共查询到10条相似文献，搜索用时 62 毫秒
1.
Christine E. Pribulick Lauren M. Foster Lindsay A. Bearup Alexis K. Navarre‐Sitchler Kenneth H. Williams Rosemary W.H. Carroll Reed M. Maxwell 《Ecohydrology》2016,9(8):1431-1438
Land cover change due to drought and insect‐induced tree mortality or altered vegetation succession is one of the many consequences of anthropogenic climate change. While the hydrologic response to land cover change and increases in temperature have been explored independently, few studies have compared these two impacts in a systematic manner. These changes are particularly important in snow‐dominated, headwaters systems that provide streamflow for continental river systems. Here we study the hydrologic impacts of both vegetation change and climate warming along three transects in a mountain headwaters watershed using an integrated hydrologic model. Results show that while impacts due to warming generally outweigh those resulting from vegetation change, the inherent variability within the transects provides varying degrees of response. The combination of both vegetation change and warming results in greater changes to streamflow amount and timing than either impact individually, indicating a nonlinear response from these systems to multiple perturbations. The complexity of response underscores the need to integrate observational data and the challenge of deciphering hydrologic impacts from proxy studies. 相似文献
2.
Ana Filipa Filipe Danijela Markovic Florian Pletterbauer Clément Tisseuil Aaike De Wever Stefan Schmutz Núria Bonada Jörg Freyhof 《Diversity & distributions》2013,19(8):1059-1071
Aim
Species inhabiting fresh waters are severely affected by climate change and other anthropogenic stressors. Effective management and conservation plans require advances in the accuracy and reliability of species distribution forecasts. Here, we forecast distribution shifts of Salmo trutta based on environmental predictors and examine the effect of using different statistical techniques and varying geographical extents on the performance and extrapolation of the models obtained.Location
Watercourses of Ebro, Elbe and Danube river basins (c. 1,041,000 km2; Mediterranean and temperate climates, Europe).Methods
The occurrence of S. trutta and variables of climate, land cover and stream topography were assigned to stream reaches. Data obtained were used to build correlative species distribution models (SDMs) and forecasts for future decades (2020s, 2050s and 2080s) under the A1b emissions scenario, using four statistical techniques (generalised linear models, generalised additive models, random forest, and multivariate adaptive regression).Results
The SDMs showed an excellent performance. Climate was a better predictor than stream topography, while land cover characteristics were not necessary to improve performance. Forecasts predict the distribution of S. trutta to become increasingly restricted over time. The geographical extent of data had a weak impact on model performance and gain/loss values, but better species response curves were generated using data from all three basins collectively. By 2080, 64% of the stream reaches sampled will be unsuitable habitats for S. trutta, with Elbe basin being the most affected, and virtually no new habitats will be gained in any basin.Main conclusions
More reliable predictions are obtained when the geographical data used for modelling approximate the environmental range where the species is present. Future research incorporating both correlative and mechanistic approaches may increase robustness and accuracy of predictions.3.
4.
Pioneer Taashwa Gamundani Kudzai Mpakairi Christopher Magadza Shakkie Kativu Elmon Dhlomo 《African Journal of Ecology》2020,58(3):432-445
Climate models project a hot and dry future for Southern Africa. In this research, Maximum Entropy was used to model the extent to which climate change, land cover and distance from water edges may influence current and future distribution of the African skimmer in the mid-Zambezi Valley. Global Biodiversity Information Facility data collected between the years 2000–2019 were used to develop the models. Three models were built: one for current distribution and two for future distribution under Representative Concentration Pathways (RCPs) 2.6 and 6.0. Results revealed that annual precipitation and distance from water edges were the most important predictors of habitat suitability for the African skimmer under current and future climate. Temperature and land cover were least important in explaining current and future distribution of the species. The RCP 2.6 predicted future decrease in suitable habitat for the African skimmer in the mid-Zambezi Valley, while RCP 6.0 predicted future increase in suitable habitat for the species. This research conclusively revealed that precipitation and distance from water edges were consistently key predictors of suitable habitat for the African skimmer. 相似文献
5.
Jürgen Kusch 《Insect Conservation and Diversity》2015,8(1):92-101
- Effects of various climatic factors, altitude and land cover types on the distribution of eight caddisfly species were modelled from occurrence data by the use of the maximum entropy method. The predicted habitat use and the most contributing environmental factors differed considerably among species. Those differences of responses may be a basis for changes of assemblage structures with climate changes.
- Precipitation in late spring to early summer, minimum temperatures in the second half of the year, and temperature seasonality, or other bioclimatic factors that give information about the temporal stability of temperatures (‘diurnal range’, ‘isothermality’), were key climate factors influencing the distribution of most of the studied species. Therefore, climate change may affect Trichoptera assemblages not only by the height of mean temperatures but also by temperature variability.
- Land cover types contributed to the development of distribution models for several caddisfly species. Forests promoted most of the species, whereas cultivated and managed areas were less preferred. Few species concentrated on individual land cover types, e.g. Wormalida occipitalis on coniferous forest. Therefore, different adaptations of caddisfly species to land cover types, in addition to climatic factors, seam to occur, and are discussed to facilitate niche partitioning.
- Environmental variables that were observed to affect the distribution of caddisflies, i.e. temperature, precipitation, and vegetation, may interact with each other. Climate changes may influence caddisflies not only via temperature changes, but by related changes of precipitation regimes, and by a long‐term change of vegetation types, e.g. tree species predominant in forests.
6.
地表反照率是影响地表辐射收支与能量平衡的重要地表物理参数,是区域和全球气候变化研究中的一个关键要素。以三江源为案例区,基于2001—2018年生长季(6—8月)中分辨率成像光谱仪(MODIS)地表反照率(MCD43C3)产品,以及同期气候和植被指数数据,应用随机森林回归算法量化植被和气候对地表反照率时空变化的影响分析了土地利用/覆被变化导致的地表辐射特性参数(地表反照率)的改变引起的辐射温度效应。结果表明：三江源区域生长季地表反照率在空间上呈自东南向西北递增的特征,其均值为(0.163±0.027),集中分布在0.12—0.18。长江源园区、黄河源园区以及澜沧江源园区地表反照率差异较大,分别是(0.177±0.036)、(0.153±0.037)和(0.156±0.002)。从年际变化来看,研究区地表反照率以每10年(0.152±0.763)%速率不显著下降(P=0.47),但其变化趋势存在明显空间分异,其中显著减少(增加)的区域占8.4%(1.9%),长江源园区、黄河源园区以及澜沧江源园区以不同速率下降,分别为每10年下降(0.078±0.900)%、(0.215±0.740)%、(... 相似文献
7.
Regression Techniques for Examining Land Use/Cover Change: A Case Study of a Mediterranean Landscape 总被引：4，自引：0，他引：4
In many areas of the northern Mediterranean Basin the abundance of forest and scrubland vegetation is increasing, commensurate
with decreases in agricultural land use(s). Much of the land use/cover change (LUCC) in this region is associated with the
marginalization of traditional agricultural practices due to ongoing socioeconomic shifts and subsequent ecological change.
Regression-based models of LUCC have two purposes: (i) to aid explanation of the processes driving change and/or (ii) spatial
projection of the changes themselves. The independent variables contained in the single ‘best’ regression model (that is,
that which minimizes variation in the dependent variable) cannot be inferred as providing the strongest causal relationship with the dependent variable. Here, we examine the utility of hierarchical partitioning and multinomial regression
models for, respectively, explanation and prediction of LUCC in EU Special Protection Area 56, ‘Encinares del río Alberche
y Cofio’ (SPA 56) near Madrid, Spain. Hierarchical partitioning estimates the contribution of regression model variables,
both independently and in conjunction with other variables in a model, to the total variance explained by that model and is
a tool to isolate important causal variables. By using hierarchical partitioning we find that the combined effects of factors
driving land cover transitions varies with land cover classification, with a coarser classification reducing explained variance
in LUCC. We use multinomial logistic regression models solely for projecting change, finding that accuracies of maps produced
vary by land cover classification and are influenced by differing spatial resolutions of socioeconomic and biophysical data.
When examining LUCC in human-dominated landscapes such as those of the Mediterranean Basin, the availability and analysis
of spatial data at scales that match causal processes is vital to the performance of the statistical modelling techniques
used here. 相似文献
8.
《植物生态学报》1958,44(5):543
随着人口的增长和人类社会的发展, 土地利用与土地覆盖变化已经是不可避免。土地利用与土地覆盖变化不仅对生态系统的要素、结构和功能产生深远的影响, 也会对全球变化产生反馈作用。针对土地利用与土地覆盖变化的过程、驱动机制以及在各个方面可能产生的生态环境效应的科学研究已经全面开展。该文综述了土地利用与土地覆盖变化对气候、土壤、生物地球化学循环、生物多样性以及区域生态环境等影响方面的研究进展, 并提出了相关研究的前沿方向展望。随着新技术的不断发展, 学者们将更多地侧重预测未来全球变化背景下的土地利用与土地覆盖变化趋势、合理性以及适应性, 为可持续发展提供基础资料和理论依据。 相似文献
9.
随着人口的增长和人类社会的发展, 土地利用与土地覆盖变化已经是不可避免。土地利用与土地覆盖变化不仅对生态系统的要素、结构和功能产生深远的影响, 也会对全球变化产生反馈作用。针对土地利用与土地覆盖变化的过程、驱动机制以及在各个方面可能产生的生态环境效应的科学研究已经全面开展。该文综述了土地利用与土地覆盖变化对气候、土壤、生物地球化学循环、生物多样性以及区域生态环境等影响方面的研究进展, 并提出了相关研究的前沿方向展望。随着新技术的不断发展, 学者们将更多地侧重预测未来全球变化背景下的土地利用与土地覆盖变化趋势、合理性以及适应性, 为可持续发展提供基础资料和理论依据。 相似文献
10.
近几十年中国地区土地利用/覆盖变化(LUCC)较大,在区域气候模拟中尤其需要使用更加准确的土地利用/覆盖数据。基于模式原有的USGS和新开发的LUC90两种土地利用/覆盖资料,利用区域环境集成模拟系统(RIEMS2.0)分别进行连续10a模拟,分析LUCC对中国不同季节气温的影响。结果表明:1)采用LUC90资料后,中国及东北、华北、华南夏季平均气温增加,但只有东北模拟与观测值的偏差减小,且通过显著性检验(P0.01)。中国及东北、华南冬季平均气温增加,并且模拟与观测值的偏差减少。中国及华北和华南对冬季气温年际变率的模拟改善好于夏季。2)土地利用/覆盖变化通过影响潜热通量的变化和净吸收辐射通量的变化来影响不同季节气温的变化。冬季净辐射通量变化对气温变化的贡献较夏季大,而夏季潜热通量变化对气温变化的贡献较冬季大。雨养农田转变森林、草地、灌溉农田过程造成通量变化,其对气温变化的影响也存在不同分区季节的差异。 相似文献