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Action on the hill: Working towards the Cathedral Peak research catchments as a sentinel site for SAEON
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The Cathedral Peak weirs are being cleaned …
Admittedly, the uKhahlamba Drakensberg Park World Heritage Site is by no means a hill, with the escarpment reaching above 3000 metres in places, encapsulating arguably some of the most dramatic scenery in South Africa ...
It makes for a great office! And how can one say no to working in the only area in South Africa to have world heritage status designations for both natural and cultural value criteria?
As if these are not reasons enough for working there, the reality is that the Drakensberg is a critical catchment for a water scarce South Africa.Gauteng, for example, relies heavily on water from the KwaZulu-Natal uKhahlamba Drakensberg and Lesotho Highlands catchments, where water is transferred through the Tugela-Vaal transfer tunnel and the Lesotho Highlands Water Project to Gauteng.
Water demand in this province is on a steep increase and demand exceeding supply threatens to become a stumbling block for the economic growth of the country. Supply may be compromised by a number of factors including unsustainable demands, poor management of water resource infrastructure, poor land use/ management impacting negatively on hydrology and dam infrastructure, as well as poor planning or a change in weather patterns that fundamentally alters the hydrological functioning of critical catchments and their ability to deliver water.
Global change impacts
SAEON’s mandate is to understand global change impacts in a manner that provides meaningful data for policy makers for decisions around managing our natural capital assets sustainably in the face of a changing world. The impact of changes in weather patterns (amount of rainfall, severity of events, seasonality, variability, etc.) needs to be understood to inform future planning for water resource management.
SAEON has been involved in monitoring at the Cathedral Peak site for several months. The site used to be home to one of the outstanding achievements of South African science – the study of long-term water yield from grassland in response to fire management and afforestation. Due to the long-term weather and streamflow records that exist for Cathedral Peak, the site offers the perfect opportunity, with a long enough time series, to detect and monitor the impact of climate change on hydrological responses. A critical ecosystem service of the uKhahlamba Drakensberg is its ability to supply water dependably through low flow “dry” periods.
One of the questions relating to climate change is, therefore: How will changes in weather events impact on the ability of this system to sustain low flow water delivery?
Cleaning the weirs
Monitoring at the site was discontinued in the 1990s. As a result of cessation of maintenance of the infrastructure, the weirs have long since silted up with soil and a surprising amount of organic material. The first step in getting these weirs up and running again is a simple but expensive exercise of cleaning. The good news is that, with funding from the government’s Expanded Publics Works Programme and Working for Water, cleaning on the weirs started in earnest in January 2012.
To date four weirs have been cleaned, each representing relatively pristine catchments. We are hoping to revitalise an additional two weirs - a previously forested catchment and a fire exclusion catchment - to enable a comparison among these different treatments with the pristine grassland sites.
Mammoth task
This immense task has seen the movement of over 200 tons of soil, moved manually out of the weirs by a team of 19 people over a period of two and a half months. The project demonstrates how science can link to communities through providing job creation - for the poorest of the poor - to help maintain research infrastructure.
In addition to simply providing jobs, the training interaction in explaining why these activities are necessary and how they relate to the communities themselves is invaluable. I have enjoyed sitting under the only bush for miles, shielding ourselves from the hot sun during a tea break, responding to questions about the work we are planning, climate change and the environment in general.
These gentle interactions also provide an opportunity to promote science in education, explaining where science can take you in a career and encouraging those with children to promote the value of this subject at school with learners.
Advancing students in science
An additional and significant benefit to reinstating monitoring activities at the Cathedral Peak research catchments is that the site, research infrastructure and data emanating from it provides valuable education opportunities for university students across an array of disciplines, from hydrology to ecology. With its strong environmental gradients, the site is the perfect living laboratory to investigate global change impacts on ecosystems.
Promoting and providing opportunities for young scientists is a mantra of both Ezemvelo KZN Wildlife (EKZNW) and SAEON, so we were delighted to invite to the site the first team of hydrology Honours students from the University of KwaZulu-Natal’s School of Agriculture, Earth and Environmental Sciences in many years.
The journey up Mike’s Pass to get them to the catchments was an experience in itself and there were many relieved faces when we arrived at the first weir. Here students saw the reality of what it takes to maintain streamflow monitoring infrastructure and the result of not keeping up this maintenance.
The sound theoretical basis that this class of 10 had was brought to life through seeing and experiencing first-hand what catchments really looked like, and through lectures by the University of KwaZulu-Natal’s Michele Warburton and Mark Horan. For most of these students it was their first time at the UKhahlamba Drakensberg, so needless to say we made them climb hills to get a perfect view of the local catchments.
To give added meaning to this first-hand experience, the students were set to work surveying the morphometrics of one of the cleaned weirs. When the exercise was explained, there was a worried set of faces at the realisation that they had to get in there and get wet! Committed to instilling a sense of passion and fun around science, Michele, Mark and I all jumped in to lead by example. Admittedly I relished the exercise, with the braver students following suit. Fun was had by all.
Biodiversity responses
In addition to the hydrological function, SAEON is interested in looking at biodiversity responses to global change. The uKhahlamba Drakensberg provides significant environmental gradients to look at species shifts along these.
Questions being built into the long-term monitoring vision for the Cathedral Peak research catchments being developed by SAEON in collaboration with EKZNW include: How will vegetation respond along these gradients and are some species responding differently to others, switching a competitive balance? What is the link between vegetation change, plant traits, fire and response to climate change? What is the interaction between vegetation and the water balance and how might we expect this to change?
The Brotherton trial, located in the Cathedral Peak Monitoring Catchment area, was set up in 1980. Driven and maintained largely by Professor Terry and Dr Colin Everson of the former Department of Forestry’s Cathedral Peak Research Station, the trials were designed to investigate the effects of burning regimes (season and frequency) on vegetation.
Treatments have been largely maintained from this time. From 1980 to 1990 the plots were surveyed biennially; subsequently sampling has been somewhat intermittent.
A collective decision was taken to attempt to resurvey the vegetation of these plots over February and March 2012. Under the supervision of botanical expert Dr Rob Scott-Shaw, a collaborative team of EKZNW and SAEON interns and research technicians completed the vegetation assessment of all 34 active plots. This included 200 point samples and 40 tuft size and distance samples per plot.
Non-grass species were also surveyed by Dr Scott-Shaw and biomass surveys, using a disc pasture meter with calibration clippings, were done as a training exercise for all involved. The entire exercise acted as a skills transfer mechanism from the experienced to those still developing their skills.
While the vegetation survey provides information on the impacts of different burning regimes on species composition in the plots, SAEON is interested in analysing the data to determine if there are any directional responses despite treatment, as they may indicate a climate signature.
The resurvey has prompted further focus of the value of the Brotherton plots, building on efforts in 2004 to reinforce support for the continuation of these plots, not only as fire management experiments, but also for their value for global change research. In the face of budget constraints and staff shortages, strong motivations are needed to secure the resources necessary to maintain such long-term trials.
A formalised protocol is currently being developed for the long-term monitoring and maintenance of these plots, including well developed conceptual models where, collaboratively between SAEON and EKZNW, we are exploring ways of ensuring the sustained continuation of this valuable trial. Also contained within this document will be a list, by no means exhaustive, of identified research opportunities which may be of interest to universities.
The intention is to consolidate all the information and data on these plots to enable future research.
