What drives plant biodiversity in the clay floodplain grasslands of NSW?

2009 ◽  
Vol 31 (3) ◽  
pp. 329 ◽  
Author(s):  
Tom Lewis ◽  
Peter J. Clarke ◽  
Ralph D. B. Whalley ◽  
Nick Reid
Keyword(s):  
Species Richness ◽  
Species Composition ◽  
Soil Type ◽  
Environmental Variables ◽  
Private Property ◽  
Flood Frequency ◽  
Perennial Grasses ◽  
Plant Biodiversity ◽  
South Wales ◽  
Plant Families

An assessment of the relative influences of management and environment on the composition of floodplain grasslands of north-western New South Wales was made using a regional vegetation survey sampling a range of land tenures (e.g. private property, travelling stock routes and nature reserves). A total of 364 taxa belonging to 55 different plant families was recorded. Partitioning of variance with redundancy analysis determined that environmental variables accounted for a greater proportion (61.3%) of the explained variance in species composition than disturbance-related variables (37.6%). Soil type (and fertility), sampling time and rainfall had a strong influence on species composition and there were also east–west variations in composition across the region. Of the disturbance-related variables, cultivation, stocking rate and flooding frequency were all influential. Total, native, forb, shrub and subshrub richness were positively correlated with increasing time since cultivation. Flood frequency was positively correlated with graminoid species richness and was negatively correlated with total and forb species richness. Site species richness was also influenced by environmental variables (e.g. soil type and rainfall). Despite the resilience of these grasslands, some forms of severe disturbance (e.g. several years of cultivation) can result in removal of some dominant perennial grasses (e.g. Astrebla spp.) and an increase in disturbance specialists. A simple heuristic transitional model is proposed that has conceptual thresholds for plant biodiversity status. This knowledge representation may be used to assist in the management of these grasslands by defining four broad levels of community richness and the drivers that change this status.

Densely regenerating coolibah (Eucalyptus coolabah) woodlands are more species-rich than surrounding derived grasslands in floodplains of eastern Australia

2011 ◽  
Vol 59 (5) ◽  
pp. 468 ◽  
Author(s):  
Megan K. Good ◽  
Jodi N. Price ◽  
Peter Clarke ◽  
Nick Reid
Keyword(s):  
Species Richness ◽  
Species Composition ◽  
Woody Plant ◽  
New South ◽  
Soil Condition ◽  
Plant Biodiversity ◽  
Woody Plant Encroachment ◽  
Site Factors ◽  
South Wales ◽  
Eastern Australia

Woody plant encroachment – the conversion of grasslands to tree- or shrub-dominated ecosystems – occurs in rangelands and savannas worldwide. In eastern Australia, coolibah (Eucalyptus coolabah subsp. coolabah Blakely & Jacobs) regenerated densely following floods in the mid 1970s, converting derived grasslands to dense woodlands. We compared soil and groundstorey vegetation attributes of dense coolibah regeneration to adjacent derived grasslands at three grazed sites in the northern riverine plains of New South Wales. Groundstorey species richness and diversity were significantly higher and groundstorey biomass was significantly lower in dense regeneration plots than in derived grassland plots. Soils from dense regeneration had higher C : N and pH, and lower Na than soils from derived grasslands. Although groundstorey species composition differed significantly between derived grasslands and dense regeneration within sites, variation among sites was more pronounced, indicating that site factors influence community composition more than dense regeneration of coolibah. Our findings suggest that, in contrast to other studies of woody plant encroachment, dense regeneration of coolibah does not result in a decrease in plant biodiversity or soil condition.

scholarly journals Environmental filtering and spillover explain multi-species edge responses across agricultural boundaries in a biosphere reserve

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
J. van Schalkwyk ◽  
J. S. Pryke ◽  
M. J. Samways ◽  
R. Gaigher
Keyword(s):  
Species Richness ◽  
Species Composition ◽  
Habitat Quality ◽  
Environmental Variables ◽  
Natural Habitat ◽  
Environmental Filtering ◽  
Biosphere Reserve ◽  
Natural Habitats ◽  
Habitat Specificity ◽  
Induced Changes

Abstract To ensure integrity of protected areas we need to understand how species respond to anthropogenic borders. We investigate, from a metacommunity perspective, the direct and indirect mechanisms by which transformed areas affect distribution patterns of ground-living arthropod assemblages inhabiting an extensive protected area adjacent to fruit orchards in an important biosphere reserve. Arthropods and environmental variables were sampled along transects perpendicular to natural-orchard edges. Influence of distance from orchard boundary, degree of impermeability of the boundary, orchard habitat quality (local scale land-use intensity), and edge-induced changes in local environmental variables on arthropod species richness and composition in non-crop habitats were assessed. Arthropod groups were assessed in terms of habitat fidelity: species associated with natural habitat (stenotopic species), those within crop habitat (cultural species), and those showing no preference for either habitat (ubiquitous species). Spillover resulted in higher cultural species richness near edges, but not higher overall species richness. Environmental filtering was important for stenotopic species composition, which was influenced by edge-induced changes in environmental variables. Ubiquitous species composition was determined by orchard impermeability. Increased orchard habitat quality was associated with higher cultural and ubiquitous species richness. The effects of orchards on assemblages in natural habitats can be variable, but predictable when using species habitat specificity in conjunction with a metacommunity framework. High intensity orchards may act as sink habitats, especially for species that readily disperse between crop and natural habitats. Here we recommend that local buffer strips are > 85 m wide, which will reduce the influence of cultural species spillover on sensitive natural ecosystems.

scholarly journals Effect of environmental and spatial factors on small-sized fish assemblages in a tropical river

2021 ◽  
Vol 51 (2) ◽  
pp. 129-138
Author(s):  
Izaias Médice FERNANDES ◽  
Katiele de Jesus SACOMAN ◽  
José Paulo de FARIAS-NETO ◽  
Hugmar Pains da SILVA ◽  
Jhony VENDRUSCOLO ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Species Richness ◽  
Species Composition ◽  
Environmental Variables ◽  
Fish Assemblages ◽  
Negative Relationship ◽  
Dispersal Limitation ◽  
River Continuum ◽  
Spatial Factors ◽  
Water Characteristics

ABSTRACT The river continuum concept predicts that gradual changes in river geomorphology and hydrology can drive longitudinal changes in aquatic community structure. Accordingly, we evaluated how environmental variables (electrical conductivity, pH, water transparency and water velocity), spatial factors (distance from headwaters and Moran’s eigen vector maps - MEMs), and the presence of dams affect small-sized fish assemblages along a 105-km stretch of the upper Branco River, a tributary in the Madeira River, Amazonas Basin, Brazil. Seine-net based collections were carried out at 15 sites up- and downriver from dams during the 2019 dry season. We captured a total of 4,330 individual fish belonging to three orders, nine families and 26 species (and a hybrid individual). Electrical conductivity and pH were affected by the presence of dams and the distance from headwaters. Species richness and abundance did not vary in response to environmental variables. While species richness showed no significant variation along the sampled river section, abundance showed a negative relationship with distance from headwaters. Species composition varied significantly in response to pH, linear spatial factors and the presence of dams. Our results suggest that change in species composition of small-sized fish assemblages in the upper Branco River occurs due to variation in water characteristics, inherent dispersal limitation, and in response to the presence of dams.

scholarly journals FISH DIVERSITY AND DISTRIBUTION IN THE AKSU RIVER ESTUARY (ANTALYA-TURKEY), IN RELATION TO ENVIRONMENTAL VARIABLES

2016 ◽  
Vol 5 ◽  
pp. 90-98
Author(s):  
Deniz İnnal
Keyword(s):  
Species Richness ◽  
Species Composition ◽  
Fish Assemblage ◽  
Seasonal Changes ◽  
Environmental Variables ◽  
Dominant Species ◽  
Seasonal Pattern ◽  
River Estuary ◽  
Fish Diversity ◽  
Liza Aurata

Seasonal changes in abundance, species composition, and life-style categories of the fish assemblage in a shallow Mediterranean estuary of southwestern Turkey are described. Fishes were sampled monthly by different nets in Aksu River Estuary from October 2006 and March 2008. In total, 3347 individuals from 26 species were captured. Mugil cephalus, Vimba vimba and Liza aurata were the dominant species and comprised over 50% of the total number. The fish comprised 10 marine, 14 freshwater and 2 migrant. The index of species richness, Shannon-wiener diversity, and evenness each showed a consistent seasonal pattern. Canonical correspondance analysis indicated that salinity correlated with the seasonal pattern in the fish assemblage.

scholarly journals The predominant role of soil in determining species composition of fern communities in subtropical coastal forest ecosystems

2019 ◽  
Vol 14 (4) ◽  
pp. 559-575
Author(s):  
Amanda Angélica Carmes ◽  
Michele de Sá Dechoum ◽  
Pedro Fiaschi
Keyword(s):  
Species Richness ◽  
Species Composition ◽  
Atlantic Forest ◽  
Vegetation Structure ◽  
Environmental Variables ◽  
Abiotic Factors ◽  
Canopy Openness ◽  
Vegetation Types ◽  
Edaphic Conditions ◽  
Fern Species

Ferns are an important component in the understorey of tropical forests and their distribution is influenced by several biotic and abiotic factors. At a regional scale, soil characteristics and canopy openness play an important role in fern species composition and richness, as well as in the abundance of individuals. Our objective was to compare the influence of edaphic conditions and vegetation structure on the abundance and distribution of fern communities in Atlantic forest and restinga forest. Our hypotheses were that fern species richness and diversity are higher in Atlantic forest than in restinga due to limiting conditions in this habitat and the composition of fern species in Atlantic forest differs from restinga, especially due to differences in edaphic conditions. A principal coordinates analysis was applied to ordinate sampling units in relation to the environmental variables and a permutational multivariate analysis of variance was used to test that environmental variables did not differ between the two vegetation types. Species richness was compared using rarefaction curves. The influence of abiotic variables in species composition and abundance was verified using canonical correspondence analysis. No differences were observed in species richness, diversity or dominance between vegetation types, although abundance was higher in restinga. Fern communities respond to edaphic conditions and vegetation structure variations between vegetation types, the soil playing a major role. A greater variety of habitats resulting from differences in soil drainage in restinga facilitates the co-existence of species with different ecological tolerance, increasing local diversity and compensating for limiting conditions in restinga.

scholarly journals Bromeliaceae species from coastal restinga habitats, Brazilian states of Rio de Janeiro, Espírito Santo, and Bahia

Check List ◽  
2008 ◽  
Vol 4 (3) ◽  
pp. 234 ◽  
Author(s):  
Luciana Cogliatti-Carvalho ◽  
Thereza Christina Rocha-Pessôa ◽  
André Felippe Nunes-Freitas ◽  
Carlos Frederico Duarte Rocha
Keyword(s):  
Species Richness ◽  
Species Composition ◽  
Environmental Conditions ◽  
Rio De Janeiro ◽  
The State ◽  
Brazilian Coast ◽  
The North ◽  
Plant Families ◽  
Doce River ◽  
Geographic Distribution Pattern

Bromeliaceae is one of the most representative plant families in restinga habitats. We analyzed the species richness and composition of Bromeliaceae in 13 restinga habitats along the Brazilian coast. We found a total of 41 species distributed along the restinga habitats studied. The restinga of Praia do Sul, in the state of Rio de Janeiro, had the highest number of species (15), whereas the restinga of Abaeté, in the state of Bahia, had the lowest (4). Our data are suggestive that the Doce River may represent the limit of distribution for some bromeliad species, with some species occurring only south of that river and others occurring only to the north of it. The differences in Bromeliaceae species composition among restinga habitats probably are not only due to differences in local environmental conditions, but also due to the geographic distribution pattern of each species and to the present degree of disturbance at each restinga.

scholarly journals Disentangling the Ecological Determinants of Species and Functional Trait Diversity in Herb-Layer Plant Communities in European Temperate Forests

Forests ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 552
Author(s):  
Janez Kermavnar ◽  
Lado Kutnar ◽  
Aleksander Marinšek
Keyword(s):  
Species Richness ◽  
Species Composition ◽  
Plant Communities ◽  
Functional Trait ◽  
Forest Stand ◽  
Relative Importance ◽  
Herb Layer ◽  
Bud Bank ◽  
Tree Species Composition ◽  
Stand Characteristics

Forest herb-layer vegetation responds sensitively to environmental conditions. This paper compares drivers of both taxonomic, i.e., species richness, cover and evenness, and functional herb-layer diversity, i.e., the diversity of clonal, bud bank and leaf-height-seed plant traits. We investigated the dependence of herb-layer diversity on ecological determinants related to soil properties, climatic parameters, forest stand characteristics, and topographic and abiotic and biotic factors associated with forest floor structure. The study was conducted in different forest types in Slovenia, using vegetation and environmental data from 50 monitoring plots (400 m2 each) belonging to the ICP Forests Level I and II network. The main objective was to first identify significant ecological predictors and then quantify their relative importance. Species richness was strongly determined by forest stand characteristics, such as richness of the shrub layer, tree layer shade-casting ability as a proxy for light availability and tree species composition. It showed a clear positive relation to soil pH. Variation in herb-layer cover was also best explained by forest stand characteristics and, to a lesser extent, by structural factors such as moss cover. Species evenness was associated with tree species composition, shrub layer cover and soil pH. Various ecological determinants were decisive for the diversity of below-ground traits, i.e., clonal and bud bank traits. For these two trait groups we observed a substantial climatic signal that was completely absent for taxonomy-based measures of diversity. In contrast, above-ground leaf-height-seed (LHS) traits were driven exclusively by soil reaction and nitrogen availability. In synthesis, local stand characteristics and soil properties acted as the main controlling factors for both species and trait diversity in herb-layer communities across Slovenia, confirming many previous studies. Our findings suggest that the taxonomic and functional facets of herb-layer vegetation are mainly influenced by a similar set of ecological determinants. However, their relative importance varies among individual taxonomy- and functional trait-based diversity measures. Integrating multi-faceted approaches can provide complementary information on patterns of herb-layer diversity in European forest plant communities.

Species Composition and Species Richness in the Hetao Irrigation Region Drainage Ditches, Northern China

2013 ◽  
Vol 27 (2) ◽  
pp. 167-177 ◽  
Author(s):  
Yang Zhao ◽  
Xin-rong Li ◽  
Zhi-shan Zhang ◽  
Yi-gang Hu ◽  
Pan Wu
Keyword(s):  
Species Richness ◽  
Species Composition ◽  
Northern China ◽  
Drainage Ditches

Satellite derived maps of pasture growth status: association of classification with botanical composition

1997 ◽  
Vol 37 (5) ◽  
pp. 547 ◽  
Author(s):  
P. J. Vickery ◽  
M. J. Hill ◽  
G. E. Donald
Keyword(s):  
Near Infrared ◽  
Perennial Grass ◽  
Vegetation Indices ◽  
Fast Growth ◽  
Perennial Grasses ◽  
Bayesian Probability ◽  
Cumulative Probability ◽  
Botanical Composition ◽  
South Wales ◽  
Native Pastures

Summary. Spectral data from the green, red and near-infrared bands of Landsat MSS and Landsat TM satellite imagery acquired in mid-spring were classified into 3 and 6 pasture growth classes respectively. The classifications were compared with a site database of botanical composition for the Northern Tablelands of New South Wales to examine the association between spectral growth class and pasture composition. Pastures ranged in composition from unimproved native perennial grasses through semi-improved mixtures of native and naturalised grasses and legumes to highly improved temperate perennial grasses and legumes. For 3 years of MSS data, the fast growth class had a mean botanical composition of about 80% improved perennial grass and 0% native; medium growth class averaged 46% improved perennial grass and 14% native; while the slow growth class had about 60% native and 1% improved perennial grass when averaged over 3 years of MSS data. For the 6 class TM data from a single year, a predictive logistic regression of cumulative probability was developed for percentage of ‘very fast’ growth pixels and ordered 10 percentile categories of improved perennial grass or native grass. Differences in patch characteristics between classes with MSS disappeared with TM reclassified to the same 3 class level. Most probable pasture type was inferred from 3 class MSS and TM data using Bayesian probability analysis. The resulting maps were similar in general appearance but detail was better with the TM data. The pasture growth classification identified highly improved perennial grass pastures and native pastures but sensitivity to intermediate pasture types was poor. Future improvement will come from direct measurement of biophysical characteristics using vegetation indices or inversion of reflectance models.

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