Land cover composition determinants in the Uckermark (NE Germany) over a 220-year period

There is broad consensus that land use/cover has changed in central Europe over millennia. However, few studies have addressed the roles of the anthropogenic (socio-economic) and natural (biophysical) factors driving these changes over shorter periods (e.g., 100 years). In this study, we analyse the determinants of land cover composition at three discrete time periods (c. 1780, 1890, and 2000). We hypothesise that different anthropogenic and natural factors are the determinants of the main land cover types (arable fields, grasslands, and forests) and that the effects of natural and anthropogenic factors on the main land cover types differ among landscapes with highly dynamic and more stable forest-open land distributions. The study was carried out in the Uckermark region located in northeastern Germany. We compiled data on natural and anthropogenic factors (e.g. forest cover and number of inhabitants) of 65 municipalities in four landscape sections of equal size (10 × 10 km). Landscape sections were selected to reflect different dynamics (high/low) in conversion from forest to arable fields or grasslands and vice versa from 1780 to 2000. Averaged linear mixed-effect models explained between 7.5 and 81.2 % of the variance. The unique effect of anthropogenic factors varied from 2.1 to 18.7 % and that of natural factors varied from 0.2 to 43.4 %. In four of six models that included both types of factors, the natural factors were more influential than the anthropogenic factors. Except in three cases, anthropogenic and natural factors showed opposite effects on land cover types in more dynamic and more stable windows. Though the Uckermark region has been influenced by human activity for thousands of years, natural factors were a major determinant of land cover composition during all time periods, whereas anthropogenic factors became more important only during the latest time period under investigation.     

Better estimates of soil carbon from geographical data: a revised global approach

Mitigation and Adaptation Strategies for Global Change - Soils hold the largest pool of organic carbon (C) on Earth; yet, soil organic carbon (SOC) reservoirs are not well represented in climate...     

Pesticides in rainwater in Flanders, Belgium: results from the monitoring program 1997-2001

In 1997 the Flemish Environmental Agency (FEA) started a monitoring program "Pesticides in Rain in Flanders, Belgium". The original purpose of the monitoring program was to examine the possible occurrence of dichlorvos in rainwater and subsequent deposition. However, it was thought necessary from the beginning to monitor a wide range of pesticides. During the first year some 62 pesticides and metabolites and 9 polychlorinated biphenyls, were monitored at 4 locations. Nowadays the monitoring program has grown up to more than 100 pesticides and metabolites and 11 polychlorinated biphenyls examined at 8 different locations. Rainwater is collected continuously and samples are examined for pesticides and PCB's on a weekly basis. In agreement with other European studies pesticides are found in rainwater samples during times of application. Pesticides which are most frequently detected are [small alpha]-, [small beta]-endosulfan and endosulfan sulfate, [gamma]-HCH (lindane), dichlorvos, atrazine, diuron, DNOC, glyphosate and AMPA and isoproturon. Furthermore it was seen that most pesticides showed a deposition pattern related to local spraying operations.     

Management of transboundary water resources for water security; principles, approaches and State practice

Increasing water scarcity and stress are leading many nations to securing supplies for present and future water uses. National objectives are more and more pointed towards water security and the close links with food security and other macro-economic and sectoral aspects. Water security is seen as an important aspect of national and regional security and international positions on water often have a political dimension that reflects broader national objectives. Available options for sharing transboundary resources are established on the basis of general legal principles such as equitable utilization and absence of appreciable harmful transboundary effects downstream and others such as established historical utilization. These principles and doctrines must be fully understood by the advisers serving on the negotiating teams of international water treaties and agreements. From these perspectives, the paper recognizes the importance of the structural and strategic uncertainty in international relations. Co-ordination or harmonization of national policy, as an integrated part of, and administrated under existing frameworks for, regional co-operation are proposed as realistic, efficient and practicable approaches, alternative to more intensive co-operation and complicated planning and coordinating mechanisms. The article also highlights the need for training of legal specialists in countries which contemplate negotiating or re-negotiating water treaties or agreements.     

Evaluation of sampling methods for the estimation of structural indices in forest stands

The paper is about the accurate (i.e. unbiased and precise) and efficient estimation of structural indices in forest stands. We present SIAFOR, a computer programme for the calculation of four nearest-neighbour indices, which describe the spatial arrangement of tree positions, the distribution pattern of species, and the size differentiation between trees. The study uses SIAFOR as a sampling simulator in eight completely stem-mapped forest stands of varying area and structural complexity. We statistically evaluate two sample types (distance and plot sampling), comparing sampling error, bias and minimum sample size for index estimation. We introduce the concepts of measurement expansion factor (MEF) and design expansion factor (DEF) for the technical evaluation of sample type efficiency (optimal sample type). Results indicate that sampling error can reach high levels and that minimum sample sizes for index estimation often amply exceed the limit of 20% of tree density or 20 trees per species per hectare, that we set as the highest feasible sample size in normal situations. We found clear feasibility limits (in terms of minimal tree densities and reachable accuracy levels) for the estimation of all investigated indices. Generally, equal or higher sample sizes are needed for plot sampling than for distance sampling to reach equal accuracy levels. Nevertheless, plot sampling resulted more efficient for the estimation of tree size differentiation at low to medium accuracy levels. For all other investigated indices distance sampling resulted more efficient than plot sampling. Minimum sample size increases with accuracy and is negatively correlated with tree density. At a given accuracy level minimum sample size is highest for the estimation of relative mingling and lowest for tree size differentiation; furthermore it is generally lower in large stands than in small ones. Because of the consistency of our conclusions in all of the investigated stands, we think they apply in most stands of similar area (between 1 and 10 ha) and species diversity (not more than four species).     

Pesticides in surface water,sediment, and rainfall of the northeastern Pantanal basin,Brazil

Within the last 25 years an intensive agriculture has developed in the highland regions of Mato Grosso state (Brazil), which involves frequent pesticide use in highly mechanized cash-crop cultures. To provide information on pesticide distribution and dynamics in the northeastern Pantanal basin (located in southern Mato Grosso), we monitored 29 pesticides and 3 metabolites in surface water, sediment, and rainwater of the study area during the main application season. In environmental samples, 19 pesticides and 3 metabolites were detected in measurable quantities, resulting in at least one pesticide detection in 68% of surface water samples (n = 139), 62% of sediment samples (n = 26), and 87% of rainwater samples (n = 91). Surface water samples were most frequently contaminated by endosulfan compounds (alpha-, beta-, -sulfate), ametryn, metolachlor, and metribuzin, although in low (< 0.1 microgram L-1) concentrations. Sediment samples exhibited concentrations up to 4.5 micrograms kg-1 of p,p'-DDT, p,p'-DDE, endosulfan-sulfate, beta-endosulfan, and ametryn. In contrast, rainwater was polluted with substantial amounts of endosulfan, alachlor, metolachlor, trifluralin, monocrotofos, and profenofos (maximum concentrations = 0.3 to 2.3 micrograms L-1) in the highlands. Lowland rainwater samples taken 75 km from the next application area contained 5- to 10-fold lower mean pesticide concentration than in the highlands. Cumulative deposition rates of the pesticide sum within the study period ranged from 423 micrograms m-2 in the highlands to 14 micrograms m-2 in the lowlands. The atmospheric input of pesticides to ecosystems seemed to be of higher relevance in the tropical study area than known from temperate regions.     

Application technique and slurry co-fermentation effects on ammonia,nitrous oxide,and methane emissions after spreading: I. Ammonia volatilization

Ammonia emissions after spreading animal manure contribute a major share to N losses from agriculture. There is an increasing interest in anaerobic co-digestion of liquid manure with organic additives. This fermentation results in a change of physical and chemical parameters of the slurry. Among these are an increased pH and ammonium content, implying a higher risk of NH3 losses from fermentation products. To compare different application techniques and the effect of fermentation on NH3 volatilization, we used the standard comparison method and tested it for reliability. This method seems to be perfectly suited for experiments with a large number of treatments and replicates if prerequisites concerning the experimental layout are considered. We tested four different application techniques on arable and grassland sites. The more the substrate was incorporated into the soil or applied near the soil surface on the grassland site, the less NH3 was lost. Injection of the substrate reduced losses to less than 10% of applied NH4+ on both sites, whereas losses after splash plate application amounted to more than 30%. Trail shoe application on grassland performed as well as injection. Harrowing on arable land also reduced emissions efficiently, if harrowing occurred within the first 2 h after application. Emissions from trail hose-applied co-fermentation product were not greater than from unfermented slurry. Better infiltration of the less viscous substrate seemed to have compensated for the increased loss potential.