Human impact on the landscape of small islands in the West-Estonian archipelago

Research on the development of the interrelationship between society and environment is crucial for the understanding of contemporary landscapes. The West-Estonian archipelago provides an opportunity for such investigations because of its small size, landscape diversity, and well-defined economic activities. The contemporary landscapes of the islands reflect environmental changes resulting from centuries of human activity. This paper describes both natural and human factors in the change in landscape of small Estonian islands during the last centuries. During the period 1850–1940, human activity diversified the landscape structure. During World War II, with the establishment of Soviet rule, the islets were depopulated; their landscape became more uniform and lost their economic and ecological vitality. The re-establishment of private ownership of land and a market economy is predicted to result in positive changes in the landscape of the islets.     

Human impact on the landscape of small islands in the West-Estonian archipelago

Research on the development of the interrelationships between society and environment is crucial for the understanding of contemporary landscapes. The West-Estonian archipelago provides an opportunity for such investigations because of its small size, landscape diversity, and well-defined economic activities. The contemporary landscapes of the islands reflect environmental changes resulting from centuries of human activity. This paper describes both natural and human factors in the change in landscape of small Estonian islands during the last centuries. During the period 1850–1940, human activity diversified the landscape structure. During World War II, with the establishment of Soviet rule, the islets were depopulated; their landscape became more uniform and lost their economic and ecological vitality. The re-establishment of private ownership of land and a market economy is predicted to result in positive changes in the landscape of the islets.     

A Multispecies Framework for Landscape Conservation Planning

Abstract: Rapidly changing landscapes have spurred the need for quantitative methods for conservation assessment and planning that encompass large spatial extents. We devised and tested a multispecies framework for conservation planning to complement single‐species assessments and ecosystem‐level approaches. Our framework consisted of 4 elements: sampling to effectively estimate population parameters, measuring how human activity affects landscapes at multiple scales, analyzing the relation between landscape characteristics and individual species occurrences, and evaluating and comparing the responses of multiple species to landscape modification. We applied the approach to a community of terrestrial birds across 25,000 km² with a range of intensities of human development. Human modification of land cover, road density, and other elements of the landscape, measured at multiple spatial extents, had large effects on occupancy of the 67 species studied. Forest composition within 1 km of points had a strong effect on occupancy of many species and a range of negative, intermediate, and positive associations. Road density within 1 km of points, percent evergreen forest within 300 m, and distance from patch edge were also strongly associated with occupancy for many species. We used the occupancy results to group species into 11 guilds that shared patterns of association with landscape characteristics. Our multispecies approach to conservation planning allowed us to quantify the trade‐offs of different scenarios of land‐cover change in terms of species occupancy.     

Road development, housing growth, and landscape fragmentation in northern Wisconsin: 1937-1999.

Roads remove habitat, alter adjacent areas, and interrupt and redirect ecological flows. They subdivide wildlife populations, foster invasive species spread, change the hydrologic network, and increase human use of adjacent areas. At broad scales, these impacts cumulate and define landscape patterns. The goal of this study was to improve our understanding of the dynamics of road networks over time, and their effects on landscape patterns, and identify significant relationships between road changes and other land-use changes. We mapped roads from aerial photographs from five dates between 1937 and 1999 in 17 townships in predominantly forested landscapes in northern Wisconsin, U.S.A. Patch-level landscape metrics were calculated on terrestrial area outside of a 15-m road-effect zone. We used generalized least-squares regression models to relate changes in road density and landscape pattern to concurrent changes in housing density. Rates of change and relationships were compared among three ecological regions. Our results showed substantial increases in both road density and landscape fragmentation during the study period. Road density more than doubled, and median, mean, and largest patch size were reduced by a factor of four, while patch shape became more regular. Increases in road density varied significantly among ecological subsections and were positively related to increases in housing density. Fragmentation was largely driven by increases in road density, but housing density had a significantly positive relationship with largest patch area and patch shape. Without protection of roadless areas, our results suggest road development is likely to continue in the future, even in areas where road construction is constrained by the physical environment. Recognizing the dynamic nature of road networks is important for understanding and predicting their ecological impacts over time and understanding where other types of development are likely to occur in the future. Historical perspectives of development can provide guidance in prioritizing management efforts to defragment landscapes and mitigate the ecological impacts of past road development.     

东北北部温带森林和干草地土壤养分分布及影响因素

土壤是陆地生态系统碳储存的重要场所,其养分变化与全球陆地碳循环密切相关。土壤养分是植物生长的重要保证,而土壤各养分之间是紧密联系的。理解土壤养分变化与环境因素的关系有助于更好地了解陆地生态系统碳、氮、磷循环。本研究以东北北部自东向西沿降水量梯度变化纬度带上的温带森林与干草地生态系统为研究对象,利用气象数据和野外土壤实测数据,分析了纬度带上不同植被类型土壤的有机碳、全氮、碳氮比、速效磷的空间分布格局及其与环境因子（年降水量、年均温、土壤pH值）的关系。研究纬度带上降水量自东向西逐渐减少,植被类型从温带森林过渡到干草原,与降水量和植被类型对应,植被生物量也自东向西呈现从高到低的分布梯度。研究结果表明：从整个研究带上来说,降水量与土壤pH值是土壤养分空间分布的决定因素,沿纬度带从东到西,随着降水量逐渐减少,土壤pH值逐渐增加,而土壤有机碳、全氮、碳氮比、速效磷含量逐渐减少。但如果将森林和草地分别讨论则发现,森林和草地生态系统的土壤养分环境控制因素有较大差别。对于草地生态系统而言,降水量和土壤pH值仍然是其土壤养分含量的控制因子,但森林生态系统由于所处区域降水量充足,降水量不再是其土壤养分的控制因子,降水量只与森林土壤碳氮比呈显著正相关。研究还发现森林土壤的速效磷含量与温度呈正相关,与土壤pH值呈负相关,说明温度对东北北部温带森林的土壤养分含量具有一定的控制作用。     

武夷山风景名胜区景观要素斑块特征分析

针对近年来开展生态旅游等人类活动的强烈干扰给风景区带来巨大生态影响的问题，在武夷山风景名胜区景观类型划分的基础上，从景观要素斑块特征的角度对武夷山风景名胜区的景观格局及破碎化进行初步的研究，以期为今后武夷山风景名胜区的景观生态保护提供科学的依据．研究结果表明，在武夷山风景名胜区中，马尾松林、茶园与农田是风景区中3个主要景观类型，三者面积与周长之和分别占全区的84．581％和81．669％；景观要素的面积、周长、斑块数的分布极不平衡，尤其在3类主要景观类型中，在斑块面积、周长方面差异显著；各景观要素面积与周长的分布极为相似，而斑块数的分布却没有明显的规律性；景观要素面积、周长、斑块数等斑块特征分析表明，茶园、居住地、经济林等人工或半人工经营景观的破碎化程度高，而马尾松各天然林景观的破碎化程度低，从而证明了人类经营活动的干扰是导致自然风景区景观破碎的主要因素之一．表3参18     

云南临沧地区公路两侧紫茎泽兰分布格局

云南省临沧地区是我国紫茎泽兰(Eupatorium adenophorum)传入最早和入侵危害最严重的地区。文章在该地区选取典型路段并设置了10个样地,以等级、路宽、路面状况、路龄、人类活动干扰不同的7条公路为研究对象,分析了紫茎泽兰生物量、株高和株数与距公路距离、公路宽度、景观类型、坡向及海拔的关系。结果表明,公路对紫茎泽兰生物量和株高有显著影响的最远距离为24m,而对株数的影响达34m;6m宽的公路对紫茎泽兰生物量和株数影响最显著,且路龄越长、交通干扰越大的公路两侧的紫茎泽兰入侵危害越严重;紫茎泽兰在公路附近的撂荒地和次生林两个景观类型中入侵危害严重,景观类型对生物量与坡向对株高的影响不显著,位于南坡公路附近的紫茎泽兰生物量和株数最高,研究发现公路附近紫茎泽兰总生物量随海拔升高而增加,在1700m达最大,随后则降低。     

典范相关分析在桉树人工林地土壤酶活性与营养元素关系研究中的应用

运用典范相关分析（canonical correlation analysis)对桉树人工林地土壤酶活性和土壤营养元素含量关系的研究表明,土壤过氧化氢酶,脲酶和蛋白酶活性与土壤营养元素N,P,K含量关系最大,其中地氧化氢酶与桉树土壤K听转化,K的固定关系密切,对土壤中主要营养物质N素的转化具有重要作用,脲酶的活性同桉树土壤N,P的转化关系密切,蛋白酶促进土壤对植物氮源的供给,而转化酶与P的转化也有一定相关,Zn在一定程度上对转化酶有正效庆,即有促进作用。结合林地生物的生长特征等因子,“综合土壤酶因子”可作为土壤肥力评价的一个生物学指标。图2表4参16     

Interactive effects of natural and human disturbances on vegetation dynamics across landscapes.

Accurate measures of human effects on landscape processes require consideration of both the direct impacts from human activities and the indirect consequences of the interactions between humans and the landscape. This is particularly evident in systems experiencing regular natural disturbances such as in the mountainous areas of southwestern China, where the remaining population of giant pandas (Ailuropoda melanoleuca) is supported. Here the spatiotemporal patterns of human impacts, forests, and bamboo episodic die-offs combine to determine the distribution of panda habitat. To study the complex interactions of humans and landscapes, we developed an integrated spatiotemporally explicit model of household activities, natural vegetation dynamics, and their impacts on panda habitat. Using this model we examined the direct consequences of local fuelwood collection and household creation on areas of critical giant panda habitat and the indirect impacts when coupled with vegetation dynamics. Through simulations, we found that over the next 30 years household impacts would result in the loss of up to 30% of the habitat relied on by pandas during past bamboo die-offs. The accumulation and spatial distribution of household impacts would also have a considerable indirect influence on the spatial distribution of understory bamboo. While human impacts influence both bamboo die-off and regeneration, over 19% of pre-existing low-elevation bamboo habitat may be lost following an episodic die-off depending on the severity of the impacts and timing of the die-offs. Our study showed not only the importance of the spatial distribution of direct household impacts on habitat, but also the far-reaching effects of the indirect interactions between humans and the landscapes they are modifying.     

基于水土流失的景观格局分析方法

景观格局和生态过程是景观生态学研究的重要内容,但是很多研究只重视景观格局的研究,而忽略了生态过程的研究。文章针对水土流失这一重要生态过程,提出了基于水土流失过程的景观坡度指数和景观空间负荷对比指数,并对黄土高原泾河流域15个子流域的景观格局进行了分析,认为泾河流北部各子流域主要以水土流失的＂源＂景观为主,景观坡度指数大,空间负荷指数小,水土流失风险大;流域南部各子流域上游以＂汇＂景观为主,坡度指数大,中下游以＂源＂景观为主,景观空间分布不均衡,存在一定的水土流失风险;流域东部局部子流域主要以水土流失的＂汇＂景观为主,＂源＂景观相对较小,＂源＂-＂汇＂景观空间分布均衡,水土流失风险小。     

Influence of Landscape Elements in Riparian Buffers on the Conservation of Semiaquatic Amphibians

Abstract:  Studies on riparian buffers have usually focused on the amount of land needed as habitat for the terrestrial life stages of semiaquatic species. Nevertheless, the landscape surrounding wetlands is also important for other key processes, such as dispersal and the dynamics of metapopulations. Multiple elements that influence these processes should therefore be considered in the delineation of buffers. We analyzed landscape elements (forest cover, density of roads, and hydrographic network) in concentric buffers to evaluate the scale at which they influence stream amphibians in 77 distinct landscapes. To evaluate whether our results could be generalized to other contexts, we determined whether they were consistent across the study areas. Amphibians required buffers of 100–400 m of suitable terrestrial habitat, but interspecific differences in the amount of habitat were large. The presence of amphibians was related to roads and the hydrographic network at larger spatial scales (300–1500 m), which suggests that wider buffers are needed with these elements. This pattern probably arose because these elements influence dispersal and metapopulation persistence, processes that occur at large spatial scales. Furthermore, in some cases, analyses performed on different sets of landscapes provided different results, which suggests caution should be used when conservation recommendations are applied to disparate areas. Establishment of riparian buffers should not be focused only on riparian habitat, but should take a landscape perspective because semiaquatic species use multiple elements for different functions. This approach can be complex because different landscape elements require different spatial extents. Nevertheless, a shift of attention toward the management of different elements at multiple spatial scales is necessary for the long-term persistence of populations.     

Reconnaissance soil geochemical survey of Gibraltar

The extreme density of population of Gibraltar, situated at the southern tip of Spain, exerts considerable pressure on land use and thus future planning is of utmost importance. An initial reconnaissance soil geochemical survey of Gibraltar was based on 120 surface samples (0–15 cm) taken from a wide range of exposed, either bare soil or vegetated sites, to provide the optimum geographical distribution. The total elemental concentrations of 26 elements (Li, Na, K, Be, Mg, Ca, Sr, Ba, Al, La, Ti, V, Cr, Mo, Mn, Fe, Co, Ni, Cu, Ag, Zn, Cd, Pb, P, S, As) were determined by nitric/percholric acid digestion followed by inductively coupled plasma-atomic emission spectrometry (ICP-AES) analysis. The reconnaissance data shows that the spatial distribution of various elements depended on previous and present land use. Most elements (Ca, Cr, Mg and Mn excluded) exhibited relatively high concentrations in civilian and natural soils. Trends have been established for many elements, and concentrations exceeding guideline values have been found in certain areas of Gibraltar. This reconnaissance of Gibraltar is at present being followed by a more detailed baseline geochemical survey, which will establish the extent and magnitude of the variations in major and trace elements in soils and dusts, assess the impact of industrial, commercial and urban development on the geochemical landscape and to make recommendations concerning sustainable development.     

Birds in agricultural mosaics: the influence of landscape pattern and countryside heterogeneity.

Agricultural environments are critical to the conservation of biota throughout the world. Efforts to identify key influences on the conservation status of fauna in such environments have taken complementary approaches. Many studies have focused on the role of remnant or seminatural vegetation and emphasized the influence on biota of spatial patterns in the landscape. Others have recognized that many species use diverse "countryside" elements within farmland, and emphasize the benefits of landscape heterogeneity for conservation. Here, we investigated the effect of independent measures of both the spatial pattern (extent and configuration) and heterogeneity of elements (i.e., land uses/vegetation types) on bird occurrence in farm-scale agricultural mosaics in southeastern Australia. Birds were sampled in all types of elements in 27 mosaics (each 1 x 1 km) selected to incorporate variation in cover of native vegetation and the number of different element types in the mosaic. We used an information-theoretic approach to identify the mosaic properties that most strongly influenced bird species richness. Subgroups of birds based on habitat requirements responded most strongly to the extent of preferred elements in mosaics. Woodland birds were richer in mosaics with higher cover of native vegetation while open-tolerant species responded to the extent of scattered trees. In contrast, for total species richness, mosaic heterogeneity (richness of element types) and landscape context (cover of native vegetation in surrounding area) had the greatest influence. These results showed that up to 76% of landscape-level variation in richness of bird groups is attributable to mosaic properties directly amenable to management by landowners. Key implications include (1) conservation goals for farm landscapes must be carefully defined because the richness of different faunal components is influenced by different mosaic properties; (2) the extent of native vegetation is a critical influence in agricultural environments because it drives the farm-scale richness of woodland birds and has a broader context effect on total bird richness in mosaics; (3) land-use practices that enhance the heterogeneity of farmland mosaics are beneficial for native birds; and (4) the cumulative effect of even small elements in farm mosaics contribute to the structural properties of entire landscapes.     

The effects of disturbance based management on the dynamics of Mediterranean vegetation: A hierarchical and spatially explicit modeling approach

The eastern Mediterranean region has been subjected to intensive human disturbance in the past 10,000 years, mainly in the forms of agro-pastoral activities such as grazing, shrub clearing, and prescribed burning. This disturbance history resulted in the formation of highly heterogeneous landscapes, characterized by high biodiversity. Recent changes in human activities have resulted in a decrease of landscape heterogeneity, leading to decreasing biodiversity and increasing fire risk. To conserve heterogeneity, land managers apply disturbance based management practices, using the same activities that created and maintained landscape heterogeneity in the past. However, the long-term and large-scale outcomes of these disturbances are often unknown, due to the complex response of Mediterranean vegetation to disturbance. Here we report on a spatially explicit, hybrid, and spatially hierarchical ecological model developed by us. The model attempts to predict the outcome of various disturbance based management activities on the long-term spatio-temporal dynamics of five common Mediterranean vegetation types. The model uses a spatially explicit state and transition formulation, with continuous transition functions. Model simulations were conducted on a Mediterranean landscape in Northern Israel, incorporating various disturbance practices that are common in the region. Simulation results highlight the potential of disturbance based management as a tool for conserving landscape heterogeneity, as well as the complex interactions between disturbances and the spatial structure of the landscape in Mediterranean regions.     

Emergent conservation outcomes of shared risk perception in human-wildlife systems

Human perception of risks related to economic damages caused by nearby wildlife can be transmitted through social networks. Understanding how sharing risk information within a human community alters the spatial dynamics of human-wildlife interactions has important implications for the design and implementation of effective conservation actions. We developed an agent-based model that simulates farmer livelihood decisions and activities in an agricultural landscape shared with a population of a generic wildlife species (wildlife-human interactions in shared landscapes [WHISL]). In the model, based on risk perception and economic information, farmers decide how much labor to allocate to farming and whether and where to exclude wildlife from their farms (e.g., through fencing, trenches, or vegetation thinning). In scenarios where the risk perception of farmers was strongly influenced by other farmers, exclusion of wildlife was widespread, resulting in decreased quality of wildlife habitat and frequency of wildlife damages across the landscape. When economic losses from encounters with wildlife were high, perception of risk increased and led to highly synchronous behaviors by farmers in space and time. Interactions between wildlife and farmers sometimes led to a spillover effect of wildlife damage displaced from socially and spatially connected communities to less connected neighboring farms. The WHISL model is a useful conservation-planning tool because it provides a test bed for theories and predictions about human-wildlife dynamics across a range of different agricultural landscapes.     

上海市沿海防护林下土壤养分、微生物及酶的典型相关关系

以上海市沿海防护林为研究对象,选择6种不同树种的防护林带,采集0～10、10～20、20～40、40～60cm四层土样为研究材料,运用典型相关分析法,对防护林地土壤养分因子、微生物因子和酶活性因子中每两组变量间的相关性进行了分析。结果表明：三组变量土壤养分、微生物、酶活性中,每两者之间均有显著的典型相关变量存在,而且基本能够代表变量总体相关信息;土壤养分和土壤微生物间的相关主要由全氮、速效磷含量与微生物生物量氮、微生物生物量碳和微生物生物量磷引起;土壤养分与土壤酶活性间的相关性主要由全氮、有效磷、水解氮含量与脲酶、蛋白酶活性的相关性引起;土壤微生物与土壤酶活性间的相关性主要是由微生物生物量氮、微生物生物量磷与脲酶、蛋白酶、碱性磷酸酶活性的相关性引起;不同林地不同土壤层次的养分、微生物及酶活性在各对典型变量上的聚集趋势可为防护林建设过程中的树种选择与土壤健康诊提供一定的依据。     

Ecological effects associated with land-use change in China's southwest agricultural landscape

Research on land-use and land-cover change, with associated effects on the ecoenvironment, is a key to understanding global change. The concept of 'ecosystem services' is also a hot issue in ecology and ecological economics. In this study, ecosystem service values are used to assess the ecological values of corresponding land-use types, so as to evaluate the ecological effects of regional land-use change. China's southwest agricultural landscape has unique ecological functions; but it also belongs to an ecologically fragile zone. Consequently, land-use change and associated ecological effects must be monitored to assure sustainable development of this area. Based on TM images in 1988, 1994 and 1999, the landscape classification maps of Yongsheng County were assessed using supervised classification and interactive modification methods. The transition matrix of land-use types and three indices of spatial patterns, patch-level, class-level and landscape-level indices, were calculated using models and GIS to examine the spatial patterns and dynamics of land use in the study area. The results show the influences of human activities and natural environmental elements, and that unused land has decreased rapidly, together with a continuous increase in forest during the past 11 years. There are also frequent intermediate transitions between farmland and unused land. An index for landscape diversity shows a tendency to increase, indicating that the proportions of each landscape element tended to average. Also, the decrease in the fractal dimension of unused land reveals that the effects of human activity are increasing. Ecological value calculations show that land-use change in Yongsheng County from 1988–1999 has resulted in positive ecological effects, with distinct spatial differences.     

土壤、土地利用多样性及其与相关景观指数的关联分析

土壤作为人类赖以生存的物质基础,与土地利用之间存在密切联系,土壤类型及属性的差异很大程度上决定了土地利用的方式,同时土地利用方式的不同也间接地改变着土壤类型、性质及功能多样性的格局。在人地矛盾、人与自然矛盾不断加剧的今天,研究土地和土壤的空间分布格局变化及两者之间的交互关系具有重要意义。利用土壤多样性理论和景观生态学原理综合分析土壤、土地利用类型的空间分布格局,并借助空间网格的概念量化分析土壤和土地利用类型的空间分布情况。以河南省中南部样区为研究对象,利用仙农熵变形公式计算了1 km×1 km、3 km×3 km、5 km×5 km 3种网格尺度下的土壤和土地利用的空间分布多样性和各县市的土壤和土地利用构成组分多样性,运用ArcGIS探讨了多样性指数与景观指数之间的关联性,综合评价研究区的土壤类型空间分布与土地利用空间分布格局的相互性。研究表明：同一种土壤和土地利用类型的空间分布多样性指数在异网格尺度下具有相似的分异规律;土地利用与土壤类型的构成组分多样性之间不具有明显的相关性,土壤类型均匀分布的地区,土地利用类型不一定会均匀分布,而两者的平均斑块面积之间具有明显的相关性,土壤斑块的大小对土地利用斑块的大小影响较大,土壤类型的空间分布特征在一定程度上,将影响土地利用的空间分布格局和变化过程;土壤类型的面积指数、平均斑块面积指数分别与土壤空间分布多样性之间具有较好的相关性,相关系数分别为r2=0.990、r2=0.599。而土地利用的面积指数、平均斑块面积指数与土地利用空间分布多样性指数之间的相关性较差,相关系数分别为r2=0.437、r2=0.034。土壤的平均斑块形状指数与多样性指数之间存在一定正相关关系,相关系数为r2=0.612;但土地利用的形状指数与多样性之     

Red soil geochemistry in a semiarid Mediterranean environment and its suitability for vineyards

A geochemical study of a red soil derived from plioquaternary materials was carried out. The soil was located in a region of complex geomorphology and pedologic evolution, with particular characteristics of a Mediterranean climate associated with processes of alteration, rubification, gleying (hydromorphism) and argillization. The depth distribution of 27 trace elements was studied in order to determine the amounts of these elements in the soil and its tendency. The mineralogy of the clay fraction was also studied along with other physico-chemical properties to elucidate in terms of attributes meaningful for viticulture. The geochemical composition of the horizons was studied. The effect of human activities on the soil was investigated as well as the geographical origin of Mancha wines. It was found that these activities did not give rise to significant variations of trace elements, although a discontinuity related to the accumulation of new materials was detected. Ultimately, using established productivity standards, suitability for the cultivation of vines on these soils was determined.     

Urban forest landscape patterns in Ma'anshan City,China

The landscape pattern of Ma'anshan City was analyzed based on theories and methodologies of landscape ecology, remote sensing, global positioning, and a geographic information system (GIS). The study area encompassed the entire built-up area of 63.88 km²; a north–south transect 3-km wide and 13-km long was established along the long axis of the city. Five major landscape elements were assessed: urban land, urban forest, agriculture, water, and grass. Urban land was the dominant land cover type, and occupied 67% of total land area; while patches of urban forest occupied 16%, with a landscape element dominance of 0.42. Urban forest was classified according to land-use category and location into six types: scenic forest, yard forest, recreational forest, roadside forest, shelter forest, and nurseries. There were 2464 urban forest patches, the largest being 185.1 ha, with an average of 0.43 ha. The low nearest neighbor index and high patch density indicated that urban forest patches tend to be aggregated and have a high degree of fragmentation. This study also demonstrated that the spatial pattern of urbanization could be quantified using a combination of landscape metrics and gradient analysis. Urban forest has distinct spatial characters that are dependent on specific landscape metrics along the urbanization gradient.