Search results for "Spatial Ecology"
showing 10 items of 191 documents
Fine-scale population dynamics in a marine fish species inferred from dynamic state-space models
2017
1. Identifying the spatial scale of population structuring is critical for the conservation of natural populations and for drawing accurate ecological inferences. However, population studies often use spatially aggregated data to draw inferences about population trends and drivers, potentially masking ecologically relevant population sub‐structure and dynamics. 2. The goals of this study were to investigate how population dynamics models with and without spatial structure affect inferences on population trends and the identification of intrinsic drivers of population dynamics (e.g. density dependence). 3. Specifically, we developed dynamic, age‐structured, state‐space models to test differe…
Temporal and spatial patterns of trawl fishing activities in the Adriatic Sea (Central Mediterranean Sea, GSA17)
2020
Abstract Trawl fishing activities have occurred for centuries on large spatial scale in the entire Mediterranean Sea, and today they are considered as one of the main and widespread causes of anthropogenic disturbance and habitat alteration in the marine environment. In order to delineate when, where and how marine ecosystems have been perturbed and to implement ecosystem-based management strategies, the identification and investigation of the spatial and temporal distribution of fishing effort and the fleet dynamics play a key role. In this context, Geospatial Technologies such as the Automatic Identification System (AIS) could represent a useful tool. The aim of the present work is to rec…
Blowing in the wind: how many roads can a phytoplanktont walk down? A synthesis on phytoplankton biogeography and spatial processes
2015
The selected theme of the 17th Workshop of the International Association for Phytoplankton Taxonomy and Ecology (IAP), ‘‘Biogeography and Spatial Patterns of Biodiversity of Freshwater Phytoplankton,’’ offered the opportunity to explore one neglected aspect of phytoplankton ecology: the distribution of species in the geographic space. This paper summarizes the outcomes of 20 selected contributions among those presented at the workshop. The articles report the results from studies carried out in five continents (only Oceania is not represented) and on a wide array of aquatic ecosystems (deep and shallow natural lakes, man-made lakes, temporary and permanent ponds, rivers). The topics analyze…
Hydrology Affects Environmental and Spatial Structuring of Microalgal Metacommunities in Tropical Pacific Coast Wetlands
2016
The alternating climate between wet and dry periods has important effects on the hydrology and therefore on niche-based processes of water bodies in tropical areas. Additionally, assemblages of microorganism can show spatial patterns, in the form of a distance decay relationship due to their size or life form. We aimed to test spatial and environmental effects, modulated by a seasonal flooding climatic pattern, on the distribution of microalgae in 30 wetlands of a tropical dry forest region: the Pacific coast of Costa Rica and Nicaragua. Three surveys were conducted corresponding to the beginning, the highest peak, and the end of the hydrological year during the wet season, and species abun…
Spatial heterogeneity of spring phytoplankton in a large tropical reservoir: could mass effect homogenize the heterogeneity by species sorting?
2018
Reservoirs are river–lake hybrid ecosystems characterized by a marked longitudinal zonation and variable flushing rates depending on the use of stored waters. The structure of their phytoplankton is therefore subjected to the interplay between the environmental conditions of the different zones (species sorting) and the strength of the unidirectional flow (mass effect). The spatial distribution of spring phytoplankton was investigated in a tropical reservoir across its different zones. Phytoplankton displayed heterogeneous spatial patterns from the turbulent, nutrient-rich riverine zones to the relatively stable lacustrine zone. The analysis of this spatial heterogeneity revealed the relati…
Effect of landscape structure on common vole (Microtus arvalis) distribution and abundance at several space scales
1996
This paper aims to answer the following question: are the fluctuations of abundance of Common Vole (Microtus arvalis) specific to different types of landscapes? The research was carried out in landscapes where grassland was dominant. The sampling method was based upon a partition in both landscape types and landscape units. Tracking of vole indices was used to evaluate their relative abundance. Six landscape transects were sampled during two successive years. Results show that population variation and diffusion of demographic states are closely related to landscape types. The possible causes of this are discussed. The landscape units can be used as global variables to assess outbreak risk a…
Determining stingray movement patterns in a wave-swept coastal zone using a blimp for continuous aerial video surveillance
2020
Stingrays play a key role in the regulation of nearshore ecosystems. However, their movement ecology in high-energy surf areas remains largely unknown due to the notorious difficulties in conducting research in these environments. Using a blimp as an aerial platform for video surveillance, we overcame some of the limitations of other tracking methods, such as the use of tags and drones. This novel technology offered near-continuous coverage to characterise the fine-scale movements of stingrays in a surf area in Kiama, Australia, without any invasive procedures. A total of 98 stingray tracks were recorded, providing 6 h 27 min of movement paths. The tracking data suggest that stingrays may u…
Grazers increase β-diversity of vascular plants and bryophytes in wood-pastures
2016
Questions How does the presence of grazers impact plant diversity at various spatial scales? What are the effects on plant β-diversity and its two components, species turnover and nestedness? Are the effects caused by defoliation, trampling or defecating? Location Twenty-four currently grazed and 24 abandoned wood-pasture sites in Central Finland. Methods The species richness of vascular plants and bryophytes was studied at four spatial scales: within 4-m2 subplots (α1), within 100-m2 plots (α2), within sites (α3) and within the landscape (γ). β-Diversity was studied between subplots within plots (β1), between plots within sites (β2) and between sites within the landscape (β3). Results Curr…
Spatial pattern of the threatened epiphytic bryophyte Neckera pennata at two scales in a fragmented boreal forest
1999
The spatial pattern and occurrence of a threatened bryophyte, Neckera pennata, were studied in relation to the abundance and pattern of suitable substrate trees at two spatial scales: I) in a 4 x 4 km fraction of fragmented, mostly managed southern boreal forest landscape, and 2) in an old-growth forest stand within this landscape, with abundant occurrence of suitable habitats. To explore in detail the spatial clustering of N. pennata at the forest stand scale, we applied a second order point process analysis based on the Ripley's K-function for binary point patterns. Neckera pennata proved to be a rare species in the studied landscape: it was found only on 31 Populus tremula trees. At the …
Comparative analysis of abundance–occupancy relationships for species at risk at both broad taxonomic and spatial scales
2015
The abundance–occupancy relationship is one of the most well-examined relationships in ecology. At the species level, a positive association has been widely documented. However, until recently, research on the nature of this relationship at broad taxonomic and spatial scales has been limited. Here, we perform a comparative analysis of 12 taxonomic groups across a large spatial scale (Canada), using data on Canadian species at risk: amphibians, arthropods, birds, freshwater fishes, lichens, marine fishes, marine mammals, molluscs, mosses, reptiles, terrestrial mammals, and vascular plants. We find a significantly positive relationship in all taxonomic groups with the exception of freshwater…