1,721,099 research outputs found
Classification and biodiversity patterns in pastures of province of Trento
Full text linkIn the Italian Alps, summer pastures are still managed in traditional ways, which maintain important grassland habitats of many species, although the number of pastures has declined drastically over the past few decades. Research on alpine pastures is important in many respects. From the aspect of nature protection, pastures represent a habitat for numerous plant and animal species; and, through their diversity, contribute greatly to the biodiversity and scenic value of the area. From the economic standpoint, grasslands are a source of feed for stock, a habitat for medicinal and melliferous plants. They are also capable of supporting particular dairy products, high added value, because fodder obtained from natural with unique qualities and not reproducible, capable of giving products derived valuable characteristics and identification.
Land use changes constitute a threat to the persistence of these grassland ecosystems Therefore, it is very important to understand the mechanisms leading to the organization and distribution of these communities to preserve plant diversity and to develop effective agri-environment schemes, which can maintain and enhance biodiversity.
Phytosociological investigation is important to understand some aspects of the study of grasslands. As in the forestry sector, also in grasslands sector have arisen in recent years some efforts to characterize, according to a typological approach, pasture vegetation. A purpose of this research was to realize an interpretative classification of pastures of Province of Trento. Since the pastures of the study area have not been systematically investigated for a long time, the pasture vegetation of the Province of Trento was classified using numerical methods, then the results were compared with the traditional syntaxonomic system, and finally were examined the influence of ecological factors on variation in grassland vegetation.
Further aim of the research was assessed the relationship between topography, distance from the farm centre, altitude, bedrock, grazing intensity, species richness and vegetation composition across two spatial scales (within and between summer farms). A stratified random sampling design was used to collect 157 vegetation relevés along an elevation gradient. It was hypothesized that plant diversity varies in response to topography due to the highly variable alpine environment and it depends strongly not only on grazing spatial gradient from the centres of the farms to the surrounding vegetation, but also on spatial distribution of the management practices within the study region The patterns of species richness and species composition found in alpine pastures result from the interaction of different environmental and management factors operating at different spatial scales. The results indicate that at small scales (within farms) species richness is mainly determined by slope, while specie composition is controlled by distance from the farm centre as well as slope. At large scale (between farms), was observed a key role of grazing intensity and bedrock types on species diversity patterns. The results indicate that the identification of appropriate stocking rates appears to be the most promising approach to conserve the high biodiversity of alpine pastures, as both intensification and abandonment changed species composition and reduced plant species diversity.
Finally, to gain insight into the processes that may affect species diversity and functional diversity in alpine pastures, the observed local patterns of additive species diversity components (α-, β-, γ-) were analysed with respect to altitude, landscape, topographic hetereogeneity, bedrock type and grazing intensity. Additive diversity partitioning approach facilitated a quantification and comparison of the relative contributions of α- and β-diversity components to total regional diversity along an elevation gradient. Based on the results, I conclude that the observed patterns of plant species diversity appeared to be influenced by processes at multiple spatial scales. The results indicate that the maintenance of a large variety of grassland utilisation systems along with heterogeneous abiotic environmental conditions appears to be a promising tool for the conservation of species richness and functional diversity due to enhanced β-diversity among pastures parcels.Nelle Alpi italiane, gli alpeggi sono ancora gestiti in maniera tradizionale, conservando importanti habitat e specie vegetali, sebbene il numero delle malghe monticate sia diminuito drasticamente negli ultimi decenni. La ricerca sui pascoli alpini è importante sotto molti aspetti. Dal punto di vista della protezione della natura, i pascoli rappresentano l'habitat di numerose specie vegetali ed animali e attraverso la loro ricchezza di specie, contribuiscono notevolmente alla biodiversità ed al valore paesaggistico delle Alpi. Dal punto di vista economico, i pascoli sono una fonte di alimentazione per gli animali, ed habitat per piante officinali e mellifere. Sono anche in grado di supportare prodotti lattiero-casearii particolari, ad alto valore aggiunto, perché ottenuti da foraggi naturali con caratteristiche uniche e non riproducibili, in grado di dare prodotti derivati di qualità.
I cambiamenti di uso del suolo costituiscono una minaccia per la persistenza di questi ecosistemi. Pertanto, è molto importante comprendere i meccanismi che controllano l'organizzazione e la distribuzione di queste comunità, per preservare la diversità delle piante e di sviluppare efficaci schemi agro-ambientali, in grado di mantenere e migliorare la biodiversità.
L’analisi fitosociologia è importante per comprendere alcuni aspetti dello studio delle praterie. Come nel settore forestale, anche in quello pastorale sono iniziati negli ultimi anni alcuni progetti per caratterizzare, secondo un approccio tipologico, le vegetazioni pascolive. Uno degli obiettivi di questa ricerca era quello di realizzare una classificazione interpretativa dei pascoli della Provincia di Trento. Poiché i pascoli della zona oggetto di studio non sono mai stati studiati in modo sistematico, la vegetazione dei pascoli della Provincia di Trento è stata classificata utilizzando metodi numerici; i risultati sono stati confrontati con il sistema tradizionale sintassonomico e, infine, è stata analizzata l'influenza dei fattori ecologici sulla variazione della composizione floristica dei pascoli.
Un successivo obiettivo della ricerca era quello di valutare la relazione tra la topografia, la distanza dal centro aziendale, l'altitudine, il tipo di substrato geologico, l’intensità di pascolamento, la ricchezza di specie e la composizione della vegetazione attraverso due scale spaziali (all'interno e tra le malghe campionate). Un disegno sperimentale stratificato è stato utilizzato per campionare i 157 rilievi vegetazionali lungo un gradiente altitudinale. E’ stato ipotizzato che la diversità vegetale varia in risposta della topografia legata all'ampia variabilità ambientale degli ambienti alpini, e dipende in modo consistente non solo dal gradiente spaziale di pascolamento dal centro della malga alle vegetazioni marginali, ma anche dalla distribuzione spaziale delle pratiche gestionali impiegate nell’area di studio. I modelli di distribuzione della ricchezza di specie e della composizione riscontrati nei pascoli alpini derivano dall'interazione di diversi fattori ambientali e gestionali che operano a diverse scale spaziali. I risultati indicano che su piccola scala (all’interno delle malghe), la ricchezza di specie è principalmente controllata dalla pendenza, mentre la composizione vegetazionale è determinata dalla distanza dal centro della malga, e dalla pendenza. Su larga scala (tra le malghe), è stato osservato un ruolo chiave dell’intensità di pascolamento e del tipo di substrato geologico sulla ricchezza di specie. I risultati indicano che l'individuazione di appropriati indici di carico animale sembra essere l'approccio più promettente per la conservazione della biodiversità dei pascoli alpini, poiché, sia l’intensificazione gestionale che l’abbandono cambiano composizione delle specie e riducono la diversità delle specie vegetali.
Infine, al fine di conoscere i processi che possono influenzare la diversità delle specie e, la diversità funzionale nei pascoli alpini, i diversi componenti additivi della biodiversità (diversità -α, -β e -γ) sono stati analizzati in relazione all'altitudine, alle variabili del paesaggio, dell’eterogeneità topografica, del tipo di substrato geologico e l'intensità di pascolamento. L’approccio della partizione additiva della diversità facilita la quantificazione ed il confronto tra i contributi relativi delle componenti -α-e –β della diversità rispetto al totale delle diversità regionale lungo un gradiente altitudinale. Sulla base dei risultati ottenuti, è stato osservato che la diversità vegetale sembra essere influenzato dai processi operanti a differenti scale spaziali. I risultati indicano che il mantenimento di una grande varietà di tipi gestionali, insieme alle condizioni ambientali eterogenee delle zone alpine sembra essere uno degli strumenti più favorevoli per la conservazione delle ricchezza di specie e della diversità funzionale, contribuendo ad aumentare la diversità β tra i pascoli
Impact of land use intensity and temperature on the reproductive performance of Dactylis glomerata populations in the southeastern Alps
No full textAn understanding of the processes and
environmental conditions governing spatial variation
in reproductive performance of plants can provide
important information about the factors characterizing
plant community structure and influencing fitness in
natural plant populations, especially in the context of
climate and land use change. In this study, 60
mountain populations of Dactylis glomerata distributed
along a fertilization regime in varying grassland
hay meadows were evaluated. Variations in field
management, climate, soil fertility, vegetation structure,
population density and species richness on
reproductive performance were examined. The results
indicated that field management and soil nutrient
availability are the main variables influencing
population density and reproductive output of
D. glomerata. Moreover, the results show the effect
of temperature on seed mass and resource investment
in reproduction. Climate and soil change suggest a
morphological differentiation of reproductive traits:
(i) individuals grown on sites with higher soil
nutrient availability or nutrient supply have larger inflorescences with a greater number and heavier
seeds; (ii) individuals grown on warmer sites have
heavier seeds. We conclude that if the climate warms
and increases land use intensification in hay meadows
in the Alps, this will have a pronounced positive
impact on the reproductive performance of D. glomerata.
Moreover, it can be hypothesized that the
migration potential of D. glomerata towards higher
altitudes may be likely in the near future in response to
accelerated climate change
Using Natural Gradients to Infer a Potential Response to Climate Change: An Example on the Reproductive Performance of Dactylis Glomerata L.
Full text linkAn understanding of the climate conditions governing spatial variation in the reproductive performance of plants can provide important information about the factors characterizing plant community structure, especially in the context of climate change. This study focuses on the effect of climate on the sexual reproductive output of Dactylis glomerata L., a perennial grass species widely distributed throughout temperate regions. An indirect space-for-time substitution procedure was used. Sixty mountain populations of the same target species were surveyed along an elevation gradient, and then, a relevant climate model was used to infer a potential response to climate change over time. Within each population, information on the number of stems, seed number and seed mass were collected. Resource investment in reproduction (RIR) was quantified as seed number × seed mass. A clear variation was found in the reproductive performance of D. glomerata along the elevational gradient: RIR improved with increasing temperature. The best model included only one term: the maximum temperature of the warmest month. This study demonstrates that mountain ecosystems offer particularly good opportunities to study climate effects over relatively short distances and suggests that warming will enhance D. glomerata’s reproductive output throughout its elevational range. Furthermore, it can be hypothesized that a potential migration of D. glomerata toward higher altitudes may occur in response to accelerated climate change
Assessing the influence of environmental gradients on seed mass variation in mountain grasslands using a spatial phylogenetic filtering approach
Full text linkSeveral studies have demonstrated that seed mass is related to different environmental factors. However, they have taken no account of the joint effects of spatial and phylogenetic information. We analysed the distribution pattern of seed mass along an elevational gradient (1040–2380 m a.s.l.) at the community level in grasslands of the southern Alps. First, we tested the influence of environmental filters (climate and soil properties) in determining community-weighted seed mass variation in mountain grasslands. Second, we verified the relative roles of environmental filters in determining seed mass variation after accounting for spatial and phylogenetic autocorrelation with an eigenvector filtering approach. Temper- ature, soil fertility, and soil pH were the most important predictors for explaining seed mass variation; specifically, warmer, low fertility, and alkaline grasslands showed a greater seed mass. Inclusion of spatio- phylogenetic filters in the model increased its fit and the variance explained and reduced autocorrelation significantly but had substantial effects on the parameter estimates, with temperature and soil pH becom- ing insignificant. This effect may be ascribable to spatially structured phylogenetic patterns and could likely result from the common evolutionary histories shared by many species at sites with similar envi- ronmental conditions. Therefore, the observed patterns between community-weighted seed mass and both temperature and soil pH are not independent of phylogeny, but they are explained by the shared history within genera and families. Nevertheless, soil fertility remained the most important predictor for explaining seed mass variation. The results of this work contribute to better understanding the combined effects of environment and evolutionary factors for determining seed mass distributions in the spatial context of mountain grasslands. The observed relationships with climate and soil properties are partic- ularly interesting because they are potentially relevant when modelling plant trait composition under changes in land use and climate
Does residence time affect responses of alien species richness to environmental and spatial processes?
Full text linkOne of the most robust emerging generalisations in invasion biology is that the probability of invasion increases with the time since introduction (residence time). We analysed the spatial distribution of alien vascular plant species in a region of north-eastern Italy to understand the influence of residence time on patterns of alien species richness. Neophytes were grouped according to three periods of arrival in the study region (1500–1800, 1800–1900, and > 1900). We applied multiple regression (spatial and nonspatial) with hierarchical partitioning to determine the influence of climate and human pressure on species richness within the groups. We also applied variation partitioning to evaluate the relative importance of environmental and spatial processes. Temperature mainly influenced groups with species having a longer residence time, while human pressure influenced the more recently introduced species, although its influence remained significant in all groups. Partial regression analyses showed that most of the variation explained by the models is attributable to spatially structured environmental variation, while environment and space had small independent effects. However, effects independent of environment decreased, and spatially independent effects increased, from older to the more recent neophytes. Our data illustrate that the distribution of alien species richness for species that arrived recently is related to propagule pressure, availability of novel niches created by human activity, and neutral-based (dispersal limitation) processes, while climate filtering plays a key role in the distribution of species that arrived earlier. This study highlights the importance of residence time, spatial structure, and environmental conditions in the patterns of alien species richness and for a better understanding of its geographical variation
Contrasting responses of epiphytic and dead wood-dwelling lichen diversity to forest management abandonment in silver fir mature woodlands
Full text linkIn the Alps, many forests are under abandonment because of direct protection or the unprofitability of timber production. The objective of this study was to analyse the effect of silviculture abandonment on the species richness and composition of epiphytic and dead wood-dwelling lichens in silver fir woodlands. An abandoned and a currently non-intensively managed forest watershed of the eastern Italian Alps that were matched for topography, stand structure, plant community and history of use were selected and randomly sampled for the lichen diversity of their silver fir mature stands. Generalised linear mixed models were used for the analyses of the species richness, whereas the species composition patterns were explored by redundancy analysis. The diversity of both of the lichen guilds were explained by the microhabitat conditions related to the contrasting management regimes, but they had opposite responses to the abandonment of the silvicultural activities. The epiphytic lichen communities were richer in species in the managed than in the abandoned silver fir woodlands. However, the effect of a 50 year management cessation on the epiphytic lichens may change in the long term when natural disturbances create gaps and increase the attributes of old-growth forests. The dead wood-dwelling lichen species richness was higher in the abandoned forest because an increased availability of types of dead wood is usually rare in managed forests. The dead wood-dwelling lichen communities of the managed forests were a subset of a more diverse community that was developing in the abandoned forest. Our results indicated that, in non-intensively managed silver fir mature stands, lichen diversity may benefit from the retention of logs and snags, which provide habitat features typical of old-growth forests
Exploring abiotic and anthropogenic drivers of alien plant species distribution in the Alps: bioclimatic origin matters!
Full text linkPlant invasions into mountain ecosystems are influenced by interacting abiotic and biotic
processes. In order to establish and spread in a new area, alien plants must be able to tolerate the
prevailing climatic conditions, i.e., the greater the degree of climate matching between the invaded
region and the species' native region, the higher is the likelihood of establishment. In this study,
we assess the role of abiotic and anthropogenic variables driving both alien plant species richness
and composition in mountain regions. In addition, we assess whether the climatic pre-adaptation
of alien plant species determine different responses to environmental processes. The two
questions are examined using the alien flora of the European Alps. Area was the most important
predictor of alien plants distribution, followed by anthropogenic disturbance. Climatic conditions
had a smaller direct effect on species richness, while temperature appeared as a key driver in
determining community differentiation. Considering the bioclimatic origin, both temperature and
urban elements showed a significant interaction with bioclimatic origin. Only Holarctic species
show a significant negative relationship with temperature, while the effect of human pressure was
strongest for tropical species. Our results show that abiotic and anthropogenic processes affect
the distribution of alien plants in mountain ecosystems, but differently for species of different
bioclimatic origin. In particular, we showed that the climatic pre-adaptation of Holarctic species
in association with anthropogenic disturbance can increase the level of invasion of alien plants in
mountain areas. Our results also reveal a strong influence of human pressure on tropical species,
despite their low adaptability to urban conditions
A global synthesis reveals biodiversity-mediated benefits for crop production
Full text linkHuman land use threatens global biodiversity and compromises multiple ecosystem functions critical to food production. Whether crop yield–related ecosystem services can be maintained by a few dominant species or rely on high richness remains unclear. Using a global database from 89 studies (with 1475 locations), we partition the relative importance of species richness, abundance, and dominance for pollination; biological pest control; and final yields in the context of ongoing land-use change. Pollinator and enemy richness directly supported ecosystem services in addition to and independent of abundance and dominance. Up to 50% of the negative effects of landscape simplification on ecosystem services was due to richness losses of service-providing organisms, with negative consequences for crop yields. Maintaining the biodiversity of ecosystem service providers is therefore vital to sustain the flow of key agroecosystem benefits to society.EEA ConcordiaFil: Dainese, Matteo. Eurac Research. Institute for Alpine Environment; ItaliaFil: Dainese, Matteo. University of Würzburg. Biocenter. Department of Animal Ecology and Tropical Biology; AlemaniaFil: Martin, Emily A. University of Würzburg. Biocenter. Department of Animal Ecology and Tropical Biology; AlemaniaFil: Aizen, Marcelo Adrian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Aizen, Marcelo Adrian. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina.Fil: Albrecht, Matthias. Agroscope. Agroecology and Environment; SuizaFil: Bartomeus, Ignasi. CSIC. Estación Biológica de Doñana. Integrative Ecology; EspañaFil: Bommarco, Riccardo. Swedish University of Agricultural Sciences. Department of Ecology; SueciaFil: Carvalheiro, Luisa G. Universidade Federal de Goias. Departamento de Ecologia; BrasilFil: Carvalheiro, Luisa G. Universidade de Lisboa. Faculdade de Ciencias. Centre for Ecology, Evolution and Environmental Changes (CE3C); PortugalFil: Chaplin-Kramer, Rebecca. Stanford University. Natural Capital Project; Estados UnidosFil: Gagic, Vesna. Commonwealth Scientific and Industrial Research Organisation (CSIRO); AustraliaFil: Garibaldi, Lucas Alejandro. Universidad Nacional de Rio Negro. Instituto de Investigaciones de Recursos Naturales, Agroecología y Desarrollo Rural; ArgentinaFil: Garibaldi, Lucas Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Cavigliasso, Pablo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Concordia; ArgentinaFil: Steffan-Dewenter, Ingolf. University of Würzburg. Biocenter. Department of Animal Ecology and Tropical Biology; Alemani
Alien plant species distribution in the European Alps: influence of species’ climatic requirements
No full textThe paper provides the first estimate of the role of abiotic and anthropogenic variables driving both alien plant species richness and composition covering the whole region of the European Alps. To establish and spread in a new area, alien plants must be able to tolerate the prevailing climatic conditions. We therefore tested the hypothesis that climatic requirements modified by bioclimatic origin and elevational distribution influence the distribution of alien plants in the Alps. Despite most alien plant species showing a relatively restricted distribution in the Alps, some regions, however, were already more strongly invaded. Most of these species were adapted to warmer conditions, probably constrained by climatic factors. Environmental heterogeneity was the most important predictor of alien plant species richness, followed by anthropogenic disturbance. Due to the political/artificial delineation of the administrative districts in the Alps (i.e., ignoring ecological conditions) we did not find a direct influence of climatic constraints on alien distribution. Anyway, northern Holarctic alien species showed a broader climatic tolerance and the capability to grow across a wide environmental range. Our results also reveal a strong influence of human pressure on warmer tropical species, despite their low adaptability to anthropogenic habitats. To this aim, managers would profit from early warnings to prevent future invasions. Considering bioclimatic origin, our study can aid in identifying potentially invasive species in a more regional setting
Capturing cross-scalar variation of habitat selection with grid sampling: an example with hazel grouse (Tetrastes bonasia L.)
No full textThe objective of this study was to investigate a grid-based sampling design to determine the cross-scalar selection of habitat by a territorial animal species: the hazel grouse (Tetrastes bonasia L.). In each of three sites with increasing hazel grouse nest site density, three lattice grids were used to measure both the habitat variables and the species occurrence in 100 30 × 30 m cells. We calculated the average values for habitat variables, as well as use versus non-use by the species, at three spatial scales: small (1 × 1 cell), intermediate (2 × 2 cells) and large (3 × 3 cells). Generalised linear mixed models were integrated into a method of variation and hierarchical partitioning and used to assess the relationship between the habitat variables and the species preferences at each scale. In all scales, species selection was associated with ground layer composition. Selection was also associated with the composition of the woody layer and negatively associated with dominance of tor grass (Brachypodium rupestre (Host) Roem. & Schult.) at the two larger scales. Both litter cover and thinning contributed positively to the habitat selection at the two smaller scales. The other variables were significant only at one scale or explained a relatively low proportion of the variation at multiple scales. Neither the management nor the stand structure variables played a significant independent role across scales when compared with ground layer variables. The total variation explained was highest (ca. 90 %) at the large scale. This finding indicates the possibility of obtaining cross-scalar hazel grouse preferences from grid-based sampling, provided that spatial autocorrelation in the data is handled appropriately
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