Longread

Biodiversity

A meadow full of flowers and butterflies, an ocean full of fish and coral... The concept of ‘biodiversity’ is a hot topic right now. But what does it actually mean? Why is it important, and what can we do with the knowledge it imparts? This is what the institutes of Wageningen University & Research are studying, so that we can contribute to applications in fields like agriculture and nature conservation, as well as the pursuit of broader goals like sustainable economic growth and human health. We do this from many different perspectives: from botany, microbiology, and animal ecology to economics and the social sciences.

What is biodiversity?

To put it succinctly, biodiversity is the variety of life in a defined area, whether that is a water droplet or a whole forest or even planet Earth as a whole. Biodiversity encompasses all types of plants, animals, and microorganisms, as well as the enormous genetic variation within the species and the variation within the ecosystems of which they are part, from wetlands to deserts. As this should make clear, the term comprises much, much more than flowers, trees, and the animals you can pick up and stroke. It is the total package of living organisms and systems, and the interactions between them. And as that suggests, it’s more than enough to keep the scientists working in this field busy describing, understanding and protecting biodiversity.

Biodiversity on a field edge
Biodiversity on a field edge

Why is biodiversity important?

One insect more or one insect less – what difference does it really make? How bad is it if a forest is cleared and replaced by a monoculture? ‘These are never simple questions,’ says Lawrence Jones-Walters, head of the Biodiverse Environments programme. ‘Their answers depend on a huge variety of factors. Let’s start by identifying what we need biodiversity for.’

Essentially everything we eat is directly or indirectly derived from biodiversity, either wild or domesticated. The bulk of what we build with, make medicines from, and use as industrial raw materials comes from biological resources. Many forms of tourism revolve around nature. ‘Biodiversity therefore represents enormous economic value,’ Jones-Walters emphasises. The UN Convention on Biological Diversity puts it as follows: ‘At least 40% of the world economy and 80% of the needs of the world’s poorest depend on biological resources. It is also important to understand that the richer the biodiversity, the greater the chances of medical discoveries, economic development and adaptation to new challenges like climate change.’

However, Jones-Walters is also quick to point out the intangible benefits of biodiversity. ‘For us, the biodiversity all around us has a huge intrinsic value,’ he says. ‘Research from all across the spectrum continues to show that people feel better and more productive in a green environment. People get better faster when their hospital room looks out over something green, for example. Patients with dementia or psychological problems do noticeably better when they have plants and animals around them. Landscapes also give us a tangible link to the past; they help us relax and get grounded.’

'Healing Gardens': a project where gardening seems to have a positive influence on the recovery of (former) cancer patients.
'Healing Gardens': a project where gardening seems to have a positive influence on the recovery of (former) cancer patients.

Working with nature, instead of against it

It should be clear that biodiversity is important – but what happens when it is under threat? ‘There are many examples of deterioration of biodiversity as a result of human activity,’ Jones-Walters explains. ‘A great many of these boil down to the relentless pursuit of short-term interests. Ultimately, however, the impact comes back around to us.’

He gives a few examples. Deforestation causes erosion, which means that fertile soil leaches away and once-fertile agricultural ground soon becomes unusable. Overfishing means that each catch is smaller than the last, and some species disappear entirely. Monoculture in agriculture makes our crops and our food supply more susceptible to pests, plant diseases and natural disasters.

‘The data shows that when you work with nature, instead of against it,’ Jones-Walters concludes, ‘you spend less and can count on more stable yields. This is something that is often difficult to get across to people. It’s our job as scientists to collect convincing examples of what not to do, and especially to show other, better ways of doing things and what the advantages are. On that, Wageningen is a world leader.’

In sustainable agriculture, monoculture makes room for mixed cultivation.
In sustainable agriculture, monoculture makes room for mixed cultivation.

The more diverse, the more stable: agriculture as example

Biodiversity is a natural defence against external factors that can threaten an environment: pests, diseases, pollution, and climate change, to name a few. For example, a mixed forest won’t be knocked down by a storm as readily as a tree farm full of nothing but pines, and a species-rich wetland does a great job of purifying waste water. There are other good examples from the agriculture sector. ‘Over the past century, we have seen small-scale, varied land use gradually giving way to endless fields of monoculture,’ says Wijnand Sukkel, researcher at Wageningen Plant Research, ‘but diseases and pests can tear straight through this kind of one-crop field. There’s nothing to stop a mould or an insect plague once it gets a foothold.’

Research at Wageningen has shown that along with the density of plants of a single species, another factor that determines the resistance of crops is the presence of natural predators of crop pests like spiders, parasitic wasps and predatory mites. ‘In a monoculture, you harvest all the plants in a field at the same time,’ Sukkel explains. ‘That also removes the predatory insects, when this is exactly what we want to keep. When you have alternating rows of different crops of plants, which you harvest at different times, then that gives the useful invertebrates a safe place to shelter, so they will quickly colonise the new crop.’

Something else interesting happens in fields with alternating crops: you see all kinds of interactions between the different crops, both above ground and beneath the soil. For example, the one will benefit from the compounds that the other excretes, and one crop will produce protective substances that will also defend the plants around it. ‘Every species has its own unique rooting and leafing system,’ Sukkel explains, ‘which means they use nutrients, water and light differently. In combination, that means a higher yield on average than if you had grown the same crops separately.’

Farmers in conventional agriculture have long tried to compensate for the disadvantages of monoculture – pests, insufficient use of nutrients – with increasing use of artificial fertilisers and pesticides. However, these approaches have other disadvantages, and are increasingly being discouraged. ‘That’s exactly why it’s important to be going back to more diversity in agriculture systems,’ says Sukkel. ‘They’re also better at resisting the effects of climate change, whether it’s extreme precipitation or drought.’

There is one challenge, however: modern farm machinery is designed with monoculture in mind. If you need to harvest crops row by row, this means you will need to use smaller machines. ‘Or robot systems,’ adds Sukkel. ‘There’s plenty of them out there, but they do mean an investment for the farmer.’ These new systems are particularly promising in areas where industrial agriculture is on the rise, like China where Wageningen is working with local institutions to study their effects and application.

The benefits of diversity in soil

There’s a secret that farmers and gardeners know: worms are good for the soil. They recycle dead material and keep the soil aerated, which means that water runs through it more effectively and the soil can ‘breathe’. In soil with worms, plants grow much better than in soil without them.

Along with worms, soil is home to a surprising diversity of nematodes, mites and springtails, ants, beetles and centipedes. And then there is what the naked eye can’t see: countless moulds and bacteria. Some organisms are beneficial to plant growth, recycling nutrients and improving the soil structure (earthworms and moulds), or keeping pathogens in check (like the many ‘good’ nematodes, moulds, and bacteria). Others can damage plants' health. All of them benefit (whether directly or indirectly) from the substances that the plants excrete. ‘It is a precarious balance that is still largely not understood,’ says Wim van der Putten, professor of functional biodiversity. ‘We really only know the tip of the iceberg.’

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The biodiversity in healthy soil is enormous: in just the top few centimetres of a single square metre of soil there may be as many as 400 earthworms and 20 million or so nematodes. A single teaspoon of soil will contain hundreds of metres of spores and 10 billion or more bacteria of 10,000 different types. ‘All together, they ensure that pathogens and fast-growing species cannot get the upper hand,’ Van der Putten explains. The bottom line, he says, is that a soil rich in biodiversity is the best soil for agriculture: it increases the productivity and reduces the risk of diseases and pests.

Watching what changes

In order to preserve biodiversity in any area, be it large or small, you first have to know what lives there and what the dynamics are. An important part of this is monitoring: systematic counting over the long term. ‘For some species, like birds or plants, this is relatively easy,’ explains Patrick Jansen, Associate Professor of Resource Ecology, ‘but for others, like mammals that are only active at night or are very shy, this is more complicated.’ That’s why researchers are very happy to have a tool that can observe mammals for them: the camera trap, a digital camera that automatically takes a photo or video when an animal walks by.

Jansen is the coordinator of CameraTrapLab, a virtual research lab that bundles the expertise of several organisations: alongside Wageningen UR, the Netherlands Institute for Ecology (NIOO-KNAW), Utrecht University, the Dutch Mammal Society and others. ‘Together, we work on concrete projects looking at a great many different areas,’ Jansen explains. ‘But another area that we are particularly focused on is method development.’ If you work smart, he explains, you can use the camera images to derive very specific information, like how many individuals of a given species there are in a given area, which lets you track how populations are changing over time.

For example, the projects are producing information about how large ungulates are moving across the Veluwe nature area, what animals eat carrion in the Oostvaardersplassen, and how small and medium-sized mammals are contributing to the spread of ticks.

‘Right now we’ve also got a fun project that involves people putting camera traps in their own back gardens,’ says Jansen. ‘These are gardens in all kinds of places, from rural areas to city centres. We hope to map out how animals are colonising and using the urban environment.’ This form of ‘citizen science’ serves a number of purposes, Jansen says. It gives scientists much more data than they could ever have collected themselves. ‘It’s also a way to get people excited about what’s happening in their own gardens, so they get more interested in taking care of their own environment.’

Camera trap for your backyard. Photo: Vincent Koperdraad
Camera trap for your backyard. Photo: Vincent Koperdraad

Restoring biodiversity

There are many places around the world where biodiversity is under threat. Knowledge of natural systems combined with knowledge of the various threats can help restore local biodiversity, and many Wageningen UR projects are designed to do that. One example is the work on corals in the Dutch Caribbean.

Coral reefs face a number of different threats, the most acute being climate change. As the world’s oceans become warmer and more acidic, many corals can’t keep up with the changes. Turbid waters caused by coastal erosion (the result of deforestation and construction) also cause problems for the coral. Meanwhile, pollution gives algae the chance to overrun the reefs, even as many of the fish species that feed on the algae that threaten coral are being overfished and disappearing themselves.

Wageningen researchers are studying what exactly corals need and how to protect the ones we have and even restore the ones we are losing. Restoration can be done by ‘planting’ live coral polyps, either on dead coral skeletons or on manmade structures. ‘We are looking for the ideal combination of factors to make cultivation as effective as possible,’ says Erik Meesters of Wageningen Marine Research in Den Helder. While in the wild you can have very little influence on these factors, what you can do is assess in advance whether a cultivation or restoration project in a given area will have a chance.

Meesters is working hard to find out why some colonies are more resistant than others. ‘I’m working with Lisa Becking from Animal Ecology, and we are looking at what genes are at work here,’ he explains. That will point us to the populations we need to look at more closely for cultivation. This is what we call “assisted evolution”.’ He’s also researching the impact of local lobster fisheries on the coral reefs at the Saba Bank, a nature reserve larger than the entire Wadden Sea. ‘If we find evidence of overfishing, then we can take action.’

Meesters and his fellow researchers are coordinating a three-year EU project that started last summer: RESCQ (Restoration of Ecosystem Services and Coral Reef Quality). The goal is to restore relatively large areas of the reef with corals cultivated on site in test fields. ‘We’re looking at a lot of different aspects,’ says Meesters. ‘What are the circumstances you should be cultivating in to give them the greatest chances of surviving in the wild? What is the optimum size of the coral branches you put out there? And how can you make sure that they reproduce sexually as much as possible, to maximise the genetic diversity?’

Another important goal of RESCQ is transferring knowledge to allow local people to take over the work. Ultimately, the project is intended to support itself by creating healthier coral reefs, which will generate income from tourism and sustainable fisheries.

Corals are cultivated in test fields. Photo: Erik Meesters
Corals are cultivated in test fields. Photo: Erik Meesters

Giving nature a helping hand

The North Sea is a relatively shallow sea, and its floor is largely sand, an ideal habitat for flatfish and bottom-dwelling invertebrates like starfish. However, other types of animals need a more solid substrate to attach to, or structures to hide in and hunt for food. ‘Not that long ago, the North Sea had a lot of natural oyster shoals,’ explains Joop Coolen of Wageningen Marine Research, ‘created naturally over centuries. After many years of intensive bottom fishing, however, these have largely disappeared. As a result, the North Sea is home to much less life than it used to have.’

Coolen is studying the role that manmade structures like drilling platforms, offshore wind turbines, shipwrecks and breakwaters can play in increasing local biodiversity here. ‘All kinds of animals head straight for them,’ he explains. ‘If you start with a sandy sea floor, and you just drop a single stone block there, you immediately double the biodiversity.’

Coolen describes all the things you find on a structure like the pile of an oil rig: ‘On the surface, you get a lot of mussels. Look at little deeper and you find the hydroid polyps: these are animals that grow in a tube-like form, which in a colony create a complex 3D structure that gives other animals a place to attach or a place to hide. Then there’s all kinds of anemones, in tremendous densities, and below that you have the soft corals.’ These hotspots of biodiversity attract fish, and they in turn attract seals and porpoises. Coolen has demonstrated by means of genetic research that mussel larvae use these structures as stepping stones for spreading out across the North Sea. ‘That means they can reach mussel shoals much further out from the coast, and that’s good for genetic diversity.’

The big takeaway for Coolen is that when an oil rig has done its job, removing all of it is not necessarily the best idea. ‘Whether fishermen will see any real benefits from it is still an open question, because in the North Sea it’s mainly the flatfish that are economically important,’ he says, ‘but the intrinsic value of the new biodiversity is huge. With artificial structures, we can do something to restore some of what we’ve lost in the last few centuries.’

Diving from an offshore gas platform. Photo: Joop Coolen
Diving from an offshore gas platform. Photo: Joop Coolen

The value of nature

Nature gives us a whole plethora of indispensable products and services, from clean water, wood, food, and medicine to oxygen generation, carbon absorption, water purification and coastal protection. Health, relaxation, inspiration and cultural identity are other benefits that nature also gives us, albeit less tangible. To protect these things effectively, and convince policymakers of their necessity, you have to put a price tag on them. In other words, you have to demonstrate what these services produce for us, as well as the flip side: what we lose or what we would have to spend if we were to lose these services.

That is no simple task. After all, what is clean air worth? What’s the price tag on a rainforest? Does it weigh up against the steps needed to combat climate change? Researchers at Wageningen are helping answer this type of question. One of them is Felix Bianchi, Assistant Professor of Farming Systems Ecology. ‘We’re doing research in China, where small-scale agricultural systems are still fairly common,’ he explains. ‘There, we see that wild pollinators like bees make the biggest contribution to yields.’ The pollinators do better on small-scale landscapes with field edges at which different types of flowers can be found. ‘Crops like rapeseed can also be pollinated by wind, but pollination by insects produces bigger and more stable yields,’ says Bianchi.

Bianchi and his colleagues are researching the impact of natural enemies of pest insects. ‘We discovered that in Chinese rice fields, frogs play a major role as predators of pest insects,’ he says, ‘but frogs are extremely sensitive to insecticides. Once you know that, then you can take into account in managing this type of agriculture system. That ultimately leads to higher yields with reduced pesticide use.’

Valuing nature

It’s not only in far-flung countries, but also right here at home that researchers, commercial partners and policymakers are working to discover new ways to create win-win situations: concepts that help both people and planet. Natuur verwaarden (Valuing nature) is one of the themes of Wageningen Economic Research.

The ancient relationship between agriculture and nature is very much a hot topic today. How do we create a healthy balance between using nature (for example, for recreation and agriculture) and preserving and managing nature? How can we shift to earning models that include nature as a standing element; an earning model that creates value for and with nature? A company may, for example, combine its agricultural production and environment with supplying services to society: from agro-tourism and farm shops to agricultural therapy, short chains and agrarian nature management.

This demands innovative entrepreneurs and policymakers with an appreciation for the importance of valuing nature. Wageningen Economic Research is investigating the options, and also supporting enterprises in developing new learning models and business concepts. Additionally, building on previous research into subjects like natural capital, biodiversity, inclusive agriculture and farm recreation, they have produced a list of frequently asked questions, like: how do you integrate nature into your earning model? Or, how do I make my business more nature-inclusive?

Bee landscape: everyone wins, including nature

The Netherlands is home to at least 358 species of bee, including the honeybee. Many of these have seen their numbers drop dramatically in recent years – not just the apiary honeybees managed by beekeepers, but more worryingly, the wild bees as well, says Sabine van Rooij of Wageningen Environmental Research. ‘They depend on what the landscape gives them for their food, shelter and building material,’ she explains. ‘That landscape has become increasingly poorer in flowers and the type of clutter where they can take refuge.’ Bees have also been suffering from the widespread use of pesticides.

A decline in bee populations is something that affects us as humans as well, because alongside honeybees wild bees are very important as pollinators. Of the 115 biggest food crops, 87 are absolutely dependent on pollination by bees – not only honeybees, but even more importantly wild bees. If this pollination was a service, it would represent a value of €15bn per year in the EU alone, and over €153bn per year worldwide.

‘Helping bee populations is not something you can do by planting a few flowers,’ says Van Rooij. ‘Wild bees need a landscape that offers both refuge and a sufficient supply of local food. Some species of bee are also very specifically dependent on a certain species of plant, and have a limited range. That means that to promote bee diversity, you need an approach at the landscape level, and that requires partnership between a number of different parties.’

Contours map of the Bee landscape in Zoeterwoude (in Dutch)
Contours map of the Bee landscape in Zoeterwoude (in Dutch)

With that as the background, Van Rooij has become involved in a unique project. Working with local residents, commercial parties, farmers, and governmental authorities, Wageningen Environmental Research, the EIS Insect Knowledge Centre and the Butterfly Foundation are developing a Regional Bee Landscape for the province of Zuid-Holland. This project is a part of the Green Circles initiative, in which Wageningen is partnering with Heineken and the provincial government of Zuid-Holland. The goal is to develop a carbon-neutral brewery, a sustainable economy, a rich natural landscape and a pleasant living environment for people.

‘For the Ministry of Economic Affairs, we’re also going to be looking in other regions over a five-year period at the effect of initiatives designed to help pollinating insects,’ Van Rooij says. ‘What are the things that various parties are doing for the bees, and which of those are actually resulting in more pollinators?’ Learning by doing is what it’s about – once we know what works, companies, provincial and local authorities and water boards will be able to apply those principles in other locations and other projects. ‘We can already do a lot more than people think,’ says Van Rooij, ‘but that’s why it really takes changing how people think. That’s what we want to contribute with this project.’

Nature in the city

Nature is under threat in many places, and nowhere is that clearer than in the urban environment. However, the urban environment may also offer the most dramatic opportunities for improvement. A few trees here, a beehive there, creative solutions for rainwater management and a little attention to urban wildlife corridors; it is in the city where a few small interventions can achieve a lot.

Wageningen UR is at the forefront of this area, and some of our work in it is showcased on the website ‘Opportunities for biodiversity in the city’. Its goal is twofold: to inform local residents, industry, and governmental institutions about the biodiversity in the city, and to offer inspiration and solutions for concrete actions.

‘In terms of biodiversity, the city is interesting for two reasons,’ says Alterra researcher Robbert Snep, who developed the website. ‘Increasing numbers of species are discovering the city as a place to live, and the city is a perfect place to inspire and inform our urban society about biodiversity issues. This website is one of the ways we want to do that.’

The site has two main parts: on the one hand, a map of the city showing the opportunities for biodiversity in the individual areas; on the other, a list of urban parties that can have an impact on biodiversity and why that is relevant. The site is intended mainly as a portal, with various categories of links pointing the way to more information. This portal function is important, because at present a lot of information about urban nature is fragmented and hard to get a grip on. Now, for anyone with an interest in the city (whether individual, company, governmental institution or other organisation), specially tailored and compiled information about promoting biodiversity in the city is just a click away.

Working towards resilience: from knowledge to solutions

‘Protecting biodiversity remains controversial,’ concludes Lawrence Jones-Walters, head of the Biodiverse Environments programme. ‘Take the example of the current government in the United States: it’s obvious that they don’t believe that nature has a value. On the other hand, it’s overwhelmingly clear that nature benefits people, and people want to have nature around them. Extraordinary landscapes give people an enormous sense of pride. When there are nesting spoonbills, or cranes, everyone is so happy, and not just because of what they mean for tourism.’

Jones-Walters is convinced that the crux issue is working towards resilience: making sure that ecosystems are robust enough to handle an incident when it happens; making sure that species can cope with changing circumstances. They can only do this if they are given enough room to do so, and if the underlying ecological conditions are met. ‘That’s one of our biggest challenges,’ says Jones-Walters, ‘because doing that requires a lot of knowledge. What is resilience exactly? What is it made of, and how can you make it?’

On these questions, Jones-Walters is confident that Wageningen can take a leading role. ‘Wageningen UR is extremely diverse and international,’ he says. ‘We can draw on the knowledge, experience and cultural backgrounds of a broad spectrum of researchers. Together, they have the very best knowledge of how an ecosystem works, how to restore biodiversity and how to adapt to climate change. That’s the knowledge that you can use to bridge the gap between science and policy and implementation. Yes, I’m absolutely optimistic about that.’