Relationship between distributions of threatened plants and protected areas in Britain

The establishment and maintenance of a system of protected areas is central to regional and global strategies for the conservation of biodiversity. The current global trend towards human population growth and widespread environmental degradation means that such areas are becoming increasingly isolated in fragmented habitat islands. In regions in which this process is well advanced a high proportion of species are thus predicted to have become restricted to protected areas. Here using uniquely detailed datasets for Britain, a region with close to the global level of percentage coverage by statutory protected areas, we determine the extent of restriction of Red List vascular plant species of conservation concern to these areas. On the basis of currently known distributions, overall our results strongly support the importance of a dual conservation strategy in Britain, in which protected areas are maintained with particular reference to those biodiversity features (such as many threatened plant species) that are highly dependent on them, and in which components of the wider landscape are also managed in such a way as to promote the abundance and distribution of such features with particular reference to those which are unlikely to persist in protected areas alone.     

Spatial patterns of ecohydrologic properties on a hillslope-alluvial fan transect,central New Mexico

Spatial patterns of soil properties are linked to patchy vegetation in arid and semi-arid landscapes. The patterns of soil properties are generally assumed to be linked to the ecohydrological functioning of patchy dryland vegetation ecosystems. We studied the effects of vegetation canopy, its spatial pattern, and landforms on soil properties affecting overland flow and infiltration in shrublands at the Sevilleta National Wildlife Refuge/LTER in central New Mexico, USA. We studied the patterns of microtopography and saturated conductivity (Ksat), and generally found it to be affected by vegetation canopy and pattern, as well as landform type. On gently sloping alluvial fans, both microtopography and Ksat are high under vegetation canopy and decay with distance from plant center. On steeper hillslope landforms, only microtopography was significantly higher under vegetation canopy, while there was no significant difference in Ksat between vegetation and interspaces. Using geostatistics, we found that the spatial pattern of soil properties was determined by the spatial pattern of vegetation. Most importantly, the effects of vegetation were present in the unvegetated interspaces 2–4 times the extent of vegetation canopy, on the order of 2–3 m. Our results have implications for the understanding the ecohydrologic function of semi-arid ecosystems as well as the parameterization of hydrologic models.     

CITES, sustainable use of wild species and incentive-driven conservation in developing countries, with an emphasis on southern Africa

Over 30,000 species of animals and plants that are, or may be, detrimentally affected by international trade are listed on the Appendices of the Convention on International Trade in Endangered Species of Wild Flora and Fauna (CITES). The Convention aims to regulate transboundary trade in species and their derivatives through a system of permits and certificates, and to ensure that such trade conforms to the principle of sustainability. In the developing world, a considerable component of its biodiversity lives outside protected areas where governments have limited potential to manage wildlife. Based on selected vertebrate and plant species, this paper concludes that: (1) use of wildlife in developing countries is more likely to be an imperative rather than a choice; (2) the legal instruments of CITES have limited capacities to ensure that international trade is sustainable; (3) sustainable use of species is best achieved by gaining the support of affected local communities; (4) community support can be maximized by the devolution of ownership or user rights of species from the state to, e.g., the communal level, and the development of effective economic incentive structures to prevent alternative land-use strategies; (5) countries in southern Africa have pioneered devolution of ownership/user rights to the district/communal level; (6) in combination with effective CITES trade controls, trade opportunities, rather than trade restrictions, are most likely to assist in the development of incentive-driven conservation strategies; (7) to avoid negative incentives and to increase awareness of livelihoods, the international CITES community may need to consider whether CITES Appendices I and II listing decisions should be based not only on biological/trade criteria but also on socio-economic considerations, if it is in the conservation interest of the species concerned; (8) a strategic cooperation with the Convention for Biological Diversity (CBD) could improve strategies for sustainable trade; (9) while incentive-driven conservation can provide significant longer-term potential for the protection of animal and plant species, it may be most difficult to achieve for species whose high-value products have a long tradition in medicinal use and (10) the conditions under which incentive-driven conservation is most likely to promote sustainable use need to be clearly identified.     

大同市南郊区土地利用生态服务价值空间分布及变化

本研究以中国生态服务价值当量因子表为基础计算了大同市南郊区不同土地利用生态服务价值单价,结合该区1987年和2002年Landsat TM/ETM 影像分类数据,借助Fragstats和ENVI软件支持进行了矩形单元土地利用生态服务价值的空间模拟,然后采用ENVI的波段运算功能、分类功能进行大同市南郊区土地利用生态服务价值空间分布及变化研究。结果显示:大同市南郊区1987年和2002年土地利用正生态服务区面积大于负生态服务区面积,但生态服务质量等级都不高。1987年平原区生态服务质量好于山丘区,2002年山丘区生态服务质量好于平原区。大同市南郊区从1987年至2002年土地利用生态服务增加区面积大于减小区,且以轻度增加为主。平原区生态服务增加区面积小于山丘区,生态服务减小区面积大于山丘区。平原区生态服务增加区面积小于减小区面积;山丘区生态服务增加区面积大于减小区面积。     

Land use and habitat gradients determine bird community diversity and abundance in suburban, rural and reserve landscapes of Minnesota, USA

Bird species’ community responses to land use in the suburbanizing Twin Cities, Minnesota, USA, were contrasted among reserves, rural lands, and suburbs. For each land use type, bird composition, diversity, and abundance were recorded for 2 years in ≈99 plots in three sampling units (each ≈4500 ha). A habitat gradient defined by canopy structure (grasslands to savannas to forests) was influenced by land use, so ≈300 plots were used to characterize simultaneous variation in bird communities along land use and habitat gradients. At broad scales (aggregate of 33 plots covering ≈4500 ha) suburbs supported the lowest bird richness and diversity and rural landscapes the most, with reserves slightly below rural. Although reserves were like rural lands in diversity of bird communities, they supported more species of conservation concern, particularly of grasslands and savannas. Differences among land use types varied with habitat structure. Suburbs, rural lands, and reserves had similar forest bird communities, but differed in grassland and savanna bird communities. The extensive rural forests are important for the region’s forest birds. Suburban grasslands and savannas had low shrub abundance, low native bird richness and high non-native bird richness and abundance. However, total bird richness and diversity were as high in suburban as in rural and reserve plots because high native richness in suburban forests and high non-native species richness in suburban grasslands and savannas compensated for lower native richness in suburban grasslands and savannas. Bird conservation here and in the Midwest USA should protect rural forests, expand grasslands and savannas in reserves, and improve habitat quality overall.     

Rapid eradication of feral pigs (Sus scrofa) from Santa Cruz Island, California

Eradication of invasive alien species from islands is often necessary to protect native biota. The rapidity in which eradication projects are implemented can help reduce risk they will fail. We describe the eradication of feral pigs (Sus scrofa) from Santa Cruz Island, California, highlighting those control techniques that removed the most pigs and those that removed the last pigs. In 411 days, a total of 5036 pigs were removed from the 25,000-ha island. Before the eradication began, the island was fenced into five zones. Within each zone, the same general sequence of control methods was used: trapping (16% of dispatches in 1660 trap-nights); aerial shooting from a helicopter (77% of dispatches in 13,822 km of flight path); and then ground-based hunting with trained dogs (5% of dispatches in 1111 hunter-days). Sterilized adult pigs fitted with radio collars were subsequently used to aid in the location of surviving wild pigs and to monitor the success of the project. Female telemetered pigs were more effective than males at locating remaining wild pigs. Only 10% of the last 102 pigs (the last 20 or so present in each fenced zone) were dispatched as a result of being found with a telemetered pig, but telemetered animals were responsible for finding 43% of the very last pigs once normal hunting had ceased. The time taken to eradicate pigs on Santa Cruz Island was about half that taken on a neighbouring island of similar size (Santa Rosa Island) and 12 times as fast as that on Santiago Island (58,465 ha), Galapagos Islands. The deliberate sequencing of control methods, using first those that taught surviving pigs the least, and the intensive implementation of those methods, represent important advances in the practice of eradication and so biodiversity conservation.     

额济纳不同植被覆盖类型土壤氮素时空分异特征

量化土壤时空变化对生态系统模型、精准农业和自然资源管理有重要意义。为了更好地控制环境问题,本文把传统统计方法、地统计学方法和地理信息系统三者结合起来,研究了中国西北部额济纳旗(1480 km~2)不同植被覆盖类型土壤氮的时空变化。于2011年与2015年从49个样点采集了98个0~15 cm土壤样品,测量了土壤全氮和硝态氮的含量,比较了不同植被覆盖类型土壤全氮和硝态氮的空间变化和时间变化。结果表明:土壤全氮含量明显受植被覆盖类型影响;土壤全氮平均值变幅为0.259~0.904 g kg~(-1),胡杨林地土壤全氮含量柽柳地土壤全氮含量梭梭地土壤全氮含量;2011年与2015年同一植被覆盖类型下土壤全氮含量差异不显著;2011年胡杨林地、柽柳地、梭梭地土壤硝态氮含量分别为45.185 mg kg~(-1)、76.95mg kg~(-1)、39.335 mg kg~(-1),2015年胡杨林地、柽柳地、梭梭地土壤硝态氮含量分别为2.259 mg kg~(-1)、21.546 mg kg~(-1)、14.554 mg kg~(-1);胡杨林地和柽柳地土壤全氮呈中等强度空间相关性,梭梭地土壤全氮呈强空间相关性;植被覆盖类型明显影响着植被中氮的转移、转化和吸收;研究区土壤氮素含量呈现剧烈的时空变化。     

基于多元回归的黄土沟壑区小流域土壤水分空间模拟

以延河流域羊圈沟为研究对象,基于土壤水分空间自相关理论,在土壤水分环境影响因子多元回归基础上,建立了土壤水分空间化模型,并探讨了土壤水分空间分布特征。结果表明:研究区内土壤水分空间分布具有正相关性,且相关性显著,在空间上表现为聚集状态;表层土壤水分与植被覆盖度、高程、坡度、地表粗糙度、地形起伏度和地表切割程度等因素密切相关,且与地表切割程度呈正相关关系,而与植被覆盖度、高程、坡度、地表粗糙度以及地形起伏度因子呈负相关;与普通克里格(OK)、反距离加权(IDW)、径向基函数(RBF)和全局多项式(GPI)的土壤水分空间内插方法相比,多元回归+普通克里格方法(MROK)的拟合程度最高,是表层土壤水分空间化较好模型;土壤水分空间分布格局明显,主要表现为西部和东北部土壤水分含量低,东南部土壤水分含量高。该研究揭示了土壤水分环境因子相关性及空间分异规律,对区域生态文明建设具有一定的促进意义。     

退耕生态系统碳储量时空动态变化的研究进展

退耕还林还草作为土地利用方式改变的重要形式之一,对退耕生态系统碳储量产生深远影响。从时间、空间以及退耕还林还草模式等方面综述了退耕还林还草对植被碳库和土壤碳库产生的影响,同时探讨了枯落物和根系周转对土壤碳库动态的效应。现有研究表明,退耕生态系统碳储量对退耕时间、空间和模式有不同程度的响应。最后,提出了退耕生态系统碳储量时空动态研究需解决的关键问题。     

多尺度下崇义县耕地质量空间分布差异特征研究

耕地质量优劣既取决于质量等别高低,又与空间分布特征密切相关。研究多层次的耕地质量内涵与空间结构性特征是加强耕地保护并合理配置土地资源的重要依据。本文以南方丘陵山地典型区域崇义县为例,运用Geoda、GS+等平台支持的空间自相关模型,探讨县级、乡镇级与村级空间尺度下耕地自然质量、利用质量与经济质量的空间相互作用和分布规律。结果表明：1）崇义县耕地质量存在显著相关性,耕地质量的Moran’s I值呈现自然质量（0.445） > 经济质量（0.406） > 利用质量（0.281）的特征;2）不同空间尺度下耕地质量具有多样的空间尺度效应,随着空间尺度缩小,自然质量差异最大、经济质量次之、利用质量差异最小,大空间尺度弱化了耕地质量的空间聚集差异特征,村级尺度下耕地质量空间聚集效应最显著;3）耕地质量正相关HH （高-高）型和LL （低-低）型多以团状或带状集中分布,负相关HL （高-低）型和LH （低-高）型无明显分布规律。研究结果揭示了耕地自然质量、利用质量与经济质量对于尺度变化的响应规律,对于各级行政主体监测保护耕地及制定精准高效的耕地质量建设方案具有一定的现实意义。     

Prescribed burning effects on soil physical properties and soil water repellency in a steep chaparral watershed, southern California, USA

Chaparral watersheds associated with Mediterranean-type climate are distributed over five regions of the world. Because brushland soils are often shallow with low water holding capacities, and are on slopes prone to erosion, disturbances such as fire can adversely affect their physical properties. Fire can also increase the spatial coverage of soil water repellency, reducing infiltration, and, in turn, increasing overland flow and subsequent erosion. We studied the impacts of fire on soil properties by collecting data before and after a prescribed burn conducted during Spring 2001 on the San Dimas Experimental Forest, southern California. The fire removed the litter layer and destroyed the weak surface soil structure; leaving a thin band of ash and char on top of, and mixed in with, an unstable, granular soil of loose consistency. Median litter thickness and clay content were significantly decreased after fire while soil bulk density increased. At 7 d post-fire, soil surface repellency in the watershed was significantly higher than prior to the burn. At 76 d post-fire, surface soil water repellency was returning to near pre-fire values. At the 2 and 4 cm depths, 7 d post-fire soil repellency was also significantly higher than pre-fire, however, conditions at 76 d post-fire were similar to pre-fire values. Variability in soil water repellency between replicates within a given 15 × 15 cm site was as large as the variability seen between sites over the 1.28 ha watershed. The increase in post-fire persistence of water repellency was largest beneath ceanothus (Ceanothus crassifolius) as compared to a small increase beneath chamise (Adenostoma fasciculatum). However, pre-fire persistence was higher under chamise than for ceanothus. Post-fire changes to soil properties may increase the watershed hydrologic response, however the mosaic distribution of water repellency may lead to a less severe increase in hydrologic response than might be expected for a spatially more homogenous increase in repellency.     

基于水土保持的宜宾市土地利用空间重组

该文在GIS技术支持下分析了宜宾市水土流失与土地利用间的相互关系,以期为宜宾市土地利用空间重组提供战略思路。结果表明,水土流失多发生在自然因素与人类活动强度吻合较好的地方。因此,土地利用空间重组的目标即是通过土地利用的调整,规避生态敏感区或以能够逆向调节区域生态敏感性的方式利用土地,以有效的减缓水土流失。该文还提出了宜宾市土地利用空间重组的基本模式,即“结构调整+空间集聚”。     

玛纳斯河流域土壤类型空间分布格局分析

以玛纳斯河流域为例,运用G IS技术和景观生态学原理,对土壤类型空间分布格局进行了定量分析,得出以下结论:(1)玛纳斯河流域各土壤类型的分离度指数大多集中在0~3之间,各土壤类型的分布相对比较集中;(2)玛纳斯河流域土壤空间分形结构特征客观存在;(3)玛纳斯河流域各土壤类型的斑块形状复杂性差距较大。分维数最大的是草甸盐土,为1.709,土壤斑块的镶嵌结构最复杂。平均形状指数最大的是新积土,为3.684,土壤斑块的长短轴之比较大,斑块形状偏离正方形或圆形的程度较大;(4)玛纳斯河流域土壤类型多样性指数为3.037,均匀度指数为0.803,表明研究区内各土壤类型的异质性和多样性较高;(5)土壤类型的优势度指数为2.465,斑块密度指数为0.027,表明流域内的土壤是由半固定风沙土等少数几种土壤类型所控制。     

Vegetation diversity in an interconnected ephemeral riparian system of north-central Arizona, USA

A vegetation survey was conducted in the Pumphouse Wash canyon system, south of Flagstaff, Arizona. Plant species distribution, abundance, and diversity were quantified within and among canyons in this sensitive ephemeral riparian area. Abiotic variables were examined to see if they could predict vegetation diversity. Results of stand ordination and cluster analysis suggested that variation in vegetation distribution and composition was best explained by a complex temperature/moisture - substrate gradient. Understory diversity in general was related to changes in slope and sand/gravel substrate. Each tributary canyon supported unique plant species and the riparian vegetation in one tributary canyon was significantly less diverse than in each of the other canyons. The two canyons with the lowest understory diversity contained rare plant species not found in the other, more diverse canyons. Thus, overall diversity was demonstrated to be a poor predictor of the presence of rare species. Similarly, abiotic variation was useful at predicting diversity levels but was not useful at predicting species occurrence or ecological quality. In summary, attributes frequently considered of use for predicting conservation value of one type (e.g., diversity) were not good at predicting other conservation values (e.g., rarity).     

亚热带四种主要植被类型土壤细菌群落结构分析

应用PCR-DGGE方法分别对天目山和玲珑山的四种典型森林土壤细菌群落结构进行了研究分析。结果表明,阔叶林、杉木林、马尾松林和毛竹林在天目山土壤中的DGGE条带数分别为49、45、51和51条,在玲珑山土壤中的DGGE条带数分别为42、4i多是奥前啊2、44和48条。不同森林植被土壤DGGE带谱差异不明显,天目山和玲珑山4种森林土壤分别有31条和23条共性条带,分别占总数的61%和48%以上,然而每种林分也有各自的特征条带。相对而言,两个样地杉木林与其他三种林分的土壤细菌群落结构相似度较低,相似值分别为0.72和0.68,其土壤细菌多样性指数也明显低于其他3种林分,而毛竹林和马尾松林多样性指数则没有显著差异。同时分析两个采样区的土壤细菌DGGE发现,土壤性质对细菌群落结构的影响大于植被。     

Spatial distribution pattern changes of oasis soil types in Manasi River Basin,arid northwestern China

Soil distribution pattern play a significant role in the stability conservation and economic development of oasis in arid regions. Hence, ecologists and agrology scientists have a central interest in understanding the spatial distribution changes of soil types. The aim of this study was to analyze the main processes of soil distribution pattern changes from 1987 to 2006 through the landscape indexes. Soil types and soil distribution pattern changes were assessed and compared by using two soil maps made in 1987 and 2006. 14 soil types were classified and analyzed in the study area. Results indicated many differences among the changes of different soil types. During the period from 1987 to 2006, there were widespread changes in spatial distribution of soil types in Manasi River Basin at class-level. The area of Petrocambids decreased, whereas Aquicambids increased. The small patches began to coalesce into large ones and the patch numbers decreased during the past 20 years, which brought about the fragmentation decrease in Manasi River Basin. In contrast to the decrease of the patch density, the average patch area of 12 soil types increased. With the increasing man-made disturbance, more soil type patches, especially the agricultural soil patches were close to square in shape. During the recent 20 years, the decreased patch shape indexes occupied about 57% of all while the increased patch shape indexes were over 40%. The split index of most soil types has also declined during the same period. The landscape-level indexes also reflected the spatial distribution changes of oasis soil types. The landscape diversity index and landscape evenness index have increased while the landscape dominance index has decreased in the recent 20 years, which showed that more equirotal soil patches were formed and various soil types dominated the soil landscape in Manasi River Basin. Changes of different soil types are one of major indictors to show environment changes and impacts of human activities. Therefore, it is necessary to emphasize the study of soil type changes in the arid and semiarid region.     

复杂地貌类型区耕地土壤有机质空间插值方法研究

选择适宜区域特征的高效点面拓展模型对揭示土壤属性空间分布规律具有重要意义。根据不同地貌类型特征在福建省各地级市选取了9个典型县(市、区),利用2008年采集的29 320个样点数据系统评价不同空间插值方法对耕地土壤有机质含量推算精度的影响。结果表明,福建省各典型县耕地土壤有机质平均含量为27.83 g kg-1,变异系数为37.87%,半方差函数以指数模型拟合效果最佳;全省平原或盆地、丘陵和山地分布面积相当的地区(如闽侯县、建瓯市、永定县、涵江区、福鼎市)采用泛克里格法插值的精度较高,山地为主的地区(如大田县)采用简单克里格法插值的精度较高,而以平原、台地为主的地区(如南安市、同安区、漳浦县)采用普通克里格或张力样条函数法插值的精度较高。     

我国不同空间尺度土壤侵蚀的动态变化

近50 a来,我国水土流失(含水蚀、风蚀)总面积呈抛物线形发展态势,水蚀趋势亦然,但风蚀面积则呈连续增长趋势,发展形势较为严峻。强调指出领导重视、科学政策的制定和落实、依靠科技、小流域综合治理、农村经济改善、农村能源得到缓解等,是我国治理水土流失由破坏大于治理到治理大于破坏,走向健康发展的新阶段的重要因素。     

近40年来陕西省耕层土壤pH的时空变化特征

以陕西省耕层土壤为研究对象,利用1980s第2次土壤普查数据和2017年的705个样点分析数据,基于地统计学和ArcGIS分析耕层土壤pH时空变化特征,并采用相关分析和方差分析方法探讨其影响因素,对于陕西农业可持续发展及生态环境保护具有极其重要的意义。结果表明,陕北、关中及陕南地区耕层土壤pH均值依次为8.25、7.91、6.25,分别为弱碱性、弱碱性和弱酸性;各行政区耕层土壤pH排列顺序为延安榆林铜川咸阳渭南西安宝鸡商洛安康汉中。时间上,与1980s相比,陕北和关中耕层土壤呈碱化趋势,陕南耕层土壤呈酸化趋势;各行政区除榆林、安康、汉中和商洛耕层土壤呈酸化趋势,其余各市耕层土壤均呈碱化趋势。空间上,陕北和陕南耕层土壤pH拟合的最优半方差函数模型为线性模型,关中耕层土壤pH拟合的最优半方差函数模型为高斯模型,均表现出较强的空间相关性。陕北耕层土壤pH空间分布呈零星斑状特征,关中和陕南耕层土壤pH空间分布呈东部高于西部特征。坡向、海拔与陕西省耕层土壤pH显著相关,坡度越小,海拔越高,pH越大,不同类型的土壤pH存在差异。建议陕北和关中地区防治土壤盐碱化问题,陕南地区防治土壤酸化问题,以促进农业可持续发展和保障区域粮食安全。     

河北省冬小麦生产空间格局及其控制因素

在气候变化与水资源短缺的背景下,华北平原冬小麦生产面临巨大的挑战,明确冬小麦生产的空间格局及其控制因素,可为本区冬小麦的科学规划管理决策和高效生产提供依据。基于河北省各县市2004—2013年冬小麦单位面积产量与农情资料,以主产区(以县市平均冬小麦播种面积大于总播种面积的20%为标准选取)101个县市为基本研究单元,采用系统聚类分析对河北省冬小麦主产区进行区域划分;利用因子分析方法对冬小麦生产要素进行主成分分析,并利用逐步回归分析方法建立冬小麦产量与主要控制因素主成分之间的关系。结果表明,河北省冬小麦主产区分为4个(Ⅰ~Ⅳ),各区冬小麦产量水平从Ⅰ区向Ⅳ区依次递减,产量变异依次增大,且各区差异均达显著水平(P0.05)。冬小麦产量(Y)与化肥因子(F1)、灌溉因子(F3)、年降水量因子(F4)、年降水量下限因子(F5)有显著的线性回归关系(R2=0.685,P0.05),其中F1、F3分别解释了Y的21.7%、37.4%,F4、F5解释了Y的9.4%。据此说明灌溉是影响河北省冬小麦产量区域差异的首要因素,其次是化肥使用量,而年降水量对产量区域差异影响较小。农药因子(F2)的回归效应不显著,说明冬小麦病虫害发生及防治具有区域随机性变化特点,对冬小麦生产的区域差异不形成显著影响。另外,全省冬小麦播种面积比重与产量水平有较好的区域吻合度(R2=0.409,P0.05),说明在现有管理模式下冬小麦区域布局基本合理,只是在东部低平原沿海的极个别低产县的播种面积明显偏高,结合冬小麦对灌溉条件的依赖性,认为这些县市的冬小麦布局需要慎重审视。