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Background: Low altitude Mopaneveld savanna in the northeastern parts of South Africa is generally well conserved. However, extensive copper mining, agricultural practices and urbanisation in the Phalaborwa region prompted research on the possible effects of land-use change on plant community diversity and function. Species diversity measures are usually considered adequate to assess disturbance effects to inform conservation efforts and management practices. However, diversity measures based on species level accounts often limit the outcomes of these studies as this approach fails to quantify how disturbances affect ecosystem functioning when community assembly, and not species diversity alone, is altered by land-use change.Objectives: The aim of this study was to apply both species and functional diversity measures to a data set derived from various land-use types (i.e. areas exposed to strip mining activities, communal farming practices and conservation) in the Phalaborwa region to examine the effects of land-use change on the community ecology of the herbaceous layer.Results: Land-use change, particularly severe top-soil disturbances through strip mining activities, had a significant filtering effect on all measures of species diversity, though functional evenness was maintained across land-use types.Conclusion: These results suggest that, despite initial species loss, this particular savanna ecosystem is buffered against anthropogenic disturbances through functional stability. Indicator species analyses, as well as relationships between plant functional types and land-use change, revealed that forb species are largely responsible for ecosystem stability in areas exposed to anthropogenic disturbances.

Review of: William Bond. 2019, Oxford University Press, Great Clarendon Street, Oxford, OX2 6DP, UK 192 pages, Hardcover, Paperback, Ebook ISBN-13: 978-0198812456DOI:10.1093/oso/9780198812456.001.0001$78 (~ R 1 135, Hardcover); $85 (~R 1 240, Ebook); $46 (~R 660, Paperback)

Fire and herbivory are important natural disturbances in grassy biomes. Both drivers are likely to influence be- lowground microbial communities but no studies have unravelled the long-term impact of both fire and herbiv- ory on bacterial and fungal communities. We hypothesized that soil bacterial communities change through disturbance-induced shifts in soil properties (e.g. pH, nutrients) while soil fungal communities change through vegetation modification (biomass and species composition). To test these ideas, we characterised soil physico- chemical properties (pH, acidity, C, N, P and exchangeable cations content, texture, bulk density, moisture), plant species richness and biomass, microbial biomass and bacterial and fungal community composition and di- versity (using 16S and ITS rRNA amplicon sequencing, respectively) in six long-term (18 to 70 years) ecological research sites in South African savanna and grassland ecosystems. We found that fire and herbivory regimes pro- foundly modified soil physico-chemical properties, plant species richness and standing biomass. In all sites, an increase in woody biomass (ranging from 12 to 50%) was observed when natural disturbances were excluded. The intensity and direction of changes in soil properties were highly dependent on the topo-pedo-climatic con- text. Overall, fire and herbivory shaped bacterial and fungal communities through distinct driving forces: edaphic properties (including Mg, pH, Ca) for bacteria, and vegetation (herbaceous biomass and woody cover) for fungi. Fire and herbivory explained on average 7.5 and 9.8% of the fungal community variability, respectively, compared to 6.0 and 5.6% for bacteria. The relatively small changes in microbial communities due to natural disturbance is in stark contrast to dramatic vegetation and edaphic changes and suggests that soil microbial communities, having evolved with disturbance, are resistant to change. This represents both a buffer to short-term anthropogenic- induced changes and a restoration challenge in the face of long-term changes. Ecological drivers Grassland Next generation sequencing Savanna Soil microbial diversity South Africa

Background: Land-use effects on grassland flora are difficult to predict due to poor understanding of species losses caused by transformation.Objectives: To determine changes in species diversity and composition by comparing transformed with untransformed grassland.Methods: Floristics of paired plots were sampled within 18 transformed sites (representing agricultural and urban land-uses) and neighbouring untransformed grassland.Results: Endemic and threatened species were negatively affected by transformation, particularly species with belowground bud-banks and storage organs. Species composition, with clear shifts in dominant families, was changed by over 90% on average by transformation.Conclusion: Land-use transformation leads to the loss of native species and increased alien invasive species.

International audience

Savannas are commonly described as a vegetation type with a grass layer interspersed with a discontinuous tree or shrub layer. On the contrary, forbs, a plant life form that can include any nongraminoid herbaceous vascular plant, are poorly represented in definitions of savannas worldwide. While forbs have been acknowledged as a diverse component of the herbaceous layer in savanna ecosystems and valued for the ecosystem services and functions they provide, they have not been the primary focus in most savanna vegetation studies. We performed a systematic review of scientific literature to establish the extent to which forbs are implicitly or explicitly considered as a discrete vegetation component in savanna research. The overall aims were to summarize knowledge on forb ecology, identify knowledge gaps, and derive new perspectives for savanna research and management with a special focus on arid and semiarid ecosystems in Africa. We synthesize and discuss our findings in the context of different overarching research themes: (a) functional organization and spatial patterning, (b) land degradation and range management, (c) conservation and reserve management, (d) resource use and forage patterning, and (e) germination and recruitment. Our results revealed biases in published research with respect to study origin (country coverage in Africa), climate (more semiarid than arid systems), spatial scale (more local than landscape scale), the level at which responses or resource potential was analyzed (primarily plant functional groups rather than species), and the focus on interactions between life forms (rather seldom between forbs and grasses and/or trees). We conclude that the understanding of African savanna community responses to drivers of global environmental change requires knowledge beyond interactions between trees and grasses only and beyond the plant functional group level. Despite multifaceted evidence of our current understanding of forbs in dry savannas, there appear to be knowledge gaps, specifically in linking drivers of environmental change to forb community responses. We therefore propose that more attention be given to forbs as an additional ecologically important plant life form in the conventional tree–grass paradigm of savannas.

Herbivores alter plant biodiversity (species richness) in many of the world’s ecosystems, but the magnitude and the direction of herbivore effects on biodiversity vary widely within and among ecosystems. One current theory predicts that herbivores enhance plant biodiversity at high productivity but have the opposite effect at low productivity. Yet, empirical support for the importance of site productivity as a mediator of these herbivore impacts is equivocal. Here, we synthesize data from 252 large-herbivore exclusion studies, spanning a 20-fold range in site productivity, to test an alternative hypothesis—that herbivore-induced changes in the competitive environment determine the response of plant biodiversity to herbivory irrespective of productivity. Under this hypothesis, when herbivores reduce the abundance (biomass, cover) of dominant species (for example, because the dominant plant is palatable), additional resources become available to support new species, thereby increasing biodiversity. By contrast, if herbivores promote high dominance by increasing the abundance of herbivory-resistant, unpalatable species, then resource availability for other species decreases reducing biodiversity. We show that herbivore-induced change in dominance, independent of site productivity or precipitation (a proxy for productivity), is the best predictor of herbivore effects on biodiversity in grassland and savannah sites. Given that most herbaceous ecosystems are dominated by one or a few species, altering the competitive environment via herbivores or by other means may be an effective strategy for conserving biodiversity in grasslands and savannahs globally. Fil: Koerner, Sally E.. University of North Carolina at Greensboro. Department of Biology; Estados Unidos Fil: Smith, Melinda D.. State University of Colorado - Fort Collins; Estados Unidos Fil: Burkepile, Deron E.. University of California; Estados Unidos Fil: Hanan, Niall P.. New Mexico State University; Estados Unidos Fil: Avolio, Meghan L.. University Johns Hopkins; Estados Unidos Fil: Collins, Scott L.. University of New Mexico; Estados Unidos Fil: Knapp, Alan K.. State University of Colorado - Fort Collins; Estados Unidos Fil: Lemoine, Nathan P.. State University of Colorado - Fort Collins; Estados Unidos Fil: Forrestel, Elisabeth J.. University of California at Davis; Estados Unidos Fil: Eby, Stephanie. Northeastern University; Estados Unidos Fil: Thompson, Dave I.. University of the Witwatersrand; Sudáfrica. Kruger National Park. South African Environmental Observation Network. Ndlovu Node. Scientific Services; Sudáfrica Fil: Aguado-Santacruz, Gerardo A.. Tecnológico Nacional de México; México Fil: Anderson, John P.. New Mexico State University; Estados Unidos Fil: Anderson, T. Michael. University Wake Forest; Estados Unidos Fil: Angassa, Ayana. Botswana University of Agriculture and Natural Resources; Sudáfrica. Hawassa University; Etiopía Fil: Bagchi, Sumanta. Indian Institute of Science; India Fil: Bakker, Elisabeth S.. Netherlands Institute of Ecology; Países Bajos Fil: Bastin, Gary. Alice Springs; Australia Fil: Baur, Lauren E.. University of New Mexico; Estados Unidos Fil: Beard, Karen H.. State University of Utah; Estados Unidos Fil: Beever, Erik A.. United States Geological Survey; Estados Unidos. State University of Montana; Estados Unidos Fil: Bohlen, Patrick J.. University of Central Florida; Estados Unidos Fil: Boughton, Elizabeth H.. MacArthur Agroecology Research Center; Estados Unidos Fil: Canestro, Don. University of California; Estados Unidos Fil: Cesa, Ariela. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires; Argentina Fil: Chaneton, Enrique Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentina Fil: Cheng, Jimin. Northwest A&F University; China Fil: D?Antonio, Carla M.. University of California; Estados Unidos Fil: Deleglise, Claire. Université Grenoble Alpes; Francia Fil: Dembélé, Fadiala. Institut de Formation et de Recherche Appliquee; Sudáfrica Fil: Dorrough, Josh. Ecosystem Mangement Science; Austria Fil: Eldridge, David J.. University of New South Wales; Australia Fil: Fernandez Going, Barbara. University of Texas at Austin; Estados Unidos Fil: Fernández Lugo, Silvia. Universidad de La Laguna; España Fil: Fraser, Lauchlan H.. Thompson Rivers University; Canadá Fil: Freedman, Bill. Dalhousie University Halifax; Canadá Fil: García Salgado, Gonzalo. Dalhousie University Halifax; Canadá Fil: Goheen, Jacob R.. University of Wyoming; Estados Unidos Fil: Guo, Liang. Northwest A&F University; China Fil: Husheer, Sean. New Zealand Forest Surveys; Nueva Zelanda Fil: Karembé, Moussa. Université des Sciences; Malí Fil: Knops, Johannes M. H.. Universidad de Nebraska - Lincoln; Estados Unidos Fil: Kraaij, Tineke. Nelson Mandela University; Sudáfrica Fil: Kulmatiski, Andrew. State University of Utah; Estados Unidos Fil: Kytöviita, Minna Maarit. Universidad de Jyvaskyla; Finlandia Fil: Lezama, Felipe. Universidad de la República; Uruguay Fil: Loucougaray, Gregory. Université Grenoble Alpes; Francia Fil: Loydi, Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina Fil: Milchunas, Dan G.. State University of Colorado - Fort Collins; Estados Unidos Fil: Milton, Suzanne J.. South African Environmental Observation Network; Sudáfrica Fil: Morgan, John W.. La Trobe University; Australia Fil: Moxham, Claire. Arthur Rylah Institute for Environmental Research; Australia Fil: Nehring, Kyle C.. State University of Utah; Estados Unidos Fil: Olff, Han. University of Groningen; Países Bajos Fil: Palmer, Todd M.. University of Florida; Estados Unidos Fil: Rebollo, Salvador. Universidad de Alcalá; España Fil: Riginos, Corinna. The Nature Conservancy; Estados Unidos Fil: Risch, Anita C.. Swiss Federal Institute for Forest, Snow and Landscape Research; Suiza Fil: Rueda, Marta. Consejo Superior de Investigaciones Científicas. Estación Biológica de Doñana; España Fil: Sankaran, Mahesh. National Centre For Biological Sciences; India. University of Leeds; Reino Unido Fil: Sasaki, Takehiro. Yokohama National University; Japón Fil: Schoenecker, Kathryn A.. Fort Collins Science Center and Colorado State University; Estados Unidos Fil: Schultz, Nick L.. Federation University; Australia Fil: Schütz, Martin. Swiss Federal Institute for Forest, Snow and Landscape Research; Suiza Fil: Schwabe, Angelika. Universitat Technische Darmstadt; Alemania Fil: Siebert, Frances. North West University; Sudáfrica Fil: Smit, Christian. University of Groningen; Países Bajos Fil: Stahlheber, Karen A.. University of Wisconsin Green Bay; Estados Unidos Fil: Storm, Christian. Universitat Technische Darmstadt; Alemania Fil: Strong, Dustin J.. United States Department of Agriculture. Agriculture Research Service; Estados Unidos Fil: Su, Jishuai. Northwest A&F University; China Fil: Tiruvaimozhi, Yadugiri V.. National Centre for Biological Sciences; India Fil: Tyler, Claudia. University of California; Estados Unidos Fil: Val, James. Office of Environment and Heritage; Australia Fil: Vandegehuchte, Martijn L.. University of Ghent; Bélgica. Swiss Federal Institute for Forest, Snow and Landscape Research; Suiza Fil: Veblen, Kari E.. State University of Utah; Estados Unidos Fil: Vermeire, Lance T.. United States Department of Agriculture. Agriculture Research Service; Estados Unidos Fil: Ward, David. Kent State University; Estados Unidos Fil: Wu, Jianshuang. Lhasa National Ecological Research Station; China Fil: Young, Truman P.. University of California at Davis; Estados Unidos. Mpala Research Centre; Kenia Fil: Yu, Qiang. Chinese Academy Of Agricultural Sciences; China. Institute of Agricultural Resources and Regional Planning; China Fil: Zelikova, Tamara Jane. University Of Wyoming; . University of Wyoming; Estados Unidos

Plant functional traits provide a valuable tool to improve our understanding of ecological processes at a range of scales. Previous handbooks on plant functional traits have highlighted the importance of standardising measurements of traits to improve our understanding of ecological and evolutionary processes. In open ecosystems (i.e. grasslands, savannas, open woodlands and shrublands), traits related to disturbance (e.g. herbivory, drought, and fire) play a central role in explaining species performance and distributions and are the focus of this handbook. We provide brief descriptions of 34 traits and list important environmental filters and their relevance, provide detailed sampling methodologies and outline potential pitfalls for each trait. We have grouped traits according to plant functional type (grasses, forbs and woody plants) and, because demographic stages may experience different selective pressures, we have separated traits according to the different plant life stages (seedlings saplings and adults). We have attempted to not include traits that have been covered in previous handbooks except for where updates or additional information was considered beneficial.

International conservation efforts have ignored the role and importance of historic disturbance regimes, both natural and anthropogenic, in creating and maintaining biodiversity. In this article we focus on historic livelihoods and land uses which we argue can and should be viewed as a type of intermediate ecological disturbance that may increase landscape heterogeneity which is correlated with biological diversity. Using historic swidden in Bhutan as an example, we illustrate how this historic livelihood and land use maintained intermediate ecological disturbances in an otherwise densely forested landscape and increased plant structural heterogeneity, the proportion of early successional plant species, and the availability of forage and browse of importance to wild ungulates and their predators (e.g., tigers). The cessation of swidden in Bhutan and elsewhere alters historic disturbance regimes with potentially profound effects on flora and fauna. We argue that biodiversity conservation requires understanding and building upon ecological disturbance regimes which should include historic livelihoods and land uses. To be realized in practice, this requires not only further ecological study, but addressing the politics of knowledge.

Fuelwood is the principal energy resource for millions of households around the world, yet its use, availability and management remain poorly understood in many areas. We document fuelwood consumption, growth/yield and standing biomass in a Bhutanese village and alpine area used seasonally by villagers where the government is concerned about harvesting in a recently designated national park. Pinus wallichiana was the only fuelwood used in the village and assessments suggest 52 ha could sustain local needs at current consumption levels (54 m3/household/yr). In contrast, Rhododendron aeruginosum was used in the alpine site and at current consumption rates all will be consumed by 2023. Our findings emphasize the need to manage fuelwood based on site-specific consumption, growth and standing biomass criteria rather than single, nation-wide regulations. We provide methods to develop sustainable fuelwood harvesting and forest management guidelines that are applicable to government and community-managed forests in Bhutan and elsewhere.

The hump-back relationship between species diversity and productivity predicts highest species richness at intermediate levels of biomass, and low species numbers in least and most productive habitats. Sodic patches of semi-arid savannas are considered ‘nutrient hotspots’ by producing high-quality forage. The impact of biomass reduction (due to overgrazing) and accumulation (in the absence of herbivores) on herbaceous species richness and diversity is still unknown for these hotspots. We tested the relationship between biomass and herbaceous species richness/diversity in savanna sodic sites across varying biomass levels obtained through different herbivore exclosures. LOWESS and quadratic regression analyses revealed a unimodal species richness/diversity–biomass relationship for biomass

The distinctiveness of Maputaland Woody Grassland lies within its richness of geoxylic suffrutices and herbaceous flora. Since it is well documented in the literature and easy to distinguish from other grassland types, it was possible to confirm a locality of this unique vegetation unit west of Richards Bay, where it probably forms the southernmost outlier population of this vegetation unit in the Indian Ocean Coastal Belt Biome. Phytosociological data obtained from the study area were analysed to identify plant communities and subsequent mapping units. Floristic gradients obtained through ordination techniques revealed the relationship that exists between the Woody Grassland of the study area and the Maputaland Woody Grassland of Sileza Nature Reserve. This confirms the occurrence of Maputaland Woody Grassland at Richards Bay. Two of the plant communities identified from the Richards Bay site are distinctively different, despite previously being lumped together by different authorities as either Kwambonambi Grassland or Maputaland Woody Grassland.

The need to conduct research on the impact of elephant on the environment prompted the construction of exclosures along two of the most important rivers in the Kruger National Park. Scientific research on these exclosures along the Sabie and Letaba rivers addresses how patterns of spatial and temporal heterogeneity of the riparian zone are affected by fire, flood and herbivory. To further assist this research programme, a vegetation survey was conducted at the Nkhuhlu exclosure site along the Sabie River to classify and map the vegetation of the area. This will provide baseline data to assess future changes in vegetation and floristic patterns due to small-scale environmental factors created by the presence/absence of herbivory and fire. Phytosociological data were analysed to identify plant communities and subsequent mapping units. Five plant communities, ten sub-communities and four variants were recognised and described in relation to prevailing soil forms. Differences in species richness, diversity and community structure of the plant communities are clearly articulated. http://www.scielo.org.za/scielo.php?pid=S0075-64582008000100015&script=sci_arttext http://www.koedoe.co.za/index.php/koedoe/article/download/138/738

Rattan, Old World climbing palm, is an extremely valuable nontimber forest product whose canes are gathered for both market and nonmarket uses. I evaluated the effects of harvesting commercial rattan, Calamus zollingeri Becc., on genet survival and ramet demography in two primary forest sites near Lore Lindu National Park in Sulawesi, Indonesia. I monitored 168 permanently marked C. zollingeri genets for 4 years and surveyed random transects for C. zollingeri genet and ramet populations and evidence of cane harvesting in 1996 and 2000. Cane harvesting had no significant effect on genet survival or mean ramet densities. However, current cane extraction rates significantly reduced mean cane lengths and total available cane throughout the area during the study period. Based on observed genet and ramet populations and average cane growth rates of 1.4 m/year, the sustained-yield harvesting potential of C. zollingeri is approximately 101 m and 56 m/ha/year in the two study sites. Although C. zollingeri exhibits life-history traits well suited to sustained-yield harvesting, including production of multiple canes, cane resprouting following harvest, rapid cane growth, and widespread abundance below 1100 m, current harvest rates exceed growth and yield, and supplies of cane are being depleted. Rattan harvesting is widespread in Lore Lindu National Park. Approximately 18% of the park (42,000 ha) is likely subject to intensive and unsustainable extraction of C. zollingeri. Resumen: El ratan, palma trepadora del Viejo Mundo, es un producto forestal no maderable extremadamente valioso cuyas canas son colectadas tanto para usos de mercado como no mercado. Evalue los efectos de la cosecha del ratan comercial, Calamus zollingeri Becc., sobre la supervivencia de genet y demografia de ramulas en dos sitios de bosque primario cerca del Parque Nacional Lore Lindu en Sulawesi, Indonesia. Durante 4 anos monitoree 168 genets de C. zollingeri marcados permanentemente y revise transectos aleatorios en busca de poblaciones de genet y ramulas de C. zollingeri, asi como evidencia de cosecha de canas en 1996 y 2000. La cosecha de canas no tuvo efecto significativo sobre la supervivencia de genets ni las densidades promedio de ramulas. Sin embargo, las tasas de extraccion de cana actuales redujeron significativamente la longitud promedio de las canas y la disponibilidad total de canas en toda el area durante el periodo de estudio. Con base en poblaciones observadas de genets y ramulas y las tasas promedio de crecimiento de canas de 1.4 m/ano, el potencial de cosecha de produccion sostenida de C. zollingeri es de aproximadamente 101m y 56m/ha/ano en los dos sitios estudiados. Aunque C. zollingeri exhibe caracteristicas adecuadas para cosechas de produccion sostenida, incluyendo la produccion de canas multiples, rebrote de canas despues de la cosecha, crecimiento rapido de canas y amplia abundancia debajo de los 1100 m, las tasas de cosecha actuales exceden el crecimiento y produccion, y las reservas de cana se estan agotando. La cosecha de ratan es extensiva en el Parque Nacional Lore Lindu. Es probable que aproximadamente el 18% del parque (42,000 ha) este sujeto a la extraccion intensiva y no sostenible de C. zollingeri.

The biological diversity in traditional agroecosystems and potential diversity loss associated with land use change in upland Crete was investigated. Using transects, plots and point count sampling...

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.

Cutting small trees to float bundles of rattan cane to market is widespread in Indonesia and is purported to adversely affect primary forests and biodiversity conservation. I monitored rattan cane harvesting, tree species used as floater logs, and the locations and volume of floater log cutting in two forest villages adjacent to Lore Lindu National Park in Central Sulawesi, Indonesia for two years. During this period, an average of 135 and 100 tons of commercial rattan cane, primarily Calamus zollingeri, was harvested annually from the two villages, respectively. Floating cane to market required approximately 2350 and 1667 logs (each 3 m in length and 15-20 cm in diameter) or about 1175 and 834 trees annually in the two villages. Eight tree species were regularly used as floater logs and all were light-weight, fast-growing, pioneer species. Floater logs were harvested from fallowed shifting cultivation fields and naturally disturbed riparian flood plains. Over the two year study period, there was little floater log cutting in primary forests either inside or outside of the national park. The use of early successional tree species to float rattan to market does not appear to adversely affect primary forests or protected area management in this region.

This study documents the abundance, distribution and knowledge of medicinal plant species in a Ransa Dayak village and adjoining forest in West Kalimantan, Indonesia. Over 250 medicinal plant species from 165 genera and 75 families are utilized by the local healer. Late successional, primary and river bench forests contained the highest diversity of locally-utilized medicinal species and the greatest number of species restricted to a single forest type for which alternative species or remedies were unavailable. Epiphytes and trees restricted to primary forests are particularly important sources for plants used to treat unusual ailments. A 100% survey of village residents 15 years of age and older (N = 32) revealed that people older than 25 years of age, and older females in particular, possessed greater knowledge of medicinal plants and their uses than younger people and males. All residents, except the male healer, were more knowledgeable about medicinal plants found in early successional forests than those of primary forests. Commercial logging and the loss of traditional knowledge through acculturation pose twin challenges to the persistence of traditional medicinal plant use in this Ransa village and throughout much of Kalimantan.

Understanding relationships between large herbivores and plant species diversity in dynamic riparian zones is critical to biodiversity conservation. The Nkuhlu exclosures in the Kruger National Park (KNP) provided opportunity to investigate spatial heterogeneity patterns within riparian zones, as well as how these patterns are affected by fire and herbivory. A monitoring project was initiated to answer questions about the dynamics of the herbaceous layer and was aimed at determining, (1) whether there exists meaningful variance in herbaceous plant species richness and diversity across different treatments in the ecologically sensitive sodic zone and (2) whether an increase in herbaceous biomass, an artefact of herbivory and fire exclusion, suppresses herbaceous plant species diversity and richness. Herbaceous vegetation was sampled in two 1 m2 circular sub-plots in the eastern and western corners of 81 fixed plots. The biomass of each plot was estimated with a disc pasture meter (DPM) diagonally with the plot. DPM-readings were converted to kg/ha, according to the latest conversions for the Lowveld Savanna. Species richness and biomass showed significant variance across treatments, whereas no significant variation in herbaceous species diversity was perceived. Combined treatment of fire absence and herbivore presence contributed to higher forb species richness in the sodic zone. Biomass is significantly higher in fully fenced areas where herbivores are excluded, as opposed to the open and partially fenced areas. Although no significant variation was recorded for diversity across treatments, lowest diversity was recorded in the absence of all herbivores, especially in combination with fire treatment. Therefore herbivores are essential in sustaining herbaceous plant species richness in the sodic zone, whilst no significant results were found with regard to their effect on species diversity. Although statistically non-significant, fire seems to suppress species richness.Conservation implications: This study could be used as framework to advance and develop science-based management strategies for, at least, the sodic zones of the KNP. Research in these exclosures will create better understanding of these landscapes, benefit ecosystem conservation planning of national parks and also provide valuable long-term information on key ecological processes.

Calamus exilis and C. zollingeri are coppicing, clustering rattans that possess characteristics favorable to sustained‐yield cane harvesting in protected areas, including high population densities, year‐round cane availability, minimal adverse effects on other species when harvested, well‐developed trade networks, and strong market demand. Cane resprout and growth rate studies suggest that C. exilis can be repeatedly harvested at four year intervals; a longer, but as yet undetermined interval would be required for repeated C. zollingeri harvesting. Although ecological and economic aspects of C. exilis and C. zollingeri appear promising, sustainable harvesting by local people faces significant social and political constraints, including ill‐defined resource access and tenure arrangements, the absence of local village management organizations and harvesting guidelines, and weak political and economic power of rattan collectors and villages vis a vis outside commercial interests.

Reseach was done on the Sodics of the Nkuhlu long-term monitoring exclosures.Variation in different plant characteristics were analised across different treatments over time. No significant variation in morphological types could be detected.

Die groot vloede wat in die jaar 2000 in die Kruger Nasionale Park plaasgevind het, het die rivieroewerplantegroei versteur. Dit het die geleentheid gebied om heinings op te rig langs die Sabierivier om herbivore uit sekere gebiede uit te sluit en sodoende die herstel van die rivieroewerekosisteme te monitor.

The construction of exclosures along two of the most important rivers in the Kruger National Park was done to investigate how patterns of spatial and temporal heterogeneity of the riparian zone is affected by fire, flood and herbivory. To assist this research programme, vegetation surveys were conducted within exclosures along the Letaba River to classify and map the vegetation of the area. The history and experimental design of the Letaba exclosures are similar to that of the Nkhuhlu exclosures along the Sabie River, which is directly related to questions surrounding elephant management. The main difference between the Nkhuhlu and Letaba exclosures is local heterogeneity, since the latter lies within the Mopaneveld, which is floristically and physiognomically much more homogenous than the vegetation of the southern Kruger National Park. Nevertheless, four plant communities, eight sub-communities and six variants were recognised and mapped for the Letaba exclosures. The vegetation description was done in relation to prevailing soil forms, differences in species richness, diversity and community structure, and therefore should serve as a basis for further detailed and broad-based botanical studies. Vegetation mapping was done to sub-community level and, where possible, to variant level. As expected in Mopaneveld vegetation, the plant communities could broadly be related to soil types, although smaller-scale variations correspond to soil moisture availability because the Mopaneveld is considered ‘event-driven’, especially in the herbaceous layer.Conservation implications: Floristic surveying and vegetation mapping of a long-term monitoring site, such as the Letaba exclosures, is seen as a baseline inventory to assist natural resource management. Linking mapping units to biodiversity strengthens the understanding needed to maintain biodiversity in all its natural facets and fluxes.

A classification of the woody component of the riparian vegetation of Zululand coastal thornveld is analysed using the height classes of different woody species as an indication of age. A total of 43 randomly stratified plots was selected using aerial photographs to include all the different plant communities in this rare and endemic vegetation type. A floristic survey of the woody component was conducted within each sample plot. Species data recorded included tree cover and tree richness. Environmental data recorded included altitude, soil type, soil chemistry, aspect and slope. The data set was analysed with TWINSPAN and four woody-plant assemblages were identified. An ordination using CANOCO was applied to examine the relationships between species distribution and associated environmental gradients. Changes in the species composition of woody assemblages occurred along an environmental gradient determined by soil properties and past land use.

Introduction Soil erosion is a major environmental problem that threatens world food production (UNEP, 1980; Dudal, 1981; Kovda, 1983). In the world today not only is the total population being fed greater than ever before in history, but more humans are malnourished (Swaminathan, 1983). At present, one thousand million people are malnourished and the problem is growing rapidly in severity (Latham, 1984). Many changes have occurred since the early 1900s when most nations were self-sufficient in food. Today, the great majority of the world's 183 nations are major food importers (FAO, 1983), underscoring a growing disparity in food resources (Swaminathan, 1983). The food supply problem has persisted, ‘and in some cases worsened despite an increased pace of development’ (Latham, 1984). Given these ominous trends, the control of soil erosion for a sustainable agricultural system is essential to any program to improve world food security and development. Adequate food supplies depend on productive land. At present 97% of the food supply comes from land and only 3% from the oceans and other aquatic systems (CEQ, 1980). Hence, we must safeguard the productivity of the land to feed the ever-increasing world population. Just at a time when agricultural efforts are focused on increasing crop yields, land degradation is increasing throughout the world. Global dimensions of land destruction are alarming. About 35% of the earth's land surface is affected (Mabbutt, 1984).

Relationships between soil erosion on hillside farms and forest conversion to farmland in adjacent national parks were examined in the Bayhang watershed near Leyte Mountains National Park, Philippines, and the Sungai Ning watershed near Kerinci- Seblat National Park, Indonesia. A random sample of hillside farms revealed widespread evidence of accelerated soil erosion in both watersheds, including splash and sheet erosion, and rill and gully formation. Erosion under line transects and on enclosed runoff plots revealed mean soil losses of 422 t/ha during the first six months of cultivation on recently cleared farms in Bayhang and 3.8 t/ha during the cropping year on continuously cultivated farms in Sungai Ning. Analysis of eroded sediments and uneroded soils revealed erosion-induced reductions in soil productivity. Soil erosion and land degradation were found to contribute to forest conversion in both national parks. The farmers' response to land degradation in Bayhang was to clear forest for new farms in Leyte Mountains National Park, while farmers in Kerinci replaced nutrient-demanding crops with cassava, and cleared forest for new farms in Kerinci-Seblat National Park. Potentially sustainable and appropriate soil conservation and economic development activities for use in the two watersheds are reviewed.

Forest-product use among nonforest dwelling cultural groups in Southeast Asia is not well known, particularly in contrast to what is known about indigenous forest-product collectors. A case study in one lowland Filipino village in Leyte, Philippines, revealed that over half of village households depend upon 8 species of commercially valuable rattan and 8 species of timber as a primary source of livelihood, and that all village households collected forest-products for supplementary and emergency income. The future of the rattan and timber trade on Leyte is seriously threatened by agricultural encroachment and intensive collecting pressures in the absence of forest management.

We studied species richness and density of rattan palms in 50 plots of 10 × 100 m2 each between 250 m and 2420 m in eight sites in Lore Lindu National Park (LLNP), Central Sulawesi. Rattans were observed in all sample sites, representing three genera and 34 species. The elevational patterns for species richness and density were humped-shaped with maxima around 1000 m. Polynomial models of second order explained 59 and 32% of species richness and density with the factor elevation, respectively. A majority of rattan species (65%) overlapped between 1000 and 1100 m elevation, while a pronounced change in the rattan flora occurred above 1100 m. Commercially important rattan species (Calamus zollingeri, C. ornatus var. celebicus, Daemonorops macroptera) were not observed above 1250 m. The change of species assemblage was significantly related to elevation (56%), followed by geographical distance (47%) and precipitation (40%). Less than 10% of LLNP is lowland forests, much of which is threatened by agricultural intensification. In contrast, montane forests are well represented in the park and high elevation forests are not subject to agricultural conversion or intensive harvesting of rattan and other forest products. peerReviewed

Data from fifteen phytosociological studies were merged and classified to describe and compare the vegetation of geo­graphically separated and climatically different Mopanev eld types in South Africa. Namibia and Zimbabw e. Seven v egetation types and ten major plant communities were identified using TW INSPAN. Vegetation types were separated according to geo­graphical regions. There were significant floristic affinities even though there w ere geological and climatic differences between the regions. Plant communities were described according to vegetation structure, habitat and floristic composition. Although environmental data were not adequate for a detailed ordination. DECORANA reflected the distribution of vegetation types and major plant communities along environmental gradients. Limitations of large phytosociological syntheses were also addressed. Species richness (alpha diversity) was calculated for each geographical region. The Musina (Messina) region north of the Soutpansberg. South Africa, has the highest species richness, and Kaokoland. Namibia, the lowest Due to irregular annual rainfall patterns in semi-arid Mopaneveld, it is suggested that variance in species richness is associated with temporal vegeta­tion states induced by rainfall events. Species richness of Mopaneveld was further compared w ith other sav anna types.

An analysis of the vegetation of the Sterkfontein Caves (i.e. the natural area surrounding the caves) is presented. Releves were compiled in 24 stratified random sample plots. A TWINSPAN classification, refined by Braun-Blanquet procedures, revealed six plant communities, also referred to as vegetation units. For each of these vegetation units the species richness was determined. Plant communities of conservation importance were identified and new associations were formally described.

The conservation of forest resources has been recognized as crucial to the sound and sustained development of tropical developing nations. Preservation of undisturbed tropical forest remnants, particularly in mountainous regions, through such means as national parks is justified on the basis that forest reserves: (1) provide invaluable watershed protection to growing lowland populations, agricultural crops, and industries; (2) contain extremely diverse, but as yet poorly understood, flora and fauna of potentially significant educational, pharmaceutical, and economic value; (3) offer subsistence resources critical to poor, landless farmers and minor forest product collectors; (4) represent a potential source of much needed foreign exchange earnings through the development of tourism; and (5) are rapidly disappearing. However, successful establishment and management of forest preserves will likely be difficult in most tropical developing countries as a consequence of the following: (1) growing land-use pressures, particularly the spontaneous and frequently illegal conversion of forests to farm lands by impoverished landless families; (2) national development goals and continued reliance upon raw materials, such as timber, minerals, and energy, and plantation-grown agricultural products (for example, coconut, sugar-cane, pineapple, coffee, rubber, and oil palm) for foreign exchange earnings; and (3) insufficient and conflicting support within government agencies. All of these factors impede current efforts to establish and manage the Leyte Mountains National Park in Leyte, Philippines, and are also present to varying degrees in attempts to conserve tropical rainforest remnants elsewhere.