Search results for "succe"
showing 10 items of 990 documents
Evaluation of a technical revegetation action performed on foredunes at Devesa de la Albufera, Valencia, Spain
2010
We have evaluated the level of restoration achieved by a technical revegetation action carried out on reconstructed foredunes at the Devesa de la Albufera and compared this level with that achieved by spontaneous succession. Foredunes 1, 3, 6 and 20 y old since revegetated (1, 3, 6 and 20 y, respectively) were considered as spatially separated stages representing a successional trend in the development of the restored plant community. Lower and similar levels of diversity (richness and H´ and Pielou´s indexes) and coverage, respectively, were found on dunes corresponding to the oldest stage of technical revegetation compared with that of the reference site. Diversity and coverage parameters…
Evaluation of different similarity indices as measures of succession in arthropod communities of the forest floor after clear-cutting.
1979
Communities of spiders (Araneae) and beetles (Coleoptera) living in the soil and litter of clear-cut areas were compared with those of intact forest stands. Sixteen different indices of similarity were tested on three sets of material: spiders and beetles examined during one year in three clear-cut areas felled 3, 6 and 9 years earlier, and spiders in one clear-cut area examined during 7 successive years after felling. Other sources of evidence showed that succession in the spider community was divergent for at least 7 years after felling. The indices that seemed to express the changes best were: (1) Kendall's rank correlation test, (2) the Bray-Curtis measure, (3) Renkonen's percentage sim…
Effects of forest regeneration on the structure of bird communities in northern Finland
1985
Breeding bird communities in five stages of secondary forest succession were studied in northeastern Finland in 1980–82. Three groups of communities were distinguished: open land, brush phase and forest communities, dominated by Motacilla alba and Oenanthe oenanthe, Phylloscopus trochilus and Anthus trivialis, Phylloscopus trochilus and Fringilla montifringilla, respectively. Pair density, number of species, biomass of adult birds and species diversity increased in the course of succession, none of these, however, monotonously. Average bird weight showed a decreasing trend although the variation was considerable. The degree of specialization in communities (measured by ratios derived from n…
Reforming the Teaching and Learning of Foundational Mathematics Courses: An Investigation into the Status Quo of Teaching, Feedback Delivery, and Ass…
2022
Several universities are witnessing an increase in students’ enrolment in mathematics-intensive programmes over the last decades. This increase has come with the price of high failure rates in foundational mathematics courses, which poses challenges to mathematics teaching and learning in higher education. It is therefore inevitable, for some universities, to transform the teaching and learning of mathematics to more student-centred approaches that engage the students mathematically and enhance their success rates. We approach this transformative effort by investigating students’ perception of teaching, feedback, and assessment as a first step in reforming the teaching of a firs…
Sex-Biased Inbreeding Effects on Reproductive Success and Home Range Size of the Critically Endangered Black Rhinoceros
2013
A central premise of conservation biology is that small populations suffer reduced viability through loss of genetic diversity and inbreeding. However, there is little evidence that variation in inbreeding impacts individual reproductive success within remnant populations of threatened taxa, largely due to problems associated with obtaining comprehensive pedigree information to estimate inbreeding. In the critically en- dangered black rhinoceros, a species that experienced severe demographic reductions, we used model selection to identify factors associated with variation in reproductive success (number of offspring). Factors examined as predictors of reproductive success were age, home ran…
Multiple paternity and mating group size in the European earwig,Forficula auricularia
2014
The patterns of multiple paternity among the progeny of females are key properties of genetic mating systems. Female multiple mating should evolve due to direct or indirect benefits, but it may also partly be driven by the encounter rate with different potential mates. 2. In this study this hypothesis was experimentally tested in the European earwig (Forficula auricularia L.) by establishing experimental mating groups that differed in the number of males and females (i.e. density). The number of sires and mean sibling relatedness in each clutch were estimated using microsatellite-based paternity analysis. 3. As predicted, the mean number of sires per clutch was significantly increased, and …
Inbreeding depression in an insect with maternal care: influences of family interactions, life stage and offspring sex.
2013
Although inbreeding is commonly known to depress individual fitness, the severity of inbreeding depression varies considerably across species. Among the factors contributing to this variation, family interactions, life stage and sex of offspring have been proposed, but their joint influence on inbreeding depression remains poorly understood. Here, we demonstrate that these three factors jointly shape inbreeding depression in the European earwig, Forficula auricularia. Using a series of cross-breeding, split-clutch and brood size manipulation experiments conducted over two generations, we first showed that sib mating (leading to inbred offspring) did not influence the reproductive success of…
Why do female bank voles, Clethrionomys glareolus, mate multiply?
2007
Females of many species actively engage in multiple mating, with either a single male or several males, but the adaptive function of this behaviour is often unclear. We conducted a laboratory experiment on a small mammal species, the bank vole, testing the possible benefits of multiple mating on a female's short-term reproductive success (pregnancy rate, litter size and early postnatal survival). Such benefits may affect a female's fitness either directly or indirectly (genetic benefit). We assigned females to three treatments: a single mating treatment in which females mated once with a single male and two multiple mating treatments in which females mated either twice with a single male or…
Seventy-year changes in tree species composition and tree ages in state-owned forests in Latvia
2011
Abstract During the last 100 years, forest management in Latvia has gradually become more and more focused on industrial logging, which can be expected to have affected the tree species composition and age distribution across the landscape. These changes need to be considered in forest management and conservation of biological diversity. The aim of the study was to use forest records to reconstruct the tree species composition and age distribution in the North Vidzeme Biosphere Reserve in northern Latvia for the period, 1929–1941. These data were compared to a data-set from 2008, to determine the changes that transpired during a period of intensification of forest management. The silvicultu…
Long-Term Observations of Soil Mesofauna
2010
General problems connected with planning, sampling, and data processing of long-term research of soil mesofauna are discussed, based on two case studies: (i) the Bremen study of predatory mites (Gamasina) covering 20 years of secondary succession on a ruderal site in northern Germany and (ii) the Mazsalaca study of the effects of climate warming on Collembola of coniferous stands in the North Vidzeme Biosphere Reserve, Latvia, covering 11 years. The findings from both sites are embedded in an array of environmental data. The results from Bremen document the asynchrony of different biota in successional dynamics. The long-lasting increase of the species numbers of soil predatory mites (Gamas…