Plantas invasoras no sul de Portugal: uma abordagem biogeogr��fica

As esp��cies invasoras s��o uma das principais amea��as �� biodiversidade causando impactes ecol��gicos, econ��micos e nos servi��os dos ecossistemas. O conhecimento conjunto da din��mica das s��ries de vegeta����o e da ecologia das plantas invasoras �� uma ferramenta ��til na recupera����o ecol��gica de ��reas invadidas e na preven����o de invas��es. Este trabalho tem como objectivo principal averiguar a rela����o entre a distribui����o das plantas invasoras e as comunidades vegetais terrestres do Sul de Portugal. Para tal, fez-se corresponder a distribui����o de nove plantas invasoras selecionadas com as s��ries de vegeta����o e territ��rios biogeogr��ficos, em 60 quadr��culas com 1 Km2. A Prov��ncia Lusitana-Andaluza Costeira revelou-se a mais invadida, com predom��nio de Acacia dealbata, Acacia longifolia e Opuntia maxima no potencial climat��filo de sobreiral psam��filo; A. longifolia dominou no potencial edafoxer��filo de zimbral de Juniperus turbinata e A. dealbata e Arundo donax no potencial edafo-higr��filo de freixial. Com base nos resultados, estabeleceram-se ��reas priorit��rias para interven����o; INVASIVE PLANTS IN SOUTHERN PORTUGAL A BIOGEOGRAPHICAL APPROACH Abstract: Invasive species are one of the main threats to biodiversity worldwide and are responsible for negative impacts at ecological, economic and ecosystem services level. Complementarity between vegetation series dynamics and invasive plants ecology knowledge is essential to address ecological restoration and to prevent invasions. The main goal of this work is to investigate the relationship between invasive plants distribution and terrestrial plant communities of Southern Portugal. Fieldwork was conducted in 60 1 Km2 sampling plots and a correspondence was made between nine selected invasive plants and the vegetation series and the biogegraphic units The Andalusian-Lusitanian Coastal province was the most invaded biogeographic unit and revealed the dominance of Acacia dealbata, Acacia longifolia and Opuntia maxima in the cork oak psammophilous series; A. longifolia dominated in the maritime turbinate juniper edapho-xerophilous series and A. dealbata and Arundo donax in the ash edaphohygrophilous groves potential. Based on the results, priority areas for intervention were defined.

Recovery of degraded areas due to nickel mining by using native species of Brazilian Savannah, Barro Alto, GO.

2016

Impacts of climate change and species distribution modelling: future scenarios to endangered species in South Brazil.

2016

Population dynamics of Tachigali rubiginosa (Mart. ex Tul.). Oliveira-Filho (Fabaceae) (2007-2014) in the Forest Gallery / Ecotone / Campo Sujo transition at ��gua Limpa Farm, Federal District, Brazil.

2016

Establishment of Cerrado native species after direct seeding on abandoned pasture in the Federal District.

2016

Effect of plant architecture on the structure of epiphytic macro invertebrate communities in a Chinese lake

We examined the effect of different plant architecture types on epiphytic macroinvertebrates of a shallow macrophyte-dominated lake in China. Macroinvertebrates were sampled from four dominant submersed macrophytes in the lake - two dissected plants (Myriophyllum spicatum L. and Ceratophyllum demersum L.) and two undissected plants (Potamogeton maackianus A. Benn. and Vallisneria spiralis L.). Macro invertebrate richness showed significant differences among four submersed macrophyte habitats, and higher density per g of dry plant were associated with dissected plants than undissected plants. The average abundance in dissected plants was as three-six times as in undissected plants. The biodiversity of epiphytic macroinvertebrates was higher in dissected plants than undissected plants. Our results suggest that dissected plants provide different habitat for macroinvertebrates than dissected plant, and this concurs with the hypothesis that the former could support more epiphytic macroinvertebrates than the latter.

Response of plant-pollinator communities to fire: changes in diversity, abundance and floral reward structure

Globally, plant-pollinator communities are subject to a diverse array of perturbations and in many temperate and semi-arid systems fire is a dominant structuring force. We present a novel and highly integrated approach, which quantifies, in parallel, the response to fire of pollinator communities, floral communities and floral reward structure. Mt Carmel, Israel is a recognised bee-flower biodiversity hotspot, and using a chronosequence of habitats with differing post-fire ages, we follow the changes in plant-pollinator community organisation from immediately following a burn until full regeneration of vegetation. Initially, fire has a catastrophic effect on these communities, however, recovery is rapid with a peak in diversity of both flowers and bees in the first 2 years post-fire, followed by a steady decline over the next 50 years. The regeneration of floral communities is closely matched by that of their principal pollinators. At the community level we quantify, per unit area of habitat, key parameters of nectar and pollen forage known to be of importance in structuring pollinator communities. Nectar Volume, nectar water content, nectar concentration and the diversity of nectar foraging niches are all greatest immediately following fire with a steady decrease as regeneration proceeds. Temporal changes in energy availability for nectar, pollen, total energy (nectar + pollen) and relative importance of pollen to nectar energy show a similar general decline with site age, however, the pattern is less clear owing to the highly patchy distribution of floral resources. Changes in floral reward structure reflect the general shift from annuals (generally low-reward open access flowers) to perennials (mostly high-reward and restricted access flowers) as post-fire regeneration ensues. The impact of fire on floral communities and their associated rewards have clear implications for pollinator community structure and we discuss this and the role of other disturbance factors on these systems.

The effects of cattle grazing on plant-pollinator communities in a fragmented Mediterranean landscape

The main aims of this study were to assess grazing impacts on bee communities in fragmented mediterranean shrubland (phrygana) and woodland habitats that also experience frequent wildfires, and to explain the mechanisms by which these impacts occur. Fieldwork was carried out in 1999 and 2000 on Mount Carmel, in northern Israel, a known hot-spot for bee diversity. Habitats with a range of post-burn ages and varying intensities of cattle grazing were surveyed by transect recording, grazing levels, and the diversity and abundance of both flowers and bees were measured. The species richness of both bees and flowers were highest at moderate to high grazing intensities, and path-analysis indicated that the effects of both grazing and fire on bee diversity were mediated mainly through changes in flower diversity, herb flowers being more important than shrubs. The abundance of bees increased with intensified grazing pressure even at the highest levels surveyed. Surprisingly though, changes in bee abundance at high grazing levels were not caused directly by changes in flower cover. The variation in bee abundance may have been due to higher numbers of solitary bees from the family Halictidae in grazed sites, where compacted ground (nesting resource) and composites (forage resource) were abundant. The effects of grazing on plants were clearest in the intermediate-aged sites, where cattle inhibited the growth of some of the dominant shrubs, creating or maintaining more open patches where light-demanding herbs could grow, thus allowing a diverse flora to develop. Overall, bee communities benefit from a relatively high level of grazing in phrygana. Although bee and flower diversity may decrease under very heavy grazing, the present levels of grazing on Mount Carmel appear to have only beneficial effects on the bee community.

Abiotic drivers and plant traits explain landscape-scale patterns in soil microbial communities

The controls on aboveground community composition and diversity have been extensively studied, but our understanding of the drivers of belowground microbial communities is relatively lacking, despite their importance for ecosystem functioning. In this study, we fitted statistical models to explain landscape-scale variation in soil microbial community composition using data from 180 sites covering a broad range of grassland types, soil and climatic conditions in England. We found that variation in soil microbial communities was explained by abiotic factors like climate, pH and soil properties. Biotic factors, namely community- weighted means (CWM) of plant functional traits, also explained variation in soil microbial communities. In particular, more bacterial-dominated microbial communities were associated with exploitative plant traits versus fungal-dominated communities with resource-conservative traits, showing that plant functional traits and soil microbial communities are closely related at the landscape scale.

Spatial heterogeneity of soil nutrients and plant species in herb-dominated communities of contrasting land use

Recent interest in spatial pattern in terrestrial ecosystems has come from an awareness of theintimate relationship between spatial heterogeneity of soil resources and maintenance of plant species diversity. Soil and vegetation can vary spatially inresponse to several state factors of the system. In this study, we examined fine-scale spatial variability of soil nutrients and vascular plant species in contrasting herb-dominated communities (a pasture and an oldfield) to determine degree of spatial dependenceamong soil variables and plant community characteristics within these communities by sampling at 1-m intervals. Each site was divided into 25 1-m 2 plots. Mineral soil was sampled (2-cm diameter, 5-cm depth) from each of four 0.25-m2 quarters and combined into a single composite sample per plot. Soil organic matter was measured as loss-on-ignition. Extractable NH4 and NO3 were determined before and after laboratory incubation to determine potential net N mineralization and nitrification. Cations were analyzed using inductively coupled plasma emission spectrometry. Vegetation was assessed using estimated percent cover. Most soiland plant variables exhibited sharp contrasts betweenpasture and old-field sites, with the old field having significantly higher net N mineralization/nitrification, pH, Ca, Mg, Al, plant cover, and species diversity, richness, and evenness. Multiple regressions revealedthat all plant variables (species diversity, richness,evenness, and cover) were significantly related to soil characteristics (available nitrogen, organic matter,moisture, pH, Ca, and Mg) in the pasture; in the old field only cover was significantly related to soil characteristics (organic matter and moisture). Both sites contrasted sharply with respect to spatial pattern of soil variables, with the old field exhibiting a higher degree of spatial dependence. These results demonstrate that land-use practices can exert profound influence on spatial heterogeneity of both soil properties and vegetation in herb-dominated communities.