Long-term temporal and spatial variation of macrobenthos in the intertidal soft-bottom flats of two small bights (Chupa Inlet, Kandalaksha Bay, White Sea)

Despite the dynamic nature of spatial pattern, the temporal variation of spatial structure of marine benthic assemblages is rarely assessed using several temporal scales. We quantified the variability of density and biomass of main benthic species in the intertidal soft-bottom flats at two bights in Chupa Inlet (Kandalaksha Bay, the White Sea). The data cover the 21-year period (1987–2008) of a long-term monitoring survey (1987–present) using a hierarchical sampling design with two temporal (year, season within a year) and three spatial scales (bights—7 km, stations within a bight—10–100 m, and replicate samples—10 s cm apart). We used nested ANOVA to test significance and variance components to compare the relative contribution of different scales of variability of density and biomass of 18 most occurring macrobenthic species. Some species demonstrated high large-scale variability, however, the majority showed high small-scale variability and residual variance. The interactive variability was at least as important as the temporal effects, indicating that the spatial pattern changes through time. The assemblages were more variable at small scales and more stable at larger scales. Potential implications for sampling design are discussed.     

Marine biological community baselines in unimpacted tropical ecosystems: spatial and temporal analysis of reefs at Howland and Baker Islands

Howland and Baker Islands are two small, isolated reef and sand islets located near the equator in the central Pacific Ocean that are situated approximately 60 km apart. In 2004 and 2006, species-level monitoring at multiple sites, coupled with towed-diver surveys in 2002, 2004, and 2006 on both of these federally protected islands, revealed diverse fish, coral, macroinvertebrate, and algal assemblages. This study examines inter- and intra-island spatial and temporal differences in community composition among sites and presents baseline biological community parameters for two of the least impacted reef systems in the world. Despite similarities in species composition, permutational multivariate analysis of variance (PERMANOVA) and multidimensional scaling ordinations (nMDS) suggest biological communities at the two islands are distinct with Baker Island containing a greater percent cover of branched Acroporid corals and turf algae and Howland Island containing a greater percent cover of crustose coralline red algae and small, compact genera of coral. Both islands also contained considerable cover of non-invasive macroalgae. PERMANOVA further revealed benthic and fish species composition to differ between forereef and reef shelf sites from different sides of each island. When islands were considered as a whole, temporal changes were not noted between 2004 and 2006; however, temporal changes at select sites did occur, with coral cover decreasing significantly along the west side of Baker Island from 2004 to 2006.     

Spatiotemporal Patterns of Production Can Be Used to Detect State Change Across an Arid Landscape

Methods to detect and quantify shifts in the state of ecosystems are increasingly important as global change drivers push more systems toward thresholds of change. Temporal relationships between precipitation and aboveground net primary production (ANPP) have been studied extensively in arid and semiarid ecosystems, but rarely has spatial variation in these relationships been investigated at a landscape scale, and rarely has such information been viewed as a resource for mapping the distribution of different ecological states. We examined the broad-scale effects of a shift from grassland to shrubland states on spatiotemporal patterns of remotely sensed ANPP proxies in the northern Chihuahuan Desert. We found that the normalized difference vegetation index (NDVI), when averaged across an eight-year period, did not vary significantly between these states, despite changes in ecosystem attributes likely to influence water availability to plants. In contrast, temporal relationships between precipitation and time-integrated NDVI (NDVI-I) modeled on a per-pixel basis were sensitive to spatial variation in shrub canopy cover, a key attribute differentiating ecological states in the region. The slope of the relationship between annual NDVI-I and 2-year cumulative precipitation was negatively related to, and accounted for 71% of variation in, shrub canopy cover estimated at validation sites using high spatial resolution satellite imagery. These results suggest that remote sensing studies of temporal precipitation–NDVI relationships may be useful for deriving shrub canopy cover estimates in the region, as well as for mapping other ecological state changes characterized by shifts in long-term ANPP, plant functional type dominance, or both.     

Hard times for Italian coastal dunes: insights from a diachronic analysis based on random plots

Multi-year temporal studies are invaluable tools for monitoring changes in biodiversity through time. However, their applications in coastal ecosystems are still scarce. We investigated temporal trends in coastal dunes analyzing a set of 858 randomly-sampled georeferenced relevés performed between 2002 and 2015 along Central Italy’s sandy coastlines. Specifically, we explored changes in species richness and cover of targeted sandy habitats, we investigated trends in the cover of selected psammophilous native species and we assessed patterns of invasion by means of regression techniques. We observed a significant decrease in species richness and cover of the dune grasslands habitat. The species-level analysis confirmed a negative trend for two characteristic species of dune grasslands, Cutandia maritima and Medicago littoralis, while revealing a similar decline for Crucianella maritima and for Ammophila arenaria subsp. australis, key species of mobile dunes. The most striking trends emerged analyzing patterns in the cover of an invasive alien species, Carpobrotus sp., which showed a concerning increase in shifting dunes. In conclusion, our analyses reveal concerning changes involving dune grasslands, and at the same time hint at “early warnings” of degradation processes traceable in shifting dunes.     

Scenario simulations of future salinity and ecological consequences in the Baltic Sea and adjacent North Sea areas–implications for environmental monitoring

Substantial ecological changes occurred in the 1970s in the Northern Baltic during a temporary period of low salinity (S). This period was preceded by an episodic increase in the rainfall over the Baltic Sea watershed area. Several climate models, both global and regional, project an increase in the runoff of the Northern latitudes due to proceeding climate change. The aim of this study is to model, firstly, the effects on Baltic Sea salinity of increased runoff due to projected global change and, secondly, the effects of salinity change on the distribution of marine species. The results suggest a critical shift in the S range 5–7, which is a threshold for both freshwater and marine species distributions and diversity. We discuss several topics emphasizing future monitoring, modelling, and fisheries research. Environmental monitoring and modelling are investigated because the developing alternative ecosystems do not necessarily show the same relations to environment quality factors as the retiring ones. An important corollary is that the observed and modelled S changes considered together with species’ ranges indicate what may appear under a future climate. Consequences could include a shift in distribution areas of marine benthic foundation species and some 40–50 other species, affiliated to these. This change would extend over hundreds of kilometres, in the Baltic Sea and the adjacent North Sea areas. Potential cascading effects, in coastal ecology, fish ecology and fisheries would be extensive, and point out the necessity to develop further the “ecosystem approach in the environmental monitoring”.     

An approach to analysis of functional redundancy in protozoan communities for bioassessment in marine ecosystems

It is necessary to detect how much ecological redundancy or response units (RUs) exist in communities for reducing the “signal-to-noise” ratios of the observed full species data in community-based ecological research and monitoring programs. To reveal the functional redundancy in ciliated protozoan communities in marine ecosystems for both ecological research and monitoring programs, a multivariate approach (peeling procedure) was used to identify the response units to the environmental changes using a dataset of biofilm-dwelling ciliates from coastal waters of the Yellow Sea, northern China. From the full 141-species dataset, three subsets with sufficient information of the whole community (correlation coefficient >0.75) were identified as response units (RUs 1–3) at three levels of functional redundancy, which comprised 20, 26 and 27 species, respectively. These response units appeared to be interchangeable between functional equivalents on both spatial and temporal scales. In terms of relative abundance, RU1, which predominated the ciliate communities over 1-year period, and RU2, which occurred only in warm seasons (except winter) with a peak in summer, presented a decreasing trend, while RU3, which distributed all four seasons with two peaks in summer and autumn, increased with the increase of pollution level. Furthermore, high proportions of bacterivores were found in RU1 during warm seasons and represented an increase trend, while high relative abundances of algivores occurred in RUs 2 and 3 appeared to be decreasing along the pollution gradient. These results demonstrated that the ciliated protozoan assemblages have high functional redundancy in response to environmental changes in marine ecosystems.     

Bioindicators of changes in water quality on coral reefs: review and recommendations for monitoring programmes

Effective environmental management requires monitoring programmes that provide specific links between changes in environmental conditions and ecosystem health. This article reviews the suitability of a range of bioindicators for use in monitoring programmes that link changes in water quality to changes in the condition of coral-reef ecosystems. From the literature, 21 candidate bioindicators were identified, whose responses to changes in water quality varied spatially and temporally; responses ranged from rapid (hours) changes within individual corals to long-term (years) changes in community composition. From this list, the most suitable bioindicators were identified by determining whether responses were (i) specific, (ii) monotonic, (iii) variable, (iv) practical and (v) ecologically relevant to management goals. For long-term monitoring programmes that aim to quantify the effects of chronic changes in water quality, 11 bioindicators were selected: symbiont photophysiology, colony brightness, tissue thickness and surface rugosity of massive corals, skeletal elemental and isotopic composition, abundance of macro-bioeroders, micro- and meiobenthic organisms such as foraminifera, coral recruitment, macroalgal cover, taxonomic richness of corals and the maximal depth of coral-reef development. For short-term monitoring programmes, or environmental impact assessments that aim to quantify the effects of acute changes in water quality, a subset of seven of these bioindicators were selected, including partial mortality. Their choice will depend on the specific objectives and the timeframe available for each monitoring programme. An assessment framework is presented to assist in the selection of bioindicators to quantify the effects of changing water quality on coral-reef ecosystems.     

Fine-scale time series surveys reveal new insights into spatio-temporal trends in coral cover (2002–2018), of a coral reef on the Southern Great Barrier Reef

Reef monitoring programmes often focus on limited sites, predominantly on reef slope areas, which do not capture compositional variability across zones. This study assessed spatial and temporal changes in hard coral cover at four hierarchical spatial scales. ~ 55,000, geo-referenced photoquadrats were collected annually from 2002 to 2018 and analysed using artificial intelligence for 31 sites across reef flat and reef slope zones on Heron Reef, Southern Great Barrier Reef, Australia. Trends in hard coral cover were examined at three spatial scales: (1) “reef scale”, all data; (2) “geomorphic zone scale”—north/south reef slope, inner/outer reef flat; and (3) “site scale”—31 sites. Coral cover trajectories were also examined at: (4) “sub-site scale”—sub-division of sites into 567 sub-sites, to estimate variability in coral cover trajectories via spatial statistical modelling. At reef scale coral cover increased over time to 25.6 ± 0.4 SE % in 2018 but did not recover following disturbances caused by disease (2004–2008), cyclonic conditions (2009) or severe storms (2015) to the observed pre-disturbance level (44.0 ± 0.7 SE %) seen in 2004. At geomorphic zone scale, the reef slope had significantly higher coral cover than the reef flat. Trends of decline and increase were visible in the slope zones, and the southern slope recovered to pre-decline levels. Variable coral cover trends were visible at site scale. Furthermore, sub-site spatial modelling captured eight years of coral recovery that occurred at different times and magnitudes across the four geomorphic zones, effectively estimating variability in the trajectory of the reef’s coral community. Derived spatial predictions for the entire reef show patchy coral recovery, particularly on the southern slope, and that recovery hotspots are distributed across the reef. These findings suggest that to fully understand and interpret coral decline or recovery on a reef, more accurate assessment can be achieved by examining sites distributed within different geomorphic zones to capture variation in exposure, depth and consolidation.

     

Assessing functional redundancy in chronically trawled benthic communities

Fishing disturbance on ecosystems leads to changes in community structure and composition, which may have drastic implications for ecosystem functional performance. Functional redundancy, defined as species sharing similar functional roles, is a community property that plays an important role in preventing functional changes in ecosystems under pressure. In this study, we suggest that functional redundancy may be achieved through trait abundance (i.e. large amounts of a trait, hereafter “common traits”), or through trait richness (i.e. large numbers of distinct taxa exhibiting the same trait, hereafter “widespread traits”). We assessed the variability of both measures obtained from epifaunal and infaunal communities in soft-bottom trawling grounds. Sampling sites were located in four Mediterranean areas that were subjected to different levels of trawling effort. Common and widespread traits measures were based on the analysis of biological traits linked to key soft-bottoms functions such as nutrient cycling, bentho-pelagic coupling and habitat provision. The role of rare species in both measures was also assessed and we observed that, in our study sites, rare species generally exhibited the same traits as the most abundant species. Common and widespread traits measures provided complementary information on benthic functional redundancy. Thus, we suggest that a combination of the two measures should be used to appropriately assess benthic functional redundancy in trawling grounds. As redundancy is a component of ecosystem resilience, functional redundancy evaluation is important to assess the overall integrity of ecosystems.     

Nearshore subtidal community structure compared between inner coast and outer coast sites in Southeast Alaska

Processes that structure subarctic marine communities, particularly in glaciated regions, are not well understood. This understanding is needed as a baseline and to manage these communities in the face of future climate-driven changes. This study investigates two coastal regions of Southeast Alaska with the goals to (a) identify and compare patterns of subtidal community structure for macroalgal, fish, macroinvertebrate (>5?cm), and small epibenthic invertebrate (<5?cm) communities between inner coast and outer coast sites and (b) link patterns of community structure to habitat and environmental parameters. Species assemblage and benthic habitat data were used to compare species diversity and community composition at 6?m and 12?m depths at nine inner coast and nine outer coast sites. Multivariate analysis was applied to reduce environmental variables to major gradients, to resolve community structure, and to relate community structure to habitat and environmental variables. Increased salinity and decreased temperature at outer coast sites compared with inner coast sites were associated with community structure, with greater species diversity at outer coast sites at 6?m depth. Invertebrate community composition was associated with benthic habitat, including crust and coralline algae for macroinvertebrates, and algal cover and substrate for small epibenthic invertebrates. This research suggests that marine communities in glaciated regions are strongly influenced by freshwater input and that future climate-driven changes in freshwater input will likely result in marine community composition changes.     

Spatial and temporal population genetic structure of four northeastern Pacific littorinid gastropods: the effect of mode of larval development on variation at one mitochondrial and two nuclear DNA markers

We investigated the effect of development mode on the spatial and temporal population genetic structure of four littorinid gastropod species. Snails were collected from the same three sites on the west coast of Vancouver Island, Canada in 1997 and again in 2007. DNA sequences were obtained for one mitochondrial gene, cytochrome b ( Cyt b ), and for up to two nuclear genes, heat shock cognate 70 ( HSC70 ) and aminopeptidase N intron ( APN54 ). We found that the mean level of genetic diversity and long-term effective population sizes ( N _e) were significantly greater for two species, Littorina scutulata and L. plena , that had a planktotrophic larval stage than for two species, Littorina sitkana and L. subrotundata , that laid benthic egg masses which hatched directly into crawl-away juveniles. Predictably, two poorly dispersing species, L. sitkana and L. subrotundata , showed significant spatial genetic structure at an 11- to 65-km geographical scale that was not observed in the two planktotrophic species. Conversely, the two planktotrophic species had more temporal genetic structure over a 10-year interval than did the two direct-developing species and showed highly significant temporal structure for spatially pooled samples. The greater temporal genetic variation of the two planktotrophic species may have been caused by their high fecundity, high larval dispersal, and low but spatially correlated early survivorship. The sweepstakes-like reproductive success of the planktotrophic species could allow a few related females to populate hundreds of kilometres of coastline and may explain their substantially larger temporal genetic variance but lower spatial genetic variance relative to the direct-developing species.     

Consequences of ignoring spatial variation in population trend when conducting a power analysis

Long‐term, large‐scale monitoring programs are becoming increasingly common to document status and trends of wild populations. A successful program for monitoring population trend hinges on the ability to detect the trend of interest. Power analyses are useful for quantifying the sample size needed for trend detection, given expected variation in the population. Four components of variation (within‐year variation at a given site, interannual variation within a site, variation among sites in the interannual variation, and variation among sites in mean abundance or density) are commonly considered in power analyses for population trend, but a fifth is rarely considered: variation among sites in the local trend. Spatial variation in trend is expected to reduce statistical power, but the magnitude of this reduction has not been fully explored. We used computer simulations to evaluate the consequences of ignoring spatial variation in trend under a variety of sampling designs and wide ranges of other components of variation. The effect of spatial variation in trend on power was minor when other input parameters took extreme values that made the trend either very difficult or very easy to detect. However, at moderate values of the other parameters, spatial variation in trend had a strong effect, reducing statistical power by up to 60%. In some cases, ignoring spatial variation in trend resulted in an 80% probability of a type I error (falsely detecting a trend in a stable population). Spatial variation in trend is therefore an important consideration when designing a long‐term monitoring program for many species, especially those affected by local conditions at sites that are repeatedly surveyed. If variation in trend is ignored, as in many previous power analyses, the recommended sampling design will likely be insufficient to detect the trend of interest and lead to potentially false conclusions of a stable population.     

Reproducibility of species lists,visual cover estimates and frequency methods for recording high‐mountain vegetation

Question: When multiple observers record the same spatial units of alpine vegetation, how much variation is there in the records and what are the consequences of this variation for monitoring schemes to detect changes? Location: One test summit in Switzerland (Alps) and one test summit in Scotland (Cairngorm Mountains). Method: Eight observers used the GLORIA protocols for species composition and visual cover estimates in percentages on large summit sections (>100 m²) and species composition and frequency in nested quadrats (1 m²). Results: The multiple records from the same spatial unit for species composition and species cover showed considerable variation in the two countries. Estimates of pseudo‐turnover of composition and coefficients of variation of cover estimates for vascular plant species in 1 m × 1‐m quadrats showed less variation than in previously published reports, whereas our results in larger sections were broadly in line with previous reports. In Scotland, estimates for bryophytes and lichens were more variable than for vascular plants. Conclusions: Statistical power calculations indicated that unless large numbers of plots were used, changes in cover or frequency were only likely to be detected for abundant species (exceeding 10% cover) or if relative changes were large (50% or more). Lower variation could be reached with the point method and with larger numbers of small plots. However, as summits often strongly differ from each other, supplementary summits cannot be considered as a way of increasing statistical power without introducing a supplementary component of variance into the analysis and hence into the power calculations.     

Measuring the synanthropy of species and communities to monitor the effects of urbanization on biodiversity

Urbanization is considered as one of the most important land-use and land-cover (LULC) changes with multiple pervasive effects on biodiversity. However, the quantitative assessment of biodiversity responses to urbanization remains challenging because some species can be directly and negatively affected by the spread of human settlements, while others can benefit from this LULC change. Moreover, although species sensitivity to urban settlements (their “synanthropy”) can either correspond to the spatial segregation of individuals within urban habitats or to their positive temporal trends in these habitats, these two facets are hardly distinguished explicitly. Here, we confronted the fine-scale spatial distribution of all the buildings in France with the spatial distribution and population trends of the 119 most common French breeding birds monitored in 2124 plots from 2001 to 2012. We developed and tested two indicators of “synanthropy”. The first indicator (S1) differentiates species along a continuous gradient from urban “avoiders” (low S1) to urban “dwellers” (high S1). The second indicator measures the beneficial or detrimental effect of building densities on the temporal trends of the populations. It allows the segregation among urban “losers” having lower temporal trends with increasing buildings (low S2) from urban “winners” (high S2) having more positive trends in more urbanized areas. We then tested the relationships between S1 and S2 with a set of species and life history traits. Finally, we transposed these species indicators to communities using community weighted means to test the link between the synanthropy of communities with bird species richness, and the spatial, temporal and spatio-temporal trends of the synanthropy of bird communities. We found that 43% of the species were “urban dwellers”, and 18% “urban winners”. Both urban dwellers and winners were species widely distributed and locally abundant. Urban dwellers were mainly ground feeders but did not nest on the ground. At the community level, high species richness was associated with medium-values of community synanthropy, following the intermediate-disturbance hypothesis. We found that the average value of community synanthropy and their trend were not randomly distributed in space. These two indicators of synanthropy can be used in different taxonomic groups and areas to assess the proportion of synanthropic species within communities, to monitor their temporal trends and their spatial distribution and represent a straightforward complement to the synthetic indicators of human footprint on biodiversity.     

Understanding the Spatio-Temporal Response of Coral Reef Fish Communities to Natural Disturbances: Insights from Beta-Diversity Decomposition

Understanding how communities respond to natural disturbances is fundamental to assess the mechanisms of ecosystem resistance and resilience. However, ecosystem responses to natural disturbances are rarely monitored both through space and time, while the factors promoting ecosystem stability act at various temporal and spatial scales. Hence, assessing both the spatial and temporal variations in species composition is important to comprehensively explore the effects of natural disturbances. Here, we suggest a framework to better scrutinize the mechanisms underlying community responses to disturbances through both time and space. Our analytical approach is based on beta diversity decomposition into two components, replacement and biomass difference. We illustrate this approach using a 9-year monitoring of coral reef fish communities off Moorea Island (French Polynesia), which encompassed two severe natural disturbances: a crown-of-thorns starfish outbreak and a hurricane. These disturbances triggered a fast logistic decline in coral cover, which suffered a 90% decrease on all reefs. However, we found that the coral reef fish composition remained largely stable through time and space whereas compensatory changes in biomass among species were responsible for most of the temporal fluctuations, as outlined by the overall high contribution of the replacement component to total beta diversity. This suggests that, despite the severity of the two disturbances, fish communities exhibited high resistance and the ability to reorganize their compositions to maintain the same level of total community biomass as before the disturbances. We further investigated the spatial congruence of this pattern and showed that temporal dynamics involved different species across sites; yet, herbivores controlling the proliferation of algae that compete with coral communities were consistently favored. These results suggest that compensatory changes in biomass among species and spatial heterogeneity in species responses can provide further insurance against natural disturbances in coral reef ecosystems by promoting high levels of key species (herbivores). They can also allow the ecosystem to recover more quickly.     

Adaptive Long-Term Monitoring of Soil Health in Metal Phytostabilization: Ecological Attributes and Ecosystem Services Based on Soil Microbial Parametersxs

Phytostabilization is a promising option for the remediation of metal contaminated soils which requires the implementation of long-term monitoring programs. We here propose to incorporate the paradigm of “adaptive monitoring”, which enables monitoring programs to evolve iteratively as new information emerges and research questions change, to metal phytostabilization. Posing good questions that cover the chemical, toxicological and ecological concerns associated to metal contaminated soils is critical for an efficient long-term phytostabilization monitoring program. Regarding the ecological concerns, soil microbial parameters are most valuable indicators of the effectiveness of metal phytostabilization processes in terms of recovery of soil health. We suggest to group soil microbial parameters in higher-level categories such as “ecological attributes” (vigor, organization, stability) or “ecosystem services” in order to facilitate interpretation and, most importantly, to provide long-term phytostabilization monitoring programs with the required stability through time against changes in techniques, methods, interests, etc. that will inevitably occur during the monitoring program. Finally, a Phytostabilization Monitoring Card, based on both ecological attributes and ecosystem services, for soil microbial properties is provided.     

Spatial and temporal variability in species richness in a temperate intertidal community

Understanding changes in estuarine benthic communities has important implications for conservation and yet it is a challenge due to the high natural variability of these systems. We addressed this challenge through the study of temporal and spatial patterns of species richness in an intertidal benthic community in New Zealand North Island. Five different locations within the estuary were monitored seasonally over 12 yr. This data set allowed the study of species–time–area relationships (STAR) and the delineation of patterns in species richness, heterogeneity and turnover in space and time. The site with the highest species richness also had the highest within‐site heterogeneity in species richness, a high number of species occurring infrequently in time, the lowest mud content and the most variable wave climate. Similarities and differences between sites were generally maintained over time, although seasonal and multi‐year patterns in species richness occurred at all sites. The STAR showed a significant negative interaction between space and time, with species accumulation rates in space and time being equivalent at 4 spatial replicates (250 m²) and 2 temporal replicates (6 months). The lowest source of variability in species turnover was within site, and the highest source was over years. This was reflected in the lack of an asymptotic relationship in the species accumulation curve despite the 12 yr of monitoring. These results contribute to the knowledge of the variability in diversity patterns in estuaries and have important implications for long‐term monitoring of natural communities and the estimation of diversity for conservation.     

Forest floor vegetation response to nitrogen deposition in Europe

Chronic nitrogen (N) deposition is a threat to biodiversity that results from the eutrophication of ecosystems. We studied long‐term monitoring data from 28 forest sites with a total of 1,335 permanent forest floor vegetation plots from northern Fennoscandia to southern Italy to analyse temporal trends in vascular plant species cover and diversity. We found that the cover of plant species which prefer nutrient‐poor soils (oligotrophic species) decreased the more the measured N deposition exceeded the empirical critical load (CL) for eutrophication effects (P = 0.002). Although species preferring nutrient‐rich sites (eutrophic species) did not experience a significantly increase in cover (P = 0.440), in comparison to oligotrophic species they had a marginally higher proportion among new occurring species (P = 0.091). The observed gradual replacement of oligotrophic species by eutrophic species as a response to N deposition seems to be a general pattern, as it was consistent on the European scale. Contrary to species cover changes, neither the decrease in species richness nor of homogeneity correlated with nitrogen CL exceedance (ExCL_empN). We assume that the lack of diversity changes resulted from the restricted time period of our observations. Although existing habitat‐specific empirical CL still hold some uncertainty, we exemplify that they are useful indicators for the sensitivity of forest floor vegetation to N deposition.     

Spatio-temporal dynamics of multi-trophic communities reveal ecosystem-wide functional reorganization

Large-scale alterations in marine ecosystems as a response to environmental and anthropogenic pressures have been documented worldwide. Yet, these are primarily investigated by assessing abundance fluctuations of a few dominant species, which inadequately reflect ecosystem-wide changes. In addition, it is increasingly recognized that it is not species identity per se, but their traits that determine environmental responses, biological interactions and ecosystem functioning. In this study, we investigated long-term, spatio-temporal variability in trait composition across multiple organism groups to assess whether functional changes occur in a similar way across trophic levels and whether shifts in trait composition link to environmental change. We combined extensive trait datasets with long-term surveys (30–40 yr) of four organism groups (phytoplankton, zooplankton, benthic invertebrates and fish) in three environmentally distinct areas of a large marine ecosystem. We found similar temporal trajectories in the community weighted mean trait time-series of the different trophic groups, revealing ecosystem-wide functional changes. The traits involved and their dynamics differed between areas, concurrent with climate-driven changes in temperature and salinity, as well as more local dynamics in nutrients and oxygen. This finding highlights the importance of considering both global climate, as well as local external drivers when studying ecosystem changes. Using a multi-trophic trait-based approach, our study demonstrates the importance of integrating community functional dynamics across multiple trophic levels to capture ecosystem-wide responses which could, ultimately, help moving towards a holistic understanding, assessment and management of marine ecosystems.     

Temporal patterns in coral reef, seagrass and mangrove communities from Chengue bay CARICOMP site (Colombia): 1993-2008

Few monitoring programs have simultaneously assessed the dynamics of linked marine ecosystems (coral reefs, seagrass beds and mangroves) to document their temporal and spatial variability. Based on CARICOMP protocol we evaluated permanent stations in coral reefs, seagrass beds and mangroves from 1993 to 2008 in Chengue Bay at the Tayrona Natural Park, Colombian Caribbean. Overall, the studied ecosystems showed a remarkable stability pattern over the monitoring period. While there were annual variations in coral reefs (coral cover) and mangroves (litterfall) caused by hurricane Lenny in 1999, particular trends in seagrass (leaf area index and leaf productivity) appear to reflect the natural variability in this ecosystem. We suggest that monitoring sites at the three marine ecosystems had in general a healthy development in the last 16 years. Our results are critical to locally improve the management strategies (Tayrona Natural Park) and to understand the long-term dynamics of closely associated marine ecosystems in the Caribbean.