The grasslands and wetlands of the Sekhukhuneland Centre of Plant Endemism, South Africa

Bothalia ◽  
2002 ◽  
Vol 32 (2) ◽  
pp. 211-231 ◽  
Author(s):  
S. J. Siebert ◽  
A. E. Van Wyk ◽  
G. J. Bredenkamp ◽  
F. Du Plessis
Keyword(s):  
Land Use Planning ◽  
Environmental Gradients ◽  
Conservation Status ◽  
Hierarchical Classification ◽  
Community Diversity ◽  
General Description ◽  
Twinspan Classification ◽  
New Syntaxa ◽  
Floristic Data ◽  
Plant Endemism

A hierarchical classification, description, and ecological and floristic interpretations are presented on the vegetation types of the grasslands and wetlands of the Sekhukhuneland Centre of Plant Endemism. Relevés were compiled in 74 stratified random plots. A TWINSPAN classification, refined by Braun-Blanquet procedures, revealed eight associations. 11 subassociations and four variants. Many new syntaxa are described and ecologically interpreted. For each syntaxon. the species richness, endemism and conservation status was determined. The floristic and habitat information, proposed classification, general description and vegetation key are provided to aid future identification of conservation areas, land use planning and further research. An ordination (DECORANA). based on floristic data, confirmed the relationships that exist between plant communities and associated habitats and environmental gradients. Much of the plant community diversity and distribution can be ascribed to a heterogeneous environment, predominantly determined by soil moisture.

scholarly journals Vegetation of the rock habitats of the Sekhukhuneland Centre of Plan Endemism, South Africa

Bothalia ◽  
2003 ◽  
Vol 33 (2) ◽  
pp. 207-228
Author(s):  
S. J. Siebert ◽  
A. E. Van Wyk ◽  
G. J. Bredenkamp ◽  
F. Siebert
Keyword(s):  
Plant Communities ◽  
Land Use Planning ◽  
Environmental Gradients ◽  
Conservation Status ◽  
Hierarchical Classification ◽  
General Description ◽  
Conservation Areas ◽  
Twinspan Classification ◽  
New Syntaxa ◽  
Floristic Data

A hierarchical classification, description, and ecological and floristic interpretations are presented on the vegetation types of the ultramafic rock habitats of the Sekhukhuneland Centre of Plant Endemism. Relevés were compiled in 100 stratified random plots. A TWINSPAN classification, refined by Braun-Blanquet procedures, revealed 17 plant communities, which are classified into 13 associations belonging to four proposed alliances. Many new syntaxa are ecologically interpreted and described. For each syntaxon, the species richness, endemism and conservation status was determined. Much of the plant community distribution can be ascribed to specific habitat preference. The floristic and habitat information, proposed classification, general description and vegetation key are provided to aid future identification of conservation areas, land use planning and research. An ordination (DECORANA) based on floristic data confirmed potential relationships that could exist between the plant communities and associated habitats and environmental gradients.

scholarly journals Semi-arid savanna of the Potlake Nature Reserve and surrounding areas in Sekhukhuneland, South Africa

Koedoe ◽  
2003 ◽  
Vol 46 (1) ◽  
Author(s):  
S.J. Siebert ◽  
M. Matthee ◽  
A.E. Van Wyk
Keyword(s):  
Plant Community ◽  
Plant Communities ◽  
Land Use Planning ◽  
Environmental Gradients ◽  
Conservation Status ◽  
Hierarchical Classification ◽  
General Description ◽  
Surrounding Areas ◽  
Floristic Data ◽  
Semi Arid

A hierarchical classification, description, and ecological and floristic interpretations are presented on the vegetation types of the semi-arid northern savanna of the Sekhukhuneland Centre of Plant Endemism. Relevés were compiled in 47 stratified random plots. A TWINSPAN classification, refined by Braun-Blanquet procedures, revealed eight plant communities, classified as four associations, one of which is subdivided into five sub-associations. For each plant community, the floristic richness, endemism and conservation status was determined. Much of the plant community distribution can be ascribed to environmental factors and anthropogenic disturbance. An ordination (DECORANA), based on floristic data, showed environmental gradients that possibly exist between plant communities and associated habitats. The floristic information, proposed classification, general description and vegetation key, can be used for the identification and monitoring of protected areas, land-use planning, and further conservation research.

scholarly journals Plant communities of the forests, woodlands and thickets in northern KwaZulu-Natal

Koedoe ◽  
1997 ◽  
Vol 40 (1) ◽  
Author(s):  
H.C. Eckhardt ◽  
N. Van Rooyen ◽  
G.J. Bredenkamp
Keyword(s):  
Species Richness ◽  
Random Sample ◽  
Plant Communities ◽  
Environmental Gradients ◽  
Woody Vegetation ◽  
Kwazulu Natal ◽  
Twinspan Classification ◽  
Floristic Data

An analysis of the woody vegetation of northern KwaZulu-Natal is presented. Releves were compiled in 102 stratified random sample plots. A TWINSPAN classification, refined by Braun-Blanquet procedures, revealed 24 plant communities, also referred to as vegetation units. For each of these vegetation units, the species richness was determined. Four associations were identified which have a conservation importance. An ordination (DECORANA), based on floristic data, revealed the position of the syntaxa on environmental gradients.

scholarly journals Temperature and Water Quality-Related Patterns in Sediment-Associated Symbiodinium Communities Impact Symbiont Uptake and Fitness of Juvenile Acroporid Corals

2017 ◽  
Author(s):  
Kate M. Quigley ◽  
Line K. Bay ◽  
Bette L. Willis
Keyword(s):  
Water Quality ◽  
Environmental Gradients ◽  
Critical Role ◽  
Community Diversity ◽  
Experimental Exposure ◽  
Free Living ◽  
Sediment Samples ◽  
Juvenile Corals ◽  
Temperature Regimes ◽  
Environmental Availability

AbstractThe majority of corals acquire their photo-endosymbiont Symbiodinium from environmental sources anew each generation. Despite the critical role that environmental availability of Symbiodinium plays in the potential for corals to acclimate and adapt to changing environments, little is known about the diversity of free-living Symbiodinium communities and how variation in these communities influences uptake and in hospite communities in juvenile corals. Here we characterize Symbiodinium community diversity in sediment samples collected from eight reefs representing latitudinal and cross-shelf variation in water quality and temperature regimes. Sediment-associated Symbiodinium communities were then compared to in hospite communities acquired by A. tenuis and A. millepora juveniles following 11 – 145 days of experimental exposure to sediments from each of the reefs. Communities associated with juveniles and sediments differed substantially, with sediments harbouring four times more unique OTUs than juveniles (1125 OTUs vs. 271). Moreover, only 10.6% of these OTUs were shared between juveniles and sediments, indicating selective uptake by acroporid juveniles. The diversity and abundance of Symbiodinium types differed among sediment samples from different temperature and water quality environments. Symbiodinium communities acquired by juveniles also differed among the sediment treatments, despite juveniles having similar parentage. Moreover, Symbiodinium communities displayed different rates of infection, mortality, and photochemical efficiencies. This study demonstrates that the biogeography of free-living Symbiodinium types found within sediment reservoirs follows patterns along latitudinal and water quality environmental gradients on the Great Barrier Reef. We also demonstrate a bipartite strategy for Symbiodinium uptake by juvenile corals of two horizontally-transmitting acroporid species, whereby uptake is selective within the constraints of environmental availability.

scholarly journals Elevation-related climate trends dominate fungal co-occurrence patterns on Mt. Norikura, Japan

2021 ◽  
Author(s):  
Ying Yang ◽  
Yu Shi ◽  
Dorsaf Kerfahi ◽  
Matthew C Ogwu ◽  
Jianjun Wang ◽  
...  
Keyword(s):  
Network Structure ◽  
Fungal Community ◽  
Environmental Gradients ◽  
Elevation Gradient ◽  
Network Connectivity ◽  
Community Diversity ◽  
Dominant Factor ◽  
Mean Annual Precipitation ◽  
Elevation Gradients ◽  
Occurrence Patterns

AbstractAlthough many studies have explored patterns of fungal community diversity and composition along various environmental gradients, the trends of co-occurrence networks across similar gradients remain elusive. Here, we constructed co-occurrence networks for fungal community along a 2300 m elevation gradient on Mt Norikura, Japan, hypothesizing a progressive decline in network connectivity with elevation due to reduced niche differentiation caused by declining temperature and ecosystem productivity. Results agreed broadly with predictions, with an overall decline in network connectivity with elevation for all fungi and the high abundance phyla. However, trends were not uniform with elevation, most decline in connectivity occurred between 700 m and 1500 m elevation, remaining relatively stable above this. Temperature and precipitation dominated variation in network properties, with lower mean annual temperature (MAT) and higher mean annual precipitation (MAP) at higher elevations giving less network connectivity, largely through indirect effects on soil properties. Among keystone taxa that played crucial roles in network structure, the variation in abundance along the elevation gradient was also controlled by climate and also pH. Our findings point to a major role of climate gradients in mid-latitude mountain areas in controlling network connectivity. Given the importance of the orographic precipitation effect, microbial community trends seen along elevation gradients might not be mirrored by those seen along latitudinal temperature gradients.ImportanceAlthough many studies have explored patterns of fungal community diversity and composition along various environmental gradients, it is unclear how the topological structure of co-occurrence networks shifts across environmental gradients. In this study, we found that the connectivity of the fungal community decreased with increasing elevation, and that climate was the dominant factor regulating co-occurrence patterns, apparently acting indirectly through soil characteristics. Assemblages of keystone taxa playing crucial roles in network structure varied along the elevation gradient and were also largely controlled by climate. Our results provide insight into the shift of soil fungal community co-occurrence structure along elevational gradients, and possible driving mechanisms behind this.Graphic abstract

scholarly journals The phytosociology of the northern section of the Borakalalo Nature Reserve

Koedoe ◽  
1996 ◽  
Vol 39 (1) ◽  
Author(s):  
L.R. Brown ◽  
G.J. Bredenkamp ◽  
N. Van Rooyen
Keyword(s):  
Plant Communities ◽  
Wildlife Management ◽  
Nature Reserve ◽  
Hierarchical Classification ◽  
Management Programme ◽  
Vegetation Map ◽  
Diagnostic Species ◽  
Twinspan Classification ◽  
Ecological Basis

After classifications and descriptions of the southern and western sections of the Borakalalo Nature Reserve were published, a study on the phytosociology of the northern part was initiated. The study is aimed at providing an ecological basis for establishing an efficient wildlife management programme for the reserve. From a TWINSPAN classification, refined by Braun-Blanquet procedures, 15 plant communities, which can be grouped into six major plant communities, were identified. Descriptions of the various plant communities, include diagnostic species, prominent species and less conspicuous species of the tree, shrub, forb and grass strata. A hierarchical classification, description of the plant communities and a vegetation map are presented.

The environmental niche of soil bacterial, archaeal, fungal and protist communities differ along edaphic and topoclimatic gradients in the Alps

2021 ◽  
Author(s):  
Lucie A Malard ◽  
Heidi K Mod ◽  
Nicolas Guex ◽  
Olivier Broennimann ◽  
Erika Yashiro ◽  
...  
Keyword(s):  
Niche Breadth ◽  
Environmental Changes ◽  
Environmental Gradients ◽  
Community Diversity ◽  
Environmental Niche ◽  
Alpha And Beta Diversity ◽  
Niche Concept ◽  
The Alps ◽  
Microbial Groups ◽  
Taxonomic Groups

Abstract BackgroundThe niche concept describes the range of conditions supporting the establishment and persistence of species in the environment. Although widely used in ecology, it has not been often applied to microbes, for which comparative niche analyses are still lacking. Yet, quantifying the niche of microbial taxa is necessary to forecast how taxa and the communities they compose might respond to environmental changes. In this study, we identified important topoclimatic, edaphic, spatial and biotic drivers of the alpha and beta diversity of bacterial, archaeal, fungal and protist communities. Then, we established a method to calculate the niche breadth and position of each taxon along environmental gradients to determine whether microorganisms have distinct environmental niches. ResultsFor all microbial groups, edaphic properties were identified as the most important drivers of both community diversity and composition. Protists presented the largest niche breadths, followed by bacteria and archaea, with fungi displaying the smallest. Niche breadth generally decreased towards environmental extremes, especially along edaphic gradients, suggesting increased specialisation of all microbial taxa in highly selective environments. ConclusionIn this study, we showed that microorganisms have well defined niches, as do macro-organisms, and that these likely drive part of the observed spatial patterns of community variations, but with notable differences among taxonomic groups. Applying the niche concept more widely to microbial ecology should open many novel perspectives, especially to tackle global change challenges.

scholarly journals The Grassland vegetation of Platberg, eastern Free State, South Africa

Koedoe ◽  
2011 ◽  
Vol 53 (1) ◽  
Author(s):  
Robert F. Brand ◽  
Leslie R. Brown ◽  
Pieter J. Du Preez
Keyword(s):  
Species Richness ◽  
Genetic Material ◽  
Hierarchical Classification ◽  
Anthropogenic Influences ◽  
Grassland Vegetation ◽  
Indigenous Plants ◽  
Conservation Implications ◽  
Significant Difference ◽  
Twinspan Classification ◽  
Community Types

Platberg is an inselberg that presents a refuge for indigenous plants and animals. Uncontrolled human access to this area threatens this sensitive ecosystem. The vegetation of Platberg was investigated to obtain an inventory of the different plant species and communities present in this area. A hierarchical classification, a description and an ecological interpretation of the grassland communities of Platberg are presented. A total of 169 sample plots were placed on a stratified random basis within the study area. From a TWINSPAN classification a total of 27 different plant communities, which can be grouped into two major community types, nine communities, 18 sub-communities and six variants, were identified. A significant difference in species richness was found between the two major communities, with the higher-altitude communities having a higher species richness than the communities on the lower-lying slopes. A total of 26 endemic or near endemic Drakensberg Alpine Centre species were recorded. Conservation implications: Anthropogenic influences are felt globally on ecosystems. High-altitude habitats and organisms will be affected first. Inselbergs have high levels of endemic organisms and are reservoirs and refugia for unique genetic material. This grassland plant community survey of Platberg provides valuable information on inselberg ecology for conservation planning.

A preliminary floristic classification of southern and northern Victoria Land vegetation, continental Antarctica

2008 ◽  
Vol 20 (6) ◽  
pp. 553-562 ◽  
Author(s):  
Nicoletta Cannone ◽  
Rodney Seppelt
Keyword(s):  
Plant Communities ◽  
Environmental Gradients ◽  
Similarity Index ◽  
Hierarchical Classification ◽  
Principal Component ◽  
Floristic Composition ◽  
New Classification ◽  
Victoria Land ◽  
Continental Antarctica

AbstractThis paper proposes a new objectively-generated vegetation classification for southern and northern Victoria Land (continental Antarctica) based on the floristic composition of the plant communities. The new classification aims to integrate the existing physiognomic classification of the cryptogamic Antarctic tundra, provide useful data on floristic composition and distribution of the vegetation occurring in southern and northern Victoria Land, and develop a suitable tool allowing easy comparison of syntaxa from different locations. Field data from 26 sites along a latitudinal gradient (72°–77°S) were analysed by a hierarchical classification integrated with multivariate statistics, including indirect ecological information (Principal Component Analysis). Similarity of the identified groups was assessed through the Jaccard similarity index. The new classification is compatible with previous ones and is widely applicable to Victoria Land and includes previous classification. This standardized approach relates plant communities to their floristic composition and provides a basis for relating vegetation composition to environmental gradients and to patterns of vegetation dynamics and succession which are still poorly understood in Antarctica.

Conservation of forest-dwelling arthropod species: simultaneous management of many small and heterogeneous risks

2008 ◽  
Vol 140 (4) ◽  
pp. 510-525 ◽  
Author(s):  
John R. Spence ◽  
David W. Langor ◽  
Joshua M. Jacobs ◽  
Timothy T. Work ◽  
W. Jan A. Volney
Keyword(s):  
Land Use Planning ◽  
Policy Development ◽  
Conservation Status ◽  
Cost Effective ◽  
Species Level ◽  
Classification Systems ◽  
Insect Fauna ◽  
Arthropod Diversity ◽  
Faunal Change ◽  
Arthropod Species

AbstractThe Canadian insect fauna is too inadequately understood to support well-informed assessments about its conservation status; however, the foregoing collection of synthetic papers illustrates potential threats from industrial forestry. Loss of forest species and dramatic changes in forest insect assemblages driven by forestry activities are well illustrated by studies from places where industrial forest management has been more intensive or of longer duration. Improved understanding of how arthropod species are coupled to habitats, especially microhabitats, appears to be central to progress toward their conservation. Studies of arthropods conducted at the species level are most relevant for applied conservation purposes, because only species-level work that is well documented with voucher specimens provides adequate comparative data to document faunal change. Although taxonomic infrastructure required to support such work is seriously under-resourced in Canada, entomologists can help themselves by producing useful modern resources for species identification, by undertaking collaborative biodiversity work that minimizes the split between taxonomists and ecologists, and by supporting incentives for work at the species level. Securing the future of arthropod diversity in Canadian forests through effective policy will require sound regionally defined bases for whole-fauna conservation that mesh with broader land-use planning. Building these will require a practical understanding of how “ecosite”-classification systems relate to arthropod diversity, accurate inventories of the predisturbance forest fauna in all regions, and development of sound monitoring plans designed to both detect faunal change efficiently and identify its drivers. Such monitoring plans should include both baseline inventories and monitoring of designated control areas. In addition, effective biomonitoring efforts will facilitate the development of suites of arthropod indicators, accommodate both seasonal (especially phenological) and annual variation, clarify the relationship between cost-effective samples and reality, and ensure adequate consideration of “rare” species. Return on investment in monitoring will depend on effective preplanned linkage to policy development that can respond to drivers of faunal change in a way that effectively addresses undesired changes.

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