Mires on Fire: Vasi Wetlands

From 2015 to 2017 members of the IMCG, including geographers, geologists and hydrologists, conducted a number of research visits to the Vasi peatland complex, at the eastern coast of South Africa, close to Eswatini and Mozambique

The goal was two-fold: to obtain a better understanding of the hydrological system of the peatland complex; and, to find out why some parts of the complex (Vasi Pan) suffered a great deal more from recurrent peat fires than other parts (Vasi North), even if both are under the influence of Pine and Blue gum plantations.

Based on the outcome of their research, the team aimed to formulate an advice to stakeholders (including local communities) on how to stop the fires, restore the hydrological system and to restart vegetation growth in the peatlands again. 

South Africa, and in particular Maputaland in the northern KwaZulu-Natal Province, holds a number of peatlands that are severely damaged by recurring peat fires. The Vasi peatland complex is one of them. Our South African colleagues had already warned us that our study area had suffered from particularly heavy fires in 2017. Having completed the first phase of our research project in 2015, where we uncovered the flow origins (discharge and recharge areas) and flow directions within the Vasi peatland complex area ( Elshehawi, 2019 ), we now arranged preparations for the next phase; how can we restore peat accumulation in the burned areas?

The goals for the present field excursion are three-fold: 1) revisit our study area and repair any equipment that has been burned, 2) to take additional water samples for dating the ground water (using C14-isotopes), and 3) to think of an integral course of action to restore the wetlands which can prevent future peat fires.

The Vasi Peatland Complex is an area of 230 ha, consisting of two discrete peatlands. Significant lowering of the water table has desiccated the peat in Vasi Pan. During a regional peatland survey in 1995 desiccation cracks were noted on the surface of Vasi Pan and reported to KwaZulu-Natal conservation officials.

However, in May 1996 local forestry officials of the Manzengwenya Plantation burned a fire break over the northern section of Vasi Pan in a routine veld management programme which resulted in the first peat fire of the dried surface layer (top 50cm). Continued plantation expansion has led to recurring peat fires for the past 20 years, leaving monstrous black patches deprived from any form of life (A) and (B).

Understanding these two peatlands will greatly increase the knowledge regarding the response of peatlands in stressed conditions. It presents an extreme example of what can happen if dehydration remains unchecked.

In order to understand the different outcomes for Vasi Pan and Vasi North, we first need to explain the Vasi peatland complex at landscape scale.

All peatlands in the area originally started out as streams. The oldest deposits - at Vasi North - started te develop ca. 8500 years ago, while peat formation in Vasi Pan started some 4000 years ago. This is why the peatlayer in North is thicker. Terrestrialization of both mires started about 3000 years ago. Some charcoal was found in the peat layers, but apart from that the peat has accumulated rather continuously and no large gaps in peat accumulation (due to burning) could be assessed.

The reason why Vasi North was longer resistant to earlier fires compared to Vasi Pan, seems to be that Vasi North is situated deeper in the hydrological gradient than the Vasi Pan peatlands. It is therefore wetter and received additional groundwater from the Vasi Pan peatlands upslope.

As we have visited here in 1996, 1998, 2004, 2015 and now 2017, we expect to be able to draw a pretty clear picture of how the vegetation and erosion have responded to peat fires and ongoing desiccation.

On the 15th of October 2017 we organised our equipment, travelled to South Africa and started our fieldwork. We went in to have a closer look and try to analyse the mosaic that we are seeing before our eyes.

We proceeded to install the new equipment for measuring water levels and for analysing the ground water composition and age (C-14 isotopes).

An important find was that we uncovered a still intact Rhizome of a tussock. This is a major peat forming species and has preserved well.

Walking back to the car we try to comprehend what we saw today and tried to compare this with what we have seen in earlier years. Pictures taken from earlier visist enabled us to make a vivid comparison, and the results are shocking. In just ample years, sometimes only a few as two, the change in lanscape is stunning.

Having seen the current state of both peat systems, we are beginning to formulate our advice. Are we going to try to restore the peat forming vegetation? And if so, how many of the degraded top layer should be removed? Doing nothing will not restore any vegetation growth because the plants have been killed by accumulation of salts in the root zones of the plants.

The responsible government organisation tells us they are not happy about removing peat layers, because digging peat has been made illegal in South Africa now. We propose to hold off any intervention until the hydrological system is restored and replanting with pines and blue gums has stopped in the surrounding areas. These are in our opinion prerequisites before we can make a proper plan to restore vegetation growth in the degraded peatlands.

In order to come up with a plan for a future course of action, it is common practise to develop three scenario's: the current situation ('do nothing'), the original situation ('original'), and one for how the system could react after renaturalisation restoration  and removal of plantations ('renaturalisation'). These scenario's can be helpful in the decision-making process for stopping the fires.

The government has handed over the plantation to the local community in a community trust in order to manage the plantation and the related environment. The community is aware of the damage to the wetlands and the danger the fires pose to livestock. Most of the elders were probably born when Vasi contained shallow lakes and crocodiles (Kwenya and Manzenkwenya refers to crocodile), and they would have noticed the loss of cows that burned in the 2006 peat fire. However, these impoverished communities rely on afforestation to provide short and long term financial benefits, which are more substantial than any other financial activity in Maputaland. Hence they state:

“We know there is a problem, but we cannot remove the trees without alternatives being in place. Please work with us to find alternatives (in Sue J. van Rensburg, 2017).”

Perhaps the only ones fighting this reality are the officials tasked to provide alternatives to plantations or those who are responsible for managing these natural resources, but are unable to do so due to lack of coordination and lack of resolve to tackle the fire problems.

The fact is that these peatlands can be saved and should be saved, as was proven in the 1998 action taken by the then Department of Water Affairs and Forestry, who tasked themselves to manage the trees, control their planting, save water and save these mires. This should be done hand in hand with the community and alterative income streams should be generated parallel to the wetland restoration process.

Based on the available research, baseline conditions in terms of peatland hydrology restoration objectives should be formulated and a detailed restoration plan should be drafted: should we just rewet the peatlands by reducing the loss of water by evaporation, or should we additionally remove the degraded top soil of the peatland. And if the latter, how deep should that be done? Much of this knowledge is available already with the IMCG/ERA/WETREST/ALLWET research support. There is no need to wait for standard unilateral buffer guidelines for wetland protection.

What is needed is a precise delineation of wetlands in the area and precise determination of recharge zones that provide the wetlands with groundwater. In those recharge areas specific parts of the plantations bluegum and pine trees should be cleared and replaced by less groundwater requiring species (eg. Moringa). Or, alternatively, open up the buffer zones and wetlands for specific organic free stock grazing.

After that has been done we can advise to remove the dried and burned peat surface from the most affected mires. Removal must be too below the mineralised (salinized) and dried zone. The underlying wet peat layer needs to be replanted with indigenous (local) wetland species.

In areas with shallow peat layers or with no peat at all alternative income streams can be developed related to the restoration goals and activities, such as planting less water consuming fruit trees or medicinal plants. Other possibilities are introducing organic stock farming, tourist activities, such as rangeland tourism and hiking.

This story about the burned Vasi peatland complex has shown that when a peatland has been compromised in its foundational watersystem, it is just a matter a time before the peat catches fire.

The peat layers have been conserved for thousands of years due to the high groundwater tables. There have been dry periods before, reflected in differences in increased decomposition grades of the peat, but no peat has been lost due to intensive burning during the last 7000 tears. So the very dry years are not generally causing peat fires, but regular peat fires can occur when the groundwater buffer is depleted by other causes, such as drainage of increased evaporation by forest plantations.

A reduction of water losses by forest plantations, by replanting with indigenous trees can be a first step into a collaborative and integral approach of land use. But is will not be enough. More sustainable socio-economic development of the area is urgently needed to provide alternative income for villages. But in the end, any functioning and sustainable socio-economic activity, ultimately depends on a resilient natural system.

This IMCG-supported research project links in with the IMCG's goals to facilitate local research and provide relevant study locations, equipment, financial support, knowledge and educate, park managers, as well as master and PhD students.