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1.
Successful biodiversity conservation needs to be based on reliable data regarding the distribution and abundance of species. Red Lists summarize the status of rare and declining species. Here we present the first detailed survey (10 m × 10 m resolution) of nationally red-listed bryophytes and lichens at stand level in boreal forests. 30 managed forest production stands in boreal Sweden, soon to be harvested, were surveyed in detail regarding red-listed bryophytes and lichens. On the 180 ha totally investigated, 33 red-listed species were found, representing 35% of all forest red-listed bryophytes and lichens so far recorded from this part of Sweden. The mean number of red-listed species per stand was 10 and varied between 5 and 16. Excluding three species which were so common that, given the time-limit, it was not possible to record all of their occurrences, there were on average 6 number of observations ha −1. The presence and density exceed those earlier found in ‘key habitats’, defined as hot-spots for red-listed species. Almost all observations were made on trees, with 48% on living trees and 52% on dead. Altitude, area and stem volume explained 67% of the red-list species density. The results highlight the importance of unprotected areas for rare and declining species and point to a hitherto unacknowledged high biodiversity value of mature managed boreal forest stands, shaped by a less intense forestry than today's. It also raises questions regarding the use of red-listed species to identify areas of importance to biodiversity. Objective and systematic surveys of red-listed species in the forest landscape, including younger stands, are urgent.Der erfolgreiche Schutz der Biodiversität muss auf verlässlichen Daten über die Verbreitung und Abundanz der Arten basieren. Rote Listen fassen den Status seltener und abnehmender Arten zusammen. Hier präsentieren wir die erste detaillierte Erfassung (10 m × 10 m Auflösung) von Bryophyten und Flechten der nationalen Rote Liste auf Bestandsniveau in borealen Wäldern. Im borealen Schweden wurden in 30 bewirtschafteten Produktionswälder, die bald geerntet werden sollen, die Bryophyten und Flechten der Roten Liste im Detail erfasst. Auf den insgesamt untersuchten 180 ha wurden 33 Arten der Roten Liste gefunden, die 35% aller Wald-Bryophyten und-Flechten der Roten Liste repräsentieren, die bisher in diesem Teil Schwedens erfasst wurden. Die mittlere Anzahl derRote-Liste-Arten pro Bestand war 10 und variierte zwischen 5 und 16. Unter Ausschluss von drei Arten, die so gewöhnlich waren, dass es bei dem gegebenen Zeitlimit nicht möglich war alle ihre Vorkommen zu erfassen, gab es im Durchschnitt 6 Beobachtungen ha −1. Vorkommen und Dichten übertrafen die früher in “Schlüsselhabitaten” gefundenen, die als ‘hot spots’ bezeichnet werden. Fast alle Beobachtungen wurden auf Bäumen gemacht, mit 48% auf lebenden und 52% auf toten Bäumen. Die Höhe, das Gebiet und das Stammvolumen erklärten 67% der Dichte der Rote-Liste-Arten. Die Ergebnisse heben die Wichtigkeit nicht-geschützter Gebiete für seltene und abnehmende Arten hervor und weisen auf einen bisher nicht wahrgenommenen hohen Biodiversitätswert von alten bewirtschafteten borealen Waldbeständen hin, die von einer weniger intensiven Forstwirtschaft als der heutigen geformt wurden. Es stellen sich ebenso Fragen, die die Verwendung der Rote-Liste-Arten betreffen, um für die Biodiversität wichtige Gebiete zu identifizieren. Objektive und systematische Erfassungen der Rote-Liste-Arten in Waldlandschaften inklusive der jüngeren Bestände sind dringend. 相似文献
2.
The distribution of lichens in lowland deciduous and evergreen forests in Thailand is used to interpret recent changes in the distribution of these forests. The role of fire in changing the forest structure, microclimate and species content is discussed. Characteristic corticolous lichen communities of dry deciduous and moist evergreen forests are described, as well as changes in the composition of the flora following fire events. Where frequent fires have altered the forest rates of change in forest type are suggested using lichen data from randomly selected trees in forest plots, and growth rates of sampled species in quadrats. The disjunct nature of the lichen floras in lowland deciduous and evergreen forests is discussed, their origin and use in interpreting changes in forest types in monsoon climates over long periods of time. 相似文献
3.
Guaiacum sanctum and Guaiacum coulteri are long‐lived Mesoamerican timber tree species heavily exploited throughout their range and considered to be at risk of extinction. Both species are included on the IUCN Red List and on CITES Appendix II, but there has been no formal assessment of the conservation status of either species. We used ecological niche modeling and rapid assessments of local density and population size structure to provide such evaluations. For the year 2000, we estimated geographic range sizes for G. sanctum and G. coulteri of 95,422 and 130,973 km 2, respectively. The main core remaining habitat for G. sanctum occurs in Campeche State (Yucatan Peninsula), where populations exhibit high adult abundance and profuse regeneration. Several areas along the Mexican Pacific coast remain with suitable habitat for G. coulteri. Guaiacum coulteri is at greater risk as only 1.3 percent of its current habitat is protected, which contrasts with the 13.2 percent of current habitat protected for G. sanctum. We projected that available habitat for G. sanctum and G. coulteri will decline by a further 30–50 percent by 2020 if estimated habitat loss rates continue. We suggest that under the IUCN criteria, the conservation status of G. sanctum and G. coulteri should be updated to near threatened and vulnerable, respectively. Additionally, we conclude that the amount of protected habitat needs to be increased to safeguard both species. Our study provides a quantitative basis for updating the conservation status of both species and illustrates an assessment framework that could be applied to other threatened tree species. 相似文献
4.
根据世界自然保护联盟 (IUCN) 1994年前制订的《IUCN红色名录》和 1994年IUCN理事会第 4 0次会议上通过的《世界物种红色名录濒危等级》(IUCNRedListCatagories) ,针对我国 1989年颁布的《国家重点保护野生动物保护名录》和 2 0 0 0年国家林业局颁布的《国家保护的有益或者有重要经济、科学价值的陆生野生动物名录》中有关蝴蝶的部分 ,简述制订时的历史背景 ,就其中涉及海南分布的蝴蝶保护种划分的科学依据进行了探讨 ;建议今后蝴蝶保护名录修订时应将栖息地的保护状况列为评估濒危状况的首要依据 ,使保护名录更附合客观事实并有利于保护的可操作性 ;提出保护生物资源的最终目的是在条件成熟时对它们进行利用 ,如果可持续性利用的生物资源不加以利用 ,就是对资源的浪费 ;在利用中需引入高新技术、开拓创新 ,以提高利用效益 ,进而提升资源保护的管理水平。 相似文献
5.
Questions Vegetation resurveys, both single studies and meta-analyses, have predominantly been based on vascular plant data while bryophytes and lichens have largely been neglected. Our study aims to fill this gap and addresses the following research questions: has the overall species richness of terricolous bryophytes and lichens in forests changed over time? Which are the winners and losers among single species and ecological species groups? Do the results give a signal of the impact of nutrient enrichment, of changes in the light regime and of climate change? Location Deciduous and coniferous forests in Germany. Methods We compiled 35 single resurvey data sets, including 1096 plots in total (each sampled twice). The time interval between initial surveys and resurveys ranged from 10 to 65 years. The differences between old and new plots were analysed with respect to the frequency of single species, total species richness, and the absolute and relative numbers of taxa in the species groups. Trend scores of species were related to ecological indicator values to identify the main environmental drivers behind the observed changes. Results Total species richness did not systematically change, while pleurocarpous mosses had increased at the expense of acrocarpous mosses and, in coniferous forests, of lichens. Weak changes were generally observed in deciduous forests on base-rich soils. In coniferous forests and in deciduous forests on acid soils, species with high nitrogen demand and high shade tolerance had increased, whereas those being typical for more infertile and open forest sites had decreased. There were trends towards a larger share of taxa with a more oceanic distribution. Conclusions The changes in the vegetation of terricolous bryophytes and lichens in the studied forests indicate nutrient enrichment and increasingly shady conditions in forests on acid soils, likely caused by nitrogen deposition and shrub layer closure. 相似文献
6.
The main goal of this study is to document the biogeographical patterns, current status and conservation of 24 species of
vascular plants in Mexico, all of them recorded in some risk category in the Mexican official publication named ‘Norma Oficial
Mexicana 059’ (NOM-059) and some of them in the IUCN red lists (the World Conservation Union) and CITES (Convention on International
Trade in Endangered Species); many of these species are linked to Mexican cloud forests and other temperate vegetation types.
Distribution maps of these 24 species were generated with information obtained from specialized literature, herbarium specimens,
institutional databases, and field work; with this information, the patterns of richness and endemism of these species were
obtained. For this, the Mexican territory was divided using a grid system based on a chart index (scale 1:50,000 system composed
by grids of 15' × 20'). Also, we up to date the knowledge of these species and their populations and current habitats, and
evaluate their geographic distribution in relation to the current Mexican National Parks and Reserves System and Mexican Priority
Regions for Conservation. We also discuss some changes of categories in the NOM-059 and suggest the urgent incorporation of
some of the species in the recent IUCN Red Data List of Threatened Species (2003). Most of the species studied require special
policies for their conservation due to problems that affect their natural populations; also we consider that these taxa are
underrepresented in the current Mexican System of Natural Protected Areas, especially those with restricted distributions. 相似文献
7.
Aim In light of the current biodiversity crisis, there is a need to identify and protect species at greatest risk of extinction. Ecological theory and global-scale analyses of bird and mammal faunas suggest that small-bodied species are less vulnerable to extinction, yet this hypothesis remains untested for the largest group of vertebrates, fish. Here, we compare body-size distributions of freshwater and marine fishes under different levels of global extinction risk (i.e. listed as vulnerable, endangered or critically endangered according to the IUCN Red List of Threatened Species ) from different major sources of threat (habitat loss/degradation, human harvesting, invasive species and pollution). Location Global, freshwater and marine. Methods We collated maximum body length data for 22,800 freshwater and marine fishes and compared body-size frequency distributions after controlling for phylogeny. Results We found that large-bodied marine fishes are under greater threat of global extinction, whereas both small- and large-bodied freshwater species are more likely to be at risk. Our results support the notion that commercial fishing activities disproportionately threaten large-bodied marine and freshwater species, whereas habitat degradation and loss threaten smaller-bodied marine fishes. Main conclusions Our study provides compelling evidence that global fish extinction risk does not universally scale with body size. Given the central role of body size for trophic position and the functioning of food webs, human activities may have strikingly different effects on community organization and food web structure in freshwater and marine systems. 相似文献
8.
Question: Herb‐rich patches are biodiversity hotspots for vascular plants in boreal forests. We ask: Do species occurrences on herb‐rich patches show a non‐random, nested structure?; Does patch size relate to richness of edaphically demanding and red‐listed species?; Does a set of small patches support more edaphically demanding and red‐listed species than a few large patches of the equal area? Location: Eastern Finland (63°04′N, 29°52′E), boreal vegetation zone. Data: Vegetation mapping of 90 herb‐rich sites, varying from 0.05 to 6.93 ha in size and belonging to six different, predetermined forest site types. Results: Using the RANDNEST procedure, only one site type showed a significantly nested pattern, and patch area was not related to “nestedness” in any of the site types. The number of edaphically demanding and red‐listed plant species was positively correlated with a patch size in three forest site types. In all site types, a set of small patches had more edaphically demanding and red‐listed species than did a few large patches of the equal total area. Conclusions: For conservation, it is essential to protect representative sets of different herb‐rich forest site types because flora varies between the site types. Within herb‐rich forest site types, several small areas may support representative species composition. However, successful conservation requires thorough species inventories, because of the high level of heterogeneity between the herb‐rich patches. 相似文献
9.
Preservation of woodland key habitats has become an integral part of biodiversity-oriented forest management in northern Europe.
In Finland, brook-side spruce forests constitute the most important key-habitat type in terms of total area and timber volume.
Our aim was to compare polypore diversity and the occurrence of red-listed species between brook-side key habitats and comparable
sites of managed forest as controls. Furthermore, we assessed the importance of stand structural features to polypore communities,
and contrasted regions with different land-use history. Altogether 69 key habitats and 70 controls were inventoried in four
regions across southern Finland. A total of 28,023 surveyed dead-wood units had 3,307 occurrences of 114 species of which
25 species were red-listed. Key habitats hosted on average 28% (about two species) more polypore species (mainly deciduous-specialists)
than controls because of a larger average volume of dead wood and a higher proportion of dead deciduous wood. However, the
average number of red-listed species was low and did not differ between the two forest categories. We detected a landscape
effect connected with the intensity and length of forest management history, with the highest numbers of all and red-listed
species per site in eastern Finland. Volume and diversity of dead wood were the most important variables explaining variation
in species richness. Presently, key habitats in managed forests appear to contribute only little to the conservation of red-listed
polypore species. 相似文献
10.
We review the conservation status and threats to the endemic vascular flora of the Cape Verde islands, mostly based on the past two decades of collecting, literature review and herbarium specimens. The application of IUCN Red List criteria and categories using RAMAS software reveals that 78% of the endemic plants are threatened (29.3% Critically Endangered, 41.3% Endangered, 7.6% Vulnerable). Most of these endemics have a limited geographical range, and half of them have Areas of Occupancy and Extents of Occurrence of < 20 and 200 km 2, respectively. Our data show that, over the last two decades, the Cape Verde vascular plants have become more threatened and their conservation status has declined, mostly as a consequence of the increase in exotic species, habitat degradation and human disturbance. This paper presents the first comprehensive IUCN Red List data review for the plants endemic to Cape Verde, thus providing an important step towards the recognition and conservation of its threatened endemic flora at the national and global level. It also fills a knowledge gap, as it represents the first thorough assessment of the conservation status of the entire endemic flora of a Macaronesian archipelago. 相似文献
11.
For the first time the well known drought stress hormone abscisic acid, which is involved in regulating processes increasing desiccation tolerance in many plant systems, was analysed in lichens. ABA was detected in all 26 species investigated. In contrast to higher plants and liverworts, the ABA content increased after hydration of air dry lichen thalli and decreased in desiccating lichen material. Experiments with Baeomyces rufus (Huds.) Rebent indicated that the mycobiont might be the major site of ABA biosynthesis. After incubation of hydrated lichen thalli with radioactive ABA for up to 72 h no metabolism to phaseic acid and dihydrophaseic acid could be detected. Fluctuations of internal ABA might be a result of ABA release to the external medium. 相似文献
12.
Summary Intense pressures on the use and management of land underscore the need for reliable and up-to-date information on the status of native species. The outcomes of the most recent plant population surveys commissioned by agencies are generally limited by faults or omissions in survey design. There is little guidance on how to design and implement field surveys of plant populations in ways that address the most pertinent gaps in our current knowledge and provide answers of known reliability. In this paper, I used the International Union for the Conservation of Nature (IUCN) Red List criteria as a framework to define the data required from surveys to assess the conservation status of potentially threatened species. The criteria address the location and geographical range of extant populations, aspects of species' life history, the size and structure of extant populations and rates of change in abundance and range. I have described survey designs and sampling techniques for estimating these parameters. Choices of appropriate methods that consider trade-offs between desired levels of precision and rigour and sampling effort are illustrated using surveys of 13 Tasmanian Epacris species as examples. Key elements of the approach are: (i) systematic approaches to field searches and recording both positive and negative search outcomes; (ii) construction and testing of intuitive or quantitative distribution models in an explicit experimental framework; (iii) rigorous cost-effective sampling designs, systematic field methodologies and simple analytical techniques to estimate both the magnitude and uncertainty of distribution and abundance; (iv) assessment of the merits and limitations of alternative sampling options; and (v) inference of changes in distribution and abundance by judicious use of historical data and field evidence of recent population processes. 相似文献
13.
The City of Cape Town (City) covers 2460 km 2 in the southwestern corner of the Cape Floristic Region biodiversity hotspot. Established in 1654, by 1700 there were no animals larger than 50 kg within 200 km of the City. However, apart from an appreciation that timber and firewood were becoming scarce, it was only in the 1930s that the first farm near Cape Point was set aside for conservation. Table Mountain was declared a National Monument in 1958, while it was largely covered by pine and gum plantations. Conservation of the montane areas thereafter expanded, whereas the lowlands were largely ignored, except for a few bird sanctuaries. Only in 1982 was the plight of the lowlands highlighted. Although ad hoc conservation planning was undertaken subsequently, 1997 saw the first priority categorization and conservation plan. The current situation is perilous: a huge effort will be required to meet basic conservation targets for the lowland vegetation types and threatened species. Local and international partners and funders will be key to achieving this. In eight of the City's 19 national vegetation types the minimum conservation targets are not achievable. Of the 3250 plant species estimated to occur in the City, 13 are extinct and 319 are threatened according to the IUCN Red List: this is 18% of the threatened Red List species in South Africa. Now for the first time, implementation is being attempted holistically across the metropole with discussion between internal City and external stakeholders to implement the conservation plan. However, the interim plans towards achieving this — that 60% of the unproclaimed target is secured by 2014, requires that over 40 km 2 be conserved per annum. This leaves 340 km 2 that should be secured by 2020 when projections from City spatial growth indicate that the last critical remnants will be urbanized. 相似文献
14.
Background: Oceanic hazelwoods in western Scotland are hypothesised to be unmanaged post-glacial relicts, representing an unusual type of old-growth forest habitat in Europe. They are characterised by an exceptionally high epiphytic diversity, including their status as ‘hotspots’ for indicators of woodland ecological continuity. Aims: The aim of this study was to evaluate the effects of climate, pollution and management on the occurrence of epiphytic lichens and bryophytes on Corylus avellana. Methods: Thirteen hazelwood study sites were systematically sampled along a climate, pollution and management gradient in Britain. Epiphyte composition and richness were examined in a strict hierarchical framework, and compared against site-, stool- and stem-scale environmental predictors. Results: The study showed that along the gradient from ‘clean-air’ relict sites to ‘polluted’ coppiced sites: (i) epiphytic local stem-scale diversity declined, (ii) there was a loss of late-successional species including foliose cyano- and tripartite lichens and bryophytes and (iii) stem sizes were reduced, providing a further limit to the accumulation of species richness within a site. Conclusions: Relict hazelwoods in western Scotland are confirmed as an example of the most intact epiphyte communities. In particular, we show that the transition to coppicing can be clearly linked to ecological processes causing species loss. 相似文献
15.
We examined the diversity of vascular plants, butterflies, grasshoppers, gastropods and carabid beetles in three calcareous grasslands in the northwestern Swiss Jura mountains, a habitat type that has decreased dramatically during the recent decades. As many as 58 species (ca 22%) of the 266 collected are listed as threatened in northern Switzerland. The number of threatened species ranged from 27 to 49 per site, and 26 species occurred in only one of the three grasslands. The species richness of butterflies and vascular plants correlated positively among the grasslands, while the species richness of other groups did not covary. An index of complementarity indicated that the species compositions (including non-threatened species, and spiders and oribatid mites) of the groups varied greatly among the grasslands. In addition, herbivorous groups were more widely distributed than predators among the three grasslands. Due to this variation in species composition none of the three sites c an substitute for the others, if the biodiversity of these grasslands is to be maintained. Furthermore, the taxonomic groups studied are poor indicators of each others' diversity. Consequently, we support the shopping basket approach to conservation evaluation, i.e. measuring species richness, species composition and complementarity of several groups instead of just one. 相似文献
16.
The long history of human influence on northern temperate landscapes has created a mosaic of successional stages, from closed forest to open grassland. Various species thus adapted to different habitats and it is interesting to explore how these differences in species composition among particular successional stages translate into differences at the community level. For this purpose, we surveyed breeding birds in 233 patches of five different habitats covering a gradient from bare ground to forest in 29 abandoned military training sites scattered throughout the Czech Republic. Linear mixed effects modelling revealed that late-successional habitats (dense scrubland and forest) were the most species-rich, whereas early-successional stages hosted bird communities with the highest habitat specialization and threat level. These results suggest that the habitats of late-successional stages are important for the maintenance of high bird species richness, but that early-successional habitats are essential for highly specialized and threatened bird species. Given the highly adverse impacts of agricultural intensification and land abandonment on open habitats, it is necessary to promote factors creating initial successional stages suitable for specialized and threatened species. 相似文献
17.
This study reports on 230 infrageneric lichenized and lichenicolous taxa from Barla Mountain, Isparta, Turkey and assesses the ecological features of the area using the distribution of the lichens in the region and their poleophoby and solar irradiation ecological indicator values. One lichenized fungus, Protoblastenia terricola, and one lichenicolous fungus, Zwackhiomyces dispersus, are recorded as new in Turkey and 194 taxa are reported for the first time from Barla Mountain. After this research, number of the lichenized and lichenicolous fungi taxa of Barla Mountain rose to 241. Based on assessments using the ecological indicator values, the area is dominated by natural or semi-natural and well-preserved habitats. 相似文献
18.
Abstract Environmental disturbance and condition are complex concepts to define and measure in forested landscapes. The highly fragmented Afrotemperate forests in South Africa are under increasing pressure from the agricultural matrix and resource harvesting. Rapid assessment of forest condition and disturbance would aid their conservation management. The terrestrial amphipod, Talitriator africana, dominates the decomposer guild of Afrotemperate forests and has been previously identified as a potential indicator of forest condition. Using four published studies, we further evaluate this species' suitability as an environmental indicator of forest disturbance and condition. Amphipods were consistently more abundant at highly disturbed forest edges compared to less disturbed interiors, and less abundant in deep litter compared to shallow litter. High amphipod numbers in shallow litter was correlated with low predator abundance. Shallow litter may in turn be caused by more efficient breakdown of litter by amphipods at forest edges. Numbers varied considerably between sites and years, but showed a consistent trend of high abundance with increasing forest disturbance. The latter, and the ease with which it can be surveyed and identified, make a compelling case for the use of T. africana as a single‐species environmental indicator of forest disturbance. However, relatively broad tolerances and the difficulty of calibrating the abundance‐disturbance relationship over a wide region limits the indicator value of this species to the local landscape, where disturbance effects vary only in their intensity (as opposed to type) across forests. 相似文献
19.
1. Flow dynamics is a major determinant of riparian plant communities. Therefore, flow regulation may heavily affect riparian ecosystems. Despite the large number of dams worldwide, little specific information is available on the longitudinal impacts of dams on vegetation, for example how far downstream and at what degree of regulation a dam on a river can influence riparian woodlands. 2. We quantified the long‐term responses of riparian trees and shrubs to flow regulation by identifying their lateral distribution and habitat conditions along a boreal river in northern Sweden that has been regulated by a single dam since 1948. The regulation has reduced annual flow fluctuations, this effect being largest at the dam, downstream from which it progressively decreases following the entrance of free‐flowing tributaries. 3. We related changes in the distribution patterns, composition, abundance and richness of tree and shrub species to the degree of regulation along the river downstream from the dam. Regulation has triggered establishment of trees and shrubs closer to the channel, making it possible to measure ecological impacts of flow regulation as differences in vegetation attributes relative to the positions of tree and shrub communities established before and after regulation. 4. Trees and shrubs had migrated towards the mid‐channel along the entire study reach, but the changes were largest immediately downstream of the dam. Shrubs were most impacted by flow regulation in terms of lateral movement, but the effect on trees extended furthest downstream. 5. The species composition of trees progressively returned to its pre‐regulation state with distance downstream, but entrance of free‐flowing tributaries and variation in channel morphology and substratum caused local deviations. Species richness after regulation increased for trees but decreased for shrubs. The changes in species composition and richness of trees and shrubs showed no clear downstream patterns, suggesting that other factors than the degree of regulation were more important in governing life form. 相似文献
20.
Summary Widespread exotic species provide one of the greatest challenges to biodiversity conservation because they often have devastating impacts on native biota but are near impossible to eradicate. The Red Fox ( Vulpes vulpes ) is established across most of mainland Australia, where it has been linked to severe declines and extinctions of a broad suite of native fauna. A targeted approach to reducing the impacts of Foxes on biodiversity was instigated in New South Wales in 2001 under the New South Wales Fox Threat Abatement Plan. It is based on three simple steps. First, explicit priorities for Fox control are established by identifying which native species are at greatest risk from Fox predation and at which sites Fox control for these species is most critical. Second, high-frequency broad-area Fox-control programmes are established across all land tenures at these priority sites. Third, monitoring programmes are established to measure the response of targeted native fauna and Foxes to Fox control. Monitoring helps refine the priorities for control and the methods used over time. This approach provides a model for the strategic control of widespread exotic pests which threaten biodiversity. 相似文献
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