The environmental yardstick for pesticides has been developed as a tool for farmers to select pesticides with the least environmental impact and to quantify the impact of their use at the crop/farm level, regional level and national level. For each pesticide the yardstick assigns environmental impact points for the risk to water organisms, the risk of groundwater contamination and the risk to soil organisms. It is presently used in the Netherlands as a management tool for farmers and technical consultants, as a tool for monitoring the environmental performance of farmers, as a tool for setting standards for ecolabels and as a policy evaluation tool. 相似文献
The presented paper analyses the relations between four features of geomorphology, i.e. aspect, slope, elevation and type of terrain, and tree layer diversity of forest ecosystems. The forest stand diversity is quantified by nine species diversity indices (N0, R1, R2, H, N1, N2, E1, E3, E5). The data used in this study come from the regional forest inventory of the Forest School Enterprise, Technical University Zvolen, Slovakia. Within this inventory, 26 permanent tracts were established in the systematic grid of 2×2 km, whereby a total of 120 sample plots were created on which 1,728 trees were measured. Analyses showed that species diversity is closely related only to elevation. However, the relationships of the individual species diversity indices to elevation are loose since the correlation coefficients do not exceed values of 0.30–0.40. The second part of this work presents spatial interpolation of species diversity degrees on a regional level using geostatistical methods. For this regionalisation, we used an indicator kriging. The final kriging map was found to be a suitable tool for the interpretation of tree species diversity over the investigated area. 相似文献
Data were analysed on the volume of dead wood in 86 beech forest reserves, covering most of the range of European beech forests. The mean volume was 130 m3/ha and the variation among reserves was high, ranging from almost nil to 550 m3/ha. The volume depended significantly on forest type, age since reserve establishment and volume of living wood. More dead wood was found in montane (rather than lowland/submontane) reserves, longer-established reserves (time since designation) and reserves with higher volumes of living wood.
On average, fallen dead wood contributed more to the total dead wood volume than standing dead wood. The percentage of dead wood that was standing was almost twice as high in montane than in lowland/submontane forest reserves (45% versus 25%). The volume of dead wood at selected sites changed considerably over time. The fluctuations were significantly higher in lowland/submontane than montane reserves, possibly connected with differences in the disturbance regimes and especially damage caused by windstorms. In NW Europe, the blow down of formerly managed, even-aged stands led to extraordinary high volumes of dead wood shortly after reserve establishment.
The implications for forest management and biodiversity conservation are discussed. An increase in dead wood volumes must be carried out in accordance with the local/regional forest type and disturbance regime. Thus, in order to fulfil the requirements of as many wood-depending organisms as possible, it is important to preserve not only larger amounts of dead wood, but also dead wood of different types and dimensions as well as securing a long-term continuity of dead wood. 相似文献
Management, operation and maintenance services of about 1.7 million ha irrigation areas, constructed the scheme by State Hydraulic
Works (DSI) were turned over to Water User Association (WUA) in Turkey. The number of the WUAs is 330 in Turkey for 2005.
There is therefore an urgent need to study methods of measurement and evaluation of financial performance of WUA in order
to improve the financial performance and raise the management level of WUA. This paper proposes 12 financial indicators in
order to measure and evaluate the financial performance of WUAs. Based on the results in four irrigation schemes and WUAs
in Great Menderes basin, Turkey, the methods of measurement and calculation of financial performance indicators selected,
and difference factor value related to each indicator are presented. Several financial performance indicators and difference
factor values varied widely 1999 to 2004. Therefore, these financial performance indicators should be carefully evaluated
and monitored for financial sustainability of WUAs. 相似文献