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1.
Anzar Ahmad Khuroo Irfan Rashid Zafar Reshi G. H. Dar B. A. Wafai 《Biological invasions》2007,9(3):269-292
Compilation of alien flora from phytogeographically distinct regions is of immediate relevance not only for better understanding
the patterns of plant invasion but also for explicating the processes promoting invasion at local, regional or global scales.
Despite being at higher risk of invasion by plants because of its European colonial past, south Asia has received very little
attention in respect of characterization of its alien flora. This paucity of baseline data necessitated compilation of the
first catalogue of alien flora from the Kashmir Himalaya—a phytogeographically distinct south Asian region nestled in the
northwestern folds of Himalayan biodiversity hotspot. Total alien flora of the region is represented by 571 plant species,
belonging to 352 genera and 104 families. It constitutes a relatively higher (29%) proportion of the total flora of the region.
Families with largest number of alien representatives are Poaceae (60 species), Asteraceae (54 species), and Brassicaceae
(30 species). However, families such as Amaranthaceae (83%) and Chenopodiacae (71%) show higher percentage of aliens relative
to their total number of plant species in the region. Most of the alien plant species (38%) trace their origin to Europe,
followed by Asia (27%) and Africa (15%). Present study also reports, for the first time, occurrence of seven plant species
in this region. Each alien plant species is provided with information on the origin, habit, mode/purpose of introduction,
current invasion status, altitudinal range and the primary published source. 相似文献
2.
Insha Muzafar Gousia Mehraj Maroof Hamid Irfan Rashid Akhtar H. Malik 《Plant biosystems》2019,153(2):222-230
In the urban landscapes, scientific understanding of the roadside vegetation is a prerequisite for better planning and designing of sustainable cities. The Srinagar city, located in the Indian Himalayas, represents an urban biodiversity hotspot but the information about the floristic diversity especially along its roadsides is lacking. In order to fill this knowledge gap, the present study using field-based plant collection surveys was undertaken to investigate the floristic diversity growing along the roadsides of Srinagar. A total of 206 vascular plant species were recorded with the proportion of alien species relatively higher (52%) than the native species (48%). Of the 108 alien species, 24 were invasive, 44 naturalized, 12 casual and 23 were cultivated. Most of the species were herbs (165 spp.) and the majority of these were wild growing (155 spp.). Based on Raunkiaer’s lifeform characterization, therophytes (94 spp.) were the most dominant. Interestingly, the therophytes harboured the highest number of alien species (50 spp.), followed by phanerophytes (29 spp.). There was significant difference between the floristic spectrum obtained during the present study and the normal Raunkiaer’s spectrum. The present study provides policy-relevant baseline data which can guide the urban planners to develop sustainable planning in this Himalayan city. 相似文献
3.
CHRISTOPHER J. WALSH† KYLIE A. WALLER JANELLE GEHLING RALPH MAC NALLY 《Freshwater Biology》2007,52(3):574-587
1. Restoration of riparian forests has been promoted as a means of mitigating urban impacts on stream ecosystems. However, conventional urban stormwater drainage may diminish the beneficial effect of riparian forests.
2. The relative effects of riparian deforestation and catchment urbanisation on stream ecosystems have rarely been discriminated because urban land use and riparian degradation usually covary. However, land use at three scales (channel canopy cover along a 100-m site, riparian forest cover within 200 m of the channel for 1 km upstream, and catchment imperviousness) covaried only weakly along the lowland Yarra River, Victoria, Australia.
3. We tested the extent to which each land use measure explained macroinvertebrate assemblage composition on woody debris and in the sediments of pools or runs in the mainstem Yarra River in autumn and spring 1998.
4. Assemblage composition in both habitats and in both seasons was most strongly correlated with proportion of catchment covered by impervious surfaces. Sites with higher imperviousness had fewer sensitive taxa (those having a strong positive influence on indicators of biological integrity) and more taxa typical of degraded urban streams. Sensitive taxa rarely occurred in sites with >4% total imperviousness. However, within sites of similar imperviousness, those with more riparian forest cover had more dipteran taxa. Channel canopy cover did not explain assemblage composition strongly.
5. Riparian forest cover may influence richness of some macroinvertebrate taxa, but catchment urbanisation probably has a stronger effect on sensitive taxa. In catchments with even a small amount of conventionally drained urban land, riparian revegetation is unlikely to have an effect on indicators of stream biological integrity. Reducing the impacts of catchment urbanisation through dispersed, low-impact drainage schemes is likely to be more effective. 相似文献
2. The relative effects of riparian deforestation and catchment urbanisation on stream ecosystems have rarely been discriminated because urban land use and riparian degradation usually covary. However, land use at three scales (channel canopy cover along a 100-m site, riparian forest cover within 200 m of the channel for 1 km upstream, and catchment imperviousness) covaried only weakly along the lowland Yarra River, Victoria, Australia.
3. We tested the extent to which each land use measure explained macroinvertebrate assemblage composition on woody debris and in the sediments of pools or runs in the mainstem Yarra River in autumn and spring 1998.
4. Assemblage composition in both habitats and in both seasons was most strongly correlated with proportion of catchment covered by impervious surfaces. Sites with higher imperviousness had fewer sensitive taxa (those having a strong positive influence on indicators of biological integrity) and more taxa typical of degraded urban streams. Sensitive taxa rarely occurred in sites with >4% total imperviousness. However, within sites of similar imperviousness, those with more riparian forest cover had more dipteran taxa. Channel canopy cover did not explain assemblage composition strongly.
5. Riparian forest cover may influence richness of some macroinvertebrate taxa, but catchment urbanisation probably has a stronger effect on sensitive taxa. In catchments with even a small amount of conventionally drained urban land, riparian revegetation is unlikely to have an effect on indicators of stream biological integrity. Reducing the impacts of catchment urbanisation through dispersed, low-impact drainage schemes is likely to be more effective. 相似文献
4.
Zishan Ahmad Wani;Shreekar Pant; 《Nordic Journal of Botany》2023,2023(7):e03982
The present study attempts to comprehensively study the floristic elements of Gulmarg Wildlife Sanctuary (GWLS), Kashmir Himalaya. During the present study 364 species of vascular plants belonging to 227 genera and 74 families were recorded from the sanctuary. A total of 18 communities (10 within forest and 8 within alpine zone) were identified. Forest zone of the sanctuary was represented by shady moist, dry, bouldery, rocky, riverine and exposed habitats; whereas the alpine zone was represented by bouldery, riverine and moist and exposed habitats. Of the total 364 reported plant species, 161 species were native to Himalayan region and the remaining i.e. 203 species were non-natives. Out the total 161 native plant species, 82 were endemic to the Himalayan region. Further, 22 plant species were having threatened status in Jammu and Kashmir. Major threats to biodiversity within the sanctuary include overexploitation, habitat degradation, overgrazing, invasive species, human settlements, huge tourism influx and pollution. In the present study, based on the 'conservation priority index' (CPI) of the plant species, 51 plant species were assessed to be threatened in GWLS. Further, maximum CPI of dry and shady moist habitats and Aesculus indica–Pinus wallichiana mixed and Taxus wallichiana–Prunus cornuta–Aesculus indica mixed communities reveals that proper management of these prioritized habitats and communities would help in maintaining the natural ecosystems and conservation of species of the sanctuary. Present study recommends that awareness about the values of biodiversity for sustenance through organization of training workshops, awareness camps need to be created among the local inhabitants as well as visitors. Further, no in-depth explorations for community characterization of forest and as well as alpine ecosystems of Kashmir Himalaya have been conducted; present study in the GWLS provides a template, which can be replicated in other protected as well as unprotected areas of the Kashmir Himalaya. 相似文献
5.
Forests of an elevational transect in the central Himalayan region were studied regarding their tree species composition and structural features. In spite of many differences in compositional and structural features in different forest stands, the arrangement of stands in the ordinations based separately on species composition and structural features exhibit many similarities. Disturbances such as landslides and forest fires play the most important role in the distributor of particular species. 相似文献
6.
7.
Riparian forest plantings are a well‐established restoration technique commonly used to stabilize banks and intercept nutrient flow from adjacent agricultural fields. Tree species planted for these efforts may not reflect mature forest communities within the same region. Given contemporary research on links between biodiversity and ecosystem functioning, we conducted a leaf‐litter decomposition study to investigate how mixing of detrital resources that reflect forest community composition would regulate in‐stream leaf litter. Leaf litter bags containing material from a mature forest (Liriodendron tulipifera, Acer rubrum, Quercus rubra, full factorial treatments = 7) and a restored riparian forest (Cornus sericea, Fraxinus pennsylvanica, Platanus occidentalis, full factorial treatments = 7) were deployed in a stream reach that experienced riparian reforestation in 2004. Litter from the restored riparian community had less mass remaining (45.28 ± 2.27%) than that from the mature riparian community (54.95 ± 2.19%) after 5 weeks. In addition, mixed litter treatments in the restored riparian community had less mass remaining (40.54 ± 2.37%) than single‐species treatments (51.80 ± 4.05%), a pattern not observed in the mature forest community. Results highlight the importance of planting mixed‐species assemblages as this structure may regulate processes such as decomposition and food‐web structure, processes often not targeted in the restoration plans. 相似文献
8.
Synopsis I studied effects of deforestation on diet and condition of three characid species; Astyanax zonatus, Knodus gamma, and Prionobrama filigera in small streams in the Ecuadorian Amazon. The best condition of K. gamma was found at sites with low canopy cover, while the best condition of P. filigera was found at sites with high canopy cover. Deforestation changed population structure of A. zonatus by decreasing mean size of individuals, but this was not associated with lower fish condition. A. zonatus was omnivorous, and fed equally on invertebrate and plant food. A. zonatus increased feeding on aquatic food items (filamentous algae and fish scales) in the deforested sites (43%) compared to the forested sites (16%). K. gamma was an omnivorous species with preference for invertebrates. K. gamma was mainly feeding on terrestrial food sources in the forested sites, but switched to equal feeding between terrestrial and aquatic food sources in the deforested sites. P. filigera was an terrestrial insectivore feeder, and no differences in the overall food categories was found between stream groups. In contrast, there were no pronounced difference in the composition of invertebrate taxa in the stomachs of K. gamma between stream groups. However, less empty stomachs were observed among K. gamma in the deforested sites. The stomach contents of P. filigera showed great changes in composition of the predominating prey taxa between stream groups and less empty stomachs were observed among P. filigera in the forested sites. Food availability and utilisation seemed to be of main importance for the condition of these fish. Deforestation seems to favour species with high availability to utilise aquatic food items. In contrast, deforestation seems to have negative effects on species that are specialised on terrestrial invertebrates, and have low capacity to switch between aquatic and terrestrial food items. 相似文献
9.
10.
Aims In view of the growing interest in modelling the potential spread of invasive species, prediction of plant invasiveness on the basis of native range size holds considerable promise. Our objective was to use a simple model to evaluate whether a wider native range predisposes plant species to become invasive in non-native regions and to easily identify potential invaders on this basis. The Kashmir Himalayan alien flora, of which a large proportion is native to Europe, was used to test this model.Methods The Kashmir Himalayan alien flora comprises 436 species of vascular plants at different stages of invasion. We focussed on plant species at two critical invasion stages (sensu Colautti and MacIsaac 2004), i.e. Stage II (species that are just at the earliest phase of introduction) and Stage V (species that are widespread and dominant in the invaded region and are thus considered invasive). We used the territorial distribution in Europe (number of countries) as a surrogate for the native range size of plants of European origin.Important findings Using a subset of 88 species, for which information on the native European range was available, we showed that a large proportion (68%) of Stage II species growing in the Kashmir Valley had a relatively restricted European range (present in ≤20 countries); on the other hand, 77% of Stage V species had an extensive native range (present in>20 countries). We consequently hypothesized that 14 Kashmir Himalayan Stage II species of European origin that are distributed in>20 European countries are at risk of becoming future invaders in Kashmir. On the other hand, those Kashmir Himalayan Stage II species of European origin distributed in ≤20 European countries are less likely to become invasive. Although this analysis is quite simple, the data suggest that a wider native range is a good predictor of plant invasiveness and could be used as a simple and low-cost early warning tool in predicting potential invasive species. 相似文献
11.
S. KIKUCHI W. SUZUKI N. BAN A. KANAZASHI H. YOSHIMARU 《Molecular ecology resources》2005,5(4):869-870
Salix hukaoana is an endangered riparian tree that is found and known only in several isolated sites in eastern Japan, and that has been suffering from the loss and fragmentation of its habitat. To investigate the genetic variation and structures of this willow in these sites, eight polymorphic microsatellites with three to eight alleles were characterized. Cross‐species amplification was successful for many of the loci using the congeners Salix sachalinensis and Chosenia arbutifolia. This set of microsatellites will be useful for the study of the spatial genetic structures of S. hukaoana and other coexisting willows suffering from habitat fragmentation in riparian forests. 相似文献
12.
帽儿山地区不同类型河岸带土壤的反硝化效率 总被引:5,自引:1,他引:5
以帽儿山地区森林背景下的森林、皆伐、草地河岸带和农田背景下的森林、裸地河岸带土壤为研究对象,采用硝态氮消失法,研究了不同背景下各类型河岸带的反硝化强度及其影响因素.结果表明:各类型河岸带中,农田背景下的森林河岸带土壤反硝化强度最大,其硝态氮消失率的变化范围为46.79%~91.13%,农田背景下的裸地河岸带土壤反硝化强度最小,其硝态氮消失率的变化范围为15.64%~81.84%;森林背景下土壤反硝化强度的大小顺序为皆伐河岸带〉森林河岸带〉草地河岸带,其硝态氮消失率的变化范围依次为42.06%~90.39%、28.24%~85.73%、21.44%~83.11%.研究区河岸带表层土壤的反硝化强度大于底层.河岸带土壤反硝化强度均受可利用碳、硝态氮的限制,各类型河岸带以农田背景下森林河岸带土壤反硝化潜力最大. 相似文献
13.
Given the extent of tropical forest deforestation and as a number of conservation programmes and local communities rely on forest fragments, it has become important to understand how fragment exploitation by local communities affects forest structure and function. The effects of forest exploitation on forest structure and status of forest fragments were investigated in 20 nonreserved forest fragments in central Uganda. Enumeration of plots showed that tree species composition of the forest fragments was 60.0%, 23.7% and 6.3% for under‐storey, middle and top canopy trees respectively. The major activity was fuel wood extraction (65%), followed by brick making (10%), cultivation and livestock paddocks (10%), charcoal burning (5%), local brew distillation and others (5%). These extractive processes caused drastic structural changes, habitat degradation and destruction. Tree stumps enumeration indicated that under storey trees formed the highest proportion for wood extraction. There was no significant difference in the level of forest exploitation (basal area loss) among forest patches of varying sizes. 相似文献
14.
西双版纳傣族村寨对湿地植物的传统利用 总被引:1,自引:0,他引:1
作者用半结构访谈与关键人物访谈相结合,并佐以证据标本采集的民族植物学研究方法,对云南省西双版纳3个自然环境和经济社会条件差异较大的典型傣族村寨(曼降,曼安,曼伞)居民的湿地植物知识,以及不同性别、年龄人群掌握湿地植物知识的差异作了统计分析。研究结果表明:(1)西双版纳傣族村寨利用的湿地植物种类丰富,经鉴定的有46科102种,以湿生植物为主;利用类型有食用类、药用、代茶类和宗教类等,以食用类为主。(2)三个村寨中以曼伞调查和采集到的植物种类最多,曼安次之,曼降最低。3个村寨利用的湿地植物种类的相似性低。这与村寨周围的自然植被类型及其干扰程度密切相关。(3)统计分析显示,村寨的自然环境与经济发展状况对该村村民传统湿地知识的掌握有重要的影响。食用和药用、代茶植物知识在3个村寨都表现为年长组(>45岁)明显高于年轻组(≤45岁,P<0.05),而男性和女性对不同知识的掌握则因村寨自然环境和经济发展状况的不同而各不相同。植物多样性和民族传统文化多样性的关系显示出传统知识的传承对植物多样性保护是十分重要的。 相似文献
15.
Properties of the top 30 cm of soil under plantations of 1-yr to 8-yr old Eucalyptus (the hybrid E. tereticornis) and in adjacent natural mixed broad-leaved forest were compared in the sub-tropical zone of the central Himalaya. Various soil-physical characteristics decreased with increasing age; soil-chemical properties, notably organic carbon, total N, P and K decreased as a result of reforestation with Eucalyptus and further decreased with increasing age of the plantation. 相似文献
16.
Robin Adair Jean-Louis Sagliocco Eligio Bruzzese 《Australian Journal of Entomology》2006,45(4):259-267
Abstract Willows ( Salix spp.) are Weeds of National Significance in Australia where a large number of taxa are naturalised in temperate regions and can cause serious environmental degradation of riparian and wetland habitats. Several species are of economic or ornamental value and conflicts of interest could arise with planning their suppression. Biological control of six willow species ( S. alba L., S. cinerea L . , S. fragilis L., S. nigra Marshall, S. viminalis L., S . x rubens Schrank) is under consideration in Australia using three approaches based on targeting different morphological structures. A rich phytophagous biota associated with Salix in their regions of origin indicate a range of organisms are available for development as biological control agents. Implementation strategies will depend on the host species targeted for biological control, their reproductive strategies, the level of control required to reduce environmental impacts and the level of conflict of interest associated with a biological control program. 相似文献
17.
David Hooper 《Freshwater Biology》2013,58(11):2310-2324
- Stream conservation and restoration strategies commonly focus on preserving extant riparian forest and restoring riparian habitat. Though these practices are beneficial to stream habitat, they may not suffice to restore stream condition in catchments heavily influenced by intensive land use.
- To evaluate this hypothesis, we measured invertebrate populations in 12 streams affected by different land‐use types (cultivated, developed, forested and grassland). Within each stream, we compared reaches with and without riparian buffers of remnant mature forest. Within each reach, we calculated the relative abundance of individuals from the insect orders Ephemeroptera, Plecoptera and Trichoptera (%EPT) and assessed specific conductance, dissolved oxygen (DO), temperature and substratum composition.
- Forested catchments had the highest %EPT (average 23.8) followed by grassland (16.1), cultivated (1.96) and developed (0.31). Reaches with forested buffers present were not associated with higher %EPT in forested, cultivated or developed catchments. In grassland catchments, however, %EPT was about eightfold higher in reaches with forested buffers than those without.
- High values of %EPT were associated with large stream substratum and low specific conductance and temperature, which were most common in forested catchments. Developed and cultivated catchments did not follow this pattern, %EPT being uniformly low, even where abiotic conditions were similar to forested catchments.
- These results confirm that intensive urban and cultivated land uses at the catchment scale degrade stream biological communities. They also indicate that patchy forested riparian corridors, as found in many restoration projects, are probably insufficient to mitigate severe, large‐scale biological degradation.
18.
稳定性是植物群落结构与功能的综合特征。该文运用模糊综合评判理论评价了山西文峪河上游13种河岸林群落的稳定性。基于群落整体稳定性和结构稳定性的考虑, 选取乔木层优势树种更新潜力、物种多样性、Godron指数、立地质量和保护程度等5项特征指标, 通过计算各群落5项指标隶属度的平均值来评价群落稳定性。研究结果表明, 多数群落的稳定性隶属度介于0.40-0.60, 属于低山森林演替系列的青杨辽东栎(Populus cathayana + Quercus wutaishanica)混交林和油松白桦(Pinus tabulaeformis + Betula platyphylla)混交林的稳定性居中; 中高山森林演替系列中, 群落稳定性随着演替的进展而增加, 青杨(Populus cathayana)林结构简单, 稳定性最低, 青杄(Picea wilsonii)林接近演替顶极, 稳定性最高; 但并非只有近演替顶极的群落是稳定的, 客观存在的各种林冠干扰和河岸生境的高度异质性也使得白杄杨桦(Picea meyeri + Populus cathayana + Betula platyphylla)混交林、落叶松白杄(Larix principis-rupprechtii + Picea meyeri)混交林和落叶松青杄(Larix principis- rupprechtii + Picea wilsonii)混交林有较高的稳定性。 相似文献
19.
对塔里木河中游荒漠河岸林林隙基本特征和干扰状况进行了研究。结果表明:形成的林隙形状近似于椭圆形,椭圆长短轴比率在扩展林隙(EG)和冠空隙(CG)有所不同,平均分别为1.52和2.31;林隙密度约为62.5个?hm-2, EG和CG在塔里木荒漠河岸林景观中的面积比例分别为69.52%和29.03%,干扰频率分别为1.45%?a-1和0.61%?a-1,林隙干扰返回间隔期约为164a。林隙大小结构表现出以小林隙为主的偏正态分布,EG大小40—200m2,CG大小0—80m2。林隙形成速率为1.30个?hm-2a-1,20—30a前形成的林隙最多。林隙形成方式由树木折干 枯立形成的最为普遍,占形成木总数95.73%。林隙大多由2—5株形成木形成, 而由4株形成木创造的林隙最多,平均每个林隙拥有形成木4.1株。林隙形成木主要为森林建群种,林隙形成木分布最多的径级在5—25cm,高度在4—8m,每株形成木所能形成的EG面积为27.12m2, CG面积为11.32m2。边缘木的径级结构呈正态分布,而高度结构呈偏左的正态分布,平均每个林隙拥有8.375株边缘木,林隙边缘木平均胸径比形成木平均胸径高73.1%,表明荒漠河岸林林隙干扰十分频繁,地下水位的持续下降是林隙形成的驱动力。 相似文献
20.
Julieta Benítez‐Malvido 《Biotropica》2012,44(1):53-62
The interaction of plants with insect herbivores and fungal pathogens can affect community dynamics, but there is little information on how this antagonistic interaction may be altered in human‐disturbed tropical systems. We examined whether the amount and quality of foliar damage on the pioneer herbs Heliconia latispatha and Heliconia collinsiana are distinct on road edges and secondary riparian vegetation compared with natural gaps in continuous forest (controls) in Mexico. We also investigated some physical and biological mechanisms that may jointly explain such differences. The overall insect damage in H. latispatha was similar between road edges and natural forest gaps (8.0% vs. 7.2% of leaf area). Damage by caterpillars, however, decreased from 4.2 percent in forest gaps to 0.5 percent on road edges, whereas damage by leaf‐cutting ants increased from 0 to 5.8 percent. In secondary riparian vegetation, where none of the leaves sampled were attacked by ants, overall herbivore damage in H. collinsiana was less than half that observed in forest gaps (3.0% vs. 6.7%), and driven mainly by differences in caterpillar damage (2.5% vs. 6.2%). By contrast, attack by leaf fungal pathogens was two to three times greater in both human‐disturbed habitats than in gaps (8.2–9.6% vs. 3.7–4.2%). Potential mechanisms underlying these differences involved human‐induced shifts in air and soil temperature driven by greater light availability, as well as changes in relative humidity, leaf toughness, foliar condensed tannins, and local abundance of herbivores. Our results indicate that human disturbance alters insect herbivory and may increase proliferation of leaf disease. Abstract in Spanish is available in the online version of this article. 相似文献