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1.
Peter B. McQuillan 《Journal of Insect Conservation》2004,8(2-3):209-220
A brief review of the geometrid fauna of the large island of Tasmania and a simple analysis of its conservation status and threats are presented. The fauna comprises 310 species of which Ennominae contribute slightly less than half the total and Larentiinae one third; 23% of the geometrid fauna is endemic at species level. Mixed eucalypt-rainforest is identified as the richest wet forest habitat in geometrid species. Using distribution data at 10 km resolution, the most widespread and most restricted taxa are identified. The conservation status of Lepidoptera living above 800 m is relatively good. However, coastal species and those associated with herb-rich native grasslands are under some pressure from habitat change. Three species of geometrid moths are listed as threatened in Tasmania’s Threatened Species Protection Act 1995 but several others may qualify for listing. 相似文献
2.
Communities containing bolster (hard cushion) plants are widespread in alpine and subalpine treeless plant communities in Tasmania. Numerical analysis of species presence/absence data from 227 quadrats defined thirteen communities, the distributions of which proved strongly related to a southwest to northeast edaphic gradient and altitude. The high altitude communities and those on oligotrophic soils are most likely to be dominated by bolster species, whereas the eastern communities are more frequently dominated by shrubs or graminoids.Nomenclature follows Curtis (1963, 1967), Curtis & Morris (1975), Curtis & Stones (1978) and Willis (1970) except where authorities are given at first mention. Structural nomenclature follows Kirkpatrick (1983). 相似文献
3.
Caroline E. R. Lehmann Catherine L. Parr 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2016,371(1703)
Tropical grassy biomes (TGBs) are changing rapidly the world over through a coalescence of high rates of land-use change, global change and altered disturbance regimes that maintain the ecosystem structure and function of these biomes. Our theme issue brings together the latest research examining the characterization, complex ecology, drivers of change, and human use and ecosystem services of TGBs. Recent advances in ecology and evolution have facilitated a new perspective on these biomes. However, there continues to be controversies over their classification and state dynamics that demonstrate critical data and knowledge gaps in our quantitative understanding of these geographically dispersed regions. We highlight an urgent need to improve ecological understanding in order to effectively predict the sensitivity and resilience of TGBs under future scenarios of global change. With human reliance on TGBs increasing and their propensity for change, ecological and evolutionary understanding of these biomes is central to the dual goals of sustaining their ecological integrity and the diverse services these landscapes provide to millions of people.This article is part of the themed issue ‘Tropical grassy biomes: linking ecology, human use and conservation’. 相似文献
4.
Marcelino-José del Arco Aguilar Ricardo González-González Víctor Garzón-Machado Bernardo Pizarro-Hernández 《Biodiversity and Conservation》2010,19(11):3089-3140
The main vegetation units of the Canary Islands are briefly described and their current surface area established. The area of potential natural vegetation remnants is compared with the supposed original area, and expressed also as percent persistence, (area now/potential) × 100. We state that although the islands have between 40 and 50% of their surface under protection, several units of the most representative vegetation (e.g. like Euphorbia scrubs, thermo-sclerophyllous woodland and laurel forest) have retreated greatly, sometimes with little possibility of recovery. Willow, palm, tamarisk, and Plocama pendula communities, sandy beach vegetation, and small-area littoral ecosystems are also severely diminished in area. Comments are made about the conservation status of the most representative communities. 相似文献
5.
Bird community composition in an actively managed savanna reserve, importance of vegetation structure and vegetation composition 总被引:6,自引:1,他引:5
The mosaic of trees, shrubs and open grassland in mesic African savannas is highly dynamic and strongly influenced by mammal herbivory and fire. We investigated the bird fauna in four different savanna habitats to help assess the impacts of vegetation change on this component of faunal diversity. Birds were censused, plant species were identified and vegetation structure was measured in four different vegetation types (Acacia nilotica woodland, Acacia nigrescens woodland, broadleaf thicket and open grassland) in the Hluhluwe-Umfolozi Park in northern KwaZulu Natal, South Africa. Multivariate ordination analyses were used to determine the relative importance of vegetation structure and floristic composition in defining bird assemblages. The bird communities of the grasslands, the acacia woodlands, and the broadleaf woodlands were clearly separated on the first axis of the detrended canonical correspondence analysis (DCCA). Canopy cover and foliage height diversity (FHD) were strongly correlated with the first axis of DCCA, possibly reflecting a secondary successional series from grassland to woodland, known as bush encroachment. Floristic composition (based on presence–absence data only) seemed to be less important for bird community composition than vegetation structure. The results indicate that changes in vegetation structure, caused by bush encroachment, could cause concomitant changes in bird community composition. 相似文献
6.
Patterns of vegetation and grasshopper community composition 总被引:6,自引:0,他引:6
Summary A study was conducted to evaluate differences in rangeland grasshopper communities over environmental gradients in Gallatin Valley, Montana, USA. The concept of habitat type (Daubenmire 1966) was used as a basis for discriminating between groupings of patches based on vegetation. A total of 39 patches were selected that represented five recognized grassland habitat types (Mueggler and Stewart 1980), as well as two disturbed types (replanting within a known habitat type). Repeated sampling in 1988 of both the insect and plant communities yielded a total of 40 grasshopper (19 664 individuals) and 97 plant species. Detrended Correspondence Analysis (DCA) indicated that patch classifications based on presence and percent cover of plants were appropriate and showed good between-group (habitat type) separation for patches along gradients of precipitation/elevation and plant community complexity. Results from undisturbed habitats showed that plant and grasshopper species composition changed over observed environmental gradients and suggested that habitat type influenced not only species presence, but also relative abundance. Discussion is presented that relates results with patch-use and core and satellite species paradigms. 相似文献
7.
Georg Zizka Marco Schmidt Katharina Schulte Patricio Novoa Raquel Pinto Konstantin König 《Biodiversity and Conservation》2009,18(9):2449-2471
Chile is home to 23 species of Bromeliaceae, including 2 subspecies and 4 varieties. Twenty species are endemic to the country.
We examined 883 herbarium specimens from 27 herbaria for our treatment of the Bromeliaceae for the “Flora de Chile”. These
data and field observations resulted in a comprehensive database that we used to generate distribution maps for each species.
We applied ecological niche modelling to reveal distribution areas and centers of Bromeliaceae diversity. We further analysed
the collecting dates of the herbarium specimens to assess possible changes in species abundance. In this study we assess the
conservation status of the bromeliad species in Chile. IUCN categories were assigned to the 27 bromeliad taxa as follows:
Critically endangered: 4, Endangered: 6, Vulnerable: 11, Near threatened: 2, Least concern: 4. No species has become “Extinct”
up to now. We also put forth a hypothesis about their biogeographic history. 相似文献
8.
Trophic status of Tilitso,a high altitude Himalayan lake 总被引:1,自引:1,他引:0
Morihiro Aizaki Akira Terashima Hiroyuki Nakahara Takayuki Nishio Yuzaburo Ishida 《Hydrobiologia》1987,153(3):217-224
The trophic status and water quality of Lake Tilitso (4920 m above sea level) in a high altitude region in central Nepal were
surveyed in September, 1984. The lake is rather large with a maximum depth of 95 m and a surface area of 10.2 km2. The lake water was turbid due to glacier silt and the euphotic layer was only 5 m deep. The nutrient concentration was very
low with total phosphorus concentration 1–6 μg l−1, and DTN concentration 0.10–0.22 mg l−1. The phytoplankton biomass and chlorophyll-a concentration were also low. Primary production was estimated to be about 12
mg C m−2 d−1. The concentrations of particulate matter and most cations and bacterial number were higher in the epilimnion than in the
hypolimnion. The trophic status of this lake was estimated as ultraoligotrophic. 相似文献
9.
Ida Theilade Lars Schmidt Phourin Chhang J. Andrew McDonald 《Nordic Journal of Botany》2011,29(1):71-80
As part of recent field studies, a hitherto undescribed type of evergreen freshwater swamp forest was discovered in Stung Treng Province, Cambodia. The swamp forest occurs in at least six disjunct localities and is dominated by hydrophytic trees (Eugenia spp., Ficus spp., Litsea spp., Macaranga triloba, Myristica iners and Pternandra caerulescens). Although these same genera also occur in upland forests, most are represented by different species in the swamps. Livistona saribus emerges from the canopy as an indicator species of this vegetation type while dense stands of other palms (Calamus, Areca, Licuala) and sporadic, dense populations of tree ferns (Cibotium barometz) dominate the understory. Pneumatophores, stilt roots, and aerial roots characterize the hydrophytes. The floristic composition indicates that the forest type is distinct compared to other swamp forests described from the region and worthy of protection based on its rarity and ecological uniqueness. 相似文献
10.
Historical evidences suggest that the Himalayas have some strong biogeographical links to the Alps. In view of this fact,
the present study aims to understand the similarities in plant species distribution and their ethnobotanical uses in the Indian
Himalayas and the Slovenian Alps. The plant species common in both the mountain systems and used by local inhabitants were
compiled by extensive literature search and also by carrying out primary surveys. Ethnobotanical information was collected
through personal interviews of villagers with the help of local assistants and also through direct and indirect observations
made during the field surveys. A total of 59 ethnobotanical species representing 17 families common in both the Indian Himalayas
and the Slovenian Alps were documented, of these 78% obtained medicinal properties and traditionally used by local people
for curing diseases. Comparatively, people of the Indian Himalayas used plants for medicine in higher percentage (73%) than
the people of Slovenia (42%). Of the total medicinal plants, only 7 plant species such as Acorus
calamus, Capsella
bursa-partoris, Hypericum
perforatum, Origanum
vulgare, Prunella
vulgaris, Solanum
nigrum and Urtica
dioica had some common uses in both the Slovenian Alps and the Indian Himalayas. In the Slovenian Alps, the maximum ethnobotanical
species (61%) had wide distribution range whereas maximum ethnobotanical species in the Indian Himalayas (62%) had localized
distribution. Though, 27% of common ethnobotanical species belonged to different threat categories, only 2 species—Taxus
baccata and Hippophae
rhamnoides—are placed under similar threat category in these two different mountain areas. The study unfolds relationship in plant species
distribution and their ethnobotanical uses along with offering an opportunity to provide information on uses of plant species
though available but unknown to community. 相似文献
11.
12.
Michael Mogie 《Biological journal of the Linnean Society. Linnean Society of London》1986,28(3):321-329
Biologists have conclusively failed to arrive at a generally acceptable definition of sexual reproduction. Because of this, several reproductive processes are seen as sexual by some authors but as asexual by others. Included among these are automictic methods of reproduction. Automixis describes several reproductive processes whereby a new individual derives from a product or products of a single meiotically dividing cell. Several forms involve an episode of nuclear fusion and it is argued that, because of this, they should be seen as sexual processes irrespective of whether the fusing bodies are differentiated as gametes or are simply meiotic tetrad nuclei. Other forms involve no episode of nuclear fusion and it is argued that, because of this, they should be seen as asexual processes. These latter forms involve the generation of diploid eggs either by restitutional meioses, or by an endomitotic event preceding or following a reductional meiosis, or involve the generation of a diploid embryo by the fusion of cleavage division nuclei in a haploid embryo; in each case the egg develops parthenogenetically. In addition to the disagreement that exists over the reproductive status of automixis, considerable confusion exists over its taxonomic distribution. It is often described as being restricted to a few species of insects, where it is parthenogenetic, but in factde range of taxa, including both isogamous and anisogamous plants and fungi, where it may be either parthenogenetic or non-parthenogenetic. This confusion results both from a failure of many biologists writing on this subject to adequately consider the variation in life-cycles existing between major taxa and from a general failure by botanists and mycologists to distinguish between automixis and autogamous forms of self-fertilization (in which the fusing nuclei derive from different meioses). It is further compounded by a proliferation of synonyms for automictic processes. Thus in a number of publications automictic processes are variously described as being matromorphic, thelytokous, parthenogamic, autogamic or apomictic rather than as being automictic. 相似文献
13.
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 (Xla in 103 km2) of the nations in the region were, Yin = 218.961 Ln(Xla) – 843.1 (R2 = 0.735; P < 0.001) and Ye = 28.445 Ln Xla?134.47 (R2 = 0.534; P < 0.01), respectively, and between indigenous and endemic species richness was Ye = 0.079Xn? 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. 相似文献
14.
As ancient gymnosperm and woody plants, cycads have survived through dramatic tectonic activities, climate fluctuation, and environmental variations making them of great significance in studying the origin and evolution of flora biodiversity. However, they are among the most threatened plant groups in the world. The principal aim of this review is to outline the distribution, diversity, and conservation status of Cycas in China and provide suggestions for conservation practices. In this review, we describe the taxonomy, distribution, and conservation status of Cycas in China. By comparing Chinese Cycas species with its relatives worldwide, we then discuss the current genetic diversity, genetic differentiation of Cycas, and try to disentangle the potential effects of Quaternary climate changes and topographical events on Cycas. We review conservation practices from both researchers and practitioners for these rare and endangered species. High genetic diversity at the species level and strong genetic differentiation within Cycas have been observed. Most Cycas species in southwest China have experienced population retreats in contrast to the coastal Cycas's expansion during the Quaternary glaciation. Additionally, human activities and habitat fragmentation have pushed these endangered taxa to the brink of extinction. Although numerous efforts have been made to mitigate threats to Cycas survival, implementation and compliance monitoring in protection zones are currently inadequate. We outline six proposals to strengthen conservation measures for Cycas in China and anticipate that these measures will provide guidelines for further research on population genetics as well as conservation biology of not only cycads but also other endangered species worldwide. 相似文献
15.
S. M. Haslam 《Hydrobiologia》1996,340(1-3):345-348
The welcome increase in projects increasing river vegetation prompts theoretical consideration. To restore is to bring back what was there before — but at what period? 1860 to 1940 is suggested, as ‘traditional’. Traditional rivers differ greatly between river types and between rivers: in water, structural and biotic characters, and Sense of Place. Aiming at these, holistically, is aiming at restoration. Aiming at part, or trying to convert rivers to a Standard Recommended river is, at best, enhancement. The latter development lessens the unique variety and special features of rivers that are the heritage of each country. 相似文献
16.
Gregor Kozlowski Sandra Bürcher Matthieu Fleury Fanny Huber 《Biodiversity and Conservation》2009,18(3):649-662
The purpose of this study was to examine the composition, distribution, ecology, and conservation status of the Atlantic elements
of the Swiss flora. About 195 Atlantic and 80 Mediterranean–Atlantic vascular plant species of the European flora have been
used as the basis for our analysis. The complete list of 3,143 taxa has been used as the reference for the Swiss flora. The
distributions of the species are illustrated in coincidence maps based on the computer database of the Data Centre of the
Swiss Flora in Geneva, Switzerland. Our study demonstrates clearly that the Atlantic flora of Europe requires a new biogeographical
appraisal. The Swiss flora comprises 66 Atlantic and Mediterranean–Atlantic taxa, which are taxonomically and ecologically
highly diverse. Switzerland contains 44% of all European Sub-Atlantic plants. This confirms the Sub-Atlantic geographical
position of Switzerland. Only one Eu-Atlantic species growing in Switzerland, Vicia orobus, can be classified as native with certainty. This species is critically endangered and merits the highest conservation priority.
Although a very alpine country, Switzerland has a relatively large number of Mediterranean–Atlantic species. The Atlantic
and Mediterranean–Atlantic plants are a very threatened group in Switzerland, with wetland plants the most imperilled ecological
group.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
17.
Weight loss and changes in body composition at high altitude 总被引:9,自引:0,他引:9
18.
19.
《Journal of bryology》2013,35(1):12-19
AbstractScotland’s mountains are home to a rare and unique liverwort community, ‘the oceanic-montane liverwort-rich heath’, but its component species are absent from regions where they could potentially thrive. Many biological characteristics of these species are unknown, making it impossible to explain the reasons for their rarity; however, they have not been observed to produce sporophytes within Britain. We use ex situ cultivation of whole liverworts and fragments, and in situ cultivation of fragments, to assess the growth rate and the potential for vegetative reproduction of several species. Most of the species grew from both fragments and as whole plants, indicating that the rarity of the liverwort heath is not due to poor powers of regeneration. We propose that growth rate and the potential to regenerate from fragments are important factors structuring the liverwort heath community, at least locally. Furthermore, this study demonstrates that there is potential for ex situ conservation of rare liverwort species, in situ enhancement of existing populations, and creation of new ones. 相似文献
20.
Josiah Mandiporeva Taashwa Pioneer Gamundani Brian Gurajena Kudzai Mpakairi Terrance Magqina 《African Journal of Ecology》2023,61(1):185-203
This study investigated spatial distribution and effects of Lantana camara invasion on soil properties and vegetation composition in Tugwi-Mukosi Recreational Park. Supervised classification with the Random Forest classifier was used to map L. camara in the park. The study area was stratified into two categories based on soil type and the extent of L. camara invasion. Stratified random sampling was used in data collection to assess differences in species diversity and soil properties in the park. Results revealed that L. camara covered an area of 1772 ha. Using Random Forest classification, the study obtained an accuracy score of 92.1% and an F1 score of 86.25%. Two-way ANOVA showed significant effect of L. camara invasion on soil moisture (F = 28.143, p = 0.000), organic matter (F = 13.377, p = 0.003), pH (F = 1272.369, p = 0.000), total nitrogen (F = 51.762, p = 0.000), total phosphorus (F = 5.000, p = 0.045), woody species density (F = 4.987, p = 0.027), basal area (F = 10.393, p = 0.001), grass species richness (F = 196.258, p = 0.000) and grass cover (F = 3.637, p = 0.042). These results suggest that L. camara was modifying the soil and vegetation properties of the ecosystem which has implications on biodiversity. 相似文献