The conservation and status of threatened fishes in southern Africa

The conservation status of 24 threatened freshwater fishes and seven estuarine fishes from southern Africa is discussed against the background of natural and anthropogenic environmental factors. The majority of threatened species are endemic temperate forms with restricted ranges. Major threats include introduced alien fishes and a wide spectrum of environmentally destructive causes. Research on threatened species includes distribution surveys, biological and ecological studies and methods of artificial propagation. Long-term remedies based on ecosystem conservation are also being promoted. The perceptions and attitudes of nature conservation authorities are adjusting to the new challenges offish conservation. The number of threatened fishes in Africa is likely to increase in the face of escalating problems of habitat destruction and degradation.     

Desert fishes: an interdisciplinary approach to endangered species conservation in North America

The habitat degradation and species endangerment that preceded and accompanied the North American environmental movement in the late 1960s and early 1970s found the conservation community ill-prepared. Protective legislation and basic research necessary for structuring recovery efforts did not exist. Desert aquatic communities were among the first to need attention, and an interdisciplinary effort was mounted in an early application of conservation biology. The history and evolution of desert ecosystem preservation are discussed, and case histories are presented that may prove helpful in other parts of the world as habitats are inexorably reduced. The role of the Desert Fishes Council in co-ordinating efforts of research scientists and resource managers to achieve common objectives is emphasized.     

黄河流域淡水鱼类多样性和保护

本文介绍了黄河流域鱼类研究的历史、淡水鱼类的物种组成、整体分布格局、特有性、濒危性, 以及鱼类多样性在黄河上、中、下游等的特点。历史上对于黄河鱼类多样性的研究, 历经了四个阶段, 从最初的零星记录一直到现阶段的深入研究。综合历史记录和野外调查, 已知黄河流域分布的淡水鱼类共计147种, 隶属于12目21科78属, 其中鲤形目种类占据绝对优势。另外, 全流域黄河特有种计有27种, 受危物种24种, 分别占总数的18.37%和16.32%。同中国主要江河相比, 黄河鱼类在高级分类阶元上的多样性较高, 但物种多样性则处在较低水平; 尽管黄河特有鱼类和受危物种比例低于全国平均水平, 但上游特有鱼类和珍稀濒危鱼类的占比很高。目前黄河鱼类多样性大幅降低, 现状调查仅能采获历史记录种类的53.06%。梯级水电开发、水资源过度利用、外来物种、水域污染和过度捕捞都是威胁鱼类多样性的重要因素, 但对各河段和支流的影响不一, 应做出有针对性的保护部署。     

Captive breeding for the conservation of cichlid fishes

Cichlid fishes are by far the largest familial group of endangered vertebrates, especially the haplochromines. This paper concerns the organization and management of captive breeding of haplochromine cichlids. The setting up of a small-scale laboratory programme for the conservation of endangered species is described in terms of funding, staffing, installation and livestock husbandry. Breeding is discussed in the context of the selection of broodstock, basic reproductive biology, rearing, disease, pathological disorders and the arrangements necessary for the transfer and documentation of progeny. There are already indications in Africa and elsewhere that the dramatic decline and demise of cichlid taxa in Lake Victoria will not be an isolated phenomenon. There is no prospect that the captive breeding of cichlids can alone resolve such large-scale problems in fisheries management and ecology, or prevent the loss of taxa in nature. Nevertheless, captive breeding provides conservation options which are otherwise limited or unavailable regarding the saving of individual 'heritage' species, restocking to the wild, fundamental laboratory research and, finally, public education on the grave issue of actual and prospective mass extinctions of cichlids and other rare fishes.     

Phylogeography of the cyprinid Squalius aradensis and implications for conservation of the endemic freshwater fauna of southern Portugal

The Iberian cyprinid fauna, characterized by the presence of numerous endemic species, has suffered from significant habitat degradation. The critically endangered Squalius aradensis is restricted to small drainages of southern Portugal, habitats that typically exhibit a characteristic Mediterranean-type heterogeneous hydrological system throughout the year, including alternation of flooding events during winter and complete drought in large river sections during summer. To assess the effect of historical and recent processes on genetic diversity in S. aradensis we examined within- and among-population variability in cytochrome b and six polymorphic microsatellite loci. Estimates of genetic diversity in time and space through the combined use of traditional Phi-/F-statistics, phylogenetic trees, ordination methods and nested clade analysis indicated significant and congruent structuring among populations. Data suggest that the Arade drainage represent the evolutionary centre of the species, with subsequent allopatric fragmentation across drainages. Factors other than isolation by distance strongly affected the within-drainage genetic differentiation observed in these Mediterranean-type drainages, including recent population expansion from a bottleneck event and restricted gene flow imposed by a long-term barrier (brackish water area). Significant correlation was found between S. aradensis allelic diversity and upstream drainage area. The relevance of findings for conservation issues is discussed in relation to local intermittent hydrological conditions, the highly restricted distribution and the critically endangered status of the species.     

Endemic freshwater finfish of Asia: distribution and conservation status

Freshwater finfish species richness and level of endemism in East, and South and South‐East Asia that included 17 nations were studied using available databases, and included nation‐wise distribution, habitat types, and conservation status. The number of endemic finfish species in the region was 559, belonging to 47 families. Families Cyprinidae and Balitoridae accounted for 43.5% and 16.2% of the total number of endemic species in the region, respectively, followed by Sisoridae (25), Gobiidae (20), Melanotaeniidae (19), and Bagridae (16), and the other 41 families had at least one endemic species. Nation‐wise the most number of endemic freshwater finfish species occur in India (191), followed by China (88), Indonesia (84), and Myanmar (60). In India, the endemic species accounted for 26.4% of the native freshwater fish fauna, followed by South Korea (16.9%), the Philippines, (16.3%) and Myanmar (15.7%). Statistically significant relationships discerned between the number of indigenous and endemic species richness to land area (X_la in 10³ km²) of the nations in the region were, Y_in = 218.961 Ln(X_la) – 843.1 (R² = 0.735; P < 0.001) and Y_e = 28.445 Ln X_la?134.47 (R² = 0.534; P < 0.01), respectively, and between indigenous and endemic species richness was Y_e = 0.079X_n? 1.558 (R² = 0.235; P < 0.05). The overall conservation status of endemic finfish in Asia was satisfactory in that only 92 species were in some state of vulnerability, of which 37 species (6.6%) are endangered or critically endangered. However, the bulk of these species (83.7%) were cave‐ and or lake‐dwelling fish. However, nation‐wise, the endemic freshwater finfish fauna of the Philippines and Sri Lanka, based on the imperilment index, were found to be in a highly vulnerable state. Among river basins, the Mekong Basin had the highest number of endemic species (31.3%). The discrepancies between databases are highlighted and the need to consolidate information among databases is discussed. It is suggested that the Mekong Basin be considered as a biodiversity hotspot, and appropriate management strategies be introduced in this regard.     

A review of conservation status of freshwater fish diversity in China

China harbors a high species diversity of freshwater fishes not shared with any of its neighboring nations. Freshwater fish diversity in the country has been under severe threat from human activities over the past decades, thus conservation freshwater fishes and ecosystems is urgently needed. To accumulate baseline data for guiding protection actions, the third red list assessment of Chinese freshwater fishes was carried out. Among Chinese freshwater fishes assessed, there are 355 at-risk species (22.3% of the total), including 69 ranked as Critically Endangered, 97 as Endangered, and 189 as Vulnerable. Two species are classified as Extinct and one as Regionally Extinct. China's threat level seems to be lower than the known average level found in the IUCN's global assessment of freshwater fishes, but this is an artifact of a high rate of species classified as Data Deficient. Conservation of freshwater fishes is presently facing a grim situation in China. Imperilment of Chinese freshwater fishes is primarily attributed to habitat loss and degradation arising from human perturbations, particularly river damming. Despite the adoption of protected areas setting up, captive breeding and release, and a fishing moratorium, conservation efforts for freshwater fishes are compromised by disproportional attention in China's biodiversity conservation, baseline data deficiency, insufficiently designed protection networks, and inefficient or inadequate implementation of conservation strategies. To achieve the objectives of Chinese freshwater fish conservation, it is proposed to conduct a national-scale survey of fish diversity and reassess their at-risk status, develop systematic conservation planning of freshwater fish diversity and ecosystems, prioritize strategies for protected areas development, perform genetic-based captive breeding for releasing in concert with other protection actions, and implement flexible fishing moratorium strategies in different water bodies.     

Rare British marine fishes-identification and conservation

Methods of recording and categorizing rare British marine fishes and their habitats are described. Information is stored on a database designed for maximum flexibility, cross-referencing, multiple word search and key word search facilities. Examples are given and discussed in relation to species and habitat protection.     

Ecology and conservation status of endemic freshwater crabs in Lake Tanganyika, Africa

Sedimentation resulting from riparian deforestation has a wide range of detrimental effects on aquatic biodiversity, but predicting the full consequences of such disturbances requires an understanding of the ecosystem’s key functional components. We investigated the ecology and response to sedimentation of the diverse, endemic freshwater crabs of Lake Tanganyika, which may occupy important positions in littoral foodwebs. Our surveys revealed crab distribution patterns to be patchy, and that crabs can be locally abundant (0–28 individuals m⁻²). Crab densities decreased with depth and the dry mass of crab assemblages ranged from 0.0 to 117.7 g m⁻². Comparisons among sites revealed significant effects of sedimentation on crab assemblage evenness, but provided no evidence that sedimentation has altered densities, incidence or species richness. The resilience of crabs to sedimentation might be related to their intraspecific dietary breadth. Stable isotope data (δ¹³C and δ¹⁵N) from crabs and their potential food resources indicated differences in trophic roles among endemic crab species. Overall, crabs occupy higher trophic positions than most other invertebrates, and they draw upon both benthic and planktonic energy pathways. The high biomass and top-predator status of some crab species suggests the potential for cascading effects on organisms lower in the food web.     

Threats to the indigenous freshwater fishes of Sri Lanka and remarks on their conservation

Sixty-two freshwater dispersant (26 endemic), 26 saltwater dispersant and 20 exotic fishes have been recorded from Sri Lanka's inland waters. The discovery of nine new species of freshwater fish during the past decade suggests that Sri Lanka's fish fauna is not yet well known and that further discoveries can be expected. All the new species, and almost all the endemic ones, have been recorded from forested areas in the foothills of the southwestern wet zone and the Knuckles hills. The known ranges of many species are exceedingly small; almost all of them are habitat specialists. 25 species have at least two strong habitat preferences (in almost all case, shade being one), though a majority (32 species) have none. Habitat alteration is therefore the greatest threat to their survival.Eight freshwater fish species are considered endangered and a further five, vulnerable. Three species are rare, 18 common and 13 abundant. All but two of the endangered species and all the vulnerable species are endemic in Sri Lanka. Nine species are each restricted to only one drainage basin, and seven have a known range < 50 km². Three species of diadromous gobies known only from small populations are considered vulnerable.Examination of the existing threats suggest that deforestation, the widespread dispersion of exotics, pollution caused by agricultural chemicals and increasing pressure from the food fishery present the greatest threats to fish populations. While the endemic fishes are restricted to or most abundant in the wet zone, the overwhelming extent (> 95%) of Sri Lanka's nature reserve areas are in the dry zone. A programme to maintain self-sustaining captive populations of the endangered species is urgently necessary.     

Quaternary geomorphological and climatic changes associated with the diversification of Iberian freshwater fishes: The case of the genus Cobitis (Cypriniformes,Cobitidae)

We studied the population genetic structure of Cobitis vettonica, an endangered freshwater fish species endemic to the Iberian Peninsula, in order to propose a biogeographic model of the responses of species to the multiple changes that occurred in the Iberian hydrological system during the Quaternary period. We also deciphered the relationship of C. vettonica with its sister species C. paludica, particularly in sympatric areas, and provide genetic information for conservation purposes. To achieve this goal, we analyzed both mitochondrial and nuclear data (the cytochrome b and the nuclear recombination activating 1 genes) and a battery of single‐nucleotide polymorphisms (SNPs) of 248 individuals of C. vettonica or C. paludica from 38 localities, including some sympatric ones, covering the entire distribution area of C. vettonica. We highlight the important role played by the hydrogeomorphological processes and climatic changes that occurred in the Iberian Peninsula during the Quaternary on both the population structure of C. vettonica and its relationship with its sister species C. paludica. Our results support the genetic introgression of populations at the eastern limit of the distribution of C. vettonica. Furthermore, we postulate genetic introgression in sympatric areas. Finally, we propose the establishment or expansion of four Operational Conservation Units (OCUs) for C. vettonica, and highlight the threat faced by its populations due to the low level of genetic diversity detected for some of its populations and genetic introgression with C. paludica, which could eventually displace C. vettonica, resulting in a loss of diversity in this species.     

Rarity and threat relationships in the conservation planning of Iberian flora

We analysed the threatened flora of Iberia (including the Balearic Islands) in order to define and explain factors related to levels of rarity and threat. Conservation measures were derived from the relationships observed. We used a random sample of 59 narrowly distributed plant species from the pool (588 species) of potentially endangered flora. Twelve variables were used to classify species into groups based on a multivariate technique: non-parametric principal component analysis. Our results do not indicate a single management model driven by a single mechanism of rarity. Four classes of rare plants were produced from the statistical algorithm: agamospermic species, plants associated with water, endemics, and range-margin (geographical-limit) plants. Some specific strategies for each of these groups are proposed, allowing further discussion and assessment. The overall pattern in conservation practice of threatened Iberian plants seems to be defined by three of the variables in use: ecological specificity, geographical rarity and rate of threat. None of the biological variables in the sample show particularly strong trends in the data.     

Conservation status of the threatened Iberian Peninsula narrow endemic Antirrhinum lopesianum Rothm. (Scrophulariaceae)

Abstract

Antirrhinum lopesianum Rothm. is a narrow endemic of the Lusitan Duriensean biogeographical sector (central western Spain and north-eastern Portugal). The species is listed as threatened in several Spanish documents, although it does not figure as such in any Portuguese document. This paper provides a detailed study of its distribution, estimates of the sizes of its populations, the threats it faces, and its current conservation status. The total number of individuals thought to exist is only 768, distributed along the valley of the River Duero on the Spanish – Portuguese border (562, 71.2%), and in the Portuguese Sabor River valley (206, 26.8%). The main threat to the species is loss of habitat: about one third of the Iberian populations can be considered threatened; one population containing 37.6% of all these plants (289) is severely threatened. To determine the Area of Occupancy and the Extent of Occurrence, an exhaustive bibliographical survey was carried out, and herbarium specimens deposited in several institutions were revised. It is, therefore, classifiable as Critically Endangered in Portugal and Endangered in Spain.     

Comparative phylogeography of endemic cyprinids in the south-west Iberian Peninsula: evidence for a new ichthyogeographic area

The comparative phylogeography and evolutionary history of three native cyprinid genera, Squalius (subfamily Leuciscinae), Chondrostoma (subfamily Leuciscinae) and Barbus (subgenus Luciobarbus ; subfamily Cyprininae), were examined focusing mainly in the South-Western region of the Iberian Peninsula, where recently described endemic species are present with considerably restricted distribution areas. In order to accomplish that the variation at the complete cytochrome b gene (1140 bp) was analysed for specimens from the South-Western region, and also for representatives of the three genera from all over the Iberian Peninsula. Data indicate different evolutionary histories, with distinct time periods of colonization between the two cyprinid subfamilies in the Iberian Peninsula. Four new Iberian ichthyogeographic areas are accordingly proposed based on congruent phylogeographic and geological evidences: the South-Western, the South-Eastern, the Atlantic and the Mediterranean. Evidence was provided for the older isolation of the South-Western area in the Miocene during the Endorheic Drainages phase, designating a clearly defined and distinct ichthyogeographic area. A new molecular clock calibration is proposed for the subgenus Luciobarbus .     

Arctic marine fishes and their fisheries in light of global change

In light of ocean warming and loss of Arctic sea ice, harvested marine fishes of boreal origin (and their fisheries) move poleward into yet unexploited parts of the Arctic seas. Industrial fisheries, already in place on many Arctic shelves, will radically affect the local fish species as they turn up as unprecedented bycatch. Arctic marine fishes are indispensable to ecosystem structuring and functioning, but they are still beyond credible assessment due to lack of basic biological data. The time for conservation actions is now, and precautionary management practices by the Arctic coastal states are needed to mitigate the impact of industrial fisheries in Arctic waters. We outline four possible conservation actions: scientific credibility, ‘green technology’, legitimate management and overarching coordination.     

山茶科特有珍稀植物圆籽荷的生物学特性及保护生物学研究

圆籽荷是中国特有的单种属稀有植物,历年来对其研究较少。该文对圆籽荷的分布现状,生境进行了调查,对其物候、形态特征、繁殖过程等生物学特性进行了初步研究。