Montane ecosystems are known for their high numbers of endemic species, unique climate conditions, and wide variety of ecosystem services such as water supply and carbon storage. Although many ecohydrological and climatic studies of montane environments have been carried out in temperate and boreal regions, few have been done in Neotropical regions. Hence, the objective of this review is to synthesize the existing literature on the main factors (biotic and abiotic) that influence vegetation distribution, functional traits, and ecohydrological processes and feedbacks in tropical montane ecosystems and to identify key knowledge gaps. Most of the literature used includes work conducted in Neotropical montane rainforests, cloud forests, and grass/scrublands (e.g., páramos, punas, and campos de altitude/rupestres). Fog is a major climatic attribute in tropical montane habitats. We found that fog regimes (frequency and intensity of fog events) influence both water inputs (i.e., canopy interception and foliar water uptake) and outputs (evapotranspiration) and represent an important driver of local species composition, dominance of plant functional types, and ecological functioning. The stability and conservation of tropical montane ecosystems depends on such ecohydrological fluxes, which are sensitive to increases in air temperature and changing precipitation and fog regimes. Furthermore, to better inform effective conservation and restoration strategies, more work is needed to elucidate how key ecohydrological processes are affected by land use conversion to agriculture and pasture lands, as human activities influence the water budgets in Neotropical montane watersheds not only at regional‐scales but also globally.

In response to increasing pressures on water resources, watershed services management programs are implemented throughout the tropics. These programs aim to promote land management activities that enhance the quantity and quality of water available to local communities. The success of these programs hinges on our ability to (a) understand the impacts of watershed interventions on ecohydrology; (b) model these impacts and design efficient management programs; and (c) develop strategies to overcome barriers to practical policy development, including resource limitations or the absence of baseline data. In this paper, we review opportunities in ecohydrological science that will help address these three challenges. The opportunities are grouped into measurement techniques, modelling approaches, and access to resources in our hyperconnected world. We then assess management implications of both the knowledge gaps and the new research developments related to the effect of land management. Overall, we stress the importance of policy‐relevant knowledge for implementing efficient and equitable watershed services programs in the tropics.

23Despite the potential of tropical montane forests to store and sequester substantial amounts of 24 carbon, little is known about the above ground biomass (AGB) and the factors affecting it in 25 these ecosystems, especially in Africa. We investigated the height-diameter allometry, AGB, 26 and related differences in AGB to taxonomic and structural forest attributes in three distinct 27 forest types (dry, mixed species and elfin) in three mountains of northern Kenya. We

As watershed management programs have become more common globally, so have efforts to support these initiatives through hydrologic modeling and monitoring. However, these efforts are often guided by oversimplified assumptions of how management programs work and the quantity, quality, and type of information needed to support their planning, implementation, and evaluation. Semi-structured interviews and focus groups with project managers, funders, and participants in three watershed management programs in the Atlantic Forest of Brazil revealed a range of hydrologic modeling and monitoring needs of watershed management programs. We identify five opportunities for hydrologic information to support overlapping management contexts: (1) inspire action and support, (2) inform investment decisions, (3) engage with potential participants, (4) prioritize location and types of activities at regional to national scales, and (5) evaluate program success. Within these opportunities, understanding who will use the information generated and how they will do so is critical to increasing the salience, credibility, and legitimacy of modeling efforts. Hydrologic modeling and monitoring play a small but critical role in the larger context of program conceptualization, design, implementation, and evaluation; grounding these efforts in local contexts supports watershed management projects in relevant and effective ways.Plain Language Summary Active land management for a variety of benefits, including sustaining and enhancing clean and ample water supplies, is becoming more common worldwide. To achieve these ends, watershed management programs need the support of hydrologic data and models, but promising efforts by the hydrologic community often go unused when the information program managers need is not well matched to modeling efforts. We interviewed a wide range of participants in water management programs in Brazil and found five key areas where modeling and monitoring can support these programs: (1) inspire action and support, (2) inform investment decisions, (3) engage with potential participants, (4) prioritize location and types of activities at regional to national scales, and (5) evaluate program success. Our study emphasizes the importance of focusing on who will use modeling results and tailoring efforts to meet these needs. When grounded in real-world contexts, hydrologic monitoring and modeling can play a small but critical role in supporting sustainable watershed management