Abstract

Wildlife trade represents a major threat to endangered-species populations, especially in Southeast Asia, where trade continues at high levels despite increased efforts to control illegal activities. To identify management strategies that better mitigate the threat of this trade, research must address knowledge gaps about the complexity of established trade networks. This requires a comprehensive and interdisciplinary approach that integrates biological, anthropological, socioeconomic, and other kinds of data and involves multiple stakeholders across sectors. We present here an interdisciplinary research framework for developing such an approach. Our integrative framework, based on the social–ecological systems framework by Ostrom, can be used to explore and untangle complex wildlife trade dynamics across scales and test hypotheses derived from different disciplines to provide robust recommendations for trade management. We also discuss the need for developing databases for trade-targeted species and outline steps to build and strengthen technical and interdisciplinary capacity to support the integrative framework.

Overexploitation of wildlife to supply domestic and international trade is a global threat to biodiversity conservation goals. In particular, it has been recognized as the single largest threat to biodiversity in many Southeast Asian countries, where increasing wealth and demand for wildlife products correspond with low levels of enforcement (TRAFFIC 2008, Nijman 2010, Bennett 2011).

A large volume of wildlife is traded internationally: Each year, consumers in China, Europe, Japan, and the United States purchase billions of dollars’ worth of wildlife products from Southeast Asia (Nijman 2010). However, wildlife is also traded locally or nationally, and hunting for subsistence and traditional medicines are long-established traditions in Southeast Asia and also provide sources of income (e.g., Nekaris et al. 2010). Reductionist management of wildlife trade impedes not only goals related to environmental sustainability but also goals related to health, poverty, and hunger (TRAFFIC 2008). On the other hand, wildlife trade has significant negative implications and is known to synergize with other threats to biodiversity: Hunting and trade increase as access to forests increases through other mining or extraction efforts (e.g., Suarez et al. 2009), and zoonotic viruses are often associated with illegally imported wildlife products (Greatorex et al. 2016). Wildlife trade has also been connected with conflict and national-security issues (Douglas and Alie 2014).

Despite increased media attention to the problem, collaborative actions on the ground (e.g., the establishment of the ASEAN Wildlife Enforcement Network in 2004), and international commitments to tackle illegal wildlife trade (e.g., the London Declaration and the Kasane and Hanoi Statements), wildlife trafficking continues at high levels (Hanoi Statement 2016, UNODC 2016). Many researchers and officials agree that existing regulatory top-down or “command and control” policies are failing in this region and that changes are necessary to work toward sustainable resource use (CITES Vietnam 2008, TRAFFIC 2008). Bennett (2011) has argued that regulatory-based interventions remain the best approach because the greatest driver of trade is wildlife demand from wealthy consumers in East Asia; in other words, the major problem is not the type of intervention but rather the gaps in capacity and resources to enforce existing regulations. However, the ubiquity of the trade makes it impractical to govern using regulatory-based interventions alone (CITES Vietnam 2008, TRAFFIC 2008); to work more effectively toward sustainability, research must assess how feasible other nonregulatory incentives and interventions might be, including market-based instruments (Jepson and Ladle 2009), which some argue may have a greater chance of being equitable and effective. However, bold supply-side strategies, including regulated trade, ranching, and wildlife farming, remain hotly debated regarding their application both in Southeast Asia (Drury 2009, Brooks et al. 2010) and at a global scale (Phelps et al. 2014).

Behind each of these arguments are assumptions about the specific set of drivers of wildlife trade in Southeast Asia. In Africa and in the Neotropics, several studies have shown how wild-meat overexploitation is driven by poverty (e.g., Brashares et al. 2011, Wittemyer 2011), a lack of alternatives to wild protein (Foerster et al. 2011), conflicts and displacement (e.g., Wittemyer 2011), and the implementation and choice of enforcement measures and policies (e.g., Nyaki et al. 2014). This is not to say that the drivers of overexploitation in these regions have been completely clarified; recent work highlights how assumptions and limited contexts regarding definitions of poverty have restricted researchers’ understandings of the motivations for illegal hunting (Duffy et al. 2016).

To avoid the development of management efforts and intervention measures in Southeast Asia on assumptions based on thin evidence (Nadal and Aguayo 2014), several knowledge gaps should be addressed, especially those characterizing the highly variable and complex wildlife trade chains and socioeconomic drivers of trade (TRAFFIC 2008, Lee et al. 2014). In part, the complexity of wildlife trade in Southeast Asia stems from traditional uses and cultural values relating to wildlife and wildlife products (Donovan 2004). For example, some studies indicate that wealth and social status appear to be stronger drivers of wildlife trade in Southeast Asia than poverty, with urban consumers driving demand for wildlife products more than local subsistence in some cases (e.g., Drury 2011, Sandalj et al. 2016). However, other studies show that most wildlife is still traded locally in rural regions (e.g., Nijman 2010), meaning that further complexity may not be addressed by research that focuses solely on urban consumers. There are diverse actors with multiple cultural backgrounds along trade chains in Southeast Asia, and their actions are likely shaped by factors that vary from site to site, including financial gain, social esteem, cultural identity, and customs, among others (Nekaris et al. 2010, MacMillan and Nguyen 2014). Thus, different policy incentives and interventions may be effective at different points along the trade chain and in different locales, and research aimed at informing wildlife trade management should take into account the possibility of spatial and cultural heterogeneity in potential trade drivers at multiple scales.

We argue here that interdisciplinary research approaches that integrate socioeconomic, anthropological, psychological, governance, and biological data across multiple scales are necessary to understand the characteristics of wildlife trade dynamics and effects. Others have made similar arguments about how to improve research approaches for studying the links between poverty and illegal wildlife hunting (Duffy et al. 2016) and for studying “conservation crime” more broadly (Gibbs et al. 2010, Gore 2011). These authors note the importance of studying the structural contexts of hunting holistically, questioning assumptions about key variables and concepts, and capturing historical social, economic, and political contexts (Duffy et al. 2016). The need for interdisciplinary, holistic research approaches is of particular importance given the complex cultural, political, economic, and social contexts of Southeast Asia (McElwee 2004). However, what is needed to operationalize this idea?

Recent papers have articulated the utility of a social–ecological systems framework to study the sustainability of hunting for meat at local-site scales (van Vliet et al. 2015). Here, we describe a social–ecological systems framework to design an interdisciplinary research approach to study the illicit wildlife trade regionally and across scales in Southeast Asia. A common analytical framework that can be applied and understood across disciplines is especially necessary in cases such as the Southeast Asian wildlife trade, in which knowledge and theories from different disciplines are required to understand dynamic trade systems. The framework we present here is designed to guide the holistic study of complex wildlife trade systems, including to explore variables, question assumptions, and design interdisciplinary research questions. We focus on Southeast Asia because (a) there is an established need to fill knowledge gaps about wildlife trade in this region and (b) this region exhibits the complex cross-scale dynamics that can illustrate why an interdisciplinary research approach is so crucial to guide research on wildlife trade. However, our framework is flexible enough to be applied in other regions as well.

We discuss the steps taken and planned toward developing an interdisciplinary analysis of the pattern, scale, and drivers of trade in key targeted species in Indochina and Vietnam, a hotspot for the Southeast Asian trade network, as examples of how to implement the framework. We highlight examples of cases in which researchers might draw the wrong conclusions without a framework or rigorous integration of methods and data from different disciplines, which would lead to the misdirection of wildlife trade management efforts. We also argue for building and strengthening technical and interdisciplinary capacity to implement the approach, including the enlistment of DNA barcoding and the integration of social-science approaches.

An interdisciplinary research framework

The dynamic complexity of wildlife trade in Southeast Asia highlights the need for an interdisciplinary research framework to guide academic study of the trade and inform management decisions. An ideal framework would enable systems-level conceptualizations, or systems thinking, to identify and analyze the links among complex system elements. Emphasizing interrelationships, feedback loops, nonlinearities, and time delays, among other systems principles, promotes iterative analyses of a system's dynamic connections and interactions toward a better understanding of the whole system, thus informing an understanding of its components (Sterling et al. 2010).

The need for dynamic models and frameworks to understand complex systems has been established (Costanza et al. 1993), as has the need to integrate knowledge and theories across disciplines for effective biodiversity management (Watzold et al. 2006). Elinor Ostrom's social–ecological systems (SES) framework, which organizes multiple diverse variables across scales, represented a leap forward toward an interdisciplinary framework for empirical studies (Ostrom 2009). The SES framework enables the formal exploration of dynamic, nonlinear links and interactions among variables across scales to better understand system outcomes. Being theory neutral, a SES framework can also facilitate the exploration of variables that might be derived theoretically from different disciplines and of how assessments based only on biological or social data alone may lead to divergent interpretations of the system (Schlüter et al. 2014, Leslie et al. 2015).

Our interdisciplinary conceptual-framework (figure 1) groups variables derived from different disciplines within system components, or first-tier variables, as in Ostrom's SES framework (McGinnis and Ostrom 2014, Ostrom 2009). Second-tier variables or attributes facilitate analysis of wildlife trade in Southeast Asia. To characterize resource units and resource systems, variables stem from biological data and models at varying scales. This includes, for example, the genetic and morphological diversity as well as the population status and distribution of resource units (figure 1). Anthropological, psychological, governance, and economic data and models inform our understanding of the behavior and decisions of actors, as well as the nature of relevant governance systems. Variables could include, for example, the economic and cultural values actors place on traded species, the social networks of actors (in different hierarchical groupings, as has been noted by McGinnis and Ostrom 2014), access to education and technology, laws and knowledge of laws, and infrastructure related to enforcement and transportation. We describe the analysis of process relationships, interactions, and outcomes to operationalize the framework into mathematical model(s) in the next section. Related ecosystems and additional social, economic, and political settings are considered external to the focal SES analyzed but are relevant to a broader context (figure 1).

Figure 1.

An interdisciplinary conceptual framework identifying relevant components or first-tier variables (quarters of the circle, labeled on the outside of the circle), subcomponents (inside the circle), and second-tier variables (below) to analyze wildlife trade with a focus on Southeast Asia, modeled after Ostrom (2009)’s social–ecological systems framework.

Iterative exploration across disciplines

Our integrated framework enables exploration of variables and data sets that combine the biological information of trade-targeted populations with other information on how people engage in the trade of these populations at multiple scales. The selection and outlining of second-tier variables and attributes can be helpful to explore the dynamics and interconnections of a system across scales, to test assumptions about the drivers of wildlife trade, and to test combined policy interventions to identify points and locations in the trade chain where interventions are likely to have the greatest impact. We explore below some examples of how integration and exploration of different disciplinary approaches and technologies illuminate the complexity of wildlife trade in Southeast Asia.

Biology

Two major problems for law enforcement and the study of taxa in the trade are species identification and product provenance, often because products have been processed before being sold in markets. Sophisticated techniques can help in assigning species and in identifying wildlife products (Ogden et al. 2009, Alacs et al. 2010). DNA barcoding, for instance, has been used successfully over several years for many different groups of plants and animals (Hebert et al. 2003, Dawnay et al. 2007, Eaton et al. 2010). This technique has not been applied widely in Southeast Asia because of limited access to molecular laboratories. The situation is expected to change quickly because DNA amplification and sequencing have become more accessible and inexpensive. Indeed, a growing number of wildlife trade studies in Asia employ DNA to investigate species under threat (e.g., Chen et al. 2015, Zhang et al. 2015). By combining DNA barcoding with morphological, anthropological, and socioeconomic data, researchers can clarify the patterns, scales, and drivers of wildlife trade; determine hotspots of trade activities; and identify the taxa under critical pressure.

Anthropology

Noneconomic social and cultural elements are often neglected in studies that integrate ecological and economic factors for decision-making (Fagerholm et al. 2012), and social, cultural, and political contexts can play significant roles in supporting or preventing wildlife trade (figure 1). Strong governance, regulations, and enforcement of regulations, for instance, can vary across regions, as can cultural norms regarding trade. A better understanding of why and when individual actors participate in trade—what social and cultural forces and norms drive hunting, subsistence uses, and market activities, such as valuing of rarity or connection to identity—is crucial to sustainable management and situated governance. For example, slow lorises (genus Nycticebus) seem to be subject to opportunistic or incidental exploitation for uses that vary widely from meat to medicine to pets depending on both the ethnic group and the region under study (Thach et al. in press). Also, methods such as social-network analysis, developed first in sociology but used in anthropology and other fields, can be applied to explore the importance of social networks as drivers and operators of wildlife trade chains (Freeman 2004).

Economics

Traditional economic models are anthropocentric and analyze human uses of ecosystems for production and consumption activities. In contrast, over the past two decades, there has been a spate of interest in bioeconomic modeling, an exercise that employs both economic and biophysical components, largely through the application of econometrics. Although econometric models have been applied to the bushmeat trade in Africa (e.g., Skonhoft 1998, Fischer et al. 2011), analyses of the Asian wildlife trade to date have been limited to characterizing trade chains or quantification of species, consumption patterns, and profits in trade at particular locations (e.g., Sandalj et al. 2016, Shairp et al. 2016); very few studies have used models to illustrate broader or more complex trade dynamics across sites.

Although such interdisciplinary empirical analyses constitute a step in the right direction, successful integration of ecological phenomena remains a major challenge because of sharp differences in disciplinary foci, mindsets, and vocabulary. This is beginning to change, however, with the advent of SES models. An important element of SES frameworks that has not been examined in previous studies is how to operationally connect data, hypotheses, and questions from different disciplines. The interdisciplinary SES framework that we outline in figure 1 can also be used to iteratively investigate different assumptions supported by data from any discipline included in the framework and to pinpoint key interactions and outcomes of the system. For example, if there is initial evidence from interview-derived data suggesting that trade products are transported from southern to northern Vietnam, it can be articulated as a preliminary hypothesis. This hypothesis can be further supported using patterns inferred from forensic DNA barcoding of trade confiscations or another biological approach (figure 2). Other types of data (e.g., transportation information) can be used to further triangulate the nature of interactions and outcomes along this dimension of the system.

Figure 2.

Iterative investigation of different research questions, assumptions, and hypotheses can be supported by data from different disciplines included in the social–ecological systems framework. The arrows represent exit from investigation after sufficient support for a hypothesis toward an understanding of the interactions and outcomes of the system (after DeSalle et al. 2005).

Operationalizing the framework

SES models developed from the perspective of a single discipline, such as resource economics, applied ecology, or fisheries science, tend to oversimplify either the ecological or the social domain and often fall short in exploring and explaining the social–ecological feedback loops that drive the development of the coupled SES (Schlüter et al. 2014). In particular, the ecology component of the SES framework has been underdeveloped; however, policy recommendations are more likely to stem from SES research that includes both ecological and social variables (Rissman et al. 2017). Under an interdisciplinary SES framework, as is proposed in figure 1, process- and pattern-oriented submodels or component models for different system components or variables (e.g., econometric dichotomous choice models to predict actor behavior in relation to hunting) can be bundled into a suite of models using knowledge and theories from diverse disciplines to further explore interactions and outcomes at various scales (figure 1).

Challenges to the operationalization of SES frameworks via quantitative or semiquantitative models (e.g., process-oriented, decision-making, general equilibrium, general algebraic systems, dynamic systems, fuzzy-logic cognitive mapping, or input–output models) include (a) parameterization of dynamic processes to account for scale, as well as cultural, biological, and economic change, and (b) integrating spatially explicit variables with other factors. The recent operationalization of SES frameworks into models has accounted for dynamic scales by distinguishing between different levels of aggregation, such as individual actors versus groups of actors, as well as individual resource units versus populations of resource units (Hinkel et al. 2014). Others have clarified hierarchies of process relationships and interactions among components through influence diagramming and the top-down unpacking of process relationships until changes in all relevant variables are explained (Schlüter et al. 2014). Making explicit the underlying assumptions of component and systems models will be particularly important to integrate effectively across inputs and assumptions that stem from the conceptual backgrounds of different disciplines (Schlüter et al. 2014).

Rather than prescribe a particular modeling or analysis approach to implement our framework, analysis should be tailored to the specific data-driven requirements of a given research question and the associated considerations of statistical assumptions and power and should remain open to qualitative and thematic approaches. For example, below, we describe our analysis under development for key trade-targeted species in Indochina, where we are integrating regression approaches with qualitative analysis. Simply put, qualitative research can support internal validity (sensu Drury et al. 2011), meaning that data represent the phenomenon under study as a complement to the external validity of quantitative data.

Key trade-targeted species

The Southeast Asian wildlife trade involves a huge diversity of plants and animals. Although we focus here on animal groups, plants are also heavily traded in Southeast Asia but possibly at different scales and influenced by different socioeconomic drivers (e.g., orchids and cycads; CITES Vietnam 2008). In terms of taxonomic groups, turtles, pangolins, and snakes have been most traded internationally. Other heavily traded groups include civet, muntjac, bear, primate, sambar, otter, and serow (Nguyen 2008, TRAFFIC and WCS 2004). The abundance of many trade-targeted animal species in Southeast Asia has declined severely over the past decade. However, in some cases, local extinctions may be linked to wildlife trade by little more than assumed association because key information on distribution, taxonomy, and population status is lacking for many trade-targeted species, especially in Vietnam and Indochina (CITES Vietnam 2008, Nguyen 2008, TRAFFIC 2008, Benitez-López et al. 2017). Guidance from our SES framework might help to prioritize data collection. For example, a great deal of trade data, such as the number of seizures, specimens, and species in the trade at both regional and local scales, are available, but data on the population status of traded species are generally limited. The latter should therefore be a focus of future programs to help link trade to the local extinction of species and/or populations.

Research that narrows to a suite of focal species could serve to investigate multiple scales of trade within a hierarchical SES research framework. Candidate species groups should be those for which wildlife trade is their major threat and that are subject to local, regional, or international demand, advancing our understanding of the multiple scales of wildlife trade in the region. In addition, data on their taxonomy, genetic patterns, distribution, and level of exploitation should be available for hypothesis testing within the framework. In our work, we have identified four focal groups of trade-targeted species for which sufficient data are available as per the categories above but that differ in their relative prevalence in trade across scales to test hypotheses about scales and drivers of wildlife trade in Vietnam or Indochina: turtles, muntjacs, pangolins, and slow lorises.

With the exception of some of the turtles and muntjac species, these groups are overall widespread and taxonomically diverse. However, a majority of species in the two aforementioned groups is traded in two vastly different networks. Although most turtle species in mainland Southeast Asia are hunted for export, muntjacs are often consumed domestically (TRAFFIC and WCS 2004, Nguyen 2008). Trade-targeted species, such as turtles and pangolins, are under immense pressures from rising demands of the international trade. As turtle and pangolin populations decline, their value in the trade is increasing at rates greater than inflation (Newton et al. 2008), exhibiting an anthropogenic allee effect, in which the extinction of rare species is influenced by human value attributed to rarity (Courchamp et al. 2006). Because of the nature of turtle and pangolin trade, namely their rarity and high price, all pangolins and turtles caught in local villages are sold to traders for sale in urban or international markets. Therefore, data on most turtle and pangolin trade may not be able to tell us very much about local scales of trade. On the other hand, muntjacs are suitable for studies documenting the nature of the trade at the local scale because of their domestic consumption.

Slow lorises (genus Nycticebus) are small, nocturnal primates. Slow lorises are widespread; have naturally low densities; and are in high demand for traditional medicines, as pets, and for food and are also traded internationally for these purposes (Nekaris et al. 2010). Despite all slow lorises having protected status across their range, enforcement of this status remains quite neglected compared with that for other higher-profile animals (Beyle et al. 2014). Importantly, traded species are not necessarily traded in isolation; a targeted species may be opportunistically, incidentally, or accidentally exploited when hunters are looking for more common or other species (Branch et al. 2013). Because of their natural low densities (rarity), slow lorises seem to be subject to opportunistic or incidental exploitation, depending on the area under study (Thach et al. in press). More research needs to be done both across and within species, in the latter case focusing on how the same species could be exploited in different ways at different scales and by different people. Data on highly targeted species alone may not be able to tell us very much about other species, and it might be quite difficult to get unbiased information from hunters and traders on the targeted species.

In our preliminary analysis on slow loris trade, iterative exploration including qualitative methods and analysis of key informant interviews was essential to understanding why people engage in trade and also to accurately characterize trade pathways. We have used genetic information to identify a pygmy slow loris confiscated by Vietnamese authorities in northern Vietnam as originating from southern Vietnam, supporting a trend of trafficking from southern Vietnam to northern Vietnam. Our interviews with key informants confirm this trend but also suggest some movement from central to southern Vietnam (Thach et al. in press). However, none of our confiscated samples from southern Vietnam show genetic provenance from northern or central Vietnam. Together, our data sets, collected and integrated within our framework, show a more complicated spatial pattern of trade than would be inferred by using only one method and have inspired a next set of iterative research questions that could be answered by integrating new sources of data within our integrative framework, such as transportation information: Is trade more frequent in one direction than the other? Are prices and uses different in trade going different directions? Where and how do intermediaries sort pricing and routes? Interventions that might be informed by the outcomes of this research might include activities targeted at sorting points that are tailored to the particular drivers in each direction, which may differ.

Building and strengthening technical and interdisciplinary capacity for integrative approaches

A key challenge in this effort will be building the capacity for effective interdisciplinary teams of researchers enabled to operationalize the iterative exploration of wildlife trade within a SES framework. Our framework originated in the lead authors’ backgrounds in evolutionary biology, and to complete our framework development, we built a team that includes anthropologists and economists. In addition, integration and increased collaboration with legal, anticorruption, and governance research fields will be essential to bring the framework to action at multiple scales (figure 1; e.g., Gibbs et al. 2010, Gore 2011). Interdisciplinary and international teams must negotiate conceptual differences; theories of knowledge; research ethics requirements; power dynamics; disciplinary prejudices; and challenges in communication, infrastructure, and logistics. Effective interdisciplinary collaborations require a great deal of work to implement, including team leadership that is committed to true conceptual integration among carefully selected team members who collaborate toward a cocreated research question (Black and Copsey 2014, Pooley et al. 2014).

Although the integrative framework requires well-rounded research capabilities, we highlight here the need for strengthening key areas, which, we argue, currently fall short of the standard for quality interdisciplinary research, especially in our region of focus. As a key component of the integrative framework developed here, DNA forensic and barcoding tools should be made widely available to facilitate wildlife trade management and hypothesis testing for a better understanding of the critical parameters—such as the scale, driver, and pattern—of the complex conservation threat (UNODC 2016). Recent advances in molecular technologies have led to a rapid increase in the application of DNA barcoding and other assignment tools to wildlife trade (e.g., Eaton et al. 2010, Chen et al. 2015, Zhang et al. 2015). Recognizing the advantages of the method, Pakistan became the first country in Asia to adopt DNA barcoding as a technique to curb illegal wildlife trade (Shahid 2015). Other countries are also considering the use of DNA analyses as an official wildlife enforcement tool (TRAFFIC 2015).

Currently, however, infrastructure, such as comprehensive DNA databases, is not ready to support comprehensive use of the technique. GenBank data are not well curated, and many available sequences are missing key information, such as locality. The few available curated databases, such as DNA Surveillance and DNABUSHMEAT, only cover specific taxonomic groups, most often mammals (Ross et al. 2003, Gaubert et al. 2015). For other lesser-known but widely traded vertebrates, such as turtles and other reptile species, resources have not been developed. To better control the wildlife trade, it is crucial to develop such a DNA database for range countries in Southeast Asia. As a first step, the database should have representatives of all vertebrates protected under the law in the countries for wildlife trade enforcement. DNA barcoding regions for the database could include the mitochondrial genes, cytochrome b or the cytochrome c oxidase subunit 1 (COI), because they are the markers of choice in wildlife forensic science (Alacs et al. 2010).

Other species that are currently not protected under law but have been heavily traded should also be included in the database in the likelihood that these species will be regulated in the future. More importantly, multiple sequences from geographically isolated populations of the targeted species should be incorporated into the database to help determine trade patterns, hotspots of trade activities, or populations under a high level of harvesting pressure. Recent studies demonstrate that such a fine-scale population assignment is particularly informative for wildlife trade management (e.g., Zhang et al. 2015), especially to trace geographic provenance and provide detail to supplement data from other disciplines within our integrative framework.

There are many challenges in developing a database for wildlife trade enforcement and research within the interdisciplinary framework. Its development requires collaboration between a wide variety of research institutions, including natural-history museums, nongovernment organizations, universities, and other research institutes from different countries in the region. This involves establishing data-sharing mechanisms among participating organizations. In addition, because funding for biodiversity research is in serious shortage (Amato and DeSalle 2012), this could prove a daunting task without support from governments and international funding agencies.

Conclusions

In summary, we believe that complex conservation problems merit interdisciplinary frameworks such as the one we have developed and described here. Our framework will allow researchers to test assumptions about how different aspects of a system interact and where there are nonlinearities in feedback loops across scales and dimensions. Our approach is intended to guide the holistic study of complex wildlife trade systems rather than to prescribe specific policy actions, which should be assessed by policymakers and managers in specific sociopolitical contexts on the basis of new information produced under the framework. However, the ideas put forward in our framework also relate to broader discussions in conservation aimed at intervention design and planning. The Open Standards (OS) for the Practice of Conservation (CMP 2013) is a tool to facilitate adaptive management in planning, implementing, and monitoring conservation initiatives. The OS fosters transparency by making explicit assumed causal relationships between strategies and anticipated outcomes (Schwartz et al. 2012). Our framework could be helpful to inform the process by which teams come to and question their stated assumptions during the process of formulation and help to promote systems analyses of problems. In the future, we expect to collaborate with more enforcement-focused organizations, such as the Society for Wildlife Forensics, to bridge holistic understanding guided by the framework to specific enforcement outcomes that avoid one-size-fits-all solutions and pinpoint where to invest effort to address problems such as wildlife trade in Southeast Asia.

Capturing the complexity of cross-scale interactions in a wildlife trade system does not mean that management needs to be so complicated and convoluted that it will no longer be feasible; different management strategies can be tailored to focus on different dimensions of the social–ecological system, keeping in mind how they influence and are influenced by other aspects of the system (Sterling et al. 2010). This systems perspective helps to direct initial questions toward those that are tractable and appropriate and away from fixes that fail. Strategic management approaches can be targeted to the needs and strengths of specific regions or scales; for example, if variables related to local actors are found to be the most important drivers of trade at the local scale, interventions can focus on improving relationships among relevant stakeholders. If variables related to governance are found to be the most important drivers at the national scale, interventions may focus on improving institutional arrangements (Leslie et al. 2015). Capacity development and database development and sharing will be key to acting on recommendations derived from the framework analysis in order to address the critical issue of wildlife trade in Southeast Asia.

Acknowledgments

We are grateful to the three anonymous reviewers for their comments on previous versions of this manuscript. We also thank Rob DeSalle for inspiration, Nadav Gazit for graphic design, and collaborators and student research assistants on the ongoing larger study: Marina Kenyon, Badrul Zain, Khoi Nguyen, Huan X. Nguyen, Thang T. Nguyen, Thong V. Pham, Thanh V. Nguyen, Ha Duong, Giang Cao, Elora Lopez, Daniel Veronese, Ngoc Vu, Anna Panariello, and Bonnie Yates from the USFWS Forensic Laboratory. We also thank Lien T. Tran, Hiep M. Nguyen, Pam McElwee, Christian Roos, Anna Nekaris, Ha M. Nguyen, Thang V. Hoang, Duc M. Hoang, and Tilo Nadler for support, advice, and discussion.

Funding statement

This material is based on work supported by US National Science Foundation Grant no. CHE-1313908, the Center for Biodiversity and Conservation at the American Museum of Natural History, the Margot Marsh Biodiversity Foundation, the Eppley Foundation for Research, the Disney Worldwide Conservation Fund, the Critical Ecosystem Partnership Fund, the Turtle Conservation Fund, the NAGAO Natural Environment Foundation, and USAID-PEER Science Project no. 3–149. The authors’ views expressed in this publication do not necessarily reflect the views of the US Agency for International Development or the US Government.

References cited

Alacs
E
,
Georges
A
,
FitzSimmons
N
,
Robertson
J
.
2010
.
DNA detective: A review of molecular approaches to wildlife forensics
.
Forensic Science, Medicine, and Pathology
6
:
180
194
.

Amato
G
,
DeSalle
R
.
2012
.
Assessing biodiversity funding during the sixth extinction
.
Bioessays
34
:
658
660
.

Benitez-López
A
,
Alkemade
R
,
Schipper
AM
,
Ingram
DJ
,
Verweij
PA
,
Eikelboom
JAJ
,
Huijbregts
MAJ
.
The impact of hunting on tropical mammal and bird populations
.
Science
356
:
180
183
.

Bennett
EL.
2011
.
Another inconvenient truth: The failure of enforcement systems to save charismatic species
.
Oryx
45
:
476
479
.

Beyle
J
,
Bguyen
VQ
,
Hendrie
D
,
Nadler
T
.
2014
.
Primates in the illegal wildlife trade in Vietnam
.
43
50
in
Nadler
T
,
Brockman
DK
, eds.
Primates of Vietnam
.
Endangered Primate Rescue Center
,
Vietnam
.

Black
SA
,
Copsey
JA
.
2014
.
Purpose, process, knowledge and dignity in interdisciplinary projects
.
Conservation Biology
28
:
1139
1141
.

Branch
TA
,
Lobo
AS
,
Purcell
SW
.
2013
.
Opportunistic exploitation: An overlooked pathway to extinction
.
Trends in Ecology and Evolution
28
:
409
413
.

Brashares
JS
,
Golden
CD
,
Weinbaum
K
,
Barrett
C
,
Okello
G
.
2011
.
Economic and geographic drivers of wildlife consumption in rural Africa
.
Proceedings of the National Academy of Sciences
108
:
13931
13936
.

Brooks
EGE
,
Roberton
SI
,
Bell
DJ
.
2010
.
The conservation impact of commercial wildlife farming of porcupines in Vietnam
.
Biological Conservation
143
:
2808
2814
.

Chen
J
,
Jiang
Z
,
Li
C
,
Ping
X
,
Cui
S
,
Tang
S
,
Chu
H
,
Liu
B
.
2015
.
Identification of ungulates used in a traditional Chinese medicine with DNA barcoding technology
.
Ecology and Evolution
5
:
1818
1825
.

[CITES Vietnam] Convention on International Trade in Endangered Species Vietnam
.
2008
.
Report on the Review of Vietnam's Wildlife Trade Policy
.
Centre for Natural Resources and Environmental Studies, Forest Protection Department, United Nations Environment Programme, CITES
,
University of Geneva Graduate Institute of Development Studies
.

[CMP] Conservation Measures Partnership
.
2013
.
Open Standards for the Practice of Conservation, version 3.0
. ().

Costanza
R
,
Wainger
L
,
Folke
C
,
Maler
K-G
.
1993
.
Modeling complex ecological economic systems
.
BioScience
43
:
545
555
.

Courchamp
F
,
Angulo
E
,
Rivalan
P
,
Hall
RJ
,
Signoret
L
,
Bull
L
,
Meinard
Y
.
2006
.
Rarity value and species extinction: The anthropogenic allee effect
.
PLOS Biology
4
(
art. e415
).

Dawnay
N
,
Ogden
R
,
McEwing
R
,
Carvalho
GR
,
Thorpe
RS
.
2007
.
Validation of the barcoding gene COI for use in forensic genetic species identification
.
Forensic Science International
173
:
1
6
.

DeSalle
R
,
Egan
MG
,
Siddall
M
.
2005
.
The unholy trinity: Taxonomy, species delimitation and DNA barcoding
.
Philosophical Transactions of the Royal Society B
360
:
1905
1916
.

Donovan
D.
2004
.
Cultural underpinnings of the wildlife trade in Southeast Asia
.
88
111
in
Knight
J
, ed.
Wildlife in Asia: Cultural Perspectives
.
Routledge Curzon
.

Douglas
LR
,
Alie
K
.
2014
.
High-value natural resources: Linking wildlife conservation to international conflict, insecurity, and development concerns
.
Biological Conservation
171
:
270
277
.

Drury
R.
2009
.
Reducing urban demand for wild animals in Vietnam: Examining the potential of wildlife farming as a conservation tool
.
Conservation Letters
2
:
263
270
.

Drury
R.
.
2011
.
Hungry for success: Urban consumer demand for wild animal products in Vietnam
.
Conservation and Society
9
:
247
257
.

Drury
R
,
Homewood
K
,
Randall
S
.
2011
.
Less is more: The potential of qualitative approaches in conservation research
.
Animal Conservation
14
:
18
24
.

Duffy
R
,
St John
FAV
,
Buscher
B
,
Brockington
D
.
2016
.
Toward a new understanding of the links between poverty and illegal wildlife hunting
.
Conservation Biology
30
:
14
22
.

Eaton
MJ
,
Meyers
GL
,
Kolokotronis
SO
,
Leslie
MS
,
Martin
AP
,
Amato
G
.
2010
.
Barcoding bushmeat: Molecular identification of Central African and South American harvested vertebrates
.
Conservation Genetics
11
:
1389
1404
.

Fagerholm
N
,
Kayhko
N
,
Ndumbaro
F
,
Khamis
M
.
2012
.
Community stakeholders’ knowledge in landscape assessments: Mapping indicators for landscape services
.
Ecological Indicators
18
:
421
433
.

Fischer
C
,
Muchapondwa
E
,
Sterner
T
.
2011
.
A bio-economic model of community incentives for wildlife management under CAMPFIRE
.
Environmental Resource Economics
48
:
303
319
.

Foerster
S
,
Wilkie
DS
,
Morelli
GA
,
Demmer
J
,
Starkey
M
,
Telfer
P
,
Steil
M
,
Lewbel
A
.
2011
.
Correlates of bushmeat hunting among remote rural households in Gabon, Central Africa
.
Conservation Biology
26
:
335
344
.

Freeman
L.
2004
.
The Development of Social Network Analysis
.
Empirical Press
.

Gaubert
P
,
Njiokou
F
,
Olayemi
A
,
Pagani
P
,
Dufour
S
,
Danquah
E
,
Nutsuakor
MEK
,
Ngua
G
,
Missoup
AD
,
Tedesco
PA
.
2015
.
Bushmeat genetics: Setting up a reference framework for the DNA typing of African forest bushmeat
.
Molecular Ecology Resources
15
:
633
651
.

Gibbs
CE
,
Gore
MI
,
McGarrell
EF
,
Rivers
L
.
2010
.
Introducing conservation criminology: Towards interdisciplinary scholarship on environmental crimes and risks
.
British Journal of Criminology
50
:
124
144
.

Golden
CD
,
Gupta
AC
,
Vaitla
B
,
Myers
SS
.
2016
.
Ecosystem services and food security: Assessing inequality at community, household, and individual scales
.
Environmental Conservation
43
:
381
388
.

Gore
MI.
2011
.
The science of conservation crime
.
Conservation Biology
25
:
659
661
.

Greatorex
ZF
et al. 
2016
.
Wildlife trade and human health in Lao PDR: An assessment of the zoonotic disease risk in markets
.
PLOS ONE
11
(
art. e0150666
).

[Hanoi Statement] Hanoi Statement on Illegal Wildlife Trade
.
2016
.
Hanoi Conference on Illegal Wildlife Trade; 17–18 November 2016
,
Hanoi, Vietnam
.

Hebert
PD
,
Cywinska
A
,
Ball
SL
.
2003
.
Biological identifications through DNA barcodes
.
Proceedings of the Royal Society B
270
:
313
321
.

Hinkel
J
,
Bots
P
,
Schlüter
M
.
2014
.
Enhancing the Ostrom social–ecological system framework through formalization
.
Ecology and Society
19
(
art. 51
).

Jepson
P
,
Ladle
RJ
.
2009
.
Governing bird-keeping in Java and Bali: Evidence from a household survey
.
Oryx
43
:
364
374
.

Lee
TM
,
Sigouin
A
,
Pinedo-Vasquez
M
,
Nasi
R
.
2014
.
The Harvest of Wildlife for Bushmeat and Traditional Medicine in East, South and Southeast Asia
.
Center for International Forestry Research
.

Leslie
HM
et al. 
2015
.
Operationalizing the social–ecological systems framework to assess sustainability
.
Proceedings of the National Academy of Sciences
112
:
5979
5984
.

MacMillan
D
,
Nguyen
Q
.
2014
.
Factors influencing the illegal harvest of wildlife by trapping and snaring among the Katu ethnic group in Vietnam
.
Oryx
48
:
304
312
.

McElwee
P.
2004
.
Becoming socialist or becoming Kinh? Government policies for ethnic minorities in the Socialist Republic of Viet Nam
.
182
213
in
Duncan
CR
, ed.
Civilizing the Margins: Southeast Asian Government Policies for the Development of Minorities
.
Cornell University Press
.

McGinnis
M
,
Ostrom
E
.
2014
.
Social–ecological system framework: Initial changes and continuing challenges
.
Ecology and Society
19
(
art. 30
).

Nadal
A
,
Aguayo
F
.
2014
.
Leonardo's sailors: A review of the economic analysis of wildlife trade
.
Leverhulme Centre for the Study of Value, University of Manchester
.
Working Paper Series no. 6
.

Nekaris
KAI
,
Shepherd
CR
,
Starr
C
,
Nijman
V
.
2010
.
Exploring cultural drivers for wildlife trade via an ethnoprimatological approach: A case study of slender and slow lorises (Loris and Nycticebus) in South and Southeast Asia
.
American Journal of Primatology
72
:
877
886
.

Newton
P
,
Nguyen
V
,
Roberton
SI
,
Bell
DJ
.
2008
.
Pangolines in peril: Using local hunters’ knowledge to conserve elusive species in Vietnam
.
Endangered Species Resarch
6
:
41
53
.

Nguyen
VS.
2008
.
Wildlife trading in Vietnam: Situations, causes, and solutions
.
Journal of Environment and Development
17
:
145
165
.

Nijman
V.
2010
.
An overview of international wildlife trade from Southeast Asia
.
Biodiversity and Conservation
19
:
1101
1114
.

Nyaki
A
,
Gray
S
,
Lepczyk
C
,
Skibins
J
,
Rentsch
D
.
2014
.
Local-scale dynamics and local drivers of bushmeat trade
.
Conservation Biology
28
:
1403
1414
.

Ogden
R
,
Dawnay
N
,
McEwing
R
.
2009
.
Wildlife DNA forensics: Bridging the gap between conservation genetics and law enforcement
.
Endangered Species Research
9
:
179
195
.

Ostrom
E.
2009
.
A general framework for analyzing sustainability of social–ecological systems
.
Science
325
:
419
422
.

Phelps
J
,
Shepherd
C
,
Reeve
R
,
Niissalo
M
,
Webb
E
.
2014
.
No easy alternatives to conservation enforcement: Response to Challender and Macmillan
.
Conservation Letters
7
:
495
496
.

Pooley
SP
,
Mendelsohn
JA
,
Milner-Gulland
E
.
2014
.
Hunting down the chimera of multiple disciplinarity in conservation science
.
Conservation Biology
28
:
22
32
.

Rissman
AR
,
Gillon
S
.
2017
.
Where are ecology and biodiversity in social–ecological systems research? A review of research methods and applied recommendations
.
Conservation Letters
10
:
86
93
.

Ross
H
,
Lento
G
,
Dalebout
M
,
Goode
M
,
Ewing
G
,
McLaren
P
,
Rodrigo
A
,
Lavery
S
,
Baker
C
.
2003
.
DNA surveillance: Web-based molecular identification of whales, dolphins, and porpoises
.
Journal of Heredity
94
:
111
114
.

Sandalj
M
,
Treydte
AC
,
Ziegler
S
.
2016
.
Is wild meat luxury? Quantifying wild meat demand and availability in Hue, Vietnam
.
Biological Conservation
194
:
105
112
.

Schlüter
M
,
Hinkel
J
,
Bots
P
,
Arlinghaus
R
.
2014
.
Application of the SES framework for model-based analysis of the dynamics of social–ecological systems
.
Ecology and Society
19
(
art. 36
).

Schwartz
MW
,
Deiner
K
,
Forrester
T
,
Grof-Tisza
P
,
Muir
MJ
,
Santos
MJ
,
Souza
LE
,
Wilkerson
ML
,
Zylerberg
M
.
2012
.
Perspectives on the open standards for the practice of conservation
.
Biological Conservation
155
:
169
177
.

Shahid
J.
2015
.
Pakistan adopts DNA barcoding to check illegal wildlife trade
.
Dawn.
(
1 September 2017; www.dawn.com/news/1203605
).

Shairp
R
,
Verissimo
D
,
Fraser
I
,
Challender
D
,
MacMillan
D
.
2016
.
Understanding urban demand for wild meat in Vietnam: Implications for conservation actions
.
PLOS ONE
11
(
art. e0134787
).

Skonhoft
A.
1998
.
Resource utilisation, property rights and welfare: Wildlife and the local people
.
Ecological Economics
26
:
67
80
.

Sterling
EJ
,
Gomez
A
,
Porzecanski
A
.
2010
.
A systemic view of biodiversity and its conservation: Processes, interrelationships, and human culture
.
Bioessays
32
:
1090
1098
.

Suarez
E
,
Morales
M
,
Cueva
R
,
Bucheli
VU
,
Zapata-Rios
G
,
Toral
E
,
Torres
J
,
Prado
W
,
Olalla
JV
.
2009
.
Oil industry, wild meat trade and roads: Indirect effects of oil extraction activities in a protected area in north-eastern Ecuador
.
Animal Conservation
12
:
364
373
.

Thach
HM
,
Le
MD
,
Vu
NB
,
Panariello
A
,
Sethi
G
,
Sterling
EJ
,
Blair
ME
.
2017
.
Slow loris trade in Vietnam: Exploring diverse knowledges and values
.
Folia Primatologica
.
In press
.

TRAFFIC
.
2008
.
What's Driving the Wildlife Trade? A Review of Expert Opinion on Economic and Social Drivers of the Wildlife Trade and Trade Control Efforts in Cambodia, Indonesia, Lao PDR and Vietnam
.
East Asia and Pacific Region Sustainable Development Department
,
World Bank
.

TRAFFIC
.
2015
.
Wildlife DNA forensic group established to combat illegal wildlife trade in SE Asia
.
TRAFFIC
.

TRAFFIC, [WCS] Wildlife Conservation Society
.
2004
.
Hunting and Wildlife Trade in Asia: Proceedings of a Strategic Planning Meeting of the Wildlife Conservation Society (WCS) and TRAFFIC
.
WCS, TRAFFIC
.

[UNODC] United Nations Office on Drugs and Crime
.
2016
.
World Wildlife Crime Report: Trafficking in Protected Species
.
UNODC
.

Van Vliet
N
,
Fa
J
,
Nasi
R
.
2015
.
Managing hunting under uncertainty: From one-off ecological indicators to resilience approaches in assessing the sustainability of bushmeat hunting
.
Ecology and Society
20
(
art. 7
).

Watzold
F
et al. 
2006
.
Ecological–economic modeling for biodiversity management: Potential, pitfalls, and prospects
.
Conservation Biology
20
:
1034
1041
.

Wittemyer
G.
2011
.
Effects of economic downturns on mortality of wild African elephants
.
Conservation Biology
25
:
1002
1009
.

Zhang
H
,
Miller
MP
,
Yang
F
,
Chan
HK
,
Gaubert
P
,
Ades
G
,
Fischer
GA
.
2015
.
Molecular tracing of confiscated pangolin scales for conservation and illegal trade monitoring in Southeast Asia
.
Global Ecology and Conservation
4
:
414
422
.