排序方式: 共有4条查询结果,搜索用时 78 毫秒
1
1.
Dimitrakopoulos PG Siamantziouras AS Galanidis A Mprezetou I Troumbis AY 《Environmental management》2006,37(6):826-839
We conducted a field experiment using constructed communities to test whether species richness contributed to the maintenance
of ecosystem processes under fire disturbance. We studied the effects of diversity components (i.e., species richness and
species composition) upon productivity, structural traits of vegetation, decomposition rates, and soil nutrients between burnt
and unburnt experimental Mediterranean grassland communities. Our results demonstrated that fire and species richness had
interactive effects on aboveground biomass production and canopy structure components. Fire increased biomass production of
the highest-richness communities. The effects of fire on aboveground biomass production at different levels of species richness
were derived from changes in both vertical and horizontal canopy structure of the communities. The most species-rich communities
appeared to be more resistant to fire in relation to species-poor ones, due to both compositional and richness effects. Interactive
effects of fire and species richness were not important for belowground processes. Decomposition rates increased with species
richness, related in part to increased levels of canopy structure traits. Fire increased soil nutrients and long-term decomposition
rate. Our results provide evidence that composition within richness levels had often larger effects on the stability of aboveground
ecosystem processes in the face of fire disturbance than species richness per se. 相似文献
2.
Charalampos Petsikos Panagiotis Dalias Andreas Y. Troumbis 《Agriculture, ecosystems & environment》2007,120(2-4):325-329
The present work aimed at studying the effect of Oxalis pes-caprae invasion in the herbaceous understory of olive groves in the island of Lesvos, Greece. The number of species, their biomass and dead plant material production was followed throughout the vegetative period in invaded and non-invaded plots. Species richness in the area invaded by O. pes-caprae gradually declined and was significantly smaller in comparison with the natural vegetation. Although biomass was equal in the invaded and non-invaded areas 1 month after germination, annual net primary production (NPP) was three times smaller in the invaded than the non-invaded area. Moreover, aboveground dead plant material of O. pes-caprae decomposed faster than a mixture of litter species of the natural vegetation. Lower biomass production in combination with increased decomposition rates of O. pes-caprae is expected to lead to reduced soil C sequestration in invaded areas. It was concluded that although O. pes-caprae does not add a new life form or functional type to the invaded herbaceous system it has considerable impacts on the diversity and ecosystem functions in olive groves. 相似文献
3.
Integrating Landscape Ecology and Geoinformatics to Decipher Landscape Dynamics for Regional Planning 总被引:1,自引:0,他引:1
We used remote sensing and GIS in conjunction with multivariate statistical methods to: (i) quantify landscape composition
(land cover types) and configuration (patch density, diversity, fractal dimension, contagion) for five coastal watersheds
of Kalloni gulf, Lesvos Island, Greece, in 1945, 1960, 1971, 1990 and 2002/2003, (ii) evaluate the relative importance of
physical (slope, geologic substrate, stream order) and human (road network, population density) variables on landscape composition
and configuration, and (iii) characterize processes that led to land cover changes through land cover transitions between
these five successive periods in time. Distributions of land cover types did not differ among the five time periods at the
five watersheds studied because the largest cumulative changes between 1945 and 2002/2003 did not take place at dominant land
cover types. Landscape composition related primarily to the physical attributes of the landscape. Nevertheless, increase in
population density and the road network were found to increase heterogeneity of the landscape mosaic (patchiness), complexity
of patch shape (fractal dimension), and patch disaggregation (contagion). Increase in road network was also found to increase
landscape diversity due to the creation of new patches. The main processes involved in land cover changes were plough-land
abandonment and ecological succession. Landscape dynamics during the last 50 years corroborate the ecotouristic-agrotouristic
model for regional development to reverse trends in agricultural land abandonment and human population decline and when combined
with hypothetical regulatory approaches could predict how this landscape could develop in the future, thus, providing a valuable
tool to regional planning. 相似文献
4.
Nature provides life-support services which do not merely constitute the basis for ecosystem integrity but also benefit human
societies. The importance of such multiple outputs is often ignored or underestimated in environmental planning and decision
making. The economic valuation of ecosystem functions or services has been widely used to make these benefits economically
visible and thus address this deficiency. Alternatively, the relative importance of the components of ecosystem value can
be identified and compared by means of multi-criteria evaluation. Hereupon, this article proposes a conceptual framework that
couples ecosystem function analysis, multi criteria evaluation and social research methodologies for introducing an ecosystem
function-based planning and management approach. The framework consists of five steps providing the structure of a participative
decision making process which is then tested and ratified, by applying the discrete multi-criteria method NAIADE, in the Kalloni
Natura 2000 site, on Lesbos, Greece. Three scenarios were developed and evaluated with regard to their impacts on the different
types of ecosystem functions and the social actors’ value judgements. A conflict analysis permitted the better elaboration
of the different views, outlining the coalitions formed in the local community and shaping the way towards reaching a consensus. 相似文献
1