Vegetation Surveys (vegetation + survey)

Distribution by Scientific Domains

Selected Abstracts

Use of the ecological information system SynBioSys for the analysis of large datasets

Joop H.J. Schaminée
Abstract The rapid developments in computer techniques and the availability of large datasets open new perspectives for vegetation analysis aiming at better understanding of the ecology and functioning of ecosystems and underlying mechanisms. Information systems prove to be helpful tools in this new field. Such information systems may integrate different biological levels, viz. species, community and landscape. They incorporate a GIS platform for the visualization of the various layers of information, enabling the analysis of patterns and processes which relate the individual levels. An example of a newly developed information system is SynBioSys Europe, an initiative of the European Vegetation Survey (EVS). For the individual levels of the system, specific sources are available, notably national and regional Turboveg databases for the community level and data from the recently published European Map of Natural Vegetation for the landscape level. The structure of the system and its underlying databases allow user-defined queries. With regard to its application, such information systems may play a vital role in European nature planning, such as the implementation the EU-program Natura 2000. To illustrate the scope and perspectives of the program, some examples from The Netherlands are presented. They are dealing with long-term changes in grassland ecosystems, including shifts in distribution, floristic composition, and ecological indicator values. [source]

TURBOVEG, a comprehensive data base management system for vegetation data

Stephan M. Hennekens
Abstract. The computer software package TURBOVEG (for Microsoft® Windows®) was developed in The Netherlands for the processing of phytosociological data. This package comprises an easy-to-use data base management system. The data bank to be managed can be divided into several data bases which may consist of up to 100 000 relevés each. The program provides methods for input, import, selection, and export of relevés. In 1994, TURBOVEG was accepted as the standard computer package for the European Vegetation Survey. Currently it has been installed in more than 25 countries throughout Europe and overseas. [source]

Wild coffee management and plant diversity in the montane rainforest of southwestern Ethiopia

Christine B. Schmitt
Abstract Coffea arabica occurs naturally in the montane rainforests of Ethiopia, but large areas of these unique forests have been converted to other land-uses. In the remaining forest, wild coffee is managed and harvested with increasing intensity because of rising coffee prices in the world market. This study evaluated the impact of coffee management on wild coffee populations and the forest vegetation as a basis for conservation planning in southwestern Ethiopia. Vegetation surveys and yield assessments were carried out in unmanaged natural forest and in managed semi-forest coffee (SFC) systems. Analyses show that wild coffee density and coffee yields were low in natural forest (max. 15 kg ha,1 year,1). In SFC systems, 30% of the canopy trees and most undergrowth vegetation were removed. This stimulated wild coffee growth and strongly enhanced yields (max. 54 kg ha,1 year,1), but severely disturbed forest structure. Species richness increased by 26% because of an increase in species of ruderal and secondary vegetation; however, species richness and abundance of typical forest species declined. Conservation of the natural forest therefore requires the control of wild coffee management. Wild coffee certification is discussed as one tool to reconcile conservation measures and the interests of local farmers. Résumé Coffea arabica pousse naturellement dans les forêts pluviales de montagne en Ethiopie, mais de grandes superficies de ces forêts uniques ont été transformées pour d'autres usages. Dans la forêt restante, le café sauvage est géré et récolté de façon de plus en plus intense en raison de l'augmentation du prix du café au niveau mondial. Cette étude a évalué l'impact de la gestion des populations sauvages de café, ainsi que la végétation forestière, afin d'établir une base pour la planification de la conservation dans le sud-ouest de l'Ethiopie. Des études de végétation et des évaluations des récoltes ont été réalisées dans une forêt naturelle non gérée et dans des systèmes semi forestiers où les caféiers sont gérés. Les analyses révèlent que la densité des caféiers sauvages et les récoltes de café sont faibles dans la forêt naturelle (max 15 kg ha,1an,1). Dans les systèmes semi forestiers, 30% des arbres de la canopée et la plus grande partie de la végétation en sous-bois ont été enlevés. Cela stimule la croissance des caféiers et augmente fortement les récoltes (max 54 kg ha,1an,1), mais cela perturbe gravement la structure forestière. La richesse en espèces a augmenté de 26%à cause de l'augmentation des espèces dans la végétation rudérale et secondaire; cependant, la richesse et l'abondance des espèces typiquement forestières ont décliné. La conservation de la forêt naturelle exige dès lors le contrôle de la gestion du café sauvage. On discute de la certification du café sauvage comme moyen de réconcilier les mesures de conservation et les intérêts des fermiers locaux. [source]

The use of teak (Tectona grandis) plantations by large mammals in the Kilombero Valley, southern Tanzania

C. Bonnington
Abstract The establishment of plantations is impacting the large mammal populations of the Kilombero Valley, Tanzania. Animal spoors were used as a proxy for activity to determine the influence of teak stand age on mammals. Habitat variables were compared between different aged stands to investigate the relationship between mammal activity and vegetation characteristics. Vegetation surveys found plantation composition to differ with age; with young stands characterized by slender teak trees, limited leaf litter, abundant grass layer and substantial bare ground. Older plantations contained a high leaf litter layer and dead wood, low grass abundance and minimal bare ground. Spoor transects revealed that mammal species number decreased as the teak matured. Of those vegetation variables tested, grass and bare ground abundance explained significantly the variation in species number and in individual species' habitat use between differently aged stands; therefore this habitat use was influenced by the foraging value of the plantation. This study showed that several species (some of which warrant conservation attention, such as elephant) use plantations <6 years old to a greater extent than plantations >6 years. Thus, there is a need for conservation measures, such as wildlife corridors and staggered teak planting to be continued, allowing large mammal movements in the valley. Résumé L'installation de plantations a un impact sur les populations de grands mammifères de la Vallée de Kilombero, en Tanzanie. Les traces des animaux ont été utilisées comme signes d'activité pour déterminer l'influence de l'âge des bosquets de teck sur les mammifères. On a comparé les variables de l'habitat entre des bosquets d'âge différent pour étudier la relation entre l'activité des mammifères et les caractéristiques de la végétation. Des études de la végétation ont montré que la composition des plantations varie avec leur âge : les jeunes plantations sont caractérisées par des troncs de teck plus minces, une litière de feuilles plus restreinte, une couche herbeuse abondante et une partie non négligeable de sol nu. Les plantations plus anciennes présentent une litière de feuilles plus épaisse et du bois mort, peu d'herbes et très peu de sol nu. Les traces ont révélé que le nombre d'espèces de mammifères diminuait quand la plantation vieillissait. Parmi les variables de la végétation testées, l'abondance de l'herbe et la quantité de sol nu expliquaient de manière significative la variation du nombre d'espèces et celle de l'utilisation de l'habitat par chaque espèce en fonction de l'âge des plantations. L'utilisation de cet habitat était donc influencée par la valeur alimentaire de la plantation. Cette étude a montré que plusieurs espèces (dont certaines, comme l'éléphant, garantissent l'attention de la conservation) fréquentent les plantations de moins de six ans plus souvent que celles de plus de six ans. Il faut donc poursuivre les mesures de conservation, comme des corridors pour la faune sauvage et des plantations de teck décalées, qui permettent les déplacements des grands mammifères dans la vallée. [source]

Density estimates of Panamanian owl monkeys (Aotus zonalis) in three habitat types

Magdalena S. Svensson
Abstract The resolution of the ambiguity surrounding the taxonomy of Aotus means data on newly classified species are urgently needed for conservation efforts. We conducted a study on the Panamanian owl monkey (Aotus zonalis) between May and July 2008 at three localities in Chagres National Park, located east of the Panama Canal, using the line transect method to quantify abundance and distribution. Vegetation surveys were also conducted to provide a baseline quantification of the three habitat types. We observed 33 individuals within 16 groups in two out of the three sites. Population density was highest in Campo Chagres with 19.7,individuals/km2 and intermediate densities of 14.3,individuals/km2 were observed at Cerro Azul. In la Llana A. zonalis was not found to be present. The presence of A. zonalis in Chagres National Park, albeit at seemingly low abundance, is encouraging. A longer-term study will be necessary to validate the further abundance estimates gained in this pilot study in order to make conservation policy decisions. Am. J. Primatol. 72:187,192, 2010. © 2009 Wiley-Liss, Inc. [source]

Reversing spontaneous succession to protect high-value vegetation: Assessment of two Scottish mires using rapid survey techniques

Andrew R.G. Large
Abstract. Despite existing management agreements, significant change has occurred on Carnwath Moss and Coladoir Bog, two mire complexes in central and western Scotland. Spontaneous succession has accelerated, resulting in extensive degradation of the mire vegetation on both sites and, in particular, widespread expansion of Calluna vulgaris - and Molinia caerulea -dominated vegetation types. Vegetation surveys across strong gradients of change were conducted with the aim of quantifying the extent of early (desirable) and late (undesirable) successional vegetation on both sites. For each site multivariate analyses of the vegetation data were carried out using TWINSPAN, which clearly differentiated higher quality and degraded surfaces. In management terms percentage Sphagnum cover can act as a useful proxy measure of water level and shrub layer height can also serve as a useful indicator of the degree of degradation. A broad-based, five class condition continuum was developed for the Carnwath Moss site. While such an assessment scheme is a somewhat arbitrary means of allocating mesotope areas to specific condition classes, it is rapid to apply and simple enough to be applied by a range of users. A drawback is that the methodology is data-light in temporal terms and is not a long-term substitute for properly-funded monitoring programmes for important sites. For both mires, recommendations are made for management with the main emphasis being on maintaining water tables at appropriate levels to maximise the floristic diversity of active mires. [source]

Seasonality of modern pollen and sediment deposition in an estuarine context: the Severn Estuary Levels, southwest England,

J. R. L. Allen
Abstract Recent sedimentological and palynological research on subfossil Holocene banded sediments from the Severn Estuary Levels suggested seasonality of deposition, registered by variations in mineral grain-size and pollen assemblages between different parts of the bands. Here we provide data that strengthen this interpretation from sampling of modern sediments and pollen deposition on an active mudflat and saltmarsh on the margin of the Severn Estuary, and comparison with a vegetation survey and contemporary records of climate, river and tidal regimes. The results of grain-size analysis indicate deposition of comparatively coarse-grained silts during the relatively cool and windy conditions of winter and comparatively fine-grained sediments during relatively warm and calm summer months. Pollen analysis demonstrates the significance of long-term storage of pollen grains and fern spores in the estuarine waterbody, superimposed on which seasonal variations in pollen inputs from local and regional vegetation remain detectable. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Iteratio: calculating environmental indicator values for species and relevés

W. J. Holtland
Abstract Question: Is it possible to translate vegetation maps into reliable thematic maps of site conditions? Method: This paper presents a new method, called Iteratio, by which a coherent spatial overview of specific environmental conditions can be obtained from a comprehensive vegetation survey of a specific area. Iteratio is a database application which calculates environmental indicator values for vegetation samples (relevés) on the basis of known indicator values of a limited number of plant species. The outcome is then linked to a digitalized vegetation map (map of plant communities) which results in a spatial overview of site conditions. Iteratio requires the indicator values of a minimum of 10,20% of the species occurring. The species are given a relative weight according to their amplitudes: species with a narrow range are weighted stronger, species with a broad range are weighted weaker. Conclusion: The method presented here enables a coherent assessment of site conditions on the basis of a vegetation survey and the indicator values of a limited number of plant species. [source]

Enhancing a regional vegetation map with predictive models of dominant plant species in chaparral

Janet Franklin
Abstract. Data from more than 900 vegetation plots surveyed in the evergreen shrublands of southern California were used to develop predictions of the distributions of eight dominant shrub species for a 3880 km2 region. The predictions, based on classification tree (CT) models, were validated using independent field data collected during a vegetation survey conducted in the 1930s. Presence and absence were correctly predicted an average of 75% of the time for the eight species. At the same time, these models minimized false positives, so that presence was predicted in the correct proportion of the cases for most species. The areal proportion of the landscape on which the species were predicted to occur was in the same rank order, and of the same magnitude, as their frequency (proportion of plots in which they occurred) within the field data sets. Predictive maps of species presence were overlaid and combined with an existing regional vegetation map. The shrub species ,assemblages' that resulted from this procedure had analogs with vegetation series defined using field data in previous studies. The resulting multiple species map will be used in a landscape simulation model of fire disturbance and succession. [source]

Plant Community Structure and Conservation of a Northern Peru Sclerophyllous Forest

BIOTROPICA, Issue 2 2010
Susan Aragón
ABSTRACT The vegetation near El Bosque Petrificado Piedra Chamana, in the northern Peruvian Andes, is evergreen sclerophyllous forest with significant shrub, epiphyte, and mat components. Important/characteristic genera include Dodonaea, Polylepis, Oreopanax, Oreocallis, Myrcianthes, and the mat-forming orchid Pleurothallis. A vegetation survey including 12 transects and 240 plots in high- and low-grazed areas documented 96 plant species. Compared with low-grazed areas, high-grazed areas had significantly fewer tree species, more herbs, and higher density of individuals. Both grazing categories exhibited high connectedness (as seen in network metrics) and positive biotic associations (nestedness), suggesting facilitation of some species by others, but high-grazed areas showed greater indications of positive associations (as seen in the C-score and V-ratio). These positive biotic associations may relate to the harsh environment and the role of keystone taxa such as Dodonaea viscosa, canopy trees, and mat-forming elements in moderating conditions and promoting species establishment. Only in the low-grazed areas was there any indication of competitive interactions (negative C-score/ less than expected species-pair occurrence). The shift in sign of the C-score, from negative in low-grazed areas to positive in high-grazed areas, indicates a loss of competitive interactions as a factor influencing community structure where grazing pressure is higher. Conservation of the area's natural resources would be advanced by protection of areas where the vegetation structure is more intact, better controls on grazing animals, and identification of development alternatives that would reduce pressure on the area's unique vegetation. Abstract in Spanish is available at [source]

Factors affecting predation by buzzards Buteo buteo on released pheasants Phasianus colchicus

R.E. Kenward
Summary 1Information on the effects of wildlife predation on game and livestock is required to allow improved management of all organisms involved. Monitoring of prey, predators and predation mechanisms each suggests important methods, illustrated here by data from common buzzards Buteo buteo and ring-necked pheasants Phasianus colchicus. 2Location data from 136 radio-tagged common buzzards, together with prey remains from 40 nest areas, records from 10 gamekeepers and vegetation surveys, were used to investigate raptor predation at 28 pens from which pheasants were released in southern England. 3Among 20 725 juvenile pheasants released in 1994,95, gamekeepers attributed 4·3% of deaths to buzzards, 0·7% to owls, 0·6% to sparrowhawks, 3·2% to foxes and 0·5% to other mammals. 4Fresh pheasant remains were found on 7% of 91 visits to buzzard nests, and 8% of radio-tagged buzzards had significantly more association than other buzzards with pheasant pens. 5Predation by buzzards was most likely to be recorded at release pens with little shrub cover, deciduous canopies and a large number of released pheasants. The number of pheasants killed was greatest in large pens with extensive ground cover, and the highest proportion of released pheasants was killed in large pens where few were released. However, only 21% of 55 releases had > 2 pheasant kills per week. 6Radio-tagged buzzards were located most often at pheasant-release pens with open, deciduous canopies. Pens were most likely to be visited by buzzards that had fledged nearby, but the proximity of buzzard nests had little influence on how much predation occurred. 7Only a minority of buzzards associated frequently with pheasant pens, and predation was heavy at only a minority of sites, where pen characteristics and release factors probably made it easy for individual buzzards to kill pheasants. We suggest that the occasional heavy losses could be avoided by encouraging shrubs rather than ground cover in pens, by siting pens where there are few perches for buzzards, and perhaps also by high-density releases. [source]

The feeding ecology and activity budget of proboscis monkeys

Ikki Matsuda
Abstract A group of proboscis monkeys (Nasalis larvatus) consisting of an alpha-male, six adult females, and several immatures was observed from May 2005,2006. We collected over 1,968,hr of focal data on the adult male and 1,539,hr of focal data on the six females in a forest along the Menanggul River, Sabah, Malaysia. Availability and seasonal changes in plant species consumed by the focal monkeys were determined by vegetation surveys carried out across an area of 2.15,ha along 200,500,m trails in riverine forest. A total of 188 plant species were consumed by the focal monkeys. The activity budget of members of our study group was 76.5% resting, 19.5% feeding, and 3.5% moving. Young leaves (65.9%) and fruits (25.9%) accounted for the majority of feeding time. Over 90% of fruit feeding involved the consumption of unripe fruits and in the majority of case both the fruit flesh and seeds were eaten. Although fruit eating was rare in some months, during other times of the year time fruit feeding exceeded the time devoted to young leaves. We found that monthly fruit availability was positively related to monthly fruit eating and feeding activity, and seasonal fluctuations in dietary diversity were significantly affected by fruit eating. These results suggest that fruit availability and fruit-eating behaviors are key factors that influence the activity budget of proboscis monkeys. Earlier assumptions that colobine monkeys are obligate folivores do not apply well to proboscis monkeys and certain other colobines. Our findings may help contribute to a better understanding of the dietary adaptations and feeding ecology of Asian colobines. Am. J. Primatol. 71:478,492, 2009. © 2009 Wiley-Liss, Inc. [source]

Floristic diversity in fragmented Afromontane rainforests: Altitudinal variation and conservation importance

Christine B. Schmitt
Abstract Question: How does the floristic diversity of Afromontane rainforests change along an altitudinal gradient? What are the implications for conservation planning in these strongly fragmented forest areas that form part of the Eastern Afromontane Biodiversity Hotspot? Location: Bonga, southwestern Ethiopia. Methods: Based on evidence from other montane forests, we hypothesized that altitude has an effect on the floristic diversity of Afromontane rainforests in southwestern Ethiopia. To test this hypothesis, detailed vegetation surveys were carried out in 62 study plots located in four relatively undisturbed forest fragments situated at altitudes between 1600 m and 2300 m. Floristic diversity was evaluated using a combination of multivariate statistical analyses and diversity indices. Results: Ordination and indicator species analyses showed gradual variations in floristic diversity along the altitudinal gradient with a pronounced shift in species composition at ca. 1830 m. Upper montane forest (>1830 m) is characterized by high fern diversity and indicator species that are Afromontane endemics. Lower montane forest (<1830 m) exhibits a greater diversity of tree species and a higher abundance of the flagship species Coffea arabica. Conclusions: Our results provide crucial ecological background information concerning the montane rainforests of Ethiopia, which have been poorly studied until now. We conclude that both forest types identified during this study need to be considered for conservation because of their particular species compositions. Owing to the high degree of forest fragmentation, conservation concepts should consider a multi-site approach with at least two protected areas at different altitudinal levels. [source]

Vegetation change in a man-made salt marsh affected by a reduction in both grazing and drainage

Peter Esselink
Abstract. In order to restore natural salt marsh in a 460-ha nature reserve established in man-made salt marsh in the Dollard estuary, The Netherlands, the artificial drainage system was neglected and cattle grazing reduced. Vegetation changes were traced through two vegetation surveys and monitoring of permanent plots over 15 yr after the management had been changed. Exclosure experiments were started to distinguish grazing effects from effects of increased soil waterlogging caused by the neglect of the drainage system. Both vegetation surveys and permanent plots demonstrated a dichotomy in vegetation succession. The incidence of secondary pioneer vegetation dominated by Salicornia spp. and Suaeda maritima increased from 0 to 20%, whereas the late-successional (Phragmites australis) vegetation from 10 to 15%. Grazing intensity decreased towards the sea. The grazed area contracted landward, which allowed vegetation dominated by tall species to increase seaward. Grazing and increased waterlogging interacted in several ways. The impact of trampling increased, and in the intensively grazed parts soil salinity increased. This can probably be explained by low vegetation cover in spring. Framework Ordination, an indirect-gradient-analysis technique, was used to infer the importance of environmental factors in influencing changes in species composition. Many changes were positively or negatively correlated with soil aeration and soil salinity, whereas elevation was of minor importance. Grazing accounted for only a few changes in species frequency. Changes in permanent plots were greater during the first than during the second half of the study period. In exclosures that were installed halfway through the study period, there was a relatively rapid recovery of previously dominant species that had decreased during the first half of the study period. Species richness per unit area in the reserve increased. At the seaward side of the marsh, the altered management allowed succession to proceed leading to establishment of stands of Phragmites australis, whereas on the landward side, the combination of moderate grazing with neglect of the drainage system appeared an effective measure in maintaining habitats for a wider range of halophytic species. [source]

Relationships between fish and supralittoral vegetation in nearshore marine habitats

Tamara N. Romanuk
Abstract 1.This study was conducted to determine whether there were significant differences in the species richness and community composition of fish assemblages in coastal nearshore habitats with differing compositions of supralittoral vegetation. 2.We sampled fish assemblages and conducted supralittoral vegetation surveys at 27 beaches on the west coast of Vancouver Island, British Columbia. Thirteen of the beaches had supralittoral vegetation characteristic of old-growth coastal forests and 14 had been previously subjected to logging or other disturbances. 3.Physical features (e.g. substrate, salinity, etc.) were recorded at each beach to determine whether there were significant associations between supralittoral vegetation and beach characteristics as well as between beach characteristics and fish assemblages. 4.Across all 27 beaches, 1832 individuals of 31 species of nearshore fish were collected, primarily juvenile cottids and salmonids. Mean species richness did not differ between beaches with old-growth versus secondary-growth supralittoral vegetation; however, a higher cumulative number of species was found at beaches with old-growth supralittoral vegetation. 5.Canonical Correspondence Analysis (CCA) showed that beach characteristics and supralittoral vegetation were not significantly associated. Separate CCA for fish associations with beach characteristics and fish associations with supralittoral vegetation explained ,55% of the variance in fish assemblage composition, suggesting that fish assemblage composition is significantly affected by substrate, submerged vegetation, and physico-chemical conditions as well as by the community composition of vegetation in adjacent supralittoral habitats. 6.Specifically, we found associations between supralittoral vegetation and penpoint gunnels (Apodichthys flavidus Girard), tidepool sculpins (Oligocottus maculosus Girard), Pacific staghorn sculpins (Leptocottus armatus Girard), arrow gobies (Clevelandia ios Jordan and Gilbert), shiner perch (Cymatogaster aggregata Gibbons) and kelp perch (Brachyistius frenatus Gill). Juvenile chum (Oncorhynchus keta Walbaum) and coho (Oncorhynchus kisutch Walbaum) salmon were strongly associated with supralittoral vegetation characteristic of mature coastal forests such as mosses and western red cedar (Thuja plicata) suggesting that some nearshore fish species may be affected by processes originating in terrestrial ecosystems. 7.Our results suggest that some nearshore fish species may be affected by removal of supralittoral vegetation. Copyright © 2006 John Wiley & Sons, Ltd. [source]

The ecological barriers to the recovery of bridal creeper (Asparagus asparagoides (L.) Druce) infested sites: Impacts on vegetation and the potential increase in other exotic species

Abstract To protect native biodiversity from environmental weeds, the impacts that these weeds cause need to be known before weed control commences. Asparagus asparagoides (L.) Druce (bridal creeper) (Asparagaceae) is a serious environmental weed and has been selected for biological control in Australia. To predict the responses of plant communities to the control of bridal creeper, a prerelease baseline of the impacts of bridal creeper on native plant communities was undertaken. Plant assemblages in areas invaded by bridal creeper were compared with reference areas that contained little or no bridal creeper. Areas invaded by bridal creeper contained 52% fewer native plant species when compared with nearby reference areas. However, there was no difference in the number of other exotic plant species between areas. Similar trends were found for the germinable seed bank. Although a greater number of exotic species were present in the seed bank compared with the vegetation surveys, there was still no difference between areas with and without bridal creeper. In a glasshouse trial, exotic species germinated more frequently compared with native species. This could indicate that as bridal creeper density decreases following control, exotic species have an advantage over native species when colonizing areas left vacant by bridal creeper. Second, as bridal creeper areas contained reduced native species richness and cover, they may be susceptible to further weed invasion after bridal creeper is removed. Therefore, simply reducing the presence of bridal creeper may not guarantee successful restoration of invaded areas and additional restoration efforts will be needed to ensure the ultimate goal of protecting native biodiversity is reached. [source]