Article created by Georgina van Biljon 28-02-2025
Photo above: a rehabilitation nursery near Wolseley with a variety of indigenous plants grown for a LandCare river rehabilitation project (2011)
Here are some tools to make a plant list for rehabilitation
1. Discover your local vegetation type that occurs at the site’s location.
This needs to be the basis of your plant list. Use https://www.sanbi.org/biodiversity/foundations/national-vegetation-map/ to identify your vegetation type and it also provides a plant species list.
Or use Cape Farm Mapper https://gis.elsenburg.com/apps/cfm/ and this video (video link to be added) to help you download or create a plant list.
Get to know these plants, what habitats they grow in and other interesting information. A good place to start is PlantZAfrica website: https://pza.sanbi.org/ which is developed by SANBI and is reliable information on indigenous plants of South Africa.
2. Consider your ecosystem that you are re-habilitating.
Is it a riverbank, a wetland, a forest, an estuary, a mountain slope? Often there are plants that are specifically found in these habitats or ecosystems. Within these systems there might be specific niches (micro habitats) that a plant grows in. Try to understand those habitats and niches at your location. Planting a plant outside it’s natural habitat may increase plant mortality.
3. What is the cause of the problem (degradation driver)?
If the cause of the problem is overgrazing which is resulting in dongas, then one needs to have a problem-solving approach at this initial stage. This can influence the plant list. For example, if all the palatable grasses are removed from the system due to overgrazing, then you need to focus on replacing those plants. But first try to address the cause of the degradation, otherwise it will be a waste.
4. Balance pioneers with climax species
Pioneers are the fast-establishing plants and are often seen as ‘weeds’. These plants have an important role in restoration in creating a shelter for other slower growing plants (climax species). Pioneer species die after a few years and establish in disturbed habitats or soils. It is important to get a balance between the pioneers and climax species in your plant list. Pioneers are usually sown in by seed, while climax plants are grown in nurseries, so that they have some time to establish before they are planted out. Successional processes in nature allow for natural recovery. One needs to mimic (copy) these processes so that your efforts and resources are decreased. This is later discussed in ‘budget limitations’ below.
Image above: Cape Cairos site: A combination planting of pioneer and climax species. Oesteospermum moniliferum (pioneer shrub), Leonotus leonurus (pioneer shrub), Dodonea viscosa var. angustifolia, Kiggelaria africana (climax tree) (photo taken 2021-11-19)
5. Ecosystem engineers or keystone species
Some plant species shape or influence the ecosystem more than others due to the role they play, for example Palmiet (Prionium serratum) has a massive influence in slowing down the water’s velocity and has many beneficial aspects to the ecosystem (creates a habitat for other species) and provides amazing ecosystem services like water filtration. (See our article on Palmiet)
One can focus or prioritise on establishing this plant in a freshwater system before other plants. There are many other keystone species in other habitats. One needs to do some research to discover these goldmines. Once these plants are established, it may help with other plants being established (similar to the role of pioneers).
What is your future state that you want to rehabilitate to? In other words, what is your goal or target that you are trying to reach. We will be expanding on this in separate article on: Rehabilitate to what?
If you are aiming at restoration to a near natural ecosystem, then you need to have high species diversity in your plant list. Revegetation is different to rehabilitation, which is different to restoration. Try to understand these concepts/ definitions through the Restoration Continuum developed by the SER (Society for Ecological Restoration): https://www.ser.org/page/Standards-Tools
Photo above: Intaba has been involved since 2013 in restoring this river zone near Tulbagh. It will never be completely restored, but we keep monitoring and try to improve biodiversity over time. Many of the ecosystem functions are working, water quality is improving, bird life has increased and the ecosystem buffers the effects of flooding.
Consider some practical aspects:
a) Planting methods:
If you decide to add some compost, biochar or mulch to the soil to assist with soil health and water retention, this may boost plant survival. This may enable you to plant a greater variety of plants, as some plants can handle more harsh conditions with few nutrients – such as Salvia sp. (see below), while others may need more care.
Photo above: Salvia africana- caerulea (https://pza.sanbi.org/salvia-africana) planted on a rehabilitation site near Tulbagh and did not receive any watering or soil additives. It is a hardy pioneer shrub that also has high natural recruitment from seeds.
Photo above: Plants planted with activated biochar in 'ponds' at Cape Cairos site (2020). These plants recorded a higher plant survival than those planted with out biochar.
b) Irrigation
Is irrigation available?
No – then one needs to consider what plants are more drought tolerant or by using strategic planting methods – inclusion of biochar or mulch to assist with soil water retention.
Yes - then one needs to choose a type of irrigation: a) dripper or b) overhead or c) manual.
The type of irrigation you choose will also affect your plant selection. Certain plants thrive in overhead irrigation (grasses and weeds) and type of irrigation is determined on site factors and soil types. See diagram below for distribution of water in different soil types.
Although dripper irrigation has amazing water saving abilities, is not fool proof.
Here are some aspects to consider: i) soil type, ii) securing of dipper lines, so they do not shift and iii) maintenance (we will expand on this to general maintenance in section c below).
i) Sandy soils are riskier with dripper irrigation, as plant mortality can increase if the drippers are not placed right next to the water-dependent plants.
ii) In the picture below the dripper line shifted and the plant did not receive sufficient water and died. Some plants are more water dependent than others and if you are using more climax tree species, one should check on shifting of dripper lines and soil moisture distribution (especially if the plants are on a slope).
Photos above: Podocapus elongatus young trees planted on rehabilitation sites died due to irrigation failure. Top photo: The finger is showing where the water drips out of the pipe, which is too far away from the tree and did not receive sufficient water. This is either caused by incorrect initial placement of plants or shifting of dripper pipes. Bottom photo: the tree was planted on a steep slope and did not receive water and died, as the dripper point was down slope from the tree.
c) General maintenance
How you design your maintenance plan can influence your plant list and should be considered at the initial planning phase of a project. Maintenance actions can include (but are not limited to): weeding, watering, pest/damage control & checking plant health.
Irrigation maintenance
Regular irrigation maintenance is crucial for plant survival over dry periods. If you want high plant survival then one needs to pay careful attention to this at least every time the irrigation is on, someone needs to walk through the irrigation checking that plants are receiving water. If they are not, then that needs to be fixed as soon as possible.
Photo above: Intaba team members undertaking irrigation maintenance at a rehabilitation site on the upper Breede River near Wolseley.
Weeds
Weeds can have an adverse effect on plant establishment, as they can choke plants, block out sunlight and use up resources.
If you want your plants to outcompete the fast-growing weeds or invasive plants, one can consider manual weeding (which is costly and time consuming), use of herbicides or one can look at other strategies.
These strategies we have developed over the years through trial and error, observations in field or just by chance. These strategies are not fully trustworthy, so please take them with ‘a pinch of salt’ and test them out for yourself. If you sow or plant a wide diversity of plants, you may see many of these aspects developing naturally in nature.
For example, broadcast sowing of indigenous seeds post burning may suppress establishment of invasive trees from seeds (Homes et al. 2008). We have had success with this on numerous sites, where invasive trees (Acacia sp.) have dominated and there is a large alien seed bank. Planting a sterile rye grass can be a cheaper alternative if you don't have access to indigenous seeds at the time, but one needs to make sure that it is sterile and does not become a weed.
Photo above: a rehabilitation site near Tulbagh where we sowed indigenous grasses to suppress agricultural weeds.
If you have a problem with an invasive grass (for example, kikuyu) on your site chocking planted plants, one can either use herbicides or fast growing indigenous pioneer bushes that will out-shade the grass and create some space for the climax species to grow underneath. We find best results using herbicide on kikuyu grass and then once the kikuyu has died, then we burn it and sow it with an indigenous plant mix and plant afterwards.
Weeds give us messages and we need to take note. Some weeds dominate in disturbed soils, some in saline or low nutrient soils. Check the soil chemistry where a certain weed is dominating, and you will learn much.
Photo above: Palmietvlei site, where Kikuyu grass (Cenchrus clandestinus) is dominating (Photo 2020-02-17).
Herbivory or pest damage
If one has a lot of rodents or other animals eating the young plants, then one needs to consider boosting predators, installing physical barriers or adapting your plant list.
Barriers: placing the edible plants under a spikey bush or have protection sleeves. Otherwise one may avoid including palatable plants, until rodent populations are controlled naturally by supporting their predators (for example, providing owl boxes and erecting poles for perching).
Photo above: a plant (Searsia angustifolia) that has been eaten by livestock on a rehabilitation site.
Plant health
Some plants may not thrive on site due to climatic influences or soil chemistry/health. Planting with compost and/or activated biochar does help with plant health.
If one plants or sows a variety of plants on a site, this may assist in overcoming plant sensitivities. If one plant is more sensitive to site conditions and dies, then there is another one that may continue in it’s place. Soil chemistry and soil health tests can help with assessing deficiencies and one can work towards correcting those imbalances, so that a variety of plants can establish on site. We prefer to test the soil before we start a rehabilitation project, so that one can incorporate any soil additives in the budget, if that allows.
Photo above: taking soil samples to be analysed for Cape Cairos site.
Limitations and how to deal with them in your plant list:
Budget
If you have limitations in budget, it is cheaper to have a larger seed component than plants. Seed germination is unpredictable and is variable across species. They can be blown around and also be predated on in the field after sowing. Even if you may have a mix of different species, it is often the pioneer species that dominate. Some of the climax species require seed treatment before sowing. Eg, many Protea species need smoke treatment for germination to occur. Possibly consider sowing the pioneers and planting the climax species. Then one has a better representation of plant species.
Plants in seed trays are cheaper than pot plants and they are easier to plant. However, plant survival of pot plants may be higher, as they have some soil to buffer the environmental element after planting.
Seed or plant availability
This is a general issue in the industry. There are not enough indigenous plants and seeds available for specific locations at affordable prices. If one can contract grow plants in nurseries, then one needs at least 1 year minimum to do this ahead of planting season.
Seeds from natural areas are more readily available. One needs permission from the landowner and permits to collect seed from Cape Nature. Processing and treating of seeds need to be done by someone with experience. Otherwise you may waste your time as they will not germinate.
Other limitations:
Time: if a restoration project needs to occur within a limited timeframe, this can put pressure on what plants you will use and what is available. In order to grow plants for a specific project, you need a minimum of 1 year. Seeds mature at different times for each species. Even the same species does not necessarily ripen at the same time each year. This is due to climatic variations, such as rainfall and temperature. We have a seed collecting calendar that we update as we harvest the seeds and this helps for planning into the future.
Permits for growing indigenous plants and harvesting seeds are needed from Cape Nature. This needs to be done well in advance.
Fire and other natural occurrences: Look into creating fire breaks around your rehabilitation site for the initial years of establishment. Make sure that the staff that work on site have safety measures in place in the fire season and policy with regards to smoking. Flooding can be devastating to a newly rehabilitated site and one can plant outside of the flooding season to mitigate this risk. Plants that naturally grow in the riparian zone should be able to handle flooding, as they develop root systems to handle this habitat. Understanding the plant that grow on different zones is crucial and focus on those plants if you are working on river systems.
Lack of knowledge or expertise: connect with other restoration practitioners, botanists and experts at conferences, like the Fynbos Forum https://fynbosforum.co.za/ and become members of SER (Society for Ecological Restoration) www.ser.org.
There are other limitations that we have not mentioned here or have not gone into much detail. If you have any questions, please comment below or email us. We do not have all the answers! So we might refer you onto others.
Keep in touch, check our facebook posts and send us an email to admin@greenintaba.co.za
References:
Holmes PM, Esler KJ, Richardson DM, Witkowski ETF (2008) Guidelines for improved management of riparian zones invaded by alien plants in South Africa. South African Journal of Botany. Vol 74, Issue 3, pg. 538-552 https://www.sciencedirect.com/science/article/pii/S0254629908001749
Comments