The wildlife trade is a major cause of species loss and a pathway for disease transmission. Socioeconomic drivers of the wildlife trade are influential at the local scale yet rarely accounted for in multinational agreements aimed at curtailing international trade in threatened species. In recent decades (1998–2018), approximately 421,000,000 threatened (i.e., CITES-listed) wild animals were traded between 226 nations/territories. The global trade network was more highly connected under conditions of greater international wealth inequality, when rich importers may have a larger economic advantage over poorer exporting nations/territories. Bilateral trade was driven primarily by socioeconomic factors at the supply end, with wealthier exporters likely to supply more animals to the global market. Our findings suggest that international policies for reducing the global wildlife trade should address inequalities between signatory states, possibly using incentive/compensation-driven programs modeled after other transnational environmental initiatives (e.g., REDD+).

Studies of ecosystem functions are gaining traction in the scientific community along with a growing consensus that losses in ecosystem functions have widespread consequences. Food webs, which are networks comprising all trophic interactions (represented by links) between taxa present in a community (represented by nodes), are important aspects of ecosystem functioning, yet a clear understanding of the factors and mechanisms influencing their assembly and structure is lacking. In our study, we addressed this fundamental question by investigating the respective roles of (1) environmental filtering and (2) biotic filtering, in governing food web structure. We did this by assessing the relationship between the network structure of five high‐resolution empirical tropical food webs and associated environmental and biotic covariates. Our data suggest that only environmental filtering is important in shaping food webs. Further, we found that the underlying ecological mechanism is a function of bottom‐up influences comprising resource levels, and to a lesser degree, resource type (i.e., terrestrial organic matter) available. Specifically, our data suggest high‐nutrient environments favor greater food web complexity. In the general context of community assembly, our findings add to existing knowledge of the process by demonstrating that environmental conditions previously shown to influence species assemblages can also drive trends in prevailing species interactions.

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Fresh waters are increasingly threatened by flow modification. Knowledge about the impacts of flow modification is incomplete, especially in the tropics where ecological studies are only starting to emerge in recent years. Using presence/absence data dated approximately four decades apart (~1966 to ~2010) from 10 tropical rivers, we assessed the changes in freshwater fish assemblage and food web after flow modification. The sites were surveyed with methods best suited to habitat conditions (e.g., tray/push netting for low‐order forest streams, visual surveys for canalised rivers and net casting for impounded rivers). With the presence/absence data, we derived and compared six measures of fish assemblage and food web structure: species richness, proportion of native species, overall functional diversity, native functional diversity, food web complexity and maximum trophic level. We found that changes in community assemblage and food web structure were not generalisable across modification regimes. In canalised sites, species richness and maximum trophic levels were lower in the second time period while the opposite was true for impounded sites. However, proportion of native species was consistently lower in the second time period across modification regimes. Changes in fish assemblages and food webs appear to be driven by species turnover. We recorded 79 cases of site‐specific extirpation and 117 cases of site‐specific establishment. Our data further suggest that turnover in assemblage is again contingent on flow‐modification regime. While the process was stochastic in canalised rivers, benthopelagic species were more likely to be extirpated from impounded rivers where species lost were replaced by predominantly alien fish taxa.