Before you became President of Glynwood Center for Regional Food and Farming, in Philipstown, NY, you were Director of Harvard’s Center for Health and the Global Environment. The relationship between environmental health, human health, and public policy advocacy has been your key focus and concern. What would you like to contribute and achieve at Glynwood with your leadership during these challenging times?

When I was at Harvard, I became more and more interested in the connections between the natural world, agriculture, and human health. That seems pretty obvious in terms of how we depend on nature to grow and raise our food, and we have to eat to survive, so it seems like a pretty direct connection. Yet I think there still exists a lot of disconnect between human health, public health, food, and agricultural systems in the natural world. What I hope to do at Glynwood is to prove that regional food is a model that can be replicated nationally and that a regional food system supports healthier ecosystems, human health, community health, local prosperity, and food sovereignty in a way that our centralized commodified food system is failing to do. 

Yes, our problems are interlinked and so are solutions. The past three COVID years produced a mass exodus from New York City, which has pushed up farm prices in the surrounding areas to extreme highs, pricing farmers out of business. This has become a real issue in the Hudson Valley where wealthy people are driving up farm and land prices and they don’t farm. Farmers are being displaced and leasing the land from the new owners, bringing the idea of a new type of feudal system to mind for many. Is there any dialogue within Glynwood about how to address this escalating situation?

I do think that land access is one of the main barriers to building a regional food system with small and mid-size farms that we want to see, that are traditionally practicing regenerative agriculture and fostering food sovereignty. Land access has been a problem consistently in the Hudson Valley. Because more people are buying property in the Hudson Valley, it’s been a difficult moment for land access. However, at the same time, during the pandemic, people really discovered local food. Some folks have been scared to go into a grocery store, or the centralized food supply system was so broken that they sought out local food. So, I think there’s a little bit of a buffer there.

And then there are organizations like Glynwood. We absolutely help farmers find affordable land. There are resources through Glynwood and through other partners, that make land more affordable, including no or low-interest loans, or easements on the land that make it only available to farmers or folks who want to not develop the land by putting a house on it, for example. So, there are definitely tools. There’s always more to do, but there are lots of partnerships. We work with American Farmland Trust, for example, on their efforts to match land with farmers. Increasingly, private landowners who own historic agricultural land want to see that land go back into production and might build a relationship with a farmer to be able to have a lifelong lease or a very low-interest lease on their land so that while they own the land, the owner can be a non-operating farm owner and work with a farmer that might not be able to afford their own land yet.

Do you have any success stories that you could talk about?

There are lots of success stories. One of our board members owns some farmland in the Hudson Valley and has consistent farmers on that land that run their own businesses. So, the businesses are the farmer’s businesses, and the landowner is simply a landowner. There are farms like Obercreek that we work with, where they own the farmland, and they retain the farm businesses. There are several farmers that live and work on that farm and can get high-level management skills.

Through our Farm Business Incubator program, we’ve supported several farms in the Hudson Valley that are just starting out, and some of those are pieces of land that we have helped them find through partnerships with Open Space Institute or Scenic Hudson. And we help them ensure that their farm business is viable. I know that there’s been a lot of conversation about failure stories, but there are success stories that we’ve been involved with.

Can you talk more about the regenerative agricultural movement and management movement and why it’s so important in the world right now in conjunction with everything else that’s going on, including the gathering dark clouds concerning the future of food and how we are going to feed everyone?

Regenerative agriculture is sort of a newly popularized term for a suite of practices that are pretty old. I could even argue that it’s a lot of indigenous wisdom that has been recently popularized. At its core, it’s about working with the soils to capture more nutrients and to be able to sequester more carbon, with less disturbance, so no-till or minimal till, those sorts of sustainable practices. That’s important for a long-term view of land stewardship, which again has been a hallmark of the good food movement, in stark contrast to a really commodified, centralized agricultural system that has prioritized profits, efficiency, and scale over land stewardship. Obviously, as we are facing a climate crisis, we must be able to sequester more carbon in the soil, build resilient systems that will weather the extreme weather events we’re experiencing, and maintain a much longer-term view than short-term returns.

I often get asked if those kinds of systems can feed the world, and I feel that we could do a lot better than what we are doing with a global commodified center. We’re seeing the effects of that system right now in terms of the conflict in Ukraine, the effect that’s having on grain, which is an example of a global commodified market. One of our programs here in Glynwood is to foster regional grain production in the Northeast. If we all had regional food systems that were resilient and regenerative, we would stand a better chance of feeding ourselves rather than a very centralized system that is vulnerable to physical, cultural, sociopolitical struggles.

Glynwood is training young farmers through apprentice programs to be able to address issues locally and have them understand how it connects to the bigger picture. However, when I last visited Glynwood, I didn’t see any beekeeping. Isn’t Glynwood active in bee conservation?

We have had bees in the past, and we actually have an apprentice who’s been trying to catch a swarm this season. I don’t think there are bees residing right now, but she’s keenly interested in beekeeping. So, at the moment, Glynwood doesn’t have bees because our beekeeper moved on to another area. But many of the farms that are in our programs throughout the Hudson Valley have apiaries and integrate beekeeping into their systems. We just happen to be in between beekeepers, while there is an emerging beekeeper who is in need of bees.

So, that’s part of the picture?

Yes, of course.

But certainly, it has to be.

We’re blessed here physically at Glynwood . As you’ve seen, we are surrounded by tens of thousands of acres of protected land. So there’s a lot of biodiversity and pollinators that are just naturally here. So that’s also wonderful for this property in particular.

I think one of the biggest attributes of regenerative agriculture is that it prioritizes soil health and microbiology. Soil microbes are all-important in fixing nitrogen and unlocking phosphorus. Glynwood is doing a wonderful job of training young farmers in this type of regenerative soil maintenance. Are the benefits of this food production system something that you can pass on to small backyard framers?

Sure. We monitor our soil through simple soil tests that are available through Cornell in New York, for example. Yale also has a program. A lay gardener can find ways to learn about their soil and then have it monitored easily. In the past, we have done workshops and soil health field days in soil management for the general public, and we teach about soil stewardship. But we certainly do in our farmer training, —and region-wide—not just for the farmers locally. There’s been a wonderful collaboration emerging in the Hudson Valley dedicated to educating folks about soil science, mostly professionals, not necessarily lay folks. But I think there are many other programs and resources. One being Dr. Masoud Hashemi’s of Umass-Stockbridge School of Agriculture, who is one of the leaders in the field of soil health and microbial activity and has instructed us here.

What other organizations working in health, food, and the environment do you admire, and why?

UC Santa Cruz, my alma mater, is one. They have an excellent farmer training program where students are resident on the farm for a year, and the curriculum is really solid. I also really admire what they’re doing in terms of formal curriculum around farming– such as food sovereignty and food justice. 

I’m a great admirer of Soul Fire Farm in Petersburg, New York, that’s educating Black farmers specifically and really thinking about food justice and food sovereignty. Quivira Coalition, based in Santa Fe, New Mexico, is another organization building food justice capacity. They provide farmer-rancher training and sharing of information, ideas, and resources with the general public. Intervale Center is a Vermont-based incubator program that we’ve learned a lot from over the years. The program gives land access to new entry farmers in a collective, cooperative way. I think they are doing a great job. There aren’t many organizations that are centering on regional food. Glynwood is really unique in that way. But there are organizations like the ones I mentioned, that are either addressing farmer training or food sovereignty. An international organization that I like quite a bit is called A Growing Culture that is working globally on serving smallholder farmers who are mostly women, and they’re doing that very thoughtfully. 

Well, what are you most proud of with Glynwood’s efforts?

I wouldn’t have Glynwood take all the credit for this, but I am very proud of how we have changed or helped evolve the narrative of good food away from an elitist foodie perspective and more towards a food sovereignty perspective. I think if we rewind 10 years ago when I started here, it was sort of bougie. The good food movement was primarily catering to wealthy privileged folks and featured white tablecloth restaurants and four-hour meals, and that sort of business. And that’s not what I’m interested in, and I think it’s taken time for folks to understand that high-quality consciously grown or raised food should serve all of us and not just the very few.

This has increasingly shown up in our programming here at Glynwood, but beyond that, the conversation is evolving toward food as a human right and as a social justice issue, rather than just joyful, flavorful stuff, which is of course why it’s so great. But it’s really moved beyond that, and I’m proud of Glynwood’s role in the evolution of that perspective.

That is very important. And I feel like you’re somebody who clearly has their finger on the pulse of the Hudson Valley region, but also nationally and internationally, because we’re all facing very similar problems around the world. And I’m wondering who the thinkers and the writers are that have been major influencers on you and your thinking.

There are so many. Joan Gussow, Alice Waters, and Mary Cleaver are three women that come to mind that were early influences on my thinking. Fred Kirschenmann is also really important. I encountered them, and Frances Moore Lappé, the author of Diet for a Small Planet, early in my interaction with the food movement. 

Lately, I’ve been really impressed with my partner’s podcast Food with Mark Bittman. He highlights awesome writers and thinkers, such as Leah Penniman, the co-founder of Soul Fire Farm. Her book Farming While Black was really eye-opening and important for me. So was Marya Rupa and Raj Patel’s most recent book, Inflamed: Deep Medicine and the Anatomy of Injustice.Laura Lengnick, who’s our director of agriculture, also recently published a second edition of her book, Resilient Agriculture: Cultivating Food Systems for a Changing Climate.

Are there things individuals can do to help the regenerative agriculture movement?

There’s nothing better than planting your own seeds and serving the food you have grown to the people you love a few months later. I totally encourage folks to do that if they can. It does take some time and some of us don’t have that privilege of time available. I would say to those folks that one of the best ways you can support your regional farmers, have fun, and improve your health is by joining a community-supported agriculture farm, that’s a CSA farm.

According to that model, you typically pay upfront for a season’s worth of food, and you pick up your weekly share as an investor in that farm. I grow some food, but I also participate in our CSA, and it’s synergistic because I’m able to ask the farmers questions about who’s eating my basil and such. When I’m struggling with my garden, it’s great to be able to get professional answers. Some CSAs offer educational activities for their members.

CSAs are good for the farmers and so good for the eaters in terms of health outcomes.

Learn more: Recommendations from Kathleen Finlay:
Food by Mark Bittman (podcast)
Healing Grounds by Liz Carlisle (book)
Resilient Agriculture by Laura Lengnick (book)
Animal, Vegetable, Junk by Mark Bittman (book)
The Edible Magazines
Heritage Radio (several podcasts)

Kathleen Finlay is a leader in the regenerative agriculture movement. She has been President of the nonprofit organization The Glynwood Center for Regional Food since 2012. Previously, Kathleen was a Director of Harvard’s Center for Health and the Global Environment. She is also the founder of Pleiades Network, a membership organization working to advance women’s leadership in the sustainability movement.

This article offers a glance into the olfactory world of nature, in which we first discuss nature and its odors, then describe the scents that these odors produce. The difference between odors and smells is that odors are molecules in the air and smells are the mental representations of these odors in our minds. That there is an (often ignored) distinction between these two concepts can be a little confusing, because in color perception, we use the same word for both concepts. The term “color” refers to both the physical pigments in the environment and how they appear to us mentally. In comparison, the olfactory world is much more complex.

Part I: Nature and Its Odors

Most odors are generated by living things: plants, animals, and microorganisms. Some nonliving things also produce odors. Ozone and formaldehyde are formed by atmospheric processes, and hydrogen sulfide is produced by volcanoes, but essentially, the world was odorless before living things came along and started producing a wide variety of different odorous molecules. Roses alone release more than 250 different molecules. These molecules contribute in complex ways to the rose smell. Many of them contribute very little, while the mixture of beta-damascone, beta-damascenone, and (-)-cis-rose oxide, which combined make up less than 1% of the total volume of rose essential oil, is necessary for the rose’s characteristic scent.

The complexity of the possible mixtures of odor molecules is staggering. There are over 30 billion odorous molecules and around 2 million of them have so far been found in nature. 

A common misconception, dating back to Aristotle’s writing on scent, is that odor molecules are components of their source objects and detach to become airborne, like water molecules evaporating from a lake. In reality, rose odor molecules are actively produced in certain parts of the plant, transported to other structures where they are stored, and then released in appropriate situations. Enzymes that have evolved specifically for this activity make it feasible for this energy-intensive process to occur. A rose does not have an odor, it makes an odor. And it does make that odor for a reason. It performs an adaptive function for the rose rather than being a byproduct of being a rose.

Odors as Signals

A well-known function of flower odors is to attract pollinators. The odor is a signal the flowers send to potential pollinators, usually insects. But pollinators are not the only recipients of plants’ odor signals. Some plants also use odors to signal to other plants. Black Walnut (Juglans nigra) gives off a molecule called juglone that repels other plants, thereby reducing competition for space, water and nutrients. Other trees, such as sugar maples, sycamore, and red oak also produce allelochemicals to assure their survival. When grass gets damaged, it releases molecules that elicit the typical “cut-grass” smell. These molecules are signals for other grass that the plant is under attack. In animals, it would be called an alarm pheromone. 

Potential predators are also common recipients for plants’ odor signals. For example, caraway seeds make the chemical carvone that gives them their distinct scent in order to repel insects and other potential animals which may eat them. Ironically, humans like the flavor of caraway and producing carvone has increased caraway’s danger of being eaten by people. The same dynamic is known for the molecules that give chili peppers their spiciness. Their function is to deter animals from eating them, but humans have developed a masochistic liking for the taste and started eating chili peppers.

When a plant or animal dies, bacteria break down the large, synthesized odor molecules into smaller ones. These smaller molecules are responsible for the smell of decay or fermentation. They do not have a function but are a byproduct of the bacteria breaking down larger molecules. Plants may then use the small molecules produced by bacteria again to make larger molecules and complete the cycle. 

Citrus Fruits

Different plants create various odor molecules, and as a result, they all have a distinct smell. However, sometimes plants have similar smells because they produce similar mixtures of molecules. The fruits of citrus plants are a well-understood case study for the contribution of odors to smells. All the citrus fruits available in a supermarket—oranges, limes, lemons, grapefruits—are the result of humans crossing the four naturally-occurring citrus fruits: pomelos, true mandarins, citrons, and small-flowered papedas. For generations, farmers have hybridized these species to generate hundreds of new variants that combine the characteristics of the four ancestral citrus fruits. The cross between a pomelo and a mandarin, for example, results in a sweet orange, and if a sweet orange is crossed again with a pomelo, the result is a grapefruit. In this area defined by the ancestral species, fruits may be moved within this spectrum. These ancestral species produce different odors because they evolved different odor-producing enzymes. As the plants are hybridized, these enzymes can be combined in novel ways, thereby changing what odor molecules are being produced. The scents of various citrus fruit varieties differ as a result of the recombination of odor synthesis pathways. All citrus fruits share many of the odorous molecules that they release. For example, limonene, a molecule with a citrusy, fruity smell, makes up more than 50% of the essential oils of most citrus fruits.

Common elements like limonene are responsible for the olfactory qualities that are shared by all varieties of citrus fruits. But of course, not all citrus fruits have the same smell, it is generally easy to distinguish the smell of an orange from the smell of a grapefruit. These differences in the odor of citrus fruit varieties are due to molecules in the mixture that are only found (at relevant concentrations) in those specific kinds. The molecule nootkatone, for example, is only found in grapefruit, and it is responsible for the characteristic bitter aroma of grapefruits. The combination of shared and exclusive odor molecules explains the similar yet unique smells of citrus fruits.

Orchids

All citrus fruits are closely related, but there are also cases of widely different plants which produce the same odors. These are examples of convergent evolution, which happens when unrelated species independently evolve the same solution to a problem. The textbook example is the independent evolution of wings for flying in bats, birds, and insects. When it comes to plants, orchids are well known for producing a wide variety of odors that often mimic those of other plants. There are orchid species that smell like piña colada, white chocolate, vanilla, strawberry, or rhubarb. These orchid species have evolved ways of synthesizing the same molecules, and hence comparable scents of other unrelated plant species.

Not all orchids mimic the smell of other plants. Some orchids smell like rotting flesh to attract pollinating insects that usually eat decaying meat. Others attract bugs by feigning to be a female who is available and emitting an odor similar to the pheromones of insects. Orchids are masters of mimicking smells found in the natural world and using them for the purpose of getting pollinated. There is a type of orchid in Korea that mimics the alarm pheromone of bees, which attracts insects that prey on bees. The predatory insects smell what they think is an injured bee and, searching for the easy prey, get trapped in the orchid and pollinate it.

Part II: Smelling Nature

For an odor to elicit a smell, it has to be smelled by somebody. This happens when the odor molecules emitted by plants reach our nose. On the very top of the nostrils, between the eyes, the olfactory nerve enters the nasal cavity where it terminates in the olfactory epithelium. The olfactory nerve consists of different types of sensory neurons. Each type expresses one of hundreds of different odorant receptors, which are the molecules that bind to odor molecules. The neurons of the olfactory nerve, which are directly exposed to the unfavorable environment of the nasal cavity, continuously die and regrow. 

Combinatorial Code

In our nasal cavities and the air surrounding us, various combinations of odorous airborne molecules are present at any one time. Different molecules from this mixture bind to various odorant receptors, thereby activating the sensory neuron. The sensory neuron then sends a signal up the olfactory nerve, through the skull, into a brain structure called the olfactory bulb. The olfactory bulb consists of spherical structures called glomeruli. In each glomerulus, sensory neurons of the same type converge. Every molecule will activate a combination of receptors. To give a hypothetical example, vanillin may activate receptors 73, 115 and 299, the activation of the receptor combination 73, 115, 299 therefore signals to the brain that vanillin molecules are being encountered. This is known as the “combinatorial code” of olfaction: each type of odor molecule activates several receptors, and each receptor is activated by several types of odor molecules, resulting in a unique combination of activated receptors for each type of odor molecule.

Odorant Receptors

The odorant receptor gene family is the largest in our genome. Humans have, depending on the counting method, 400 or 800 odorant receptor genes, compared to only three-color pigments. Whether we count 400 or 800 odorant receptor genes depends on whether pseudogenes are counted. Pseudogenes are genes that have accumulated mutations that rendered them non-functional. When scientists first sequenced the human genome and realized that half of our odorant receptor genes are pseudogenes, they speculated that this was a consequence of the declined importance of olfaction for our species. If our sense of smell no longer plays a role in our survival and reproductive fitness, there is no selective pressure against deleterious mutations in odorant receptor genes and these mutations can accumulate, turning the genes into pseudogenes. However, after the genomes of various other animal species had been sequenced, it became clear that odorant receptor pseudogenes are very common in almost all species, including those well-known to rely heavily on their sense of smell.

Specific Anosmias

Many odorant receptor genes are found as a functional variant in some people and as a non-functional variant in others. In these cases, some of us carry the gene while others carry the pseudogene. People who carry the non-functional variant sometimes have reduced sensitivity to the odor molecules the receptor binds. This is a condition known as “specific anosmia” or “partial smell blindness.” Somebody with specific anosmia has a normal sense of smell except that they cannot smell a specific group of molecules or smells, such as musk. Specific anosmia is the olfactory version of partial color blindness (such as red-green color blindness), which is also caused by genetic variation in the gene for the protein interacting with the stimulus. However, there is a conceptually very important difference between specific anosmia and color blindness: in color perception, over 90% of the population have functionally the same set of photoreceptors. In olfaction, everyone has a unique collection of odor receptors, with the exception of identical twins. There is no “normal” set of receptors and therefore also no standard way of perceiving odors. As a result, an odor does not have a smell. Instead, a smell is assigned to an odor, and which smell somebody assigns to a specific odor depends on which set of receptors they are smelling it with. If two people assign different smells to the same odor, there is no principled way of determining who is right. Because they can both be right.

We don’t normally recognize that we have a specific anosmia because almost all odors we encounter are mixtures and when we are less sensitive to a component of the mixture, we are still able to smell it. Differences in the perception of the aroma of cilantro, and inability to smell the characteristic odor of urine after eating asparagus, are two examples of a specific anosmia that has noticeable effects on perception and behavior in everyday life. Another example is the specific anosmia to the odorous steroid androstenone and related components. These components, which are odorless for many, but have an unpleasant smell of sweat and urine for most, are found in the meat of uncastrated male pigs. People with this specific anosmia are less likely to detect a taint in such meat and are therefore more likely to eat it.

Influence of Background Beliefs

How we perceive a given odor through our sense of smell depends strongly on our odorant receptor variants. How we judge odors on the other hand is deeply affected by the context and our previous experiences. The various reactions people have to certain odors provide insight into how deeply these aspects might influence opinions—like pork, fermented food, and spices like garlic—or cigarette smoke in different populations.

The influence on background beliefs on olfactory judgments has been confirmed in controlled studies. In one of those studies, subjects were asked to rate the smell of isovaleric acid, a molecule that is found both in the odor of parmesan cheese and dirty gym socks because it is produced by bacteria that thrive in both environments. (The artist Sissel Tolaas once isolated bacteria from David Beckham’s dirty gym socks and used them to make cheese.) For the study, one group of the subjects who were judging the smell of isovaleric acid were under the impression that the source of the molecule was sweat, while another group was under the impression that the source was cheese. Depending on what they believed to be the source of the odor (the real source was a chemical factory in which the isovaleric acid was synthesized), subjects assigned dramatically different pleasantness ratings to the odor.

Influence of Other Modalities

In another study that demonstrates the tremendous impact of non-olfactory factors on peoples’ judgments of odors, researchers used students of wine making at a school in Bordeaux as their subjects. These wine experts were asked to smell (but not taste) three different wines and describe their aroma by picking descriptors from a list. One wine was a red wine, the other a white wine, and the third the same white wine but colored red with odorless food coloring. The subjects’ description of the odor of the white wine with the red coloring was much more similar to the description of the odor of the red wine than to the description of the odor of the white wine. This means that a wine’s description of its aroma was influenced more by its color than by its smell.

While the results of these experiments are clear and dramatic, the interpretation of the results is difficult. Does the white wine actually smell different when it is colored red, or does it smell the same but the smell is judged differently? I believe the latter is the case. The students knew which descriptors are commonly used for red wines: tar, leather, plum, cherry—and which descriptors are commonly used for white wines: honey, apricot, apple, hay. They did not want to look foolish by using white wine descriptors to describe a red wine. Their background knowledge, rather than helping them with the task, was entrenched enough to overrule the sensory evidence. Designing an experiment that would confirm or refute this interpretation of the result is challenging, though.

Influence of Previous Experiences

The studies with the isovaleric acid with various labels and the wine with different colors show the impact of background beliefs and sensory input from other modalities on accounts of olfactory perception. In addition, these reports are shaped by previous experiences with the smell. The pleasantness of a smell associated with a food or drink that has caused food poisoning, for example, will be judged very differently before and after it caused the discomfort. These effects can be astonishingly long-lasting and difficult to overcome. Even scent experiences in the womb, before being born, impact lifelong attitudes towards the experienced odors. Researchers in France demonstrated this by recruiting pregnant women and dividing them into two groups. One group was instructed to regularly eat anise-flavored candy throughout their pregnancy, whereas the other group was instructed to avoid such candy. When the newborns, minutes after they were born, were tested for their response to anise odor, they demonstrated the predicted differences between the two groups. Babies of women who consumed anise-flavored candy during pregnancy displayed attraction and curiosity towards the odor whereas babies in the other group were indifferent to the scent.

This short glimpse into the world of odors and smells shows that the odors in nature, the mental representations elicited by them, and the verbal reports about the odors are more complex and multilayered than we usually appreciate. The smells of nature, especially those that are in danger of disappearing, are deserving of our respect and appreciation and we must ensure that they can be experienced by future generations.

Dr. Andreas Keller received his PhD in Genetics from the Julius-Maximilian-University in Wuerzburg, Germany, and holds a second PhD in Philosophy from the City University of New York. He continues research in olfaction at Rockefeller University and is the founder and owner of the NYC art gallery Olfactory Art Keller.

https://www.instagram.com/olfactory_art_keller/

Insects are critical to the future of our planet. They help to keep pest species under control and break down dead material to release nutrients into the soil. Flying insects are also key pollinators of many major food crops, including fruits, spices and – importantly for chocolate lovers – cocoa.

The growing number of reports suggesting insect numbers are in steep decline is therefore of urgent concern. Loss of insect biodiversity could put these vital ecological functions at risk, threatening human livelihoods and food security in the process. Yet across large swathes of the world, there are gaps in our knowledge about the true scale and nature of insect declines.

Most of what we do know comes from data collected in the planet’s more temperate regions, especially Europe and North America. For example, widespread losses of pollinators have been identified in Great Britain, butterflies have experienced declines in numbers of between 30 and 50% across Europe, and a 76% reduction in the biomass of flying insects has been reported in Germany.

Information on insect species numbers and their abundance in the tropics (the regions either side of the Equator including the Amazon rainforest, all of Brazil, and much of Africa, India and Southeast Asia) is far more scarce. Yet the majority of the world’s estimated 5.5 million insect species are thought to live in these tropical regions – meaning the planet’s greatest abundances of insect life may be suffering calamitous collapses without us even realising.

The largest of the 29 major insect groups are butterflies/moths, beetles, bees/wasps/ants and flies. Each of these groups is thought to contain more than one million species. Not only is it near-impossible to monitor such a vast number, but as many as 80% of insects may not have been discovered yet – of which many are tropical species.

Responding to these knowledge gaps, researchers at UCL’s Centre for Biodiversity and Environment Research have conducted one of the largest-ever assessments of insect biodiversity change. Some three-quarters of a million samples from around 6,000 sites worldwide were analysed in our study, adding up to nearly 20,000 different species in all.

Insects are facing an unprecedented threat due to the “twin horsemen” of climate change and habitat loss. We sought to understand how insect biodiversity is being affected in areas that experience both these challenges most severely. We know they do not work in isolation: habitat loss can add to the effects of climate change by limiting available shade, for example, leading to even warmer temperatures in these vulnerable areas.

For the first time, we were able to include these important interactions in our global biodiversity modelling. Our findings, published today in Nature, reveal that insect declines are greatest in farmland areas within tropical countries – where the combined effects of climate change and habitat loss are experienced most profoundly.

We compared high-intensity farmland sites where high levels of warming have occurred with (related) areas of natural habitat that are little-affected by climate change. The farmland sites possess only half the number of insects, on average, and more than 25% fewer insect species. Throughout the world, our analysis also shows that farmland in climate-stressed areas where most nearby natural habitat has been removed has lost 63% of its insects, on average, compared with as little as 7% for farmland where the nearby natural habitat has been largely preserved.

Areas our study highlights as particularly at risk include Indonesia and Brazil, where many crops depend on insects for pollination and other vital ecosystem services. This has serious implications for local farmers and the wider food chain in these climatically and economically vulnerable areas.

Cocoa, midges and deforestation

Eighty-seven of the world’s major crops are thought to be fully or partially dependent on insect pollinators, of which most tend to be grown in the tropics. Cocoa, for example, is primarily pollinated by midges, a group of flies infamous for bedevilling camping trips in Scotland and other parts of the northern hemisphere. In fact, midges play a vital and under-appreciated role in pollinating the cocoa needed to make chocolate.

The majority of cocoa production takes place in Indonesia, Côte d’Ivoire and Ghana. In Indonesia alone, the export of cocoa beans is valued at around US$75 million per year. Most cocoa production is carried out by smallholders rather than big plantation owners, and many farmers are dependent on this crop for their livelihoods. While it is critical to understand whether insect losses will make things worse for cocoa and its farmers, we have very little knowledge of the state of insect biodiversity in tropical countries such as Indonesia.

Cocoa production in the region is already being stressed by adverse weather events that may be linked to climate change. Warming temperatures and changing rainfall patterns are implicated in changes in the growth, pollination and bean production of cocoa plants.

Agriculture is one of the major industries for the people of Indonesia, particularly in rural regions, with large areas being cleared for the production of key crops, also including palm oil. This has resulted in deforestation of extensive areas of rainforest, increasing the risk to many rare and endangered species such as the orangutan, as well as less well-known species including many insects. 

Tropical regions are under considerable threat, primarily as a result of agricultural expansion – often to meet increasing demand from countries outside the tropics. International trade has been shown to be a major driver of deforestation in these regions, with forests in Southeast Asia, East and West Africa and the Amazon particularly vulnerable. Brazil’s and Indonesia’s high levels of deforestation are attributed to the production of commodities for export including soybean, coffee, palm oil – and cocoa.

The threat of climate change

Habitat loss is known to be a key threat to biodiversity, yet its impact on insects is still under-studied, and assessments of tropical species tend to be very rare. One study found that forest-dependent orchid bees in Brazil have declined in abundance by around 50% (although it only sampled their numbers at two time points). Orchid bees, found only in the Americas, are important pollinators of orchid flowers, with some plants being entirely dependent on this insect for their pollination.

Adding to the challenges of deforestation and other, longer-term habitat changes, is climate change. This fast-emerging threat to insect biodiversity has already been implicated in declines of moths in Costa Rica and bumblebees in Europe and North America. Rising temperatures and increasing frequency of extreme weather events, such as droughts, are just two manifestations known to be having a harmful impact on many insect species.

It is predicted that climate change will have a particularly big impact in the planet’s tropical regions. Temperatures in the tropics are naturally quite stable, so species aren’t used to coping with the fast changes in temperature we are seeing with climate change. Again, though, our ability to understand how this is affecting tropical insects is hampered by a lack of data for these regions. Almost all of the available data comes from only a few very well-studied groups of insects – in particular, butterflies, moths and bees – while many other groups receive very little attention. Despite a big increase in studies of insect biodiversity change, there is still much we don’t know.

Insects normally missed

To help address this knowledge gap, our study has assessed three-quarters of a million samples of insects from all over the world. Of the 6,000 sites included, almost one third are from tropical locations. Our samples of nearly 20,000 different insect species include beetles, bees, wasps, ants, butterflies, moths, flies, bugs, dragonflies and other, less well-known groups.

This was made possible through the use of PREDICTS, a biodiversity database which brings together millions of samples collected by researchers all over the world. PREDICTS records biodiversity in natural habitats and also in areas used by humans for growing crops, among other purposes. It is one of very few global databases that allow us to study biodiversity changes across the whole world.

While our 20,000-strong sample represents only a fraction of the vast diversity of insect species, it is still a sample from more sites than have ever been studied before. We were particularly interested in using it to understand how habitat loss and climate change play off each other to affect insect biodiversity, and were able to include these interactions in our models for the first time.

These twin conditions are found most profoundly in farmland in tropical countries. And our results demonstrate that farmland in these regions has typically lost a lot of insect biodiversity, relative to areas of primary vegetation. This highlights that climate change may present a major threat to food security not only by directly impacting crops, but also through losses of pollinators and other important insects.

As climate change accelerates, the ability to grow cocoa and other crops in their current geographical ranges is already becoming more uncertain, threatening local livelihoods and reducing the availability of these crops for consumers all over the world. The insect losses our study highlights are only likely to add to this risk. Indeed, threats to food security due to the loss of insect biodiversity are already being seen in both temperate and tropical regions: for example, evidence of reduced yields due to a lack of pollinators has been reported for cherry, apple and blueberry production in the US.

In some parts of the world, farmers are resorting to hand-pollination techniques, where the flowers of crops are pollinated using a brush. Hand pollination is used for cocoa in a number of countries, including Ghana and Indonesia. These techniques can help to maintain or increase yield, but come at a high labour cost.

Reducing the declines

Our study also highlights changes that could help to reduce insect declines. Lowering the intensity of farming – for example, by using fewer chemicals and having a greater diversity of crops – mitigates some of the negative effects of habitat loss and climate change. In particular, we show that preserving natural habitat within farmed landscapes really helps insects. Where farmland in climate-stressed areas with its natural habitat largely removed shows insect reductions of 63%, on average, this number drops to as little as 7% where three-quarters of the nearby natural habitat has been preserved.

For insects living on farmland, natural habitat patches act as an alternative source of food, nesting sites and places to shelter from high temperatures. This offers hope that even while the planet continues to warm, there are options that will reduce some of the impacts on insect biodiversity.

Indeed, natural habitat availability has already been shown, at smaller scales, to have a positive impact within agricultural systems in particular. For Indonesian cocoa, increasing the amount of natural habitat has been found to boost numbers of key insects including pollinators. Our new study shows, however, that the benefits of this intervention are only found in less-intensive farming systems. This might mean reducing the level of inputs such as fertilisers and insecticides that are applied, or increasing crop diversity to ensure the benefits of nearby natural habitat can be felt.

It’s also important to note that not all species are enduring a hard time as a result of recent pressures. For example, recent work looking at UK insects has shown that while some groups have declined, others, including freshwater insects, have increased in recent years. Another study looking at worldwide insect trends also found increases in the numbers of freshwater insects. However, many of these positive trends have been reported in non-tropical regions such as the UK and Europe, where a lot has been done, for example, to improve the water quality of rivers in recent years, following past degradation.

Making a difference

The COVID-19 lockdowns prompted many of us to reconnect with the flora and fauna around us. In the UK, the warm spring weather of 2020 saw an apparent increase in the abundance of insects in the UK countryside. However, this spike was probably temporary, and something of an anomaly set against the bigger picture worldwide. 

To support more insect biodiversity in our local environments, we can plant diverse gardens to attract insects, reduce the amount of pesticides used in gardens and allotments, and reduce how often we mow our lawns. (In the UK, you could consider joining the No Mow May challenge.) However, it is not just locally that we can make a difference. Considering the choices we make as consumers could help protect insects and other creatures in the tropics. For example, buying shade-grown coffee or cocoa will ensure a lesser impact on biodiversity than crops grown in the open.

Meanwhile, governments and other public and private organisations should consider more carefully the impact their actions and policies are having on insects. This could range from the proper consideration of biodiversity within trade policies and agreements, to ensuring that products are not sourced from areas associated with high deforestation rates.

And then there’s the data issue. We are increasingly recognising the importance of insects for human health and wellbeing, and their key role in global food production systems. Safeguarding the environment to protect insects into the future will have big benefits for human societies around the world. However, none of this is possible without good data.

One important step towards a better understanding of insect biodiversity change is to bring together and assess the data that is already available. A new project of which we are part, GLiTRS (GLobal Insect Threat-Response Synthesis), is doing this by combining the work of leading experts from a range of institutions and ecological disciplines, including data analysts. The project will then assess how different insect groups are responding to certain threats. 

Understanding what is causing insect declines is key for preventing even greater losses in the future, and for safeguarding the valuable functions that insects perform. Climate change and biodiversity loss are major global crises that are two sides of the same coin. Their combined effects on food production mean the health, wellbeing and livelihoods of many people in the tropics and beyond are hanging in the balance. Insect biodiversity losses are a crucial, but as yet understudied, part of this story.

Tim Newbold is a Senior Research Fellow at the Centre for Biodiversity and Environment, UCL

Charlie Outhwaite is a Postdoctoral Researcher in Biodiversity Change, UCL

This article was previously published in The Conversation.

Plantings

Issue 11 – May 2022

Also in this issue:

The Narcissus in Art
By Clara Muller

Plants Have an “Ear” for Music
By Matthew Sedacca

Pollen Can Raise your Risk of COVID-19
Interview with Lewis Ziska

Protecting Biodiversity—and Making it Accessible—Has Paid Off for Costa Rica
By Alejandra Echeverri Ochoa and Jeffrey R. Smith

Nature Soothes and Restores: Enjoy the Practice of Forest Bathing
By Gayil Nalls