Search results for "Specie"
showing 10 items of 4389 documents
Camouflage in arid environments: the case of Sahara-Sahel desert rodents
2020
Deserts and semi-deserts, such as the Sahara-Sahel region in North Africa, are exposed environments with restricted vegetation coverage. Due to limited physical surface structures, these open areas provide a promising ecosystem to understand selection for crypsis. Here, we review knowledge on camouflage adaptation in the Sahara-Sahel rodent community, which represents one of the best documented cases of phenotype-environment convergence comprising a marked taxonomic diversity. Through their evolutionary history, several rodent species from the Sahara-Sahel have repeatedly evolved an accurate background matching against visually-guided predators. Top-down selection by predators is therefore …
Impacts of anthropogenic factors on fish community structure in Lebialem-Mone Forest Landscape of Cameroon
2010
Two sites of the Cross River within the Lebialem-Mone forest landscape of Cameroon were chosen, one of the sites faced with human activities (test site) and the other with no human pressure (control site). The lengths and weights of fish obtained from both sites were analyzed in SPSS. Fish communities living within these 2 sites were compared after collecting fish from them using gill nets within 2 months of sampling (September-October 2009). Questionnaires were distributed to the fishers to respond to questions related to their fishing practices. Each fish from a sample of 240 fishes obtained from both sites was identified with its length and weight recorded. Fishing pressure constitutes t…
The toughest animals of the Earth versus global warming: Effects of long-term experimental warming on tardigrade community structure of a temperate d…
2021
Abstract Understanding how different taxa respond to global warming is essential for predicting future changes and elaborating strategies to buffer them. Tardigrades are well known for their ability to survive environmental stressors, such as drying and freezing, by undergoing cryptobiosis and rapidly recovering their metabolic function after stressors cease. Determining the extent to which animals that undergo cryptobiosis are affected by environmental warming will help to understand the real magnitude climate change will have on these organisms. Here, we report on the responses of tardigrades within a five‐year‐long, field‐based artificial warming experiment, which consisted of 12 open‐to…
Antipredatory function of head shape for vipers and their mimics.
2011
Most research into the adaptive significance of warning signals has focused on the colouration and patterns of prey animals. However, behaviour, odour and body shape can also have signal functions and thereby reduce predators' willingness to attack defended prey. European vipers all have a distinctive triangular head shape; and they are all venomous. Several non-venomous snakes, including the subfamily Natricinae, commonly flatten their heads (also known as head triangulation) when disturbed. The adaptive significance of this potential behavioural mimicry has never been investigated. We experimentally tested if the triangular head shape typical of vipers offers protection against predation.…
Polypore communities in broadleaved boreal forests
2012
The cover and extent of boreal broadleaved forests have been decreasing due to modern forest management practices and fire suppression. As decomposers of woody material, polypores are ecologically important ecosystem engineers. The ecology and conservation biology of polypores have been studied intensively in boreal coniferous forests. However, only a few studies have focused on the species living on broadleaved trees. To increase knowledge on this species group we conducted polypore surveys in 27 broadleaved forests and 303 forest compartments (539 ha) on the southern boreal zone in Finland and measured dead wood and forest characteristics. We detected altogether 98 polypore species, of wh…
Species richness of polypores can be increased by supplementing dead wood resource into a boreal forest landscape
2019
1. To prevent local species extinction and to counteract population declines, we must ensure species have access to resources they require for life. This can be done through ecological restoration where previously depleted resources are reintroduced. If the restoration is conducted as a one-off action in a large area, it resembles a natural resource pulse, which should lead to increased abundance of individuals, accompanied possibly by increased species richness. Species–energy relationship and underlying theory enable predictions about how different features of resource pulses affect species richness. 2. We conducted a large-scale, controlled, randomized and replicated field experiment to …
Regional variations in occupancy frequency distributions patterns between odonate assemblages in Fennoscandia
2018
Odonate (damselfly and dragonfly) species richness and species occupancy frequency distributions (SOFD) were analysed in relation to geographical location in standing waters (lakes and ponds) in Fennoscandia, from southern Sweden to central Finland. In total, 46 dragonfly and damselfly species were recorded from 292 waterbodies. Species richness decreased to the north and increased with waterbody area in central Finland, but not in southern Finland or in Sweden. Species occupancy ranged from 1 up to 209 lakes and ponds. Over 50% of the species occurred in less than 10% of the waterbodies, although this proportion decreased to the north. In the southern lakes and ponds, none of the species o…
Ground-dwelling true bugs (Heteroptera) in afforested fields
2017
Former agricultural lands may host peculiar biota, because agriculture activities have changed the physical, chemical and biological features of the soil; however, biodiversity in afforested fields is poorly known. The aim of this study was to investigate the diversity of ground-dwelling true bugs (Heteroptera) in early successional afforested fields in central Finland. We used a large-scale field experiment, in which agricultural land had been afforested 25 years ago by planting monocultures of birch, pine and spruce trees. Pitfall traps caught a total of 224 heteropteran individuals representing 20 species. The community was numerically dominated by Lygaeidae, Drymus brunneus being the mo…
Dead wood and fungi : detection, diversity and conservation in boreal forests
2018
Dead wood and associated fungal communities are a crucial part of boreal forest ecosystems, and severely affected and threatened by human actions like commercial timber harvesting. Despite their importance for forest functioning, most wood-inhabiting fungal species, especially those producing small fruit bodies, are still ecologically and taxonomically poorly known. In addition, studies on dead wood profiles have neglected fine woody debris. This thesis includes detailed investigations of fruiting phenology of different morphological groups and complete dead wood profile of one semi-natural boreal forest. In addition, the diversity patterns of wood-inhabiting fungal communities according fo…
UAS BASED TREE SPECIES IDENTIFICATION USING THE NOVEL FPI BASED HYPERSPECTRAL CAMERAS IN VISIBLE, NIR AND SWIR SPECTRAL RANGES
2016
Abstract. Unmanned airborne systems (UAS) based remote sensing offers flexible tool for environmental monitoring. Novel lightweight Fabry-Perot interferometer (FPI) based, frame format, hyperspectral imaging in the spectral range from 400 to 1600 nm was used for identifying different species of trees in a forest area. To the best of the authors’ knowledge, this was the first research where stereoscopic, hyperspectral VIS, NIR, SWIR data is collected for tree species identification using UAS. The first results of the analysis based on fusion of two FPI-based hyperspectral imagers and RGB camera showed that the novel FPI hyperspectral technology provided accurate geometric, radiometric and sp…