Divergent driving mechanisms of community temporal stability in China's drylands

Climate change and anthropogenic activities are reshaping dryland ecosystems globally at an unprecedented pace, jeopardizing their stability. The stability of these ecosystems is crucial for maintaining ecological balance and supporting local communities. Yet, the mechanisms governing their stability are poorly understood, largely due to the scarcity of comprehensive field data. Here we show the patterns of community temporal stability and its determinants across an aridity spectrum by integrating a transect survey across China's drylands with remote sensing. Our results revealed a U-shaped relationship between community temporal stability and aridity, with a pivotal shift occurring around an aridity level of 0.88. In less arid areas (aridity level below 0.88), enhanced precipitation and biodiversity were associated with increased community productivity and stability. Conversely, in more arid zones (aridity level above 0.88), elevated soil organic carbon and biodiversity were linked to greater fluctuations in community productivity and reduced stability. Our study identifies a critical aridity threshold that precipitates significant changes in community stability in China's drylands, underscoring the importance of distinct mechanisms driving ecosystem stability in varying aridity contexts. These insights are pivotal for developing informed ecosystem management and policy strategies tailored to the unique challenges of dryland conservation.

Alpine Rhododendron population contractions lead to spatial distribution mismatch with their pollinators under climate change

The effect of global climate change on plant-pollinator interaction is not limited to changes in phenology and richness within communities but also includes the spatial mismatch caused by the inconsistency of geographical distribution changes. Subsequently, the pollinator interaction network may be remodeled or even disrupted. In this study, we simulated the suitable habitat niche of 15 Rhododendron species and their eight pollinator species as well as their overlapping versus geographical mismatch under the current and three future climate change scenarios in 2090s, using MaxEnt. Results showed that the suitable habitat of all Rhododendron species would decrease in 2090s. In particular, 10, 8, and 13 Rhododendron-pollinator assemblages would have a reduced spatial match region under the climate change scenarios, mainly due to the contraction of the suitable habitat of Rhododendron species. The results provide novel insights into the response of plant-pollinator interactions to global warming, useful to prioritize conservation actions of alpine plant ecosystems.

Phytoplankton assemblage responses to nitrogen following COVID-19 stay-in-place orders in western Long Island Sound (New York/Connecticut)

This study evaluated water quality, nitrogen (N), and phytoplankton assemblage linkages along the western Long Island Sound (USA) shoreline (Nov. 2020-Dec. 2021) following COVID-19 stay-in-place (SIP) orders through monthly surveys and N-addition bioassays. Ammonia-N (AmN; NH3+NH4+) negatively correlated with total chlorophyll-a (chl-a) at all sites; this was significant at Alley Creek, adjacent to urban wastewater inputs, and at Calf Pasture, by the Norwalk River (Spearman rank correlation, p < 0.01 and 0.02). Diatoms were abundant throughout the study, though dinoflagellates (Heterocapsa, Prorocentrum), euglenoids/cryptophytes, and both nano- and picoplankton biomass increased during summer. In field and experimental assessments, high nitrite + nitrate (N + N) and low AmN increased diatom abundances while AmN was positively linked to cryptophyte concentrations. Likely N + N decreases with presumably minimal changes in AmN and organic N during COVID-19 SIP resulted in phytoplankton assemblage shifts (decreased diatoms, increased euglenoids/cryptophytes), highlighting the ecological impacts of N-form delivered by wastewater to urban estuaries.

Silvopastoral management for lowering trade-offs between beef production and carbon storage in tropical dry woodlands

Tropical dry woodlands and savannas harbour high levels of biodiversity and carbon, but are also important regions for agricultural production. This generates trade-offs between agriculture and the environment, as agricultural expansion and intensification typically involve the removal of natural woody vegetation. Cattle ranching is an expanding land use in many of these regions, but how different forms of ranching mediate the production/environment trade-off remains weakly understood. Here, we focus on the Argentine Chaco, to evaluate trade-offs between beef production and carbon storage in grazing systems with different levels of woody cover (n = 27). We measured beef productivity and carbon storage during 2018/19 and used a regression framework to quantify the trade-off between both, and to analyze which agroclimatic and management variables explain the observed trade-off. Our main finding was that silvopastures had the lowest trade-off between beef production and carbon storage, as management in these systems seeks to increase herbaceous forage by removing shrubs, while maintaining most of the bigger trees that contain most above-ground carbon. The most important variable explaining the beef production/carbon storage trade-off was pasture management, specifically the number of shrub encroachment control interventions, with a lower trade-off for higher numbers of interventions. Unfortunately, more interventions can also result in woody cover degradation over time, and shrub encroachment management must therefore be improved to become sustainable. Overall, our study highlights the strong environmental trade-offs associated with beef production in dry woodlands and savanna, but also the key role of good management practices in lowering this trade-off. Specifically, silvopastoral systems can increase beef production as much as converting woodlands to tree-less pastures, but silvopastures retain much more carbon in aboveground vegetation. Silvopastoral systems thus represent a promising land-use option to lower production/environment trade-offs in the Dry Chaco and likely many other tropical dry woodlands and savannas.

Evaluating the long term effectiveness of a Mediterranean marine protected area to tackle the effects of invasive and range expanding herbivorous fish on rocky reefs

Here we provide evidence, along an 8-year period time-series based on multifaceted data from a Mediterranean marine protected area (MPA), whether protection can tackle invasive and range expanding herbivore fishes, and their effects on the algal resource availability, taking into account the population trends of predatory fishes, fisheries catches of herbivore fishes and sea surface temperature (SST) through time. Our findings pointed out that an ineffective in restoring top-down control process MPA may facilitate, rather than alleviate, the sudden and enduring population burst of invasive and range-expanding herbivorous fishes at tipping points of abrupt change. This subsequently results in the deterioration of rocky reef habitats and the depletion of algal resources, with the tipping points of abrupt change for algal and herbivore fish species not overlapping chronologically. As sea temperature increases, ineffective or recently established MPAs may inadvertently facilitate the proliferation of invasive and range-expanding species, posing a significant challenge to management effectiveness and conservation objectives.

Habitat sensitivity in the West African coastal area: inferences and implications for regional adaptations to climate change and ocean acidification

This study focuses on assessing coastal vulnerability and habitat sensitivity along the West African coast by delineating hotspots based on surface temperature, pH, chlorophyll-a, particulate organic carbon, and carbonate concentrations between 2018 and 2023 depending on data availability. Initial exploration of these variables revealed two distinct focal points i.e., the Togo-Nigerian coastal stretch and the stretch from Sierra Leone to Mauritania. Lower pH trends (acidification) in surface waters were observed off the West African coast, particularly in areas around the south-south Niger Delta in Nigeria and the coastal regions of Guinea and Guinea Bissau. Sea surface temperature analysis revealed highest temperatures (27-30°C) within Nigeria to Guinea coastal stretch, intermediate temperatures (24-27°C) within the Guinea Bissau and Senegal coastal stretch, and the lowest temperatures off the coast of Mauritania. Furthermore, correlation analysis between sea surface temperature and calcite concentration in the Mauritania-Senegal hotspot, as well as between overland runoff and particulate organic carbon in the Togo-Nigeria hotspot, revealed strong positive associations (r>0.60) and considerable predictive variability (R2 ≈ 0.40). From the habitat sensitivity analysis, certain regions, including Cape Verde, Côte d'Ivoire, Nigeria, Senegal, and Sierra Leone, exhibited high sensitivity due to environmental challenges and strong human dependence on coastal resources. Conversely, Gambia, Guinea, Guinea-Bissau, Liberia, and Togo displayed lower sensitivity, influenced by geographical-related factors (e.g. coastal layout, topography, etc.) and current levels of economic development (relatively lower industrialization levels). Regional pH variations in West African coastal waters have profound implications for ecosystems, fisheries, and communities. Addressing these challenges requires collaborative regional policies to safeguard shared marine resources. These findings underscore the link between ecosystem health, socioeconomics, and the need for integrated coastal management and ongoing research to support effective conservation.

Past and projected future patterns of fractional vegetation coverage in China

With the intensifying climate change and the strengthening ecosystem management, quantifying the past and predicting the future influence of these two factors on vegetation change patterns in China need to be analyzed urgently. By constructing a framework model to accurately identify fractional vegetation coverage (FVC) change patterns, we found that FVC in China from 1982 to 2018 mainly showed linear increase (29.5 %) or Gaussian decrease (27.4 %). FVC variation was mainly affected by soil moisture in the Qi-North region and by vapor pressure deficit in other regions. The influence of environmental change on FVC, except for Yang-Qi region in the southwest (-2.0 %), played a positive role, and weakened from the middle (Hu-Yang region: 2.7 %) to the northwest (Qi-North region: 2.4 %) to the east (Hu-East region: 0.8 %). Based on five machine learning algorithms, it was predicted that under four Shared Socioeconomic Pathways (SSPs, including SSP126、SSP245、SSP370、SSP585) from 2019 to 2060, FVC would maintain an upward trend, except for the east, where FVC would rapidly decline after 2039. FVC in the eastern region experienced a transition from past growth to future decline, suggesting that the focus of future ecosystem management should be on this region.

Assessment of coastal and marine ecosystems in West Africa: The case of Ghana

Coastal and marine ecosystems, as integral component of social, ecological, and economic systems, are critical in providing essential ecosystem services that underpin human activities, including fishing and mining. Effective management of these ecosystems is paramount to safeguarding their vital contributions. This study adopts a socio-ecological framework, "Drivers (D) of human activities (A), associated Pressures (P), State change in coastal and marine environments, Impact (I) on human welfare (W) and Response (R) as measures (M) of management, (DAPSI(W)R(M))," to analyse the complexities of coastal and marine ecosystems in the Ghanaian context. The study identifies various drivers of anthropogenic activities, such as fishing, oil and gas production, and waste disposal. These anthropogenic activities create significant pressures, including selective extraction of living and non-living resources, as well as habitat degradation through substratum loss and pollution. Consequently, these pressures have led to changes in fish biomass and habitat quality, among other ecological shifts.

The composition, distribution, and socio-economic dimensions of Ghana's mangrove ecosystems

Mangrove ecosystems are recognised as one of the nature-based solutions to a changing climate. Notwithstanding the socio-ecological benefits of mangrove ecosystems, they are increasingly being destructed in some regions of the world. In Ghana, several studies have reported on the status, use, and management strategies of mangrove ecosystems in different sites of the country. However, these studies do not make it possible to appreciate the broader picture of Ghana's mangrove ecosystems since they are not synthesized into a single comprehensive report. This study uses the ROSES method for systematic reviews to report on Ghana's mangrove ecosystem distribution and species composition, as well as their socio-economic benefits, the anthropogenic and natural impacts on Ghana's mangrove ecosystems, and the management strategies and/or practices on Ghana's mangrove ecosystems. The study reveals there is no existing management strategy for Ghana's mangrove ecosystems, and therefore recommends the need to develop and implement policies and regulations that specifically target the protection and sustainable use of mangrove ecosystems in Ghana.

Four-decade (1977-2017) landscape tale of tourist reservoir hotspot El Piñol-Guatapé, Colombia

Efficient management of land use/land cover (LULC) features is vital for a balanced sustainable ecosystem. Thus, this work aimed to document the LULC changes in the less studied El Peñol-Guatapé reservoir, Antioquia, Colombia, especially in the reservoir area due to the construction of a hydro-electric power plant. For this study, Landsat images of 1977, 1986, 1997, and 2017 were used and the results indicated an increase in the settlement area and road networks by 0.10 and 0.60%, respectively, while during 1986 to 2017, cropland, plantation, dense forest, and open forest areas presented an increase of 0.52, 1.06, 2.87 and 2.61%, respectively. However, the marshy vegetation, scrub forest and fallow land decreased to - 0.51, - 3.79 and - 4.29%, respectively, in the same period. The water body before and after the completion of reservoir project denoted an increase from 13.1 km² in 1977 to 45.7 km² in 1986. This study provides a first-hand report on LULC dynamics in this tourism dominated municipalities that will serve as a reference for ecosystem management to reconcile the conflicts between different LULC classes in ecologically enriched regions.

Leveraging species richness and ecological condition indices to guide systematic conservation planning

The global crises of biodiversity loss and climate change are interconnected in root cause and solutions. Targeted land conservation has emerged as a leading strategy to protect vulnerable species and buffer climate impacts, however, consistent methods to assess biodiversity and prioritize areas for protection have not yet been established. Recent landscape-scale planning initiatives in California present an opportunity to conserve biodiversity, but to enhance their effectiveness, assessment approaches should move beyond commonly used measures of terrestrial species richness. In this study, we compile publicly available datasets and explore how distinct biodiversity conservation indices - including indicators of terrestrial and aquatic species richness and of biotic and physical ecosystem condition - are represented in watersheds of the northern Sierra Nevada mountain region of California (n = 253). We also evaluate the extent to which the existing protected area network covers watersheds that support high species richness and intact ecosystems. Terrestrial and aquatic species richness showed unique spatial patterns (Spearman R = 0.27), with highest richness of aquatic species in the low-elevation watersheds of the study area and highest richness of terrestrial species in mid- and high-elevation watersheds. Watersheds with the highest ecosystem condition were concentrated in upper-elevations and were poorly correlated with those with the highest species richness (Spearman R = -0.34). We found that 28% of watersheds in the study area are conserved by the existing protected area network. Protected watersheds had higher ecosystem condition (mean rank-normalized score = 0.71) than unprotected areas (0.42), but species richness was generally lower (0.33 in protected versus 0.57 in unprotected watersheds). We illustrate how the complementary measures of species richness and ecosystem condition can be used to guide strategies for landscape-scale ecosystem management, including prioritization of watersheds for targeted protection, restoration, monitoring, and multi-benefit management. Though designed for California, application of these indices to guide conservation planning, design monitoring networks, and implement landscape-scale management interventions provides a model for other regions of the world.

Evaluation of the potential stranding risk for aquatic organisms according to long-term morphological changes and grain size in alpine rivers impacted by hydropeaking

Hydropeaking is one of the major hydropower-related disturbances of natural processes in river systems. The artificial flow fluctuations that are caused by the on-demand production of electricity are known for their severe impacts on aquatic ecosystems. These particularly affect those species and life stages that are not able to adjust their habitat selection to rapid up- and downramping rates. To date, the stranding risk has both experimentally and numerically mainly been investigated with variable hydropeaking graphs over stable river bathymetries. There is a lack of knowledge on how single, discrete peaking events vary concerning their impact on the stranding risk when the river morphology changes in the long-term perspective. The present study precisely addresses this knowledge gap by investigating morphological changes on the reach scale over a period of 20 years and the related variability of the lateral ramping velocity as a proxy for stranding risk. Two alpine gravel bed rivers impacted by hydropeaking over decades were tested by applying a one-dimensional and two-dimensional unsteady modelling approach. Both the Bregenzerach River and the Inn River exhibit alternating gravel bars on the reach scale. The results of the morphological development, however, showed different developments in the period 1995-2015. The Bregenzerach River displayed continuous aggradation (uplift of river bed) over the various selected submonitoring periods. In contrast, the Inn River showed continuous incision (erosion of river bed). The stranding risk exhibited high variability on a single cross-sectional basis. However, on the reach scale, no significant changes in stranding risk were calculated for either river reach. In addition, the impacts of river incision on the substrate composition were investigated. Here, in line with preceding studies, the results show that the coarsening of substrate increases the stranding risk and that especially the d₉₀ (90 % finer of the grain size distribution) must be considered. The present study reveals that the quantified stranding risk of aquatic organisms is a function of the general morphological (bar) characteristics of the impacted river and both the morphological and grain size development have an impact on the potential stranding risk of aquatic organisms and should be considered in the revision of licences in the management of multi-stressed river systems.

An exhaustive evaluation of modeling ecological niches above species level to predict marine biological invasions

Identifying the areas of the world with suitable environmental conditions for the establishment of invasive species represents a fundamental basis for preventing their impacts. One of the most widely used tools for this is ecological niche modeling. Nonetheless, this approach may underestimate the specie's physiological tolerances (it's potential niche) since wildlife populations of species usually do not occupy their entire environmental tolerance. Recently, it has been suggested that incorporating occurrences of phylogenetically related species improves the prediction of biological invasions. However, the reproducibility of this technique remains unclear. Here, we evaluated the generality of this protocol by assessing whether the construction of modeling units above species level improves the capacity of niche models to predict the distribution of 26 target marine invasive species. For each, we constructed supraspecific modeling units based on published phylogenies by grouping the native occurrence records of each invasive species with the records of its phylogenetically closest relative. We also considered units at species level, including only the presence of records in the native areas of the target species. We generated ecological niche models for each unit with three modeling methods (minimum volume ellipsoids - MVE, machine learning algorithms - Maxent and a presence-absence method - GLM). In addition, we grouped the 26 target species based on whether or not the species are in environmental pseudo-equilibrium (i.e., it occupies all habitats where it can disperse) and have any geographical or biological constraints. Our results suggest that the construction of supraspecific units improves the predictive capacity of correlative models to estimate the invasion area of our target species. This modeling approach consistently generated models with a higher predictive ability for species in non-environmental pseudo-equilibrium and with geographical constraints.

The social-ecological system of the Kenai River Fishery (Alaska, USA)

We present a collaboratively developed social-ecological model of the Kenai River Fishery. We developed the model through iterative interviews with stakeholders throughout the Kenai Peninsula using a novel participatory Fuzzy Cognitive Mapping process grounded in Ostrom's social-ecological systems framework. Individual social-ecological models, developed one-on-one with stakeholders, were combined into a single aggregated model representing the system's structure and function. We validated this aggregated model through subsequent interviews with stakeholders and focused literature reviews. The result is a model that can: 1) illustrate the breadth and interconnectedness of the Kenai River Fishery's social-ecological system; 2) be used to facilitate discussions around management of the fishery; and 3) be used to explore the components and interactions that move the system toward or away from sustainability. Using the model, we identify how the nature of salmon (migratory) and their habitat (large and unpredictable) leads to uncertainty about effective management strategies. This uncertainty, in addition to a large and diverse set of resource users, creates conflicting management goals that ultimately limit the governance system in making decisions that might increase the sustainability of the fishery.

Climate Change and Variability Impacts on Agricultural Production and Food Security for the Smallholder Farmers in Rungwe, Tanzania

Climate change and variability pose serious challenges among smallholder farmers in developing countries. Low adaptive capacity aggravates the challenges to farming activities and ecosystem management. This study employed survey methods to assess the implications of climate variability and environmental changes in agricultural production and food security. The study used different research methods, including literature review, participatory rural appraisal, household questionnaire, key informant interview and field observation for data collection. The data collected were organised, triangulated, synthesised, processed, analysed using thematic and trend analyses for qualitative data and Microsoft Excel and SPSS 20 software programme manipulation for quantitative data. Severe and frequent climatic extremes that include drought, heavy rainfall, temperature variations, and strong winds are smallholder farmers' main challenges in production. As a result, the production trends and productivity of the main rainfed crops decreased significantly. The duration of the growing season also decreased, negatively affecting the local food supplies. The statistical results signify a robust negative correlation between climate variability and the production of the leading food crops (X² = 6.00 with p = 0.199 and X² = 10.00 with p = 0.350). In addressing the challenges, improving farming practices such as crop diversification and improved extension services were suggested. However, such options would require appropriate environmentally friendly technologies in an enabling environment both locally and nationally.

Effects of habitat fragmentation on the recruitment and early post-settlement survival of coral reef fishes

The combined effects of global climate change and local anthropogenic stressors are leading to increasing loss and fragmentation of habitats. On coral reefs, habitat loss has been shown to influence the abundance and composition of associated fish assemblages, yet few studies have considered how habitat fragmentation may influence reef fish populations and assemblages. Herein, we compared survival, growth and recruitment of reef fish among experimental patches composed of six similar sized colonies of finely branching Pocillopora spp. but with different degrees of fragmentation: coral colonies were clumped (unfragmented), divided into two groups (low fragmentation), three groups (moderate fragmentation) or six groups (high fragmentation). Thirty settlement-stage Pomacentrus amboinensis were tagged, released onto each of the experimental patches, and their survival monitored daily for 11 days. Abundance and species richness of all reef fishes that subsequently recruited to the patches were also recorded, and used to analyse recruitment and community composition. There were no detectable differences among fragmentation treatments in the abundance or composition of reef fish assemblages that recruited to the patches, however, fragmentation influenced the survivorship of P. amboinensis. Highest survival of P. amboinensis was recorded on the unfragmented patches (61%.11 days^-1) and highly fragmented habitat patches (54%.11 days^-1) and lowest survival on low and moderate fragmentation treatments (47% and 48%.11 days^-1, respectively). This suggests that there may be multiple competing processes that moderate mortality (e.g., predation) in unfragmented versus highly fragmented habitats, with moderate levels of habitat fragmentation having the greatest influence on the early post-settlement survival of corsal reef fish.

Are stable isotopes an efficient tool for tracking the effect of anthropogenic activities on mangrove food web structure and function?

Understanding and connecting the impact of anthropogenic activities on mangrove food webs is a research challenge. Has research on the subject been able to find answers using stable isotopes? The present opinion paper analyzed the utility of stable isotopes in tracing the impact of anthropogenic activities on mangrove food webs and if the research questions raised could be answered using these chemical markers. Representative research papers (16) focused on the use of stable isotopes (δ¹³C, δ¹⁵N, δ³⁴S, δ²H, δD,206Pb/207Pb, and 208Pb/207Pb) to evaluate the effect of anthropogenic activities (Sewage discharge, timber harvesting-deforestation, metallurgical activities, hydrological disruption, aquaculture ponds, and urban development) on mangrove food webs were selected. Each article included at least one group of consumers (invertebrate or fish). Publications only focused on water quality or primary producers were not included. Most studies managed to determine the effect of the anthropogenic activities on the food web's stable isotope values. Based on the above, we concluded that these markers are an effective tool to determine affectation patterns on the structure and function of mangrove food webs. The results obtained herein facilitate the correct management of mangroves and their derived resources.

A review of the knowledge of reef fish in the Southwest Atlantic

Reef environments are rapidly transforming worldwide, and these changes are causing major impacts to the reef ecosystem. Scientific knowledge is strategic for marine conservation and management in these scenarios. Aiming to contribute to this subject, a systematic review from 1967 to 2020 was conducted, in order to identify gaps in studies regarding reef fish species, ecosystem components and processes. Multidisciplinary sciences concerning reef fish have been rising, mainly in the fields of basic biology and ecology. Besides that, phase shifts and ecosystem services were absent terms in the analyzes of co-occurrence. Research in the ethnosciences needs to be increased, and will improve access to local ecological knowledge, which can be used as a tool to address issues in reef environments. Socio-ecological systems are components of this landscape that has had few publications. The participation in the elaboration of public policies can be a new avenue to foster the biodiversity of reef environments.

Long-term monitoring projects of Brazilian marine and coastal ecosystems

Biodiversity assessment is a mandatory task for sustainable and adaptive management for the next decade, and long-term ecological monitoring programs are a cornerstone for understanding changes in ecosystems. The Brazilian Long-Term Ecological Research Program (PELD) is an integrated effort model supported by public funds that finance ecological studies at 34 locations. By interviewing and compiling data from project coordinators, we assessed monitoring efforts, targeting biological groups and scientific production from nine PELD projects encompassing coastal lagoons to mesophotic reefs and oceanic islands. Reef environments and fish groups were the most often studied within the long-term projects. PELD projects covered priority areas for conservation but missed sensitive areas close to large cities, as well as underrepresenting ecosystems on the North and Northeast Brazilian coast. Long-term monitoring projects in marine and coastal environments in Brazil are recent (<5 years), not yet integrated as a network, but scientifically productive with considerable relevance for academic and human resources training. Scientific production increased exponentially with project age, despite interruption and shortage of funding during their history. From our diagnosis, we recommend some actions to fill in observed gaps, such as: enhancing projects' collaboration and integration; focusing on priority regions for new projects; broadening the scope of monitored variables; and, maintenance of funding for existing projects.

Benthic ecosystem functioning under climate change: modelling the bioturbation potential for benthic key species in the southern North Sea

Climate change affects the marine environment on many levels with profound consequences for numerous biological, chemical, and physical processes. Benthic bioturbation is one of the most relevant and significant processes for benthic-pelagic coupling and biogeochemical fluxes in marine sediments, such as the uptake, transport, and remineralisation of organic carbon. However, only little is known about how climate change affects the distribution and intensity of benthic bioturbation of a shallow temperate shelf sea system such as the southern North Sea. In this study, we modelled and projected changes in bioturbation potential (BP_p) under a continuous global warming scenario for seven southern North Sea key bioturbators: Abra alba, Amphiura filiformis, Callianassa subterranea, Echinocardium cordatum, Goniada maculata, Nephtys hombergii, and Nucula nitidosa. Spatial changes in species bioturbation intensity are simulated for the years 2050 and 2099 based on one species distribution model per species driven by bottom temperature and salinity changes using the IPCC SRES scenario A1B. Local mean bottom temperature was projected to increase between 0.15 and 5.4 °C, while mean bottom salinity was projected to moderately decrease by 1.7. Our results show that the considered benthic species are strongly influenced by the temperature increase. Although the total BP remained rather constant in the southern North Sea, the BP_p for four out of seven species was projected to increase, mainly due to a simultaneous northward range expansion, while the BP_p in the core area of the southern North Sea declined for the same species. Bioturbation of the most important species, Amphiura filiformis and Echinocardium cordatum, showed no substantial change in the spatial distribution, but over time. The BP_p of E. cordatum remained almost constant until 2099, while the BP_p of A. filiformis decreased by 41%. The northward expansion of some species and the decline of most species in the south led to a change of relative contribution to bioturbation in the southern North Sea. These results indicate that some of the selected key bioturbators in the southern North Sea might partly compensate the decrease in bioturbation by others. But especially in the depositional areas where bioturbation plays a specifically important role for ecosystem functioning, bioturbation potential declined until 2099, which might affect the biochemical cycling in sediments of some areas of the southern North Sea.

A conceptual approach to characterizing ecological suitability: Informing socio-ecological measures for restoration effectiveness

A combination of ecological and socio-economic outcome indicators is essential for understanding and assessing the effectiveness of the remediation and restoration of degraded ecosystems and revitalizing communities that could benefit from these ecosystem management activities. In this paper, we propose and develop a conceptual approach to characterize ecological suitability that incorporates ecological attributes that support ecosystem structural diversity and functionality, stakeholder values and perceptions, and the benefits derived from ecosystem goods and services. A structured literature review was used to identify existing restoration frameworks and indicators to inform the conceptual foundation for characterizing ecological suitability. The structure of the conceptual approach primarily builds from ecological and social attributes in the International Principles and Standards for the Practice of Ecological Restoration (Gann et al., 2019). We provide a conceptual example of the ecological suitability approach in estuaries. This example is based on habitat suitability and food web characterizations in combination with the provisioning of ecosystem services and desired social benefits to prioritize and evaluate restoration effectiveness. This foundational work sets the stage for developing a composite measure of ecological suitability. The holistic conceptual approach presented complements existing information regarding restoration effectiveness evaluations. Characterizing ecological suitability is a novel way to incorporate ecological and social information and communicate potential restoration outcomes to ecosystem managers and stakeholders.

A critical evaluation of benthic phase shift studies on coral reefs

Coral reef decline has accelerated in the last two decades resulting in substantial research into the phenomenon of 'phase shifts' or 'regime shifts'. However, the conclusions drawn from this research have been varied. Some of this variability may stem from methodological approaches, although the extent to which these factors have shaped our understanding remain largely unexplored. To examine this, we conducted a systematic review of the literature. In doing so, we revealed marked variability in the approaches used for studying phase shifts. Notably, very few studies clearly defined what they meant by phase shifts. Therefore, we developed a clarified definition of phase shifts, which specifically defined persistence and dominance. The applicability of this definition was tested on multi-decadal benthic composition data on the Great Barrier Reef. The number of shifts depended critically on the definition selected, suggesting that this may be a primary reason underpinning the variability in past results.

An evolving marine environment and its driving forces of algal blooms in the Southern Yellow Sea of China

Continuing global warming and intensification of human activities have substantially disturbed the balance of coastal marine ecosystems, potentially creating favorable conditions for algal blooms. Using serial remote sensing data and various national and provincial statistics, we investigated the spatial and temporal variations of the environmental driving forces for algal blooms in the Southern Yellow Sea between 2003 and 2017. The findings suggest that (1) Continual warming was observed in the Southern Yellow Sea. The study area evidenced more than three times the warming speed (0.41 °C/decade) of the global oceans (0.12 °C/decade) during the same period. There was an apparent warming zone in the region where macroalgal blooms tended to spread, with a heating of 1.0-1.5 °C (May-June). (2) Nutrient loadings have diverse patterns, characterized by fast-growing aquaculture activities and declining nutrients from land-based agriculture fertilizers and sewage discharge (based on published national and provincial statistics). (3) Growing expansion of algal blooms in the Southern Yellow Sea was confirmed by the relative increases in average May-June chlorophyll-a concentration of 46.7% and floating biomass area from 3.3% in 2003 to 13.4% in 2017. (4) While spatial correlation analysis showed a positive influence of the ocean surface temperature on chlorophyll-a, their relatively moderate (r = 0.40, p < 0.15) and declining correlations suggest that nutrient enrichment could be comparatively more influential on macroalgal blooms. Nutrient loading from the discharge of wastewater sourced from coastal aquaculture and organic residuals from land-sourcing sewage and industrial pollution, even though declining as reported, is still upholding a high level of nutrient enrichment in the study area. In addition, the fixed facilities for seaweed mariculture in the region provide vast breeding surfaces for algae. Consequently, the Southern Yellow Sea has become an ideal marine area for algal blooms.

Bioaccumulation of trace metals in two oyster species from southwest Puerto Rico

As coastal ecosystems are impacted by land use change and anthropogenic activities, oysters can be an important tool for monitoring local water quality. We collected oysters (Crassostrea rhizophorae and Isognomon alatus) from coastal sites near Guánica and La Parguera in southwest Puerto Rico and analyzed their tissue for concentrations of Ag, As, Cd, Co, Cr, Cu, Ni, Pb, V, and Zn. All trace metals were found in both species, with high bioaccumulation factors for Ag, Cd, and Zn in both species and Cr in C. rhizophorae. Some trace metals are likely associated with anthropogenic sources, including paints and vehicles (Cu and Zn), oil (Ni and V), and wood preservatives (As). Cr in oysters near Guánica is most likely associated with sediment from erosion in the watershed. Both species could be used to monitor changes in trace metal concentrations and the influence of future watershed management strategies in the region.

Invasive species services-disservices conundrum: A case study from Kashmir Himalaya

Invasive species and their management represent a multi-faceted issue affecting social and natural systems. People see the advantages and risks of these species through various value structures, which influences decisions on whether and where they can be managed. While many studies have focused on the ecological effects of invasive species, their impact on human livelihoods and well-being is less recognized. Understanding the effects (benefits and costs) of invasive species on livelihoods and human well-being, as well as people's perception, is important for guiding policy formulation and devising management strategies. Here we present a case study of Dal Lake - a freshwater urban lake of Kashmir Himalaya - providing various ecological, biological, and hydrological functions that offer economic, aesthetic, recreational, educational, and other values to the local populace. In the context of a gradually increasing attention on the impacts of Invasive Alien Plant species (IAPs) on this ecosystem, we conducted Focal Group Discussions (FGDs) to determine the perception of people living inside and around Dal Lake regarding two invasive species, namely, Nymphea mexicana and Hydrocharis dubia, and their capacity to provide ecosystem services (ES) and disservices (EDS). Following that, a discursive scenario assessment tool multi-criteria mapping (MCM) was used to involve stakeholders in ranking their priorities in two scenarios of the lake- 'status quo' vs 'clean lake with limited weeds' in the Dal Lake social-ecological system. We found that their perception of the impact of invasive species varies with factors such as the location of invasive plants in the lake, and people's occupation, and household characteristics. Most participants perceive these species positively (i.e., agreeing that they create ecosystem services in the form of cattle feed), but some recognize their importance in providing ecosystem disservices. Their primary concern and priority were the sustenance of their livelihood in any scenario, and most respondents did not oppose the eradication of two IAPs if their livelihood is secure. We conclude that a more nuanced strategy to IAS management is required, one that combines both local livelihood demands and broader environmental and social considerations.

Size-weight relationships for estimating harvestable biomass of Acropora corals on Australia's Great Barrier Reef

Although hard corals (order Scleractinia) are listed in Appendix II of the Convention for the International Trade in Endangered Species (CITES), there is significant ongoing wild harvest and international trade, mostly for the aquarium industry. Acropora corals account for the majority of aquarium corals harvested and traded, but are also extremely vulnerable to fisheries-independent threats, especially climate-induced coral bleaching. Reconciling effects of coral harvesting is complicated as harvest limits are based on weight, while there is limited data on standing biomass of Acropora from different reef environments. Here, a management-friendly methodology that allows for quantification of Acropora spp. biomass is described and demonstrated, thus providing means for the development and implementation of a rigorous sustainable harvest strategy. We establish size-weight relationships for four growth forms of Acropora spp. harvested from Australia's Great Barrier Reef, to facilitate estimates of harvestable biomass and better understand the ecological context of current weight-based harvest levels and limits. Using these relationships, and field-based sampling at 12 sites across seven distinct reefs, the estimated biomass of Acropora spp. ranges from 0.12 kg ⋅ m^-2 to 4.7 kg ⋅ m^-2. These estimates necessitate further consideration of catch composition and the specific abundance of individual species that are heavily harvested, and how impacts of current harvest practices interact with species-specific vulnerability to climate change and other escalating human pressures contributing to the degradation of coral reef ecosystems. This study is a crucial first step towards quantifying the ecological impacts of the fishery to develop management strategies that are underpinned by research.

Safeguarding marine life: conservation of biodiversity and ecosystems

Marine ecosystems and their associated biodiversity sustain life on Earth and hold intrinsic value. Critical marine ecosystem services include maintenance of global oxygen and carbon cycles, production of food and energy, and sustenance of human wellbeing. However marine ecosystems are swiftly being degraded due to the unsustainable use of marine environments and a rapidly changing climate. The fundamental challenge for the future is therefore to safeguard marine ecosystem biodiversity, function, and adaptive capacity whilst continuing to provide vital resources for the global population. Here, we use foresighting/hindcasting to consider two plausible futures towards 2030: a business-as-usual trajectory (i.e. continuation of current trends), and a more sustainable but technically achievable future in line with the UN Sustainable Development Goals. We identify key drivers that differentiate these alternative futures and use these to develop an action pathway towards the desirable, more sustainable future. Key to achieving the more sustainable future will be establishing integrative (i.e. across jurisdictions and sectors), adaptive management that supports equitable and sustainable stewardship of marine environments. Conserving marine ecosystems will require recalibrating our social, financial, and industrial relationships with the marine environment. While a sustainable future requires long-term planning and commitment beyond 2030, immediate action is needed to avoid tipping points and avert trajectories of ecosystem decline. By acting now to optimise management and protection of marine ecosystems, building upon existing technologies, and conserving the remaining biodiversity, we can create the best opportunity for a sustainable future in 2030 and beyond.

Safeguarding marine life: conservation of biodiversity and ecosystems

Marine ecosystems and their associated biodiversity sustain life on Earth and hold intrinsic value. Critical marine ecosystem services include maintenance of global oxygen and carbon cycles, production of food and energy, and sustenance of human wellbeing. However marine ecosystems are swiftly being degraded due to the unsustainable use of marine environments and a rapidly changing climate. The fundamental challenge for the future is therefore to safeguard marine ecosystem biodiversity, function, and adaptive capacity whilst continuing to provide vital resources for the global population. Here, we use foresighting/hindcasting to consider two plausible futures towards 2030: a business-as-usual trajectory (i.e. continuation of current trends), and a more sustainable but technically achievable future in line with the UN Sustainable Development Goals. We identify key drivers that differentiate these alternative futures and use these to develop an action pathway towards the desirable, more sustainable future. Key to achieving the more sustainable future will be establishing integrative (i.e. across jurisdictions and sectors), adaptive management that supports equitable and sustainable stewardship of marine environments. Conserving marine ecosystems will require recalibrating our social, financial, and industrial relationships with the marine environment. While a sustainable future requires long-term planning and commitment beyond 2030, immediate action is needed to avoid tipping points and avert trajectories of ecosystem decline. By acting now to optimise management and protection of marine ecosystems, building upon existing technologies, and conserving the remaining biodiversity, we can create the best opportunity for a sustainable future in 2030 and beyond.

Collapsing ecosystem functions on an inshore coral reef

Ecosystem functions underpin productivity and key services to humans, such as food provision. However, as the severity of environmental stressors intensifies, it is becoming increasingly unclear if, and to what extent, critical functions and services can be sustained. This issue is epitomised on coral reefs, an ecosystem at the forefront of environmental transitions. We provide a functional profile of a coral reef ecosystem, linking time-series data to quantified processes. The data reveal a prolonged collapse of ecosystem functions in this previously resilient system. The results suggest that sediment accumulation in algal turfs has led to a decline in resource yields to herbivorous fishes and a decrease in fish-based ecosystem functions, including a collapse of both fish biomass and productivity. Unfortunately, at present, algal turf sediment accumulation is rarely monitored nor managed in coral reef systems. Our examination of functions through time highlights the value of directly assessing functions, their potential vulnerability, and the capacity of algal turf sediments to overwhelm productive high-diversity coral reef ecosystems.

Objective indicators contribute more than subjective beliefs to resident willingness to pay for ecosystem services on the Tibetan Plateau

Effective ecosystem management on the Tibetan Plateau will contribute to regional environmental sustainability, and these efforts need broad public support, especially that of residents, over the long run. Although residents' subjective perceptions often directly influence practices, the interactive effects of subjective and objective indicators at the individual level often interfere with resident participation in ecosystem management. With the objective of decoupling the effects of multiple variables on resident participation in environmental sustainability, we launched a questionnaire survey on the topic of willingness to pay (WTP) on the Tibetan Plateau, and explored the effects of single variables and pairwise variables on WTP via dummy regression and proposed specific management suggestions. The results showed that objective indicators were the key drivers of WTP. First, it not only had strong direct effects on WTP (2770.32 CNY/year) but also interacted with subjective beliefs (3805.92 CNY/year); second, it had indirect effects on participation attitudes (R = 0.79) through subjective beliefs (R = 0.38). Put differently, the challenge of achieving sustainable management in the TP is how to enhance and satisfy the sociodemographic and socio-economic attributes of indigenous residents.

Integrating vegetation suitability in sustainable revegetation for the Loess Plateau, China

Revegetation is accelerating globally due to its benefits for ecosystem restoration, desertification prevention, and climate change mitigation. The Loess Plateau has suffered serious erosion in the past decades, and revegetation projects, such as those under the 'Grain for Green' program, have been conducted for soil erosion prevention. The irrational distribution of artificial plantations had negative consequences, including vegetation degradation, soil drying, and decreases in streamflow. Determining the suitable plant species is critical in guiding the design of revegetation programs and may help delimit the suitable boundaries for artificial plantations. In this study, we used an eco-hydrological model to quantify the suitability of two typical revegetation species (Robinia pseudoacacia and Stipa bungeana) using a developed vegetation suitability equation, which estimates the water use/water stress trade-off. The results showed that R. pseudoacacia was more sensitive to water stress than S. bungeana. The water use of both species varied along the precipitation gradient, and S. bungeana generally had a higher water use than R. pseudoacacia. Suitable areas for R. pseudoacacia were mainly located in the northeastern part of the plateau. By overlaying the suitable boundaries for R. pseudoacacia on the current land cover, we found that the area of forests distributed in unsuitable regions reached 7.31% of the entire Loess Plateau. Converting forests beyond the suitable boundary to grasslands would increase the water yield (0.51%-12.23%) and slightly decrease the soil retention capacity (0.01%-0.08%), resulting in a 'win-win' situation for sustainable plant-soil ecosystems and soil-water conservations. Additionally, the suitable area of R. pseudoacacia is predicted to shrink under projected future drying trends. In conclusion, vegetation suitability in the future planning and design of revegetation projects should be considered to effectively tackle the impacts of environmental degradation and climate change in the Loess Plateau.

Towards Building a Sustainable Future: Positioning Ecological Modelling for Impact in Ecosystems Management

As many ecosystems worldwide are in peril, efforts to manage them sustainably require scientific advice. While numerous researchers around the world use a great variety of models to understand ecological dynamics and their responses to disturbances, only a small fraction of these models are ever used to inform ecosystem management. There seems to be a perception that ecological models are not useful for management, even though mathematical models are indispensable in many other fields. We were curious about this mismatch, its roots, and potential ways to overcome it. We searched the literature on recommendations and best practices for how to make ecological models useful to the management of ecosystems and we searched for 'success stories' from the past. We selected and examined several cases where models were instrumental in ecosystem management. We documented their success and asked whether and to what extent they followed recommended best practices. We found that there is not a unique way to conduct a research project that is useful in management decisions. While research is more likely to have impact when conducted with many stakeholders involved and specific to a situation for which data are available, there are great examples of small groups or individuals conducting highly influential research even in the absence of detailed data. We put the question of modelling for ecosystem management into a socio-economic and national context and give our perspectives on how the discipline could move forward.

Climate change effects on marine protected areas: Projected decline of benthic species in the North Sea

Climate change is a global threat for marine ecosystems, their biodiversity and consequently ecosystem services. In the marine realm, marine protected areas (MPAs) were designated to counteract regional pressures, but they might be ineffective to protect vulnerable species and habitats, if their distribution is affected by global climate change. We used six Species Distribution Models (GLM, MARS, FDA, RF, GBM, MAXENT) to project changes in the distribution of eight benthic indicator and key species under climate change in the North Sea MPAs for 2050 and 2099. The projected distribution area of most species will be stable or even increase within the MPAs between 2001 and 2050. Thereafter, the distribution area decreased, especially within MPAs in the central North Sea by 2099, and some key species even disappeared from the MPAs. Consequently, the monitoring and protection of benthic species might not be possible within static MPA borders under climate change.

Information sharing may impede the success of environmental projects

A major challenge in ecosystem management is to promote cooperation among the multiple agents that manage the ecosystem. In particular, sharing information among the agents is often essential for reaching a desirable collective treatment. However, it is unclear how the sharing of information affects the incentives of selfish agents to cooperate and contribute to the common environmental project. Here, we consider a harmful species population that migrates across lands and causes damages to multiple agents, each of which aims to minimize her/his own costs due to both treatment and damages over time. We use game-theoretical models and compare the resulting collective treatment in three scenarios that differ in the information that agents have about (1) the true contribution of their neighbors to the treatment and (2) the true damages inflicted on their neighbors by the harmful species. We demonstrate that sharing such social information may incentivize the agents to free ride on their neighbors' contributions, thereby reducing the efficiency of the collective treatment. This implies that monitoring and sharing information may have negative consequences, and the extent to which information should be shared in joint projects necessitates a careful examination.

Algal turf sediments limit the spatial extent of function delivery on coral reefs

The presence of key organisms is frequently associated with the delivery of specific ecosystem functions. Areas with such organisms are therefore often considered to have greater levels of these functions. While this assumption has been the backbone of coral reef ecosystem-based management approaches for decades, we currently have only a limited understanding of how fish presence equates to function on coral reefs and whether this relationship is susceptible to stressors. To assess the capacity of a stressor to shape function delivery we used a multi-scale approach ranging from tens of kilometres across the continental shelf of Australia's Great Barrier Reef, down to centimetres within a reef habitat. At each scale, we quantified the spatial extent of a model function (detritivory) by a coral reef surgeonfish (Ctenochaetus striatus) and its potential to be shaped by sediments. At broad spatial scales, C. striatus presence was correlated strongly with algal turf sediment loads, while at smaller spatial scales, function delivery appears to be constrained by algal turf sediment distributions. In all cases, sediment loads above ~250-500 g m^-2 were associated with a marked decrease in fish abundance or feeding activity, suggesting that a common ecological threshold lies within this range. Our results reveal a complex functional dynamic between proximate agents of function delivery (fish) and the ultimate drivers of function delivery (sediments), which emphasizes: a) weaknesses in the assumed links between fish presence and function, and b) the multi-scale capacity of algal turf sediments to shape reef processes. Unless direct extractive activities (e.g. fishing) are the main driver of function loss on coral reefs, managing to conserve fish abundance is unlikely to yield the desired outcomes. It only addresses one potential driver. Instead, management of both the agents that deliver functions (e.g. fishes), and the drivers that modify functions (e.g. sediments), is needed.

Electric and magnetic senses in marine animals, and potential behavioral effects of electromagnetic surveys

Electromagnetic surveys generate electromagnetic fields to map petroleum deposits under the seabed with unknown consequences for marine animals. The electric and magnetic fields induced by electromagnetic surveys can be detected by many marine animals, and the generated fields may potentially affect the behavior of perceptive animals. Animals using magnetic cues for migration or local orientation, especially during a restricted time-window, risk being affected by electromagnetic surveys. In electrosensitive animals, anthropogenic electric fields could disrupt a range of behaviors. The lack of studies on effects of the electromagnetic fields induced by electromagnetic surveys on the behavior of magneto- and electrosensitive animals is a reason for concern. Here, we review the use of electric and magnetic fields among marine animals, present data on survey generated and natural electromagnetic fields, and discuss potential effects of electromagnetic surveys on the behavior of marine animals.

Representation of biodiversity and ecosystem services in East Africa's protected area network

The dramatic increase in anthropogenic activity severely threatens the biodiversity and life-support services that underpin human well-being. The broadened focus of protecting ecosystem services (ESs) better aligns the interests of people and biodiversity conservation. In this study, we used species richness as a surrogate for biodiversity and mapped the key ESs in East Africa with the goal to assess the spatial congruence between biodiversity and ESs, and evaluate the representation of current protected areas (PAs) network for biodiversity and ESs. The results showed that PAs well represented for species richness and regulating services but underrepresented for provisioning services. The PAs network occupies 10.96% of East Africa's land surface, and captures 20.62-26.37% of conservation priorities for vertebrate and plant species. It encompasses more than 16.23% of priority areas for three regulating services, but only 6.17% and 5.22% for crop and livestock production, respectively. Strong correlations and high overlaps exist between species richness and regulating services, particularly for carbon storage, water yield and plants. Thus, we believe that actions taken to conserve biodiversity also will protect certain ESs, which in turn will create new incentives and funding sources for the conservation of biodiversity. Overall, our results have wide-ranging policy implications and can be used to optimize conservation strategies for both biodiversity and multiple ESs in East Africa.

Analyzing the effects of various forest management strategies and carbon prices on carbon dynamics in western Turkey

Determining appropriate management strategies to reduce greenhouse gas emissions using optimization techniques to understand how forest management activities affect the carbon dynamics is critical in implementing effective carbon management policies. This paper quantitatively analyzes the long-term effects of different management policies and silvicultural interventions using linear programming. In the analyses, afforestation targets for bare forest lands, tree species, carbon prices, planning approaches and sets of various targets and constraints on carbon dynamics were evaluated. The results were based on twenty-five forest management scenarios formulated for the Korucu Forest Planning Unit of Turkey. The results showed that, compared to timber-based planning strategies (TM), ecosystem-based planning approach (EM) contributes to a significant reduction in carbon sequestration in many cases. When different afforestation targets were incorporated into forest management strategies, cumulative carbon sequestration increased constantly compared to baseline scenario without any afforestation areas. In addition, the highest total carbon sequestration was observed when black pine (P. nigra) was used in afforestation activities rather than oak species (Quercus sp.) and other available tree species. While total timber production and timber net present value (NPV) decreased, carbon sequestration increased significantly with increasing carbon price. As a result of increasing carbon price from $20/ton to $100/ton, joint NPV increased by about five times. The results highlighted the importance of forest ecosystem and developing and implementing climate adaption measures into forest management activities in tackling climate change phenomenon.

Landscape beauty: A wicked problem in sustainable ecosystem management?

Recent discourses on sustainable ecosystem management have increasingly emphasized the importance of bundling relationships and interactions among multiple ecosystem services supported by similar natural and anthropogenic mechanisms within the total environment. Yet, the aesthetic benefits of ecosystems, playing critical role in management of both wild and anthropogenic landscapes, have been under-represented in these discussions. This disregard contributes to the disconnection between environmental science and practice and limits our understanding of ecological and societal implications of management decisions that either generate aesthetic benefits or impact them while targeting other ecosystem services. This discussion reviews several "wicked problems" that arise due to such limited understanding, focusing on three recognized challenges in present-day ecosystem management: replacement of natural ecosystem functions, spatial decoupling of service beneficiaries from its environmental consequences and increasing inequalities in access to services. Strategies towards solutions to such wicked challenges are also discussed, capitalizing on the potential of innovative landscape design, cross-disciplinary research and collaboration, and emerging economic and policy instruments.

Physiological and gene transcription assays to assess responses of mussels to environmental changes

Coastal regions worldwide face increasing management concerns due to natural and anthropogenic forces that have the potential to significantly degrade nearshore marine resources. The goal of our study was to develop and test a monitoring strategy for nearshore marine ecosystems in remote areas that are not readily accessible for sampling. Mussel species have been used extensively to assess ecosystem vulnerability to multiple, interacting stressors. We sampled bay mussels (Mytilus trossulus) in 2015 and 2016 from six intertidal sites in Lake Clark and Katmai National Parks and Preserves, in south-central Alaska. Reference ranges for physiological assays and gene transcription were determined for use in future assessment efforts. Both techniques identified differences among sites, suggesting influences of both large-scale and local environmental factors and underscoring the value of this combined approach to ecosystem health monitoring.

Assessing ecosystem service trade-offs and synergies: The need for a more mechanistic approach

Positive (synergistic) and negative (trade-off) relationships among ecosystem services are influenced by drivers of change, such as policy interventions and environmental variability, and the mechanisms that link these drivers to ecosystem service outcomes. Failure to account for these drivers and mechanisms can result in poorly informed management decisions and reduced ecosystem service provision. Here, we review the literature to determine the extent to which drivers and mechanisms are considered in assessments of ecosystem service relationships. We show that only 19% of assessments explicitly identify the drivers and mechanisms that lead to ecosystem service relationships. While the proportion of assessments considering drivers has increased over time, most of these studies only implicitly consider the drivers of ecosystem service relationships. We recommend more assessments explicitly identify drivers of trade-offs and synergies, which can be achieved through a greater uptake of causal inference and process-based models, to ensure effective management of ecosystem services.

A multidisciplinary analytical framework to delineate spawning areas and quantify larval dispersal in coastal fish

Assessing larval dispersal is essential to understand the structure and dynamics of marine populations. However, knowledge about early-life dispersal is sparse, and so is our understanding of the spawning process, perhaps the most obscure component of biphasic life cycles. Indeed, poorly known species-specific spawning modality and species-specific early-life traits, as well as the high spatio-temporal variability of the oceanic circulation experienced during larval drift, hamper our ability to appraise the realized connectivity of coastal fishes. Here, we propose an analytical framework which combines Lagrangian modelling, network theory, otolith analyses and biogeographical information to pinpoint and characterize larval sources which are then grouped into discrete spawning areas. Such well-delineated larval sources allow improving the quantitative evaluations of both dispersal scales and connectivity patterns. To illustrate its added value, our approach is applied to two case-studies focusing on Diplodus sargus and Diplodus vulgaris in the Adriatic sea. We evidence robust correlations between otolith geochemistry and modelled spawning areas to assess their relative importance for the larval replenishment of the Apulian coast. Our results show that, contrary to D. sargus, D. vulgaris larvae originate from both eastern and western Adriatic shorelines. Our findings also suggest that dispersal distances and dispersal surfaces scale differently with the pelagic larval duration. Furthermore, 30.8% of D. sargus larvae and 23.6% of D. vulgaris larvae of the Apulian populations originate from Marine protected area (MPA), exemplifying larval export from MPAs to surrounding unprotected areas. This flexible multidisciplinary framework, which can be adjusted to any coastal fish and oceanic system, exploits the explanatory power of a dispersal model, fine-tuned and backed-up by observations, to provide more reliable scientific basis for the management and conservation of marine ecosystems.

Coordinating ecosystem service trade-offs to achieve win-win outcomes: A review of the approaches

Ecosystem service (ES) trade-offs have been broadly recognized and studied over the past decade. However, how to coordinate the relationships among ES trade-offs to achieve win-win outcomes remains a considerable challenge for decision makers. Here, we summarize the current approaches applied to minimize ES trade-offs for win-wins and analyze the trade-offs among different ESs and their drivers. Based on a systematic review of the literature from 2005 to 2018, we identified 170 potentially relevant articles, 47 of which were selected for the review, recording 70 actual or potential trade-offs. Analysis of these case studies showed that trade-off pairs between provisioning services and regulating services/biodiversity accounted for 80% of total pairs. Furthermore, more than half of the ES trade-offs were driven by land use/land cover changes. Harvest and resource demand, natural resource management, and policy instruments were also among the main drivers. Four approaches to coordinate ES trade-offs were identified, including ecosystem, landscape-scale, multi-objective optimization, and policy intervention (and other) approaches. Based on the above, we recommend a rigorous understanding of the roles of different stakeholders, spatial scales of management, trade-off dynamics, and integrated implementation of diverse approaches to coordinate ES trade-offs in order to better achieve win-win outcomes.

Managing yield and resilience in a harvested tri-trophic food chain model

In this article, we compare the two ecological services known as yield and resilience, for a tri-trophic food chain model consisting of a prey, an intermediate predator and a top predator. For this comparison process, we use both analytical and numerical techniques. It is shown that a variety of patterns are possible based on the intensity of efforts distributed among different trophic levels. Thus we may suggest that fishing down the food chain, as suggested by Pauly et al. (1998) is not bound to happen. Our analysis also shows that balancing the harvest between prey, intermediate predator and top predator could give more yield and stabilizing the ecosystem, than the selective harvesting of any one species. This balanced harvesting may not be a win-win situation for yield and resilience, but it could be a most favourable strategy to balance them. This research would help to correlate resilience with yield and determines the desirable selection of two policies, resilience maximizing yield or maximum sustainable yield to safeguard ecological communities.

Removal of intertidal grazers by human harvesting leads to alteration of species interactions, community structure and resilience to climate change

Extreme fluctuations in abiotic conditions can induce a biological stress response (e.g. bleaching) detrimental to an organism's health. In some instances, organisms can recover if conditions are alleviated, such as through co-occurrence with other species that confer protection. Biodiverse, multitrophic communities are increasingly recognised as important promoters of species persistence and resilience under environmental change. On intertidal shores, the role of grazers as top-down determinants of algal community structure is well recognised. Similarly, the harvesting of grazers for human consumption is increasingly prevalent with potential to greatly alter the community dynamics. Here, we assess how differences in harvesting pressure of grazers under three management regimes (no-take; managed access; open-access) alters the trophic interactions between grazers, and algal communities. Grazer density and body size frequencies were different among regimes leading to changes in the photosynthetic performance and recovery of crustose coralline algae (CCA) post-bleaching, as well as their presence altering the strength of interactions between species. The exclusion of grazers from patches using cages led to different emergent communities and reduced negative correlations between taxa. The absence of larger grazers (>9 cm) at the managed access site led to macroalgal overgrowth of bleached CCA negatively affecting its recovery, whereas no-take or open-access led to a moderated algal growth and a shift from competitive to facilitative interactions between algal species. Given that CCA play an important role in the population growth and development of other species, the choice of management measure should be carefully considered before implementation, depending on objectives.

Can transplanting enhance mobile marine invertebrates in ecologically engineered rock pools?

The field of eco-engineering has burgeoned in recent years in response to the proliferation of artificial structures. Adding water-retaining features to seawalls has been successful in increasing biodiversity relative to the surrounding structure. Artificial rock pools may not, however, completely mimic natural rock pools. Here, we compared natural colonisation, through dispersal and recruitment, of intertidal mobile species to water-retaining flowerpots on seawalls with that into rock pools. This represents the more usual 'passive' approach to eco-engineering where features are built to enhance biodiversity and are allowed to colonise naturally, as opposed to seeding or transplanting organisms to features. While flowerpots supported some mobile species not found on the seawall, other species common on natural shores did not recruit to flowerpots. Thus, in a second experiment we tested the effectiveness of an 'active' approach through transplanting mobile organisms to flowerpots to expedite the colonisation process. For the species examined, however, most individuals did not stay in the flowerpots for more than 24 h after being transplanted. Further understanding of the processes (e.g. dispersal distances, recruitment) influencing colonisation of eco-engineered habitats is needed to effectively inform management of marine infrastructure, particularly for projects targeted at restoration rather than enhancement.

Removal treatments alter the recruitment dynamics of a global marine invader - Implications for management feasibility

Frameworks designed to prioritise the management of invasive non-native species (INNS) must consider many factors, including their impacts on native biodiversity, ecosystem services, and human health. Management feasibility should also be foremost in any prioritisation process, but is often overlooked, particularly in the marine environment. The Asian kelp, Undaria pinnatifida, is one of the most cosmopolitan marine INNS worldwide and recognised as a priority species for monitoring in the UK and elsewhere. Here, experimental monthly removals of Undaria (from 0.2 m2 patches of floating pontoon) were conducted at two marinas to investigate their influence on recruitment dynamics and the potential implications for management feasibility. Over the 18-month experiment there was no consistent reduction in Undaria recruitment following removals. Cleaning of pontoon surfaces (i.e. removal of all biota) led to significant short-term reductions in recruitment but caused a temporal shift in normal recruitment patterns. Non-selective removal (i.e. all macroalgae) generally promoted recruitment, while selective removal (i.e. Undaria only) had some limited success in reducing overall recruitment. The varied results indicate that the feasibility of limiting Undaria is likely to be very low at sites with established populations and high propagule pressure. However, where there are new incursions, a mixture of cleaning of invaded surfaces prior to normal periods of peak recruitment followed by selective removal may have some potential in limiting Undaria populations within these sites. Multi-factorial experimental manipulations such as this are useful tools for gathering quantitative evidence to support the prioritisation of management measures for marine INNS.

Using Cluster Analysis to Compartmentalize a Large Managed Wetland Based on Physical, Biological, and Climatic Geospatial Attributes

Hierarchical and partitional cluster analyses were used to compartmentalize Water Conservation Area 1, a managed wetland within the Arthur R. Marshall Loxahatchee National Wildlife Refuge in southeast Florida, USA, based on physical, biological, and climatic geospatial attributes. Single, complete, average, and Ward's linkages were tested during the hierarchical cluster analyses, with average linkage providing the best results. In general, the partitional method, partitioning around medoids, found clusters that were more evenly sized and more spatially aggregated than those resulting from the hierarchical analyses. However, hierarchical analysis appeared to be better suited to identify outlier regions that were significantly different from other areas. The clusters identified by geospatial attributes were similar to clusters developed for the interior marsh in a separate study using water quality attributes, suggesting that similar factors have influenced variations in both the set of physical, biological, and climatic attributes selected in this study and water quality parameters. However, geospatial data allowed further subdivision of several interior marsh clusters identified from the water quality data, potentially indicating zones with important differences in function. Identification of these zones can be useful to managers and modelers by informing the distribution of monitoring equipment and personnel as well as delineating regions that may respond similarly to future changes in management or climate.

Effects of sandfish (Holothuria scabra) removal on shallow-water sediments in Fiji

Sea cucumbers play an important role in the recycling and remineralization of organic matter (OM) in reef sands through feeding, excretion, and bioturbation processes. Growing demand from Asian markets has driven the overexploitation of these animals globally. The implications of sea cucumber fisheries for shallow coastal ecosystems and their management remain poorly understood. To address this knowledge gap, the current study manipulated densities of Holothuria scabra within enclosures on a reef flat in Fiji, between August 2015 and February 2016, to study the effects of sea cucumber removal on sedimentary function as a biocatalytic filter system. Three treatments were investigated: (i) high density (350 g m⁻² wet weight; ca. 15 individuals); (ii) natural density (60 g m⁻²; ca. 3 individuals); and (iii) exclusion (0 g m⁻²). Quantity of sediment reworked through ingestion by H. scabra, grain size distribution, O₂ penetration depth, and sedimentary oxygen consumption (SOC) were quantified within each treatment. Findings revealed that the natural population of H. scabra at the study site can rework ca. 10,590 kg dry sediment 1,000 m⁻² year⁻¹; more than twice the turnover rate recorded for H. atra and Stichopus chloronotus. There was a shift towards finer fraction grains in the high treatment. In the exclusion treatment, the O₂ penetration depth decreased by 63% following a 6 °C increase in water temperature over the course of two months, while in the high treatment no such change was observed. SOC rates increased ca. two-fold in the exclusion treatment within the first month, and were consistently higher than in the high treatment. These results suggest that the removal of sea cucumbers can reduce the capacity of sediments to buffer OM pulses, impeding the function and productivity of shallow coastal ecosystems.

Ecological thresholds of hypoxia and sedimentary H2S in coastal soft-bottom habitats: A macroinvertebrate-based assessment

Ecological thresholds of dissolved oxygen (DO) and sedimentary hydrogen sulfide (H₂S) for macrozoobenthos were examined during a 30-month monitoring of two stations in a highly eutrophic canal in inner Tokyo Bay, Japan. Bottom DO and H₂S concentrations fluctuated seasonally, and were significantly correlated with water and sediment temperatures. Red tide-derived phytodetritus was a major source of sediment organic matters in the canal bottom, and the sediment became highly reduced and sulfidic condition in warmer months (sedimentary H₂S; up to 8.5 mM). Dominant opportunistic taxa, including polychaetes and amphipods, were eliminated under low DO and high H₂S conditions (i.e., population thresholds), and devastation of community structure occurred at 2.4-3.3 mg l^-1 DO and 1.8-2.7 mM H₂S (i.e., community thresholds). To maintain ecosystem function in anthropogenically degraded habitats and ensure colonization by macrozoobenthos throughout the year, DO and H₂S levels should be maintained below these thresholds.