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31.
Katharina Schulz Maike Guschal Ingo Kowarik Jarcilene S. Almeida-Cortez Everardo V. S. B. Sampaio Arne Cierjacks 《Regional Environmental Change》2018,18(7):1969-1981
Grazing is the main land use in semi-arid regions of the world, and sustainable management practices are urgently needed to prevent their degradation. However, how different grazing intensities affect forest density and ecosystem functions is often not sufficiently understood to allow for management adaptations that safeguard the ecosystems and their functions in the long run. We assessed the aboveground carbon stocks and plant densities along a grazing gradient in the semi-arid seasonally dry tropical forest of north-eastern Brazil (Caatinga). On 45 study plots, we analysed the aboveground carbon stocks of the vegetation and determined forest density and recruitment as well as the population structure of the most abundant tree species. Grazing intensity was accounted for based on the weight of livestock droppings and classified as low, intermediate, or high. Mean aboveground carbon stock was 15.74?±?1.92 Mg ha?1 with trees and shrubs accounting for 89% of the total amount. Grazing at high intensities significantly reduced aboveground carbon stocks of herbs but not of other plant functional types. Instead, aboveground carbon stocks of trees and shrubs were negatively related to altitude above sea level, which is a proxy for reduced water availability along with lower anthropogenic impact. The population structure of the most common tree species was characterised by abundant recruitment, irrespective of grazing, whereas the recruitment of less frequent woody species was negatively affected by grazing. Overall, our data imply that grazing and forage management need to be adapted, including the reduction of free-roaming livestock and storage of fodder, to maintain carbon storage and forest density. 相似文献
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Past on-site experience was linked to the crowding perceptions and use displacement of 383 on-site visitors to the peri-urban
Danube Floodplains National Park, Austria. Three visitor groups were determined according to their area experience: local
residents from Vienna and rural communities, having the highest level of experience; regional visitors from the city and eastern
Austria; and tourists from Austria and abroad with the lowest degree of experience. Crowding perceptions were significantly
different across the user groups. More than 50% of local residents perceived the national park as crowded, whereas only 27%
of regional visitors and 19% of tourists reported such an evaluation. Even among local residents and regional visitors, respondents
with more on-site experience expressed a greater impression of a crowded park. Differences in crowding evaluations between
local rural and urban residents and between regional rural and urban visitors were not found. For 27% of local residents and
15% of regional visitors, use levels were so unacceptable that they displaced temporally and spatially, whereas use displacement
was relatively irrelevant for tourists. The use displacement strategies involved differ among the three user groups. Management
implications were discussed, taking the specific situation of the small national park on the urban-rural fringe into consideration. 相似文献
35.
Kupper Priit Rohula Gristin Inno Liina Ostonen Ivika Sellin Arne Sõber Anu 《Regional Environmental Change》2017,17(7):2149-2157
Regional Environmental Change - At northern latitudes, a rise in atmospheric humidity and precipitation is predicted as a consequence of global climate change. We investigated the impact of high... 相似文献
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Edvard Lidén Arne Ulander Fuat Deniz Anita Gidöf Gunnarsson Steven Nordin Lennart Högman 《Environment international》1997,23(6):93
The present field study addressed the need for a procedure that provides a defined unit of measurement of perceived annoyance from environmental odors, calibrating the estimates for individual scaling behavior and context effects. In including 25 subjects, the purpose was to demonstrate the applicability of the master-scale procedure with magnitude estimation to perform such a calibration of odor-annoyance estimates for target stimuli such as road-traffic combustion exhausts (13 000 vehicles/d; averaging 47 μg/m3 over the day/night with peaks exceeding 100 μg/m3 of nitrogen dioxide; NO2). For comparison, calibrated estimates were also obtained for a backyard expected to be considerably less polluted (comparable with 18 μg/m3 of NO2) and for blank stimuli presented indoors. The data transformation for the calibration procedure with which annoyance is expressed in either master-scale units or pyridine equivalents requires estimates of a reference stimulus for which seven concentrations of pyridine were used. The results provide an illustration of master scaling of odor annoyance, and imply that use of a modulus (standard stimulus with a predefined annoyance magnitude), in contrast to master scaling, is not sufficient for calibration for individual scaling behavior and context effects. 相似文献
37.
Marianna Siegmund-Schultze Maria do Carmo Sobral Márcia M. G. Alcoforado de Moraes Jarcilene S. Almeida-Cortez J. Roberto G. Azevedo Ana Lúcia Candeias Arne Cierjacks Edvânia T. A. Gomes Günter Gunkel Volkmar Hartje Fred F. Hattermann Martin Kaupenjohann Hagen Koch Johann Köppel 《Regional Environmental Change》2018,18(7):1883-1888
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The case described in this article regards 4.7 km of beach in Ferring, situated approx. 5 km south to the mouth of the Limfjord
strait on the west coast of Denmark. In 2005, this section of the beach was nourished with 721,000 m3 of material in order to protect backshore properties, natural heritages and the recreational value of the beach. After the
nourishment, the beach was monitored by levelling profiles on four dates to monitor and track the evolution of the nourished
material. Furthermore, laboratory tests involving different gradations of nourishment material are shown which indicate solutions
to different kinds of coastal protection strategies, estimate the time in between two nourishments and evaluate the cost of
maintaining a beach with a high recreational value for the public. 相似文献
40.
Climate change is expected to influence spatial and temporal distributions of fish stocks. The aim of this paper is to compare climate change impact on a fishery with other factors impacting the performance of fishing fleets. The fishery in question is the Northeast Arctic cod fishery, a well-documented fishery where data on spatial and temporal distributions are available. A cellular automata model is developed for the purpose of mimicking possible distributional patterns and different management alternatives are studied under varying assumptions on the fleets’ fishing aptitude. Fisheries management and fishing aptitude, also including technological development and local knowledge, turn out to have the greatest impact on the spatial distribution of the fishing effort, when comparing the IPCC’s SRES A1B scenario with repeated sequences of the current environmental situation over a period of 45 years. In both cases, the highest profits in the simulation period of 45 years are obtained at low exploitation levels and moderate fishing aptitude. 相似文献