Search results for "Species composition"
showing 7 items of 7 documents
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…
Biogeographic patterns of base-rich fen vegetation across Europe
2014
International audience; Questions: What is the distribution of base-rich fen vegetation and the specia- list species along European biogeographic regions? How do the gradients in spe- cies composition correlate to geography and climate at continental scale? What are the implications of such patterns for the classification of these habitats?Location: Fifteen countries of Central, Western and Northern Europe.Methods: We compiled a vegetation plot database of base-rich fens and related communities including vascular plants and bryophytes. The initial data set with 6943 plots was filtered according to the presence of specialists using discriminant analysis. We used DCA to analyse the correlatio…
The Influence of Solar Power Plants on Microclimatic Conditions and the Biotic Community in Chilean Desert Environments
2016
The renewable energy sector is growing at a rapid pace in northern Chile and the solar energy potential is one of the best worldwide. Therefore, many types of solar power plant facilities are being built to take advantage of this renewable energy resource. Solar energy is considered a clean source of energy, but there are potential environmental effects of solar technology, such as landscape fragmentation, extinction of local biota, microclimate changes, among others. To be able to minimize environmental impacts of solar power plants, it is important to know what kind of environmental conditions solar power plants create. This study provides information about abiotic and biotic conditions i…
Structural and functional organization of fish assemblages in a Mediterranean shallow CO2 vent.
2017
Gli effetti dell’acidificazione degli oceani a livello globale hanno richiamato l’attenzione degli scienziati su dei sistemi marini naturali quali i vent superficiali di CO₂. Si tratta di mesocosmi naturali, in quanto su piccole scale spaziali (anche di pochi metri) si osservano marcati gradienti di pH, dove poter testare ipotesi ecologiche dell’acidificazione delle acque marine. Obiettivo della tesi è studiare le risposte della popolazione ittica alla riduzione del pH in vent superficiali mediterranei utilizzando numerosi descrittori, quali la struttura di comunità, l’organizzazione trofica, le caratteristiche e la composizione chimica delle strutture carbonatiche. Inoltre poiché i vent so…
Cross-taxon congruence and relationships to stand characteristics of vascular plants, bryophytes, polyporous fungi and beetles in mature managed bore…
2018
Abstract Multi-taxon analyses of ecological assemblages are needed when the effects of forestry on biodiversity are examined. Management usually simplifies the structure of forests, which results in quantitative and qualitative declines in many microhabitats and species associated with them. In Fennoscandia, most forests are managed for industrial use of wood, but relatively little is known about the relationships between structural components and biodiversity in managed forests. Abundance, composition or species number of different species groups reacting similarly to variation in their environment would be a useful tool e.g. in estimating responses of species that are more difficult to sa…
Ravinnetason ja ojituksen vaikutus suokasvillisuuden monimuotoisuuteen ja lajikoostumukseen
2013
Lajistollisessa monimuotoisuudessa on havaittavissa ajallista ja paikallista vaihtelua, joka on jo vuosisatojen ajan innoittanut ekologeja selvittämään lajirikkauden määrittäviä tekijöitä. Muun muassa pinta-alan, elinympäristön heterogeenisyyden, energian ja resurssien saatavuuden sekä erilaisten häiriöiden on havaittu vaikuttavan lajistolliseen monimuotoisuuteen. Osa monimuotoisuuteen vaikuttavista prosesseista on yhä huonosti tunnettuja, ja yksittäisen tekijän vaikutusta voi olla vaikea tulkita, sillä eri tekijät ovat keskenään vuorovaikutuksessa. Tämän tutkimuksen tavoitteena oli selvittää suokasvillisuusyhteisöjen avulla, vaikuttavatko resurssit tai häiriö (1) yhteisön lajimäärään (alfa…
Temporal and spatial variation of the algal community in a southern Mediterranean shallow system
2010
The algal community of a shallow system located in Western Sicily (Mediterranean Sea) has been investigated over 1 year in eight ponds (fredde). The spatio-temporal variation in total algal coverage, species richness and coverage in relation to environmental variables has been analysed. The algal community was very species-poor. A total of 50 taxa, mainly detached algae, were identified. A dominance of filamentous and foliose taxa was observed. Significant spatio-temporal differences in total algal coverage, species richness and coverage between the ponds of group A and those of group B were found. The separation into groups A and B was made a priori on the basis of different levels of prox…