Jonkershoek stream monitoring
The Jonkershoek experimental catchment project was established in the mid 1930s to investigate the impacts of exotic tree plantations on water delivery by catchments. The Eersterivier has its source in a number of small catchments in the Jonkershoek valley. Six of these small catchments have been continuously monitored with water level data recorded hourly at V-notch weirs. Weather monitoring complements streamflow monitoring at Jonkershoek to help us understand the interaction between climate, vegetation and runoff. SAEON has been supporting this monitoring since 2007 and took over full responsibility in 2010. Since then old monitoring equipment has been replaced with electronic instruments that can relay data to our offices.
High elevation weather monitoring
A paucity in high elevation rainfall data has been identified as a constraint to accurate hydrological modelling in the Western Cape. In response to this we have installed a high elevation weather station in the Jonkershoek mountains which will also improve our understanding of the dynamics influencing streamflow. Other high elevation sites for weather monitoring are in the pipeline. To view current weather click here.
Modeling future vegetation distribution
The distribution of South African biomes is expected to be drastically altered by climatic change and increasing atmospheric CO2 in the 21st century. Developing the capacity to anticipate these changes is of critical importance if we are to mitigate and efficiently adapt to the reorganization of South African vegetation cover. Most previous work attempting to project global change impacts on vegetation in the greater Cape Floristic Region has involved approaches that correlate present climate with plant or biome distributions, then extrapolate these correlations to estimate distributions under projected future climatic conditions. Dynamic Vegetation Models (DVMs) simulate the impact of climate and CO2 change on plants using physiological principles and explicitly model vegetation dynamics and disturbance, rather than using simple climate correlations. DVMs were originally conceived of as a tool for simulating global change impacts on vegetation patterns at the global or continental scale, ignoring range-restricted vegetation types. Therefore plant types and processes important in determining the distribution and functioning of our most biodiverse and threatened biomes, particularly Fynbos and Succulent Karoo, are absent or poorly represented. The SAEON Fynbos node is modifying an existing DVM - originally intended for tropical biomes and parameterized specifically for Africa - to include the plant types and ecological processes relevant in these neglected South African biomes. We hope to provide better simulations of climate change impacts across South Africa’s biomes, and understand the feedbacks between vegetation, hydrology, climate and human livelihoods.
Impact of atmospheric Nitrogen deposition
In collaboration with the University of Arizona and University of Cape Town, we have been investigating the inputs of nitrogen in and around the city of Cape Town from atmospheric sources. Fynbos is characterised by the extremely low nutrient soils on which it grows and the negative impacts that fertilisers have on typical Fynbos plants. This study will help us quantify the threat of anthropogenic N on Fynbos growing near the City.
Cloud precipitation has long interested Fynbos botanists since Rudolf Marloth first attempted to quantify moisture provided by clouds on Table Mountain at the beginning of the 20th century. We are investigating the impact of this form of precipitation by setting up paired rain gauges along altitudinal gradients. One rain gauge will be modified to capture cloud precipitation whilst the other measures rain. We also monitor the impact of cloud precipitation on soil moisture.
Repeat surveys to detect vegetation change
This project involves repeat vegetation surveys performed in the Cape Point section of Table Mountain National Park in 2010, providing a 44 year record of vegetation change, and in the Baviaanskloof Mega-Reserve in 2012, a 20 year record. We are using these data to test for directional changes in diversity and trait composition and to test hypotheses relating these changes to fire history and climate change. These studies are being performed in partnership with researchers from the University of Connecticut, University of California, Davis, and the Australian National University and links to our project exploring plant trait variation across climate gradients. See more details of the collaborative project at http://darwin.eeb.uconn.edu/wiki/index.php/Parallel_Evolutionary_radiations_in_Protea_and_Pelargonium_in_the_Greater_Cape_Floristic_Region or contact jasper_at_saeon.ac.za
Topography and microclimate variation on Table Mountain
Topographic heterogeneity confers spatial resilience, or buffering capacity, in the face of climate change by generating a wide range of environmental conditions on local landscapes and reducing the distances organisms need to move to offset rapidly changing conditions. We are collaborating with Prof David Ackerly at the University of California, Berkeley, on a project exploring the effect of topography on microclimate on Table Mountain. We have placed a network of temperature and humidity loggers on the mountain with the hopes of measuring the range of microclimatic variation and allowing us to develop models to predict microclimate based on elevation, slope, aspect and the distance to the ocean. We will use these models to see if microclimate can predict the fine-scale occurrence of a set of focal species. Contact: jasper_at_saeon.ac.za
What happens to soil moisture dynamics when a grassy disturbed vegetation type is restored to shrub dominated renosterveld? This is a question SAEON is hoping to answer in collaboration with Dr Pippin Anderson (University of Cape Town) and her students at their long-term restoration trial in SANPark’s Rhodes Memorial Game Camp. SAEON has installed soil moisture monitoring equipment in the soil under plots which have been subjected to different restoration techniques.
Plant trait variation across climate gradients
We are exploring how fynbos plant traits vary across climatic gradients in partnership with researchers from the University of Connecticut, University of California, Davis, and the Australian National University. We have measured detailed trait data for ~1200 plant species collected on the Cape Peninsula and in the Baviaanskloof, Langeberg, Kogelberg and Cederberg mountain catchments. We have focused our collecting efforts on species that occur in plot lists from existing vegetation surveys so that we can examine trait variation within and between communities across a spatial climatic gradient. The hope is that understanding variation in traits across spatial climate gradients will improve our ability to predict how traits within a site should change through time as climate changes. This project is linked to our repeat vegetation survey projects. See more details of the collaborative project at http://darwin.eeb.uconn.edu/wiki/index.php/Parallel_Evolutionary_radiations_in_Protea_and_Pelargonium_in_the_Greater_Cape_Floristic_Region or contact jasper_at_saeon.ac.za
The Baviaanskloof catchment area is located at the eastern-most extent of the fynbos region where the rainfall pattern has less seasonal variation than the winter rainfall region to the west. In partnership with LivingLands, we monitor rainfall, floodplain groundwater levels, and streamflow in the catchment to better understand the catchment response to climate and land cover changes. Monitoring has been ongoing since 2011 and the data is being used to calibrate hydrologic models through which scenarios of restoration, land and water management, and climate change will be explored.