Factors affecting southern water vole (Arvicola sapidus) detection and occupancy probabilities in Mediterranean farmland

Failure to detect a species at sites where it is present (i.e. imperfect detection) is known to occur frequently, but this is often disregarded in monitoring programs and metapopulation studies. Here we modelled for the first time the probability of patch occupancy by a threatened small mammal, the southern water vole (Arvicola sapidus, while accounting for the probability of detection given occupancy. Based on replicated presence sign surveys conducted in autumn (November–December 2013) and winter (February–March 2014) in a farmland landscape, we used occupancy detection modelling to test the effects of vegetation, sampling effort, observer experience, and rainfall on detection probability. We then assessed whether occupancy was related to patch size, isolation, vegetation, or presence of water, after correcting for imperfect detection. The mean detection probabilities of water vole signs in autumn (0.71) and winter (0.81) indicated that false absences may be generated in about 20–30% of occupied patches surveyed by a single observer on a single occasion. There was no statistical support for the effects of covariates on detectability. After controlling for imperfect detection, the mean probabilities of occupancy in autumn (0.31) and winter (0.29) were positively related to patch size and presence of water, and negatively so, albeit weakly, to patch isolation. Overall, our study underlined the importance of accounting for imperfect detection in sign surveys of small mammals such as water voles, pointing out the need to use occupancy detection modelling together with replicate surveys for accurately estimating occupancy and the factors affecting it.

An intervention program for children with school failure problems.

School failure is a chronic problem in many developing countries and in some developed as Portugal due to factors like cognitive deficiencies of children, an inadequate family environment, low SES and bad teaching methods or school organization. It is important to develop effective and simple intervention strategies able to cope with the problem at an individual level independently of the cause. The general objective of the following study is to develop behavioral training techniques to help children with problems of school failure. 6 - 12 years old children attending ISCED 1, with academic difficulties because of family problems, social exclusion (living in poverty or belonging to an ethnic minority) or poor schooling were trained. Cognitive-behavioral techniques that have been widely used to train persons with intellectual, sensorial, physical or social deficiencies were applied. Results are evaluated in terms of % of attained objectives, time, and (subjective) teacher satisfaction. Some results of individual children are shown. Training programs seem to be successful independently of the (mostly unknown) cause of failure of the trained subject.