Important Habitat (important + habitat)

Distribution by Scientific Domains


Selected Abstracts


Habitat models of bird species' distribution: an aid to the management of coastal grazing marshes

JOURNAL OF APPLIED ECOLOGY, Issue 5 2000
T. P. Milsom
1.,Coastal grazing marshes comprise an important habitat for wetland biota but are threatened by agricultural intensification and conversion to arable farmland. In Britain, the Environmentally Sensitive Area (ESA) scheme addresses these problems by providing financial incentives to farmers to retain their grazing marshes, and to follow conservation management prescriptions. 2.,A modelling approach was used to aid the development of management prescriptions for ground-nesting birds in the North Kent Marshes ESA. This ESA contains the largest area of coastal grazing marsh remaining in England and Wales (c. 6500 ha) and supports nationally important breeding populations of lapwing Vanellus vanellus and redshank Tringa totanus. 3.,Counts of ground-nesting birds, and assessments of sward structure, surface topography and wetness, landscape structure and sources of human disturbance were made in 1995 and again in 1996, on 19 land-holdings with a combined area of c. 3000 ha. The land-holdings varied from nature reserves at one extreme to an intensive dairy farm at the other. 4.,Models of relationship between the presence or absence of ground-nesting birds and the grazing marsh habitat in each of c. 430 marshes were constructed using a generalized linear mixed modelling (GLMM) method. This is an extension to the conventional logistic regression approach, in which a random term is used to model differences in the proportion of marshes occupied on different land-holdings. 5.,The combined species models predicted that the probability of marshes being occupied by at least one ground-nesting species increased concomitantly with the complexity of the grass sward and surface topography but decreased in the presence of hedgerows, roads and power lines. 6.,Models were also prepared for each of the 10 most widespread species, including lapwing and redshank. Their composition differed between species. Variables describing the sward were included in models for five species: heterogeneity of sward height tended to be more important than mean sward height. Surface topography and wetness were important for waders and wildfowl but not for other species. Effects of boundaries, proximity to roads and power lines were included in some models and were negative in all cases. 7.,Binomial GLMMs are useful for investigating habitat factors that affect the distribution of birds at two nested spatial scales, in this case fields (marshes) grouped within farms. Models of the type presented in this paper provide a framework for targeting of conservation management prescriptions for ground-nesting birds at the field scale on the North Kent Marshes ESA and on lowland wet grassland elsewhere in Europe. [source]


Wetlands, livelihoods and sustainability in Tanzania

AFRICAN JOURNAL OF ECOLOGY, Issue 2009
A. G. Mwakaje
Abstract Wetlands in Tanzania are among the world's most biologically productive ecosystems and are rich in species diversity. Wetlands support family livelihoods through crop production, grazing pastures and direct resource extractions. Ecologically, wetlands are instrumental in water storage, filtration, flood control and toxic retention and are also important habitat for biodiversity both flora and fauna. The last 30 years have witnessed rapid degradation of wetlands which threatens livelihoods; disturbs ecological settings and leads into unsustainable development. In this study, an attempt has been made to describe the livelihoods and sustainability issues of the Bahi Wetlands in Central Tanzania. This is a semi-arid area and therefore the wetland plays a key role socio-economically and environmentally. Data were collected from 200 households in Ngaiti and Kitalalo villages using structured and semi-structured questionnaires. There were also focused groups interviews, key informants and Participatory Rural Appraisal methods. Findings show Bahi Wetlands to play a significant role in livelihoods, cultural and ecological functions. However, the sustainability of the wetlands is threatened by over-cultivation, overgrazing and over-extraction of natural resources directly. Livelihood diversifications through credit provision, improved extension services and strengthened local institutions, are recommended. Wetlands policy and laws should be developed and enforced. [source]


Land use history and site location are more important for grassland species richness than local soil properties

NORDIC JOURNAL OF BOTANY, Issue 6 2009
Sara A. O. Cousins
Lately there has been a shift in Sweden from grazing species-rich semi-natural grasslands towards grazing ex-arable fields in the modern agricultural landscape. Grazing ex-arable fields contain a fraction of the plant species richness confined to semi-natural grasslands. Still, they have been suggested as potential target sites for re-creation of semi-natural grasslands. We asked to what extent does fine-scale variation in soil conditions, management history and site location effect local plant diversity in grazed ex-arable fields. We examined local soil conditions such as texture, pH, organic carbon, nitrogen (N) and extractable phosphate (P) and effects on plant richness in ten pairs of grazed ex-fields and neighbouring semi-natural grasslands in different rural landscapes. Each grassland pair where in the same paddock. A multivariate test showed that site location and land use history explained more of differences in species richness than local soil property variables. Plant species richness was positively associated to grazed ex-fields with low pH, low N and P levels. Sites with high plant richness in semi-natural grasslands also had more species in the adjacent grazed ex-fields, compared to sites neighbouring less species-rich semi-natural grasslands. Although both soil properties and species richness were different in grazed ex-fields compared to semi-natural grassland, the site location within a landscape, and vicinity to species-rich grasslands, can override effects of soil properties. In conclusion, if properly located, ex-arable fields may be an important habitat to maintain plant diversity at larger spatio-temporal scales and should considered as potential sites for grassland restoration. [source]


Vegetation correlates of gibbon density in the peat-swamp forest of the Sabangau catchment, Central Kalimantan, Indonesia

AMERICAN JOURNAL OF PRIMATOLOGY, Issue 7 2010
Marie Hamard
Abstract Understanding the complex relationship between primates and their habitats is essential for effective conservation plans. Peat-swamp forest has recently been recognized as an important habitat for the Southern Bornean gibbon (Hylobates albibarbis), but information is scarce on the factors that link gibbon density to characteristics of this unique ecosystem. Our aims in this study were firstly to estimate gibbon density in different forest subtypes in a newly protected, secondary peat-swamp forest in the Sabangau Catchment, Indonesia, and secondly to identify which vegetation characteristics correlate with gibbon density. Data collection was conducted in a 37.1,km2 area, using auditory sampling methods and vegetation "speed plotting". Gibbon densities varied between survey sites from 1.39 to 3.92,groups/km2. Canopy cover, tree height, density of large trees and food availability were significantly correlated with gibbon density, identifying the preservation of tall trees and good canopy cover as a conservation priority for the gibbon population in the Sabangau forest. This survey indicates that selective logging, which specifically targets large trees and disrupts canopy cover, is likely to have adverse effects on gibbon populations in peat-swamp forests, and calls for greater protection of these little studied ecosystems. Am. J. Primatol. 72:607,616, 2010. © 2010 Wiley-Liss, Inc. [source]


Water uptake and nutrient concentrations under a floodplain oak savanna during a non-flood period, lower Cedar River, Iowa,

HYDROLOGICAL PROCESSES, Issue 21 2009
Keith E. Schilling
Abstract Floodplains during non-flood periods are less well documented than when flooding occurs, but non-flood periods offer opportunities to investigate vegetation controls on water and nutrient cycling. In this study, we characterized water uptake and nutrient concentration patterns from 2005 to 2007 under an oak savanna located on the floodplain of the Cedar River in Muscatine County, Iowa. The water table ranged from 0·5 to 2·5 m below ground surface and fluctuated in response to stream stage, plant water demand and rainfall inputs. Applying the White method to diurnal water table fluctuations, daily ET from groundwater averaged more than 3·5 mm/day in June and July and approximately 2 mm/day in May and August. Total annual ET averaged 404 mm for a growing season from mid-May to mid-October. Savanna groundwater concentrations of nitrate-N, ammonium-N, and phosphate-P were very low (mean <0·18, <0·14, <0·08 mg/l, respectively), whereas DOC concentrations were high (7·1 mg/l). Low concentrations of N and P were in contrast to high nutrient concentrations in the nearby Cedar River, where N and P averaged 7·5 mg/l and 0·13, respectively. In regions dominated by intensive agriculture, study results document valuable ecosystem services for native floodplain ecosystems in reducing watershed-scale nutrient losses and providing an oasis for biological complexity. Improved understanding of the environmental conditions of regionally significant habitats, including major controls on water table elevations and water quality, offers promise for better management aimed at preserving the ecology of these important habitats. Copyright © 2009 John Wiley & Sons, Ltd. [source]


The distribution and diversity of amphibian fauna of Lake Nabugabo and surrounding areas

AFRICAN JOURNAL OF ECOLOGY, Issue 2004
M. Behangana
Abstract Six major vegetation types surrounding Lake Nabugabo were sampled for amphibians. These types were: shoreline zone (habitat type code A) representing vegetation on the shoreline about 2 m from the shoreline; Miscanthidium violaceum (B); Eragrostis-Loudetia (C); swamp forest (D); Cyperus papyrus (E); and medium altitude evergreen forest (F). A total of 168 days were spent in the field with a total of 288 1 h counts. Forty-eight counts were carried out in each vegetation type. Sampling was carried out between 17.00 and 24.00 h to coincide with the time amphibians are very active. Twenty-four species were recorded during the study period. These account for about 27.9% of total number of amphibian species recorded in Uganda. Four families were identified, which included: Ranidae (12 spp.), Hyperolidae (8 spp.), Bufonidae (3 spp.) and Pipidae (1 sp.). There was substantial variation in observed species composition among vegetation types. The most species rich habitat was the Eragrostis-Loudetia vegetation zone (17 spp.), followed by the swamp forest zone (14 spp.), then the M. violeceum swamp (11 spp.) and the shoreline (10 spp.). The most species poor sites were C. papyrus swamp (6 spp.) followed by the medium altitude forest (7 spp.). In terms of species abundance, the swamp forest and the M. violecium zones were the most important amphibian habitats for the common species while the Eragrostis-Laudetia zone stood out as the most important for the rare species. From the data collected, it can be deduced that the three most important habitats for the conservation of amphibian fauna in the study area are the Eragrostis-Laudetia, M. violeceum and the swamp forest zones. [source]


Natural avalanche disturbance shapes plant diversity and species composition in subalpine forest belt

JOURNAL OF VEGETATION SCIENCE, Issue 5 2007
Christian Rixen
Abstract Background: Disturbances by avalanches have created unique habitats for animals and plants in subalpine ecosystems worldwide, but at the same time avalanches can pose a major threat to humans. Thus, avalanches are suppressed by means of avalanche barriers to protect settlements and infrastructures in populated areas of the European Alps. As a consequence, the disturbance regime in avalanche tracks has fundamentally changed. Methods: In the present study we address ecological consequences of avalanche suppression on plant diversity. We analysed plant diversity and species composition in recent and old avalanche tracks with and without avalanche suppression and in undisturbed adjacent forests at high and low elevations. Results: The number of species was higher in both active and inactive avalanche tracks as compared to undisturbed subalpine forest. The species composition indicated a wider range of ecological niches in active than in inactive avalanche tracks. The vegetation from active tracks showed lower indicator values for temperature and nitrogen availability. The proportion of alpine species was lower in formerly active tracks. Conclusions: The conditions that exist in active avalanche tracks increase plant diversity in relation to undisturbed forest. In the few decades following avalanche suppression, species composition changes in tracks from which avalanches have been excluded. Continued suppression of avalanche disturbance may lead to a decline in plant and habitat diversity. Avalanche disturbance can exert an important influence on the biodiversity of subalpine forests and provide important habitats. Anthropogenic changes in the natural regime of avalanche disturbance are likely to contribute significantly to future landscape changes in subalpine forests. [source]


Distribution and underground habitats of cave-dwelling bats in China

ANIMAL CONSERVATION, Issue 4 2007
H. Niu
Abstract To understand the distribution and relative abundance of cave-dwelling bats and to identify those sites that would be important for conservation of bat species, 25 underground sites that had not been previously surveyed were investigated in this 3-year study (from December 2003 to April 2006) in Funiu Mountain of Henan province, China. Approximately 80 000 bats were recorded, representing 12 species. The most abundant species were Rhinolophus affinis, Miniopterus schreibersi and Hipposideros pratti. The roosts were evaluated for their conservation importance. The most important sites in the area are Yunhua and Nanzhao caves, which serve as hibernaculums and nursery roosts to c. 13 740 and 11 803 bats, respectively, representing seven species. By means of cluster and correspondence analysis, the distribution of bat species was different between the two sides of the mountain and was highly dependent on the size of the cave. The underground sites in the south region hosted c. 80% of the total bats, representing 11 species. The sites in the north region hosted 20% of the total bats, representing seven species. Presently, none of the caves in the region has adequate protection and some bat populations are under serious threat. Many large caves that contained large bat populations and several species of concern had been developed as tourist sites, and so some advice on protecting the most important local habitats was sought based on the assessment of the conservation status of underground sites. This paper presents basic data concerning the distribution of cave-dwelling bats and the patterns of cave use on Funiu Mountain. The data will help local governments and policy-makers develop suitable strategies to promote local tourisms while protecting important habitats of animal species. [source]