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1.
We analyze the status of the Angel de la Guarda deer mouse (Peromyscus guardia), a species endemic to Mexico, based on our own fieldwork, bibliographic records and information from colleagues. This species, with different subspecies on three islands and a population of an undetermined subspecies on a fourth, was apparently common until the mid-1960s. Currently the species is critically endangered, if not already extinct. One of the subspecies and the undetermined population are presumed extinct. Of the two other subspecies, one is at least in critical condition, and the other at least reduced. The demise of the species can be attributed to the introduction of domestic cats. The case of P. guardia is a good example of the vulnerability of other taxa of endemic rodents on islands in the Gulf of California.  相似文献   

2.
On islands in the Gulf of California, many species and subspecies of rodents are relict species, restricted to the islands, and now considered extinct or verging on extinction. From 1991 to 1999, each island was surveyed and an average of 15 work-nights were spent on each island, for a total of 15,000 trap-nights. A Fourier series was used to estimate population density. Five native taxa are now considered extinct (Chaetodipus baileyi fornicatus, Peromyscus guardia mejiae, P. g. harbinsoni, P. pembertoni, and Neotoma bunkeri). Two species are at risk of extinction (Dipodomys insularis and Neotoma albigula varia). The most probable cause for extinction is the introduction of nonnative species, specifically cats. We believe that the most vulnerable rodent populations of the islands in the Gulf of California to non-native species are Neotoma lepida latirostra on Danzante island and Neotoma lepida abbreviata on San Francisco island, both in the state of Baja California Sur.  相似文献   

3.
In this paper we summarize the current knowledge on earthworm diversity in the central part of the Balkans, in the State of Serbia. Up to now, 71 species and 8 subspecies, belonging to 18 genera, are known from investigated territory. Our aim was to produce a single priority list for earthworm conservation, particularly as the Balkan countries did not have their own Red Lists for earthworms and none of the species had a legally protected status. The list underlines the diversity of earthworms, zoogeographical position as well as category of threat. The analysis based on the IUCN (2001) Red List Categories shows that 17 of 79 taxa are Critically Endangered (5 species are serious Critically Endangered, but 12 species are only suspect for the Critically Endangered category), 9 species are Endangered and 14 species are Vulnerable. Serious candidates for their inclusion in CR category within the IUCN (2001) Red List are: Cernosvitovia biserialis, Dendrobaena kozuvensis, Lumbricus improvisus, Serbiona kosowensis montenegrina and Serbiona serbica. Of all registered earthworms, 34 taxa (43.1%) were identified only as endemic species. Unfortunately, most of the high-priority species are endemic (23 taxa). The position of the Central Balkans contributes to the great biodiversity of earthworms on its territory, but the fact that nearly 36% of its lumbricids are threatened is a strong signal that action is required.  相似文献   

4.
The Baja California Peninsula is home to 85 species of cacti, of which 54 are endemic, highlighting its importance as a cactus diverse region within Mexico. Many species are under threat due to collection pressure and habitat loss, but ensuring maximal protection of cacti species requires a better understanding of diversity patterns. We assessed species richness, endemism, and phylogenetic and morphological diversity using herbarium records and a molecular phylogeny for 82 species of cacti found in the peninsula. The four diversity measures were estimated for the existing nature reserve network and for 314 hexagrids of 726 km2. Using the hexagrid data, we surveyed our results for areas that best complement the current protected cacti diversity in the Baja California Peninsula. Currently, the natural reserve network in Baja shelters an important amount of the cacti diversity (74% of the species, 85.9% of the phylogenetic diversity, 76% of endemics and all the growth forms). While species richness produced several solutions to complement the diversity protected, by identifying priority species (endemic species with high contribution to overall PD) one best solution is reported. Three areas (San Matías, Magdalena and Margarita Islands and El Triunfo), selected using species richness, PD and endemism, best complement the diversity currently protected, increasing species richness to 89%, PD to 94% and endemism to 89%, and should be considered in future conservation plans. Two of these areas could be included within nature reserves already established.  相似文献   

5.
6.
One of the most serious environmental problems is the current acceleration in the rate of species extinction associated with human activities, which is occurring particularly rapidly in freshwaters. Here we examine whether endemic water beetles are effectively protected by existing conservation measures in the Iberian Peninsula and the Balearic Islands, a region of high diversity and intense human pressure. We used an exhaustive database for aquatic beetles in the region to address such issues. Firstly, we identify the most threatened endemic taxa using a categorization system to rank species according to their conservation priority or vulnerability. Of the 120 endemic species of water beetles used in the analysis, only two (Ochthebius ferroi and Ochthebius javieri) were identified as being extremely vulnerable, 71 were highly vulnerable and 46 moderately vulnerable, with only a single species identified as having low vulnerability status. Since no Iberian species of aquatic Coleoptera has legal protection, the only conservation measure available for these species is the extent to which they occur in protected areas. Here we identify distributional hotspots for threatened endemic species, and evaluate the extent to which these are already included in the Natura 2000 network in Spain and Portugal. Despite a high degree of concordance between hotspots and Natura 2000 sites, the distribution of four species falls completely outside the network. The analysis also reveals that Natura 2000 fails to protect saline water bodies, despite their high conservation interest and narrow global distribution. The picture revealed here with water beetles is likely to be similar for others groups of freshwater macroinvertebrates, since Coleoptera are known to be good surrogates of aquatic biodiversity in the region. Finally, the degree of protection provided via Natura 2000, and the utility of red lists are discussed.  相似文献   

7.
The regularities of the development of algal communities in podzolic soils under coniferous forests were studied in areas differing in their technogenic pollution intensity. In the unpolluted soils under spruce forests, 80 alga species of 6 divisions were found; in the soils under the coniferous forests located in the zone exposed to the technogenic pollution, 59 alga species of 5 divisions were found. The algal groups in the soils of the spruce forests included 14–48 taxa. Chlamydomonas gloeogama, C. reinhardtii, Chlorella vulgaris, Klebsormidium nitens, and Stichococcus bacillaris were resistant to different anthropogenic impacts. The results obtained may be used for monitoring of the state of the soil biota in the soils under the boreal forests of protected areas and also in spruce forests exposed to intense aerial technogenic pollution.  相似文献   

8.
A floristic study of vascular flora of ancient olive groves of Apulia (Italy) was carried out from 2009 to 2011. Research was made in the fields and in the ecological infrastructures of four olive groves, located in protected areas: National Park of Gargano, Park of Dune Costiere, State and Marine Natural Reserve of Torre Guaceto and of Le Cesine. Floristic analysis was carried out by Raunkiaer and Braun-Blanquet. Biological forms and chorological types were named according to Raunkiear. Overall, 408 taxa were identified, of which 332 species, 73 subspecies and 3 varieties, belonging to 275 genera and 74 families. A small segment of 18 taxa, out of 408, was considered of conservation interest. For these taxa the topography of the collecting site, plant community, population density, degree of vulnerability and habitats were recorded, according to the Directive 92/43/EEC. Another segment of 111 taxa, out of a total of 408, was considered important for usage, which for the sake of presentation has been divided in five arbitrary categories: food crops, fodder crops, medicinal, aromatic and officinalis, crop wild relatives and edible wild species. For each of these taxa, an attempt to provide relevant information was made. Only two taxa, i.e., Muscari parviflorum and Aegilops uniaristata are common to both segments. The work was carried out within the competence of the LIFE+ CENT.OLI.MED. (LIFE07 NAT/IT/000450) project, with the aim to gather information for improving conservation and management of olive groves of Apulia, as well as of their related wild life.  相似文献   

9.
Based on studies of brown pelicans Pelecanus occidentalis californicus and Heermann's gulls Larus heermanni, disturbances by recreationists, educational groups, local fishermen and scientists alike can be seriously disruptive and damaging to breeding seabirds in the Gulf of California and off the west coast of Baja California. Similar instances have been identified throughout the world—the problem is not difficult to document, but it is difficult to eliminate. The increasing human-seabird contacts on islands in the Gulf of California and along the west coast of Baja California raise serious questions and immediate concern about the continued preservation of nesting colonies of marine birds in those areas. Conservation measures must consider the extreme sensitivity of many seabirds to the inter- and intraspecific behavioural imbalances created by human disturbances. In some cases, total exclusion of humans may be required; in others, limited access might be possible under closely managed conditions at certain times of the year. A symbiotic relationship between seabird conservation, legitimate research and tourism should be the desired goal.  相似文献   

10.
Stenocereus eruca is a postrate columnar cactus whose regeneration seems to occur mainly through clonal propagation. It is a narrow endemic species of the Sonoran desert in Baja California Sur and currently considered as threatened under Mexican legislation. In this paper we describe the demography of ramets in four populations along its distribution range and the demography of genets in one population during a 3-year-study period in order to evaluate its conservation status. We also analyze the relative contribution of sexual reproduction and clonal propagation to population maintenance and provide guidelines for the formulation of conservation programs. Elasticity analyses were used to explore the relative contribution of sexual and clonal recruitment to projected population growth rate (λ). During the three years of study, regeneration occurred only through clonal propagation while sexually derived seedlings were not detected within or outside the permanent plots. Our demographic data showed that the four population of S. eruca are in equilibrium (λ ≈ 1), and elasticity analyses showed that the relative contribution to λ of clonal recruitment was larger than sexual recruitment, at least during the analyzed ecological time scale. Simulations showed that removing sexual recruitment had a minor impact on λ, but the absence of clonal propagation alone was sufficient to keep below unity. We propose the establishment of at least one reserve with adequate protection from human disturbance to conserve S. eruca.  相似文献   

11.
The fish fauna of mountain streams in the Jiri (440 km2) and Seorak (373 km2) National Park areas of South Korea was investigated from September 1998 to May 2001. A total of 5979 fish were collected and classified into 22 families and 60 species from both national parks. At Jiri, 30 species in 12 families of fishes were collected, while at Seorak there were 42 species in 17 families. Zacco temmincki [relative abundance (RA) 47.9%] was dominant at both parks. Subdominant species were Rhynchocypris kumkangensis (RA 10.8%), Zacco platypus (RA 9.4%), and Pungtungia herzi (RA 5.3%). A total of 20 species were found to be Korean endemic species, representing seven families. The relative abundance of Korean endemic species was higher at Seorak (30.5%) than Jiri (18.5%). One exotic species (Oncorhynchus mykiss) and two species translocated outside their native catchments (Hypomesus nipponensis and Coreoperca herzi) were collected. The proportion of Korean endemic freshwater fish species in both parks (33.3%) was higher than the overall proportion on the Korean peninsula (23.6%). Within the 14 South Korean mountain-area national parks as a whole, larger parks tend to have higher fish diversity. We conclude that South Korean national parks are important for conservation of the regional fish fauna, especially for endemic and endangered species. Current threats to conservation of fishes within South Korean national parks are identified and management solutions are suggested.  相似文献   

12.
We studied the patterns of commonness and rarity for one vertebrate (fish) and four freshwater insect taxa (Ephemeroptera, Plecoptera, Trichoptera and Coleoptera) in southwestern France (57,000 km2), and we analysed the relationships between the location of sites and the contribution of commonness and rarity to species richness within a large stream system. Richness patterns in fish and aquatic insects were related to the location of sites within the stream system. The number of common and rare fish species increased from up- to downstream areas as a result of downstream additions of species. The number of common insect species peaked in the intermediate section of the river continuum, whereas rarity increased with decreasing elevation. In all taxa, common species gave a closer approximation to overall patterns of species richness than did rare ones. The biodiversity patterns of river animals emerged from convergence in the distributions of common and rare species (fish), or mostly from the distribution of common species (insects). However, in fish, Ephemeroptera and Plecoptera, the rarer species became almost equally, or more strongly correlated with overall species richness when increasing information along the common-to-rare and rare-to-common sequences. These patterns suggested that rarer species show a similar or stronger affinity, on a species-for-species basis, for high richness areas than do the commoner species. These schemes have implications for biodiversity assessments, as studies using common species richness to target important areas for monitoring or conservation efforts within stream systems will not necessarily identify areas important for rare species, and vice versa.  相似文献   

13.
During 2002, 2004, 2006 and 2008, trips were undertaken in the United States and Canada by members of the Department of Botany, Palacky University in Olomouc (Czech Republic) to record distributions and sample the diversity of wild and weedy Lactuca species. In that period, 16 states in the USA (Arizona, California, Colorado, Idaho, Iowa, Minnesota, Montana, Nevada, New York, North Carolina, Oregon, South Dakota, Utah, Washington, Wisconsin, Wyoming) and two provinces in Canada (Ontario, Quebec) were visited. Seven wild and weedy Lactuca species (L. serriola, L. saligna, L. virosa, L. canadensis, L. biennis, L. floridana, L. ludoviciana), an interspecific hybrid (L. canadensis?×?L. ludoviciana), and an undetermined Lactuca species were recorded, and 343 seed samples were collected from 200 locations. The largest number of wild Lactuca species that we observed was recorded in Iowa, and the largest number of samples was collected in California. The most common habitats of weedy species (L. serriola, L. saligna and L. virosa) were along transport corridors, such as roadsides, road ditches, parking sites and petrol stations, grassy slopes and ruderal places. The most frequent species was L. serriola, an Old World introduction, which we observed in all states and provinces visited, except for New York, and in broad range of elevations (up to 2,358?m a.s.l.). Lactuca saligna was recorded only one time in Salinas, California. Lactuca virosa was found repeatedly in Washington State along the road to the Mt. St. Helens and in Redwoods, California. Native North American taxa (L. canadensis, L. floridana, L. ludoviciana) were recorded only in Iowa. Lactuca biennis was found only in Canada in the southern part of Quebec. Records of diseases and pests showed only occasional occurrences of downy mildew (Bremia lactucae) and powdery mildew (Golovinomyces cichoracearum). Most plant-disease findings were made in Canada. Results of these efforts enrich our knowledge of the distribution, ecogeography and ecobiology of Lactuca species occurring spontaneously in North America. Seed collections (accessions) will be conserved in the working collection of the genebank at Palacky University to support future research in ecogeography, ecobiology, resistance and genetic polymorphisms, and to enrich of germplasm diversity available for lettuce breeding.  相似文献   

14.
Blue-green algae (Òyanobacteria) have been studied in soils of specially protected natural territories of the Cis-Ural and Southern Ural regions. The species composition of the algae has been determined in water and dish cultures with fouling glasses. The investigated soils are characterized by the rich flora of bluegreen algae comprising 79 species and intraspecies taxa. Recreation loads on the territory have resulted in a drop in the species diversity and numbers of algae; their taxonomic structure is becoming simplified. Active development of algae from the Oscillatoriales order assigned to the P-form and to the typical xerophytes (species of the Oscillatoria, Phormidium, and Plectonema genera) has been registered in some anthropogenically disturbed areas.  相似文献   

15.
Pantepui is a biogeographical province composed of a group of approximately 50 tabular mountain summits, or tepuis, in the southeast of Venezuela. This region, also known as Guayana Highlands (GH), lies between 1500 and 3014 m elevation and has an approximate extension of 6000 km2. The summits of the tepuis are characterized by exceptional vascular plant diversity and high endemism. However, it is expected that ongoing global warming will produce upward displacements of summit taxa, which may cause the extinction of certain species due to habitat loss. This study assessed the potential extinction risk of the >600 Pantepui endemic vascular plant species during the 21st century due to global warming, revealing that 30–50% of endemic species would lose their habitat by the end of this century. In light of these results, prioritization of threatened species for conservation purposes became necessary. This was achieved through the calculation of an Environmental Impact Value (EIV) for each species, and a subsequent division of these species into priority categories, which should be used in a chronological sequence to guide decision-making and future research aimed at establishing the most suitable conservation strategies. A number of in situ and ex situ conservation alternatives were discussed. In situ conservation by means of designating protected areas does not appear a viable option because of the upward habitat displacement involved in this case. Conversely, seed banks, living plant collections and managed relocation were suggested in this chronological order to preserve the species studied here.  相似文献   

16.
Widespread and ecologically important, biological soil crusts include those microbial communities living on the surface of the soil and those that live beneath semitranslucent rocks (a.k.a. hypolithic crusts). We examined the distribution, abundance, physiology, and potential soil N contributions of hypolithic, biological crusts in hyperarid ecosystems of the Baja California peninsula and islands in the midriff region of the Gulf of California, Mexico (Sonoran desert). Crusts were limited in distribution to areas with translucent quartz rocks less than 3 cm thick, were not found on areas of islands with seabird guano deposition, but covered as much as 1% (12,750 m2) of the surface area of one island. The percent of available rocks colonized by crusts was similar between the mainland (38%) and islands without seabird guano (26%). Carbon fixation rates in the field, which have not been previously reported, ranged between 0 and 1.23 μmol m−2 s−1, and in the lab ranged between 0.66 and 0.94 μmol m−2 s−1. Evidence of low rates of N fixation was inferred from δ 15N values of crust and soil. Hypolithic crusts were found to have minimal, if any, influence on soil salinity, pH, and , but may represent up to 14% of the biomass of primary producers on these islands and provide C and N to the belowground and possibly aboveground heterotrophic communities where crusts exist. The results of this study suggest a limited but potentially important contribution of hypolithic soil crusts to hyperarid ecosystems.  相似文献   

17.
Mangrove ecosystems are tropical environments that are characterized by the interaction between the land and the sea. As such, this ecosystem is vulnerable to oil spills. Here, we show a culture-independent survey of fungal communities that are found in the sediments of the following two mangroves that are located on the coast of Sao Paulo State (Brazil): (1) an oil-spill-affected mangrove and (2) a nearby unaffected mangrove. Samples were collected from each mangrove forest at three distinct locations (transect from sea to land), and the samples were analyzed by quantitative PCR and internal transcribed spacer (ITS)-based PCR-DGGE analysis. The abundance of fungi was found to be higher in the oil-affected mangrove. Visual observation and correspondence analysis (CA) of the ITS-based PCR-DGGE profiles revealed differences in the fungal communities between the sampled areas. Remarkably, the oil-spilled area was quite distinct from the unaffected sampling areas. On the basis of the ITS sequences, fungi that are associated with the Basidiomycota and Ascomycota taxa were most common and belonged primarily to the genera Epicoccum, Nigrospora, and Cladosporium. Moreover, the Nigrospora fungal species were shown to be sensitive to oil, whereas a group that was described as ??uncultured Basidiomycota?? was found more frequently in oil-contaminated areas. Our results showed an increase in fungal abundance in the oil-polluted mangrove regions, and these data indicated potential fungal candidates for remediation of the oil-affected mangroves.  相似文献   

18.
The forests and highlands along the southern portion of the Nigeria-Cameroon border and on the island of Bioko have long been recognized as being biologically diverse. This region (referred to as the Biafran forests and highlands) is a center of endemism for a wide variety of taxa including, but not limited to, primates, anuran amphibians, birds, freshwater fish, butterflies, dragonflies, and trees. Though these groups have diverse distributions, conservation efforts have to date largely been focused on lowland areas. We conducted a GIS-based analysis of point locality records for three groups characterized by high endemism (primates, anuran amphibians, birds) in order to examine both their spatial and altitudinal distribution throughout the study area. We also evaluated the distribution of existing and potential protected areas relative to highland areas and the distribution of endemics. Our analysis suggests that the existing protected area system provides poor coverage of montane habitats and their associated endemic taxa. Complementarity analysis suggests that, if the protected area network were expanded to include a small number of highland sites, coverage of endemic taxa could be significantly improved. Many of these important highland sites are currently under intense pressure from habitat loss and hunting. If the full range of biodiversity present in the Biafran forests and highlands is to be preserved, new protected areas should be gazetted that take the varied distributions of the regions endemic taxa into account.  相似文献   

19.
Growing urbanization adjacent to aquatic systems may alter water, sediment and benthic community interactions. The ecological effects of urbanization on regional, local and site-specific spatial variations of benthic macrofauna and of sediment and water properties were investigated in relatively pristine rivers and in urban rivers of southern Brazil. The benthic communities were found to be different in urbanized and protected areas. Their predominant responses to environmental conditions were characterized as either a: (i) sensitive species assemblage, formed by polychaetes Nephtys fluviatilis and Heteromastus similis and the crustacean Kalliapseudes schubarti; or a (ii) tolerant species assemblage, formed by the polychaete Laeonereis acuta and by an unidentified oligochaeta Tubificidae. The relationships between fauna and environment differed between protected and urban rivers. In protected areas the fauna distribution was directly related to grain sorting and phaeophytin a in sediments; and to chlorophyll a, dissolved oxygen and phosphorus in water. In urban sites the strongest determinants of fauna distribution were the presence of lead, copper, dissolved phosphorus, chlorophyll a and phaeophytin a in sediments, and suspended particulate matter, dissolved phosphorus, nitrogen, and silicate in water. The comparison of animal-sediment-water interaction in natural and urban areas can be useful in planning environmental impact mitigation strategies for conservation even in rivers and estuaries with non-point sources of pollution.  相似文献   

20.
Aegilops geniculata Roth, a wild relative of wheat (2n = 4x = 28, genome UUMM), is distributed over the Mediterranean basin and nearby areas. The species consists of two subspecies, subsp. geniculata and subsp. gibberosa (Zhuk.) Hammer. The former is distributed over the whole species area and has been genetically analyzed, and the latter is endemic to Spain and North Africa and has not been genetically evaluated. In this study, to clarify the genetic variation and delineation of the two subspecies from a biosystematic viewpoint, morphological variation among 23 accessions of subsp. geniculata and three of subsp. gibberosa and chromosome pairing at meiosis and fertility in their intra- and inter-subspecific F1 hybrids were examined. A principal component analysis based on the 11 spike characteristics clearly divided the 26 accessions into two groups representing the two subspecies. The inter-subspecific F1 hybrids showed significantly lower frequencies of chromosome pairing, significantly higher frequencies of multivalents, and significantly lower fertilities relative to those of the intra-subspecific F1 hybrids. It was concluded that wide-ranging cytogenetic variation is included in subsp. geniculata, that subsp. gibberosa, the intra-subspecific variation of which is small, is morphologically and cytogenetically differentiated from subsp. geniculata beyond the range of the intra-subspecific variation of subsp. geniculata, and that the two subspecies are effectively isolated reproductively by hybrid sterility. The results strongly suggested that western North Africa is one of the important diversity centers of Ae. geniculata, where two subspecies were differentiated in the past and grow together in the present.  相似文献   

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