Search results for "community"
showing 10 items of 2132 documents
Vegetation changes in boreo–nemoral forest stands depending on soil factors and past land use during an 80 year period of no human impact
2016
Information on the long-term changes in plant communities that occur without human interference is limited, due to insufficient studies where vegetation can be resurveyed. In 1912, a strict nature protection reserve, with non-intervention management, was established on Moricsala Island in Latvia, located in the boreo–nemoral forest zone. Prior to establishment of the nature reserve, part of the island area was used for agriculture. The island is now covered almost entirely by forest dominated by Quercus robur L. and Tilia cordata Mill. on sandy soils. Resurvey was conducted in 2011 in 17 plots in which tree layers and the understory vegetation had been described in 1930. The plots were cla…
The effects of absolute and relative nutrient concentrations (N/P) on phytoplankton in a subtropical reservoir
2020
Abstract The elemental composition of phytoplankton is a critical factor for primary production and nutrient recycling. The increase anthropogenic nutrient input into freshwater ecosystems is affecting phytoplankton assemblage structure and its stoichiometry. Reservoirs of South China generally show low level of phosphate and it is not clear how phytoplankton can grow and occasionally bloom in such conditions. Therefore, an indoor experiment was conducted to investigate the response of natural phytoplankton communities to 25 levels of supplied nitrogen to phosphorus ratios (N/P), arising from the combination of 5 levels of N and P. Our aim was to check the effects of absolute and relative N…
No apparent effect of invasive alien goldenrod on soil microbial communities or soil fauna feeding activity
2020
Abstract Invasive alien species spreading in abandoned agricultural landscape may negatively affect native organisms, including plants and soil biota. This study assessed the effects of invasion by Solidago sp. (goldenrod) in southern Poland on soil fauna feeding activity and on soil microorganism activity, biomass, and functional and taxonomic diversity, in a comparisons of paired plots: goldenrod-invaded plots and nearby non-invaded plots of semi-natural grassland. Goldenrod-invaded plots had fewer vascular plant species (paired t-test) than non-invaded ones, and showed a distinct plant community composition (ANOSIM). Non-invaded and invaded plots did not differ in a range of measured soi…
Impact of drainage and hydrological restoration on vegetation structure in boreal spruce swamp forests
2014
Drainage to increase timber production is a major cause of degradation of boreal peatlands in Europe. As a consequence of the forestry drainage, the area of pristine spruce swamp forests has declined drastically in northern Europe over the past century. In restoration by rewetting, drainage ditches are blocked to restore the pre-disturbance hydrological regime and, ultimately, the biodiversity values and ecosystem functions of pristine spruce swamp forests. In this study, we quantify vegetation recovery and examine mechanisms behind the changes in plant community composition. For this, we surveyed the understorey vegetation of 9 undrained, 9 drained and 18 rewetted spruce swamp forest sites…
The mechanistic basis of changes in community assembly in relation to anthropogenic disturbance and productivity
2016
Anthropogenic disturbance often causes changes in communities. However, the mechanistic basis of these changes remains elusive. As all patterns in community ecology can be understood as a result of four processes (speciation, selection, drift, and dispersal), the effect of disturbance should depend on how disturbance disrupt these processes. We studied the effects of disturbance and productivity on species richness, community composition, and community dispersion (i.e., variation in community composition) in the vegetation of 120 boreal peatlands using null-model approach to determine whether community assembly processes differ between pristine and disturbed sites. Sites represented three p…
Guano-Derived Nutrient Subsidies Drive Food Web Structure in Coastal Ponds.
2016
A stable isotope study was carried out seasonally in three coastal ponds (Marinello system, Italy) affected by different gull guano input to investigate the effect of nutrient subsidies on food web structure and dynamics. A marked 15N enrichment occurred in the pond receiving the highest guano input, indicating that gull-derived fertilization (guanotrophication) had a strong localised effect and flowed across trophic levels. The main food web response to guanotrophication was an overall erosion of the benthic pathway in favour of the planktonic. Subsidized primary consumers, mostly deposit feeders, switched their diet according to organic matter source availability. Secondary consumers and,…
Risk of predation makes foragers less choosy about their food.
2017
18 pages; International audience; Animals foraging in the wild have to balance speed of decision making and accuracy of assessment of a food item's quality. If resource quality is important for maximizing fitness, then the duration of decision making may be in conflict with other crucial and time consuming tasks, such as anti-predator behaviours or competition monitoring. Individuals facing the risk of predation and/or competition should adjust the duration of decision making and, as a consequence, their level of choosiness for resources. When exposed to predation, the forager could either maintain its level of choosiness for food items but accept a reduction in the amount of food items con…
Mycorrhizae differentially influence the transfer of nitrogen among associated plants and their competitive relationships
2021
Abstract The formation of a common mycorrhizal network among roots of different plant species growing close to each other can influence plant community dynamics, regulating plant relationships through the differential transfer of nutrients from one plant to another. However, knowledge of the mechanisms that regulate this process is poor. Here we quantify the contribution of arbuscular mycorrhizae to the transfer of N among heterospecific plants growing adjacent to each other and examine whether the differential transfer of N within the plant community via mycorrhizae can alter competitive relationships among plant species. Plants of four species (wheat, pea, flax, and chicory) were grown in…
The buffer effect of canopy-forming algae on vermetid reefs' functioning: A multiple stressor case study.
2021
Abstract Biodiversity plays a key role for our planet by buffering ongoing and future changes in environmental conditions. We tested if canopy-forming algae enhancing biodiversity (CEB) in a Mediterranean intertidal reef ecological community could alleviate the effect of stressors (heat waves and pollution from sewage) on community metabolic rates (as expressed by oxygen consumption) used as a proxy of community functioning. CEB exerted a buffering effect related to the properties of stressor: physical-pulsing (heat wave) and chronic-trophic (sewage). After a simulated heat wave, CEB was effective in buffering the impacts of detrimental temperatures on the functioning of the community. In r…
Do invasive alien plants really threaten river bank vegetation? : a case study based on plant communities typical for Chenopodium ficifolium : an ind…
2018
Riparian zones are very rich in species but subjected to strong anthropogenic changes and extremely prone to alien plant invasions, which are considered to be a serious threat to biodiversity. Our aim was to determine the spatial distribution of Chenopodium ficifolium, a species demonstrating strong confinement to large river valleys in Central Europe and an indicator of annual pioneer nitrophilous vegetation developing on river banks, which are considered to be of importance to the European Community. Additionally, the habitat preferences of the species were analysed. Differences in the richness and abundance of species diagnostic for riverside habitats, as well as the contribution of resi…