Mapping Mesquite (Prosopis) Distribution and Density Using Visual Aerial Surveys

Mapping the distribution and abundance of invasive plants is a high priority, but establishing cost-effective and practical techniques at appropriate scales remains elusive. Mesquite is a highly invasive shrub that cannot currently be reliably distinguished from other plant species using remote sensing technologies, at least not at accuracies necessary for mapping mesquite at very low densities. This paper describes and tests an alternative method. A visual, aerial technique was used to map a large mesquite (Leguminoseae: Prosopis spp.) population in Australia; 216 654 ha was surveyed in 18.5-ha grid cells to include the entire population. The objective was to test the ability of this technique to detect and map mesquite at very low densities for surveillance and to assist in prioritizing management effort and, where mesquite was well established, to categorize mesquite into broad canopy cover classes for change detection and to identify habitat associations. The survey technique was very effective at detecting isolated mesquite plants (&spilt; 0.6% canopy cover across a grid cell), which is considerably better than existing remote sensing technologies. Detection of low-density mesquite was particularly important, as most occupied grid cells (55%) had isolated mesquite, and their management may offer the best return on investment. The technique was also competitive cost wise ($0.39 USD per hectare) and required relatively little expertise. Grid cells with moderate (20%–50%) to dense (&spigt; 50%) canopy covers were almost all restricted to a 32 500-ha area on the floodplain delta of the Fortescue River, where the original introductions occurred. Cover class estimates appeared to be well calibrated between observers within a survey; however, they were poorly calibrated between independently conducted surveys, suggesting that further methodological refinement is necessary if this technique is to be reliable for change detection.     

Do forest and health professionals presume that forests offer health benefits,and is cross-sectional cooperation conceivable?

In high-income countries depression and cardiovascular diseases were predicted to be the two leading causes of DALYs in the year 2030. Private-life stress fosters both kinds of diseases. Scientific findings already show that forest exposure has stress-reducing effects. Particularly in Japan, people have practiced forest bathing to improve their health. The German population also has a strong connection to its forests, and forest law allows forest access, regardless of ownership structure. Hence, the question arises of whether forest exposure could be used in Germany as a kind of stress-coping strategy. To a certain degree, the success of such a strategy in Germany would require the participation of the stakeholders that are active in both the health and the forestry sectors. Therefore, it seems necessary to gain insight into German forest and health professionals' understanding and attitude concerning forest-related health benefits. For this reason, in this pilot study, guideline interviews with professionals of both sectors and with professionals standing in between these professions were conducted, recorded and transcribed. On the one hand, each professional’s presumptions regarding the health-fostering effects of forests were investigated, derived from their subjective certainty that forest exposure has health-fostering effects. In addition, a thought experiment was used to estimate the level of willingness to cooperate with each other in order to motivate people to be physically active in forests. For analysis, Mayring’s qualitative content analysis and a frequency analysis (MaxQDA) were applied. Findings show that most of the interviewed professionals presume forests to have health-fostering effects. Furthermore, something derived from the statements within the context of the thought experiment was that most professionals seem to be willing to cooperate with the other sector. Hence, it might be conceivable that forest exposure may be part of a German stress-coping strategy.     

Relevance of rest periods in non-equilibrium rangeland systems – A modelling analysis

The worldwide loss of utilisable rangeland in (semi-) arid areas results in huge economic and social costs. Only adaptive management strategies are able to cope with these systems, which are mainly driven by unpredictable and stochastic rainfall. The aim of the study was to investigate the relevance of rest periods as part of the management scheme in these non-equilibrium rangeland systems. The starting point of the analysis is an approved management system – the Karakul sheep-breeding Gamis-Farm (Namibia). The farmer applies a flexible strategy, which combines short-term adaptation of the stocking rate to the available forage and long-term adaptation by resting a third of the paddocks in years with sufficient rainfall.We developed a simulation model that focuses on the key dynamics of this non-equilibrium system. Beginning with the strategy used by the Gamis-Farm, a set of alternative grazing strategies was defined, all adapted to the available forage but differing in whether and when resting is granted for a part of the pasture. The effectiveness of these strategies was compared according to the long-term productivity of the pasture and the farmer’s livelihood.Our results reveal ecological settings during which resting is essential for the recovery of the vegetation in a fluctuating environment, as well as those during which it is not. The growth rates of both the vegetation and of the livestock are demonstrated to be highly influential. Rests during wet years are crucial for the regeneration of the pasture. We conclude that even though a non-equilibrium rangeland system is assumed, the application of pure opportunistic strategies – destocking in times of drought and fast post-drought restocking – are not always adequate to maintain the long-term productivity of the pasture. Rest periods are indispensable when vegetation has a low regeneration potential. On an applied level, the study emphasises that improved farming conditions (supplementary feeding, unrestricted options to purchase livestock) may run the risk of ecological as well as economic damages.     

Chukar Watering Patterns and Water Site Selection

We evaluated chukar (Alectoris chukar) watering patterns as well as habitat variables influencing water site selection in western Utah. Motion-sensing cameras and chukar dropping counts were primary techniques to evaluate watering patterns. We took vegetative and other habitat measurements at each water source (n = 43) to discriminate use from nonuse sites using logistic regression. Chukars watered during daylight hours with a modal hour from 1200 hours to 1300 hours daylight savings time. Annual patterns suggest limited use of water sources from November to May with first observed visits occurring in June and last observed visits in October. Shrub canopy cover was the only variable to discriminate between site types (P &spilt; 0.01). Cross validation showed a predictive success rate of 84%. Significant differences were found between use and nonuse sites in terms of security cover (P &spilt; 0.01), but not total cover (P &spigt; 0.05). Chukars seem to have a loose shrub canopy threshold near 11% that is likely due to predation risk. Water sources meeting this threshold received use, whereas those not meeting this threshold did not. Increasing shrub canopy cover above 11% did not translate into increased water source use. Managers might want to consider annual patterns when setting hunt season timing and structure as well as judging sites for new water developments based on shrub canopy cover. More generally, these results suggest a behavioral constraint on the use of water sources as a function of predation risk—we should expect other species to demonstrate similar behavioral constraints. These constraints must be considered in any effort to determine benefits or impacts of water developments.     

Participatory design of farm level adaptation to climate risks in an arable region in The Netherlands

In the arable farming region Flevoland in The Netherlands climate change, including extreme events and pests and diseases, will likely pose risks to a variety of crops including high value crops such as seed potato, ware potato and seed onion. A well designed adaptation strategy at the farm level can reduce risks for farmers in Flevoland. Currently, most of the impact assessments rely heavily on (modelling) techniques that cannot take into account extreme events and pests and diseases and cannot address all crops, and are thus not suited as input for a comprehensive adaptation strategy at the farm level.To identify major climate risks and impacts and develop an adaptation measure portfolio for the most relevant risks we complemented crop growth modelling with a semi-quantitative and participatory approach, the Agro Climatic Calendar (ACC), A cost-benefit analysis and stakeholder workshops were used to identify robust adaptation measures and design an adaptation strategy for contrasting scenarios in 2050.For Flevoland, potential yields of main crops were projected to increase, but five main climate risks were identified, and these are likely to offset the positive impacts. Optimized adaptation strategies differ per scenario (frequency of occurrence of climate risks) and per farm (difference in economic loss). When impacts are high (in the +2 °C and A1 SRES scenario) drip irrigation was identified as the best adaptation measure against the main climate risk heat wave that causes second-growth in seed and ware potato. When impacts are smaller (the +1 °C and B2 SRES scenario), other options including no adaptation are more cost-effective.Our study shows that with relatively simple techniques such as the ACC combined with a stakeholder process, adaptation strategies can be designed for whole farming systems. Important benefits of this approach compared to modelling techniques are that all crops can be included, all climate factors can be addressed, and a large range of adaptation measures can be explored. This enhances that the identified adaptation strategies are recognizable and relevant for stakeholders.     

Economic trade-offs to limit nonpoint sources of agricultural pollution

A national model has been built which allows analysis of physical and economic trade-offs as soil loss per acre is limited to specified levels in each major land group of the nation. Crop variables with their associated conservation practices are developed for each of 1891 land groups in 223 agricultural producing regions and 51 water supply regions. The regions and soil groups are made interdependent through regional commodity demands and a transportation submodel. Hence, changes in cropping systems and erosion control practices in one region are simultaneously expressed in effects on other regions. Soil loss limits are set at 10, 5, and 3 t per acre. The 10 t limit does not have a large impact on interregional production patterns and farm comodity prices. However, the 5 and 3 t limits, either singularly or in combination with different export levels, cause rather marked increases in commodity prices. Also at limits of 5 and 3 t, considerable shifts take place among regions in the crops grown and the erosion control methods used. Regions with erosive soils sacrificed in reduced income; regions with level soils can crop more intensely and gain greater income. Conservation practices such as reduced tillage increase the amount of pesticides needed in some regions and pose special environmental problems. The South Atlantic region is affected most by soil loss limits to control nonpoint pollution. The Great Plains regions with more level land and limited rainfall are affected least.     

Subsurface drainage performance study using SALTMOD and ANN models

Relative performance of artificial neural networks (ANNs) and the conceptual model SALTMOD was studied in simulating subsurface drainage effluent and root zone soil salinity in the coastal rice fields of Andhra Pradesh, India. Three ANN models viz. Back Propagation Neural Network (BPNN), General Regression Neural Network (GRNN) and Radial Basis Function Neural Network (RBFNN) were developed for this purpose. Both the ANNs and the SALTMOD were calibrated and validated using the field data of 1998–2001 for 35 and 55 m drain spacing areas. Data on irrigation depth, evapotranspiration, drain discharges, water table depths, mean monthly rainfall and temperature and drainage effluent salinity were used for ANN model training, testing and validation. It was observed that the BPNN model with feed forward learning rule with 6 processing elements in input layer and 1 hidden layer with 12 processing elements performed better than the other ANN models in predicting the root zone soil salinity and drainage effluent salinity. Considering coefficient of determination, model efficiency and variation between the observed and predicted salinity values as the evaluation parameters, the SALTMOD performed better in predicting root zone soil salinity and the BPNN performed better in predicting the drainage effluent salinity. Therefore, it was concluded that the BPNN with feed forward learning algorithm was a better model than SALTMOD in predicting salinity of drainage effluent from salt affected subsurface drained rice fields.     

Necrophylactic periderm formation in the roots of western larch and Douglas‐fir trees infected with Armillaria ostoyae. II. The response to the pathogen

Periderm formation was studied in bark samples collected from the roots of western larch (Larix occidentalis) and Douglas‐fir (Pseudotsuga menziesii) trees infected with Armillaria ostoyae. Necrophylactic periderms were formed in advance of infection and successfully restricted continued fungal spread in 68 and 45% of the samples collected from 10‐ and 27‐year‐old western larch, respectively. However, all periderms formed in 11‐ and 25‐year‐old Douglas‐fir had been breached by the advancing fungus. In both species, necrophylactic periderms were commonly breached at the junction of the periderm with the vascular cambium. In western larch, stone phellem often comprised the external phellem layer of necrophylactic periderms with multiple bands of phellem. In 27‐year‐old western larch, infection was often confined to discrete lesions bounded by multiple periderms with multiple bands of phellem. In both tree species, phellem production was greater in response to infection than in response to abiotic wounding.     

市级土地利用总体规划实施评估研究--以湖南省邵阳市为例

指出了第三轮土地利用总体规划目前已实施7年,随着新情况、新形势的出现,规划也出现了一些不适应性。探讨了土地利用总体规划实施监测评估体系的构建,并提出了相关建议,对规划的继续实施以及对新一轮规划的修编均能提供一定的参考依据。     

Assessment of cable tensile forces in active winch-assist harvesting using an anchor machine configuration

European Journal of Forest Research - The growing interest in accessing steep terrain is pushing the expansion of the operating range of ground-based machines through winch-assist technology....