Using geomorphological variables to predict the spatial distribution of plant species in agricultural drainage networks

Two-stage channels can enhance local biodiversity in agricultural landscapes

Field drainage causes habitat loss, alters natural flow regimes, and impairs water quality. Still, drainage ditches often are last remnants of aquatic and wetland habitats in agricultural landscapes and as such, can be important for local biodiversity. Two-stage channels are considered as a greener choice for conventional ditches, as they are constructed to mimic the structure of natural lowland streams providing a channel for drainage water and mechanisms to decrease diffuse loading. Two-stage channels could also benefit local biodiversity and ecosystem functions, but existing information on their ecological benefits is scarce and incomplete. We collected environmental and biological data from six agricultural stream systems in Finland each with consequent sections of a conventional ditch and a two-stage channel to study the potential of two-stage channels to enhance aquatic and riparian biodiversity and ecological functions. Biological data included samples of stream invertebrates, diatoms and plants and riparian beetles and plants. Overall, both section types were highly dominated by few core taxa for most of the studied organism groups. Riparian plant and invertebrate communities seemed to benefit from the two-stage channel structure with adjacent floodplains and drier ditch banks. In addition, two-stage channel sections had higher aquatic plant diversity, algal productivity, and decomposition rate, but lower stream invertebrate and diatom diversity. Two-stage channel construction did not diversify the structure of stream channels which is likely one explanation for the lack of positive effects on benthic diversity. However, both section types harbored unique taxa found only in one of the two types in all studied organism groups resulting in higher local gamma diversity. Thus, two-stage channels enhanced local biodiversity in agricultural landscapes. Improvements especially in aquatic biodiversity might be achieved by increasing the heterogeneity of in-stream habitat structure and with further efforts to decrease nutrient and sediment loads.

Application of ArcGIS 3D modeling technology in the study of land use policy decision making in China

In this paper, a land use management information system based on ArcGIS 3D modeling technology is constructed to process land use policy decisions through ArcSDE spatial data engine and Oracle relational database to realize a land use planning management information system. Using genetic algorithm in order to use for regional land use optimization allocation, the introduction of multi-intelligent body system in this algorithm will be able to enhance the optimization search ability of the algorithm and make the genetic algorithm to obtain land use planning supported. The behavior of the main body of the integrated land use planning decision maker will guide the development of the quantitative structure of land use in terms of spatial layout toward sustainability. The experimental results prove that the target is better than the other three types of scenarios under the integrated benefit model, then it is reduced by 18.67%, 15.98% and 16.61%, and the number of spatially contiguous areas is increased by 9.4%, 13.8% and 0.8%, respectively. The proposed model can reasonably configure the regional land use quantitative results and spatial layout, and coordinate the needs of different land use decision makers.