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Corridors and buffers: Claudia Gray on riparian zones in Malaysia and across the world

December 22, 2014
River riparian zone in oil palm plantation, Sabah, Malaysia.  Image: Claudia Gray

Claudia Gray
is a Post-doctoral Research Fellow in Ecology and Conservation at the University of Sussex.  Working in collaboration with PREDICTS, her work uses the project’s global biodiversity database to investigate how landscape management can help biodiversity conservation.

In the past, Claudia’s research has explored approaches to sustainable management of oil palm plantations in Sabah, Malaysia.  One of the things she’s found is that riparian buffer zones – the strips of ‘natural’ vegetation left intact along river banks – are not only important for conserving freshwater ecosystems, but that they can help provide habitat for land-based animals, too.

Claudia made this excellent stop-motion animation to explain her research on biodiversity in oil palm plantations.

Claudia is now looking to collate information on riparian zone management and legislation across the world.  We spoke to her to find out more.

Freshwater Blog: Why are riparian buffer zones important? 

Riparian buffer zones are legally protected in many different countries because of their beneficial impacts on freshwater ecosystems. In particular, the root system and ground cover they create prevents the run-off of sediment and reduces the loss of soil.  This also helps stop agricultural chemicals, such as pesticides or fertilisers, washing into the water. The plants can also take up and use some of the excess fertiliser that may have been applied to the surrounding landscape, further reducing the quantity that ends up the river or lake.  Keeping the levels of sediment and pollution in the water low benefits a whole host of freshwater species, including fish and macroinvertebrates like dragonflies or snails. There are also massive benefits for people living downstream, as they have cleaner water.

Riparian zone through a Malaysian oil palm landscape.  Image: Claudia Gray


Riparian buffers also prevent some of the destructive influence that rivers can have. Keeping vegetation alongside water bodies increases the stability of the river bank, reducing erosion and changes in the shape of the river channel. The riparian vegetation also helps to slow down the speed at which water flows into rivers; regulating the water level prevents extreme floods and droughts downstream. Again, these impacts benefit both the species living in and alongside the water channel, and the people that are using the water.

As well as preventing negative impacts, riparian buffer zones can provide valuable resources. The leaves and other organic material that falls from the vegetation into a water body provides food for the herbivorous species at the bottom of the food chain. Long-standing vegetation can also sequester and store carbon, helping to reduce CO2 levels in the atmosphere. The riparian habitat can also provide a home for vulnerable species that would not otherwise survive in productive landscapes. If an area of forest is cleared for agriculture, the riparian buffer will be one of the few remaining fragments where forest-dependent animals can live. If the riparian buffers also link up larger remaining fragments of forest or other habitat, they can act as corridors for movement and connect up populations that would otherwise be isolated.

At the moment these benefits for terrestrial species are much less well understood and the management of riparian areas does not normally take them into account. In my PhD  I wanted to document what riparian buffers are doing for the species that don’t live in the rivers, and how current policy might be changed to improve the conservation value of the riparian buffers for these species.

Riparian reserve in Belian.  Image: Claudia Gray

Riparian reserve in Belian. Image: Claudia Gray

What’s the current situation with riparian zone management in Malaysia?

In Malaysia, riparian buffer zones are protected by law, and the width of the buffer has to be between 5 and 50m (on each side of the river), depending on the size of the river. However, the legislation varies between states – for example, in the state of Sabah (Northern Borneo) where I was working, only 20m of vegetation must be retained on each side of the river.

Luckily, many land managers and conservation organisations have recognised that this small amount of forest doesn’t really achieve that much. Along some of the larger rivers more forest is protected than is required. For example, along the Kinabatagan river (a major river in Sabah) several groups are working to protect and restore at least 100m of forest on each river bank along the whole river (e.g. WWF Corridor of Life). The restoration is hard work as the seedlings can be easily strangled by vines or trampled by elephants, but some really great progress is being made. The World Land Trust recently raised a million pounds to help protect existing forest along the Kinabatangan, in collaboration with local NGOs, and they continue to support this project.

Unfortunately, riparian vegetation has not been successfully protected along all rivers in Malaysia. In some cases this is because deforestation happened before the legislation came into place, in other cases the land managers have failed to meet the requirements. As the oil palm industry has expanded across Southeast Asia, oil palms have been planted along the river bank in lots of plantations. However, there is hope that this can change.

Any plantation that wants to be certified as a sustainable producer by the Roundtable for Sustainable Palm Oil (RSPO), must have riparian buffers, or be in the process of restoring them. Where restoration is needed, the application of chemicals is halted, the existing palms are left in place after they would normally be replaced, and native trees are planted in the shade beneath them. At the moment, the buffer width required by the Malaysian implementation of the RSPO criteria is the same as the national requirement (5 – 50m), but little ecological information is available to inform this guideline. At the moment, the majority of research on buffer zones is from North America. That research is not very helpful for rainforest and oil palm landscapes in the humid tropics where the ecosystems are completely different. Fopefully, we will be able to obtain much more information on tropical riparian buffers in the next few years, to better inform the management guidelines. Ongoing work at the SAFE project (where my PhD was based) will be contributing some valuable insights into the ecological impacts of riparian buffers.

Riparian zone in the oil palm landscape.  Image: Claudia Gray

Riparian zone in the oil palm landscape. Image: Claudia Gray

Tell us about your current research into riparian buffers across the world: how, where and why are you undertaking this?

So, my interest in riparian policy across the world really came out of trying to put my PhD research in context. My results indicate that small increases to the required riparian reserve width in Sabah could provide large gains for biodiversity, and so we were interested in what the buffer width requirements were in other, similar countries. Lots of people have asked “So if thats whats going on in Borneo, whats happening in other tropical countries?“. This is especially important to know for areas where oil palm cultivation is still expanding.

When I started looking into existing riparian zone legislation, it quickly became clear that guidelines and legal requirements for managing riparian zones vary substantially. Some countries require a particular buffer width depending on the river size, others consider whether the river is home to fish species, whether it a seasonal or permanent river, or the topography of the surrounding landscape. There are many different criteria being used in different parts of the world. In some cases a particular management approach is a legal requirement, in others it is only a guideline adhered to on a voluntary basis. Requirements can also differ between privately and publicly owned land.

The task of trying to get to know whats going on is made more difficult by language barriers, so I started asking friends working in different countries if they know what the legislation is there. I’m still very much at the beginning to trying to find out what is going on in a range of different countries, and I’m trying to focus on the tropical regions where oil palm is likely to be grown. In the end, I would like to be able to put together a summary of what riparian legislation is in place in a range of different locations, and then compare this to the ecological information that is available there.

Tell us about the information you’re looking to collate on riparian zones.  What are you looking for, and how can people contact you?  What will you use the data for?

At the moment, I’m hoping to gather as much information as I can on riparian legislation and management, in as many parts of the world as possible. I’m particularly keen to hear about what is going on in tropical countries. So the information I’m looking for is any description of what is required for riparian zones, and if what is actually happening there matches up to it.

For example, if someone comes from, or works in a particular country, and they happen to know that native vegetation is protected by rivers, even that much information would be great. If they know how much is protected, and what factors determine the level of protection, that would be amazing. Even if only the really rough details are known, that would be really interesting. Also, if someone knows that native vegetation should be protected, but isnt really maintained in practice, or is only maintained in certain areas (e.g national parks), I’d also like to hear about that. I’ve heard about some really great riparian restoration projects too, and would be very happy to get links to or descriptions of those. They can be really inspiring and lovely to hear about.

The point of the ongoing work is to try and combine information on the legal reality and stories of riverside habitats with what ecological information suggests we should be doing. With more information on what is happening on the ground, it will be possible to work out where the ecological research matches up to what is going on in real life, and where there are really big differences. This should help show where riparian habitats and the species that require them need a lot more support.

If anyone would like to get in touch to know more or send some information, that would be excellent. I’d also really like to get in touch with anyone doing similar work. The best way to contact me is via email: claudia.gray(at)

Claudia’s website
Claudia on twitter

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