Increases Ecosystem Stability Research Articles

Inhibition mechanism of Microcystis aeruginosa in coculture of Lemna and Azolla: Insights from non-targeted Metabonomics.

Microcystis aeruginosa, a harmful alga in cyanobacterial blooms, damages aquatic ecosystems. Species diversity may control the blooms by increasing ecosystem stability and resource utilization. The growth and photosynthetic systems of M. aeruginosa were investigated using the water from monocultures of Lemna aequinoctialis and Azolla imbricata group, as well as their mixtures. The highest rate of inhibition (84%) of M. aeruginosa was observed in the water excretions from the mixture of the two species across the three experimental groups. Greater disruption of cell membranes and a more significant decrease in the maximum electron transfer rate and photochemical quantum yield of M. aeruginosa were observed under mixed conditions compared to the monoculture, indicating the increased disruption of their photosynthetic systems in the mixed group. Liquid chromatography-mass spectrometry identified 479 and 431 differential metabolites in the mixed group compared to monocultures of L. aequinoctialis group and A. imbricata, respectively. Dihydrocapsaicin and 13-hydroxy-9-methoxy-10-oxo-11-octadecenoic acid, previously known to participate in oxidative stress and induce the secretion of benzoic acid to disrupt the cell membrane, were found to be abundant in the mixed group compared to the monoculture groups of L. aequinoctialis and A. imbricata. Our results showed that a mixture of L. aequinoctialis and A. imbricata is a potential novel antialgal agent to inhibit harmful algae.

Long-term marine protection enhances kelp forest ecosystem stability.

Trophic downgrading destabilizes ecosystems and can drive large-scale shifts in ecosystem state. While restoring predatory interactions in marine reserves can reverse anthropogenic-driven shifts, empirical evidence of increased ecosystem stability and persistence in the presence of predators is scant. We compared temporal variation in rocky reef ecosystem state in New Zealand's oldest marine reserve to nearby fished reefs to examine whether protection of predators led to more persistent and stable reef ecosystem states in the marine reserve. Contrasting ecosystem states were found between reserve and fished sites, and this persisted over the 22-year study period. Fished sites were predominantly urchin barrens but occasionally fluctuated to short-lived turfs and mixed algal forests, while reserve sites displayed unidirectional successional trajectories toward stable kelp forests (Ecklonia radiata) taking up to three decades following protection. This provides empirical evidence that long-term protection of predators facilitates kelp forest recovery, resists shifts to denuded alternate states, and enhances kelp forest stability.

Forest microbiome and global change.

Forests influence climate and mitigate global change through the storage of carbon in soils. In turn, these complex ecosystems face important challenges, including increases in carbon dioxide, warming, drought and fire, pest outbreaks and nitrogen deposition. The response of forests to these changes is largely mediated by microorganisms, especially fungi and bacteria. The effects of global change differ among boreal, temperate and tropical forests. The future of forests depends mostly on the performance and balance of fungal symbiotic guilds, saprotrophic fungi and bacteria, and fungal plant pathogens. Drought severely weakens forest resilience, as it triggers adverse processes such as pathogen outbreaks and fires that impact the microbial and forest performance for carbon storage and nutrient turnover. Nitrogen deposition also substantially affects forest microbial processes, with a pronounced effect in the temperate zone. Considering plant-microorganism interactions would help predict the future of forests and identify management strategies to increase ecosystem stability and alleviate climate change effects. In this Review, we describe the impact of global change on the forest ecosystem and its microbiome across different climatic zones. We propose potential approaches to control the adverse effects of global change on forest stability, and present future research directions to understand the changes ahead.

Global variation in unique and redundant mammal functional diversity across the daily cycle

AbstractAimOrganisms primarily influence ecosystems through their functional traits when they are physically active. Following the nocturnal bottleneck, the expansion of mammals into the daytime expanded mammalian functional diversity (FD), however there is also notable overlap in trait space across diel niches leading to redundant FD. We explore how the unique and redundant contribution of each diel niche varies spatially and in relation to natural variation in light and temperature.LocationGlobal.TaxonExtant mammals.MethodsBased on five major functional traits (body mass, litter size, diet breadth, foraging strata, habitat breadth) for 5033 extant terrestrial mammals, we determine biogeographical variation in nocturnal, crepuscular, cathemeral and diurnal FD. We calculate the proportion of mammalian FD that is unique to each diel niche, and the proportion that is redundant across the daily cycle.ResultsThe diversification of mammals into the daytime resulted in the creation of new FD (28.5% of FD is not nocturnal; Lower Quartile 17.3%; Upper Quartile 38.2%). Most of this expansion occurred at higher latitudes where uniquely cathemeral FD dominates (>55°N, 41.1% of mammalian FD; Lower Quartile 33.3%, Upper Quartile 53.6%), associated with fewer hours of biologically useful moonlight and daylight. Where there are more hours of biologically useful daylight, unique diurnal FD is common. However, more than half of non‐nocturnal FD is redundant, increasing ecosystem stability as different species carry out similar functions at different times of day, and suggesting that many mammals have not diversified far from their nocturnal ancestors.Main conclusionsOver much of the land surface more than a half of FD only occurs at night, underscoring the importance of nocturnal mammals for ecosystems. Understanding diel variation in FD not only informs on community structure and ecosystem function but also on ecosystem functional persistence in the Anthropocene, with pressures at night being particularly concerning.

Taxonomic diversity and eco-exergy changes in fishery resources associated with artificial reefs over 14 years in Daya Bay, China

Marine habitat degradation resulting from human activities and environmental pollution has led to serious deterioration of marine fishery resources. To address this issue, countries worldwide are exploring sustainable fishery approaches. Installation of artificial reefs (AR) is rapidly increasing. AR have been widely constructed globally to conserve fishery resources and improve marine habitats. As an important biological group of marine fishery resources, nekton are widely evaluated to determine the effects of ecological restoration and resource conservation. In the current study, we compared the dynamic properties of taxonomic diversity and the eco-exergy of nekton community from 2 to 14 years after AR construction in Dalajia, China. The results indicated that the species number and density of nekton significantly increased after AR construction. Siganus oramin became an absolute dominant fish species in the reef area and its surroundings. The species diversity and evenness of the nekton community decreased, whereas species richness increased. The abundance, biomass, and eco-exergy of the nekton community increased over time because of the dominance of fishes. Our results highlight that AR can increase and conserve fishery resources, improve the structure of the nekton community, and increase ecosystem stability. But, at the same time, the dominance of S. oramin can interfere in the reef community. The explosive growth was quantitatively and qualitatively higher than that of other species, the diversity and evenness indices showed a decreasing trend, although the number of nekton species was significantly higher than that in the background survey and CA habitat during the same period.

High seed diversity and availability increase rodent community stability under human disturbance and climate variation.

The relationship between diversity and stability is a focus in community ecology, but the relevant hypotheses have not been rigorously tested at trophic and network levels due to a lack of long-term data of species interactions. Here, by using seed tagging and infrared camera tracking methods, we qualified the seed-rodent interactions, and analyzed the associations of rodent community stability with species diversity, species abundance, and seed-rodent network complexity of 15 patches in a subtropical forest from 2013 to 2021.A total of 47,400 seeds were released, 1,467 rodents were marked, and 110 seed-rodent networks were reconstructed to estimate species richness, species abundance, and seed-rodent network metrics. We found, from younger to older stands, species richness and abundance (biomass) of seeds increased, while those of rodents decreased, leading to a seed-rodent network with higher nestedness, linkage density, and generality in older stands, but higher connectance in younger stands. With the increase of temperature and precipitation, seed abundance (biomass), rodent abundance, and the growth rate of rodent abundance increased significantly. We found rodent community stability (i.e., the inverse of rodent abundance variability) was significantly and positively associated with seed diversity, seed availability, linkage density and generality of seed-rodent networks, providing evidence of supporting the Bottom-Up Diversity-Stability Hypotheses and the Abundant Food Diversity-Stability Hypothesis. Our findings highlight the significant role of resource diversity and availability in promoting consumers' community stability at trophic and network levels, and the necessity of protecting biodiversity for increasing ecosystem stability under human disturbance and climate variation.

Environmental filtering of macroinvertebrate traits influences ecosystem functioning in a large river floodplain

AbstractThe biodiversity–ecosystem function hypothesis postulates that higher biodiversity is correlated with faster ecosystem process rates and increased ecosystem stability in fluctuating environments. Exhibiting high spatiotemporal habitat diversity, floodplains are highly productive ecosystems, supporting communities that are naturally resilient and highly diverse.We examined linkages among floodplain wetland habitats, invertebrate communities and their associated traits, and ecosystem function across 60 sites within the floodplain wetlands of the lower Wolastoq | Saint John River, New Brunswick, using structural equation modelling and Threshold Indicator Taxa ANalysis.We identified key environmental filters structuring invertebrate communities, by linking increased niche differentiation through shoreline change, flood pulse dynamics, and macrophyte bed complexity with increased taxa and functional diversity.Examination of traits linked to ecosystem functions revealed that more resilient wetlands with balance between primary productivity and decomposition as carbon sources were associated with greater functional evenness and richness, while habitat patches with elevated decomposition rates had lower functional richness, reflecting a simplified, more disturbed habitat.While our more complex overarching SEM model was ultimately compromised by an overspecified number of pathways, our results nevertheless are indicative of a divergence between wetland and riverine ecosystems in their relationships linking biodiversity and ecosystem function, illustrating how to define ecosystem health in wetland habitats, and demonstrating how critical functions support healthy wetland habitats by providing increased resilience to disturbance.Read the freePlain Language Summaryfor this article on the Journal blog.

Temporal Dynamics in Energy Fluxes and Trophic Structure of a Portunus trituberculatus Polyculture Ecosystem During Different Culture Periods

Swimming crab (Portunus trituberculatus) are an important aquaculture species in eastern coastal areas of China. To improve the understanding of P. trituberculatus culture ecosystem functioning, the dynamics of energy flow and trophic structure of a P. trituberculatus polyculture system (co-culture with white shrimp Litopenaeus vannamei and short-necked clam Ruditapes philippinarum) were investigated in this study. Three Ecopath models representing the early, middle, and late culture periods of a P. trituberculatus polyculture ecosystem, respectively, were constructed to compare ecosystem traits at different culture periods. The results demonstrated that detritus was the main energy source in this polyculture ecosystem, and most of the total system throughput occurred at trophic levels I and II. Artificial food input and consumption by the culture organisms increased from early to middle and late periods, which produced marked impacts on biomass structure and primary production. R. philippinarum was considered to have a dominant influence on phytoplankton community dynamics which changed from nano- to pico-phytoplankton predominance, from the middle to the late period. Considering the low utilization efficiency of pico-phytoplankton production, large amounts of detritus accumulated in the sediment in the late period, which may constitute a potential risk for the ecosystem. Ecological network analyses indicated that the total energy flow and level of system organization increased from the early to the middle and late periods, whereas food web complexity and system resilience decreased from early to middle and late periods, which may indicate a trend of decreasing ecosystem stability. The system may be further optimized by increased stocking density of R. philippinarum and by introducing macro-algae at a suitable biomass to increase ecosystem stability, energy utilization efficiency, and aquaculture production.

Consistently positive effect of species diversity on ecosystem, but not population, temporal stability.

Despite much recent progress, our understanding of diversity-stability relationships across different study systems remains incomplete. In particular, recent theory clarified that within-species population stability and among-species asynchronous population dynamics combine to determine ecosystem temporal stability, but their relative importance in modulating diversity-ecosystem temporal stability relationships in different ecosystems remains unclear. We addressed this issue with a meta-analysis of empirical studies of ecosystem and population temporal stability in relation to species diversity across a range of taxa and ecosystems. We show that ecosystem temporal stability tended to increase with species diversity, regardless of study systems. Increasing diversity promoted asynchrony, which, in turn, contributed to increased ecosystem stability. The positive diversity-ecosystem stability relationship persisted even after accounting for the influences of environmental covariates (e.g., precipitation and nutrient input). By contrast, species diversity tended to reduce population temporal stability in terrestrial systems but increase population temporal stability in aquatic systems, suggesting that asynchronous dynamics among species are essential for stabilizing diverse terrestrial ecosystems. We conclude that there is compelling empirical evidence for a general positive relationship between species diversity and ecosystem-level temporal stability, but the contrasting diversity-population temporal stability relationships between terrestrial and aquatic systems call for more investigations into their underlying mechanisms.

Prior exposure to stress allows the maintenance of an ecosystem cycle following severe acidification

Ecosystem processes vary temporally due to environmental fluctuations, such as when variation in solar energy causes diurnal cycles in primary production. This normal variation in ecosystem functioning may be disrupted and even lost if taxa contributing to functioning go extinct due to environmental stress. However, when communities are exposed to the stress at sub‐lethal levels over several generations, they may be able to develop community‐level stress tolerance via ecological (e.g. species sorting) or evolutionary (e.g. selection for tolerant genotypes) mechanisms and thus avoid the loss of stability, as defined by the resistance of a process. Community tolerance to a novel stressor is expected to increase the resistance of key processes in stressed ecosystems. In freshwater communities we tested whether prolonged prior exposure to an environmental stressor, i.e. acidification, could increase ecosystem stability when the communities were exposed to a subsequent press perturbation of more severe acidification. As a measure of ecosystem stability, we quantified the diurnal variation in dissolved oxygen (DO), and the resistance of the DO cycle and phytoplankton biomass. High‐frequency data from oxygen loggers deployed in 12 mesocosms showed that severe acidification with sulfuric acid to pH 3 could cause a temporary (i.e. two‐week long) loss of diurnal variation in dissolved oxygen concentration. The loss of diurnal variation was accompanied by a strong reduction in phytoplankton biomass. However, the pre‐exposure to acidification for several weeks resulted in the maintenance of the diurnal cycle and higher levels of phytoplankton biomass, though they did not return to as rapidly to pre‐exposure functioning as non‐exposed mesocosms. These results suggest that ecosystem stability is intrinsically linked to community‐wide stress tolerance, and that a history of exposure to the stressor may increase resistance to it, though at the cost of some resilience.

Co-occurrence history increases ecosystem stability and resilience in experimental plant communities.

Understanding factors that maintain ecosystem stability is critical in the face of environmental change. Experiments simulating species loss from grassland have shown that losing biodiversity decreases ecosystem stability. However, as the originally sown experimental communities with reduced biodiversity develop, plant evolutionary processes or the assembly of interacting soil organisms may allow ecosystems to increase stability over time. We explored such effects in a long-term grassland biodiversity experiment with plant communities with either a history of co-occurrence (selected communities) or no such history (naïve communities) over a 4-yr period in which a major flood disturbance occurred. Comparing communities of identical species composition, we found that selected communities had temporally more stable biomass than naïve communities, especially at low species richness. Furthermore, selected communities showed greater biomass recovery after flooding, resulting in more stable post-flood productivity. In contrast to a previous study, the positive diversity-stability relationship was maintained after the flooding. Our results were consistent across three soil treatments simulating the presence or absence of co-selected microbial communities. We suggest that prolonged exposure of plant populations to a particular community context and abiotic site conditions can increase ecosystem temporal stability and resilience due to short-term evolution. A history of co-occurrence can in part compensate for species loss, as can high plant diversity in part compensate for the missing opportunity of such adaptive adjustments.

Coupling of green and brown food webs and ecosystem stability.

Ecosystems comprise living organisms and organic matter or detritus. In earlier community ecology theories, ecosystem dynamics were normally understood in terms of aboveground, green‐world trophic interaction networks, or food webs. Recently, there has been growing interest in the role played in ecosystem dynamics by detritus in underground, brown‐world interactions. However, the role of decomposers in the consumption of detritus to produce nutrients in ecosystem dynamics remains unclear. Here, an ecosystem model of trophic food chains, detritus, decomposers, and decomposer predators demonstrated that decomposers play a totally different role than that previously predicted, with regard to their relationship between nutrient cycling and ecosystem stability. The high flux of nutrients due to efficient decomposition by decomposers increases ecosystem stability. However, moderate levels of ecosystem openness (with movement of materials) can either greatly increase or decrease ecosystem stability. Furthermore, the stability of an ecosystem peaks at intermediate openness because open systems are less stable than closed systems. These findings suggest that decomposers and the food‐web dynamics of brown‐world interactions are crucial for ecosystem stability, and that the properties of decomposition rate and openness are important in predicting changes in ecosystem stability in response to changes in decomposition efficiency driven by climate change.

Stability of Afromontane ant diversity decreases across an elevation gradient

As the need to better understand the ecology of hotspots of endemism intensifies, the insurance hypothesis is drawing increasing attention from policy-makers and scenario-planners. The hypothesis states that biodiversity increases ecosystem stability. When species numbers fluctuate, there is potential for further perturbation, loss of function and increased opportunity for invasive species to fill vacated niches. Southern Africa is predicted to be disproportionately impacted by global change, and high altitude systems as foci of endemism are particularly vulnerable to warming. Using ants, a group key to ecosystem function, we assess effects of temperature, season, aspect, vegetation and soil conditions on montane ant species richness, stability of ant community composition, and stability of ant species richness across an altitude gradient. Over six consecutive years of bi-annual sampling, we gathered one of the largest standardized data sets to date. We showed for the first time that stability of ant species richness decreases with increasing altitude, whilst compositional similarity of ant communities is higher with increasing altitude. Findings reveal more similar, species-poor, less stable ant communities at high altitude at the same sites over time.

Climate mediates the biodiversity–ecosystem stability relationship globally

The insurance hypothesis, stating that biodiversity can increase ecosystem stability, has received wide research and political attention. Recent experiments suggest that climate change can impact how plant diversity influences ecosystem stability, but most evidence of the biodiversity-stability relationship obtained to date comes from local studies performed under a limited set of climatic conditions. Here, we investigate how climate mediates the relationships between plant (taxonomical and functional) diversity and ecosystem stability across the globe. To do so, we coupled 14 years of temporal remote sensing measurements of plant biomass with field surveys of diversity in 123 dryland ecosystems from all continents except Antarctica. Across a wide range of climatic and soil conditions, plant species pools, and locations, we were able to explain 73% of variation in ecosystem stability, measured as the ratio of the temporal mean biomass to the SD. The positive role of plant diversity on ecosystem stability was as important as that of climatic and soil factors. However, we also found a strong climate dependency of the biodiversity-ecosystem stability relationship across our global aridity gradient. Our findings suggest that the diversity of leaf traits may drive ecosystem stability at low aridity levels, whereas species richness may have a greater stabilizing role under the most arid conditions evaluated. Our study highlights that to minimize variations in the temporal delivery of ecosystem services related to plant biomass, functional and taxonomic plant diversity should be particularly promoted under low and high aridity conditions, respectively.

FORAGES AND PASTURES SYMPOSIUM: COVER CROPS IN LIVESTOCK PRODUCTION: WHOLE-SYSTEM APPROACH: Managing grazing to restore soil health and farm livelihoods.

To ensure long-term sustainability and ecological resilience of agroecosystems, agricultural production should be guided by policies to ensure regenerative cropping and grazing management protocols. Changing current unsustainable high-input agricultural practices to low-input practices that regenerate ecosystem function will be necessary for sustainable, resilient agroecosystems. Effective soil management provides the greatest potential for achieving sustainable use of agricultural land with rapidly changing, uncertain and variable climate. With appropriate management of grazing enterprises, soil function can be regenerated to improve essential ecosystem services and farm profitability. Affected ecosystem services include carbon sequestration, water infiltration, soil fertility, nutrient cycling, soil formation, biodiversity, wildlife habitat, and increased ecosystem stability and resilience. Collectively, conservation agriculture managed regeneratively supports ecologically healthy, resilient agroecosystems and enhances watershed function. To accomplish this, it is important for scientists to partner with farmers who have improved the environment and excel financially to convert experimental results into sound environmental, social, and economic benefits regionally and globally. Benefits include addressing questions at commercial scale; integrating component science into whole-system responses; identifying emergent properties and unintended consequences; incorporating pro-active management to achieve desired goals under changing circumstances; and including the potential of the human element to achieve superior economic and environmental goals. Developing and implementing regenerative management protocols that include ruminant grazing animals will be necessary to ensure long-term sustainability and ecological resilience of agroecosystems.

Precipitation alters interactions in a grassland ecological community.

Climate change is transforming precipitation regimes world-wide. Changes in precipitation regimes are known to have powerful effects on plant productivity, but the consequences of these shifts for the dynamics of ecological communities are poorly understood. This knowledge gap hinders our ability to anticipate and mitigate the impacts of climate change on biodiversity. Precipitation may affect fauna through direct effects on physiology, behaviour or demography, through plant-mediated indirect effects, or by modifying interactions among species. In this paper, we examined the response of a semi-arid ecological community to a fivefold change in precipitation over 7years. We examined the effects of precipitation on the dynamics of a grassland ecosystem in central California from 2007 to 2013. We conducted vegetation surveys, pitfall trapping of invertebrates, visual surveys of lizards and capture-mark-recapture surveys of rodents on 30 plots each year. We used structural equationmodelling to evaluate the direct, indirect and modifying effects of precipitation on plants, ants, beetles, orthopterans, kangaroo rats, ground squirrels and lizards. We found pervasive effects of precipitation on the ecological community. Although precipitation increased plant biomass, direct effects on fauna were often stronger than plant-mediated effects. In addition, precipitation altered the sign or strength of consumer-resource and facilitative interactions among the faunal community such that negative or neutral interactions became positive or vice versa with increasing precipitation. These findings indicate that precipitation influences ecological communities in multiple ways beyond its recognized effects on primary productivity. Stochastic variation in precipitation may weaken the average strength of biotic interactions over time, thereby increasing ecosystem stability and resilience to climate change.

Major histocompatibility complex diversity is positively associated with stream water temperatures in proximate populations of sockeye salmon.

Local adaptation to heterogeneous environments generates population diversity within species, significantly increasing ecosystem stability and flows of ecosystem services. However, few studies have isolated the specific mechanisms that create and maintain this diversity. Here, we examined the relationship between water temperature in streams used for spawning and genetic diversity at a gene involved in immune function [the major histocompatibility complex (MHC)] in 14 populations of sockeye salmon (Oncorhynchus nerka) sampled across the Wood River basin in south-western Alaska. The largest influence on MHC diversity was lake basin, but we also found a significant positive correlation between average water temperature and MHC diversity. This positive relationship between temperature and MHC diversity appears to have been produced by natural selection at very local scales rather than neutral processes, as no correlation was observed between temperature and genetic diversity at 90 neutral markers. Additionally, no significant relationship was observed between temperature variability and MHC diversity. Although lake basin was the largest driver of differences in MHC diversity, our results also demonstrate that fine-scale differences in water temperature may generate variable selection regimes in populations that spawn in habitats separated by as little as 1km. Additionally, our results indicated that some populations may be reaching a maximum level of MHC diversity. We postulate that salmon from populations in warm streams may delay spawning until late summer to avoid thermal stress as well as the elevated levels of pathogen prevalence and virulence associated with warm temperatures earlier in the summer.

Chapter 27 Cambrian–Ordovician cephalopod palaeogeography and diversity

Abstract Cephalopods have their earliest occurrence in Late Cambrian shallow-water carbonates on the North China Platform and rapidly dispersed across the globe within the latest Cambrian. Latest Cambrian and initial Ordovician cephalopod occurrences are restricted to the palaeotropical realm. The Ordovician records a unique morphological diversification and expansion of cephalopod habits and habitats which is expressed in a massive morphological diversification and unique palaeogeographical patterns of dispersal. The Ordovician cephalopod diversification was a complex process of appearance and disappearance of higher groups with a specific palaeogeographical signature and a clear selective component. A general Ordovician trend showed decreasing evolutionary turnover rates, increasing number of widespread genera, decreasing proportion of endemic genera, and decreasing beta-diversity. This is interpreted as a result of an increasing ecosystem stability during this time interval.

Stable Isotope Analysis Challenges Wasp-Waist Food Web Assumptions in an Upwelling Pelagic Ecosystem

Eastern boundary currents are often described as ‘wasp-waist’ ecosystems in which one or few mid-level forage species support a high diversity of larger predators that are highly susceptible to fluctuations in prey biomass. The assumption of wasp-waist control has not been empirically tested in all such ecosystems. This study used stable isotope analysis to test the hypothesis of wasp-waist control in the southern California Current large marine ecosystem (CCLME). We analyzed prey and predator tissue for δ13C and δ15N and used Bayesian mixing models to provide estimates of CCLME trophic dynamics from 2007–2010. Our results show high omnivory, planktivory by some predators, and a higher degree of trophic connectivity than that suggested by the wasp-waist model. Based on this study period, wasp-waist models oversimplify trophic dynamics within the CCLME and potentially other upwelling, pelagic ecosystems. Higher trophic connectivity in the CCLME likely increases ecosystem stability and resilience to perturbations.

Echinoderms Display Morphological and Behavioural Phenotypic Plasticity in Response to Their Trophic Environment

The trophic interactions of sea urchins are known to be the agents of phase shifts in benthic marine habitats such as tropical and temperate reefs. In temperate reefs, the grazing activity of sea urchins has been responsible for the destruction of kelp forests and the formation of ‘urchin barrens’, a rocky habitat dominated by crustose algae and encrusting invertebrates. Once formed, these urchin barrens can persist for decades. Trophic plasticity in the sea urchin may contribute to the stability and resilience of this alternate stable state by increasing diet breadth in sea urchins. This plasticity promotes ecological connectivity and weakens species interactions and so increases ecosystem stability. We test the hypothesis that sea urchins exhibit trophic plasticity using an approach that controls for other typically confounding environmental and genetic factors. To do this, we exposed a genetically homogenous population of sea urchins to two very different trophic environments over a period of two years. The sea urchins exhibited a wide degree of phenotypic trophic plasticity when exposed to contrasting trophic environments. The two populations developed differences in their gross morphology and the test microstructure. In addition, when challenged with unfamiliar prey, the response of each group was different. We show that sea urchins exhibit significant morphological and behavioural phenotypic plasticity independent of their environment or their nutritional status.