Land Use Data (land + use_data)

Distribution by Scientific Domains

Selected Abstracts

Prediction and validation of the potential global distribution of a problematic alien invasive species , the American bullfrog

Gentile Francesco Ficetola
ABSTRACT Predicting the probability of successful establishment and invasion of alien species at global scale, by matching climatic and land use data, is a priority for the risk assessment. Both large- and local-scale factors contribute to the outcome of invasions, and should be integrated to improve the predictions. At global scale, we used climatic and land use layers to evaluate the habitat suitability for the American bullfrog Rana catesbeiana, a major invasive species that is among the causes of amphibian decline. Environmental models were built by using Maxent, a machine learning method. Then, we integrated global data with information on richness of native communities and hunting pressure collected at the local scale. Global-scale data allowed us to delineate the areas with the highest suitability for this species. Predicted suitability was significantly related to the invasiveness observed for bullfrog populations historically introduced in Europe, but did not explain a large portion of variability in invasion success. The integration of data at the global and local scales greatly improved the performance of models, and explained > 57% of the variance in introduction success: bullfrogs were more invasive in areas with high suitability and low hunting pressure over frogs. Our study identified the climatic factors entailing the risk of invasion by bullfrogs, and stresses the importance of the integration of biotic and abiotic data collected at different spatial scales, to evaluate the areas where monitoring and management efforts need to be focused. [source]

Assessment of European streams with diatoms, macrophytes, macroinvertebrates and fish: a comparative metric-based analysis of organism response to stress

Summary 1. Periphytic diatoms, macrophytes, benthic macroinvertebrates and fish were sampled with standard methods in 185 streams in nine European countries to compare their response to degradation. Streams were classified into two main stream type groups (i.e. lowland, mountain streams); in addition, the lowland streams were grouped into four more specific stream types. 2. Principal components analysis with altogether 43 environmental parameters was used to construct complex stressor gradients for physical,chemical, hydromorphological and land use data. About 30 metrics were calculated for each sample and organism group. Metric responses to different stress types were analysed by Spearman Rank Correlation. 3. All four organism groups showed significant response to eutrophication/organic pollution gradients. Generally, diatom metrics were most strongly correlated to eutrophication gradients (85% and 89% of the diatom metrics tested correlated significantly in mountain and lowland streams, respectively), followed by invertebrate metrics (91% and 59%). 4. Responses of the four organism groups to other gradients were less strong; all organism groups responded to varying degrees to land use changes, hydromorphological degradation on the microhabitat scale and general degradation gradients, while the response to hydromorphological gradients on the reach scale was mainly limited to benthic macroinvertebrates (50% and 44% of the metrics tested correlated significantly in mountain and lowland streams, respectively) and fish (29% and 47%). 5. Fish and macrophyte metrics generally showed a poor response to degradation gradients in mountain streams and a strong response in lowland streams. 6. General recommendations on European bioassessment of streams were derived from the results. [source]

The assessment of surface water resources for the semi-arid Yongding River Basin from 1956 to 2000 and the impact of land use change

Lei Wang
Abstract The assessment of surface water resources (SWRs) in the semi-arid Yongding River Basin is vital as the basin has been in a continuous state of serious water shortage over the last 20 years. In this study, the first version of the geomorphology-based hydrological model (GBHM) has been applied to the basin over a long period of time (1956,2000) as part of an SWR assessment. This was done by simulating the natural hydrological processes in the basin. The model was first evaluated at 18 stream gauges during the period from 1990 to 1992 to evaluate both the daily streamflows and the annual SWRs using the land use data for 1990. The model was further validated in 2000 with the annual SWRs at seven major stream gauges. Second, the verified model was used in a 45-year simulation to estimate the annual SWRs for the basin from 1956 to 2000 using the 1990 land use data. An empirical correlation between the annual precipitation and the annual SWRs was developed for the basin. Spatial distribution of the long-term mean runoff coefficients for all 177 sub-basins was also achieved. Third, an additional 10-year (1991,2000) simulation was performed with the 2000 land use data to investigate the impact of land use changes from 1990 to 2000 on the long-term annual SWRs. The results suggest that the 10-year land use changes have led to a decrease of 83 107 m3 (79% of total) for the 10-year mean annual SWRs in the simulation. To our knowledge, this work is the first attempt to assess the long-term SWRs and the impact of land use change in the semi-arid Yongding River Basin using a semi-distributed hillslope hydrological model. Copyright 2010 John Wiley & Sons, Ltd. [source]

Specification issues in models of population and employment growth*

Marlon G. Boarnet
Spatial econometrics; population and employment growth Abstract., This article examines two specification issues common to spatial econometric population-employment growth models: the specification of the weight matrix and the dynamic stability implied by estimated lag parameters. Using data on Orange County census tracts from 1980 to 1990, we estimate a simultaneous system of regressions for tract population and employment growth. Six different weight matrices are tested, ranging from simple contiguity matrices to more complex matrices based on commute flows between census tracts. We also examine whether the inclusion of detailed information on land use improves performance of the lagged adjustment model. The results provide insights for future applications of econometric population-employment growth models. We found that the estimated lag parameters were consistent with dynamic stability for the models that included detailed land use data. Results varied for different weight matrices, but variation was mostly confined to interaction between population and employment growth. [source]