AME_4.8_386

Relevant information on indirect drivers is extremely limited at environmental scales (e.g. habitats, ecosystems, biomes), which in many cases may be more relevant than institutional scales (e.g. administrative, municipalities, provinces, countries) for IPBES assessments. In addition, internationally comparable data on indirect drivers are not always available for all countries and regions of the Americas being particularly limited for small economies.
The mechanisms by which direct drivers interact are poorly understood. The mechanisms include interactions between demographic parameters, evolutionary trade-offs and synergies and threshold effects of population size and patch occupancy on population persistence. Understanding how multiple drivers of global change interact to impact biodiversity and ecosystem services requires a multiscale approach as drivers act at from global to local scales, and their interactions have emergent properties (i.e. change with the scale). The lack of appropriate research is partially due to limited data availability and analytical issues in addressing interaction effects.
In the case of the Americas, for some regions, there is still substantial uncertainty associated to spatial and temporal magnitude of the drivers (e.g. area and spatial distribution of the different land-use classes and infrastructure maps, measurements and model forecasts for climate and nitrogen deposition, distribution of invasive species). For example, studies that quantify the impacts of invasive species on biodiversity and ecosystems are still very scarse, especially outside North America. In addition, there is very little information on the effects of nitrogen deposition on tropical forests, woodlands, savannas and grasslands (Bobbink et al., 2010). Likewise, in contrast to North America, no systematic surveys exist for pollutants, including agricultural chemicals, persistent organic pollutants and mercury, in South America, the Caribbean and Mesoamerica. Another major difficult to assess the effects of pesticides on biodiversity and ecosystem services is just knowing what pesticides are used, when and how much as well as having little information on the environmental occurrence of these same pesticides. Regarding climate change, the degree to which climate change in tundra and boreal ecosystems will promote fires and droughts is not well documented considering that these disturbances have major consequences for species productivity and dynamics in this region (Abbott et al., 2016; Pastick et al., 2017).
For some ecosystems, lack of consistent information on drivers of change is observed in all subregions of the Americas. Trends in land condition, and drivers of those trends, remain unstudied or understudied in most dryland areas across the Americas. Coastal aquatic and pelagic ocean biodiversity also remains poorly characterized throughout the Americas. Understanding how sensitive areas change in relation to regional- to global-scale processes, a mechanism to communicate the needs of people making decisions about local resources to scientists, and pathways to deliver scientific knowledge to decision makers remain prioritary needs for the region. At this time it is not possible to make a generalized statement of impacts of global changes in physical ocean dynamics and atmospheric carbon dioxide concentrations on coastal ecology. Another major unknown is the fate of plastic pollution in coastal regions of the Americas, as the amount of plastic pollution on the ocean surface is much less than the amount that is released to oceans, yet we know that many plastics can take hundreds of years to degrade (Clark et al., 2016).
A major limitation in the study and management of coastal zones around the world has been the lack of a capacity to collect, handle, and process repeated, frequent observations of aquatic and nearby wetland resources in an integrated manner to enable the detection of changes in the chemistry and in the diversity of wetland and aquatic organisms.
Regarding American mangroves, more data on consequences of nitrogen and phosphorus enrichment to nutrient cycling rates, fluxes and stocks, sediment microbial communities structure and functioning, and the resulting primary productivity in the different types of mangroves are needed, especially in underrepresented areas like South America (Reis et al., 2017). Information about oil contamination effects on sediment microbial communities and the effects of bioremediation techniques on microbial diversity in mangroves are also needed (Santos et al., 2011; Machado & Lacerda, 2004).
Improved management for overharvested species requires inventories, baselines, and monitoring knowledge of targeted species. Managers need to know population densities, sizes and trends, breeding and migration patterns, and ecological conditions they require. Understanding the threats that are causing their decline (e.g. trade markets) as well as traditional values and knowledge will assist both management and enforcement.
There are active efforts to organize partnerships and collaborations to observe biodiversity and ecosystem characteristics in the Americas. Specifically, a series of Biodiversity Observation Network efforts are being organized under the Group on Earth Observations with some of these are at the country level. Networks of regional observation systems that collaborate and share information, and that work jointly to understand biodiversity and ecosystems could provide support to existing national programs and contribute to address United Nations SDG.