Over the last few years, the impacts of wildlife on agriculture have constantly been growing, in particular in areas close to woodland and in hunting ban zones (“refuge effect”). Public administrations have difficulty in meeting the growing requests for crop damage compensation. The development of appropriate measures to control this trend—starting from the understanding of the dynamics concerned—is crucial. The aim of this study was, therefore, to analyze damage at regional scale and define common local actions. In particular, the study involved different steps that define a spatial-based classification of risk levels, integrating statistical methods (principal component analysis and receiver operating characteristic) with multi-criteria evaluation (MCE) in a geographic information system (GIS). It turns out that, in the study area, the very high-risk zones affect 8.83% of used agricultural areas; about 97% of them concentrated in the first 400 m from the most suitable habitats. A selected cluster of 11 test areas within these zones allowed us to assess the cost-effectiveness of integrated prevention and control actions (IPCA) with respect to the compensation of the damage. The analysis shows cost of IPCA to be nearly twice the actual cost incurred by the public administration to compensate partially the damage. The comparison with the estimated damage shows the overall economic convenience of the proposed investment with significant differences depending on the areas. Thus, we suggest reaching an “agro-ecological” balance starting from actions on specific areas; if they produce the desired effects, they could be progressively extended to other areas with gradual investments (adaptive management).
The variability of rainfall-dependent streamflow at catchment scale modulates many ecosystem processes in wet temperate forests. Runoff in small mountain catchments is characterized by a quick response to rainfall pulses which affects biogeochemical fluxes to all downstream systems. In wet-temperate climates, water erosion is the most important natural factor driving downstream soil and nutrient losses from upland ecosystems. Most hydrochemical studies have focused on water flux measurements at hourly scales, along with weekly or monthly samples for water chemistry. Here, we assessed how water and element flows from broad-leaved, evergreen forested catchments in southwestern South America, are influenced by different successional stages, quantifying runoff, sediment transport and nutrient fluxes during hourly rainfall events of different intensities. Hydrograph comparisons among different successional stages indicated that forested catchments differed in their responses to high intensity rainfall, with greater runoff in areas covered by secondary forests (SF), compared to old-growth forest cover (OG) and dense scrub vegetation (CH). Further, throughfall water was greatly nutrient enriched for all forest types. Suspended sediment loads varied between successional stages. SF catchments exported 455 kg of sediments per ha, followed by OG with 91 kg/ha and CH with 14 kg/ha, corresponding to 11 rainfall events measured from December 2013 to April 2014. Total nitrogen (TN) and phosphorus (TP) concentrations in stream water also varied with rainfall intensity. In seven rainfall events sampled during the study period, CH catchments exported less nutrients (46 kg/ha TN and 7 kg/ha TP) than SF catchments (718 kg/ha TN and 107 kg/ha TP), while OG catchments exported intermediate sediment loads (201 kg/ha TN and 23 kg/ha TP). Further, we found significant effects of successional stage attributes (vegetation structure and soil physical properties) and catchment morphometry on runoff and sediment concentrations, and greater nutrients retention in OG and CH catchments. We conclude that in these southern hemisphere, broad-leaved evergreen temperate forests, hydrological processes are driven by multiple interacting phenomena, including climate, vegetation, soils, topography, and disturbance history. 相似文献
We analyze the magnetic configurations of three super active regions, NOAA 10484, 10486 and 10488, observed by the Huairou Multi-Channel Solar Telescope (MCST) from 2003 October 18 to November 4. Many energetic phenomena, such as flares (including a X-28 flare) and coronal mass ejections (CMEs), occurred during this period. We think that strong shear and fast emergence of magnetic flux are the main causes of these events. The question is also of great interest why these dramatic eruptions occurred so close together in the descending phase of the solar cycle. 相似文献
Charge-coupled device (CCD) photometry in the Johnson V , Kron–Cousins I and Washington CMT 1 systems is presented in the field of the poorly known open cluster NGC 2627. Four independent Washington abundance indices yield a mean cluster metallicity of [Fe/H]=−0.12 ± 0.08 , which is compatible with the existence of a radial gradient in the Galactic disc. The resultant colour–magnitude diagrams indicate that the cluster is an intermediate-age object of 1.4 Gyr. Based on the best fits of the Geneva group's isochrones to the ( V , V − I ) and ( T 1, C − T 1) diagrams, we estimate E ( V − I ) = 0.25 ± 0.05 and V − MV = 11.80 ± 0.25 for log t = 9.15 , and E ( C − T 1) = 0.23 ± 0.07 and T 1− M T 1= 11.85 ± 0.25 for log t = 9.10 , respectively, assuming solar metal content. The derived reddening value E ( C − T 1) implies E ( B − V ) = 0.12 ± 0.07 and a distance from the Sun of 2.0 ± 0.4 kpc . Using the WEBDA data base and the available literature, we re-examined the overall properties of all the open clusters with ages between 0.6 and 2.5 Gyr. We identified peaks of cluster formation at 0.7–0.8, 1.0–1.1, 1.6–1.7 and 2.0–2.1 Gyr, separated by relative quiescent epochs of ∼0.2–0.3 Gyr. We also estimated a radial abundance gradient of −0.08 ± 0.02 , which is consistent with the most recent determinations for the Galactic disc, but no clear evidence for a gradient perpendicular to the Galactic plane is found. 相似文献
