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Georgina Smith/CIAT

Science on the Pulse: Top reads from December

Compelling discussion, commentary, stories on agriculture within thriving ecosystems.

This post is part of the Science on the Pulse series - a series which highlights the latest literature on ecosystem services and resilience.

Here’s a spin on what caught our eye this month. First, we want to highlight “The Economics of Ecosystem and Biodiversity Agriculture and Food” (or TEEBAgFood) interim report released at the Global Landscapes Forum in Paris. This report provides an excellent means of assessing the sustainability of agricultural and food systems and the multitude of trade-offs that should be considered in food production systems.


River Tana watershed
CIAT and partners explore ecosystems trade-offs to benefit both the environment and improve farmer incomes and livelihoods in the Tana River Basin, Kenya.
Georgina Smith/CIAT

From an ecosystem service point of view, what I find the report really calls into question is the logic of classifying agricultural production as an ecosystems service. As a Nepali colleague at ESP commented – “The way we produce food today is an ecosystem disservice, not an ecosystem service!” It also calls to question whether we should be focusing more attention to regulating cultural services in rural landscapes. Congratulations to the TEEBAgFood authors for getting this out, and to the many CGIAR Water Land and Ecosystems colleagues whom contributed!

Climate change is on the agenda. We didn’t start the fire…

The Indonesian peat fires continue to capture headlines in Science and Nature. Susan and Bill Laurance write that peat fire emissions are likely to worsen reaching proportions of global crisis. Combined economic and environmental pressures are likely to worsen the crisis with continued drought conditions and efforts to establish a Council of Palm Oil Producing Countries to force major forest-exploiting corporations to relax their zero-deforestation pledges. We rapidly need combined forest and agricultural policies to tackle this crisis to address conservation, climate and regional health concerns. Wijedasa and colleagues in the same issue highlight the need for continued consumer pressure to tackle the problem including some of the successes of the Singapore Transboundary Haze Pollution Act.

Brazil also made the news in the pages of Science this month with an ambitious proposal to reduce emissions by 43% below 2005 levels (on par with EU targets). However, they note that the situation is worrisome in the Cerrado—the most coveted region for agribusiness expansion—where 80% of the private property can be legally deforested, particularly for soybean production. Deforestation in the Cerrado contributes to 26% of emissions from land-use change and is expected to increase because there remains 40 Mha that could be legally deforested. Additional conservation policies, such as payments for ecosystem services and protected area expansion, are unlikely to curb emissions from deforestation to the levels promised by Brazil.

What’s in it for me?

Bioversity scientist Adam Drucker teams up with others in Midler et al. to “unravel the effect of payments for ecosystem services on motivation for collective action”.  Their results, based on an existing initiative to reward Peruvian farmers conserving agricultural biodiversity, suggest that individual rewards outperform collective rewards except where there is strong social cohesion and communication between farmers is encouraged.

Thinking small to see big.

Biodiversity and ecosystem services typically conjure images of bees providing pollinator services – but its very likely that the workhorses of ecosystem services are microbes – particularly in agriculture. Colleagues in the pages of Science call for a Unified Microbiome Initiative (UMI) to “to discover and advance tools to understand and harness the capabilities of Earth's microbial ecosystems”.

The group argues that: “given that nearly every habitat and organism hosts a diverse constellation of microorganisms—its “microbiome”—such knowledge could transform our understanding of the world and launch innovations in agriculture, energy, health, the environment… By manipulating interactions at the root-soil-microbe interface, we may reduce agricultural pesticide, fertilizer, and water use, enrich marginal land and rehabilitate degraded soils.” We’ll be sure to keep an eye on this rapidly evolving domain of microbiology and how we might consider micro-biodiversity in our CGIAR work on Regenerating Degraded Agricultural Ecosystems.  

Although in another domain “Feeding the brain and nurturing the mind: Linking nutrition and the gut microbiota to brain development” presented by Goyal et al. in PNAS show the power of the microbiome. They propose that gut microbiome diversity (tens of trillions of organisms!) is a critical component of brain development.  They postulate disruption of the assembly of the gut microbiome through malnutrition during the first 2-3 years of post-natal life can lead to persistent cognitive abnormalities including the brain’s default mode network.

There is a lot that soil science might be able to learn from this growing field of the gut microbiome and its approaches by focusing on the metabolic impacts of soil degradation and restoration, to managing soil biodiversity for greater carbon storage.

Africa poised to rescue U.S. Agriculture?

This is not a situation we are accustomed to considering. However, two articles over the past couple of years suggest that US farmers may be switching to more drought tolerant millet and sorghum in the face of growing water shortages. Secondly, a more recent article in CNN explores whether African honeybees may be part of the solution to the pollinator crisis in California, Texas and Florida. These two papers suggest that we might be thinking about “assisted migration” with functional biodiversity (pollinators and drought tolerant species/varieties), similar to conservation approaches of supporting the relocation of species across fragmented landscapes. This will first require a better understanding of species traits, their pairing with agricultural environments, and the functions they provide.

The importance of maintaining connectivity, in an increasingly fragmented current and future world was nicely highlighted in a piece by Mann et al. Here’s a quote from their punch line worth mulling over: “the end of the last ice age was fatally unique because the geographic ranges of arctic mega-fauna became permanently fragmented after stable, interglacial climate engendered the spread of peatlands at the same time that rising sea level severed former dispersal routes”. We’d argue that maintaining connectivity is more important than ever as agriculture continues to dice up our landscapes. We’ll be pushing our colleagues at NatCap to help us add a connectivity model in the next iteration of MESH – see the section below on Bridges and Barriers for other applications).

Oh spare me, not this old this argument again!

A fascinating paper in Nature by Mauser and colleagues suggested that “global biomass production potentials exceed expected future demand without the need for cropland expansion”. Mauser et al. results indicate that it is feasible to meet global food security needs by improving farm management with increased cropping intensity and more annual harvests where feasible accompanied with an economically more efficient spatial allocation of crops to maximize farmers’ profit.

Although it is a valid academic exercise, it is not clear that this path will help us to solve the global challenges we currently face. For example, the focus on high-energy crops suggests that we may all be fat and sassy in 2050, but potentially severely undernourished. There is no mention of fruit, nut, and vegetable production which Chris Murray of the University of Washington suggests needs to increase by 44-68% to meet the “low risk diet” needs of today’s population, let alone the 9 billion. Mauser’s study is loosely grounded in a land-sparing framework, It would be also fascinating to repeat Mauser’s study with variable proportions of croplands set aside for conservation – i.e. 10, 20, 30% out of agriculture production for habitat, connectivity, pollination, pest control and stream buffers, or land sharing scenarios to see how the numbers change.

Last week in Paris, at the recent Global Landscapes Forum, Patrick Holden of the Sustainable Food Trust begged that we put this nonsensical land-sharing/land-sparing debate to rest – “sharing” is the only option for achieving sustainability and moving away from the notion that we can sustainably feed 9 billion, mitigate climate change, ensure access to clean water, and protect biodiversity with a land-sparing approach. I agree, let’s put that baby to bed.

Time for ecosystem services.

We’re rapidly increasing in our capacity to assess multiple ecosystem services, however, the time dimension is rarely included in such assessments. In PNAS, Renard, Rhemtulla, and Bennett provide us with one first analysis looking at the “historical dynamics of ecosystem service bundles”.  By going back to 1971 and considering nine specific ecosystem services, they demonstrate clear evidence of the dynamic nature of ecosystem service interactions and identify the processes and drivers behind changing relationships between services.

Bioversity scientist Sylvia Wood, also working with Rhemtulla, published in this month’s issue of Agriculture, Ecosystems and the Environment on “trading off ecosystem services for economic gain in shifting cultivation landscapes”. They found that enriched fallows (or orchards) in the Amazon provide equivalent levels of 5 ecosystem services as traditional fallow forests, but with reduced habitat values. The economic gains of these orchards remained relatively low however, begging the question of their capacity to transition communities out of poverty, and collective impacts on forest conservation.

Variety is the spice of life – and may enlarge safe operating space.

This paper by Carpenter et al. published in PNAS merits some mulling over. The take home message offered by the co-authors is that actions that reduce variance in the provision of an ecosystem service over the short-term increases long-term fragility increasing the risk of surpassing important ecosystem thresholds. Decreased variability drives ecosystem fragility by changing boundaries, cancelling signals of decreased resilience, and removing pressures that may build tolerance to stress.

Bridges and Barriers

The notion of “bridges and barriers”, that is, whether conservation interventions that foster connectivity for wild biodiversity, can serve as barriers for agricultural pests is an interesting example of integrated landscape management. Bouyer and colleagues from CIRAD published really cool work in PNAS for establishing the landscape friction for the tsetse fly. Friction is a measure of how difficult it is for a species to move through a landscape. The approach they present provides a useful landscape tool for informing choice on the most appropriate intervention strategies to be implemented against pest species and also be used to support conservation of endangered species.  One of our own studies in Costa Rica is also looking at “bridges and barriers” to the coffee berry borer.