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08 September 2020 | Story Leonie Bolleurs | Photo Falko Buschke
Dr Falko Buschke says the iconic sandstone cliffs of the eastern Free State are key to protecting wild plants and animals from climate change.

The iconic sandstone cliffs of the eastern Free State are often the focus of paintings and postcards. Now, new research shows they also protect wild plants and animals from climate change. This finding is the outcome of a collaborative research effort by the University of the Free State (UFS); BirdLife South Africa; the Vrije Universiteit Brussel and KU Leuven, Belgium, which has recently been published in the journal Biological Conservation.

Mountains key for climate change mitigation

The study, led by Dr Falko Buschke from the Centre for Environmental Management UFS, used satellite data from NASA to track the ecological effects of wet and dry seasons, including the record drought of 2015/16. This showed how vegetation on the cool and moist mountain slopes was less affected by dry spells.

The complex physical terrain allows moisture to accumulate in the shaded parts of the south-facing slopes and ravines. This creates cool and moist habitats for plants and animals that wouldn’t survive in the rest of the hotter and drier landscape.

The team also discovered that these positive effects of mountains do not end at the foot of the mountain, but extend at least 500m into the flatter lowlands. “Presumably because water and nutrients accumulate in these surrounding buffers due to run-off,” says Dr Buschke.

Butterflies find safety on mountains

In addition to their high-tech analysis of the area, the team also relied on old-fashioned fieldwork to monitor butterflies over two years. “The data showed us how these insects find safety on mountains during harsh climate conditions and can then recolonise the rest of the landscape after conditions improve,” explains Dr Buschke. “This gives us clues on the best way to protect nature,” he adds. 

This study took place in the Rooiberge-Riemland Key Biodiversity Area (KBA), an area significant for maintaining global biodiversity. Several species of insects, reptiles, birds and mammals here occur nowhere else on earth. “If they disappear here, they will go extinct from the whole planet forever,” says Dr Falko Buschke. 

Despite its ecological significance, most of the area is covered by commercial farmland. So, the next stage of the project is exploring ways of protecting these important habitats while ensuring that farmers can continue producing food and supporting rural livelihoods. 

Farmers hold the key to preserving biodiversity,” says Dr Buschke, “so conservation scientists need to work closely with them to ensure that we protect species for future generations.” 

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Well-established root system important for sustainable production in semi-arid grasslands
2015-02-24

Plot layout where production and root studies were done
Photo: Supplied

The importance of a well-established root system for sustainable production in the semi-arid grasslands cannot be over-emphasised.

A study of Prof Hennie Snyman from the Department of Animal and Wildlife and Grassland Sciences at the University of the Free State is of the few studies in which soil-water instead of rainfall has been used to estimate above- and below-ground production of semi-arid grasslands. “In the past, plant ecological studies have concentrated largely on above-ground parts of the grassland ecosystem with less emphasis on root growth. This study is, therefore, one of the few done on root dynamics in drier areas,” said Prof Snyman.

The longevity of grass seeds in the soil seed bank is another aspect that is being investigated at present. This information could provide guidelines in grassland restoration.

“Understanding changes in the hydrological characteristics of grassland ecosystems with degradation is essential when making grassland management decisions in arid and semi-arid areas to ensure sustainable animal production. The impact of grassland degradation on productivity, root production, root/shoot ratios, and water-use efficiency has been quantified for the semi-arid grasslands over the last 35 years. Because of the great impact of sustainable management guidelines on land users, this study will be continuing for many years,” said Prof Snyman.

Water-use efficiency (WUE) is defined as the quantity of above- and/or below-ground plant produced over a given period of time per unit of water evapotranspired. Sampling is done from grassland artificially maintained in three different grassland conditions: good, moderate, and poor.

As much as 86, 89 and 94% of the roots for grasslands in good, moderate and poor conditions respectively occur at a depth of less than 300 mm. Root mass is strongly seasonal with the most active growth taking place during March and April. Root mass appears to be greater than above-ground production for these semi-arid areas, with an increase in roots in relation to above-ground production with grassland degradation. The mean monthly root/shoot ratios for grasslands in good, moderate, and poor conditions are 1.16, 1.11, and 1.37 respectively. Grassland degradation lowered above- and below-ground plant production significantly as well as water-use efficiency. The mean WUE (root production included) was 4.79, 3.54 and 2.47 kg ha -1 mm -1 for grasslands in good, moderate, and poor conditions respectively.

These water-use efficiency observations are among the few that also include root production in their calculations.

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