Wei Zhang

• Doctor of Philosophy
• Research Associate at International Food Policy Research Institute

Reducing pesticide use and restoring biodiversity are among the most pressing environmental challenges. Enhancing natural pest control ecosystem services through the integration of non-crop habitats (NCH) offers promising potential, creating a positive feedback loop by harnessing insect biodiversity to reduce pesticide reliance. Policy support is n...

Understanding and quantifying above-ground carbon stock is critical for assessing the impact of land use choices on carbon emissions which can inform conservation and management strategies to protect and increase carbon stocks. This study introduces a novel methodology for evaluating above-ground carbon storage and sequestration in the Thoria water...

Ecosystem functions such as biological pest control are mediated by the richness and abundance of service providers i.e., biological control agents (BCAs), relative contributions of individual taxa and community structure. This is especially relevant in the native range of agricultural herbivores, where a speciose community of co- evolved BCAs can...

Human society is anchored in the global agroecosystem. For millennia, this system has provided humans with copious supplies of nutrient-rich food. Yet, through chemical intensification and simplification, vast shares of present-day farmland derive insufficient benefits from biodiversity and prove highly vulnerable to biotic stressors. Here, we argu...

Since 2016, the fall armyworm (FAW) Spodoptera frugiperda has spread over extensive areas of the tropics and subtropics, imperiling food security, economic progress and the livelihoods of millions of cereal farmers. Although FAW has received long-standing scientific attention in its home range in the Americas, chemical inputs feature prominently in...

Groundwater management is highly complex, with many users sharing the same resource often with limited understanding of their interconnectedness. Behavioral experiments (games) that simulate real-life common-pool resource use have shown promise as an experiential learning tool for improving resource governance. This study pilots an experiential lea...

Integrated landscape approaches (ILA) aim to reconcile multiple, often competing, interests across agriculture, nature conservation, and other land uses. Recognized ILA design principles provide guidance for implementation, yet application remains challenging, and a strong performance evidence-base is yet to be formed. Through a critical literature...

The goal of this study is to assess the potential of game-based experiential learning in raising awareness and stimulating discussions about groundwater resource systems, the social dilemma in groundwater management, and the need for institutional arrangements (rules) governing this shared resource, as well as whether such awareness and community d...

Freshwater resources (FWRs) are under enormous stress due to human activities and climate change. Given the centrality of local communities in managing natural resources, community-based conservation (CBC) for FWRs (fCBC) offers a mechanism for addressing these challenges. A framework informing fCBC that incorporates unique features of FWRs (such a...

Agri‐environmental schemes (AESs) are increasingly implemented to promote the adoption of environmentally friendly practices by farmers. We use a systematic review to explore the role of behavioural factors and opportunity costs in farmers' decisions to participate in AESs in Australia, Europe and North America. Behavioural factors influence how fa...

As resource users interact and impose externalities onto each other, institutions are needed to coordinate resource use, create trust, and provide incentives for sustainable management. Coordinated collective action can play a key role in enabling communities to manage natural resource commons more sustainably. But when such collective action is no...

Paying resource users to preserve features of their environment could in theory better align production and conservation goals. We show, however, that across a range of conservation dilemmas, they might not. We conduct a synthesis of dynamic games experiments built around collective action dilemmas in conservation, played across Europe, Africa, and...

Commons provide many ecosystem services that support the livelihoods of billions around the world. However, their contribution to people and the economy are rarely estimated in economic terms. Here, we estimate the economic contribution of the land-based commons in India, which cover 66.5 million hectares. We conducted a systematic literature revie...

Framed field experiments (experimental games) are widely used to assess factors affecting cooperation in management of the commons. However, there is relatively little attention to how details of the games affect experimental results. This paper presents qualitative and quantitative results from a framed field experiment in which participants make...

Excess agricultural nitrogen, mainly from manure and chemical fertilizers, is a primary source of nutrient pollution and presents serious environmental threats to natural ecosystems and human health. Improvements in nitrogen-use efficiency in crop production are critical for addressing the triple challenge of food insecurity, environmental degradat...

The ongoing COVID-19 pandemic has spotlighted the intricate connections between human and planetary health. Given that pesticide-centered crop protection degrades ecological resilience and (in-)directly harms human health, the adoption of ecologically sound, biodiversity-driven alternatives is imperative. In this Synthesis paper, we illuminate how...

Integrated landscape approaches (ILA) aim to reconcile multiple, often competing, interests across agriculture, nature conservation, and other land uses. Recognized ILA design principles provide guidance for their implementation, yet application remains challenging, and a strong performance evidence-base is yet to be formed. A comprehensive literat...

There is resurging interest in community-based natural resource management (CBNRM) as an approach for achieving global biodiversity conservation goals. Yet, CBNRM remains dominated by men, elevating the importance of designing programs that give voice and agency to women. Arguments for increasing gender balance within CBNRM often assume women have...

Nepal has a long history of irrigation, including government and farmer-managed irrigation systems that are labor- and skill-intensive. Widespread male migration has important effects on Nepalese society. How institutions such as Water Users’ Associations (WUAs) respond and adapt, is therefore critical to the understanding of rural transformation a...

Pesticide-centred crop protection is highly carbon-intensive, with product synthesis, distribution and field application generating up to 136.6 MtCO2 equivalent per year. Carbon financing offers an opportunity to bring more natural and sustainable alternatives to scale.

India is globally the largest groundwater user and simultaneously among the world’s most water stressed countries. Almost two thirds of the water requirement for irrigation and 85% of domestic water use depend on groundwater. The growing competition over water resources can only be addressed by systemic changes towards sustainable water management....

In this post, IASC members Thomas Falk and Ilkhom Soliev and their colleagues share insights and reflections on their experiences from international development interventions in India. The focus is on better understanding the role of behavioral change for improved water governance and lessons for developing intervention strategies that can create d...

Genetically‐modified crops expressing Bacillus thuringiensis (Bt) proteins have been widely cultivated, permitting an effective non‐chemical control of major agricultural pests. While their establishment can enable an area‐wide suppression of polyphagous herbivores, no information is available on the impact of Bt crop abandonment in entire landscap...

This symposium will discuss the innovative use of experimental games from behavioral economics as a tool for not only learning about collective action in natural resource management, but also as an intervention to trigger collective behavioral change. The session draws from collaboration among CGIAR centers (IFPRI and ICRISAT), an Indian NGO (Found...

Urbanization is a pressing challenge for earth’s humans because it is changing not only natural environments, but also agricultural lands. Yet, the consequences of cropland loss on pest insect populations that largely depend on these habitats remain largely unclear. We used a 17-year data set to investigate the dynamics of three moth pest species (...

The intensification of crop production has been identified as one of the major drivers of environmental degradation. While significant advances could still be made with more widespread adoption of sustainable intensification technologies that address the agronomic efficiency of nitrogen fertilizers, the dynamic use of agricultural land across seaso...

Healthy soils play a critical role in supporting agricultural productivity, climate change mitigation and resilience, and a range of ecosystem services. Degraded and poorly responsive soils cover large areas of Africa and represent the majority of poor farmers’ fields in certain regions. While many technical options for soil improvement or restorat...

Land tenure security is increasingly recognized as a foundational element for advancing global sustainable development agendas, but questions remain about how it affects human well-being and environmental outcomes. We identify 117 studies that aimed to estimate the causal effect of land tenure security interventions on these outcomes. Approximately...

Agricultural statistics on small farms are critical for informing sustainable development policies, but often suffer from selection bias and are time consuming and costly to collect. Less burdensome and reliable methods are needed. We report on a scalable method using a respondent's knowledge about their land, high resolution imagery, and tablet de...

This chapter identifies core principles of ecology and environmental science applicable to the nexus and discusses the tightly coupled socio-ecological systems that establish ecosystems services (ES) within the nexus. The chapter begins by outlining key ecological principles and their interdependencies, demonstrating how ecosystem services are prov...

Sustainable land management is at the heart of some of the most intractable challenges facing humanity in the 21st century. It is critical for tackling biodiversity loss, land degradation, climate change and the decline of ecosystem services. It underpins food production, livelihoods, dietary health, social equity, climate change adaptation, and ma...

Human land use threatens global biodiversity and compromises multiple ecosystem functions critical to food production. Whether crop yield–related ecosystem services can be maintained by a few dominant species or rely on high richness remains unclear. Using a global database from 89 studies (with 1475 locations), we partition the relative importance...

Human land use threatens global biodiversity and compromises multiple ecosystem functions critical to food production. Whether crop yield–related ecosystem services can be maintained by a few dominant species or rely on high richness remains unclear. Using a global database from 89 studies (with 1475 locations), we partition the relative importance...

Although health, development, and environment challenges are interconnected, evidence remains fractured across sectors due to methodological and conceptual differences in research and practice. Aligned methods are needed to support Sustainable Development Goal advances and similar agendas. The Bridge Collaborative, an emergent research-practice col...

Inadequacies of the current agriculture and food systems are recognised globally in the form of damages to environment and human health. In addition, the prevailing economic and policy systems do not reflect these damages in its accounting systems and standards. These shortcomings lead to perverse and pervasive outcomes for society at large. Our pr...

Despite decades of study, conservation biocontrol via manipulation of landscape elements has not become a mainstream strategy for pest control. Meanwhile, conservation groups and governments rarely consider the impacts of land management on pest control, and growers can even fear that conservation biocontrol strategies may exacerbate pest problems....

Although health, development, and environment challenges are interconnected, evidence remains fractured across sectors due to methodological and conceptual differences in research and practice. Aligned methods are needed to support Sustainable Development Goal advances and similar agendas. The Bridge Collaborative, an emergent research-practice col...

Although health, development, and environment challenges are interconnected, evidence remains fractured across sectors due to methodological and conceptual differences in research and practice. Aligned methods are needed to support Sustainable Development Goal advances and similar agendas. The Bridge Collaborative, an emergent research-practice col...

As resource users interact and impose externalities onto each other, institutions are needed to coordinate resource use and create trust and incentives for sustainable management. Collective action can play a key role in enabling changes in communities required for sustainably managing natural resources. But when such collective action is not prese...

Chapter 2 makes the case for using systems thinking as a guiding perspective for TEEBAgriFood’s development of a comprehensive Evaluation Framework for the eco-agri-food system. Many dimensions of the eco-agri-food system create complex analytical and policy challenges. Systems thinking allows better understanding and forecasting of the outcomes of...

Human land use threatens global biodiversity and compromises multiple ecosystem functions critical to food production. Whether crop yield-related ecosystem services can be maintained by few abundant species or rely on high richness remains unclear. Using a global database from 89 crop systems, we partition the relative importance of abundance and s...

In an increasingly globalized world, invasive species cause major human, financial, and environmental costs. A cosmopolitan pest of great concern is the cassava mealybug Phenacoccus manihoti (Hemiptera: Pseudococcidae), which invaded Asia in 2008. Following its arrival, P. manihoti inflicted measurable yield losses and a 27% drop in aggregate cassa...

Significance Decades of research have fostered the now-prevalent assumption that noncrop habitat facilitates better pest suppression by providing shelter and food resources to the predators and parasitoids of crop pests. Based on our analysis of the largest pest-control database of its kind, noncrop habitat surrounding farm fields does affect multi...

The idea that noncrop habitat enhances pest control and represents a win–win opportunity to conserve biodiversity and bolster yields has emerged as an agroecological paradigm. However, while noncrop habitat in landscapes surrounding farms sometimes benefits pest predators, natural enemy responses remain heterogeneous across studies and effects on p...

Significance Changes in land use, climate, and agricultural technologies affect pest severity and management. We analyzed long-term longitudinal data (1991–2015) on three major cotton pests for 51 Chinese counties. Bacillus thuringiensis (Bt) insect-resistant cotton had pervasive effects on the whole pest complex and its management. Adoption result...

Chapter 2 makes the case for using systems thinking as a guiding perspective for TEEBAgriFood’s development of a comprehensive Evaluation Framework for the eco-agri-food system. Many dimensions of the eco-agri-food system create complex analytical and policy challenges. Systems thinking allows better understanding and forecasting the outcomes of po...

Our goals are bold and ambitious: to contribute a framework approach for better understanding and managing the impacts and externalities of agriculture and food value chains, and to incite a global network of scholars and decision-makers dedicated to disclosing and valuing those impacts. Without a doubt, the complexity is daunting as we embrace, ho...

Little empirical evidence on the economic value of biological control of pests at farm level is available to improve economic decision-making by farmers and policy makers. Using insect sampling and household survey in an integrated bio-economic analysis framework, this paper studies farmers' crop management practices in cotton in the North China Pl...

Insect pests are a major cause of crop yield losses around the world and pest management plays a critical role in providing food security and farming income. This study links Nigerian farmers’ perceptions of pest severity to the landscape, agronomic, biophysical, and socio-economic context in which agricultural production takes place. A farm househ...

Background Insect pest problems are among the main causes of crop yield losses in global agriculture. Insecticides protect households from food-security and income shocks, but can induce human health and environmental risks. Semi-subsistence farm households (SSFHs), which farm for both consumption and market, make decisions about crop management an...

The TEEBAgriFood ‘Scientific and Economic Foundations’ report addresses the core theoretical issues and controversies underpinning the evaluation of the nexus between the agri-food sector, biodiversity and ecosystem services and externalities including human health impacts from agriculture on a global scale. It argues the need for a ‘systems thinki...

Achieving well-being for all, while protecting the environment, is one of the most pressing global challenges of our time, and a central idea in the UN Sustainable Development Goals (SDGs). We believe that integrating ecosystem services, the benefits nature provides to people, into strategies for meeting the SDGs can help achieve this. Many develop...

For the ecosystem service (ES) paradigm to be relevant to policy and decision-making, it is important to integrate local residents' awareness and perceptions of ES into ES assessment. Using data collected from 102 villages in Nigeria, we assessed communities' awareness and perceptions of a broad range of ES in relation to land use types. We also ex...

Sustainable Development Goals offer an opportunity to improve human well-being while conserving natural resources. Ecosystem services highlight human well-being benefits ecosystems, including agricultural ecosystems, provides. Whereas agricultural systems produce the majority of our food, they drive significant environmental degradation. This tensi...

The contribution of synthetic pesticides to closing yield gaps around the world is undeniable; however, their use is also a classic double-edged sword. Beyond the well-recognized social costs (e.g., pollution to soil and water, and health effects both on consumers and other species) there are also private costs on farmers beyond the direct costs of...

Ecologists and farmers often have contrasting perceptions about the value of natural habitat in agricultural production landscapes, which so far has been little acknowledged in ecology and conservation. Ecologists and conservationists often appreciate the contribution of natural habitat to biodiversity and potential ecosystem services such as biolo...

Shifting agricultural land management to one that promotes the use of biological control alongside insecticide spray, requires two key elements: 1) habitat for natural enemies provided by non-crop area within the agricultural landscape, and 2) judicious use of insecticides by farmers. However, barriers to adoption may include low levels of knowledg...

In this study, we focus on water quality as a vehicle to illustrate the role that the water, energy, and food (WEF) Nexus perspective may have in promoting ecosystem services in agriculture. The mediation of water quality by terrestrial systems is a key ecosystem service for a range of actors (municipalities, fishers, industries, and energy provide...

Nepal was ranked as one of the most climate vulnerable country in the world and a better understanding of vegetation patterns and their transformations is critically needed for environmental studies. Studies have shown that monitoring land use and land cover changes with conventional ground survey methods are time consuming and labor intensive. Rem...

The overall objectives of the Challenge Program on Water and Food (CPWF) Mekong Project 2, Assessing the Value of Water, are to assess the value of the various uses of water and to estimate costs and benefits associated with different water management strategies. We quantitatively assessed the value of water resources and water bodies for local liv...

This research has been undertaken to improve our understanding of stakeholders’ knowledge and perception about ecosystem services (ES), which provides a valuable means of gaining insight into the opportunities and constraints that face ES management in a multiuser landscape. Land use preferences are influenced by a variety of motives, attitudes, an...

Sustainable production of agricultural commodities and growth of international trade in these goods are challenged as never before by supply-side constraints (such as climate change, water and land scarcity, and environmental degradation) and by demand-side dynamics (volatility in food and energy markets, the strengthening food-energy linkage, popu...

By their direct effects on private profitability, invasive agricultural pests create special incentives for management that set them apart from other categories of invasive species. One attractive nonchemical management approach for agricultural pests relies upon biological control by natural enemies. By improving the habitat of natural enemies of...

This paper examines the changes in China's potato production, consumption and trade, presents an analysis of urban consumer demand for potatoes, sweet potatoes and starch products, and discusses the trends of China's potato market and potential global impacts. The time-series data suggest that Chinese consumers have significantly increased their av...

The control of pests by their natural enemies represents an important regulating ecosystem service that helps maintain the stability of crop ecosystems. These services, however, are often ignored in pest management decision making. In addition, the use of broad-spectrum insecticides can damage the populations of natural enemies, reducing the cost-e...

Agricultural ecosystems are actively managed by humans to optimize the provision of food, fiber, and fuel. These ecosystem services from agriculture, classified as provisioning services by the recent Millennium Ecosystem Assessment, depend in turn upon a web of supporting and regulating services as inputs to production (e.g., soil fertility and pol...

The paper discusses methods to compensate for the costs incurred in the supply of forest ecological services (FES), i.e. government dominated and market-based instruments as well as progress made so far in China. Factors which constrain the supply of these services and potential policy improvements are presented.

The control of crop pests by their natural enemies represents an important ecosystem service that maintains the stability of agricultural systems and has the potential to mitigate pest control costs. Recently, there has been growing interest in enhancing natural control services via habitat management that provides resources for adult natural enemi...

The control of pests by their natural enemies represents an important ecosystem service that maintains the stability of agroecosystems and has the potential to mitigate pest control costs both to private producers and to society. Extending the “"economic threshold”" concept, this paper proposes an "“ecological economic threshold”" for pesticide use...

The Earth's ecosystems provide myriad goods and services that are essential to human wellbeing. This paper offers a typology of ecosystem services that emphasizes the means by which humans experience the service rendered. The typology distinguishes between services that are directly experienced, and those that are indirect. The paper offers an illu...

This paper uses household data to assess the near-term impact of the program on incomes and activity choices of rural households in areas where the sandstorm control program (Beijing and Tianjin Sandstorm Source Control Program) was implemented. Central to our analysis is a unique panel survey conducted by the State Forestry Administration covering...

While China has been the world’s largest potato producer since 1993 and accounted for more than 80% of the increase in global potato production from 1990 to 2002, few studies have analyzed the remarkable growth in China’s potato industry and its potential impacts on the global market. This paper reviews the development and growth of China’s potato...

We analyze how choosing to use a particular type of instrument for agri-environmental payments, when these payments are constrained by the regulatory authority's budget, implies an underlying targeting criterion with respect to costs, benefits, participation, and income, and the tradeoffs among these targeting criteria. The results provide insight...

We develop a watershed-based model of green payments to examine how payments applied to different environmental performance measures compare on the basis of economic efficiency, equity, and environmental outcomes. We also explore how targeting in the specification of water quality goals (e.g., TMDLs) affects program performance.

Detailed data from 3,500 urban Chinese households are used to estimate demand elasticities and the impacts of regional and demographic variables for 17 food products through a two-stage budgeting procedure with complete demand systems. Results suggest that China's food consumption patterns will continue to shift from grains to high value food produ...