Latest Articles from Vegetation Classification and Survey Latest 3 Articles from Vegetation Classification and Survey https://vcs.pensoft.net/ Fri, 29 Mar 2024 02:18:52 +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
Distribution of graminoids in open habitats in Tajikistan and Kyrgyzstan https://vcs.pensoft.net/article/95767/ Vegetation Classification and Survey 3: 273-286

DOI: 10.3897/VCS.95767

Authors: Sebastian Świerszcz, Grzegorz Swacha, Małgorzata W. Raduła, Sylwia Nowak

Abstract: Aims: Landscapes of Middle Asia are exposed to human influence due to long-lasting pastoral tradition, and now are largely dominated by non-forest vegetation. Graminoids perform key ecosystem functions, and constitute an important feed source for livestock. We studied the distribution patterns of graminoids cover under climatic and grazing pressure gradients in different open vegetation types. Study area: Tajikistan, Kyrgyzstan. Methods: 1,525 vegetation plots representing five open vegetation types (mires, salt marshes, tall-forb communities, pseudosteppes and steppes) were extracted from the Vegetation of Middle Asia Database. We assessed the relative cover of graminoid species in each vegetation type. The importance of mean annual temperature, sum of annual precipitation, aridity and livestock density as drivers of relative cover of graminoids contribution patterns in the five vegetation types were explored with use of polynomial functions and commonality analysis. Results: Open ecosystems of Middle Asia are characterized by different graminoid contributions. The highest relative cover of graminoids was found for steppes, pseudosteppes and mires. Comparison of model fits for relationship between the graminoids cover, climatic parameters and livestock pressure indicated advantage of polynomial models. The best-fitting models for pseudosteppes were for mean annual temperature, Aridity Index and livestock density, for steppes mean annual temperature and Aridity Index, and for salt marshes mean annual temperature. For mires and tall-forb communities, the models showed a poor fit or no effect of the variables studied. Conclusions: Our study shows that climate and livestock pressure have an impact on the contribution of graminoids in open vegetation types, but a general pattern is difficult to describe. Ongoing climate change may influence the share of graminoids in salt marshes, steppes and pseudosteppes. Grazing (with a common effect of climatic factors) is the most important factor influencing graminoids contribution on pseudosteppes, confirming the secondary origin of this vegetation type. Taxonomic reference: The nomenclature of the vascular plants follows Plants of the World Online (POWO 2022) and problematic taxonomic issues were based on The World Flora Online (WFO 2022). Nomenclature of Stipa spp. follows Nobis et al. (2020).

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Research Paper Tue, 20 Dec 2022 18:34:02 +0200
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