In this article, we investigate the potential for detection and characterization of sinkholes under dense forest cover by using airborne laser scanning data. Laser pulse returns from the ground provide important data for the estimation of digital elevation model (DEM), which can be used for further processing. The main objectives of this study were to map and determine the geomorphometric characteristics of a large number of sinkholes and to investigate the correlations between geomorphology and vegetation in areas with such characteristics. The selected study area has very low anthropogenic influences and is particularly suitable for studying undisturbed karst sinkholes. The information extracted from this study regarding the shapes and depths of sinkholes show significant directionality for both orientation of sinkholes and their distribution over the area. Furthermore, significant differences in vegetation diversity and composition occur inside and outside the sinkholes, which indicates their presence has important ecological impacts. 相似文献
Species- and trait-environment linkages in forest plant communities continue to be a frequent topic in ecological research. We studied the dependence of floristic and functional trait composition on environmental factors, namely local soil properties, overstory characteristics, climatic parameters and other abiotic and biotic variables. The study area comprised 50 monitoring plots across Slovenia, belonging to the EU ICP Forests monitoring network. Vegetation was surveyed in accordance with harmonized protocols, and environmental variables were either measured or estimated during vegetation sampling. Significant predictors of species composition were identified by canonical correspondence analysis. Correlations between plant traits, i.e. plant growth habit, life form, flowering features and CSR signature, were examined with fourth-corner analysis and linear regressions. Our results show that variation in floristic composition was mainly explained by climatic parameters (mean annual temperature, mean annual precipitation), soil properties (pH) and tree layer-dependent light conditions. Trait composition was most closely related with tree layer characteristics, such as shade-casting ability (SCA, a proxy for light availability in the understory layer), tree species richness and tree species composition. Amongst soil properties, total nitrogen content and soil texture (proportion of clay) were most frequently correlated with different species traits or trait states. The CSR signature of herb communities was associated with tree layer SCA, soil pH and mean annual temperature. The floristic composition of the studied herb-layer vegetation depended on temperature and precipitation, which are likely to be influenced by ongoing climate change (warming and drying). Trait composition exhibited significant links to tree layer characteristics and soil conditions, which are in turn directly modified by forest management interventions.
Monitoring of biodiversity at the level of habitats is becoming increasingly common. Here we describe current practices in
habitat monitoring based on 150 schemes in Europe. Most schemes were initiated after 1990 in response to EU nature directives
or habitat management/restoration actions, with funding mostly from European or national sources. Schemes usually monitor
both the spatial distribution and the quality of the habitats, and they frequently collect data on environmental parameters
and potential causes of changes. Many schemes are local or regional rather than national or international in scope, and sampling
effort varies greatly across spatial and temporal scales. Experimental design is used in half of the schemes, however, data
are rarely analysed by advanced statistics. Most schemes require two months or less per year in manpower and are typically
run by professionals rather than by volunteers. Estimated salaries plus equipment costs average 650,000 Euro per year per
scheme, and add up to 80 million Euros annually. Costs are particularly high for schemes based on European or international
law and for schemes funded by European or national sources. Costs are also high in schemes in which sampling sites are selected
subjectively rather than based on sampling theory, and in schemes that do not use field mapping or remote sensing to document
spatial variation in habitats. Our survey demonstrates promising developments in European habitat monitoring but also underlines
the need for better spatial coverage, documentation of spatial variaton, improved sampling design and advanced data analysis.
Such improvements are essential if we are to judge progress towards the 2010 biodiversity targets. 相似文献
Species occupying habitats subjected to frequent natural and/or anthropogenic changes are a challenge for conservation management. We studied one such species, Viola uliginosa, an endangered perennial wetland species typically inhabiting sporadically flooded meadows alongside rivers/lakes. In order to estimate genomic diversity, population structure, and history, we sampled five sites in Finland, three in Estonia, and one each in Slovenia, Belarus, and Poland using genomic SNP data with double‐digest restriction site‐associated DNA sequencing (ddRAD‐seq). We found monophyletic populations, high levels of inbreeding (mean population FSNP = 0.407–0.945), low effective population sizes (Ne = 0.8–50.9), indications of past demographic expansion, and rare long‐distance dispersal. Our results are important in implementing conservation strategies for V. uliginosa, which should include founding of seed banks, ex situ cultivations, and reintroductions with individuals of proper origin, combined with continuous population monitoring and habitat management. 相似文献
The monitoring of biodiversity at the level of habitats is becoming widespread in Europe and elsewhere as countries establish
national habitat monitoring systems and various organisations initiate regional and local schemes. Parallel to this growth,
it is increasingly important to address biodiversity changes on large spatial (e.g. continental) and temporal (e.g. decade-long)
scales, which requires the integration of currently ongoing monitoring efforts. Here we review habitat monitoring and develop
a framework for integrating data or activities across habitat monitoring schemes. We first identify three basic properties
of monitoring activities: spatial aspect (explicitly spatial vs. non-spatial), documentation of spatial variation (field mapping
vs. remote sensing) and coverage of habitats (all habitats or specific habitats in an area), and six classes of monitoring
schemes based on these properties. Then we explore tasks essential for integrating schemes both within and across the major
classes. Finally, we evaluate the need and potential for integration of currently existing schemes by drawing on data collected
on European habitat monitoring in the EuMon project. Our results suggest a dire need for integration if we are to measure
biodiversity changes across large spatial and temporal scales regarding the 2010 target and beyond. We also make recommendations
for an integrated pan-European habitat monitoring scheme. Such a scheme should be based on remote sensing to record changes
in land cover and habitat types over large scales, with complementary field mapping using unified methodology to provide ground
truthing and to monitor small-scale changes, at least in habitat types of conservation importance. 相似文献