土地利用变化对鸟类栖息地连通性的影响——以鄂州市为例

土地利用变化是造成栖息地破碎、缺失与退化的重要原因。生态网络能保护重要栖息地,促进栖息地之间的物质与能量流动,对区域土地利用规划和生物多样性保护具有重要意义。以鄂州市为研究区,基于CLUE-S模型预测现状延续、生态保护和城市扩张3种土地利用情景,将生境质量作为遴选生境斑块的依据之一,以鸟类最大迁徙距离为阈值构建生态网络,从连通概率指数PC和斑块重要性指数dPC两方面,探讨土地利用变化对鸟类栖息地连通性的影响。结果表明：(1)不同情景的地类数量和空间结构均有差异,与生态保护相比,城市扩张情景的建设用地增加11603.52 hm~2,林地、耕地和水体减少5041.8 hm~2、2540.16 hm~2、3385.8 hm~2,新城区、山地风景区与水体周边是主要变化区域;(2)现状延续和城市扩张情景的生境斑块降至235块和216块,网络出现破碎化,生态保护情景增至367块,网络结构完整但空间位置改变;(3)2004—2024年PC表现为先上升后下降再上升的趋势,生态保护的PC高于现状延续和城市扩张,且利于保护短距离迁徙鸟类;(4)生态保护情景边缘型和关键小型斑块得到保护,第一等级斑块增加,城...     

Population and Land Use Effects on Malaria Prevalence in the Southern Brazilian Amazon

Malaria prevalence has been one of the most dramatic outcomes of the occupation of the Brazilian Amazon as exemplified by Northern Mato Grosso, one of the areas of highest malaria prevalence in the Americas in the early 1990s. This paper associates the dynamicsof high malaria prevalence in Northern Mato Grosso with three land uses—small-scalegold mining (garimpos), agricultural colonization/cattle ranching (rural), and urban activities—and their related population characteristics, which constitute riskprofiles. Furthermore, spatial proximity and population mobility between (a) garimpos and new rural settlements and (b) older rural settlements or urban areas are key factors explaining malaria diffusion throughout the region. The paper identifies and characterizes populations at high malaria risk and the effects of land use types on malaria diffusion, providing policymakers with information for regional and local policies to control malaria and minimize its effects on Amazonian populations.     

Impact of land use on the ecology of uncultivated plant species in the Rwenzori mountain range,mid western Uganda

Rwenzori mountain range is important for its high diversity of unique species and as a water catchment area and yet very fragile to human interference. The study documented the impact of land use on ecology of uncultivated plant species in the Rwenzori mountain range using Bugoye sub‐county as a reference site. The ecological aspects of the plants studied included distribution, abundance and diversity of the plant species in and around the various land uses as well as in degraded, disturbed and undisturbed areas. Land uses identified were; agriculture, built up area and land with other activities (conservation and abandoned fields). The study revealed that agriculture was the main land use category taking up 69.7% of land use area. Plants distributed in and around the land uses were mainly trees with species diversity of 34.5%. Generally, there was no relationship in the distribution of plant species in degraded, undisturbed and disturbed areas (a = 0.01). In disturbed areas, there was vegetation cover especially of plant species that occur as secondary re‐growth, and in degraded areas, the ground was sparsely covered by primary succession species while in the undisturbed areas, plant species growing in a ‘natural. habitat dominated and most of them were climax species.     

Land‐use change outweighs projected effects of changing rainfall on tree cover in sub‐Saharan Africa

Global change will likely affect savanna and forest structure and distributions, with implications for diversity within both biomes. Few studies have examined the impacts of both expected precipitation and land use changes on vegetation structure in the future, despite their likely severity. Here, we modeled tree cover in sub‐Saharan Africa, as a proxy for vegetation structure and land cover change, using climatic, edaphic, and anthropic data (R² = 0.97). Projected tree cover for the year 2070, simulated using scenarios that include climate and land use projections, generally decreased, both in forest and savanna, although the directionality of changes varied locally. The main driver of tree cover changes was land use change; the effects of precipitation change were minor by comparison. Interestingly, carbon emissions mitigation via increasing biofuels production resulted in decreases in tree cover, more severe than scenarios with more intense precipitation change, especially within savannas. Evaluation of tree cover change against protected area extent at the WWF Ecoregion scale suggested areas of high biodiversity and ecosystem services concern. Those forests most vulnerable to large decreases in tree cover were also highly protected, potentially buffering the effects of global change. Meanwhile, savannas, especially where they immediately bordered forests (e.g. West and Central Africa), were characterized by a dearth of protected areas, making them highly vulnerable. Savanna must become an explicit policy priority in the face of climate and land use change if conservation and livelihoods are to remain viable into the next century.     

Assessing the impact of land use and climate change on the evergreen broad-leaved species of <Emphasis Type="Italic">Quercus acuta</Emphasis> in Japan

To assess the impact of Quercus acuta, a dominant species in the evergreen broad-leaved forests of Japan, and its habitat shifts as a result of climate change, we predicted the potential habitats under the current climate and two climate change scenarios using a random forest (RF). The presence/absence records of Q. acuta were extracted from the Phytosociological Relevè Data Base as response variables, and four climatic variables (warmth index, WI; minimum temperature of the coldest month, TMC; summer precipitation, PRS; and winter precipitation, PRW) were used as predictor variables. The mean decrease in the Gini criterion revealed that WI was the most influential factor followed by TMC. The RF revealed a considerable increase in potential habitats (PHs) under the climate change scenarios for 2081–2100 (RCM20, 180,141 km²; MIROC, 175,635 km²) relative to the current climate (150,542 km²). The land use variables were used for masking PH. The PH masked by land use (PHLU) was approximately half of the PH under the current conditions (74,567 km²). Under the climate change scenarios and 1 km migration options, the PHLU were not increased relative to its value under the current conditions. The distribution of Q. acuta was restricted by the northward shift in northern Honshu, but expanded as a result of the upward shift into the mountain areas of Western Japan. Habitat fragmentation reduced the ability of migration to respond to climate change in the lowland areas of Japan.     

气候与土地利用变化下宁夏清水河流域径流模拟

气候和土地利用变化是影响水资源变化最直接的因素。应用SWAT模型对干旱半干旱区小流域宁夏清水河流域径流进行多情景模拟预测,以历史气候要素变化趋势和CA-Markov模型分别设置未来气候和土地利用变化情景,以决定系数R2和Nash-Sutcliffe模型效率系数Ens(Nash-Sutcliffe efficiency coefficient)来衡量模拟值与实测值之间的拟合度,并评价模型在清水河流域的适用性。结果表明,韩府湾站在校准期和验证期的R~2分别为0.80和0.71,Ens分别为0.77和0.69,泉眼山站在校准期和验证期的R2分别为0.66和0.63,Ens分别为0.62和0.56,表明构建的SWAT模型可以用于清水河流域的径流模拟。对未来气候和土地利用变化情景下径流的模拟结果显示,径流变化主要由降水变化主导,降水减少和气温升高的综合作用对流域径流变化影响最为显著;由于耕地和建设用地的增加,未来3种土地利用情景下流域径流量将均会呈现明显增加变化。与2010年相比,到2020年,自然增长情景流域径流将增加17.04%,林地保护情景径流将增加14.44%,规划情景径流将增加13.98%;综合降水、气温和土地利用的结合变化情景显示,未来流域径流将会有不同程度的下降,规划情景和气候变化的结合情景的径流下降最为明显,而有意增大林地和加强生态保护的林地保护情景对减缓流域径流下降具有一定作用。在气候变化的大背景下,根据水资源利用管理目标,可通过调整流域管理措施,特别是土地利用变化和改善区域小气候来减缓气候变化对流域水资源的负面效果,以此来改善流域径流和生态环境状况。     

High-resolution distribution of bumblebees (Bombus spp.) in a mountain area marked by agricultural decline

Since the 1980s, bumblebee species have declined in Europe, partly because of agricultural intensification. Yet little is known about the potential consequences of agricultural decline on bumblebees. In most mountainous areas, agricultural decline from rural exodus is acute and alters landscapes as much as intensive farming. Our study aims at providing a quantitative assessment of agricultural decline through its impact on landscapes, and at characterising bumblebee assemblages associated with land-use types of mountain regions. The studied area (6.2 km²) belongs to the Eyne’s valley in the French Pyrenees, known to host the exceptional number of 33 bumblebee species of the 45 found in continental France. We compare aerial photographs from 1953 and 2000 to quantify agricultural decline. We cross a bumblebee database (2849 observations) with land-use types interpreted from aerial photographs from 2000. Comparison of land-use maps from 1953 and 2000 reveals a strong progression of woodland and urbanised areas, and a decline of agricultural land (pastures and crops), except for hayfields. Spatial correlations between low altitude agro-pastoral structure and the occurrence of bumblebee species shows that bumblebee specific richness is highest in agro-pastoral land-uses (pastures and hayfields) and in the ski area, and poorest in woodland and urbanised areas. Urbanisation and agricultural decline, through increased woodland areas, could lead to a loss of bumblebee diversity in the future. To preserve high bumblebee richness, it is crucial to design measures to maintain open land habitats and the landscape’s spatial heterogeneity through agro-pastoral practices.     

西安市城乡建设用地时空扩展及驱动因素

城乡建设用地变化及驱动机制是国内外研究的热点领域,我国正处在城镇化快速发展时期,建设用地的迅速扩张已成为当前中国土地利用变化的主要特征。以5期(1975、1990、2000、2005和2010年)土地利用现状数据为基础,利用GIS空间分析技术,提取建设用地变化及空间分布信息,利用建设用地扩展指数和建设用地密度分析方法对近35年来(1975—2010年)西安市建设用地扩展的时空特征进行分析。并结合社会经济数据,对建设用地空间扩展驱动力进行分析。结果表明:西安市建设用地面积急剧增长,建筑密度不断加大,并且城乡空间差异较大。西安市建设用地扩展是多因素综合作用的结果,高程和坡度控制着建设用地的分布格局,城市沿河谷扩展。西安市城市建设应加强区域宏观规划和土地利用详细规划,切实保护秦岭北麓林草地,加强历史文化名城特色,避免低层次文化复古创修。     

Carbon sequestration potential in European croplands has been overestimated

Yearly, per‐area carbon sequestration rates are used to estimate mitigation potentials by comparing types and areas of land management in 1990 and 2000 and projected to 2010, for the European Union (EU)‐15 and for four country‐level case studies for which data are available: UK, Sweden, Belgium and Finland. Because cropland area is decreasing in these countries (except for Belgium), and in most European countries there are no incentives in place to encourage soil carbon sequestration, carbon sequestration between 1990 and 2000 was small or negative in the EU‐15 and all case study countries. Belgium has a slightly higher estimate for carbon sequestration than the other countries examined. This is at odds with previous reports of decreasing soil organic carbon stocks in Flanders. For all countries except Belgium, carbon sequestration is predicted to be negligible or negative by 2010, based on extrapolated trends, and is small even in Belgium. The only trend in agriculture that may be enhancing carbon stocks on croplands at present is organic farming, and the magnitude of this effect is highly uncertain. Previous studies have focused on the potential for carbon sequestration and have shown quite significant potential. This study, which examines the sequestration likely to occur by 2010, suggests that the potential will not be realized. Without incentives for carbon sequestration in the future, cropland carbon sequestration under Article 3.4 of the Kyoto Protocol will not be an option in EU‐15.     

Recent land‐use changes affect stream ecosystem processes in a subtropical island in Brazil

Land‐use changes such as conversion of natural forest to rural and urban areas have been considered as main drivers of ecosystem functions decline, and a large variety of indicators has been used to investigate these effects. Here, we used a replicated litter‐bag experiment to investigate the effects of land‐use changes on the leaf‐litter breakdown process and leaf‐associated invertebrates along the forest–pasture–urban gradient located in a subtropical island (Florianópolis, SC, Brazil). We identified the invertebrates and measured the litter breakdown rates using the litter bags approach. Litter bags containing 3 g of dry leaf of Alchornea triplinervia were deployed on forest rural and urban streams. Principal component analysis, based on physico‐chemical variables which, confirmed a gradient of degradation from forest to urban streams with intermediate values in rural areas. In accordance, shredder richness and abundance were lower in rural and urban than in forest streams. The land‐use changes led also to the dominance of tolerant generalist taxa (Chironomidae and Oligochaeta) reducing the taxonomic and functional diversity in these sites. Leaf‐litter breakdown rates decreased from forest to rural and finally to urban areas and were associated with changes in pH, water velocity, dissolved oxygen and abundance of leaf‐shredding invertebrates, although global decomposition rates did not differ between rural and urban streams. Overall, this study showed that land‐use changes, namely to rural and urban areas, have a strong impact on tropical streams ecosystems, in both processes and communities composition and structure. Despite of being apparently a smaller transformation of landscape, rural land use is comparable to urbanisation in terms of impact in stream functioning. It is thus critical to carefully plan urban development and maintain forest areas in the island of Florianópolis in order to preserve its natural biodiversity and aquatic ecosystems functioning.     

基于“源地-廊道”生态安全格局构建逻辑范式的建设用地减量化研究

建设用地急剧扩张导致土地利用覆被发生剧烈变化,物种栖息地丧失、破碎化及分离,严重威胁到社会经济及生态可持续发展。以快速城市化地区苏锡常为研究区域、地区优势物种白鹭生境为源地、"源地-廊道"生态安全格局构建逻辑范式为重要性评价依据,识别并筛选出对维护、控制目标物种生态过程具有重要意义的、可增强地区生境整体性及连通性的网络构成要素及其缓冲区,对缓冲区内建设用地进行减量化,提出一套建设用地减量化系统性方法。结果表明：（1）研究区内重要生态"源地"及"对应廊道"内建设用地需减量化10170.44 hm²,其中城镇用地5408.38 hm²,农村居民点4107.96 hm²,交通用地654.10 hm²。（2）依据生态安全格局构建逻辑范式,增补保护不同类型"源地"及"对应廊道",可在提升区域生态安全水平的同时,识别出新的需要减量化的建设用地。该方法也可作为区域内存量及增量建设用地空间布局调整优化的依据,具有较好的普适性。     

The impact of land use and land cover change on biodiversity within and adjacent to Kibasira Swamp in Kilombero Valley,Tanzania

Wetlands are crucial ecosystems with multiple values and functions to a range of different stakeholders. The future of wetlands depends both on the legacy of the past and how they are currently used. Using 48 vegetation survey plots (0.08 ha) combined with Landsat 5 and 7 TM imagery, we assessed the influence of long‐term (1990–2011) land use and land cover change on the biodiversity of the Kibasira Swamp. Information on perceptions of adjacent communities on historical changes and drivers for the changes were also collected. Results showed an increase in the area covered by open water by 1% and forest by 4% between 1990 and 1998 whilst Cyperus papyrus L and cultivated land area decreased by 8% and 3%, respectively on the same period. Between 1998 and 2011, there was a decrease in areas covered by water by 35% and forest by 9% whereas C. papyrus L increased by 40% and cultivated land increased by 8%. These changes have affected the biodiversity of the swamp and adjacent to it as numbers of mammals have declined. However, the Swamp still provides extensive habitat for plants and bird species despite the ongoing human pressure. Interventions may be necessary to maintain biodiversity in Kibasira Swamp to ensure sustainable ecosystem services.     

轻中度石漠化地区不同土地利用类型叶蝉群落结构及动态

轻中度石漠化地区生态环境较为脆弱,昆虫是生态系统中的重要角色。以叶蝉作为指示生物,在轻中度石漠化地区选取刺梨林、核桃林、玫瑰园、桃林、李子林以及草地6种不同土地利用类型的样地进行叶蝉标本采集,分析6类样地中叶蝉群落的物种组成、相似性、多样性、均匀度和丰富度等特征及其与各地理要素之间的关系。同时还分析了不同月份叶蝉群落的物种组成、多样性、均匀度和丰富度等指数的变化趋势。结果如下：共鉴定叶蝉11亚科52属。拟竹叶蝉属Bambusananus Li&Xing、顶斑叶蝉属Empoascanara Distant和小绿叶蝉属Empoasca Walsh是各样地的优势类群,共占69.4%。尤其是小绿叶蝉属Empoasca,在不同样地中个体数都是最多,占总采集数量的44.6%。Shannon-Wiener多样性指数表现为：刺梨林 > 草地 > 核桃林 > 李子林 > 桃树林 > 玫瑰园;Pieluo均匀性指数则是：草地 > 刺梨林 > 李子林 > 桃树林 > 核桃林 > 玫瑰园,Simpson优势度指数为：玫瑰园 > 李子林 > 草地 > 刺梨林 > 桃树林 > 核桃林。温度是影响叶蝉群落个体数量的重要环境因子之一,气压和湿度等环境因子则与之无明显相关性。结果表明在生态环境脆弱的轻中度石漠化地区,草地和刺梨林两种土地利用类型的叶蝉个体数与类群数较为丰富,是较为合适的喀斯特生态环境修复的土地利用类型,研究结果将对石漠化治理和喀斯特轻-中度石漠化地区生态恢复技术集成与示范具有重要指导意义。     

土地利用/覆被变化对生物栖息地连接度的影响——以巩义地区黄鼬、蒙古兔和黄喉貂为例

土地利用/覆被变化通过改变生物栖息地而对物种分布产生影响。以河南省巩义市为研究区域,选取分布在该区域的哺乳动物黄鼬(Mustela sibirica)、蒙古兔(Lepus tolai)和黄喉貂(Martes flavigula)为目标物种,首先依据其生物特性和生态需求,确定了这3个物种的扩散能力;其次,基于景观连接度原理,分析了1990—2011年研究区土地利用整体变化和各类型变化情况,及其对单一物种和多物种栖息地连接度变化的影响。研究结果表明:(1)土地利用整体变化使得栖息地连接度增加,变化范围为22.22%—45.46%;(2)各土地利用类型变化对栖息地连接度的影响差异显著,连接度的升高和降低与栖息地斑块面积增加和减少密切相关;(3)基于多目标物种栖息地整体连接度空间分布图,确定了研究区目标物种保护的关键区域。     

Land suitability for energy crops under scenarios of climate change and land‐use

Bioenergy is expected to play a critical role in climate change mitigation. Most integrated assessment models assume an expansion of agricultural land for cultivation of energy crops. This study examines the suitability of land for growing a range of energy crops on areas that are not required for food production, accounting for climate change impacts and conservation requirements. A global fuzzy logic model is employed to ascertain the suitable cropping areas for a number of sugar, starch and oil crops, energy grasses and short rotation tree species that could be grown specifically for energy. Two climate change scenarios are modelled (RCP2.6 and RCP8.5), along with two scenarios representing the land which cannot be used for energy crops due to forest and biodiversity conservation, food agriculture and urban areas. Results indicate that 40% of the global area currently suitable for energy crops overlaps with food land and 31% overlaps with forested or protected areas, highlighting hotspots of potential land competition risks. Approximately 18.8 million km² is suitable for energy crops, to some degree, and does not overlap with protected, forested, urban or food agricultural land. Under the climate change scenario RCP8.5, this increases to 19.6 million km² by the end of the century. Broadly, climate change is projected to decrease suitable areas in southern regions and increase them in northern regions, most notably for grass crops in Russia and China, indicating that potential production areas will shift northwards which could potentially affect domestic use and trade of biomass significantly. The majority of the land which becomes suitable is in current grasslands and is just marginally or moderately suitable. This study therefore highlights the vital importance of further studies examining the carbon and ecosystem balance of this potential land‐use change, energy crop yields in sub‐optimal soil and climatic conditions and potential impacts on livelihoods.     

Forecasting the combined effects of future climate and land use change on the suitable habitat of Davidia involucrata Baill

Accurately predicting the future distribution of species is crucial for understanding how species will response to global environmental change and for evaluating the effectiveness of current protected areas (PAs). Here, we assessed the effect of climate and land use change on the projected suitable habitats of Davidia involucrata Baill under different future scenarios using the following two types of models: (a) only climate covariates (climate SDMs) and (b) climate and land use covariates (full SDMs). We found that full SDMs perform significantly better than climate SDMs in terms of both AUC (p < .001) and TSS (p < .001) and also projected more suitable habitat than climate SDMs both in the whole study area and in its current suitable range, although D. involucrate is predicted to loss at least 26.96% of its suitable area under all future scenarios. Similarly, we found that these range contractions projected by climate SDMs would negate the effectiveness of current PAs to a greater extent relative to full SDMs. These results suggest that although D. involucrate is extremely vulnerability to future climate change, conservation intervention to manage habitat may be an effective option to offset some of the negative effects of a changing climate on D. involucrate and can improve the effectiveness of current PAs. Overall, this study highlights the necessity of integrating climate and land use change to project the future distribution of species.     

Land cover dynamics of different topographic conditions in Beijing, China

Topographic conditions play an important role in controlling land cover dynamic processes. In this study, remotely sensed data and the geographic information system were applied to analyze the changes in land cover along topographic gradients from 1978 to 2001 in Beijing, a rapidly urbanized mega city in China. The study was based on five periods of land cover maps derived from remotely sensed data: Landsat MSS for 1978, Landsat TM for 1984, 1992, 1996 and 2001, and the digital elevation model (DEM) derived from 1:250,000 topographic map. The whole area was divided into ten land cover types: conifer forest, broadleaf forest, mixed forest, shrub, brushwood, meadow, farmland, built-up, water body and bare land. The results are summarized as follows. (1) Shrub, forest, farmland and builtup consist of the main land cover types of the Beijing area. The most significant land cover change from 1978 to 2001 was the decrease of the farmland and expansion of the builtup area. Farmland decreased from 6354 to 3813 km2 in the 23 years, while the built-up area increased from 421 to 2642 km2. Meanwhile, the coverage of forest increased from 17.2% to 24.7% of the total area. The conversion matrix analysis indicated that the transformation of farmland to the built-up area was the most significant process and afforestation was the primary cause of the replacement of shrub to forest. (2) Topographic conditions are of great importance to the distribution of land cover types and the process of land cover changes. Elevation has an intensive impact on the distribution of land cover types. The area below 100 m mostly consists of farmland and built-up areas, while the area above 100 m is mainly covered by shrub and forest. Shrub has the maximum frequency in areas between 100 and 1000 m, while forest has dominance in areas above 800 m. According to the analysis of land cover changes in different ranges of elevation, the greatest change below 100 m was the process of urbanization. The process of the main land cover change occurred above 100 m was the transformation from shrub to forest. This result was consistent with the vertical change of natural vegetation distribution in Beijing. (3) Slope has a great influence on the distribution of land cover. Farmland and built-up areas are mostly distributed in flat areas, while shrub and forest occupy steeper areas compared with other land cover types. Forest frequency increased with the increasing slope. Land cover changes differed from the slope gradients. In the plain area, the land cover change occurred as the result of urbanization. With the increasing of the slope gradient, afforestation, which converts shrub to forest, was the process of the primary land cover change. __________ Translated from Journal of Plant Ecology, 2006, 30(2): 239–251 [译自: 植物生态学报]     

Potential carbon sequestration of European arable soils estimated by modelling a comprehensive set of management practices

Bottom–up estimates from long‐term field experiments and modelling are the most commonly used approaches to estimate the carbon (C) sequestration potential of the agricultural sector. However, when data are required at European level, important margins of uncertainty still exist due to the representativeness of local data at large scale or different assumptions and information utilized for running models. In this context, a pan‐European (EU + Serbia, Bosnia and Herzegovina, Montenegro, Albania, Former Yugoslav Republic of Macedonia and Norway) simulation platform with high spatial resolution and harmonized data sets was developed to provide consistent scenarios in support of possible carbon sequestration policies. Using the CENTURY agroecosystem model, six alternative management practices (AMP) scenarios were assessed as alternatives to the business as usual situation (BAU). These consisted of the conversion of arable land to grassland (and vice versa), straw incorporation, reduced tillage, straw incorporation combined with reduced tillage, ley cropping system and cover crops. The conversion into grassland showed the highest soil organic carbon (SOC) sequestration rates, ranging between 0.4 and 0.8 t C ha^?1 yr^?1, while the opposite extreme scenario (100% of grassland conversion into arable) gave cumulated losses of up to 2 Gt of C by 2100. Among the other practices, ley cropping systems and cover crops gave better performances than straw incorporation and reduced tillage. The allocation of 12 to 28% of the European arable land to different AMP combinations resulted in a potential SOC sequestration of 101–336 Mt CO₂ eq. by 2020 and 549‐2141 Mt CO₂ eq. by 2100. Modelled carbon sequestration rates compared with values from an ad hoc meta‐analysis confirmed the robustness of these estimates.     

雷州半岛红树林鱼类群落结构及其与人类活动强度的关系

水产养殖、城镇建设等引起的土地利用变化使红树林生态系统遭受严重破坏,是红树林生物多样性面临的主要威胁之一。了解雷州半岛红树林鱼类群落结构,探究人类活动强度对鱼类群落结构的影响,对红树林鱼类资源保护至关重要。基于2021—2022年雷州半岛7片红树林共21条潮沟的鱼类数据,结合周边土地利用数据,研究鱼类群落结构及其与土地利用类型的关系。结果显示,共采集鉴定鱼类49种,隶属于8目25科,鲈形目鱼类最多,共33种占总种类数的75.5%,其中,虾虎鱼科种数最多,共15种占30.6%;食性上,主要为杂食性和肉食性鱼类,分别为53.06%和44.90%;各红树林Shannon-Wiener多样性指数在秋冬春三季的变化范围均为0—2.5,Simpson多样性指数均为0—0.9;各红树林鱼类个体数、物种数和生物量均存在显著差异(P>0.05);除秋季北潭与流沙湾的鱼类群落无显著差异(P>0.05)外,其余红树林间的鱼类群落在三个季度均有显著差异(P<0.05);人类活动强度、红树林面积和东西岸对鱼类多样性指数、个体数、物种数和生物量均有显著的主效应和交互效应(P<0.05);青...     

低碳导向下土地覆被演变模拟——以深圳市为例

全球碳排放水平的不断增加引起的全球变暖越发严重,导致了严重的自然灾害和经济损失,这种失衡发展的态势促使着各个国家开始探索低碳环保的发展模式。为了探究何种土地利用组成可以更好的为低碳城市服务,以深圳市为研究区,结合2020年土地利用现状结构和2020年土地利用规划结构分别估算出碳汇最大化情景和碳排放量最小化情景下2020年各土地利用类型的数量结构,并运用FLUS模型模拟出深圳市土地利用类型在这两种情景下的空间分布特征。最后,从碳密度和碳排放视角对比这两种情景的低碳效益。研究结果如下：①碳汇最大化和碳排放最小化情景下土地利用总碳盈余均比2020年少,且碳汇最大化情景下土地利用总碳盈余最小。碳汇最大化情景下耕地、园地和林地面积增加而水域和建设用地减少,碳排放最小化情景下园地和林地面积增加来源于草地、水域和建设用地的减少,这两种低碳情景的碳汇能力增强而碳排放量减少;②碳汇最大化和碳排放最小化情景下林地明显增加故而土地利用总碳盈余均比实际情景小,而园地和草地的缩减和扩张是引起两种低碳情景碳密度和碳排放量有差异的主要原因。碳汇最大化和碳排放最小化情景下,西部和东南部主要是碳密度增加和碳排放减少的区域,而中部是碳密度减少和碳排放增加的区域。因此对中部区域进行重点调控,有利于深圳市碳中和和碳达峰的实现。研究可以为深圳的低碳发展提供规划建议,同时给其他区域的低碳规划提供参考意见。