Latest Articles from Vegetation Classification and Survey Latest 12 Articles from Vegetation Classification and Survey https://vcs.pensoft.net/ Fri, 29 Mar 2024 00:37:31 +0200 Pensoft FeedCreator https://vcs.pensoft.net/i/logo.jpg Latest Articles from Vegetation Classification and Survey https://vcs.pensoft.net/ A first syntaxonomic description of the vegetation of the Karstveld in Namibia https://vcs.pensoft.net/article/99045/ Vegetation Classification and Survey 4: 241-284

DOI: 10.3897/VCS.99045

Authors: Ben J. Strohbach, Marianne M. Strohbach

Abstract: Aims: The Karstveld in Namibia has been recognized as an area of high plant diversity. However, this area is also recognised as a hotspot of various forms of degradation including bush encroachment. Minimal baseline data on the composition and diversity of vegetation in this area is available, therefore this paper is a first attempt to rectify this data deficiency. Study area: The Karstveld in Namibia is formed around the Otavi Mountain Range in northern Central Namibia, consisting of strongly karstified carbonate bedrock, rising up to 2000 m a.s.l. The Karstveld includes the Ovambo Basin plains with shallow calcrete soils north of the range, up to the Omuramba Ovambo. Because of orographic effects, the area receives some of the highest rainfall in Namibia, with up to 600 mm per year. Methods: A set of 889 relevés with 868 species was selected from the GVID ID AF-NA-001 database. A partial data set, using trees, shrubs, dwarf shrubs and grasses only, was used for the classification with modified TWINSPAN. The initial result yielded four main groups, according to which the data was split and further classified. Several vegetation types observed during field surveys were not reflected in the classification results; these were refined using Cocktail with known characteristic species. Results: The four main units represented wetlands and grasslands with six associations, a Thornbush savanna – Karstveld transition zone with four associations, Kalahari vegetation with four associations and the Karstveld proper with eight associations. The latter are grouped together as the Terminalietea prunioides, with two orders and three alliances recognised under them. We describe 16 associations according to the ICPN. Conclusions: Although the associations presented in this paper are clearly defined, there exists a high degree of diversity within these. The Karstveld is also extraordinary species rich within the context of the arid to semi-arid Namibian environment. Taxonomic reference: Klaassen and Kwembeya (2013) for vascular plants, with the exception of the genus Acacia s.l. (Fabaceae), for which Kyalangalilwa et al. (2013) was followed. Abbreviations: ga = annual grass; gp = perennial grass; GPS = Global Positioning System, referring to a hand-held ground receiver; hl = herb layer, containing all hemicryptophytes, therophytes and geophytes, but excluding grasses (Poaceae); ICPN = International Code of Phytosociological Nomenclature (Theurillat et al. 2021); MAP = mean annual precipitation; NMS = nonmetric multidimensional scaling (Kruskal 1964); RDL = Red Data List (IUCN Species Survival Commission 2001); s1 = tall shrubs, i.e. multi-stemmed phanerophytes between 1 and 5 m; s2 = short shrubs, i.e. chamaephytes or ‘dwarf shrubs’ below 1 m; SOTER = Global and National Soils and Terrain Digital Database (FAO 1993); t1 = tall trees, > 10 m; t2 = short trees, between 5 and 10 m; t3 = low trees, i.e. single-stemmed phanerophytes between 2 and 5 m; TWINSPAN = Two Way Indicator Species Analysis (Roleček et al. 2009); WGS84 = World Geodetic System, 1984 ensemble.

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Research Paper Tue, 24 Oct 2023 18:28:19 +0300
Dynamics of inselberg landscapes and their adjacent areas in the Sudano-Guinean zone of Benin through remote sensing analysis https://vcs.pensoft.net/article/89746/ Vegetation Classification and Survey 4: 189-202

DOI: 10.3897/VCS.89746

Authors: Ranmi Elsa Denise Ayeko, Sêwanoudé Scholastique Mireille Toyi, Achille Ephrem Assogbadjo, Brice Augustin Sinsin

Abstract: Aims: Land cover change in inselbergs and adjacent areas was studied from 2003 to 2018 in a region facing anthropogenic pressures to assess dynamics and preserve rare endemic species. Study area: Inselbergs and their adjacent areas in the Sudano-Guinean zone of Benin are included in this study. Methods: Land cover classes of inselbergs and adjacent areas were obtained through supervised classification of Sentinel-2 (2018) and Spot 5 (2003) satellite images. A Chi-square test was used to compare protected and unprotected LULC classes of inselbergs, with 10 m spatial resolution. Results: The results showed that forest and woodland decreased respectively from 8.55% to 3.05% and from 17.63% to 4.79% between 2003 and 2018 while tree and shrub savanna, and grassland increased respectively from 6.52% to 9.49% and from 7.60% to 16.69%. Field and fallow increased from 5.57% in 2003 to 26.12% in 2018 and tree plantation from 6.05% to 13.47%. The analysis of spatial comparisons using the chi-square test showed that the presence of inselbergs in a protected area has no significant effect on their land use. Conclusions: Natural vegetation in inselbergs and adjacent areas is being converted into human-made landscapes by farmers. An urgent conservation plan is needed, including awareness campaigns, tree planting, and sustainable forest management. Taxonomic reference: Akoègninou et al. (2006). Abbreviations: DEM = Digital Elevation Model; GCP = Ground Control Point; LULC = Land Use/Land Cover; ROI = Region of Interest; SRTM = Satellite imagery data, Shuttle radar topography mission.

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Research Paper Mon, 24 Jul 2023 15:03:55 +0300
Ecological and structural differentiation of the Sudanian woodlands in the Biosphere Reserve of Pendjari, Benin https://vcs.pensoft.net/article/91126/ Vegetation Classification and Survey 4: 139-165

DOI: 10.3897/VCS.91126

Authors: Eméline S. P. Assèdé, S. S. Honoré Biaou, Hidirou Orou, Madjidou Oumorou, Coert J. Geldenhuys, Paxie W. Chirwa, Brice Sinsin

Abstract: Aims: This study aims to: i) differentiate the plant associations in the Biosphere Reserve of Pendjari (BRP), ii) determine the ecological characteristics of their habitats and iii) present distribution maps on different soil types. Study area: The BRP, located in the Sudanian Zone of Benin. Methods: 202 phytosociological relevés were sampled according to the Braun-Blanquet method within the BRP. Ordination was performed using Detrended Correspondence Analysis to evaluate vegetation patterns. Soil parameters were used to characterize the vegetation types. Results: The numerical analysis of 202 plots and 249 plant species showed two major floristic groups that correlated with a moisture gradient: drylands versus wetlands. The dryland group was a mixture of woodland and shrub savanna, the dominant ecosystems of the study area. The wetland group encompassed species primarily from riparian forest, tree savanna and grass savanna on floodplains. Syntaxonomical analysis of the dryland group showed rocky and gravelly soil associations (Burkeo africanae-Detarietum microcarpi) and soils associated with or without fine gravels (Andropogono gayani-Terminalietum avicennioidis, Andropogono gayani-Senegalietum dudgeonii and Terminalietum leiocarpae). Syntaxonomical analysis of the wetland group showed riparian forest associations on sandy-clay soil (Coletum laurifoliae, Borassetum aethiopi and Hyparrhenio glabriusculae-Mitragynetum inermis) and floodplain associations on silt-clay soil (Terminalio macropterae-Mitragynetum inermis, Brachiario jubatae-Terminalietum macropterae, Sorghastro bipennati-Vachellietum hockii). Conclusions: Eleven new associations were identified in this study. If the distribution of plant associations was determined by different soil properties, the soil humidity would be one of the main ecological factors determining the establishment of plant species and thus plant association development. Taxonomic reference: Akoègninou et al. (2006), Angiosperm Phylogeny Group classification for the orders and families of flowering plants (APG IV, 2016). Abbreviations: BRP = Biosphere Reserve of Pendjari; CBD = Convention on Biological Diversity; CCA = Constrained Correspondence Analysis; DCA = Detrended Correspondence Analysis; GPS UTM = Global Positioning System Universal Transverse Mercator.

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Research Paper Wed, 19 Jul 2023 08:40:00 +0300
Vegetation structure and composition at different elevational intervals in the arid Tankwa Karoo National Park, South Africa https://vcs.pensoft.net/article/86310/ Vegetation Classification and Survey 4: 115-126

DOI: 10.3897/VCS.86310

Authors: Mogamat Igshaan Samuels, Manam Saaed, Shayne Jacobs, Mmoto Leonard Masubelele, Helga Van der Merwe, Lesego Khomo

Abstract: Study area: The study was conducted in the Tankwa Karoo National Park, one of the driest areas in South Africa. Historic overgrazing has resulted in the poor and often degraded state of vegetation in large parts of the Tanqua Karoo region. Aim: This study assessed the spatial variation of vegetation structure and composition in the three main vegetation types namely: Tanqua Karoo (TK), Tanqua Wash Riviere (TWR) and Tanqua Escarpment Shrubland (TES), along an elevational gradient. Method: Using the point intercept survey method, vegetation cover, plant height, species diversity, life forms, proportions of perennials and annuals were examined in 43 sites, widely distributed in these vegetation types. Results: There were 150 vascular plant species belonging to 83 genera and 29 families recorded across all sites. The most diverse vegetation type was TES with 96 species belonging to 61 genera and 26 families. The vegetation structure was comprised mainly of shrubs and dwarf shrubs with a high proportion of leaf and stem succulent species. The mean perennial vegetation cover throughout the study area was 28 and annuals covered 22%, but this cover varied significantly between the vegetation types. The most dominant life forms were chamaephytes, which comprised 64% of all species, with cryptophytes (18%), therophytes (16%) and nanophanerophytes (2%) less abundant. Surveyed sites in the TES showed a clear association with each other but there was an overlap in the species composition and environmental conditions between some TWR and TK sites. This study highlighted the important role of elevation and topography as drivers of vegetation characteristics. Conclusion: The findings from this study can be used as a vegetation baseline to identify and prioritise degraded areas for active restoration in order to limit further degradation. Considering climate change, elevational studies may provide additional insight into species dynamics across landscapes. Taxonomic reference: Plants of Southern Africa Checklist (South African National Biodiversity Institute 2016). Abbreviations: ANOVA = analysis of variance; GPS = Global Positioning System; LFA = Landscape Function Assessment; NDVI = Normalized difference vegetation index; PCA = principal component analysis; PCo-A = principal co-ordinate analysis; TES = Tanqua Escarpment Shrubland; TK = Tanqua Karoo; TKNP = Tankwa Karoo National Park; TWR = Tanqua Wash Riviere.

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Research Paper Fri, 7 Jul 2023 17:00:01 +0300
Plant diversity in traditional agroecosystems of North Morocco https://vcs.pensoft.net/article/86024/ Vegetation Classification and Survey 4: 31-45

DOI: 10.3897/VCS.86024

Authors: Soufian Chakkour, Erwin Bergmeier, Stefan Meyer, Jalal Kassout, Mohamed Kadiri, Mohammed Ater

Abstract: Questions: While globalisation favours intensive yield-maximizing agriculture with cropping practices that entail agrobiodiversity loss, extensive production systems still exist in areas of marginal lands such as in mountainous regions or islands. It is overdue to study such systems, their sustainability and ecology as potential models for decentralized environmentally balanced land-use. For that purpose, we investigated the composition of the wild arable (segetal) flora in traditional thermo- to mesomediterranean cereal-growing agroecosystems of northwestern Morocco. Study area: The Tingitane (Tangier) Peninsula in the Northwest of Morocco. Methods: A sample of 94 relevés was collected in six areas in the foreland of the Rif Mountains. Results: We found 209 species in 150 genera and 41 families, a mean of 22 species per relevé and a Shannon index of 3.04±0.06. A TWINSPAN classification revealed a high level of similarity between the areas, with the plant communities corresponding to the order Brometalia rubenti-tectorum, but also differences in species composition as a result of climatic, soil and land-use effects. Therophytes dominated, but biennial and perennial herbs indicating shallow tillage and fields under fallow were also common. Almost half of the species found were agrestal species (confined to arable fields), and almost a third were apophytes (native species occurring in fields but also in natural habitats). Twenty-nine species (14%) of the segetal flora were regional endemics and six are considered nationally rare. Although there is evidence of recent structural and floristic diversity decline, traditional agroecosystems tend to favour native species including some of particular conservation interest. Conclusions: The traditional agroecosystems of the Rif Mountains fulfil criteria of High Nature Value agriculture but, in view of recent socio-economic change, require support by policy for their maintenance. Taxonomic reference: Euro+Med PlantBase (http://www.europlusmed.org) [accessed 26 Nov 2022]. Syntaxonomic reference: EuroVegChecklist (Mucina et al. 2016). Abbreviations: TWINSPAN = Two Way Indicator Species Analysis.

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Research Paper Tue, 28 Feb 2023 08:15:01 +0200
A vegetation classification and description of Telperion Nature Reserve, Mpumalanga, South Africa https://vcs.pensoft.net/article/85209/ Vegetation Classification and Survey 3: 199-219

DOI: 10.3897/VCS.85209

Authors: Leslie R. Brown, Itumeleng P. Magagula, Alan S. Barrett

Abstract: Aims: This study identified, classified and mapped the different plant communities found on the Telperion Nature Reserve. Study area: Telperion Nature Reserve, Mpumulanga, South Africa. Methods: Using a 1:10,000 aerial photograph, Telperion was delineated into homogenous physiognomic-physiographic units. 294 sample plots (100 m2) were placed in a randomly stratified manner within identified homogenous units. Plant species present in sample plots were recorded and allocated a modified Braun-Blanquet cover abundance scale value. Sample plot data were captured into TURBOVEG and exported for editing, classification and processing in JUICE. A modified TWINSPAN classification was applied to derive a first approximation of the plant communities in a synoptic table that was refined using Braun-Blanquet procedures. Species were manually arranged into groups. Diagnostic, constant and dominant species were statistically determined from the synoptic table. Threshold values for fidelity, frequency and canopy cover were set and a final phytosociological table was produced for describing the plant species composition for the different plant communities. Results: 22 plant communities were identified for Telperion. Five were major communities, 14 were sub-communities and 13 were variants. The five major plant communities were Cyathea dregei–Ilex mitis ravine woodland, Paspalum urvillei–Phragmites australis valley bottom wetland, Diospyros lycioides–Combretum erythrophyllum riparian woodland, Eragrostis curvula–Seriphium plumosum midslope plateau grassland, and Combretum molle–Englerophytum magalismontanum rocky ridge woodland. The plant communities were also described and mapped. Conclusions: The classification, description and mapping of Telperion’s vegetation provides a basis for management decision making about wildlife stocking rates, fire planning, and vegetation management. Findings indicate that Bankenveld vegetation is heterogeneous with a variety of habitats including woodland and grassland components. Telperion has a variety of plant communities and a high plant species diversity, making it a reservoir for plant species and an important conservation area. Taxonomic reference: SA-Plant Checklist-2019–2020, South African National Biodiversity Institute, 2020, Botanical Database of Southern Africa (BODATSA) (http://posa.sanbi.org/) [accessed January 2022]. Abbreviations: BB = Braun-Blanquet; m a.s.l. = metres above sea level; TWINSPAN = Two-way indicator species analysis.

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Research Paper Thu, 3 Nov 2022 08:52:46 +0200
Classification of grasslands and other open vegetation types in the Palaearctic – Introduction to the Special Collection https://vcs.pensoft.net/article/87068/ Vegetation Classification and Survey 3: 149-159

DOI: 10.3897/VCS.87068

Authors: Arkadiusz Nowak, Idoia Biurrun, Monika Janišová, Jürgen Dengler

Abstract: With this editorial, we introduce the Special Collection “Classification of grasslands and other open vegetation types in the Palaearctic”. In searching the Web of Science for classification papers on Palaearctic grasslands, we found 207 studies from 1972–2021, including 106 typical classification works. These studies originated mainly from Europe, with only few from Asia and only one from Northern Africa. While Europe in the 20th century already had a strong tradition in regional classification studies, the launch of a common plot database (European Vegetation Archive, EVA) and a continental syntaxonomic reference list (EuroVegChecklist) have spurred the developments there in recent years. We then introduce the seven articles of the Special Collection. Four of them present regional studies of certain vegetation types, namely spring vegetation (Montio-Cardaminetea) in Grisons, Switzerland, dry grasslands (Festuco-Brometea) of the inneralpine valleys of Austria, montane to subalpine tall-herb vegetation (Mulgedio-Aconitetea) in the Sudetes Mts., Poland, and steppe depressions (Festuco-Brometea and Molinio-Arrhentatheretea) in Southern Ukraine. A new synthesis of the grassland vegetation of Navarre in Spain (all classes, focus on Festuco-Brometea), started with an unsupervised classification and translated it into a hierarchical expert system, while another study provided the first synthesis of the tall-herb vegetation (mainly Ulopteretea prangae) of Tajikistan. Finally, a study based on the GrassPlot database compared fine-grain beta-diversities across open vegetation types of the Palaearctic. Abbreviations: EDGG = Eurasian Dry Grassland Group, EVA = European Vegetation Archive, IAVS = International Association for Vegetation Science, WoS = Web of Science.

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Editorial Fri, 22 Jul 2022 18:00:20 +0300
Fine-grain beta diversity in Palaearctic open vegetation: variability within and between biomes and vegetation types https://vcs.pensoft.net/article/77193/ Vegetation Classification and Survey 2: 293-304

DOI: 10.3897/VCS/2021/77193

Authors: Iwona Dembicz, Jürgen Dengler, François Gillet, Thomas J. Matthews, Manuel J. Steinbauer, Sándor Bartha, Juan Antonio Campos, Pieter De Frenne, Jiri Dolezal, Itziar García-Mijangos, Riccardo Guarino, Behlül Güler, Anna Kuzemko, Alireza Naqinezhad, Jalil Noroozi, Robert K Peet, Massimo Terzi, Idoia Biurrun

Abstract: Aims: To quantify how fine-grain (within-plot) beta diversity differs among biomes and vegetation types. Study area: Palaearctic biogeographic realm. Methods: We extracted 4,654 nested-plot series with at least four different grain sizes between 0.0001 m² and 1,024 m² from the GrassPlot database spanning broad geographic and ecological gradients. Next, we calculated the slope parameter (z-value) of the power-law species–area relationship (SAR) to use as a measure of multiplicative beta diversity. We did this separately for vascular plants, bryophytes and lichens and for the three groups combined (complete vegetation). We then tested whether z-values differed between biomes, ecological-physiognomic vegetation types at coarse and fine levels and phytosociological classes. Results: We found that z-values varied significantly among biomes and vegetation types. The explanatory power of area for species richness was highest for vascular plants, followed by complete vegetation, bryophytes and lichens. Within each species group, the explained variance increased with typological resolution. In vascular plants, adjusted R2 was 0.14 for biomes, but reached 0.50 for phytosociological classes. Among the biomes, mean z-values were particularly high in the Subtropics with winter rain (Mediterranean biome) and the Dry tropics and subtropics. Natural grasslands had higher z-values than secondary grasslands. Alpine and Mediterranean vegetation types had particularly high z-values whereas managed grasslands with benign soil and climate conditions and saline communities were characterised by particularly low z-values. Conclusions: In this study relating fine-grain beta diversity to typological units, we found distinct patterns. As we explain in a conceptual figure, these can be related to ultimate drivers, such as productivity, stress and disturbance, which can influence z-values via multiple pathways. The provided means, medians and quantiles of z-values for a wide range of typological entities provide benchmarks for local to continental studies, while calling for additional data from under-represented units. Syntaxonomic references: Mucina et al. (2016) for classes occurring in Europe; Ermakov (2012) for classes restricted to Asia. Abbreviations: ANOVA = analysis of variance; EDGG = Eurasian Dry Grassland Group; SAR = species-area relationship.

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Research Paper Thu, 30 Dec 2021 18:09:36 +0200
First vegetation-plot database of woody species from Huíla province, SW Angola https://vcs.pensoft.net/article/68916/ Vegetation Classification and Survey 2: 109-116

DOI: 10.3897/VCS/2021/68916

Authors: Francisco M.P. Gonçalves, António V. Chisingui, José C. Luís, Marina F.F. Rafael, José J. Tchamba, Manuel J. Cachissapa, Isaías M.C. Caluvino, Bernardino R. Bambi, José L.M. Alexandre, Magno D.G. Chissingui, Silva K.A. Manuel, Henrique D. Jacinto, Manfred Finckh, Paulina Meller, Norbert Jürgens, Rasmus Revermann

Abstract: Angola is a country in south-central Africa, particularly rich in biodiversity. Despite the efforts recently made to document its biodiversity, there is a need for standardized sampling methods to document and compare the variety of ecosystems and plants occurring in the country. With this database report we aim to document the abundance and diversity of woody species in the woodlands of Huíla province. The database hosts the results of a standardised plot-based vegetation survey, consisting of 448 vegetation plots distributed throughout the 14 municipalities and Bicuar National Park. In total, 40,009 individuals belonging to 44 plant families were recorded and measured, belonging to 193 woody species. Species richness per municipality ranged from 32 to 126. The mean stem diameter (DBH) was 10.9 cm ± 7.5 cm. Small-size classes are increasingly dominated by few species, while the largest trees come from a wider range of species; miombo key-species dominated almost all size classes. Our study represents the first plot-based vegetation survey of any Angolan province and constitutes a useful source of information for conservation and management. Additionally, may constitute a powerful dataset to support future studies on biodiversity patterns and vegetation change over time and facilitate the elaboration of vegetation maps. Taxonomic reference: Checklist of Angolan Plants (Figueiredo and Smith 2008), The African Plant Database (version 3.4.0) and A new classification of Leguminosae (LPWG 2017). Abbreviations: DBH = Diameter at Breast Height; GIVD = Global Index of Vegetation-Plot Databases; LUBA = Acronym of the Herbarium of Lubango

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Long Database Report Thu, 12 Aug 2021 09:59:42 +0300
SWEA-Dataveg: A vegetation database for sub-Saharan Africa https://vcs.pensoft.net/article/64911/ Vegetation Classification and Survey 2: 59-63

DOI: 10.3897/VCS/2021/64911

Authors: Miguel Alvarez, Michael Curran, Itambo Malombe

Abstract: SWEA-Dataveg is a vegetation-plot database collecting observations mainly in sub-Saharan Africa but also open to the rest of the African continent. To date this database contains more than 5,500 plot observations provided by 47 sources (projects, monographs, and articles). While the database is stored in PostgreSQL (including the PostGIS extension), the R-package “vegtable” implements a suitable exchange format. In this article we assess the current content of SWEA-Database and introduce its history and future as a repository of data for syntaxonomic assessments and macroecological research.

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Long Database Report Wed, 5 May 2021 22:55:15 +0300
A new Vegetation-Plot Database for the Coastal Forests of Kenya https://vcs.pensoft.net/article/47180/ Vegetation Classification and Survey 1: 103-109

DOI: 10.3897/VCS/2020/47180

Authors: Maria Fungomeli, Anthony Githitho, Fabrizio Frascaroli, Saidi Chidzinga, Marcus Cianciaruso, Alessandro Chiarucci

Abstract: Biodiversity data based on standardised sampling designs are key to ecosystem conservation. Data of this sort have been lacking for the Kenyan coastal forests despite being biodiversity hotspots. Here, we introduce the Kenyan Coastal Forests Vegetation-Plot Database (GIVD ID: AF-KE-001), consisting of data from 158 plots, subdivided into 3,160 subplots, across 25 forests. All plots include data on tree identity, diameter and height. Abundance of shrubs is presented for 316 subplots. We recorded 600 taxa belonging to 80 families, 549 of which identified to species and 51 to genus level. Species richness per forest site varied between 43 and 195 species; mean diameter between 13.0 ± 9.8 and 30.7 ± 20.7 cm; and mean tree height between 5.49 ± 3.99 and 12.29 ± 10.61 m. This is the first plot-level database of plant communities across Kenyan coastal forests. It will be highly valuable for analysing biodiversity patterns and assessing future changes in this ecosystem. Taxonomic reference: African Plant Database (African Plant Database version 3.4.0). Abbreviations: DBH = diameter at breast height; GIVD = Global Index of Vegetation-Plot Databases; KECF-VPD = Kenyan Coastal Forests Vegetation Plot Database.

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Long Database Report Tue, 16 Jun 2020 23:14:49 +0300
Plant communities and their environmental drivers on an arid mountain, Gebel Elba, Egypt https://vcs.pensoft.net/article/38644/ Vegetation Classification and Survey 1: 21-36

DOI: 10.3897/VCS/2020/38644

Authors: Maged M. Abutaha, Ahmed A. El-Khouly, Norbert Jürgens, Jens Oldeland

Abstract: Aims: Gebel Elba is an arid mountain range supporting biological diversity that is incomparable to any other region of Egypt. This mountain has a vegetation structure and floristic community similar to the highlands of East Africa and the southwestern Arabian Peninsula. We aimed to provide the first classification of the vegetation units on Gebel Elba and identify the environmental factors controlling their distribution. Study area: Wadi Yahmib and its tributaries, which drain the north-western slopes of Gebel Elba, south-eastern Egypt. Methods: On the basis of 169 relevés, we used TWINSPAN to classify the perennial vegetation. We calculated separate GAMs for the deciduous and evergreen species to describe the patterns for each leaf strategy type with elevation. We used CCA to quantify the relationship between the perennial vegetation and the studied environmental factors. To estimate diversity and our sampling strategy, we used rarefaction curves for species richness. Results: We identified seven communities along the elevational gradient of Wadi Yahmib and its tributaries. We found that each community was restricted to a confined habitat depending on its drought resistance ability. Deciduous Vachellia woodland was the main vegetation type on Gebel Elba, while evergreen Olea woodland appeared in small fragments at higher elevations. We analysed the distribution patterns of deciduous and evergreen trees along the elevational gradient. We found a turnover at 500 m, indicating a potential ecotone between the Vachellia and Olea woodlands that was occupied by a Ficus community. CCA revealed the importance of altitude and soil quality in determining the vegetation structure of Gebel Elba. The species richness increased with elevation as a result of reduced stress and increased water availability at the upper wadis. Conclusions: This study identified seven vegetation units in the study area and showed the importance of orographic precipitation, soil quality and the complex topography in determining the habitats. Taxonomic reference: Boulos (2009); names updated according to POWO (2019). Abbreviations: CCA = Canonical Correspondence Analysis; GAM = Generalized Additive Model; TWINSPAN TWINSPAN = Two Way Indicator Species Analysis.

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Research Paper Mon, 4 May 2020 14:53:10 +0300