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• Revisiting ecosystem resilience to drought using observed water and carbon fluxes. • Ecosystem ET (GPP) decreases 25.3%-50.5% (23.5%-82.5%) during drought. • Ecosystems recover at a rate of 8.5%-24.4% per month and take 4.1-6.7 months. • Ecosystems with less resistance to drought tend to recover more quickly. Drought resistance and drought recovery are important metrics of ecosystems in responding to extreme climate events. However, it remains unclear how drought resistance and drought recovery vary across different ecosystems and whether an internal relationship exists between them. Here, we used observed evapotranspiration and gross primary productivity from 118 flux tower stations worldwide to investigate drought resilience in nine ecosystems. Our results show that drought resistance is higher for evergreen forests but lower for croplands and shrublands. Overall, the ecosystem recovery times ranged from 4.1 to 6.7 months, with a monthly recovery rate ranging from 8.5% to 24.4%. Drought resistance had a negative relationship (R2 = 0.61-0.67, p ≤ 0.01) with the drought recovery rate for the nine selected ecosystems, particularly under mild and moderate drought events. This is beneficial for narrowing the difference in recovery time between ecosystems. Our results provide insights for understanding ecosystem behaviors under climate extremes. [ABSTRACT FROM AUTHOR]

Mangrove forests protect coastal communities from wind and wave energy, including during extreme events such as cyclones and tsunamis. Under extreme conditions, energy absorption often exceeds mangrove tree strength, resulting in broken stems and uprooted trees. Such damage can restructure mangrove community composition and function for decades. Predicting the vulnerability of mangrove forests to damage from external forces is critical for understanding the likelihood of forest structural change during damaging events. Despite the importance of such predictions, we have little mechanistic understanding of mangrove tree strength. We measured mangrove strength across three root types (prop roots, pneumatophores, and buttress roots) using static pulling tests. We applied a non-destructive load to mangrove trees using a winch, and related the force applied to the bending induced in the tree. Mangroves were stronger than terrestrial trees, per unit tree size, and this scaled strength was similar across mangrove species of different root types. Un-scaled mangrove strength increased exponentially with tree size, towards a strength asymptote for the largest trees. Enhanced empirical knowledge of mangrove tree strength is critical to understand the coastal protection services provided by diverse mangrove forests, particularly in a future of global climate change and increased occurrence of extreme storms. [ABSTRACT FROM AUTHOR]

• Annual increased of ecosystem resilience in peripheral cities while that in central cities was decreased. • Economic, population, and urbanization growth were negatively correlated with ecosystem resilience. • Normalized difference vegetation index showed a positive correlation with ecosystem resilience. Ecosystem resilience plays a vital role for security and resilience in the urban system which experiences the combined effects of anthropogenic activities and natural disasters. Nonetheless, there is currently no unified indicator for assessing urban resilience. Therefore, this study aims to examine the changes of ecosystem resilience in the Guangdong-Hong Kong-Macao Great Bay Area (GBA) based on land use, using the framework of resistance, adaption, and elasticity. The study's results revealed that between 2000 and 2020, the increase in ecosystem resilience in peripheral GBA cities outpaced the decrease in central cities, leading to a yearly rise in overall ecosystem resilience. Nighttime light (NL), population density (PD), urbanization rate (UR), and the normalized difference vegetation index (NDVI) were the primary driving factors influencing resistance and elasticity resilience in the GBA, thereby shaping overall ecosystem resilience. Findings from the multi-scale geographical weighted regression (MGWR) analysis demonstrated that ecosystem resilience decreased as NL, PD, and UR increased, while it exhibited an increase in areas with higher NDVI. This study contributes to the improvement of urban resilience in cities by providing targeted strategies, expediting the development of resilient cities, and offering theoretical insights for land management, urban planning, and policy formulation. [ABSTRACT FROM AUTHOR]

In the "new normal" with increasingly obvious uncertain characteristics, China urgently needs to enhance the resilience of blue economy and improve the efficiency of sea-land industrial synergy. In this study, we constructed China's blue product ecosystem and added land products with high technological similarity in it. Then, from the dimensions of economy and network structure, a framework for evaluating the resilience of blue products is designed and the efficiency of China's sea-land industrial synergy is investigated from the perspective of resilience. Finally, based on the "tree" structure characteristic of China's blue product ecosystem found in this research, we designed a cyclically framework consisting of "roots (land technology-related products)-trunk (high resilience hub blue products)-branches (non-hub blue products)" for enhancing blue. The main results are as follows. (1) Land technology-related products are the supporting industry of China's blue economy. (2) Deliberately attacking blue products with strong structural functional resilience will lead to a more rapid "chains broken". (3) The efficiency of sea-land industrial synergy decreased significantly after removing land technology-related products. Our research offers empirical support to assist policy-makers in screening key blue products and industrial chains that warrant cultivation and support to enhance the sustainable development of the blue economy. • Land technology-related products were introduced to build a generalized blue product ecosystem. • Land technology-related industry is an important support for other blue industries. • The efficiency of sea-land industrial synergy was measured from the perspective of ecosystem resilience. • China's blue product ecosystem can be presented by a "tree" structure with "root-trunk-branch". [ABSTRACT FROM AUTHOR]

[Display omitted] • A drought risk assessment framework was constructed using the random forest algorithm. • The drought vulnerability dimension was enriched by considering the impact of ecosystem resilience. • The spatial distribution pattern of drought risk under the influence of ecosystem resilience was assessed. Drought caused by global warming has a profound impact on the stability of terrestrial ecosystems and agricultural production. As one of the key indicators to measure the response of ecosystems to climate change, the spatial difference of ecosystem resilience will also affect the accuracy of regional drought risk assessment. In this study, the 12-month standardized precipitation evapotranspiration index (SPEI-12) was used to identify drought characteristics and combined with meteorological elements to characterize drought hazard. Drought vulnerability was characterized using crop and environmental sensitivity, disaster prevention, and mitigation capacity. Specifically, ecosystem resilience was also considered in assessing vulnerability. And drought exposure was investigated by considering crop sown area and population density. Based on this, a drought risk assessment framework was constructed using the random forest algorithm and applied to the Huang-Huai-Hai (HHH) Plain, China. The results showed that: (1) approximately 66.34 % of the HHH Plain had a drought hazard level above moderate; among them, southern Hebei, northern Anhui, northern Henan, and scattered small areas in Shandong were extreme high hazard areas. (2) The northeast Anhui, central and southern Shandong, and northeast Jiangsu were extreme high drought vulnerability areas, accounting for 10.34% of the total area. (3) The drought risk in the HHH Plain was low in the south and north, and high in the center. Among these, the drought risk in the border regions of Shandong and Anhui, the northeast part of Jiangsu, as well as central Henan were extreme high, accounting for 11.23%. (4) The drought risk assessment framework constructed by considering ecosystem resilience was more suitable for HHH Plain. This study result could provide scientific reference for managing water resources and preventing drought. [ABSTRACT FROM AUTHOR]

Ecological processes may exhibit memory to past disturbances affecting the resilience of ecosystems to future disturbance. Understanding the role of ecological memory in shaping ecosystem responses to disturbance under global change is a critical step toward developing effective adaptive management strategies to maintain ecosystem function and biodiversity. We developed EcoMem, an R package for quantifying ecological memory functions using common environmental time series data (continuous, count, proportional) applying a Bayesian hierarchical framework. The package estimates memory functions for continuous and binary (e.g., disturbance chronology) variables making no a priori assumption on the form of the functions. EcoMem allows users to quantify ecological memory for a wide range of ecosystem processes and responses. The utility of the package to advance understanding of the memory of ecosystems to environmental drivers is demonstrated using a simulated dataset and a case study assessing the memory of boreal tree growth to insect defoliation. • An R package (EcoMem) is introduced to model ecosystem responses to disturbance • EcoMem quantifies the memory of ecological processes to environmental drivers • Memory functions reflect changes in ecosystem resilience over repeated disturbances • Tools are provided to visualize ecological memory and effects on ecosystem function [ABSTRACT FROM AUTHOR]

The most common approach to mitigation of lake eutrophication is reduction of phosphorus emissions, in particular by changing farm management. This reduction can be combined with landscaping retention structures upstream of the lake, the analyses of which the paper is based on. The management of these structures currently focuses on maximising the quantity of phosphorus trapped, regardless of lake dynamics. This paper adapts a dynamical model of lake phosphorus to examine the effects of these phosphorus retention structures. We highlight two effects: first, a structure that traps some of the phosphorus load before it reaches the lake reduces the amount of phosphorus in lake water. Second, some retention structures slow down lake phosphorus dynamics in a way that may perversely slow lake restoration. We propose a cleaning strategy that maximises the chances of restoring a lake to an oligotrophic condition. We demonstrate our model with a real-world case study. • We consider the mitigation of lake eutrophication though different types of retention structures. • We analysed three type of retention effects of a structure on the phosphorus dynamics in the lake. • The efficiency of this structure depends on a trade-off between its delayed effect and sedimentation processes. • Minimising phosphorus input is unexpectedly not always the best solution. [ABSTRACT FROM AUTHOR]

Abstract Mangroves, coastal forests under the influence of tides, are known to be very resilient when they face natural disturbances such as storms or tsunami. While they provide several ecological services, they are threatened by many anthropic pressures. The aim of this study was to assess and to compare the stability of two mangrove fringes defined by contrasted set of natural constraints and exposed to pretreated domestic wastewaters discharges. The in situ experimental system set up in Mayotte Island (Indian Ocean) allowed us to determine both the short-term (2 years) and the long-term (9 years) resistance and the resilience. We focused on vegetation and crabs, an essential component of mangroves fauna. Wastewater discharges induced increases in tree coverage, leaves productivity and pigment content, and a decrease in crab diversity and density. Within 2 years after the release of the disturbance, several parameters reach back control values indicating fast resilience. Our results notably emphasized the high stability of the mangrove fringe dominated by Rhizophora mucronata trees, which was both more resistant and more resilient. This makes this fringe more suitable for application purposes, such as outfall for domestic wastewaters treatment plants. Highlights • The stability (resistance and resilience) of two mangrove zones was studied. • Mangroves were exposed at short and long term to anthropogenic disturbance. • Vegetation growth was enhanced and crab populations were rapidly modified. • Crab and vegetation showed partial resilience within 2 years. • One zone was much more stable than the other one. [ABSTRACT FROM AUTHOR]

Abstract Seagrass meadows ecosystem engineering effects are correlated to their density (which is in turn linked to seasonal cycles) and often cannot be perceived below a given threshold level of engineer density. The density and biomass of seagrass meadows (Z. marina) together with associated macrophytes undergo substantial seasonal changes, with clear declines in winter. The present study aims to test whether the seasonal changes in the density of recovering seagrass meadows affect the benthic food webs of the southern Baltic Sea (Puck Bay). It includes meiofauna, macrofauna and fish of vegetated and unvegetated habitats in summer and winter seasons. Two levels of organization have been tested – species-specific diet preferences using stable isotopes (δ 13C, δ 15N) in Bayesian mixing models (MixSIAR) and the community-scale food web characteristics by means of isotopic niches (SIBER). Between-habitat differences were observed for grazers, as a greater food source diversity in species from vegetated habitats was noted in both seasons. Larger between-habitat differences in winter were documented for suspension/detritus feeders. The community-wide approach showed that the differences between the habitats were greater in winter than in summer (as indicated by the lower overlap of the respective isotope niches). Overall, the presence of seagrass meadows increased ecological stability (in terms of the range of food sources utilized by consumers) in the faunal assemblage, while invertebrates from unvegetated areas shifted their diet to cope with winter conditions. Therefore, as a more complex system, not sensitive to seasonal changes, Z. marina meadows create a stable habitat with high resilience potential. Highlights • Stable isotopes species – specific and community-wide approach are complementary methods to describe ecosystem functioning • The differences in diet preferences of seagrass and bare bottom communities were greater in winter than in summer • Seagrass meadows increased ecological stability in the faunal assemblage • Z. marina meadows create a stable habitat with high resilience potential. [ABSTRACT FROM AUTHOR]

Abstract Herbivory and fire are known to shape plant community structure and function in savanna ecosystems worldwide, yet these drivers are increasingly being altered in their behaviour, or completely excluded. Furthermore, herbaceous responses to rainfall in semi-arid and arid savannas may outweigh the effects of herbivory and fire, especially in nutrient-rich ecosystems. Despite considerable recognition of herbaceous responses to drivers in savanna systems, few studies consider grasses and forbs as distinct herbaceous functional entities. To address this shortcoming, we used long-term herbaceous vegetation data collected from herbivore and fire exclusion treatments in the Kruger National Park (KNP) in South Africa. We investigated response patterns in herbaceous abundances per functional group for three sampling years, which represented different rainfall conditions (i.e., average for 2010, above average for 2001, and below average for 2015. Dynamic shifts in forb versus grass dominance were revealed across treatments. Surprisingly, palatable annual forb communities seemed more resilient to herbivores, or their removal, dominating over palatable annual grass communities. Furthermore, unpalatable perennial forbs were revealed to be more resilient to herbivore presence than their absence. Palatable perennial grass abundances were consistently enhanced by above-average rainfall conditions, whereas equal dominance of palatable grasses and forbs was evident during the drought year. This highlights that palatable perennial functional groups (not grasses alone) provide important ecosystem functions, such as forage stability, and hence functional redundancy to absorb disturbances such as droughts. Moreover, rainfall variability and herbivory are considered the main drivers of palatable perennial functional groups in this nutrient-rich ecosystem. Palatable perennial grass abundances differed significantly from other alleged unfavourable herbaceous functional groups (e.g., unpalatable perennial grasses, annual grasses, and annual and perennial forbs) and, although they presented contrasting patterns for each sampling year, fire and herbivory treatments, palatable perennial grasses remained the dominant functional group in this ecosystem type. Therefore, this study did not support previous findings that conditions such as drought, fire and herbivory favour unfavourable functional groups at the expense of palatable perennial grasses. Observed patterns provide evidence of a dynamic and less predictable coexistence between grasses and forbs. Highlights • Our results provide evidence of dynamic forb-grass coexistence at functional level. • Palatable functional groups provide forage stability and functional redundancy. • Rainfall and herbivory are primary drivers of palatable perennial functional groups. • Palatable annual forb communities are more resilient to herbivory or their removal. • Unpalatable perennial forbs are more adapted to herbivory than to their loss. [ABSTRACT FROM AUTHOR]

Consumer–prey interactions form the foundation of food webs and are affected by the physical environment. Multiple foundational theories in ecology [e.g., the environmental stress model (ESM), the stress–gradient hypothesis (SGH), and ecosystem resilience theory] assume increased physical stress dampens top-down control of prey. In the large majority of empirical studies, however, physical stress either does not affect or amplifies consumer control. Additive and synergistic impacts of physical stress on consumer control appear more common, for example, for herbivory versus predation, and for warm- versus cold-blooded consumers. Predictability in how physical stress affects consumer control, however, remains largely unknown. We expand classical theories in ecology so that their assumption about physical stress–consumer control relationships can be inclusive of what primarily occurs in nature. [ABSTRACT FROM AUTHOR]

Traditional approaches to conservation often focus on plant species composition. In contrast, trait-based approaches highlight the role plant species play in ecosystem function, with a focus on functional diversity and its importance for ecosystem resilience. Here we utilise a plant-trait approach to explore the association between livestock grazing intensity and plant functional diversity in Atlantic oak woodlands, a conservation priority habitat. In two historically un-grazed woodlands (subject to periods of light sheep grazing in winter) paired with two grazed woodlands (intensively grazed by sheep or feral goats), in north-west Wales, UK, field plant-trait data were recorded in three (30 × 4 m) plots per woodland for trees, saplings and understory plants. For trees and saplings, plant-trait data from the field (specific leaf area (SLA) and leaf dry matter content (LDMC)) were combined with plant tolerance indices from the scientific literature (shade, drought and water-logging tolerance) and used to calculate community weighted means (CWM) and functional diversity for plot-level communities. Three plant traits (LDMC, mean foliage height and growth form) and two Ellenberg indices (light and moisture) were combined to calculate CWM and functional diversity for understory plant communities. Tree and sapling communities from grazed woodlands were characterised by response traits associated with grazing avoidance strategies (high LDMC, low SLA), and higher shade – and drought-tolerance scores but lower water-logging-tolerance scores than in un-grazed woodlands. Tree and sapling communities in the un-grazed woodlands had greater seedling establishment, sapling recruitment and functional diversity than in the grazed woodlands. Plant-trait values and functional diversity did not differ with grazing intensity for understory plants. Land managers are increasingly being asked to manage semi-natural habitats for ‘resilience to future events’ such as droughts or floods. Here we demonstrate how a plant-trait approach, including assessment of community-level tolerance indices, allows us to infer potential associations between grazing management, functional diversity and ecosystem resilience. [ABSTRACT FROM AUTHOR]

Rural areas in ecologically fragile regions face obstacles of underdeveloped social economies and poor natural conditions. Existing studies on the optimization of rural settlements in ecologically fragile areas have mainly focused on regional ecological protection and have paid inadequate attention to social-economic dimensions and their interaction with ecological dimensions. We propose an analytical framework for the spatial optimization of rural settlements from a social-ecological perspective. Using Kaitong Town, located in western Jilin Province, China, as a case study, we analysed the development capacity in different villages and evaluated ecosystem resilience. Based on different spatial combinations of rural development capacity and ecosystem resilience, we divided the study area into four zones: relocation and merger; aggregation and promotion; key development; and stabilization and improvement. Rural settlements within the relocation and merger zone were identified as requiring resettlement. Two optimization directions are suggested: one to the key development zone within an adjacent village and the other to the aggregation and promotion zone within the same administrative village. The proposed analytical framework provides a scientific basis for optimizing the layout of rural settlements in ecologically fragile regions and can play an important role in realizing the sustainable development of rural areas. [ABSTRACT FROM AUTHOR]

Kelp forests are one of the most productive ecosystems on earth, providing critical ecosystem services. Despite their global importance, their persistence in the face of human pressure and climate change is uncertain. We present a 38-year quarterly time series of satellite imagery that maps the distribution and persistence of surface canopy-forming kelp (dominated by the bull kelp, Nereocystis leutkeana) forests along eleven degrees of latitude in the western Pacific of the USA. We estimate kelp persistence as the fraction of years occupied by kelp canopy in the time series and evaluate the representation of kelp in marine protected areas (MPAs). While 3.6 % of kelp habitat is fully protected and 10.1 % is partially protected, only 0.7 % of the highly persistent kelp which may be indicative of climate refugia are fully protected. Regionally, the amount of kelp fully protected inside MPAs decreases from Central Northern California (8.0 %) to Oregon (5.9 %), Northern California (1.7 %), and Washington (0 %). Five years after the 2014–2016 marine heatwaves, kelp forests did not recover in California (∼90 % loss for both regions), while Oregon and Washington remained near pre-heatwave values. The low amount of protection in Northern California is concerning and likely exacerbates the vulnerability of kelp and associated species to marine heatwaves. Meeting a target of protecting 10 % of existing kelp habitat will require a 2.5-fold increase in kelp representation in MPAs. Moreover, we propose protecting highly persistent kelp is a cost-effective approach to increase representation and efficacy of MPAs to support climate resilience of kelp forest ecosystems. [ABSTRACT FROM AUTHOR]

When an ecosystem reaches tipping points for selected indicators, resilience to further changes in external drivers can decrease, regime shifts can occur that diminish the capacity of the ecosystem to provide ecosystem services, and the ecosystem is more vulnerable to collapse. Evaluating tipping points for resilience using crisp decision rules can result in decision errors about whether or not resilience has been compromised. The source and nature of those errors are described and a fuzzy decision rule is proposed for evaluating resilience. Decision errors are evaluated for four cases. Cases 1 through 3 (or case 4) derive conditions for evaluating decision errors when there is a single (or multiple) indicator(s). The primary sources of decision errors for the four cases are discrepancies between measured (or established) and true values of the indicators (or tipping points) and using a crisp decision rule to reach conclusions about whether or not resilience has been compromised. A fuzzy decision rule, based on fuzzy TOPSIS, is proposed that evaluates the extent to which an ecosystem is resilient. Although crisp decision rules provide unambiguous conclusions about resilience, those conclusions can be faulty, particularly when measured indicators and established tipping points deviate substantially from their true values. In contrast, the conclusions from the fuzzy decision rule are less susceptible to the decision errors and, hence, faulty decisions. [ABSTRACT FROM AUTHOR]

The resilience of constructed wetland ecosystems to severe disturbance, such as a mass herbivory eat-out or soil disturbance, remains poorly understood. In this study, we use a controlled mesocosm experiment to examine how original planting diversity affects the ability of constructed freshwater wetlands to recover structurally and functionally after a disturbance (i.e., aboveground harvesting and soil coring). We assessed if the planting richness of macrophyte species influences recovery of constructed wetlands one year after a disturbance. Mesocosms were planted in richness groups with various combinations of either 1, 2, 3, or 4 species (RG 1–4) to create a gradient of richness. Structural wetland traits measured include morphological regrowth of macrophytes, soil bulk density, soil moisture, soil %C, and soil %N. Functional wetland traits measured include above ground biomass production, soil potential denitrification, and soil potential microbial respiration. Total mesocosm cover increased along the gradient of plant richness (43.5% in RG 1 to 84.5% in RG 4) in the growing season after the disturbance, although not all planted individuals recovered. This was largely attributed to the dominance of the obligate annual species. The morphology of each species was affected negatively by the disturbance, producing shorter, and fewer stems than in the years prior to the disturbance, suggesting that the communities had not fully recovered one year after the disturbance. Soil characteristics were almost uniform across the planting richness gradient, but for a few exceptions (%C, C:N, and non-growing season soil moisture were higher slightly in RG 2). Denitrification potential (DEA) increased with increasing planting richness and was influenced by the abundance and quality of soil C. Increased open space in unplanted mesocosms and mesocosms with lower species richness increased labile C, leading to higher C mineralization rates. [ABSTRACT FROM AUTHOR]

• Ecosystem heatwave resilience quantified via canopy conductance. • Canopy conductance estimated through inverse calculation of latent heat flux. • Diverse heatwave resilience observed across different ecosystems. • Wetter ecosystems more resistant to short-term heatwaves. • WET and EBF ecosystems more resilient; DBF and ENF ecosystems less so. Heatwaves have increased significantly in recent decades, seriously affecting the biosphere. The vegetation canopy is altered by heatwaves through high temperatures and water deficit, adversely affecting the ecosystem's health. However, how the canopy resilience of different ecosystems responding to heatwaves behaves remains less understood. Canopy conductance (G c) couples the carbon and water cycles and is often used as a proxy for vegetation activity. Here we used eddy-covariance (EC) flux observations and a diagnostic evapotranspiration model to deduce daily canopy conductance inversely. Total 16 flux sites from 2003 to 2014 were used to explore the changes in canopy conductance during heatwaves across multiple ecosystems. Our results showed that the frequency of heatwaves increased significantly in almost all EC sites, and the average heatwave trend was 0.4 d yr−1 (p < 0.05). Wetlands had the best resilience to heatwaves, as indicated by the G c decreasing by 4.6% during heatwaves. For forest ecosystems, the G c of evergreen broadleaf forests decreased by 29.3% during heatwaves, meaning they showed the best resilience to drought. This is followed by the deciduous broadleaf forests and evergreen needleleaf forests, whose G c decreased by 50.7% and 46.3%, respectively. The above results suggest that the resilience of different ecosystems appears diverse during heatwaves. The wetter the ecosystem, the more resistant it is to heatwaves. This study highlights the distinct responses of ecosystems to heatwaves, facilitating our understanding of the influences heatwaves have on terrestrial ecosystems. [ABSTRACT FROM AUTHOR]

Little is known about how biotic interactions will influence the distributions of vegetation types under climate change, but these interactions could determine the effectiveness of conservation actions aimed at encouraging ecosystem migration. Tidal marshes are threatened by sea-level rise worldwide unless losses are offset by landward migration. We conducted extensive vegetation surveys within tidal marshes and tested for evidence of ecosystem migration across three scales in adjacent coastal forest in southern New England. We found widespread shifts in tidal marsh vegetation over decadal scales toward a greater extent of flood-tolerant species (e.g. a 5.4% annual increase in Spartina alterniflora ), but no evidence that coastal forest is changing in a compensatory manner. We found low mortality and high growth rates for trees at the forest edge, suggesting that marsh migration is unlikely in the near term. This apparent mismatch in rates of ecosystem change is likely to result in losses in the extent of high elevation marsh, threatening the persistence of tidal marsh specialists that depend on these areas for reproduction. [ABSTRACT FROM AUTHOR]

Concern is increasing about large-scale dieback that is occurring in many forest ecosystems. However, understanding of the processes of dieback and its potential impacts is limited, partly owing to the lack of long-term monitoring data for forest stands in which dieback has occurred. Here we present monitoring data collected over 50 years along two transects in a temperate forest ecosystem, in which the canopy dominant beech ( Fagus sylvatica L.) has demonstrated significant dieback. Our results show that basal area in the forest has declined by 33%, and juvenile tree densities have also been reduced by approximately 70%. Growing season temperatures have steadily increased and there have been a number of droughts causing climatic water deficits in recent decades, particularly in 1995. We hypothesise that these droughts may have interacted with novel pathogenic fungi to cause mortality of large trees. Curvilinear responses to BA loss were observed in tree community change, ground flora species richness, and percentage cover of grass, providing evidence of thresholds associated with stand dieback. Evidence also suggested that BA failed to recover once it declined. Critical values of basal area for a change in ground flora species richness and grass cover were around 40% decline from initial values. While these changes are dramatic, they cannot be considered a regime shift as the pressures that may have contributed to the ecosystem transition, drought, pathogenic fungi and overgrazing, are on-going. While managers might consider accepting forest dieback as part of an adaptive response of the system to novel environmental conditions, this would likely be associated with significant change in biodiversity and ecosystem service provision. [ABSTRACT FROM AUTHOR]

• WUE in the TP exhibited spatial heterogeneity, reduced under dry and cool conditions. • Grassland in most areas of the TP is resistant to hydroclimatic fluctuations. • Grassland in areas with lower temperature or higher precipitation has greater drought resistance. An increasing trend of hydroclimatic disturbances, such as droughts, which are projected to become more frequent and intense with global warming and climate change. Droughts adversely affect the structure and function of terrestrial ecosystems, damage vegetation growth, and even increase mortality. In this study, we assess the drought resistance (R d) of ecosystems in the Tibetan Plateau. Ecosystem water use efficiency (WUE) was used as an indicator of change in carbon and water cycles, and then ecosystem resistance in terms of change in WUE in drought years was analyzed. Our results suggested that the WUE in the Tibetan Plateau exhibited significant spatial heterogeneity and drastically reduced under dry and cool conditions. The evaluation of ecosystem drought resistance indicated that the grassland in most areas of the Tibetan Plateau is resistant to hydroclimatic fluctuations. In particular, the grassland ecosystem in areas with lower temperatures or higher precipitation exhibited greater drought resistance. Our results facilitate the identification of drought-vulnerable areas in the Tibetan Plateau to inform grassland ecosystem management and climate policy-making and sustain ecosystem stability under future climate conditions. [ABSTRACT FROM AUTHOR]

Research on ecosystem resilience and climate–ecosystem interactions is extremely complex due to the large variety of factors that play a role in ecosystem functioning. This study aimes at determining which factors are involved in ecosystem resilience, which methods are needed to investigate this, and how archaeology can contribute to such research. The influence of the 8.2 ka climate event on the natural environment of Tell Sabi Abyad, Syria, serves as a case study for larger-scale ecosystem resilience studies. This study presents some critical notes to the assumption that the changes which took place in Tell Sabi Abyad at the timing of the 8.2 ka event were a direct result of climate change triggered by the event. Though a number of changes in culture and farming methods date back to the timing of the 8.2 ka event, as yet no evidence has been found for wild flora and fauna shifts which could indicate climate deterioration. Other factors that could have influenced the changes observed in the archaeological record, like anthropogenic influences or cultural development, should not be ruled out as determining factors for the changes that took place at Tell Sabi Abyad at the timing of the 8.2 ka event. [ABSTRACT FROM AUTHOR]

The dynamic nature of biological hotspots, while well recognized, is not well understood. We hypothesize that the persistence of hotspots in the northern California Current System (CCS), despite seasonal and annual changes in the nekton community species composition, is related to associations among species and their functional redundancy. To address this hypothesis, sampling was conducted during June and August of 2000 and 2002 within two hotspots occurring between Newport, Oregon and Crescent City, California in the coastal CCS. Associations were examined to identify potentially complementary and redundant species. The strongest negative associations were between jellyfish and fish species, with strong positive associations evident among several fish species. Dominant species varied seasonally and annually, although evidence indicated replacement of dominant species by other similar species with respect to functional group and preferred habitat. This finding suggests that the persistence of these biological hotspots is related to species redundancy and is an important attribute contributing to stability within this highly variable system. [ABSTRACT FROM AUTHOR]

Ecological studies in tropical rain forests traditionally focus on trees above a threshold diameter at breast height (dbh), since ignoring plant species of the other structural compartments is believed to be an acceptable tradeoff between exhaustiveness and effectiveness. However, the consequences of missing species below a threshold dbh value have been largely neglected so far. We evaluated whether the response of species diversity of ≥10-cm dbh trees was similar to the response of other structural ensembles (namely treelets, saplings, and terricolous herbs) in a lowland tropical rain forest, to three disturbance regimes: natural gap dynamics (control), and selective logging with and without additional thinning. We studied forest vegetation composition and diversity in a 20-yr replicated field experiment comprising nine 1 ha permanent plots established in a semi-deciduous rain forest of the Congo Basin and equally distributed among the three treatments. Once corrected by stem density, species richness was similar between logged (20 years since logging) and untouched old-growth forest stands with respect of trees, but higher with respect of treelets. As disturbance intensity increased, species richness increased within sapling layers but decreased within herb layers, while species spatial turnover (beta diversity) increased in both cases. Regarding the parameters of the partitioned rarefaction curves and relative abundance distribution curves, no correlation was found between trees and any of the other structural compartments. Whilst tree and treelet species composition was similar among treatments, the understories still reflected past disturbance intensity, with a strong response of the sapling and herb layers. These results show that ecological studies based solely on tree layers (dbh ≥ 10 cm) are misleading because their response to disturbance cannot be used as a surrogate for the response of other structural ensembles. Long-lasting effects of anthropogenic disturbance on the sapling bank and the herb layer may durably influence the long-term forest dynamics. Since overstory but not understory plant communities have recovered from human disturbances 20 years after silvicultural operations, African tropical rain forest ecosystems may not be as resilient to selective logging as previously thought. [ABSTRACT FROM AUTHOR]

The EGU gathers geoscientists from Europe and the rest of the world, covering all disciplines of geosciences. Geoscientific interdisciplinarity is needed to tackle future challenges. A major challenge regards the provision of adequate and reliable supplies of affordable energy and resources obtained in environmentally sustainable ways, which are essential for economic prosperity, environmental quality and political stability around the world. One goal of the ERE division is to be a leading discussion forum for these subjects. The contributions in this issue present some of the challenges that were presented in the ERE division at the EGU General Assembly in 2014. [ABSTRACT FROM AUTHOR]

• Increased erosion induced a collapse of the functioning state of the spatially patterned mudflat ecosystem. • Increased river flow enhanced the resilience of the patterned mudflat to erosion by increasing sediment deposition rate. • System with dynamic grazer population was more resilient than the system with a constant grazer number. Estuarine mudflats are profoundly affected by increased coastal erosion and reduced sediment delivery from major rivers. Although managers are having difficulties to control the cause of increased coastal erosion, they can help to manage the resilience of mudflat ecosystems to erosion through river flow regulation. In this study, we associated the resilience of a mudflat ecosystem to erosion with various magnitudes of river flow using a mechanism-based eco-morphodynamic model. Ecosystem resilience was reported in terms of i) what range of erosion rate the system can withstand before function collapse (persistence), ii) at which point function can be recovered (recovery), and iii) the uncertainty of system response to disturbances (response uncertainty). Specifically, the function of intertidal mudflat was characterized by landscape heterogeneity, primary productivity, and sediment stabilization. In a case study of the Yellow River Estuary (YRE) of China, it is found that increased erosion induced a collapse of the functioning state. Once collapsed, the erosion rate at which mudflat could recovered was lower than the erosion rate at which mudflat collapsed. Increased river flow enhanced the resilience of the mudflat ecosystem to erosion by increasing sediment deposition rate, which was an important attribute in the interaction process driving ecosystem resilience. Furthermore, given the same river flow allocation, the system with dynamic grazer population was more resilient than the system with a constant grazer number, highlighting the importance of controlling mudflat aquaculture to optimize the performance of river flow regulation. Our modeling results are dependent on the environment with several assumptions, however, as a preliminary, we believe our work represents a fundamental shift to modeling ecosystem resilience based on the mechanism of bio-physical interactions rather than relying on just quantifying the vital rates of particular species to compare river flow scenarios. [ABSTRACT FROM AUTHOR]

Abstract: The European Geosciences Union brings together geoscientists from all over Europe and the rest of the world, covering all disciplines of the earth sciences. This geoscientific inter- and multidisciplinarity is needed to tackle the challenges of the future. A major challenge for humankind is to provide adequate and reliable supplies of affordable energy and other resources. These should be obtained in environmentally sustainable ways, which is essential for economic prosperity, environmental quality and political stability around the world. This issue gives a general overview of contributions during the General Assembly 2013 in the division for Energy, Resources & the Environment. [Copyright &y& Elsevier]

Abstract: The assessment of total economic value has become a pragmatic and popular approach in nature valuation, yet criticisms have been raised. One major point of critique is that total economic value bases the monetary value of ecosystems purely on the flow of human benefits of services of ecosystems and consequently ignores questions of sustainable use of natural capital per se. This paper explains why total economic value by itself is in principle an inadequate concept to guide sustainable use of ecosystems and gives an overview of essential ecological theory that needs to be taken into account in addition to total economic value to fully include ecosystem sustainability. The paper concludes with a framework for combining ecological theory with economic valuation. The key elements here are theoretical ecological insights about ecosystem resilience and portfolio theory which offers an economic perspective on investment in biodiversity. Portfolio theory puts total economic value in a framework where investment in biodiversity is expanded to cover functional diversity and mobile link species in order to maintain ecosystem resilience and so fosters sustainable use of ecosystems. [Copyright &y& Elsevier]

Abstract: An integrated community resilience index (CRI) quantifies the status, exposure, and recovery of the physical, economic, and socio-cultural capital for a specific target community. However, most CRIs do not account for the recovery of ecosystem functioning after extreme events, even though many aspects of a community depend on the services provided by the natural environment. The primary goal of this study was to monitor the recovery of ecosystem functionality (ecological capital) using remote sensing-derived gross primary production (GPP) as an indicator of ‘ecosystem-wellness’ and assess the effect of resilience of ecological capital on the recovery of a community via an integrated CRI. We developed a measure of ecosystem resilience using remotely sensed GPP data and applied the modeling prototype ResilUS in a pilot study for a four-parish coastal community in southwestern Louisiana, USA that was impacted by Hurricane Rita in 2005. The results illustrate that after such an extreme event, the recovery of ecological capital varies according to land use type and may take many months to return to full functionality. This variable recovery can potentially impact the recovery of certain businesses that rely heavily on ecosystem services such as agriculture, forestry, fisheries, and tourism. [Copyright &y& Elsevier]

Abstract: Surveys of stranded marine debris around Motupore Island, a small island in Bootless Bay, Papua New Guinea, revealed exceptionally high loads (up to 78.3itemsm−2), with major concentrations in mangrove-dominated, depositional areas. The worst affected, 50-m stretch of shore was estimated to contain >37.000 items with a combined weight of 889kg. Consistent with studies elsewhere, plastics comprised by far the majority of debris across all sites (89.7%). The lack of centralised waste collection and limited village-based resources, coupled with an increasing population, suggests that this issue is a long way from solution. High debris loads thwart attempts to rehabilitate depleted mangrove forests through smothering of seedlings, perpetuating run-off and water quality issues in the bay. Addressing marine debris is thus of fundamental importance for the sustainability of Bootless Bay and its resources, and a critical step in promoting ecosystem resilience. [Copyright &y& Elsevier]

Abstract: Recent research has produced broad application of the health concept to regional ecosystems, including the Great Lakes. The attention is warranted, as new and recurring stresses on the health of the Great Lakes undermine our understanding and hinder our ability to manage and restore critical ecological functions. There is widespread agreement that the Great Lakes are presently exhibiting symptoms of extreme stress and potentially irreversible and catastrophic damage. Historical command and control management has resulted simultaneously in environmental benefits to people and a loss of resilience in Great Lakes ecosystems. Surprising system responses often prompt further control, and the continued decline in resilience has been called the pathology of natural resource management. The pathology is also suggested to affect human systems of organization such as management authorities. We use published criteria of institutional pathologies and illustrate their occurrence in the Great Lakes with evidence of non-existent program evaluation, program incompatibility, lack of coordination among programs, authorities that establish and then abandon public participatory initiatives, and inappropriate choice of policy mechanisms or inadequate level of support for an appropriate mechanism (either of which creates disincentives for stakeholders). Learning is an element of resilience, as managed systems are inherently dynamic and our understanding is therefore always incomplete. Policy mechanisms that mimic learning techniques to improve understanding are therefore central to avoiding pathologies in management. But learning (individually or institutionally) can be threatening and very difficult, and its proper conduct necessarily involves a continuous process of feedback, interpretation, and reformulation. Double-loop learning processes that institutionalize learning in policy are recommended, as these will be required to overcome pathologies in management and maintain resilience of the Great Lakes system. [Copyright &y& Elsevier]

Abstract: Ecosystem resilience as a key target of the sustainable development of forest resource. Diagnosis of ecosytem resilience is an important premise for maintaining the sustainable development of the ecosytem and socio-economic system. But researches on ecosytem resilience still lingered on its definition and case studies, there have been only few researches on its quantitative measurement so far. It is a hopeful method to quantitatively measure forest ecosytem resilience with its influencing factors, but there has been fewer researches. this paper has first reviewed the development of the definition of ecosystem resilience and discussed its current measurement methods. Next, the recorded influencing factors of ecosystem resilience were illustrated and finally the further research directions were discussed. [Copyright &y& Elsevier]

Resilience as a descriptive concept gives insight into the dynamic properties of an ecological-economic system. Sustainability as a normative concept captures basic ideas of intergenerational justice when human well-being depends on natural capital and services. Thus, resilience and sustainability are independent concepts. In this paper, we discuss the relationship between resilience and sustainability of ecological-economic systems. We use a simple dynamic model where two natural capital stocks provide ecosystem services that are complements for human well-being, to illustrate different possible cases of the relationship between resilience and sustainability, and to identify the conditions under which each of those will hold: a) resilience of the system is necessary, but not sufficient, for sustainability; b) resilience of the system is sufficient, but not necessary, for sustainability; c) resilience of the system is neither necessary nor sufficient for sustainability; and d) resilience is both necessary and sufficient for sustainability. We conclude that more criteria than just resilience have to be taken into account when designing policies for the sustainable development of ecological-economic systems, and, vice versa, the property of resilience should not be confused with the positive normative connotations of sustainability. [Copyright &y& Elsevier]

Abstract: Lake Chilwa is shared by Malawi and Mozambique, it supports an important fishery and its watershed is undergoing rapid population growth and increasing utilization for agricultural production. It is a shallow, closed basin lake with extensive surrounding wetlands; and it has suffered several desiccation events in the last century. To better understand the current condition of the lake, we monitored a suite of physical, chemical and biological parameters at approximately monthly intervals over an annual cycle in 2004–2005. The limnology of the lake was extremely sensitive to seasonal changes in the lake''s seasonal hydrological cycle. The physico-chemical parameters, temperature, electrical conductivity, and total suspended solids exhibited clear seasonal patterns driven by the highly seasonal rainfall and resultant lake levels. In response, phytoplankton and zooplankton abundance, as well as biologically dependent oxygen concentrations and pH, exhibited several maxima levels over the year. The peaks of phytoplankton and zooplankton were out of phase suggesting a lag in the zooplankton grazing in response to pulses in primary productivity. Chlorophyll concentrations can exceed 1mg/L in surface waters indicative of hypereutrophic conditions, but they fell dramatically during zooplankton peaks. This hydrologically driven, shallow and mesohaline lake is a productive and critical resource to the region. Its management poses challenges arising from the dependence of its limnology and fishery on the lakes hydrology, catchment land use and climate variability. [Copyright &y& Elsevier]

Abstract: A fertilisation experiment was started in the French Alps on an acid grassland at 2000m in 1989 where lime as calcium carbonate (“liming”) and Thomas Slag enriched by potassium chloride (“fertilisation”) were added in a random block design until 1992. Since then, no further amendments were applied. Fifteen years after the last application, we revisited the experiment and observed that soil pH was still significantly higher on limed plots, while nitrogen (N) concentrations were lower. On fertilised plots, soil carbon (C) and N concentrations were lower compared to unfertilised plots. However, litter quality (C and N concentrations, near infrared spectroscopy [NIRS] data) was similar for both treatments. Vegetation composition, but not species richness, nor Shannon–Wiener or evenness differed between limed and unlimed plots, and fertilised and unfertilised plots. Liming explained about 18% and fertilisation about 6% of the variability of the vegetation composition. These changes in the vegetation composition are probably due to lower abundances of former dominant grass species and to an increase in generalist grasses. However, these changes did not influence the total above-ground productivity, which was similar for all treatments. Tissue N and C concentrations and NIRS data indicated a changed chemical composition of the biomass which persisted during time. We conclude that the 3 years of fertilisation and liming did substantially influence the vegetation composition at our site and lead to an increase in the agricultural value of the grassland. These changes are long-lasting as they changed key features of the functioning in the soil of grasslands ecosystems. From an ecological point of view, specialised vegetation was replaced by generalist species leading to a trivialisation of the vegetation. [Copyright &y& Elsevier]

How best to optimize the biodiversity gain from agri-environment schemes (AES) has recently been identified as a key policy-relevant question. Here, the effects of two features of lowland agricultural landscapes on the abundance and diversity of larger moths are contrasted. Although both features bring about positive effects, hedgerow trees have a larger impact than 6m wide grassy field margins. Whilst AES payments are given to create and maintain grass margins, no financial reward is currently offered for the retention of hedgerow trees. Furthermore, it was only in areas where the amount of land under AES was experimentally increased, by targeting farmers, that the presence of hedgerow trees resulted in a substantially higher abundance (+60%) and diversity (+38%) of moths. Thus, by using larger moths as bio-indicators of landscape-scale quality, it is demonstrated that improvements to the cost-effectiveness of AES could be achieved, firstly, by providing more appropriate financial rewards to farmers for different landscape features, and secondly, through landscape-scale targeting of farmers to encourage participation in AES. [Copyright &y& Elsevier]

The concept of resilience can be helpful in describing the relationship between vegetation and climate, especially when considering the likelihood of more extreme climate events due to global warming. However, the quantification and characterization of resilience is a challenge, due to the inherent complexity of the concept, as well as difficulty in comparing different ecosystems across the globe. In order to explore ecosystem resilience to drought, we estimated the resilience and related metrics from a series of land surface model (LSM) simulations with altered climate forcing data, focusing on the responses to changing precipitation. These simulations were performed in the semi-arid region of Caatinga biome, northeastern Brazil. Results showed that the quantification of resilience can be represented as a function between precipitation variation and gross primary productivity (GPP) variation. We compared the resilience components estimated for different vegetation types, which showed differences in the response of vegetation to precipitation variability. The study shows the potential of using LSMs to improve our understanding of the vegetation response to climate change, allowing us to explore possible scenarios that are usually not available in field experiments. • Use of Land Surface Models to explore ecological resilience metrics. • Different vegetation types presented different resilience to drought. • The assumed trade off between Recovery and Impact was not observed in all cases. [ABSTRACT FROM AUTHOR]

Mediterranean coastal ecosystems provide various valuable ecosystem goods and services; however, they are vulnerable to ecological degradation due to a dramatic increase in resource use and environmental stress. Disentangling the effects of multiple human interventions on coastal ecosystems requires whole description of food web interactions using quantitative tools. A mass balance Ecopath model has been developed here for Saronikos Gulf, a naturally oligotrophic Mediterranean coastal ecosystem with a long history of human interventions. Our main focus was to describe the structure and functioning of the ecosystem, investigate the trophic interplay among the various compartments of the food web under the impact of mixed multi-gear fisheries, and to quantify resilience related emergent ecosystem properties. To this end, we reviewed a large amount of local and regional biological information which was integrated in 40 functional groups covering all trophic levels, while fishing activities were described with 7 fleets. The model shared characteristics of both productive (e.g., high amount of flows) and oligotrophic systems (e.g., low biomass accumulation) and presented typical features of Mediterranean ecosystem functioning, such as the importance of detritus as an energy source, strong benthic-pelagic coupling and the dominance of the pelagic compartment in terms of total production and consumption. Trophic forcing in the ecosystem of Saronikos Gulf was complex with both top-down and bottom-up drivers being important. Zooplankton was the central nexus between basal resources and higher trophic levels, while top predators such as hake, squids and anglerfish were identified as keystone species presenting a significant overall effect on the food web via direct and indirect trophic interactions. Ecological indicators depicted a moderately complex food-web of a large and immature ecosystem with its strengths in reserve being affected by environmental degradation. Additionally, exploitation indices classified fishing activities in Saronikos Gulf as unsustainable, affecting several target groups, including high trophic level species. However, the morphological and bathymetric complexity of Saronikos Gulf seems to function as a natural ecological reserve for the ecosystem by providing nursery grounds to various species (e.g., hake, small pelagic fishes) and supporting important fish stocks for local fisheries. • A trophic model of Saronikos Gulf was constructed considering 40 functional groups. • Saronikos Gulf presented typical Mediterranean ecosystem functioning traits. • Anthropogenic stressors are impacting ecosystem function. • Complex trophic forcing with both top-down and bottom-up control. • Spatial heterogeneity functions as a natural ecological reserve for the ecosystem. [ABSTRACT FROM AUTHOR]

Abstract: Healthy forests provide many of the essential ecosystem services upon which all life depends. Genetic diversity is an essential component of long-term forest health because it provides a basis for adaptation and resilience to environmental stress and change. In addition to natural processes, numerous anthropogenic factors deplete forest genetic resources. Genetic losses could be particularly consequential now because robust resilience is needed to respond to a growing number, variety, and frequency of stress exposures. Silvicultural management that selectively removes trees (and their genes) from forests may be another force reshaping forest gene pools. Although data concerning the influence of silvicultural management on genetic resources in temperate forests is somewhat mixed, through the genetic assessment of long-term silvicultural treatments within an eastern hemlock (Tsuga canadensis) forest, and computer-based simulated harvests of a genetically mapped eastern white pine (Pinus strobus) stand, we found that the selective removal of trees can alter gene frequencies. Due to an association with phenotypic characteristics used to guide harvests, the frequencies of rare alleles appeared particularly vulnerable to manipulation. Depending on the selection criteria used, rare allele frequencies either remained steady, decreased, or increased relative to study controls. Although harvest-associated genetic losses are possible, our data suggests that management can also sustain or enhance genetic richness. Similar to studies within temperate ecosystems, recent research in tropical forests underscores the potential influence of harvesting on the genetics of tree populations. In addition to efforts to reduce controllable sources of ecosystem stress (e.g., high pollutant exposures), management options should be evaluated that may bolster forest ecosystem resilience by preserving levels of genetic diversity within forests. [Copyright &y& Elsevier]

Abstract: Simple models have significant contribution to the development of ecological theory. However, these minimalistic modeling approaches usually focus on a small subset of the causes of a phenomenon and neglect important aspects of system dynamics. In this study, we use a complex aquatic biogeochemical model to examine competition patterns and structural shifts in the phytoplankton community under nutrient enrichment conditions. Our model simulates multiple elemental cycles (org. C, N, P, Si, O), multiple functional phytoplankton (diatoms, green algae and cyanobacteria) and zooplankton (copepods and cladocerans) groups. It also takes into account recent advances in stoichiometric nutrient recycling theory, and the zooplankton grazing term is reformulated to include algal food quality effects on zooplankton assimilation efficiency. The model provided a realistic platform to examine the functional properties (e.g., kinetics, growth strategies, intracellular storage capacity) and the abiotic conditions (temperature, nutrient loading) under which the different phytoplankton groups can dominate or can be competitively excluded in oligo, meso and eutrophic environments. Based on the results of our analysis, the intergroup variability in the minimum cell quota and maximum transport rate at the cell surface for phosphorus along with the group-specific metabolic losses can shape the structure of plankton communities. We also use classification tree analysis to elucidate aspects (e.g., relative differences in the functional group properties, critical values of the abiotic conditions, levels of the other plankton community residents) of the complex interplay among physical, chemical and biological factors that drive epilimnetic plankton dynamics. Finally, our study highlights the importance of improving the mathematical representation of phytoplankton adaptive strategies for resources procurement (e.g., regulation of transport kinetics, effects of transport kinetics on the kinetics of assimilation, relationship between assimilation and growth) to effectively link variability at the organismal level with ecosystem-scale patterns. [Copyright &y& Elsevier]

Abstract: During four decades, the Ria de Aveiro was subjected to the loading of mercury from a chlor-alkali industry, resulting in the deposition of several tons of mercury in the sediments. The present study evaluates the impact of this disturbance and the recovery processes, temporally and spatially, by means of examining the richness of the species of salt marsh plants and mercury concentrations in sediments over the last fifty years. The temporal assessment showed that the mercury loading induced a shift in the species composition of the salt marsh from a non-disturbed salt marsh with higher species richness to an alternative state dominated by Phragmites australis. The horizontal assessment, through a mercury gradient, presents the same trend, indicating that P. australis is the species most tolerant to higher mercury concentrations, comparative to Halimione portulacoides, Arthrocnemum fruticosum, Triglochin maritima, Juncus maritimus and Scirpus maritimus. After the reduction of mercury discharges in 1994, the salt marsh shows a slowly return path recovery response. The hysteresis in the response results in the temporal gap between the reduction in mercury concentrations in the sediment and the salt marsh species richness response, comparatively to the existing diversity in the local reference marsh. [Copyright &y& Elsevier]

Abstract: In the life and natural sciences, the concept of thresholds or points or zones of change from one state to another has been investigated since the late 18th century. Over the past three decades, ecologists and economists around the world have been examining the existence and use of ‘ecological thresholds’ in natural and modified systems, primarily as a conceptual basis for the development of tools to conserve and sustainably manage natural resources. In Australia, there has been a recent renewed interest in the definition and application of ecological thresholds in the conservation of threatened fauna and flora, modelling the impact of habitat loss, modification and fragmentation on terrestrial biota, management of pest plant and animal species, and development of natural resource management policies and plans. This paper reviews the threshold concept from an ecological perspective. It considers the definition, types and behaviour of this phenomenon. The theoretical and empirical evidence for their purported existence is reviewed and their potential utility in biodiversity conservation and natural resource management is discussed, along with key issues relating to their use. [Copyright &y& Elsevier]

The ecological evaluation index (EEI) was designed to estimate the ecological status of transitional and coastal waters. Marine benthic macrophytes (seaweeds, seagrasses) were used as bioindicators of ecosystem shifts due to anthropogenic stress, from the pristine state with late-successional species (high ecological status class (ESC)) to the degraded state with opportunistic species (bad ESC). The relation of EEI to function and to resilience of the marine ecosystem, and its possibility for comparing and ranking at local, national and international levels are some of its main management implications. [Copyright &y& Elsevier]

Climate change is expected to increase the frequency and severity of droughts in many regions of the world. Soil health is likely to be negatively impacted by these extreme events. It is therefore important to understand the impact of drought on soil functioning and the delivery of soil-related ecosystem services. This study aimed to assess the resilience and change in physiological status of the microbial community under extreme moisture stress conditions using novel metabolic profiling approaches, namely complex lipids and untargeted primary metabolites. In addition, we used phospholipid fatty acid (PLFA) profiling to identify changes in microbial community structure. Soil samples were collected during a natural, extreme drought event and post-drought from replicated grassland split plots, planted with either deep-rooting Festulolium (cv. AberNiche) or Lolium perenne L. (cv. AberEcho), receiving nitrogen (N) fertiliser loading rates at either 0 or 300 kg N ha−1 yr−1. These plots were split at the start of the drought period, and half of each subplot was irrigated with water throughout the drought period at a rate of 50 mm week−1 to alleviate moisture stress. PLFA analysis revealed a distinct shift in microbial community between drought and post-drought conditions, primarily driven by N loading and water deficit. Complex lipid analysis identified 239 compounds and untargeted analysis of primary metabolites identified 155 compounds. Both soil complex lipids and primary metabolites showed significant changes under drought conditions. Additionally, the irrigated 'reference' plots had a significantly higher cumulative greenhouse gas (CO 2 and N 2 O) flux over the period of sampling. Recovery of the microbial lipidome and metabolome to reference plot levels post-drought was rapid (within days). Considerable changes in soil primary metabolomic and lipidomic concentrations shown in this study demonstrate that while soil metabolism was strongly affected by moisture stress, the system (plant and soil) was highly resilient to an intense drought. • Novel exploration of soil complex lipids and metabolites during natural drought. • Identification of bioindicator compounds associated with drought and N fertilisation. • Drought rather than N loading rate had the greatest effect on the soil metabolome. • Use of a drought-resistant grass variety had no major effect on the metabolome. • The system (plant and soil) was shown to be highly resilient to drought. [ABSTRACT FROM AUTHOR]