MACROINVERTEBRATE–PRESSURE RELATIONSHIPS IN BOATABLE NEW ZEALAND RIVERS: INFLUENCE OF UNDERLYING ENVIRONMENT AND SAMPLING SUBSTRATE

Responses of macroinvertebrate communities to human pressure are poorly known in large rivers compared with wadeable streams, in part because of variable substrate composition and the need to disentangle pressure responses from underlying natural environmental variation. To investigate the interaction between these factors, we sampled macroinvertebrates from the following: (i) submerged wood; (ii) littoral substrates < 0.8 m deep; and (iii) inorganic substrates in deep water (> 1.5 m) benthic habitats in eleven 6th‐ or 7th‐order New Zealand rivers spanning a catchment vegetation land cover gradient. Cluster analysis identified primary site groupings reflecting regional environmental characteristics and secondary groupings for moderate gradient rivers reflecting the extent of catchment native vegetation cover. Low pressure sites with high levels of native vegetation had higher habitat quality and higher percentages of several Ephemeroptera and Trichoptera taxa than sites in developed catchments, whereas developed sites were more typically dominated by Diptera, Mollusca and other Trichoptera. Partial regression analysis indicated that the combination of underlying environment and human pressure accounted for 77–89% of the variation in Ephemeroptera, Trichoptera and Plecoptera taxa richness, %Diptera and %Mollusca, with human pressure explaining more variance than underlying environment for %Mollusca. Analysis of replicate deepwater and littoral samples from moderate gradient sites at the upper and lower ends of the pressure gradient indicated that total Trichoptera and Diptera richness and %Diptera responded to land use differences in these boatable river catchments. Responses to human pressure were substrate specific with the combination of littoral and deepwater substrates providing the most consistent response and yielding the highest number of taxa. These results indicate that multiple substrate sampling is required to document the biodiversity and condition of boatable river macroinvertebrate communities and that spatial variation in the underlying natural environment needs to be accounted for when interpreting pressure–response relationships. Copyright © 2012 John Wiley & Sons, Ltd.     

Reptile community responses to native and non‐native riparian forests and disturbance along two rivers in Arizona

Aridland riparian forests are undergoing compositional changes in vegetation and wildlife communities due to altered hydrology. As flows have been modified, woody vegetation has shifted from native‐tree dominated to non‐native and shrub encroached habitats. Squamate vertebrates such as lizards and snakes are important food web links in riparian ecosystems of the Sonoran Desert. However, little is known about how these communities might respond as riparian forests transition from native tree dominated habitats to open xeroriparian woodlands. We used pitfall arrays deployed across three types of riparian forest to document reptile community patterns, measure vegetation, and produce species‐habitat models. Riparian forests differed on the basis of habitat composition and physiognomy. Two types, cottonwood‐willow (Populus‐Salix) and mesquite (Prosopis) stands, were characterized by high woody species richness. The third type, non‐native saltcedar (Tamarix) stands, had high densities of woody debris and greater canopy coverage. Results show that lizards were common and abundances greatest in cottonwood‐willow, especially for arboreal species. Species‐habitat models for three of five lizard species indicated a negative association to saltcedar‐invaded habitat and no species appeared to select saltcedar‐dominated habitat. Mesquite was an intermediate habitat between upland and riparian, and supports high species diversity. A wildfire in the cottonwood‐willow forest disproportionately affected abundance of ground‐foraging whiptail (Aspidoscelis) lizards; whereas, abundance of arboreal spiny (Sceloporus) species was unchanged. Expected drivers from climate and water use could transition cottonwood forests to other woody‐dominated types. Our results suggest that mesquite woodlands would provide higher quality habitat for riparian reptiles compared to non‐native saltcedar stands.     

论水生态系统五大生态要素特征

水生态完整性是指水生态要素的完整性。各生态要素交互作用,形成了完整的结构和功能。生态要素各具特征,对整个水生态系统产生重要影响。水生态要素特征概括起来共有五项,即水文情势时空变异性;河湖地貌形态空间异质性;河湖水系三维连通性;适宜生物生存的水体物理化学特性范围以及食物网结构和生物多样性。河湖生态修复的任务是修复水文、地貌、水体化学物理性质和生物这些生态要素,部分恢复水生态要素的特征。     

Macroinvertebrate Assemblages in Mountain Streams with Different Streambed Stability

Benthic macroinvertebrates are organisms primarily living in the streambed. The stability of the streambed is of vital importance to macroinvertebrate assemblages. Measurement of the streambed stability and sampling of macroinvertebrates were performed from 2005 to 2011 in four mountain streams: the Shengou, Diaoga, Jiangjia and Dabaini Rivers, which have different stability and are all located in the Yunnan plateau in southwestern China. The Shengou, Diaoga and Jiangjia Rivers are composed of gravels and cobbles, and the Dabaini River is mainly composed of gravels. The streambed stability was determined by the ratio of time over the sum of erosion and deposition areas of sediment per unit streambed width at each measured cross‐section. The Shengou River had the highest stability, followed by the Diaoga and Jiangjia Rivers. The Dabaini River had the lowest stability. A total of 70 taxa of macroinvertebrates belonging to 45 families and 68 genera were identified in these streams. Arthropods were the dominant taxonomic group. Collector gatherers had the highest density. Taxa richness, Shannon–Weaver index and K‐dominance curve were used to assess the biodiversity of macroinvertebrates. Results showed that the Shengou River had the highest biodiversity, followed by the Diaoga and Jiangjia Rivers. The Dabaini River had the lowest biodiversity. The detrended correspondence analysis ordination indicated that the streambed stability was the main factor that influenced macroinvertebrate assemblages, counting for 22.7% of the variance. The biodiversity and wet weight of the macroinvertebrates were highly dependent on the streambed stability. The biodiversity increased with the streambed stability and reached equilibrium when the stability was over 20 year m^?1. The wet weight of macroinvertebrates showed an increasing trend with the streambed stability. However, no clear relation was identified between the density of macroinvertebrates and the streambed stability. It was concluded from this study that, in order to improve the ecological condition within the mountain streams, erosion and sedimentation must be controlled to enhance the streambed stability. Copyright © 2014 John Wiley & Sons, Ltd.     

A spatial assessment of riverine ecosystems and water supply in a semi‐arid environment

A spatial assessment was conducted in the semi‐arid area of South Africa, to: (1) identify priority areas for the conservation of river and groundwater ecosystems; (2) examine surface and groundwater quality for human consumption and (3) investigate the rehabilitation of degraded areas to highlight ‘win‐win’ situations for both environmental and human use. A systematic conservation plan was produced, highlighting river conservation areas (river types, fish species and connectivity areas), moderate‐impact management areas (groundwater‐surface water interaction and recharge areas) and river rehabilitation areas. The proposed river selections would achieve the biodiversity targets of 33 (66%) of the 50 river types; feasible rehabilitation would increase this to 92%. The greatest groundwater‐surface water interaction and recharge (30 to > 50 mm^?1) values are concentrated around the mountainous regions of the Little Karoo. This is because the main aquifers in the mountains, table mountain group (TMG) quartzites, yield naturally good quality water for human consumption. River reaches of unacceptable surface water quality were classified as degraded water resource delivery areas where the poor water quality was primarily due to saline return flows from irrigation and the impacts of other anthropogenic activities including abstraction of freshwater which otherwise would have diluted the return flows. Only the middle reaches of the Gouritz and Groot Rivers represent a possible win–win situation for both the environment and human use. Copyright © 2010 John Wiley & Sons, Ltd.     

基于本土生物多样性恢复的近自然城市 生命地标构建理念及其在上海的实践

针对城市发展过程中生物多样性丧失及其引发的都市病,以更好地促进城市本土生物多样性的恢复,依据生态建设应具有生命观、动态观、系统观的都市生态哲学观,提出了城市近自然生命地标的构建理念,即营造以乡土植物及土著动物为主体的近自然型"地标性"生物群落,使其成为能够表征城市区域特征的生命新地标。并以此理念为指导,在上海浦东新区高东镇开展了近自然城市生命地标构建实践,建立了面积为1hm~2的核心示范地。示范地建成1年后,其乡土植物比例高达95%,鸟类、昆虫的物种多样性相较于周边地区分别增加了约30%和50%。     

适应水位变化的鸟类生境修复研究——以 三峡水库澎溪河大浪坝为例

蓄水后三峡水库消落带的剧烈水位变化与反季节水 淹，导致鸟类生境数量与质量的双重衰退，并引发鸟类群落组 成与空间分布的显著变化。针对适应水位变化并恢复鸟类多样 性这一三峡水库生物多样性保护的重要科学问题，选取澎溪河 大浪坝消落带为研究区域，基于栖息、觅食、繁殖及庇护等鸟 类生境综合需求，提出以“环境要素-生物要素-空间结构”协 同设计为核心的鸟类生境修复技术框架。对修复后大浪坝消落 带鸟类群落的结构及多样性变化进行评估，结果表明：鸟类生 境质量显著改善，在不同季节及水位条件下均能维持良好的鸟 类生境异质性，鸟类多样性得到持续提升。研究成果可为复杂 水位变化影响下大型水库消落带的鸟类生境修复与多样性提升 提供科学依据和可参考的技术范式。     

The nature of cultural landscapes — a nature conservation perspective

This paper explores the reasons for the growing interest in cultural landscapes in nature conservation circles. It contains a brief discourse on nature and culture, emphasizing the declining power of the idea of pristine wilderness, the realization that many disturbed ecosystems are important to conservation, that agri-biodiversity is a resource to be protected along with wild biodiversity, and the need to find models of sustainable land use. Examples are given, at the global (World Heritage Convention), European and national levels, of the way in which the growing interest in cultural landscapes manifests itself; special attention is given to the category of protected area known as 'protected landscape/seascape'. Finally, the author identifies the major natural qualities found in cultural landscapes which will assist in understanding, identifying and protecting those features of value.     

Fragmentation of pine flatwood and marsh communities converted for ranching and citrus

Patterns of change are documented for pineland and marsh, two habitats that are significant for 273 of the 326 native terrestrial vertebrates within the Immokalee Rise region of Florida. Area of both habitats, average patch sizes, and association of patches with patches of the same type and different types changed dramatically from ca. 1900 to 1989. Patterns of change were slightly different from ca. 1900 to 1973 and 1973 to 1989, with more large-scale removal of patches occurring in the former time period. Fragmentation of remaining patches was greatest from 1973 to 1989. In addition to loss and fragmentation of habitat, the association of the two habitat types has been altered. Pineland and marsh have become separated from each other thereby altering, if not destroying, the important upland-wetland linkages naturally present in the region. Drawing from previous studies of species-habitat associations and fragmentation impacts on wildlife in other areas, we form some general conclusions on the implications of these changes on regional biodiversity. Species most severely impacted by the change are most likely those requiring large contiguous areas, requiring interior pineland habitat, and those that use both uplands and marsh. It is probably not a coincidence that 65% of the species rare in the region use pineland or marsh. Continued chipping away at the remaining habitat without regard for the importance of the spatial arrangement and regional context will continue to impact regional biodiversity. A regional perspective to agricultural development is needed to maintain the native biodiversity in the region. Efforts should be made to preserve the remaining large tracts of habitat and seek to restore connections between critical habitats. Maintance of biodiversity will require a regional perspective to agricultural development. Large tracts of remaining habitat must be preserved and connections between critical habitat restored.     

气候变化对陆地生物多样性影响研究的若干进展

气候变化对生物多样性影响的研究日益受到重视。文章总结了有关气候变化对基因多样性、物种多样性和生态系统多样性影响研究的趋势,并对存在的问题进行了讨论。目前,气候变化对生物多样性影响的研究总体上还不深入,研究需要加强。