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ECOLOGY AND CONSERVATION
[Climate Change] [Conservation Farming] [Cycad Conservation] [Protea Atlas Project] [Seed Research]
Scientific staff in the Ecology and Conservation Directorate, based at the Kirstenbosch Research Centre, were active with ongoing research projects that have firmly positioned the NBI as a key player in biodiversity science and conservation in Africa. Scientists continued to provide national leadership on policy research and advice in the area of plant diversity and sustainable use.
In 2001 funding was approved for a new two-year collaborative project between the NBI (South Africa) and the CNRS* (France) under the auspices of the Climate Change programme. The project Functional changes in vegetation of the Cape region (Floristic Kingdom) in response to global change is centred on the study of plant functional types along gradients between karoo and fynbos vegetation. NBI scientists participated in the first science planning meeting in Montpellier, France, in July to set the agenda for the first year's work on this project which will add to the understanding of plant form and function in two biodiversity hotspots.
Other climate change research projects currently under way include an examination of the effects of global climate change on savanna ecosystems, the effects of elevated atmospheric CO2 on grassland ecosystems and corridor design for biodiversity conservation in the face of climate change.
The results and potential implications of the climate change research under way at the NBI were also presented at a workshop on Climate change and forests in Tanzania, as well as at international workshops in France, Kenya, the United Kingdom and the United States. One of the scientists from the Climate Change Programme was invited as scientific advisor to a DEA&T presentation on Climate change impacts on South Africa, delivered to the South African government cabinet.
A colourful popular booklet sponsored by WWF-SA summarizing the results of earlier climate change research, The heat is on - impacts of climate change on plant diversity in South Africa, was released to the media in September and generated a number of newspaper, radio and television reports, including international wire news stories in the United Kingdom and United States.
CLIMATE CHANGE RESEARCH RESULTS
- Bioclimatic modelling has revealed the potential extinction risk facing indigenous species of the Fynbos and Succulent Karoo Biomes. In the Fynbos Biome, the Protea Atlas Database enabled the use of this group to estimate the extent of climate change impacts on natural plant species. Up to 30% of indigenous Proteaceae face extinction if they are unable to shift their geographic ranges completely to keep pace with climate change. Up to 60% of Proteaceae species could lose more than 90% of their current geographic range. Poorly dispersed species are particularly vulnerable. Rare species with small geographic ranges are generally more at risk of range dislocation (complete range shift or range extinction) than common species with broader ranges.
- Fieldwork on seed dispersal has found that occasional extraordinary wind events (probably whirlwinds) are able to provide significant seed dispersal events, suggesting that wind-dispersed species may be more able to climate change than ant- or rodent-dispersed species in the Western Cape. In the arid Succulent Karoo, a combined modelling and fieldwork study on Aloe dichotoma (kokerboom or quiver tree) has revealed a remarkable agreement between the modelled predictions of expected mortalities and population decline, and observed population decline. This suggests that the modelling techniques used are robust, and that the early signs of climate change may already be visible in our natural vegetation.
- Dynamic modelling has revealed the close dependence of tree/grass balance in savanna systems to atmospheric CO2 levels. Rising CO2 strongly promotes the success of trees growing competitively with grasses, and this effect is mediated by fire frequency. This work shows that previous interpretations of grassland expansions in southern Africa during glacial conditions that have been understood as signs of aridity should be re-evaluated. It seems that rising CO2 has been under-appreciated as a factor behind the national problem of bush encroachment. This phenomenon could therefore be important in calculating the cost of atmospheric CO2 increase to this country and in assessing the ability of natural savanna and woodland ecosystems to sequester carbon.
- Results of the project on elevated atmospheric CO2 on productivity and water use of South African C4-dominated grassland ecosystems have indicated the potential for improved ecosystem productivity and water use efficiency under elevated CO2 and present rainfall scenarios. Ecosystem productivity may be limited by the availability of other resources such as nutrients. A shift in community structure is also possible and is most likely influenced by availability of other ecosystem resources apart from CO2.
- An understanding of physiological and structural adaptations in diverse growth forms to environmental stress conditions is important for predicting the possible impacts of climate change on these growth forms. Structural analysis of the ericoid leaf form, a dominant structural type in fynbos vegetation (and an important component of biodiversity), has revealed that this form is not sclerophyllous, and therefore that its structure and presumed function requires a full reappraisal. Stomatal function appears not to be determined by water-saving considerations, but rather that stomata are held in grooves on the abaxial surface of the inrolled leaf in order to maintain stomatal opening under atmospherically dry conditions. This strategy is likely to maximize carbon uptake during common windy and dry conditions.
- A new project focuses mainly on the ecophysiological responses of the economically significant indigenous savanna plants to climate change scenarios projected over geological time scales. The preliminary findings suggest that three tree species, namely Acacia karroo, A. nilotica and Dichrostachys cinerea, respond differently to CO2 treatment. It appears that A. karroo and A. nilotica might flourish under conditions of higher CO2 compared to D. cinerea, since the former two species appear to have invested much carbon in above-ground plant material as opposed to the latter. However, the question of below-ground carbon investment is very important and needs still to be investigated.
The Conservation Farming Project received very positive feedback from the project funders, the Global Environment Facility, who visited the project during the year as part of their global evaluation of medium-sized projects.
To date, workshops have been held in all four study sites included in the Conservation Farming Project. The workshops involve researchers, farmers, and labourers from a range of farms in each district. A key factor emerging from all the workshops is that farmers lack information and support services.
Twenty-one contract staff and consultants have been appointed to assist with the Conservation Farming Project. Most of these appointments are researchers and this has provided a boost for ecological research in South Africa. Ten student projects are currently being supported as part of the project, including five Ph.D. projects.
The Conservation Farming Project website (http://www.nbi.ac.za/consfarm/cfindex.htm) was substantially updated to enable stakeholders to download relevant information. The website now contains fact sheets, a reference database and information on sites.
As part of an ongoing sponsorship agreement, Mazda Wildlife Fund supplied the Conservation Farming project with a new vehicle.
CONSERVATION FARMING RESEARCH RESULTS
- A project on the importance of porcupines as ecosystem engineers in the Nieuwoudtville area is nearly complete. The data showed that porcupines turn over large volumes of soil and selectively remove certain bulb species. Preliminary analysis suggests that this activity maintains bulb diversity, increases rainfall infiltration (up to 10 times faster in areas with porcupine diggings than in areas without porcupines), and influences the storage of soil carbon (areas with high bulb numbers associated with porcupine activity contained much higher levels of soil carbon).
- Studies of seed dispersal of Brunsvigia bosmaniae were used to provide detailed data on the effects of land use on dispersal and establishment of different groups of plants. The results showed that dispersal was interrupted by farm structures such as fences and also occurred only in specific 'corridors'. This means that once plants are eliminated from a landscape, they cannot always re-establish from seeds. Moreover, establishment depended on a combination of soil type and rainfall. Under low rainfall, plants established only on dolerite soils, but they would establish on other soils under higher rainfall.
- Data on soil carbon together with above- and below-ground biomass have now been collected at three of the four study sites. This means that the amount of carbon stored in the soil and in plant biomass per hectare can be calculated, giving an idea of how carbon sequestration changes with land use.
- Experiments on the effects of fire, as a land management option, on the presence and flowering of geophytes in the Nieuwoudtville area were also undertaken. The study compared unburnt plots with plots that were burnt or brush-cut. Findings showed that flowering increased in burnt and cut plots but that there were no species that flowered only after fire. Frequently burnt plots were found to have substantially fewer species.
The NBI has been instrumental in completing a status survey and action plan for the world's cycads, which was submitted to the IUCN for final publication in 2002. The Cycad Action Plan clearly identifies priority species and areas for conservation and therefore makes it easier to access funds for specific projects.
The IUCN Cycad Specialist Group has been reconstituted for the next three-year term specifically to carry out the actions outlined in the Cycad Action Plan. The members represent eight countries (Australia, China, Kenya, Mexico, South Africa, Thailand, USA and Vietnam). The key areas that the group will focus on are Red Lists, collections in botanic gardens, habitat conservation, trade, liaison with cycad enthusiasts, taxonomic information, sustainable utilization and community nurseries in developing countries, and fund-raising.
- The fieldwork for a National Geographic Society-funded project on cycad pollination was completed in December 2001 and generated several significant results. Thrips have been discounted as effective pollinators in many plant groups because of small pollen loads. Cones visited only by thrips had the same number of pollen grains per ovule as beetle-pollinated cones. Cycads pollinated by thrips were furthermore found to have diurnal heating patterns and volatile attractants that were different from those of cycads pollinated by weevils.
- Research into how cycads with different life histories respond to harvesting is being used to develop government policy on cycad trade. An analysis of 10 years population data for two cycads showed that seed harvesting had a negligible effect on cycad populations, even when adult life spans varied from 50 years to > 300 years.
PROTEA ATLAS PROJECT
The Protea Atlas Project entered a new phase with the start of an externally funded collaborative project aimed at statistical analysis of the data collected by the Protea Atlas Project over the past 10 years. To this end, the project leader and co-workers attended workshops on Bayesian statistics and modelling in Santa Barbara, USA. Bayesian modelling is being employed to predict the distribution and biodiversity of proteas on environmental and spatial variables.
Data gathered by the Protea Atlas Project is being put to use by the Cape Action Plan for People and the Environment in planning conservation areas, by the NBI's Climatic Research group for mapping Global Climate Change and also to help map the vegetation types within the Fynbos Biome.
A new and very unusual species of Leucadendron was discovered by the Protea Atlas Project, the eighth new species to be discovered since the Project's inception.
There are a large number of rare and threatened plant species in different parts of the world and seed conservation research aims at establishing and perfecting the techniques required for long-term storage of seed as a means of conserving their genetic potential. To this end, an NBI scientist attended the Kew International Workshop on Seed Conservation: Turning Science into Practice held in the United Kingdom in July 2001 where opportunities for possible research collaboration between the Kew Millennium Seed Bank and the NBI were discussed.
MARY GUNN LIBRARY
The Mary Gunn Library, housed at the National Herbarium, continued to provide a valuable service to the scientific staff of South African research institutions, as well as support to institutions in the SABONET network.
The Library enjoyed a busy year, with almost 2 000 books and photocopies of articles issued and over 5 400 telephonic and e-mail enquiries fielded. Over 2 650 copies of the contents pages of new journals were circulated to internal users and SABONET participants and 800 books and photocopies of articles were requested through national and international interlibrary loans.
A presentation on the management and administration of a library was given to participants in the SABONET Botanical Gardens Management Course. The Mary Gunn Library was marketed through an article in SABONET News as well as through the NBI website.
HARRY MOLTENO LIBRARY
The Harry Molteno Library, housed in the Kirstenbosch Research Centre, experienced a successful year, with an increase in all the main areas of activity. Over 1 300 enquiries were processed and almost 1 100 books issued. The Library hosted a meeting of members of the Special Libraries Interest Group at which the librarian spoke on Developing and managing a corporate website. The Wednesday Club visited the Library to view its rare book collection.
The increasing cost of journal subscriptions led to several titles being cancelled at the end of 2001. This was before the drastic devaluation of the SA rand at the end of 2001, which has very serious implications for the library holdings unless additional funding can be sourced, as most of the acquisitions are published outside South Africa.
Training sessions on how to search the SABINET on-line databases were offered free of charge by SABINET to NBI research staff.
The websites designed and maintained by the librarian of the Harry Molteno Library enjoyed phenomenal growth during the year. Hits to the www.nbi.ac.za site have almost doubled, while the use of www.plantzafrica.com site has increased more than threefold. In March 2002, both sites passed the threshold of an average of 5 000 hits per day.
Several additions were made to the www.nbi.ac.za site during this period, including an expanded section on the Lowveld NBG, pages on the Conservation Farming Project, Leslie Hill Laboratory and the NBI-Ball Agreement. The site was constantly updated to promote events in the Gardens, with pages developed for concert programmes, art and sculpture exhibitions and plant fairs.
The www.plantzafrica.com site grew regularly as two Plants of the Week contributed by staff at Kirstenbosch and the Witwatersrand NBG respectively were added every week. Other additions to the site were information on listed invasive plant species, descriptions of the trees of the year, and many articles taken from past issues of Veld & Flora. The number of hits on this site is growing steadily as people discover its value as a source of information on indigenous plants.