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Summary Novel forms of drought are emerging globally, due to climate change, shifting teleconnection patterns, expanding human water use, and a history of human influence on the environment that increases the probability of transformational ecological impacts. These costly ecological impacts cascade to human communities, and understanding this changing drought landscape is one of today’s grand challenges. By using a modified horizon-scanning approach that integrated scientists, managers, and decision-makers, we identified the emerging issues in ecological drought that represent key challenges to timely and effective responses. Here we review the themes that most urgently need attention, including novel drought conditions, the potential for transformational drought impacts, and the need for anticipatory drought management. This horizon scan and review provides a roadmap to facilitate the research and management innovations that will support forward-looking, co-developed approaches to reduce the risk of drought to our socio-ecological systems during the 21st century.

New York Harbor is a large, iconic and complex body of water that has been extensively modified to support the development of a megacity. These modifications have affected the shorelines, water flow, water quality, habitats and living resources of the harbor. Changes in topography and bathymetry have altered the landscapes and seascapes of the region, largely to support an active shipping port and intense human settlement. New York Harbor has been transformed from a region dominated by marshy shorelines, extensive submersed oyster beds and obstructed entrances to the present-day harbor with hardened shorelines, dredged shipping channels and remnant oysters that are unsafe to consume. However, improvements in water quality, largely due to sewage treatment upgrades, combined with the natural flushing ability of the harbor, have served to help restore or improve the ecological resilience of New York Harbor. Social resilience of the region has been tested with both terrorist attacks and the widespread inundation associated with Superstorm Sandy. Both ecological and social resilience will need to be enhanced to sustain the future development of New York Harbor.

Identification and quantification of the nutrient sources supporting large, extended duration Karenia brevis blooms on the West Florida Shelf (WFS) in the eastern Gulf of Mexico are critical steps for effective bloom management and mitigation. Previous research had identified multiple (>12) potential nutrient sources available to K. brevis blooms on the WFS, which vary with bloom stage, location, biomass and bloom toxicity. This current study newly identified and quantified additional nitrogen (N) sources including water column nitrification, photochemical nutrient production, pelagic unicell N2 fixation by diazotrophs other than the colonial cyanobacterium Trichodesmium, and remineralization from seasonal Trichodesmium biomass decay and microzooplankton grazing (and estimated regeneration). Newly identified phosphorus (P) sources include remineralization from Trichodesmium biomass decay and microzooplankton grazing. In estuarine environments, benthic nutrient flux, mixotrophic consumption of picoplankton, nutrient release from zooplankton and microzooplankton grazing, photochemical nutrient production, and nitrification all can contribute up to 100% of the N and/or P requirements of small ( Given the complexity of K. brevis bloom dynamics, the multiple available nutrient sources on the WFS and the importance of regenerated N forms in supporting blooms, efforts to reduce potentially controllable nearshore nutrient inputs should be undertaken with the understanding that while they may lead to enhanced coastal water quality, they may not have an immediate impact on the frequency or magnitude of nearshore K. brevis blooms. Additionally, time lags in ecosystem responses or differences in the time scales on which various process operate may require multi-year assessments to determine how effective management practices are in relation to K. brevis blooms. Timely red tide related monitoring products that allow for effective focusing of monitoring needs for short-term prediction of impacts and targeted communication of scientific results to the public and stakeholders, remains the most effective means of K. brevis management.

Blooms of the toxin producing dinoflagellate Karenia brevis occur routinely on the West Florida Shelf of the Gulf of Mexico. Nutrient supplies are thought to play a large role in the formation and maintenance of these blooms. The role of top-down control has been less well studied, but grazing, or the lack thereof, on these toxic species may also enhance the formation of large biomass blooms in this region. Zooplankton community structure and copepod species composition were analyzed from samples collected on the West Florida Shelf (WFS) during a NOAA funded ECOHAB regional Karenia Nutrient Dynamics project during October 2007–2010. In 2008 there was no statistical difference in the abundance of zooplankton at bloom and non-bloom stations, however in 2009 there was a statistically significant difference (p

Along the Fresh Lake causeway on San Salvador Island, the Bahamas, the seed bank was compared to the above ground vegetation in May 2006. Vegetation was dominated by a shrub canopy of Conocarpus erectus. A 49 m transect was run along the south side of the Fresh Lake causeway, and 10 secondary transects were randomly run from it towards Fresh Lake. Percent above ground cover was determined, and soil cores were taken along secondary transects at 0, 1, and 2 m. Percent above ground cover was calculated in 15 × 15 cm quadrats, and 6.0 cm diameter × 7.5 cm deep soil samples (n = 30) were collected. Species diversity was low, with only Borrichia arborescens (1.7 %), Sporobolus virginicus (16.8 %) and a member of the Poaceae (