Search results for "ecological"
showing 10 items of 1263 documents
Fragmentation-related patterns of genetic differentiation in pedunculate oak (<i>Quercus robur</i>) at two hierarchical scales
2016
Populations at speciesâ range margins are expected to show lower genetic diversity than populations at the core of the range. Yet, long-lived, widespread tree species are expected to be resistant to genetic impoverishment, thus showing comparatively high genetic diversity within populations and low differentiation among populations. Here, we study the distribution of genetic variation in the pedunculate oak ( L.) at its range margin in Finland at two hierarchical scales using 15 microsatellite loci. At a regional scale, we compared variation within versus among three oak populations. At a landscape scale, we examined genetic structuring within one of these populations, growing on an islan…
Inconsistent relationships among protection, benthic assemblage, habitat complexity and fish biomass in Mediterranean temperate rocky reefs
2021
International audience; Marine Protected Areas (MPAs) have been proved to effectively protect and restore fish assemblages. There is mixed evidence regarding the effects of MPAs on benthic assemblages, habitat complexity, and how protection might mediate the effects of habitat features (including biotic and abiotic components) on fish assemblages, with very little information concerning temperate areas. Here, our aim is to assess how protection 1) influences benthic assemblages and habitat complexity, and 2) mediates the effects of habitat complexity on fishes.Using non-destructive methods (photosampling for shallow rocky benthic assemblages, and underwater visual census using strip transec…
Machine learning predictions of trophic status indicators and plankton dynamic in coastal lagoons
2018
Abstract Multivariate trophic indices provide an efficient way to assess and classify the eutrophication level and ecological status of a given water body, but their computation requires the availability of experimental information on many parameters, including biological data, that might not always be available. Here we show that machine learning techniques – once trained against a full data set – can be used to infer plankton biomass information from chemical and physical parameter only, so that trophic index can then be computed without using additional biological data. More specifically, we reconstruct plankton information from chemical and physical data, and this information together w…
Tracking management-related water quality alterations by phytoplankton assemblages in a tropical reservoir
2015
Water quality improvement and suppression of cyanobacterial blooms were planned in a eutrophic reservoir in southern China through ecological engineering measures from 2006 to 2011. This consisted in (i) a hydraulic resetting of inflows and outflows to increase the distance between inlet and outlet and the water residence time in the reservoir, and in (ii) the installation of floating frames hosting wetland vegetation to promote an alteration in phytoplankton composition. The environmental changes were therefore followed through the analysis of biotic responses in phytoplankton assemblages. Ecological engineering was effective in reducing phytoplankton total biomass, in re-establishing more…
Ecology, Phylogeny, and Potential Nutritional and Medicinal Value of a Rare White “Maitake” Collected in a Mediterranean Forest
2020
Albino Grifola frondosa (Dicks.) Gray &ldquo
Coupling agent-based with equation-based models to study spatially explicit megapopulation dynamics
2018
International audience; The incorporation of the spatial heterogeneity of real landscapes into population dynamics remains extremely difficult. We propose combining equation-based modelling (EBM) and agent-based modelling (ABM) to overcome the difficulties classically encountered. ABM facilitates the description of entities that act according to specific rules evolving on various scales. However, a large number of entities may lead to computational difficulties (e.g., for populations of small mammals, such as voles, that can exceed millions of individuals). Here, EBM handles age-structured population growth, and ABM represents the spreading of voles on large scales. Simulations applied to t…
Introduction of Mysis relicta (Mysida) reduces niche segregation between deep-water Arctic charr morphs
2019
This is a post-peer-review, pre-copyedit version of an article published in Hydrobiologia. The final authenticated version is available online at https://doi.org/10.1007/s10750-019-3953-4. Niche diversification of polymorphic Arctic charr can be altered by multiple anthropogenic stressors. The opossum-shrimp (Mysis relicta) was introduced to compensate for reduced food resources for fish following hydropower operations in Lake Limingen, central Norway. Based on habitat use, stomach contents, stable isotopes (δ13C, δ15N) and trophically transmitted parasites, the zooplanktivorous upper water-column dwelling ‘normal’ morph was clearly trophically separated from two sympatric deep-water morphs…
Spatial variability of soil roughness in persimmon plantations: A new combined ISUM (improved stock unearthing method) approach
2019
Made available in DSpace on 2019-10-06T16:49:52Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-11-01 Universidade Estadual Paulista Soil roughness (SR) is an ecological indicator that describes the distribution of soil surface accumulations and ponds in a terrain, which allows understanding the connectivity of the flows as they act as sinks and sources of water and sediments. There is a set of methods that allows investigating the SR, and we test the use of the improved stock unearthing method (ISUM) as an easy-to-apply and low-cost approach. The ISUM has been initially tested in vineyards using the graft union and measures in the inter-row areas to assess the current soil surface l…
The Effects of Peatland Restoration on Water-Table Depth, Elemental Concentrations, and Vegetation: 10 Years of Changes
2010
We studied the effects of restoration on water-table depth (WTD), element concentrations of peat and vegetation composition of peatlands drained for forestry in southern Finland. The restoration aimed to return the trajectory of vegetation succession toward that of undisturbed systems through the blockage of ditches and the removal of trees. Permanent plots established on a bog and a fen were sampled 1 year before, and 1, 2, 3, and 10 years after the restoration. The restoration resulted in a long-term rise of the water-table in both peatlands. Ten years after restoration, the mineral element concentrations (Ca, K, Mg, Mn, and P) of peat corresponded to those reported from comparable pristi…
Precision, Applicability, and Economic Implications: A Comparison of Alternative Biodiversity Offset Indexes
2021
AbstractThe rates of ecosystem degradation and biodiversity loss are alarming and current conservation efforts are not sufficient to stop them. The need for new tools is urgent. One approach is biodiversity offsetting: a developer causing habitat degradation provides an improvement in biodiversity so that the lost ecological value is compensated for. Accurate and ecologically meaningful measurement of losses and estimation of gains are essential in reaching the no net loss goal or any other desired outcome of biodiversity offsetting. The chosen calculation method strongly influences biodiversity outcomes. We compare a multiplicative method, which is based on a habitat condition index develo…