Bongi, Paolo (2009) Environmental and human factors affecting spatial behaviour and detectability of roe deer (capreolus capreolus): influence on population estimate. Doctoral Thesis.
This work confirmed one of the most crucial issues of wildlife management, i.e., how it’s difficult to estimate roe deer population density. I checked for different accuracy of roe deer census methods. Census methods were considered according to environmental characteristic, i.e., one of the major factors affecting bias in roe deer density estimation. A strong underestimation was given in the use of the line transect, block count, and spotlight count techniques. Depending on environmental characteristics, the two best methods are the observation from vantage points and the drive census, while the pellet group count is strongly suggested as a control method. Some human (hunting, logging activities) and ecological (prey-predator relationship, behavioural ecology of monitored species) factors should be take into consideration before proceed to plan management activities such censuses. When hunting practices were allowed, roe deer shifted their center of activity inside protected areas. Managers have to contend with roe deer movement as a response to hunting activities, and related deer concentrations inside protected areas during the hunting season. Logging activities are able to affect deer movement. In presence of clear-cutting areas, roe deer were shown to increase the use of this areas during and immediately after forest work. I also considered ecological factors that may affect roe deer spatial behaviour. In a wolf area, females with fawn were shown to use habitat more dense than female without fawn, as a consequence of antipredator strategies adopted by mothers in order to increase the survival of offspring. The detectability of roe deer mother with their fawns is lower during the first part of weaning and, consequently, estimation of the population size and population increase may be underestimated during crucial periods of the annual biological cycle of the monitored species.
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