指示种、伞护种与旗舰种:有关概念及其在保护生物学中的应用

指示种、伞护种和旗舰种等的运用常常可以作为解决保护生物学问题的捷径。指示种被用来评价环境中人为干扰因素的程度,监测其他物种的种群动态,或用于确定生物多样性较高的区域;伞护种则常用来确定需保护生境的类型和面积;而旗舰种被用于引起公众对保护行为的关注。本文试图对上述术语和概念在使用上加以明确区分,并对其应用提出一些指导性原则。认为针对上述不同类型的代理种,使用的目的和选择的标准应有所不同,彼此不能混淆使用。     

Gastropod diversity,distribution and abundance in habitats with and without anthropogenic disturbances in Lake Victoria,Kenya

We investigated freshwater gastropod diversity, abundance and distribution in habitats with and without anthropogenic disturbance in two localities, Ndere in the Winam Gulf and Mbita Point, Lake Victoria, Kenya, from May 2002 to January 2004. A total of 133 984 gastropod specimens belonging to 15 species were recorded, 14 from Mbita and 12 from Ndere. Two species, Ferrissia kavirondica and Cleopatra cridlandi, which were recorded only from undisturbed habitats, could be indicators of least disturbed habitats. Water chemistry did differ between fish landing sites and undisturbed habitats at some sampling times, indicating that differences due to human impact do exist, but these are dependent on periods of calm weather. The study shows that anthropogenic disturbances cause ecological changes that can be exploited by some snail species, especially Biomphalaria choanomphala and Melanoides tuberculata, while other species may not tolerate these changes. In order to protect gastropod diversity and avoid dominance of intermediate hosts, such as B. choanomphala, a management plan for the use of these fish landing sites should be developed. This could include rules on how to dispose of fish remnants and other wastes so as to reduce local eutrophication, thereby reducing risks associated with transmission of potential snail-borne diseases.     

Anthropogenic threats can have cascading homogenizing effects on the phylogenetic and functional diversity of tropical ecosystems

Determining the mechanisms that underlie species distributions and assemblages is necessary to effectively preserve biodiversity. This cannot be accomplished by examining a single taxonomic group, as communities comprise a plethora of interactions across species and trophic levels. Here, we examine the patterns and relationships among plant, mammal, and bird diversity in Madagascar, a hotspot of biodiversity and endemism, across taxonomic, phylogenetic, and functional axes. We found that plant community diversity and structure are shaped by geography and climate, and have significant influences on the taxonomic, phylogenetic and functional diversity of mammals and birds. Patterns of primate diversity, in particular, were strongly correlated with patterns of plant diversity. Furthermore, our findings suggest that plant and animal communities could become more phylogenetically and functionally clustered in the future, leading to homogenization of the flora and fauna. These results underscore the importance and need of multi‐taxon approaches to conservation, given that even small threats to plant diversity can have significant cascading effects on mammalian and avian community diversity, structure, and function.     

Conservation threats and future prospects for the freshwater fishes of Ecuador: A hotspot of Neotropical fish diversity

Freshwater fish communities in Ecuador exhibit some of the highest levels of diversity and endemism in the Neotropics. Unfortunately, aquatic ecosystems in the country are under serious threat and conditions are deteriorating. In 2018–19, the government of Ecuador sponsored a series of workshops to examine the conservation status of Ecuador's freshwater fishes. Concerns were identified for 35 species, most of which are native to the Amazon region, and overfishing of Amazonian pimelodid catfishes emerged as a major issue. However, much of the information needed to make decisions across fish groups and regions was not available, hindering the process and highlighting the need for a review of the conservation threats to Ecuador's freshwater fishes. Here, we review how the physical alteration of rivers, deforestation, wetland and floodplain degradation, agricultural and urban water pollution, mining, oil extraction, dams, overfishing, introduced species and climate change are affecting freshwater fishes in Ecuador. Although many of these factors affect fishes throughout the Neotropics, the lack of data on Ecuadorian fish communities is staggering and highlights the urgent need for more research. We also make recommendations, including the need for proper enforcement of existing environmental laws, restoration of degraded aquatic ecosystems, establishment of a national monitoring system for freshwater ecosystems, investment in research to fill gaps in knowledge, and encouragement of public engagement in citizen science and conservation efforts. Freshwater fishes are an important component of the cultural and biological legacy of the Ecuadorian people. Conserving them for future generations is critical.     

Freshwater biodiversity: importance, threats, status and conservation challenges

Freshwater biodiversity is the over‐riding conservation priority during the International Decade for Action ‐‘Water for Life’ ‐ 2005 to 2015. Fresh water makes up only 0.01% of the World's water and approximately 0.8 % of the Earth's surface, yet this tiny fraction of global water supports at least 100 000 species out of approximately 1.8 million ‐ almost 6% of all described species. Inland waters and freshwater biodiversity constitute a valuable natural resource, in economic, cultural, aesthetic, scientific and educational terms. Their conservation and management are critical to the interests of all humans, nations and governments. Yet this precious heritage is in crisis. Fresh waters are experiencing declines in biodiversity far greater than those in the most affected terrestrial ecosystems, and if trends in human demands for water remain unaltered and species losses continue at current rates, the opportunity to conserve much of the remaining biodiversity in fresh water will vanish before the ‘Water for Life’ decade ends in 2015. Why is this so, and what is being done about it? This article explores the special features of freshwater habitats and the biodiversity they support that makes them especially vulnerable to human activities. We document threats to global freshwater biodiversity under five headings: overexploitation; water pollution; flow modification; destruction or degradation of habitat; and invasion by exotic species. Their combined and interacting influences have resulted in population declines and range reduction of freshwater biodiversity worldwide. Conservation of biodiversity is complicated by the landscape position of rivers and wetlands as ‘receivers’ of land‐use effluents, and the problems posed by endemism and thus non‐substitutability. In addition, in many parts of the world, fresh water is subject to severe competition among multiple human stakeholders. Protection of freshwater biodiversity is perhaps the ultimate conservation challenge because it is influenced by the upstream drainage network, the surrounding land, the riparian zone, and ‐ in the case of migrating aquatic fauna ‐ downstream reaches. Such prerequisites are hardly ever met. Immediate action is needed where opportunities exist to set aside intact lake and river ecosystems within large protected areas. For most of the global land surface, trade‐offs between conservation of freshwater biodiversity and human use of ecosystem goods and services are necessary. We advocate continuing attempts to check species loss but, in many situations, urge adoption of a compromise position of management for biodiversity conservation, ecosystem functioning and resilience, and human livelihoods in order to provide a viable long‐term basis for freshwater conservation. Recognition of this need will require adoption of a new paradigm for biodiversity protection and freshwater ecosystem management ‐ one that has been appropriately termed ‘reconciliation ecology’.     

Insular Freshwater Fish Faunas of Micronesia: Patterns of Species Richness and Similarity

Freshwater fishes are an important but relatively little known component of the highly diverse fish fauna of Micronesia. Localities supporting communities of freshwater fishes include large high islands, with considerable habitat complexity, and smaller low islands, such as atolls and raised coral islands, with limited freshwater habitat. Both types of islands may support species with adult life history styles that are (a) amphidromous and catadromous, (b) euryhaline (often estuarine), or (c) marine species which enter freshwater from time to time. We compared patterns of species richness and similarity between Micronesian localities for amphidromous and catadromous, euryhaline and marine species (ACEM) pooled, and for amphidromous and catadromous species (ACFW). Species richness of both ACEM and ACFW fishes was greatest on larger high islands compared to smaller high and all low islands. Cluster analysis of similarity indices for ACEM species between localities revealed two faunal components: high islands and low islands. High islands were further partitioned into a Caroline Islands cluster and a separate Mariana Islands cluster. Cluster analysis of ACFW species was more complex. One cluster consisted of a low island and a small high island, both in the Carolines chain and with limited freshwater habitat. The second cluster was partitioned into high islands and low islands that reflected influences of both size and geographical location.     

Host-parasite interactions in oligotrophic stream ecosystems: the roles of life-history strategy and ecological niche

Biodiversity in fluvial ecosystems is under pressure as a consequence of their degradation. Conservation strategies for endangered freshwater molluscs and for salmonid fishes have been proposed but they are typically poorly integrated. Here, we examined for the first time the genetic structure of a critically endangered obligate mollusc invertebrate parasite, the freshwater pearl mussel ( Margaritifera margaritifera ), and its vertebrate host fish, the brown trout ( Salmo trutta m. fario ), in European headwater streams. We compared genetic differentiation and diversity with productivity and ecological habitat features of both species in nine different European streams from the drainage systems of the Danube, Elbe, Weser, Tuuloma, Kemijoki and Aulne. Genetic differentiation was more pronounced in pearl mussel than in brown trout, although the drainage-specific patterns were generally similar. Genetic diversity of host and parasite was negatively correlated. The most oligotrophic, postglacially colonized areas represented genetic diversity hotspots with high conservation priority for pearl mussels, whereas their host fish displayed low diversity in these areas. This pattern can be explained by differences in the ecological niches and in the life-history strategies of both species. These results question the effectiveness of single-species approaches in the conservation of genetic aquatic resources and suggest that genetic information from species with different life-history strategies, such as invertebrates and fish, should be considered simultaneously for geographical conservation prioritization in stream ecosystems.     

Biogeography and conservation of freshwater mussels (Bivalvia: Unionidae) in Texas: patterns of diversity and threats

Aim Geographic patterns of species distributions and the factors contributing to species endangerment are necessary for the development of integrative conservation strategies. Freshwater mussels Unionidae have among the highest levels of imperilment recorded in North America. This paper describes the biogeography and diversity of Unionidae along climate and habitat gradients in Texas, evaluates human impact, and identifies the hot spots of diversity and endemism that should be targeted for conservation. Location Texas, North America. Methods Unionids were surveyed in all major Texas river basins in 2003–2009. Multivariate statistics were used to test for differences in environmental parameters and among unionid assemblages in different bioprovinces, and to determine to what extent the multivariate pattern of species distribution was affected by environmental factors. To estimate human impact, we examined the relationship between human population density and the proportion of rare species, as well with the proportion of historically present species that persist in the watershed. Results Correlation between biotic and environmental similarity matrices indicated concordance in the differences among unionid assemblages and environmental factors that could cause these differences. Lake surface evaporation rate and percentage of forest cover in the watershed were among the most important parameters explaining the differences in unionid assemblages. Human population density was negatively correlated with the proportion of rare species. The proportion of species found live relative to the total number of live and relic species found in our surveys and to the number of historically known species decreased with the increase in human population density. Main conclusions Climate, landscape, geology, and land use type were important factors influencing unionid distribution patterns among biotic provinces. Increased human population density was associated with the loss of rare species over several decades, but this loss was not recognized because of a lack of assessing the conservation status of unionids.     

Freshwater mussel conservation: A global horizon scan of emerging threats and opportunities

We identified 14 emerging and poorly understood threats and opportunities for addressing the global conservation of freshwater mussels over the next decade. A panel of 17 researchers and stakeholders from six continents submitted a total of 56 topics that were ranked and prioritized using a consensus-building Delphi technique. Our 14 priority topics fell into five broad themes (autecology, population dynamics, global stressors, global diversity, and ecosystem services) and included understanding diets throughout mussel life history; identifying the drivers of population declines; defining metrics for quantifying mussel health; assessing the role of predators, parasites, and disease; informed guidance on the risks and opportunities for captive breeding and translocations; the loss of mussel–fish co-evolutionary relationships; assessing the effects of increasing surface water changes; understanding the effects of sand and aggregate mining; understanding the effects of drug pollution and other emerging contaminants such as nanomaterials; appreciating the threats and opportunities arising from river restoration; conserving understudied hotspots by building local capacity through the principles of decolonization; identifying appropriate taxonomic units for conservation; improved quantification of the ecosystem services provided by mussels; and understanding how many mussels are enough to provide these services. Solutions for addressing the topics ranged from ecological studies to technological advances and socio-political engagement. Prioritization of our topics can help to drive a proactive approach to the conservation of this declining group which provides a multitude of important ecosystem services.     

昆虫多样性的保护现状与趋势

昆虫是自然界中种类最多的动物,在生态系统中具有重要的作用,但是昆虫在生物多样性保护中没有受到应有的重视.多个实例证明,很多昆虫种类处在数量下降甚至绝灭的状态.究其原因,人类的认识不足是导致昆虫多样性保护未受重视的主要原因,栖息地破坏是昆虫濒危的主要原因.由于昆虫生活史的特殊性,其保护策略与大型动物的保护有很大不同.昆虫多样性的保护可以与人类活动共存.     

The Mediterranean monk seal Monachus monachus: status,biology, threats,and conservation priorities

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Freshwater protozoa: biodiversity and ecological function

The purpose of this article is to pull together various elements from current knowledge regarding the natural history of free-living protozoa in fresh waters. We define their functional role, set the likely limits of biodiversity, and explore how the two may be related. Protozoa are unicellular, phagotrophic organisms, and 16 phyla of protists contain free-living freshwater protozoan species. They are the most important grazers of microbes in aquatic environments and the only grazers of any importance in anoxic habitats. In sediments, ciliates are usually the dominant protozoans. Benthic ciliate biomass accounts for slightly less than 10% of total benthic invertebrate biomass, but ciliate production may equal or even exceed invertebrate production. Freshwater protozoan species are probably ubiquitous, although many may persist locally for long periods in a cryptic state – as potential rather than active biodiversity. As protozoa are among the largest and most complex of micro-organisms, it follows that bacteria and all other smaller, more numerous microbes are also ubiquitous. The number of protozoan species recorded in local surveys (232) is about 10% of the estimated global species richness (2390). The 'seedbank of protozoan (and microbial) species ensures that local microbial diversity is never so impoverished that it cannot play its full part in ecosystem functions such as carbon fixation and nutrient cycling.     

Epiphytic bryophyte diversity and range distributions along an elevational gradient in Marojejy,Madagascar

Describing spatial variation in species richness and understanding its links to ecological mechanisms are complementary approaches for explaining geographical patterns of richness. The study of elevational gradients holds enormous potential for understanding the factors underlying global diversity. This paper investigates the pattern of species richness and range-size distribution of epiphytic bryophytes along an elevational gradient in Marojejy National Park, northeast Madagascar. The main objectives are to describe bryophyte species composition and endemism in Marojejy National Park, to describe the species richness and distribution patterns of epiphytic bryophytes along an elevational gradient from 250 m to 2050 m and to evaluate the explanatory value of environmental variables for the observed patterns. Bryophyte samples were collected following a nested design with four hierarchical levels: elevational belts, plots, quadrats, and microplots. In total, 254 epiphytic bryophyte species were recorded, comprising 157 liverworts and 97 mosses. Twenty-three of these are endemic to Madagascar. Species richness exhibits a hump-shaped pattern along the elevational gradient, peaking at 1,250 m. Eighty-seven percent of the total recorded species have a range distribution lower than 1,000 m, at which point 36% are restricted to these single elevations. Our results suggest that mean temperature, relative humidity, and vapor pressure deficit play important roles in shaping the richness pattern observed in this study. While the liverwort richness pattern did not correlate to vapor pressure deficit and responded only weakly to relative humidity, the richness pattern shown by mosses correlates well with mean temperature, relative humidity, and vapor pressure deficit.     

Gondwana Link: connecting people,landscapes, and livelihoods across southwestern Australia

The Gondwana Link (GL) program spans some 1,000 km and includes organizations, businesses, and individuals working to improve ecological function across the most intact large areas of habitat remaining in southwestern Australia (SWA). Noncompetitive leadership plus a focus on tangible achievement have been critical to providing the cohesion and initial momentum needed to support and inspire increased effort from those involved. Ongoing success rests on the responses of people working together, having respect for the integrity of the collective effort and for the specific roles of others across differing but complementary roles. Significant achievements have been secured, with progress in scientific knowledge generally following initial implementation of key actions. Lasting improvements in ecological health and resilience will only occur through larger‐scale actions, which require more effort and time. The GL program has been an important initiative in strengthening the awareness of the distinctive ecological systems across SWA and the intertwined characteristics of resilience and fragility that characterize the region and its people. It has also had a role in inspiring and informing growth in large‐scale connectivity programs nationally and internationally.     

Declining freshwater mussel diversity in the middle and lower reaches of the Xin River Basin: Threat and conservation

Freshwater mussels provide important functions and services for aquatic ecosystems, but populations of many species have been extirpated. Information on biodiversity plays an important role in the conservation and management of freshwater mussels. The Xin River Basin is a biodiversity hotspot for freshwater mussels in China, with more than 43 species known, but populations of which are decreasing. Here, we quantify the diversity of freshwater mussels in the middle and lower reaches of the Xin River Basin and study the correlation of habitat characteristics and freshwater mussel diversity. Compared to the historical period, the number of species, density, and biomass of freshwater mussels decreased 33%, 83%, and 82% in the current period, respectively. Fifty two percent of recorded species were empty shells, and 14 native freshwater mussels were not found in the study area. Four species are currently listed as vulnerable species using IUCN criteria and their global status. The assemblage structure of freshwater mussels exhibits significant spatial differences, and there was a correlation with substrate and physicochemical parameters. The main tributary of the Xin River with higher freshwater mussel diversity should be established as one large protected area because the nestedness component was the main pattern of beta diversity. These results indicated freshwater mussel diversity was declining rapidly, which can help focus conservation effort for freshwater mussel biodiversity.     

Checklist of the freshwater fishes of Armenia,Azerbaijan and Georgia

We present a critical checklist of freshwater fish species found so far in the countries of Armenia, Azerbaijan and Georgia. In total 119 freshwater fishes are recorded. There are 40, 86 and 96 species currently known for Armenia, Azerbaijan and Georgia respectively. From these 119 species, seven are endemic and seven species are alien. From the alien species, only three (Carassius gibelio, Gambusia holbrooki and Pseudorasbora parva) can be considered as widespread and invasive. There are four species (Gasterosteus aculeatus, Gobio artvinicus, Perca fluviatilis and Salmo gegarkuni) that are translocated within the region. Seven species are confirmed or recorded for the first time including G. artvinicus and Oxynoemacheilus veyselorum for Armenia, Azerbaijan and Georgia, Capoeta kaput and Rhinogobius lindbergi for Azerbaijan and Georgia, Capoeta razii for Azebaijan, Oxynoemacheilus cemali and Squalius agdamicus for Georgia. In this checklist, Acipenser colchicus is treated as a synonym of Acipenser persicus. Sand smelts of the Black and Caspian Sea basin are identified as Atherina caspia and Clupeonella caspia is treated as a synonym of Clupeonella cultriventris. Coregonus sevanicus is listed as Coregonus sp. until the situation of Sevan whitefish is better understood. Capoeta sevangi and Capoeta ekmekciae are synonyms of Capoeta capoeta. The fish often identified as Capoeta capoeta gracilis from rivers south of the Kura most likely belong to C. razii. The Black and Caspian Sea Rutilus populations are treated as conspecific, therefore R. kutum is a junior synonym of R. frisii. Oxynoemacheilus veyseli is valid as O. veyselorum. We list the alien Rhinogobius species as R. lindbergi, however the name is provisional and needs further confirmation. All Squalius species from the Kura River drainage are identified as S. agdamicus, however in the Aras, it is replaced by S. turcicus. Squalius orientalis is treated as a valid species restricted to the eastern Black Sea basin. The four forms of Lake Sevan trout (Salmo ischchan, S. gegarkuni, S. danilewskii and S. aestivalis) are treated as valid species, two of them (S. ischchan and S. danilewskii) are extinct. Rutilus sojuchbulagi from Azerbaijan is also extinct.     

Tree diversity and distribution in undisturbed and human-impacted sites of tropical wet evergreen forest in southern Western Ghats, India

The composition, abundance, population structure and distribution patterns of all woody species ( 30 cm gbh) were investigated in an undisturbed and two adjacent human-impacted sites of a tropical wet evergreen forest in Kalakad National Park, Western Ghats, south India. Three 1-ha plots were established, one each in (i) an undisturbed site (named site UD), (ii) in a site selectively felled 35 years ago (site SF – small stems felled leaving the large trees (as shade) for developing it into a cardamom estate, on the failure of which the site was abandoned) and (iii) a frequently disturbed site (site FD – round woods logged for use in ovens for curing cardamom). These sites are 1 to 3 km apart in the same wet evergreen forest. In the three study plots a total of 2150 stems (mean density 716 ha^–1) covering 122 species in 89 genera and 41 families were enumerated. Species richness was greatest (85 species ha^–1) in the undisturbed site UD, intermediate (83) in SF and lowest (80) in FD. Tree density was greatest (855 stems ha^–1) in site SF, intermediate (720) in UD and lowest (575) in FD. The forest stand was exceptionally voluminous in site UD (basal area 94.64 m² ha^–1), intermediate (66.9 m²) in SF and least (61.7 m²) in FD, due to tree removal for fuel in the latter sites. Species composition and abundance patterns markedly varied between the three sites. In UD and SF, primary forest species (Cryptocarya bourdillonii , Cullenia exarillata Myristica dactyloides etc.) occurred in greater density. In FD heliophilic secondary forest species (Elaeocarpus venustus, Litsea wightiana, Viburnum punctatum and Vitex altissima) were abundant, while these were absent in UD and SF. The species–area curve did not reach an asymptote in any of the sites on the 1-ha scale. The stand population structure was clearly reverse J shaped in UD and SF, while small stems were 2- to 3-fold fewer in FD. Most trees exhibited clumped distribution of individuals on the 1-ha scale. Variation in the kind and richness of species and their abundance is related to human interference and the need for forest conservation is emphasized.     

Priority areas of intraspecific diversity: Larzac, a global hotspot for facultative paedomorphosis in amphibians

Although the designation of biodiversity hotspots is a valuable tool to improve conservation efforts, this is a concept primarily based on species diversity. In consequence, another component of biodiversity, adaptive variation, is often ignored in conservation and to my knowledge no attempt has been made to identify hotspots of remarkable intraspecific patterns. My aim was to focus on the process of facultative paedomorphosis (i.e. the retention of larval traits such as gills in adult variants), a rare developmental pathway. One hundred and seventy-four ponds were inventoried in Larzac (France) to determine the distribution and abundance of paedomorphic palmate newts Triturus helveticus (Amphibia, Caudata) and to compare these results with the current distribution of paedomorphs in this and other species. During this study, paedomorphic newts were found in 46 ponds, 32 of which were described here for the first time. Seventy-nine per cent of known paedomorphic populations of this species were found there, whereas this area covers only 0.5% of the distribution area of the species. This represents the highest known density of facultatively paedomorphic populations, all species being considered. Because these populations face a high threat of disappearance, Larzac should be designated as an intraspecific biodiversity hotspot in order to protect adaptive intraspecific variation. Future conservation-oriented work should focus not only on species distributions but also on phenotypically diverse but spatially localized variation.