat activity, urban green areas should be forested, have clearings, extensive edge perimeters and low shrubby vegetation. The majority of urban green areas in the eastern part of the municipality need improvement in order to promote bat presence.
Author: Gonçalo Duarte
Language: English
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W2279299078