Eat healthy and sustainably, don’t leave yourself behind

By Barbara Willaarts, researcher with the IIASA Water Program

On World Water Day 2019, IIASA researcher Barbara Willaarts tells us more about how our dietary choices can contribute towards reaching the UN’s Sustainable Development Goal 6: Water for all by 2030.

© Katarzyna Bialasiewicz | Dreamstime.com

The theme chosen for World Water Day 2019 is “Leaving no one behind”. As the UN emphasizes, this year is very much about reminding ourselves that there are still considerable efforts required to provide clean water, sanitation, and hygiene for all people across the globe.

While there is no question about the fact that we should push our governments and decision makers to pursue the fundamental human right of access to clean water, bringing forward the sustainable development water agenda – specifically Sustainable Development Goal (SDG) 6 : Water for all by 2030 – requires that action is taken on multiple fronts. Securing access and sanitation, is a top priority, but how we manage the water we have access to, is also fundamental.

The first key message here is that a lot of the actions that are required to overcome many of the global water challenges like water scarcity, pollution, and ecosystem degradation, actually do not require expensive government interventions. Many rely on us, on the choices that we make as citizens and consumers in our day-to-day activities. What we wear, how we eat, or what we buy and where we buy it, are daily personal decisions, and these can make a huge difference when it comes to achieving the sustainable development agenda and in particular, SDG6.

In the past years I have conducted various research projects looking into the footprints of our lifestyles, particularly in western societies. The aim behind these investigations was not only to quantify impacts to raise awareness, but also to use this information to define benchmarks for sustainable consumption.

Being Dutch, it is not strange that I have developed my professional career in the water sector, and living in Spain (the most arid country in the EU) for many years has only deepened my interest in looking into drivers of and solutions to global water scarcity. Anyone working in this field will quickly agree that exploring solutions to water scarcity problems very often implies looking at solutions related to the way we produce and consume agricultural products.

There is a bunch of interesting literature out there assessing solutions to increase the efficiency of agricultural production systems and pathways to reduce its environmental footprint. Approaching the food problem from a consumption perspective, however, is an arena that researchers only recently started to explore. This is promising because, firstly, the benefits of improving consumption patterns might outweigh those achieved through efficiency gains. Secondly, this science often conveys messages that are easy to grasp and implement, for example, eat meat only once a week, buy local, and eat five a day of vegetables and fruits. Lastly, it also empowers citizens as the main actors of the social change that is required to meet the sustainability agenda.

With that said, I would like to reflect on a recent study led by colleagues from the Polytechnic University of Madrid and the Food and Agricultural Organization, that I was involved in. The research in question is about the water and nutritional implications of shifting diets, and we used Spain as a case study. The choice of the case study was driven by the fact that Spain, like other Mediterranean countries, is often recognized and valued for its fresh, locally grown, and healthy diets. The reality is however that, while it has been so for many years, things across the Mediterranean, and particularly in Spain, have changed substantially after the 70s as a result of a number of drivers including increasing migration to cities, incorporation of more women into the labor force, work-life imbalance, and food trade openness.

According to the results of our study, the dietary shift in Spain is such that current diets resemble an inverted food pyramid, with households eating 15% more meat, beverages, and sugar products and 37% less fruits and vegetables on a daily basis than what is actually recommended by the Mediterranean dietary guidelines. The effect of this shift is that today, Spain ranks fifth in the EU of countries with the highest prevalence of obesity and overweight.

These dietary shifts have all sorts of nutritional and environmental implications. From a nutritional perspective, current diets contain 17% more kilocalories (Kcal) – meaning units of energy – than the recommended intake, as well as a 36% higher content of macro-nutrients like fats and proteins.  On the other extreme, the intake of essential micro-nutrients like vitamins and minerals has decreased sharply by 40%.

From a water perspective, the observed dietary shifts have increased the water footprint of food consumption by 34%, which is equivalent to seven times the daily per capita consumption of domestic water. An interesting finding here is that current dietary patterns are not just more water intense, but also more international, since over 40% of water “eaten” is from imported food products. This basically means that the Spanish food basket is no longer local but is increasingly being filled with foreign land, biodiversity, and water resources.

Spain is not a unique case and it is very likely that similar trends are occurring across other European and developed countries. This clearly evidences that what we eat matters a lot – to our health and to our environment. Most importantly, you and I have the capacity to make the difference. Eat healthy, eat sustainably, and don’t leave yourself behind!

Reference:

Blas A, Garrido A, Unver O, & Willaarts B (2019). A comparison of the Mediterranean diet and current food consumption patterns in Spain from a nutritional and water perspective. Science of the Total Environment 664: 1020-1029.

Note: This article gives the views of the author, and not the position of the Nexus blog, nor of the International Institute for Applied Systems Analysis.

Insights into the future of agriculture from past human climate change responses

Ancestral Puebloans

© Marcus Thomson

By Marcus Thomson, researcher, IIASA Ecosystems Services and Management Program

While living in Cairo in 2010, I witnessed first-hand the human toll of political and environmental disasters that washed over Africa at the end of the last century. Unprecedented numbers of migrants were pressing into North Africa, many pushed out of their homelands by conflict and state-failure, pulled towards safer, richer, less fragile places like Europe. Throughout Sub-Saharan Africa, climate change was driving up competition for scarce land and water, and raising pressure on farmers to maintain the quantity and quality of their crops.

It is a similar story throughout the developing world, where many farmers do without the use of expensive chemical fertilizer and pesticides, complex irrigation, or boutique seed varieties. They rely instead on traditional land management practices that developed over long periods with consistent, predictable conditions. It is difficult to predict how dryland farmers will respond to climate change; so it is challenging to plan for various social, economic, and political problems expected to develop under, or be exacerbated by, climate change. Will it spur innovation or, as has been argued for the Syrian civil war[1], set up conflict? A major stumbling block is that the dynamics of human social behavior are so difficult to model.

Instead of attempting to predict farmers’ responses to climate change by modelling human behavior, we can look to the responses to environmental changes of farmers from the past as analogues for many subsistence farmers of the future. Methods to fill in historical gaps, and reconstruct the prehistoric record, are valuable because they expand the set of observed cases of societal-scale responses to environmental change. For instance, some 2000 years ago, an expansive maize-growing cultural complex, the Ancestral Puebloans (APs), was well established in the arid American Southwest. By AD 1000, members of this AP complex produced unique and innovative material culture including the famed “Great Houses”, the largest built structures in the United States until the 19th century. However, between AD 1150 and 1350, there was a profound demographic transformation throughout the Southwest linked to climate change. We now know that many APs migrated elsewhere. As a PhD student at the University of California, Los Angeles, I wondered whether a shift to cooler, more variable conditions of the “Little Ice Age” (LIA, roughly AD 1300 to 1850) was linked to the production of their staple crop, maize.

I came to IIASA as a YSSP in 2016 to collaborate with crop modelers on this question, and our work has just been published in the journal Quaternary International.[2] I brought with me high-resolution data from a state-of-the-art climate model to drive the crop simulations, and AP site information collected by archaeologists. Because AP maize was quite different from modern corn, I worked with IIASA soil scientist Juraj Balkovič to modify the crop simulator with parameters derived from heirloom varieties still grown by indigenous peoples in the Southwest. I and IIASA economic geographer Tamás Krisztin developed a statistical technique to analyze the dynamical relationship between AP site occupation and simulated yield outcomes.

We found that for the most climate-stressed high-elevation sites, abandonments were most associated with increased year-to-year yield variability; and for the least stressed low-elevation and well-watered sites, abandonment was more likely due to endogenous stressors, such as soil degradation and population pressure. Crucially, we found that across all regions, populations peaked during periods of the most stable year-to-year crop yields, even though these were also relatively warm and dry periods. In short, we found that AP maize farmers adapted well to gradually rising temperatures and drought, during the MCA, but failed to adapt to increased climate variability after ~AD 1150, during the LIA. Because increased variability is one of the near certainties for dryland farming zones under global warming, the AP experience offers a cautionary example of the limits of low-technology adaptation to climate change, a business-as-usual direction for many sub-Saharan dryland farmers.

This is a lesson from the past that policymakers might take note of.

[1] Kelley, C. P., Mohtadi, S., Cane, M. A., Seager, R., & Kushnir, Y. (2015). Climate change in the Fertile Crescent and implications of the recent Syrian drought. Proceedings of the National Academy of Sciences, 201421533.

[2] Thomson, M. J., Balkovič, J., Krisztin, T., MacDonald, G. M. (2018). Simulated crop yield for Zea mays for Fremont Ancestral Puebloan sites in Utah between 850-1499 CE based on temperature dailies from a statistically downscaled climate model. Quaternary International. https://doi.org/10.1016/j.quaint.2018.09.031

Rice and reason: Planning for system complexity in the Indus Basin

By Alan Nicol, Strategic Program Leader at the International Water Management Institute (IWMI)

I was at the local corner store in Uganda last week and noticed the profusion of rice being sold, the origin of which was from either India or Pakistan. It is highly likely that this rice being consumed in Eastern Africa, was produced in the Indus Basin, using Indus waters, and was then processed and shipped to Africa. That is not exceptional in its own right and is, arguably, a sign of a healthy global trading system.

Nevertheless, the rice in question is likely from a system under increasing stress, one that is often simply viewed as a hydrological (i.e., basin) unit. What my trip to the corner store shows is that perhaps more than ever before a system such as the Indus is no longer confined–it extends well beyond its physical (hydrological) borders.

Not only does this rice represent embedded ‘virtual’ water (the water used to grow and refine the produce), but it also represents policy decisions, embedded labor value, and the gamut of economic agreements between distribution companies and import entities, as well as the political relationship between East Africa and South Asia. On top of that are the global prices for commodities and international market forces.

In that sense, the Indus River Basin is the epitome of a complex system in which simple, linear causality may not be a useful way for decision makers to determine what to do and how to invest in managing the system into the future. Integral to this biophysical system, are social, economic, and political systems in which elements of climate, population growth and movement, and political uncertainty make decisions hard to get right.

Like other systems, it is constantly changing and endlessly complex, representing a great deal of interconnectivity. This poses questions about stability, sustainability, and hard choices and trade-offs that need to be made, not least in terms of the social and economic cost-benefit of huge rice production and export.

An aerial view of the Indus River valley in the Karakorum mountain range of the Basin. © khlongwangchao | Shutterstock

So how do we go about planning in a system that is in such constant flux?

Coping with system complexity in the Indus is the overarching theme of the third Indus Basin Knowledge Forum (IBKF) being co-hosted this week by the International Centre for Integrated Mountain Development (ICIMOD), the International Institute for Applied Systems Analysis (IIASA), the International Water Management Institute (IWMI), and the World Bank. Titled Managing Systems Under Stress: Science for Solutions in the Indus Basin, the Forum brings together researchers and other knowledge producers to interface with knowledge users like policymakers to work together to develop the future direction for the basin, while improving the science-decision-making relationship. Participants from four riparian countries–Afghanistan, China, India, and Pakistan–as well as from international organizations that conduct interdisciplinary research on factors that impact the basin, will work through a ‘marketplace’ for ideas, funding sources, and potential applications. The aim is to narrow down a set of practical and useful activities with defined outcomes that can be tracked and traced in coming years under the auspices of future fora.

The meeting builds on the work already done and, crucially, on relations already established in this complex geopolitical space, including under the Indus Forum and the Upper Indus Basin Network. By sharing knowledge, asking tough questions, and identifying opportunities for working together, the IBKF hopes to pin down concrete commitments from both funders and policymakers, but also from researchers, to ensure high quality outputs that are of real, practical relevance to this system under stress–from within and externally.

Scenario planning

Feeding into the IBKF3, and directly preceding the forum, the Integrated Solutions for Water, Energy, and Land Project (ISWEL) will bring together policymakers and other stakeholders from the basin to explore a policy tool that looks at how best to model basin futures. This approach will help the group conceive possible futures and model the pathways leading to the best possible outcomes for the most people. This ‘policy exercise approach’ will involve six steps to identify and evaluate possible future pathways:

  1. Specifying a ‘business as usual’ pathway
  2. Setting desirable goals (for sustainability pathways)
  3. Identifying challenges and trade-offs
  4. Understanding power relations, underlying interests, and their role in nexus policy development
  5. Developing and selecting nexus solutions
  6. Identifying synergies, and
  7. Building pathways with key milestones for future investments and implementation of solutions.

The summary of this scenario development workshop and a vision for the Indus Basin will be shared as part of the IBKF3 at the end of the event, and will help the participants collectively consider what actions can be taken to ensure a prosperous, sustainable, and equitable future for those living in the basin.

The rice that helps feed parts of East Africa plays a key global role–the challenge will be ensuring that this important trading relationship is not jeopardized by a system that moves from pressure points to eventual collapse. Open science-policy and decision-making collaboration are key to making sure that this does not happen.

This blog was originally published on https://wle.cgiar.org/thrive/2018/05/29/rice-and-reason-planning-system-complexity-indus-basin.

Note: This article gives the views of the author, and not the position of the Nexus blog, nor of the International Institute for Applied Systems Analysis.

Cornelius Hirsch: Digging into foreign investment in agriculture

By Parul Tewari, IIASA Science Communication Fellow 2017

Two things are distinctly noticeable when you meet Cornelius Hirsch—a cheerful smile that rarely leaves his face and the spark in his eyes as he talks about issues close to his heart. The range is quite broad though—from politics and economics to electronic music.

Cornelius Hirsch

After finishing high school, Hirsch decided to travel and explore the world. This paid off quite well. It was during his travels, encompassing Hong Kong, New Zealand, and California, that Hirsch started taking a keen interest in economic and political systems. This sparked his curiosity and helped him decide that he wanted to take up economics for higher studies. Therefore, after completing his masters in agricultural economics, Hirsch applied for a position as a research associate at the Austrian Institute of Economic Research and enrolled in the PhD-program of the Vienna University of Economics and Business to study trade, globalization, and its impact on rural areas. Currently, he is looking at subsidies and tariffs for farmers and the agricultural sector at a global scale.

As part of the 2017 Young Scientists Summer Program at IIASA, Hirsch is digging a little deeper to analyze how foreign direct investments (FDI) in agricultural land operate. “Since 2000, the number of foreign land acquisitions have been growing—governmental or private players buy a lot of land in different countries to produce crops. I was interested in knowing why there are so many of these hotspots in the world— sub-Saharan Africa, Papua New Guinea, Indonesia—why are people investing in these areas?,” says Hirsch.

Farming in one of the large agricultural areas in Indonesia ©CIFOR I Flickr

Increased food demand from a growing world population is leading to an increased rate of investment in agriculture in regions with large stretches of fertile land. That these regions are largely rain-fed make them even more attractive for investors as they save the cost of expensive irrigation services. In fact, Hirsch argues that “the term land-grabbing is misleading. It should actually be water-grabbing as water is the foremost deciding factor—even more important than simply land abundance.”

Some researchers have found an interesting contrast between FDI in traditional sectors, such as manufacturing, and the ones in agricultural land. While investors in the former look for stable institutions and good governmental efficiency, FDI in land deals seems to target regions with less stable institutions. This positive relationship between corruption and FDI is completely counterintuitive. Hirsch says that one reason could be that “sometimes weaker institutions are easier to get through when it comes to such vast amount of lands. A lot of times these deals and contracts are oral and have no written proof—the contracts are not transparent anyway.”

For example in South Sudan, the land and soil conditions seem to be so good that investors aren’t deterred despite conflicts due to corrupt practices or inefficient government agencies.

One of the indigenous communities in Madagascar, a place which is vulnerable to land acquisitions © IamNotUnique I Flickr

One area that often goes unnoticed is the violation of land rights of indigenous communities. If a government body decides to sell land or give out production licenses to investors for leasing the land without consulting the actual community, it is only much later that the affected community finds out that their land has been given away. Left with no land and hence no source of livelihood, these communities are forced to migrate to urban areas.

A strain of concern enters his voice as Hirsch talks about the impact. “Land as big as two times the area of Ecuador has been sold off in the past—but it accounts for a tiny percentage of the global production area.” With rising incomes and greater consumption of meat, a lot of land is used to produce animal feed crops. “This is a very inefficient way of using land,” he says.

During the summer program at IIASA, Hirsch is generating data that will help him look at these deals in detail and analyze the main factors that are taken into consideration before finalizing a land deal. At the moment he is only able to give an overview of land-grabbing at the global level. With more data on the location of the deals he can look at the factors that influence these decisions in the first place such as the proximity between the two countries involved in agricultural investments and the size of their economies.

While there is always huge media coverage when a scandal about these land acquisitions comes out in the open, Hirsch seems determined to dig deeper and uncover the dynamics involved.

About the researcher
Cornelius Hirsch is a research associate at the Austrian Institute of Economics and Research (WIFO). At IIASA he is working under the supervision of Tamas Krisztin and Linda See in the Ecosystems Services and Management Program (ESM).

This article gives the views of the author, and not the position of the Nexus blog, nor of the International Institute for Applied Systems Analysis.

Disappearing Act: Bolivia’s second largest lake dries up

By Parul Tewari, IIASA Science Communication Fellow 2017

In 2016, Bolivia saw its worst drought in nearly 30 years. While the city of La Paz faced an acute water shortage with no piped water in some parts, the agricultural sector was hit the hardest. According to The Agricultural Chamber of the East, the region suffered a loss of almost 50% of total produce. Animal carcasses lay scattered in plain sight in the valleys, where they had died looking for watering holes.

Lake Poopo (Bolivia) before it dried up © David Almeida I Flickr

One of the most dramatic results of this catastrophic drought was that Lake Poopo, (pronounced po-po) Bolivia’s second largest lake was drained of every drop of water. Located at a height of approximately 1127 meters, and covering an area of 1,000 square kilometers, what remains of it now resembles a desert more than a lake. This event forced the fishing community of Uru Uru, which depended on the lake, to either migrate to other lakes or look for alternate livelihood options.

Lake Poopo is located in the central South American Altiplano, one of the largest high plateaus in the world (Bolivia’s largest lake, Titicaca, is located in the north of the region). Due to its unique topography, the highland faces extreme climatic conditions, which are responsible for difficult lives as well as widespread poverty among the people who live there.

While Titicaca is over 100 meters deep, Poopo had a depth of less than three meters. Combined with a high rate of evapotranspiration, erratic rainfall, and limited flow of water from the Desaguadero River, Poopo was in a precarious position even during the best of times. Whatever little water flowed in from the river is further depleted by intensive irrigation activities at the south of Lake Titicaca before the water makes it way down to Poopo.

Sattelite images of Lake Poopo

Changes in water levels of Lake Poopo over 30 years © U.S. Geological Survey, Associated Press

The lake’s existence had been threatened several times in the past. However, the 2016 drought was one of the most devastating ones. According to the Defense Ministry of Bolivia, early this year the lake started recovering after several days of heavy rain, restoring as much as 70% of the water. However, since the lake is a part of a very fragile ecosystem, there have been some irreversible changes to the flora and fauna in addition to the losses to the fishing communities living around the lake.

Charting a better future

Claudia Canedo, a participant of the 2017 Young Scientists Summer Program (YSSP) at IIASA, is exploring the impact of droughts and the risk on agricultural production in the light of this event, after which Bolivia declared a state of water emergency. Canedo was born and raised in the city of La Paz and experienced water shortages while growing up close to the Altiplano. This motivated her to investigate a sustainable solution for water availability in the region. With the results of her study she is hoping to ensure that such a situation doesn’t arise again in the Altiplano – that other communities directly dependent on ecosystem services, like that of Lake Poopo, do not have to lose everything because of an extreme weather event.

For a region where more than half the population is dependent on agriculture for their livelihoods, droughts serve as a major setback to the national economy. “It is not just one factor that led to the drought, though. There were different factors that contributed to the drying up of the lake and also contribute to the agricultural distress,” she says.

“The southern Altiplano lies in an arid zone and receives low precipitation due to its proximity to the Atacama Desert. Poor soil quality (high saline content and lack of nutrients) makes it unsuitable for most crops, except quinoa and potato in some areas,” adds Canedo. Residents also lack the knowledge and the monetary resources to invest in newer technology, which could possibly lead to better water management.

A woman from one of the drought affected communities in Bolivia © EU – Photo credits: EC/ECHO/Laurence Bardon I Flickr

One of the most critical factors in the recent drought was the El Nino- Southern Oscillation, the warming of the sea temperatures in the Pacific Ocean, which in turn carries the warmer oceanic winds and lowers the rate of precipitation in the highland leading to increased evapotranspiration. In 2015 and 2016, the losses due to this phenomenon were devastating for agriculture in the Altiplano, says Canedo.

In her quest to find solutions, the biggest challenge is the lack of recorded data from local weather stations for the past years. Although satellite data is available, it is too generic in nature to do a local analysis. Therefore combining ground and satellite data could enhance the present knowledge and provide consistent results of the climate and vegetation variability. If done successfully, Canedo hopes to identify a correlation between precipitation and vegetation. With this information, she can improve climate forecasting that could help the local people adapt to droughts powerful enough to turn their lives upside down.

With weather forecasts and early warning systems for extreme weather events like droughts, farmers would know what to expect and would be able to plant resilient varieties of crops. This might not earn them the same profits as in a normal year, but would not result in a failed crop. Claudia aims to come up with a drought index useful for drought monitoring and early warning, which will integrate short-term and long-term meteorological predictions.

Perhaps, in the future, with this newfound knowledge, the price for extreme weather events won’t be paid in terms of lost ecosystems like that of Lake Poopo, robbing people of their lives and livelihoods.

About the Researcher

Claudia Canedo is a participant in the 2017 IIASA YSSP. She is pursuing a doctoral program in water resources engineering at Lund University, Sweden. She is interested in studying the hydrological and climatological conditions over small basins in the South American highlands. The aim of her research is to define water resources availability and find strategies for sustainable water management in the semi-arid region.

This article gives the views of the author, and not the position of the Nexus blog, nor of the International Institute for Applied Systems Analysis.

 

 

 

Interview: Are we accidentally genetically engineering the world’s fish?

Mikko Heino is a researcher in the IIASA Evolution and Ecology Program who over the past 18 years has worked on the problem of fisheries-induced evolution, showing that selective harvesting of bigger fish can lead to evolutionary changes towards smaller and faster-maturing fish populations. A new review by Heino and colleagues explores the accumulated evidence on the topic, and future directions for new research.

What is fisheries-induced evolution?
In agriculture we are used to thinking about selective breeding: farmers select the best animals or plants to breed, in order to improve their fitness or select for certain traits in the next generation. They are intentionally trying to improve the stock used for breeding. In fisheries, the opposite happens: fishermen usually try to catch the fish that are more valuable—bigger and heavier. Consequently, those valuable kinds of fish are less likely to reproduce and contribute to the next generations.

It’s not intentional, and maybe because we don’t see the fish that are left behind, people are not used to thinking of this as selective breeding—and they may not realize that in the long term it could harm the productivity of the whole fishery.

Atlantic cod are among the best-studied fish populations and most important fisheries worldwide © davidyoung11111 | Dollar Photo Club

Atlantic cod are among the best-studied and most important fisheries worldwide (Credit: © davidyoung11111 | Dollar Photo Club)

What kinds of evolutionary changes do your research show that you would see from fisheries?
Most of our data comes from fisheries institutions. We have a lot of data on maturation—the age at which fish start to reproduce. Studies show that heavily harvested fish populations may mature faster and start reproducing earlier. There’s also some data on growth, showing that fisheries pressures can lead to slower growth rates, with fish staying smaller.

In recent years, experimental studies have shown that fishing is also selective with respect to behavioral traits. Some fish are bolder than others and those bolder fish may be more likely to be captured by gillnets or traps, because bold fish are more explorative, they like to investigate things, and by doing so they may end up in a trap. But at the same time, they may be better in escaping fishing gear like a trawl.

Why is it important that we understand what’s happening with fisheries-induced evolution?
At one level it’s important because changes in these kind of traits will affect the productivity of fish stocks—and based on our current knowledge, these changes are often negative, leading to lower productivity. However, some parts of these changes may be positive in the short term, because they may enable fish stocks to tolerate higher levels of fishing without collapsing. Yet in the long term, we would expect fisheries-induced evolution to lead to reduced productivity, and lower yields. And that’s quite worrying, because fish are an important part of the human diet, especially in many coastal developing countries.

What are the major questions remaining in this research?
One big question arises from the fact that evolution of course implies genetic change. In fisheries, we are observing this evolution at the level of phenotypes—visible, directly measurable characteristics. To be sure that we really observe evolutionary change, we also need to understand the genetic basis for these kinds of changes.

How can you do that?
There are ongoing projects trying to look at it the genetics of fisheries-induced evolution. But it’s a lot more difficult than it sounds because life-history traits and behavioral traits are affected by many genes. It’s not like there’s one gene for early maturation. There are probably tens if not hundreds of genes that have some influence on maturation. And that means that at the level of a single gene we may not see very much change at all. And trying to identify those changes and separate those from random drift, and from changes caused by other factors, is actually quite difficult.

Sequencing genomes is easy nowadays, but finding a signal in the resultant large amounts of data is not simple. If you have more data, you also get more false positives. Basically, either you need to sequence a lot of individuals, so you can separate the different signatures. The other possibility is to try to analyze data from selection experiments, because in an experiment you can try to exaggerate the changes. That’s maybe the most fruitful avenue in the short term.

Evidence for fisheries-induced evolution: research shows fisheries-induced evolution in many fish populations, including marine and freshwater species. (Credit: Heino & Dieckmann, 2015)

Evidence for fisheries-induced evolution: research shows fisheries-induced evolution in many fish populations, including marine and freshwater species. (Credit: Heino & Dieckmann, 2015)

What can fisheries managers do to avoid unintended evolutionary changes?
We’re currently exploring that question. We more or less know that it’s not possible to avoid all types of evolutionary responses. But we can still try to minimize harmful changes, by fishing in a way that does not cause much negative change in productivity.

Of course, fisheries-induced evolution will not be the only thing we care about when managing fish stocks. It has to be seen together with other objectives. Yet the simplest way of reducing unwanted evolutionary changes is to keep fishing pressure at moderate levels. That’s the single easiest and most certain way of reducing unwanted evolution, and that’s in agreement with what scientists recommend from other perspectives too.

What are the dangers of failing to account for fisheries-induced evolution?
The danger is that it’s much easier to cause these changes than to reverse them—on practical time scales, these changes are more or less irreversible. So whatever changes we cause, will be around for many generations to come. That’s a reason to be precautionary. We don’t have absolute certainty that this is happening, but there’s a large body of research showing that it is quite likely to happen, and since if it’s happening it’s more or less irreversible, then we should avoiding it even before we have full scientific certainty.

There is quite a similarity between climate change and fisheries-induced evolution. Both processes happen on long timescales—at the level of a few years, the change is not much. But it is a change that will accumulate, and if you let that happen for longer periods, you end up having very significant changes. So it’s easy and attractive to ignore it in the short term, but that’s a dangerous position in the long term.

Reference
Heino M, Pauli BD, Dieckmann U (2015). Fisheries-induced evolution. Annual Reviews in Ecological Systems. 46:461-480. doi: 10.1146/annurev-ecolsys-112414-054339

Note: This article gives the views of the interviewee, and not the position of the Nexus blog, nor of the International Institute for Applied Systems Analysis.