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The Arabian Peninsula borders the hottest reefs in the world, and corals living in these extreme environments can provide insight into the effects of warming on coral health and disease. Here, we examined coral reef health at 17 sites across three regions along the northeastern Arabian Peninsula (Persian Gulf, Strait of Hormuz and Oman Sea) representing a gradient of environmental conditions. The Persian Gulf has extreme seasonal fluctuations in temperature and chronic hypersalinity, whereas the other two regions experience more moderate conditions. Field surveys identified 13 coral diseases including tissue loss diseases of unknown etiology (white syndromes) in Porites, Platygyra, Dipsastraea, Cyphastrea, Acropora and Goniopora; growth anomalies in Porites, Platygyra and Dipsastraea; black band disease in Platygyra, Dipsastraea, Acropora, Echinopora and Pavona; bleached patches in Porites and Goniopora and a disease unique to this region, yellow-banded tissue loss in Porites. The most widespread diseases were Platygyra growth anomalies (52.9% of all surveys), Acropora white syndrome (47.1%) and Porites bleached patches (35.3%). We found a number of diseases not yet reported in this region and found differential disease susceptibility among coral taxa. Disease prevalence was higher on reefs within the Persian Gulf (avg. 2.05%) as compared to reefs within the Strait of Hormuz (0.46%) or Oman Sea (0.25%). A high number of localized disease outbreaks (8 of 17 sites) were found, especially within the Persian Gulf (5 of 8 sites). Across all regions, the majority of variation in disease prevalence (82.2%) was associated with the extreme temperature range experienced by these corals combined with measures of organic pollution and proximity to shore. Thermal stress is known to drive a number of coral diseases, and thus, this region provides a platform to study disease at the edge of corals’ thermal range.

Tidal marshes are threatened coastal ecosystems known for their capacity to store large amounts of carbon in their water-logged soils. Accurate quantification and mapping of global tidal marshes soil organic carbon (SOC) stocks is of considerable value to conservation efforts. Here, we used training data from 3710 unique locations, landscape-level environmental drivers and a global tidal marsh extent map to produce a global, spatially explicit map of SOC storage in tidal marshes at 30 m resolution. Here we show the total global SOC stock to 1 m to be 1.44 Pg C, with a third of this value stored in the United States of America. On average, SOC in tidal marshes’ 0–30 and 30–100 cm soil layers are estimated at 83.1 Mg C ha −1 (average predicted error 44.8 Mg C ha −1 ) and 185.3 Mg C ha −1 (average predicted error 105.7 Mg C ha −1 ), respectively. A new study shows the total global SOC stock of 1 m in the world’s tidal marshes to be 1.44 Pg C. On average, SOC in tidal marshes’ 0–30 cm and 30–100 cm soil layers are estimated at 83.1 Mg C ha −1 and 185.3 Mg C ha −1 , respectively.

Seagrass sediments accumulate high amounts of organic carbon, but they are threatened by human activities and their global extent continues to shrink. Simultaneously, there is interest in including seagrass carbon accumulation in countries’ Nationally Determined Contributions (NDCs). We used the InVEST Coastal Blue Carbon Model to estimate sediment organic carbon (SOC) accumulation over 100 years in seagrass of the Bahama Banks, the world’s largest seagrass meadow. Using seagrass maps and sediment core measurements, we modeled SOC accumulation in two scenarios: (1) 1% seagrass area loss per year, the Business As Usual scenario (BAU); (2) restoration of seagrass extent to that of 30 years prior by 2120, meeting the goals of the Kunming-Montreal global biodiversity framework. With a conservative initial seagrass extent, by 2120, the SOC accumulation was 90.6 Mt CO 2 eq (24.0 autochthonous Mt CO 2 eq) in the BAU and 703.7 Mt CO 2 eq (186.5 autochthonous Mt CO 2 eq) in the restoration scenario, and average additional SOC accumulation was 611.0 Mt CO 2 eq (161.9 autochthonous Mt CO 2 eq). Using a high estimate of initial seagrass extent, by 2120, the net SOC accumulation was 155.4 Mt CO 2 eq (41.2 autochthonous Mt CO 2 eq) in the BAU and 1058.2 Mt CO 2 eq (280.4 autochthonous Mt CO 2 eq) in the restoration scenario, and additional SOC accumulation was 902.8 Mt CO 2 eq (239.2 autochthonous Mt CO 2 eq). The potential for either SOC accumulation or losses to occur if seagrass extent continues to decline highlights uncertainty around whether Bahamian seagrass meadows will remain a net carbon sink. The additional accumulation of autochthonous carbon if seagrasses were restored was comparable in scale to the annual greenhouse gas emissions of The Bahamas, suggesting potential for seagrass restoration to contribute to the country’s NDCs and broader climate mitigation strategies.

Harvest of wild animals and plants is pervasive, exerts ecological and evolutionary pressure on populations, and is known to drive rapid changes in organismal traits. Although the factors that lead to rapid trait changes have received increased attention, the ecological consequences of harvest-driven trait changes are less appreciated. We review recent evidence that harvest-driven trait changes can affect community and ecosystem processes. Growing experimental evidence, modeling studies, and field observations have revealed that common responses to harvest include changes in life-history and behavioral traits, which have the potential to reshape the ecology of harvested systems. On the basis of existing evidence, we propose a set of general mechanisms that link harvest-driven trait changes to ecological processes, including trophic cascades, nutrient dynamics, keystone interactions, ecosystem stability, and habitat use. Managing harvested ecosystems sustainably may require strategies that account for harvest-driven trait changes. We recommend that trait changes be monitored closely as part of ecosystem-based management plans, especially in cases where targeted traits are known to affect important aspects of ecosystem function.

Echinoderms, positioned taxonomically at the base of deuterostomes, provide an important system for the study of the evolution of the immune system. However, there is little known about the cellular components and genes associated with echinoderm immunity. The 2013-2014 sea star wasting disease outbreak is an emergent, rapidly spreading disease, which has led to large population declines of asteroids in the North American Pacific. While evidence suggests that the signs of this disease, twisting arms and lesions, may be attributed to a viral infection, the host response to infection is still poorly understood. In order to examine transcriptional responses of the sea star Pycnopodia helianthoides to sea star wasting disease, we injected a viral sized fraction (0.2 μm) homogenate prepared from symptomatic P. helianthoides into apparently healthy stars. Nine days following injection, when all stars were displaying signs of the disease, specimens were sacrificed and coelomocytes were extracted for RNA-seq analyses. A number of immune genes, including those involved in Toll signaling pathways, complement cascade, melanization response, and arachidonic acid metabolism, were differentially expressed. Furthermore, genes involved in nervous system processes and tissue remodeling were also differentially expressed, pointing to transcriptional changes underlying the signs of sea star wasting disease. The genomic resources presented here not only increase understanding of host response to sea star wasting disease, but also provide greater insight into the mechanisms underlying immune function in echinoderms.

Sea-level rise (SLR) and obstructions to sediment delivery pose challenges to the persistence of estuarine habitats and the ecosystem services they provide. Restoration actions and sediment management strategies may help mitigate such challenges by encouraging the vertical accretion of sediment in and horizontal migration of tidal forests and marshes. We used a process-based soil accretion model (Coastal Wetland Equilibrium Model) combined with a habitat classification model (MOSAICS) to estimate the effects of SLR, suspended sediment, and inland habitat migration on estuarine habitats, soil carbon accumulation, and economic value of climate change mitigation of carbon accumulation (social cost of carbon dioxide) in a macrotidal estuary in the northwest USA over 100 years (2011 to 2110). Under present-day sediment levels, we projected that after 100 years, most high salt marsh would remain with < 100 cm SLR, but substantial area converted to transitional (low) salt marsh and mudflat with ≥ 100 cm SLR. Increasing sediment availability increased the projected resilience of transitional salt marsh to SLR but did not prevent declines in high marsh area. Projected total carbon accumulation plateaued or declined with ≥ 100 cm SLR, yet the economic value of carbon accumulation continued to rise over time, suggesting that the value of this ecosystem service was resilient to SLR. Doubling or tripling sediment availability increased projected carbon accumulation up to 7.69 and 14.2 kg m−2 and increased total economic value up to $373,000 and $710,000, respectively. Allowing marsh migration supported conversion of upland to freshwater marsh, with slight increases in carbon accumulation. These results inform climate adaptation planning for wetland managers seeking to understand the resilience of estuarine habitats and ecosystem services to SLR under multiple management strategies.

Disturbances such as disease can reshape communities through interruption of ecological interactions. Changes to population demographics alter how effectively a species performs its ecological role. While a population may recover in density, this may not translate to recovery of ecological function. In 2013, a sea star wasting syndrome outbreak caused mass mortality of the keystone predator Pisaster ochraceus on the North American Pacific coast. We analyzed sea star counts, biomass, size distributions, and recruitment from long‐term intertidal monitoring sites from San Diego to Alaska to assess regional trends in sea star recovery following the outbreak. Recruitment, an indicator of population recovery, has been spatially patchy and varied within and among regions of the coast. Despite sea star counts approaching predisease numbers, sea star biomass, a measure of predation potential on the mussel Mytilus californianus, has remained low. This indicates that post‐outbreak populations have not regained their full predation pressure. The regional variability in percent of recovering sites suggested differences in factors promoting sea star recovery between regions but did not show consistent patterns in postoutbreak recruitment on a coast‐wide scale. These results shape predictions of where changes in community composition are likely to occur in years following the disease outbreak and provide insight into how populations of keystone species resume their ecological roles following mortality‐inducing disturbances. We analyzed sea star abundance, biomass, size distributions, and arrival dates of sea stars on the North American Pacific coast to assess geographic trends in recovery of a keystone predator following the sea star wasting syndrome outbreak. While sea star abundance is beginning to rebound, biomass, a measure of predation potential, has remained low, indicating that postoutbreak populations have not regained their full predation pressure in many regions of the Pacific coast.

Coastal habitats, such as salt marshes and dune systems, can protect communities from hazards by reducing coastline exposure. However, these critical habitats and their diverse ecosystem services are threatened by coastal development and the impacts from a changing climate. Ever increasing pressure on coastal habitats calls for coastal climate adaptation efforts that mitigate or adapt to these pressures in ways that maintain the integrity of coastal landscapes. An important challenge for decisionmakers is determining the best mitigation and adaptation strategies that not only protect human lives and property, but also safeguard the ability of coastal habitats to provide a broad suite of benefits. Here, we present a potential pathway for local-scale climate change adaptation planning through the identification and mapping of natural habitats that provide the greatest benefits to coastal communities. The methodology coupled a coastal vulnerability model with a climate adaptation policy assessment in an effort to identify priority locations for nature-based solutions that reduce vulnerability of critical assets using feasible land-use policy methods. Our results demonstrate the critical role of natural habitats in providing the ecosystem service of coastal protection in California. We found that specific dune habitats play a key role in reducing erosion and inundation of the coastline and that several wetland areas help to absorb energy from storms and provide a protective service for the coast of Marin county, California, USA. Climate change and adaptation planning are globally relevant issues in which the scalability and transferability of solutions must be considered. This work outlines an iterative approach for climate adaptation planning at a local-scale, with opportunity to consider the scalability of an iterative science-policy engagement approach to regional, national, and international levels.

As the contribution for long-term ecological and environmental studies (LTEES) to our understanding of how species and ecosystems respond to a changing global climate becomes more urgent, the relative number and investment in LTEES are declining. To assess the value of LTEES to advancing the field of ecology, we evaluated relationships between citation rates and study duration, as well as the representation of LTEES with the impact factors of 15 ecological journals. We found that the proportionate representation of LTEES increases with journal impact factor and that the positive relationship between citation rate and study duration is stronger as journal impact factor increases. We also found that the representation of LTEES in reports written to inform policy was greater than their representation in the ecological literature and that their authors particularly valued LTEES. We conclude that the relative investment in LTEES by ecologists and funders should be seriously reconsidered for advancing ecology and its contribution to informing environmental policy.

We used a 12-yr data set of benthic cover (2005–2017), spanning two bleaching events, to assess changes in benthic cover and coral community composition along 21 islands within Gulf of Mannar (GoM), southeast India. Overall, between 2005 and 2017 reefs had a simultaneous decrease in relative coral cover (avg. =  − 36%) and increase in algal cover (avg. =  + 45%). Changes in benthic cover were not consistent among islands, ranging from − 34 to + 5% for coral cover and from − 0.3 to + 50% for algae. There was a spatial gradient in coral mortality, which increased among islands from west to east. However, there was a disconnect between coral loss and subsequent increases in algae. Algal cover increased more on islands in west GoM where coral loss was minimal. Environmental co-factors (coral cover, percent bleaching, degree heating weeks, fish densities, Chl-a, pollution) explained > 50% of the benthic cover responses to successive bleaching. Coral survival was favored on islands with higher fish densities and chlorophyll-a levels, and increases in algal cover were associated with higher measures of pollution from terrestrial runoff. Coral morphotypes differed in their response following successive bleaching resulting in changes in the relative abundance of different coral morphotypes. Existing climate projections (RCP8.5) indicate a 22-yr gap in the onset of annual severe bleaching (ASB) for reefs in the east versus west GoM, and ASB was ameliorated for all reefs under the RCP4.5 projections. There is limited knowledge of the resilience of GoM reefs, and this study identifies coral morphotypes and reefs that are most likely to recover or decline from successive bleaching, in the context of forecasts of the frequency of future bleaching events in GoM.