Evaluation of restoration success in alluvial grasslands under contrasting flooding regimes

Along the northern Upper Rhine, Germany, large-scaled restoration attempts aiming at the recovery of species-rich alluvial meadows from ex-arable fields were evaluated. We analysed floristic composition, soil nutrient status and biomass production of old and newly established meadows with respect to their position in both, the recent functional flood-plain and the fossil flood-plain compartment which is protected from flooding by a dyke. It is hypothesised that restoration in terms of species-enrichment will be more successful in the functional floodplain due to the input of propagules in the course of flooding events.Generally, we found great floristic differences between old and new meadows, independent of their position in the floodplain. After 15-20 years of restoration management, the floristic structure of new meadows was still dominated by sown grasses and a high proportion of ruderal and arable species, whereas target species of flood-meadows largely failed to establish in both compartments. Old and new meadows differed only slightly in the environmental variables, while measured significant differences in plant available phosphorus and biomass yield were revealed between floodplain compartments.The results indicated a minor effect of edaphic site conditions on the low restoration success and limited dispersal and recruitment were revealed to be the main constraints for restoration. We found no evidence that species enrichment is enhanced in the functional floodplain via the input of diaspores by flooding. Our results strongly suggest that dispersal limitation of target species is unlikely to be overcome merely by the restoration of more natural flooding conditions.     

Too hot to handle: summer space use shift in a cold-adapted ungulate at the edge of its range

Landscape Ecology - Global warming has been exerting an increasing stress on mammal populations occurring at the bioclimatic edges of their ranges. Moose, as heat-sensitive ungulates, are expected...     

Potassium efficiency mechanisms of wheat,barley, and sugar beet grown on a K fixing soil under controlled conditions

Plant species differ in their potassium (K) efficiency, but the mechanisms are not clearly documented and understood. Therefore, K efficiency of spring wheat, spring barley, and sugar beet was studied under controlled conditions on a K fixing sandy clay loam. The effect of four K concentrations in soil solution ranging from low (5 and 20 μM K) to high (2.65 and 10 mM K) on plant growth and K uptake was investigated at 3 harvest dates (14, 21, and 31 days after sowing). The following parameters were determined: shoot dry matter (DM), K concentration in shoot dry matter, root length (RL), root length/shoot weight ratio (RSR), shoot growth rate/average root length ratio (GR_s/aRL), K influx, and soil solution K concentrations. Wheat proved to have a higher agronomic K efficiency than barley and sugar beet, indicated by a greater relative yield under K‐deficient conditions. As compared to both cereals, sugar beet was characterized by higher K concentrations in the shoot dry matter, only 30—50 % of the root length, 15—30 % of the RSR and a 3 to 6 times higher GR_s/aRL. This means that the shoot of sugar beet had a 3 to 6 times higher K demand per unit root length. Even at low K concentrations in the soil solution, sugar beet had a 7 to 10 times higher K influx than the cereals, indicating that sugar beet was more effective in removing low available soil K. Wheat and barley were characterized by slow shoot growth, low internal K requirement, i.e. high K utilization efficiency, and high RSR, resulting in a low K demand per unit root length. At low soil K concentrations, both cereals increased K influx with age, an indication of adaptation to K deficiency. The mechanism of this adaptation merits closer investigation. Model calculations were performed to estimate the K concentration difference between the bulk soil and the root surface (ΔC_L) needed to drive the measured K influx. For the two cereals, the calculated ΔC_L was smaller than the K concentration in the soil solution, but for sugar beet, ΔC_L was up to seven times higher. This indicates that sugar beet was able to mobilize K in the rhizosphere, but the mechanisms responsible for this mobilization remain to be studied.     

Overview on urban nature conservation: situation in the western-grassland biome of South Africa

Urban nature conservation issues in South Africa are overshadowed by the goal to improve human well-being, which focuses on aspects such as poverty, equity, redistribution of wealth and wealth creation. The growing need for urban employment is closely associated with the increase of squatting and informal settlements along the urban fringe, which contributes to habitat fragmentation and sprawling of cities. This increasing urbanisation is one of the main threats to biodiversity in the Grassland biome as the natural vegetation in and around cities in the North-West Province of South Africa is destroyed at an alarming rate. The lack of detailed ecological data is a major problem in the implementation of conservation-orientated policies in urban planning and management. This paper gives a brief overview of urban nature conservation in the world, the obstacles to implementation in South Africa and the importance of socio-economics and environmental legislation. We focus specifically on projects involving phytosociological studies and biotope mapping in cities in the western Grassland Biome of the North West Province. The visible presence of native vegetation is essential and integral to urban nature conservation. There is a vital need to present urban environmental data in a format that is convincing and useful to decision makers. We propose an integrated approach towards urban ecological studies culminating in effective urban nature conservation.     

Two Severe Cases of Tungiasis in Goat Kids in Uganda

Tungiasis ensues from the penetration and burrowing of female sand fleas (Tunga spp.; Siphonaptera: Tungidae) in the skin of mammals. There are few case reports of severe tungiasis in goats and in these cases the Tunga species were not in most cases clearly identified. Two cases of severe tungiasis caused by Tunga penetrans in goat kids from tungiasis-endemic rural Uganda are reported. These are the first severe cases of tungiasis in goats reported from outside South America.     

Spatial and temporal characteristics of the damage caused by wild ungulates in maize (Zea mays L.) crops

Agricultural damage caused by wild ungulates can be economically very important worldwide. In Europe, the impact of wild ungulates causes significant losses to crops, mainly to maize, where it exceeds billions of US dollars annually. The objective of this study was to explore the spatial and temporal characteristics of damage caused by wild boar and red deer to maize, in order to propose efficient prevention and mitigation of losses to agricultural producers worldwide. The study was carried out in three forests neighbouring maize fields in two different areas. We recorded data on the proportion, type and the location of the damage by ungulates within the fields. According to our results the damage varied greatly along the vegetation growth period (from green plant to corncob), likely due to the changes in the food supply provided by maize. The proportion of damaged plants increased through the growing season and was probably affected by the appearance of corncobs. Seventy to 90% of the total damage occurred within a 300 m distance to the forest edge. Considering these findings, we propose to arrange a protocol for damage prevention based on damage risk maps.     

Availability in Soil and Acquisition by Plants as the Basis for Phosphorus and Potassium supply to Plants

This report summarizes research aimed at describing the processes and quantifying the factors affecting transfer of P and K from soil into plants. Soil properties related to availability and plant properties reflecting nutrient acquisition were determined. Their interactions in the rhizosphere and their importance for nutrient supply of plants were studied by a combination of measurements and calculations using a simulation model. Phosphorus and potassium uptake by roots decreased P and K concentration at the root surface and caused characteristic depletion profiles in the adjacent soil. The shape of the profiles depended on the effective diffusion coefficient, the concentration of the nutrient in soil, morphological properties of the roots and on influx into roots. The degree of depletion at the root surface indicated the proportion of the nutrient potentially available in the soil. The shape of the depletion profiles reflected the amount of the nutrient taken up by a root section. The parameters found to describe nutrient acquisition are (i) influx per unit root length, (ii) root length per unit shoot weight (root/shoot ratio), and (iii) the period of time a root section absorbs nutrients. Plant species differed considerably in these properties. In order to integrate the processes involved and to evaluate the importance of individual factors, the Claassen-Barber model was used. Depletion profiles and nutrient uptake calculated with this model were in good agreement with measured values in a number of cases. However, at low P supply, plants absorbed substantially more P than the model predicted. This indicates that influx in this case is supported by mechanisms not properly taken into account yet. Influx per unit root length depends on morphological properties of and nutrient mobilization by roots. Root hairs increase root surface area per unit root length. In addition, because of their small diameter and geometric arrangement in soil, root hairs are specially apt to gain from diffusion when concentration gradients are small. This applies even more to VA-mycorrhizae. Their hyphae are longer and thinner than root hairs and can thus deplete larger volumes of soil per unit root length. Root-induced changes of soil pH increased the size of P depletion profiles, indicating that roots can mobilize soil P by this mechanism. Both acid and alkaline phosphatase enzyme activities were found to be markedly increased at the soil-root interface suggesting that soil organic P may contribute to the P supply of plants.     

Prevalence of feline coronavirus types I and II in cats with histopathologically verified feline infectious peritonitis

Feline coronaviruses (FCoV) vary widely in virulence causing a spectrum of clinical manifestations reaching from subclinical course to fatal feline infectious peritonitis (FIP). Independent of virulence variations they are separated into two different types, type I, the original FCoV, and type II, which is closely related to canine coronavirus (CCV). The prevalence of FCoV types in Austrian cat populations without FIP has been surveyed recently indicating that type I infections predominate. The distribution of FCoV types in cats, which had succumbed to FIP, however, was fairly unknown. PCR assays have been developed amplifying parts of the spike protein gene. Type-specific primer pairs were designed, generating PCR products of different sizes. A total of 94 organ pools of cats with histopathologically verified FIP was tested. A clear differentiation was achieved in 74 cats, 86% of them were type I positive, 7% type II positive, and 7% were positive for both types. These findings demonstrate that in FIP cases FCoV type I predominates, too, nonetheless, in 14% of the cases FCoV type II was detected, suggesting its causative involvement in cases of FIP.     

Antibody titer against bovine viral diarrhea virus (BVDV) in bulk milk samples from Bavaria

A total of 5204 bulk milk samples were tested for antibodies against bovine viral diarrhea virus (BVDV) classified according to the scheme after Alenius. Forty-five percent of the samples from 2002 were classified as class 0 and class 1, 55% as class 2 and 3. 6420 bulk milk samples from 1997 were classified in an independent study in 65.6% class 0 and 1 and 34.4% in class 2 and 3. In class 0 and class 1 farms only very rarely persistent viremic animals have been found, whereas in class 2 and 3 their presence is highly likely. Our studies with non-selected sera defined the serological screening of bulk milk samples as a promising tool for a possible BVDV eradication program in Bavaria.