Distribution Patterns Of Plant Species Research Articles

Experiment meets biogeography: plants of river corridor distribution are not more stress tolerant but benefit less from more benign conditions elsewhere

Aims Factors limiting distributions of species are fundamental to ecology and evolution but have rarely been addressed experimentally for multiple species. The conspicuous linear distribution patterns of plant species confined to river corridors in the Central European lowlands constitute an especially long-standing distribution puzzle. We experimentally tested our novel hypothesis that the tolerance of species to river corridor conditions is independent of the degree of confinement to river corridor habitats, but that species not confined to river corridors are better able to take advantage of the more benign non-river corridor conditions. Methods We grew 42 herbaceous species differing in their confinement to river corridors in a common garden experiment on loamy soil typical for river corridor areas and sandy soil typical for non-river corridor areas, and with and without a flooding period. For a subset of species, we grew plants of both river corridor and non-river corridor origin to test for adaptation to river corridor conditions. Important findings Species more confined to river corridor areas benefited less from the more benign non-flooded and non-river corridor soil conditions than species of wider distributional range did. For subsets of 7 and 12 widespread species, the response to flooding and soil origin, respectively, did not differ between plants from river corridor sites and plants from other sites, suggesting that the habitat tolerance of widespread species is due to phenotypic plasticity rather than to local adaptation. Overall, we found clear support for our novel hypothesis that species not confined to river corridors are more able to take advantage of the more benign non-river corridor conditions. Our study provides a general hypothesis on differences between species confined to stressful habitats and widespread species out for test in further multispecies comparative experiments.

Quantitative analysis of sub-alpine grasslands in trans-Himalayan region of Manang, central Nepal

Species composition and richness of grassland vegetation were studied in trans-Himalayan region of Manang. Two south-facing sites, both at the similar altitude (3800-4200 m asl), were selected and a total of 40 plots (10 x 10 m) with 200 quadrates (1 m x 1 m) were sampled. Altogether, 97 plant species were recorded. The similarity index between two sites was 12.37%. There was significant negative correlation between species richness and altitude in site I. Species richness did not show significant relationship with altitude in site II. Various physical and biological factors interact differently in different sites to create habitat heterogeneity which determine the distribution pattern of plant species and influence variations in species composition and diversity. Key-words: alpine region; quantitative analysis; species diversity; vegetation.DOI: 10.3126/botor.v6i0.2910 Botanica Orientalis - Journal of Plant Science (2009) 6: 47-51

Effects of Feces on Spatial Distribution Patterns of Grazed Grassland Communities

Animals excrete feces during grazing. The uneven distribution of feces causes a spatial heterogeneity in grassland communities. In this study, we attempted to clarify the effects of feces on spatial distribution patterns of plant species. A field study was conducted on four grasslands each grazed by a single cow. These four grasslands were defined as Poa pratensis (Kentucky bluegrass) dominated grassland without feces (PoF-), Poa pratensis dominated grassland with feces (PoF+), Zoysia japonica Steud. (Japanese lawngrass) dominated grassland without feces (ZyF-), and Zoysia japonica Steud. dominated grassland with feces (ZyF+). A 50 m line that transects 100 equally spaced quadrats (L-quadrats) was drawn on each of the four grasslands. Each quadrat was 0.50 m ×0.50 m in size and consisted of four equal-area cells of 0.25 m × 0.25 m (S-quadrats). The occurrences of all plant species were recorded in each S-quadrat. The binomial distribution (BD) and beta-binomial distribution (BBD) were used to represent the variation in spatial patterns. The BBD provided a significant description of the frequency distribution of plants per quadrat. A power law was used to calculate the spatial heterogeneity of each species together with the community heterogeneity. The results revealed that the plants on each of the four grasslands were aggregatively distributed. The ZyF+ exhibited greater spatial heterogeneity than the ZyF- due to the uneven deposition of feces by cows grazing on the grasslands. Additionally we also found that the feces had effect on the heterogeneity inZyF+ and did not have effect in PoF+.

Plant species diversity along an altitudinal gradient in Simbalwara wildlife sanctuary, Himachal Pradesh

The composition of forest vegetation along an altitudinal gradient (400 to 650m) in Simbalwara Wildlife Sanctuary was studied during August, 2003. The forest is composed of 53 species of trees, 32 of shrubs and 175 of herbs. The plant communities identified at 400-525m and 525-650m elevation range were Shorea robusta – Mallotus philippensis and Shorea robusta – Terminalia alata respectively. On the basis of importance value index (IVI), Shorea robusta was the dominant tree species at both the elevation ranges. The distribution pattern of plant species was random and contiguous at both the altitudes. The concentration of dominance was lower and index of diversity higher for plant species at both the altitudes Index of diversity for trees was 4.390 and 3.942 at 400-525m and 525-650m elevation range respectively. The index of similarity for trees, shrubs and herbs between two altitudes was 0.64, 0.65 and 0.54 indicating remarkable degree of similarity in plant species. The population structure of tree species is represented mainly by two patterns, one represented by greater proportion of individuals in seedlings stage indicating frequent reproduction and another indicating more individuals in intermediate girth classes with absence of seedlings. If the latter trend continues for longer period, the species may disappear from the area in near future.

Response of pine forest to disturbance of pine wood nematode with interpretative structural model

Pine wood nematode (PWN, Bursaphelenchus xylophilus), originating from North America, causes destructive pine wilt disease. Different pine forest ecosystems have different resistances to B. xylophilus, and after its invasion, the resilience and restoration direction of different ecosystems also varies. In this study, an interpretative structural model was applied for analyzing the response of pine forest ecosystem to PWN disturbance. The result showed that a five-degree multi-stage hierarchical system affected the response of the pine forest ecosystem to PWN disturbance, in which direct affecting factors are resistance and resilience. Furthermore, the analysis to the 2nd, 3rd and 4th degree factors showed that not only does distribution pattern of plant species and pine’s ecological features affect the resistance of pine forests’ ecosystem, but removal of attacked trees and other measures also influence the resistance through indirectly affecting the damage degree of Monochamus alternatus and distribution pattern of plant species. As for resilience, it is influenced directly by soil factors, hydrology, surrounding species provenance and biological characteristics of the second and jointly dominant species, and the climate factors can also have a direct or indirect effect on it by affecting the above factors. Among the fifth elements, the elevation, gradient and slope direction, topographical factors, diversity of geographical location and improvement of prevention technology all influence the response of pine forest ecosystem to PWN disturbance.

Modelling the occurrence of threatened plant species in taiga landscapes: methodological and ecological perspectives

AbstractAim Understanding the spatial patterns of species distribution and predicting the occurrence of high biological diversity and rare species are central themes in biogeography and environmental conservation. The aim of this study was to model and scrutinize the relative contributions of climate, topography, geology and land‐cover factors to the distributions of threatened vascular plant species in taiga landscapes in northern Finland.Location North‐east Finland, northern Europe.Methods The study was performed using a data set of 28 plant species and environmental variables at a 25‐ha resolution. Four different stepwise selection algorithms [Akaike information criterion (AIC), Bayesian information criterion (BIC), adaptive backfitting, cross selection] with generalized additive models (GAMs) were fitted to identify the main environmental correlates for species occurrences. The accuracies of the distribution models were evaluated using fourfold cross‐validation based on the area under the curve (AUC) derived from receiver operating characteristic plots. The GAMs were tentatively extrapolated to the whole study area and species occurrence probability maps were produced using GIS techniques. The effect of spatial autocorrelation on the modelling results was also tested by including autocovariate terms in the GAMs.Results According to the AUC values, the model performance varied from fair to excellent. The AIC algorithm provided the highest mean performance (mean AUC = 0.889), whereas the lowest mean AUC (0.851) was obtained from BIC. Most of the variation in the distribution of threatened plant species was related to growing degree days, temperature of the coldest month, water balance, cover of mire and mean elevation. In general, climate was the most powerful explanatory variable group, followed by land cover, topography and geology. Inclusion of the autocovariate only slightly improved the performance of the models and had a minor effect on the importance of the environmental variables.Main conclusions The results confirm that the landscape‐scale distribution patterns of plant species can be modelled well on the basis of environmental parameters. A spatial grid system with several environmental variables derived from remote sensing and GIS data was found to produce useful data sets, which can be employed when predicting species distribution patterns over extensive areas. Landscape‐scale maps showing the predicted occurrences of individual or multiple threatened plant species may provide a useful basis for focusing field surveys and allocating conservation efforts.

Distribution of plant communities, ecological strategy types and diversity along a moisture gradient

The influence of water regime on the zonation of wetland communities, distribution patterns of plant species, ecological strategies and biodiversity, was studied in this work. Vegetation of the herbaceous wetland was sampled along a transect, in accordance with the standard central European method. Water level was also measured. The changes in plant species composition, plant functional types (ecological strategies, life forms) and diversity were studied. Classification of vegetation releves enabled the definition of five grassland communities. The same pattern remained in DCA ordination also when the species matrix was replaced with a matrix of ecological strategies. Releves were always segregated into distinct plant communities and distributed along the moisture gradient in the same way. Biodiversity is strongly negatively correlated with moisture-it is decreasing with decreasing ground level. Plant ecological strategy types (C-S-R) change significantly along the transect as well. In communities thrivin...

Does the heathland flora in north-western Belgium show an extinction debt?

The large losses of heathland area since the end of the 18th century can be expected to have resulted in the decline or even extinction of many characteristic heathland species. Historical data on plant species distribution patterns can provide valuable information in this context. Therefore, the aims of this research are to study how the loss of heathland area has changed the presence of heathland and forest plant species in north-western Belgium using historical plant distribution data, and to test whether the heathland flora shows an extinction debt. Furthermore, plant traits determining extinction sensitivity are investigated. Our results revealed that, despite the dramatic reduction of heathland area (more than 99% of heathland was destroyed over a 230-year period), the loss of heathland species is relatively limited (11%) and is comparable with that of forest species (11%). Heathland species that have a long-term persistent seed bank or can propagate vegetatively are least sensitive to extinction. For forest species, on the other hand, growth form is the key determinant for extinction sensitivity. Long-lived woody species have a greater chance of persisting. The relatively low extinction numbers probably represent an extinction debt and the full effects of habitat loss may not have been fully manifested yet. Consequently, future extinctions are expected to occur unless environmental conditions are improved. Therefore, heathland restoration and prevention of further heathland area losses is required.

Influence of environmental and spatial variables on regional distribution of forest plant species in a fragmented and changing landscape

During the past several centuries, forests in Europe and large parts of North America have been subject to extensive forest clearance. The last several decades, however, numerous new forest patches have been established onto former agricultural land. As a result, the present forest area often consists of a mixture of small forest patches of different age, area, habitat quality and connectivity embedded within a hostile agricultural landscape. In these patchy landscapes, distribution patterns of plant species may be affected by both regional and local factors, although the relative importance of both is still poorly understood. In this study, we investigated distribution patterns of 113 forest plant species in a fragmented landscape. Species abundances at the regional scale conformed to a clearly unimodal abundance distribution which we believe to be related to 1) environmental heterogeneity due to succession and 2) inequality in migration rates. Patch incidence was significantly related to life form, which in turn was correlated to seed mass and dispersal mechanism. Multiple logistic regressions showed that presence/absence of 59 species studied was significantly affected by patch connectivity, patch area and age for 35, 30 and 34 species, respectively. The results of this study indicate that distribution patterns of forest plant species are influenced by both local and regional factors. Moreover, they also demonstrate that next to spatial aspects of fragmentation, temporal patterns of landscape change may have far‐reaching effects on presence/absence patterns of plant species and therefore should be incorporated in studies dealing with regional population structures of plants.

Testing mutual independence between two discrete-valued spatial processes: a correction to pearson chi-squared.

A common feature of data collected in environmental and earth sciences is that they typically exhibit spatial autocorrelation. Violating the assumption of independent observations can have dramatic effects on inferences derived from standard statistical methods. In this article, we examine the consequences of spatial autocorrelation on Pearson's chi-squared test of mutual independence between two categorical responses with a general number of classes. Correspondingly, we suggest a simple modification to the standard test statistic that allows for spatial autocorrelation. Our modified statistic is based on a first-order correction factor and thus provides only an approximate test. However, we show by Monte Carlo simulation that this approximation results in satisfactory inferences in several situations of practical interest. The usefulness of the method is displayed through an application to categorical data arising in the study of the relationship between the distribution pattern of plant species and woodland age in a forest in northern Belgium.

Habitat configuration, species traits and plant distributions

SummaryIn a metapopulation context, the distribution of a species in a patchy landscape is interpreted as the equilibrium outcome of extinction and colonization processes. Populations are thus more likely to occur in larger, better connected habitat fragments.To test whether metapopulation models explain distribution patterns of plant species with different life histories we investigated the incidence of herbaceous species in deciduous forests in four provinces of south Sweden.These data were correlated with habitat quality (soil pH, nitrogen mineralization and organic matter) and habitat configuration (patch area and distance to the nearest deciduous forest patch). We also examined whether habitat configuration affected the distribution of species with different life history attributes.All ground layer plant species at 81 sites were recorded, and distribution patterns of 57 species were tested against seed mass, seed number, presence of a seed bank, plant height, life span, mode of pollination, dispersal mode and habitat preference.Habitat quality, especially pH, was more important for the incidence of species than habitat configuration with patch area and isolation significantly affecting only 11 and four species, respectively. Species favoured by larger area were also disadvantaged by greater isolation.The importance of habitat configuration to a species varied with life history. Species that were more negatively affected by patch isolation tended to be habitat specialists and clonal perennials and to produce fewer seeds. Animal‐dispersed species were more negatively affected by small stand size.Habitat configuration may be less important for vascular plant distributions than habitat quality or the effects of land use history.

Patterns of plant species distribution in the Trans‐Himalayan region of Ladakh, India

Abstract. We studied the vegetation distribution in eight landscape types distinguished along an altitudinal gradient in the Trans‐Himalayan region of Ladakh, India. The point‐intercept method was used for vegetation sampling. Six plant communities were distinguished by cluster analysis. Of these 6 communities, three communities were dominated by shrub species. Table lands are the landscape type with the highest species diversity followed by undulating areas and river beds. Most plant species were restricted to one landscape type.

Plant distribution patterns related to species characteristics and spatial and temporal habitat heterogeneity in a network of ditch banks

In this study we investigated the relationship between the distribution patterns of a number of herbaceous plant species and the isolation and age of habitat patches. The study was conducted for a network of ditch banks in an agricultural landscape in The Netherlands. Thirteen plant species were selected representing contrasting dispersal and seed bank characteristics. Isolation of habitat patches was determined by the distance to the nearest occupied patch and by the number of occupied patches in circles of increasing radius around the patches. Age was the number of years since the creation of the ditches. In a multiple logistic regression model the separate effects of age of the habitat and the spatial variables were analyzed. A number of habitat variables were used to correct the effect of habitat quality. We concluded that distribution patterns of plant species were mainly determined by habitat quality and the presence of seed sources at short distances (< 25 m). This conclusion was independent of the dispersal characteristics of the species. Most species had higher occupation frequencies in older than younger ditch banks. Only species with persistent seeds had comparable occupation probabilities in older and younger habitat patches, indicating the importance of the soil seed bank as a source of colonization after large-scale disturbances. The effect of age and management on the occupation probabilities of the species was often diminished in the regression model, probably due to correlation between some habitat variables and the age of the patches.

Patterns of plant species distribution in the Trans-Himalayan region of Ladakh, India

Abstract We studied the vegetation distribution in eight landscape types distinguished along an altitudinal gradient in the Trans-Himalayan region of Ladakh, India. The point-intercept method was used for vegetation sampling. Six plant communities were distinguished by cluster analysis. Of these 6 communities, three communities were dominated by shrub species. Table lands are the landscape type with the highest species diversity followed by undulating areas and river beds. Most plant species were restricted to one landscape type. Nomenclature: Kachroo et al. (1977); Polunin & Stainton (1984).

Impact of cattle dung deposition on the distribution pattern of plant species in an alvar limestone grassland

Abstract. Seed banks in cattle dung, soil under cattle dung and soil under vegetation and growth response of plant species to the changes in soil nitrogen availability were studied in an alvar limestone grassland on Öland, Sweden, in order to analyse the impact of dung deposition and decomposition on the formation of patches of plant species. Results suggest that patches of four plant species could result from cattle dung deposition and decomposition. Impact of dung could proceed in three ways: (1) by changing the relative abundance of species in the soil seed bank under dung, and/or (2) by influencing the deposition of seeds in the dung, and/or (3) by intensifying the growth of some species through nutrient release. Species patches could result from one or more of these aspects. For instance, patches of Arenaria serpyllifolia may be induced by dung deposition because of the dominance of its seeds in dung, while the pattern of Cerastium semidecandrum and Festuca ovina may be due to the abundance of their seeds in the soil seed bank under dung and their positive growth response to increased nitrogen availability.

The effects of decreased management on plant-species distribution patterns in a salt marsh nature reserve in the Wadden Sea

To restore natural salt-marsh habitats, maintenance of the artificial drainage system was discontinued and cattle grazing was reduced in man-made salt marshes in the Dollard estuary, the Netherlands. We studied the vegetation development in these marshes shortly after these marshes became a nature reserve, and again 8–9 years later. Cattle distribution showed a gradient of intensive use close to the landward seawall to a low or zero use more seawards. Elymus repens was mainly found at the highest elevations and in the landward parts of the marsh, and lost much of its dominance. Conversely, Aster tripolium increased landwards, and showed a shift to higher marsh elevations. These changes are explained by the interaction between increased soil waterlogging in the marsh, due to the neglect of the drainage system, and cattle grazing. Phragmites australis, Spartina anglica and Scirpus maritimus were mainly found in the seaward parts of the marsh. Spartina anglica and Scirpus maritimus decreased strongly, partly through competitive replacement by Phragmites australis and partly due to herbivory by greylag geese (Anser anser). Bare soil increased in depressions due to increased waterlogging in the marsh combined with livestock grazing and goose grubbing. Phragmites australis probably forms the climax vegetation in the brackish Dollard marshes. Its increase in the seaward parts is irreversible in practice, but will benefit reed-bed breeding birds. On the landward side, the combination of neglect of the drainage system with moderate grazing may be effective in maintaining young successional stages suitable for a wider range of halophytic plants, and for breeding redshank and grazing waterfowl.

Predicting plant species distribution patterns using simple climatic parameters: a case study of Ecuadorian palms

A Geographic Information System (GIS) is used to model plant distributions The model IS based on annual mean temperature, humidity, and a georeferenced specimen data base and predicts potential and probable distribution for each taxa in the data base Potential distribution range is suitable area determined by climatic constraints Probable distribution range is here defined as the pan of the potential range where a taxon is most likely lo be found based on distance to existing collections Gridded estimates of climatic parameters were calculated based on a Digital Elevation Model and data from ca 100 weather stations The palm family in Ecuador was used to demonstrate the model Potential and probable distribution ranges were calculated for each of the 127 Ecuadorian palm species Maps of potential and probable species richness were calculated by overlaying and accumulating individual distribution maps Potential species richness was highest in the Amazon lowland where it reached 60 species and lowest in the higher parts of the Andes and drier parts of the coastal plain The probable species richness followed a similar pattern but was nowhere higher than 47 species The ratio between potential species richness and probable species richness was used to find areas that are insufficiently sampled

Geoecosystems and Landscape Climate – The Approach to Biodiversity on Landscape Scale

In this article biodiversity is discussed from a geoecological point of view. Geoecology, a subdivision of landscape ecology, deals with the mass-energy budget of an environmental system (“geoecosystem”) in landscape scale dimensions. As an introduction same of the main principles and approaches are reviewed. Within the Coordinated Project Biodiversity, the geoecological studies examine the role of environmental heterogeneity which mainly depends on the impact of abiotic ecosystem factors, as a driving force for triggering and maintaining biological diversity. Thereby special emphasis is put on soil–plant relationships. Soils on the steep slopes of the Jurassic mountains have formed in parent material made up of three different quaternary periglacial deposits. This presence of lithological discontinuities accounts for the high spatial variability of soil physical and chemical properties, entailing a scale-dependency of soil–plant interactions. First results from the test site Nenzlinger Weide seem to indicate that small-scale patterns of plant species distribution are mainly controlled by biologieal interactions whereas large-scale patterns are greatly influenced by changing soil properties. Nitrogen was found to be the most sensitive element. Finally first steps are outlined onto a regional analysis of landscape diversity using soil respiration as an indicator.

A study of the origin of central Brazilian forests by the analysis of plant species distribution patterns

The floristic nature of central Brazilian forests, as well as their links to other main forest formations of eastern tropical South America, is assessed by means of multivariate analyses of 106 existing floristic checklists and by the analysis of a series of dot-maps showing the distribution of 55 woody species. Most species of central Brazilian forests seem to conform to two main distribution patterns: (1) species of deciduous and semideciduous forests are dependent essentially on the occurrence of patches of soils of intermediate to high fertility within the cerrado domain and tend to be distributed mostly along a northeast-southwest arch connecting the caatingas to the chaco boundaries; (2) considerable numbers of gallery forest species are dependent on high soil moisture and many appear to link the Amazonian and Atlantic rainforests by crossing the cerrado region in a northwest-southeast route via the dendritic net of gallery forests. Many gallery forest species are habitat generalists, some even occurring in the cerrado vegetation. Nevertheless, significant numbers of gallery endemics are also present. Galleries of the west and north of the Cerrado Province show stronger floristic links to the Amazonian rainforests, while those of the centre and south show stronger affinity with the montane semideciduous forests of southeastern Brazil. Present-day distribution patterns are discussed in the light of the current knowledge of palaeoenvironmental changes in the Neotropics.A natureza florística das florestas do Brasil Central bem como seus laços com outras grandes formaçõs florestais da América do Sul trópico-oriental é avaliada por meio de análises multivariadas de 106 listagens florísticas existentes e pela análise de uma série de mapas de distribuição geográfica de 55 espécies lenhosas. A maioria das espécies das florestas do Brasil Central parece ajustar-se a dois grandes padrões de distribuição: (1) espécies de florestas decíduas e semidecíduas dependem essencialmente da ocorrência de manchas de solos de média a alta fertilidade dentro do domínio dos cerrados e tendem a se distribuir principalmente ao longo de um arco nordeste-sudoeste que conecta as caatingas às fronteiras do chaco; (2) um considerável número de espécies de florestas de galeria depende basicamente de alta umidade no solo e muitas delas parecem distribuir-se das florestas pluviais da Amazônia até as Atlânticas, cruzando a região do cerrado numa rota noroeste-sudeste através da rede dendrítica de florestas de galeria. Muitas espécies de floresta de galeria são generalistas quanto ao habitat, sendo inclusive compartilhadas com os cerrados. Um significativo número, entretanto, é endêmico das florestas de galena. As galerias do oeste e norte da Província do Cerrado mostram uma ligação florística mais forte com as florestas pluviais da Amazônia, ao passo que as do centro e sul mostram uma estreita afinidade com as florestas semideciduas montanas do sudeste brasileiro. Os padrões de distribuição geográfica atuais que emergiram das análises são discutidos sob a luz do presente conhecimento sobre as mudanças paleoambientais nos Neótropicos.

Isolation, Population Size and Extinction: The Classical and Metapopulation Approaches Applied to Vascular Plants along the Dutch Rhine-System

The recent rise of conservation biology has renewed interest in the effects of population size and isolation on population extinction. Empirical evidence for the role of isolation is however scarce, especially in plants. When applying the classical approach, 'associated with the MacArthur-Wilson model, to patterns of plant species distribution there is seldomly a large contribution of isolation, if any. A more promising way would be to analyse extinction and colonization processes in time of separate species, here called the metapopulation approach. In this paper a data set of 143 sites along the Dutch Rhine system is compared between two years (1956 and 1988)