Plant communities along the Medina-Badr road across the Hejaz mountains,Saudi Arabia

The present study gives an assessment of the environmental factors and their effect on the pattern and distribution of the plant communities in the area along the road from Medina to Badr, Saudi Arabia. The road crosses the Hejaz mountains and the study area presents three main ecogeomorphological systems which are differentiated into various habitats. Rainfall and plant cover show wide variation, both in quantity and distribution in the different sectors of the study area. Also, the wide variations in topography, rock types and soil characteristics, have a marked influence on the water resources and consequently on the vegetation.Twenty-three communities, recognized by species dominance and habitat features, have been distinguished. These include ten communities dominated by trees and shrubs; five of them are dominated by one of the Acacia spp. growing in the area. Seven communities are dominated by suffrutescent species and six are dominated by ephemeral species. The latter communities appear only during the wet season and disappear at the beginning of summer. The floristic conoposition and the habitat features are described and the ecological relationships between the communities are briefly discussed.Nomenclature follows Taeckholm (1974) and Migahid (1979).The authors are grateful to Mr S. Ads for his assistance in the field work.Dedicated to Haj Hassan El-Batanouny, deceased and buried at Al-Hamrah, Hejaz in 1911.     

Towards a multimetric index for ecological assessment of Mediterranean flatland ponds: the use of macroinvertebrates as bioindicators

Fifty-five macroinvertebrate metrics were tested for their response to pond condition in 41 ponds of northwest Spain to develop a preliminary multimetric index for ecological assessment of Mediterranean flatland ponds. Stressor specific response of individual attributes to eutrophication and habitat alteration was also investigated to identify differences in the responses of metrics to single stressors and elucidate how this might affect the performance of the final index. Several combinations were tested using discrimination efficiency (25th percentile of slightly impaired sites for metrics decreasing with perturbation and 75th percentile of slightly impaired sites for metrics increasing with perturbation) and Mann–Whitney U-test with Bonferroni adjustment (P < 0.001). The final index comprised five measures (generic richness of Chironominae, generic richness of Dytiscidae + Odonata + Tanypodinae, relative richness of Chironomidae, % Macropelopini and Shannon index) and discriminated between acceptable (good) and unacceptable (moderate) conditions with more than 86% efficiency. Moreover, all the five measures included in the final index showed unidirectional responses to eutrophication, decreasing as eutrophication increased. In contrast, the effect of habitat alteration was less clear, especially in ponds in best available conditions where a vegetation belt of shrubs and trees prevented growing of macrophitic vegetation on shores and consequently associated fauna. Interestingly, none of the functional groups (e.g. % predators and % collector–gatherers) were sensitive to degradation. Handling editor: K. Martens     

建立我国生态补偿机制的思路与措施

建立生态补偿机制是促进我国生态保护、协调区域发展一项重要制度设计.尽管我国在国家、区域、流域等尺度上的生态补偿实践取得了很大进展,但仍存在缺乏系统的制度设计、政府单方面决策为主与利益相关参与不够、补偿范围界定方法不科学、生态补偿对象和补偿方式不完善;补偿标准低与确定方法缺乏科学基础;缺乏监督机制和政策效果不明显等方面不足.围绕统筹人与自然和谐发展的制度建设,提出了建立适合我国国情生态补偿机制的原则,并从以下方面探讨了建立生态补偿机制的措施与对策:科学确定生态补偿地域范围;明确生态补偿载体与补偿对象;建立合理的生态补偿经济标准核算方法;建立和完善生态环境补偿机制的措施,以期为建立协调人与自然和谐发展的制度提供参考.     

公路建设的主要生态影响

公路已成为全球景观中一种重要的景观类型,其里程和密度在逐年增加.公路建设项目,尤其是公路网络的形成不仅减少了自然生境的数量,而且严重降低了自然生境的质量.公路建设对生态环境造成的影响主要包括生境损失、生态干扰、公路致死、阻碍作用、廊道效应以及公路网络造成的严重生境破碎化.缓解公路生态影响的措施有避免、消减和补偿3种.     

Landscape-scale impacts of transportation infrastructure on spatial dynamics of two vulnerable ungulate species in Ghamishloo Wildlife Refuge,Iran

Development of roads through protected areas can have deleterious effects on natural habitats containing species of conservation concern. During the past decades road construction has affected many former remote areas and led to fragmentation and isolation of wildlife populations. The present study focuses on the ecological impacts of Isfahan's West Freeway, which passes through Ghamishloo Wildlife Refuge; an IUCN category IV protected area, in Isfahan Province. The two key affected species, both classified as vulnerable by IUCN, the goitered gazelle (Gazella subgutturosa subgutturosa) and the wild sheep (Ovis orientalis isphahanica) were subject to impact analyses. We used habitat evaluation procedure (HEP) as a habitat-based impact assessment methodology which considers habitat quality and quantity. Habitat quality was measured as habitat suitability index (HSI) for each species. By literature review and field observations, five variables defining habitat suitability were identified and suitability maps for both species generated. Habitat units (HUs) were derived from multiplying the HSI for each species by the habitat area before and after freeway construction. The results showed that due to the construction of the freeway, about 14% of the HUs for goitered gazelle and about 9% of the HUs for wild sheep were lost. In addition, for quantifying landscape pattern change due to freeway construction, various landscape metrics were calculated for the species distribution polygons for two times before and after freeway construction. Results obtained through quantifying landscape metrics showed that mean nearest neighbor (MNN) and number of patches (NP) metrics increased. On the other hand, CONTAG metric decreased in both goitered gazelle and wild sheep distribution polygons, demonstrating the negative effect of freeway on these species distribution polygons integrity. According to the results of this study, mitigation and compensation activities should be considered in Ghamishloo Wildlife Refuge. Our study demonstrated that HEP method combined with quantifying landscape metrics might provide a powerful tool for assessing ecological impact of technical infrastructures on populations of far-ranging species of conservation concern.     

道路生态研究进展

道路广泛分布在各种景观中,其密度和交通量都不断增加,随之带来多方面的生态影响:道路建设导致动植物死亡和生境丧失、物理化学环境变化、路旁植被改变.对动物种群产生的生态影响包括道路致死、道路回避和巢区转移、移动格局改变、障碍作用导致生境和种群的破碎化.道路还强烈地改变景观格局和过程.道路生态影响的定量化测度指数包括道路密度、道路位置和道路影响域,道路生态研究在道路规划和野生动物保护中有很广阔的应用前景,成为生态学的一个重要领域.     

道路生态研究进展

道路广泛分布在各种景观中,其密度和交通量都不断增加,随之带来多方面的生态影响：道路建设导致动植物死亡和生境丧失、物理化学环境变化、路旁植被改变。对动物种群产生的生态影响包括道路致死、道路回避和巢区转移、移动格局改变、障碍作用导致生境和种群的破碎化。道路还强烈地改变景观格局和过程。道路生态影响的定量化测度指数包括道路密度、道路位置和道路影响域,道路生态研究在道路规划和野生动物保护中有很广阔的应用前景,成为生态学的一个重要领域。     

岷江上游生态补偿的博弈论

为了建立合理的生态补偿机制,制定更为科学的生态补偿政策,以岷江上游退耕还林补偿为例,运用博弈论模型考察了岷江上游现有生态补偿机制,以及在补偿政策实践过程中补偿主体与补偿对象之间的决策和行为过程.结果表明:(1)长期来看,生态补偿政策的实施效果不完全在于补偿金额的大小,仅仅依靠提高对生态建设者(保护者)的补偿标准来保护环境是不明智的;(2)生态补偿年限对岷江上游地区生态补偿政策的实施效果起着重要作用,政府制定生态补偿政策时应该将补偿年限纳入政策制定范畴中,并作为重点考虑的因素;(3)岷江上游地区第三产业的发展水平及生态建设者(保护者)外出务工收入水平的高低直接影响生态建设工程实施的效果;(4)对生态补偿的重要策略是应该通过建立相应的配套措施来增加农民务工的机会.     

Study on coastal wetland habitat quality evaluation in Quanzhou Bay, Fujian, China

Coastal wetland is located in the active interface between land and sea, which is one of the richest biodiversity habitats, while it is seriously disturbed and destroyed by anthropogenic activities in both terrestrial and marine parts. Habitat serves as the basis for organism survival, providing food, shelter, water, space and so on, and habitat degradation and loss caused by intense anthropogenic activities is widely considered as the main reason for biodiversity decline and loss. However, there is still limited study on the evaluating methods of coastal wetland habitats, especially for those in a large scale. In this study, methods for evaluating coastal wetland habitat quality, including selecting indicators, setting value assignment criteria and weights were discussed systematically, a method of coastal wetland habitat quality evaluation was established, and the habitat quality in Quanzhou Bay was also evaluated as a case study. The present study provided a new concept and method to assess quantitatively habitat status, indicate the ecological status and its change, and also reflect and predict indirectly the ecological impact of human activities.Referring to the habitat evaluation system (HES) developed by United States in the mid 1970s, the evaluation method was established by thorough analysis of the characteristics of coastal wetland. The habitat indicators were selected in terms of three habitat factors as follows: chemical factors, including dissolved oxygen (DO), phosphate in seawater, sulfide in sediment, and regional priority pollutants; physical factors, including landscape naturalness index and coastline artificialization index; biological factors, including invasive species risk and area ratio of invasive alien species. Weights were established by Analytic Hierarchy Process, combined with several-round expert evaluation. Evaluation criteria providing principles for value assignment of each indicator, were established referring to previous standards and related researches. The final result for assessing habitat quality was indicated and stated by the value of Habitat Quality Index (HQI), which is the weighted sum of each indicator. Habitat quality increased with the HQI value, with value ranging from 0 to 100.The established evaluating method was applied to assess the habitat quality of Quanzhou Bay, located in the southeast coastal zone of Fujian Province, with a total area of 136.4 km², which is an important bay in Fujian. Quanzhou Bay wetland is a typical coastal wetland with diverse wetland habitats, including mangrove, estuary, island, aquaculture ponds, salt pan, shallow sea, mud flat and so on. The Quanzhou Bay is now seriously suffering environmental problems, e.g. eutrophication due to great discharge of domestic, agricultural and industrial wastewater, rapid urbanization and reclamation resulting in decreased wetland area, and the invasion of alien species. The evaluation results showed that the habitat quality index value was 68.13, 57.99 and 51.23 in 1989, 2002 and 2008, respectively, indicating that the habitat degraded gradually. The five major factors that led to decline of HQI value were phosphate in seawater, lead in sediment, landscape naturalness index and coastline artificialization index and area ratio of invasive alien species. Therefore, in order to improve and maintain habitat quality, it is urgent to control pollution, large-scale reclamation and Spartina invasion in Quzhou Bay.     

Effects of road network on Asian elephant habitat and connectivity between the nature reserves in Xishuangbanna,Southwest China

Evaluating road effects on the ecological status and landscape connectivity is critical for animal corridor design. Taking the fragmented nature reserves in Xishuangbanna as a case, road impacts on Asian elephant habitats were determined based on a suitability analysis. Potential corridors between different sub-reserves were located using “least-cost” method as a systematic way incorporating remote sensing (RS) and geographic information system (GIS). Our results revealed that road networks, especially high-level roads (expressway, national road and city-county city road), had the largest effects on the suitability according to the sensitivity analysis. Suitability ( > 40) area will increase about 40% if there were no high-level roads. In total, seven potential linkages were located and found to be capable of connecting the habitats of the four sub-reserves. We suggested the Menglun reserve could serve as a stepping-stone for elephant migration. Four further conservation priorities were also identified between the Menglun reserve and the Mengla reserve where the road impacts were intensive. Our study provided information for the development of an efficient reserve network for elephant conservation between existing nature reserves in China and neighboring provinces in Lao PDR.     

The changing status of the Chalkhill Blue butterfly <Emphasis Type="Italic">Polyommatus coridon</Emphasis> in the UK: the impacts of conservation policies and environmental factors

The Chalkhill Blue Polyommatus coridon is a widespread butterfly of lowland calcareous grassland in southern Britain and is considered a good indicator of habitat condition. Polyommatus coridon has been identified as a Species of Conservation Concern in the UK Biodiversity Action Plan due to a greater than 25% decline in range size since the 1950s, with losses due to the combined effects of habitat destruction, agricultural intensification and neglect. Analysis of annual butterfly monitoring data (transects) collected at 161 sites from 1981 to 2000 show a three-fold population recovery had occurred. The increases were at established sites, with no re-colonisations or range expansion detected. The 1980s population increase coincided with increases across the species range in stock and rabbit Oryctolagus cuniculus grazing, as well as greater protection and management of sites through protected areas and nature reserves. During the 1990s agri-environment schemes were thought to be the main conservation and policy mechanism driving the favourable conservation status of P. coridon, by facilitating appropriate habitat restoration and management. Weather played a part in the species recovery, with warm, but wet summers associated with increases in abundance. The research provides strong evidence of an important conservation success with the UK Biodiversity Action Plan, with implications for other specialist biodiversity.     

Flooding compromises compensatory capacity of an invasive plant: implications for biological control

Plant compensatory growth is proposed to be insidious to biological control and known to vary under different environmental conditions. However, the effects of microsite conditions on compensation capacity and its indirect impacts on biological control of plant invaders have received little attention. Alligator weed, Alternanthera phioxeroides, is an invasive plant worldwide, growing in both aquatic and terrestrial habitats that are often affected by flooding. Biological control insects have been successful in suppressing the plant in many aquatic habitats but have failed in terrestrial habitats. To evaluate the impact of flooding on compensation capacity, we conducted common garden and greenhouse experiments in which plants were grown under different moisture conditions (aquatic versus terrestrial). Our results show that plants were able to fully recover from continued herbivory in the terrestrial habitat, but failed in the aquatic habitat, indicating a flooding-regulated plant compensatory capacity. Also, the grazed plants increased below-ground growth and reproductive root bud formation in the terrestrial habitat, but there was no such difference in the aquatic habitat. Our findings suggest that the differing plant compensatory capacity, affected by flooding, may explain the different biological control efficacy of alligator weed in aquatic and terrestrial habitats. Understanding mechanisms in plant invader compensation in different microsite conditions is important for improving management efficiency.     

Incorporating habitat use in models of fauna fatalities on roads

Aim  To highlight the benefit of using habitat use to improve the accuracy of predictive road fatality models.
Location  The Snowy Mountains Highway in southern New South Wales, Australia.
Methods  A binary logistic regression model was constructed using wombat fatality presences and randomly generated absences. Species-specific habitat variables were included as predictors in the model selection process as well as two spatially explicit measures of wombat habitat use. Generalized additive models (GAMs) were constructed for each possible combination of predictors in R. The final model was selected by comparing all models subsets for the eight predictors and employing the one standard error rule to select the best model set.
Results  The final predictive model had high discriminatory power and incorporated both measures of species habitat use, greatly exceeding the variation explained by a previously published model for the same species and road.
Main Conclusions  Our findings highlight the importance of incorporating variables that describe habitat use by fauna for predictive modelling of animal-vehicle crashes. Reliance upon models that ignore landscape patterns are limited in their capacity to identify hotspots and inform managers of locations to engage in mitigation.     

Patterns of otter Lutra lutra road mortality in a landscape abundant in lakes

In order to reduce otter (Lutra lutra) road mortality and to predict accident sites, we assessed the localities of traffic accidents involving otters in the Uckermark County, Brandenburg, Northeast Germany. Eighty-eight otter accident sites from the years 1990 to 2003—as recorded by the Naturschutzstation Zippelsförde des Landesumweltamtes Brandenburg (Brandenburg State Office for Environment)—were categorised according to traffic and road patterns, otter habitat suitability, as well as presence and type of watercourse crossings. From these numerical data, we compiled a list of characteristics to identify other potentially dangerous sites where otter road traffic accidents are likely to occur using a geographic information system. With a principal component analysis, we categorised three groups of accident sites. Firstly, most otter road accidents were located close to either one or two lakes. Secondly, otters were frequently killed at places where no body of water occurred within a distance of 200 m to the road. Thirdly, and in contrast to other locations, in the Uckermark County, fewest accidents happened where a road crossed a watercourse. Mitigation measures were suggested and discussed for the recorded and potential accident sites.

     

The structure of a nearshore fish community of Western Australia: diel patterns and the habitat role of limestone reefs

Synopsis Extensive limestone reefs are a characteristic feature of much of the coastline of Western Australia, and potentially represent a major habitat feature influencing the structure of the coastal fish community. The structure and temporal dynamics of the fish fauna and its relationships to nearshore patch reefs and surrounding habitat near Dongara, Western Australia, were examined using (1) diel gill-netting and (2) quantitative rotenone sampling of enclosed areas of substratum. Long-term and day-to-day variability of the fauna was low. Dominant species of gill-net collections were either associated with reefs or occurred in similar abundances at both reefs and surrounding sand/seagrass flats. The overall abundance, number of species and biomass of netted fishes was higher around reefs. Rotenone collections of the more sedentary species showed a similar pattern, but suggested, however, that a simple reef versus surrounding sand and seagrass habitat comparison is complicated by the canopy-forming seagrass Amphibolis that occurs on reef tops. Time of day had an important effect on overall fish abundance and number of species, with peaks occurring at crepuscular periods. This reflected dusk and dawn activity peaks of a dominant species rather than overlapping activities of many diurnal and nocturnal species. Diel switches between reef-edge habitat and surrounding sand/seagrass flats were uncommon despite expectations (based on literature examples) that patch reefs would function primarily as sheltering habitats and surrounding non-reef areas act as foraging habitat. High catches at reef-edge sites suggest that the majority of fishes forage on or near limestone patch reefs. Fish densities of around 0.8 individuals per m^-2 of bottom on these Western Australian reefs are relatively high in comparison to visual census estimates obtained for temperate reef systems in South Australia and New Zealand, but similar to those obtained using comparable netting methods in temperate Australian seagrass systems.     

Amphibian road mortality in Europe: a meta-analysis with new data from Poland

While the increasing vehicular traffic is widely suspected to play a role in the worldwide amphibian population decline, the research of amphibian road mortality is scarce, fragmented, fraught with methodological problems, and largely inconclusive. As the first attempt at a synthesis, we analyzed all available data on amphibian mortality in Europe and combined them with four previously unpublished surveys conducted by us. Based on our recalculation of road-kill counts in terms of species-specific road-kill recordability, we conclude that, in lowland Central Europe, the common toads, Bufo bufo, are the most common victims of vehicular traffic in suburban landscapes, while the common frogs, Rana temporaria and Triturus newts, prevail in rural landscapes. The green frogs also tend to be more frequent in rural areas. Common tree frogs, Hyla arborea, are unexpectedly rare in the road-kill record despite their terrestrial and migratory habits. In consideration of problems with obtaining accurate amphibian population estimates, we further propose the road kills-to-spawners ratio (R/S) as a working measure of the impact of road mortality on a local population. While the R/S ratio may not reflect the losses to an entire local amphibian population, it is free of the errors of whole-population estimates, which are notoriously difficult for amphibians. When corrected for species-specific road-kill recordability, most results suggest that the impact of roads on newts may have been underestimated and that the impact on common frog populations may be higher than on those of common toads. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. Communicated by H. Kierdorf     

Challenging the practice of biodiversity offsets: ecological restoration success evaluation of a large-scale railway project

Large-scale infrastructure development projects are discussed transdisciplinarily in several domains of society. Critics often claim that environmental impact assessments lack real influence on planning, management, and monitoring. We report herein the evaluation of ecological compensation via biodiversity offsets and technical constructions with a secondary compensation function for a new railway in Austria. We asked: (1) where can ecological restoration success be detected, and (2) is our new method of a composite biotope value calculation representative for all criteria we used? We conducted a vegetation inventory on reference areas and all types of measures that created new habitats. Together with a comprehensive, spatially dense habitat mapping, evaluation of six attributes of restoration success and testing of our new method were carried out. Current threats typical for intensive agriculture have been generally reduced. Ecological compensation measures had the highest connectivity but the lowest plant community diversity. Surprisingly, technical constructions provided significantly more plant communities and hosted most Red List species. The species assemblage characteristics of compensation measures, their biotope type diversity, and their mean biotope values were, although lower, comparable to the reference. Despite the poor performance of technical areas in the final biotope values, our results call for their reconsideration as potential tools for ecological compensation by greening grey infrastructure in the near future. The tested new method provided an overall statement for the ecological restoration evaluation and could also be used for nature evidence inventories and as a valuable decision support tool in landscape planning.     

Living on the verge: are roads a more suitable refuge for small mammals than streams in Mediterranean pastureland?

The retention of natural habitat corridors is a useful and practical conservation tool that can attenuate the effects of habitat loss and fragmentation on wildlife. Linear structures may contribute to the conservation of biodiversity by providing additional habitats for small fauna living in highly modified environments. We assessed the importance of road verges as refuge areas for small mammals, in highly intensified grazed pastures, within a Mediterranean landscape and compared the role of road verges as refuges with that of riparian galleries, which have been described as important shelter locations for small fauna. For this purpose, a small mammal trapping study was undertaken on two road verges and beside two small streams in southern Portugal. We captured 457 individuals of five different species, with Mus spretus the most common species captured, followed by Crocidura russula. Captures were 4.6-fold higher immediately beside both roads and streams than 12 m away in the surrounding matrix. Individuals captured in the matrix presented a smaller body size and lower body condition, suggesting that this suboptimal habitat is occupied mainly by subadults. M. spretus was 46% more abundant by roads than by streams, while C. russula was present in similar numbers in both habitats. M. spretus individuals were larger near streams but exhibited no difference in body condition between habitats. C. russula had a better body condition and slightly higher body lengths at roadsides. Our results show that roadside verges in intensively grazed Mediterranean landscapes act as important refuges and constitute equally vital habitats for small mammals as do riparian vegetation strips in landscapes where other suitable habitats are scarce.