Differential response of nematode colonist communities to the intertidal placement of dredged material

The use of fine-grained maintenance dredged material for habitat enhancement has increased in recent years, particularly recharge schemes which provide a means of combating the erosion of intertidal flats and saltmarsh. This article investigates the development of meiofaunal nematode communities following a natural experiment in 2003, when fine-grained dredged material was deposited concurrently at four adjacent intertidal recharge sites on the southeast coast of the United Kingdom. A 12-month survey of nematode assemblages was carried out to compare univariate, multivariate, allometric and functional attributes of colonist communities in relation to the different environmental conditions prevailing at the four sites. Developing assemblages were increasingly affected by the spatial differences in the elevation, consolidation and exposure of bed material. The results indicated that the colonisation sequence was the result of random settling of suspended nematodes, sequential reproduction and differential survival and reproductive success of colonising species. For the first time, this experiment provided insights into the development of adaptive and functional types of meiofaunal nematodes following the intertidal deposition of uncontaminated fine-grained dredged material. This, in turn, will contribute considerably to the development of ecological models of the evolution of the large-scale placement of muddy dredged material in the intertidal environment.     

On the edge: The use of infrared thermography in monitoring responses of intertidal organisms to heat stress

Monitoring changes in the environment and the corresponding effects on biological systems still represents a major challenge in many marine and terrestrial ecological studies. Infrared thermography (IRT), and its application within the marine environment, represents an effective non-invasive tool for measuring the temperatures of organisms and their surrounding environment in situ. The use of IRT within the intertidal zone is particularly useful since habitat and organismal temperatures are highly variable across both fine spatial and temporal scales. We review the growing number of intertidal studies that utilise IRT to investigate the role of small-scale temperature variability in contributing to various demographic and ecological processes. In particular, we introduce two indicators of the thermal quality of intertidal habitats that can be readily used by ecologists but also management and conservation policy makers to assess the suitability of a given habitat for a range of species under actual and predicted climatic conditions. We also outline a range of potential applications involving IRT that have yet to be explored for monitoring coastal environments. These include combining photogrammetry, unmanned aerial vehicles and IRT to large-scale three-dimensional thermal maps of intertidal habitats. We also suggest ways in which this technology could facilitate environmental management objectives in a warming world, such as the identification and quantification of thermal refugia across various spatial and temporal scales. We affirm with previous studies that such thermal refugia are vital for the adaptation of intertidal communities to climate change and that IRT could facilitate more effective management and conservation of these areas. The IRT applications outlined in this review are by no means exhaustive or limited to rocky intertidal environments. We envision that IRT will become increasingly popular as environmental management agencies become increasingly concerned about global climate change and how to combat its negative consequences on ecosystems.     

A marine protected area network does not confer community structure resilience to a marine heatwave across coastal ecosystems

Marine protected areas (MPAs) have gained attention as a conservation tool for enhancing ecosystem resilience to climate change. However, empirical evidence explicitly linking MPAs to enhanced ecological resilience is limited and mixed. To better understand whether MPAs can buffer climate impacts, we tested the resistance and recovery of marine communities to the 2014–2016 Northeast Pacific heatwave in the largest scientifically designed MPA network in the world off the coast of California, United States. The network consists of 124 MPAs (48 no-take state marine reserves, and 76 partial-take or special regulation conservation areas) implemented at different times, with full implementation completed in 2012. We compared fish, benthic invertebrate, and macroalgal community structure inside and outside of 13 no-take MPAs across rocky intertidal, kelp forest, shallow reef, and deep reef nearshore habitats in California's Central Coast region from 2007 to 2020. We also explored whether MPA features, including age, size, depth, proportion rock, historic fishing pressure, habitat diversity and richness, connectivity, and fish biomass response ratios (proxy for ecological performance), conferred climate resilience for kelp forest and rocky intertidal habitats spanning 28 MPAs across the full network. Ecological communities dramatically shifted due to the marine heatwave across all four nearshore habitats, and MPAs did not facilitate habitat-wide resistance or recovery. Only in protected rocky intertidal habitats did community structure significantly resist marine heatwave impacts. Community shifts were associated with a pronounced decline in the relative proportion of cold water species and an increase in warm water species. MPA features did not explain resistance or recovery to the marine heatwave. Collectively, our findings suggest that MPAs have limited ability to mitigate the impacts of marine heatwaves on community structure. Given that mechanisms of resilience to climate perturbations are complex, there is a clear need to expand assessments of ecosystem-wide consequences resulting from acute climate-driven perturbations, and the potential role of regulatory protection in mitigating community structure changes.     

Coastal marine habitats harbor novel early-diverging fungal diversity

Despite nearly a century of study, the diversity of marine fungi remains poorly understood. Historical surveys utilizing microscopy or culture-dependent methods suggest that marine fungi are relatively species-poor, predominantly Dikarya, and localized to coastal habitats. However, the use of high-throughput sequencing technologies to characterize microbial communities has challenged traditional concepts of fungal diversity by revealing novel phylotypes from both terrestrial and aquatic habitats. Here, I used ion semiconductor sequencing (Ion Torrent) of the ribosomal large subunit (LSU/28S) to explore fungal diversity from water and sediment samples collected from four habitats in coastal North Carolina. The dominant taxa observed were Ascomycota and Chytridiomycota, though all fungal phyla were represented. Diversity was highest in sand flats and wetland sediments, though benthic sediments harbored the highest proportion of novel sequences. Most sequences assigned to early-diverging fungal groups could not be assigned beyond phylum with statistical support, suggesting they belong to unknown lineages.     

Quantifying the trophic base for benthic secondary production in the Nakdong River estuary of Korea using stable C and N isotopes

The overall dependence of benthic secondary production on the main primary producers at three different habitats in the Nakdong River estuarine system, Korea, was estimated. Inventories of macrobenthic invertebrate biomass were combined with multiple-isotope-mixing models to evaluate the trophic base, comparing Scirpus triqueter-dominated and Phragmites australis-dominated marshes and bare intertidal flat. The feasible contributions of four main food sources, marsh macrophytes, the microphytobenthos, and riverine and marine suspended particulate organic matter (RPOM and MPOM), to the consumer biomasses were calculated using the isotopic mixing model. After weighting the feasible contributions of food sources to each taxon by the consumer biomass, the resultant values were summed for all the consumers at each habitat to quantify the trophic base of the benthic invertebrate community. Dual-isotope-mixing model calculations verified the varying dependence on those potential food sources among the functional feeding groups. In addition, the dependence on each source of the same functional group varied between bare intertidal and salt-marsh habitats, shifting from a dominance of benthic and pelagic microalgal sources on the former habitat to a mixed food source at the latter habitat. The biomasses of the species comprising each functional group differed among habitats and sampling dates, so that each functional group made a different contribution to the whole benthic community and its basal food source. Given the calculation of the overall dependence of macrozoobenthic community on each food source, our results indicate that the microphytobenthic source dominates (nearly half) the trophic base in all the intertidal habitats of different vegetational compositions. Marsh-macrophyte-derived organic matter and RPOM served as considerable subsidies only to salt-marsh food webs, reflecting the use of the mixed food source by salt-marsh-bed consumers. Conversely, the dominance of MPOM in the total food base was equal to that of the microphytobenthos in the bare intertidal ecosystem but increased during spring−summer in the salt-marsh systems. Our results also suggest that the river discharge concentrated during the summer monsoon does not lead to any shift in trophic base for estuarine secondary production.     

Climate drivers of diatom distribution in shallow subarctic lakes

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Redistribution of the lizardfish Harpadon nehereus in coastal waters of China due to climate change

Climate change has the potential to greatly alter species distributions and threatens biodiversity in marine ecosystems. Mapping changes in species distribution patterns under climate change will help facilitate management strategies to maintain ecosystem structure and function. The lizardfish Harpadon nehereus is an aggressive predator that has experienced rapid population growth along the coast of China in recent decades, compressing the ecological niches of other marine species and disrupting food webs. If this species’ range is shifting due to climate change, it could further impact the integrity of ecological communities. To map the distribution of H. nehereus, we developed an ensemble species distribution model and projected the present and future habitat suitability in Chinese coastal waters. Annual mean benthic water temperature was identified as the most important variable affecting the projected distribution of H. nehereus, followed by water depth and salinity. Currently suitable habitats are along the coast from Guangxi Province to the southern Jiangsu Province. As climate changes, the southern portion of its distribution is predicted to recede with habitat losses, and the overall suitable habitat will shift northward. To avoid the potential impacts of H. nehereus redistribution, precautionary management based on species distribution modeling would help to maintain healthy marine ecosystems in the newly invaded areas.

     

Prey Distribution,Physical Habitat Features,and Guild Traits Interact to Produce Contrasting Shorebird Assemblages among Foraging Patches

Worldwide declines in shorebird populations, driven largely by habitat loss and degradation, motivate environmental managers to preserve and restore the critical coastal habitats on which these birds depend. Effective habitat management requires an understanding of the factors that determine habitat use and value to shorebirds, extending from individuals to the entire community. While investigating the factors that influenced shorebird foraging distributions among neighboring intertidal sand flats, we built upon species-level understandings of individual-based, small-scale foraging decisions to develop more comprehensive guild- and community-level insights. We found that densities and community composition of foraging shorebirds varied substantially among elevations within some tidal flats and among five flats despite their proximity (all located within a 400-m stretch of natural, unmodified inlet shoreline). Non-dimensional multivariate analyses revealed that the changing composition of the shorebird community among flats and tidal elevations correlated significantly (ρ_s = 0.56) with the spatial structure of the benthic invertebrate prey community. Sediment grain-sizes affected shorebird community spatial patterns indirectly by influencing benthic macroinvertebrate community compositions. Furthermore, combining sediment and macroinvertebrate information produced a 27% increase in correlation (ρ_s = 0.71) with shorebird assemblage patterns over the correlation of the bird community with the macroinvertebrate community alone. Beyond its indirect effects acting through prey distributions, granulometry of the flats influenced shorebird foraging directly by modifying prey availability. Our study highlights the importance of habitat heterogeneity, showing that no single patch type was ideal for the entire shorebird community. Generally, shorebird density and diversity were greatest at lower elevations on flats when they became exposed; these areas are at risk from human intervention by inlet sand mining, construction of groins and jetties that divert sediments from flats, and installation of seawalls on inlet shorelines that induce erosion of flats.     

Contribution of unvegetated tidal flats to coastal carbon flux

Unvegetated flats occupy a large area in the intertidal zone. However, compared to vegetated areas, the carbon sequestration of unvegetated tidal flats is rarely quantified, even though these areas are highly threatened by human development and climate change. We determined benthic maximum gross primary production (GPP_m), net primary production (NPP) and total respiration (TR) during emersion on seven tidal flats along a latitudinal gradient (from 22.48°N to 40.60°N) in winter and summer from 2012 to 2016 to assess the spatial and temporal variability of carbon dioxide flux. In winter, these processes decreased by 89%–104% towards higher latitudes. In summer, however, no clear trend was detected across the latitudinal gradient. Quadratic relationships between GPP_m, NPP and TR and sediment temperature can be described along the latitudinal gradient. These curves showed maximum values of GPP_m and NPP when the sediment temperatures reached 28.7 and 26.6°C respectively. TR increased almost linearly from 0 to 45°C. The maximum daily NPP across the latitudinal gradient averaged 0.24 ± 0.28 g C m^?2 day^?1, which was only 10%–20% of the global average of NPP of vegetated coastal habitats. Multiplying with the global area of unvegetated tidal flats, our results suggest that the contribution of NPP on unvegetated tidal flats to the coastal carbon cycle is small (11.04 ± 13.32 Tg C/year). If the land cover of vegetated habitats is continuously degraded to unvegetated tidal flats, the carbon sequestration capacity in the intertidal zone is expected to reduce by at least 13.10 Tg C/year, equivalent to 1% of global carbon emissions from land‐use change.     

Geographical variation in the use of intertidal rocky shores by the lizard Microlophus atacamensis in relation to changes in terrestrial productivity along the Atacama Desert coast

1. The movement of materials and organisms between ecosystems is a common process in nature. 2. In the present study we investigate the hypothesis that the movement of consumers between ecosystems depends not only on the differences in productivity between ecosystems and prey availability, but also on these animals' biological characteristics. 3. To address this hypothesis we investigated the changes in abundance, habitat utilization and diet of the lizard Microlophus atacamensis along its geographical range on the coast of the Atacama Desert. Within this range, intertidal rocky shore communities do not show important variations in their species composition and abundance, but terrestrial communities show a steep gradient of productivity associated with the increase in rainfall from north to south. 4. Our results show that the use of intertidal habitats and the consumption of intertidal prey by M. atacamensis change within its geographical range: in the North, the species uses intertidal areas and behaves as an herbivore consuming mostly algae, whereas in the South it expends most of the time in terrestrial habitats as a carnivore mainly of arthropods. 5. Our study gives new evidence for cross-ecosystem connections created by consumer movement between habitats of contrasting but variable productivity levels.     

Multiple habitat use by declining migratory birds necessitates joined‐up conservation

Many species depend on multiple habitats at different points in space and time. Their effective conservation requires an understanding of how and when each habitat is used, coupled with adequate protection. Migratory shorebirds use intertidal and supratidal wetlands, both of which are affected by coastal landscape change. Yet the extent to which shorebirds use artificial supratidal habitats, particularly at highly developed stopover sites, remains poorly understood leading to potential deficiencies in habitat management. We surveyed shorebirds on their southward migration in southern Jiangsu, a critical stopover region in the East Asian Australasian Flyway (EAAF), to measure their use of artificial supratidal habitats and assess linkages between intertidal and supratidal habitat use. To inform management, we examined how biophysical features influenced occupancy of supratidal habitats, and whether these habitats were used for roosting or foraging. We found that shorebirds at four of five sites were limited to artificial supratidal habitats at high tide for ~11–25 days per month because natural intertidal flats were completely covered by seawater. Within the supratidal landscape, at least 37 shorebird species aggregated on artificial wetlands, and shorebirds were more abundant on larger ponds with less water cover, less vegetation, at least one unvegetated bund, and fewer built structures nearby. Artificial supratidal habitats were rarely used for foraging and rarely occupied when intertidal flats were available, underscoring the complementarity between supratidal roosting habitat and intertidal foraging habitat. Joined‐up artificial supratidal management and natural intertidal habitat conservation are clearly required at our study site given the simultaneous dependence by over 35,000 migrating shorebirds on both habitats. Guided by observed patterns of habitat use, there is a clear opportunity to improve habitat condition by working with local land custodians to consider shorebird habitat requirements when managing supratidal ponds. This approach is likely applicable to shorebird sites throughout the EAAF.     

Sediment-benthos relationships as a tool to assist in conservation practices in a coastal lagoon subjected to sediment change

This study explores the relation between sediment composition and intertidal macrobenthos populations in the Zwin nature reserve (Belgium and The Netherlands), a tidal lagoon that is included in the Ramsar list of wetlands of international importance and has been designated as Natura 2000 area, among others due to its function as wintering habitat for shorebirds that feed upon macrobenthic invertebrates. Species response models show highest biomass of these prey species in organically enriched cohesive sediments and a distinct decline in probability of occurrence for most species in coarse sediments. Further, the biomass of macrobenthos declined between 2003 and 2010 in the extensive low intertidal inlet channel concurrent with the coarsening of the sediment over time in this hydrodynamically stressed habitat. In contrast, macrobenthos biomass increased in a sheltered shallow intertidal habitat that acted as a catchment area for finer sediments, therefore facilitating the succession towards a higher elevated habitat with salt marsh vegetation establishment. Hence, spatio-temporal sediment dynamics decreased site quality for intertidal predators due to a reduction in feeding areas over time, and a change in physical sediment properties that alter the macrobenthos species occurrence and population biomass. This study thus illustrates that sediment transport dynamics may affect the functioning of coastal shallow soft-sediment habitats, like coastal lagoons. The presented macrobenthos species response models provide a tool to assist in management actions that enable the conservation of cohesive low intertidal habitats that provide a high food supply to shorebirds, fish and macrocrustaceans.     

Recruitment of shore crabsCarcinus maenas on tidal flats: Mussel clumps as an important refuge for juveniles

During the late summer and early fall, juvenile shore crabs (Carcinus maenas L.) occurred in high abundances in mussel clumps scattered on tidal flats of the Wadden Sea. Abundances were much lower on bare tidal flats without mussel clumps and decreased substantially from July to November, whereas numbers in mussel clumps remained high. Large crabs left the tidal flats in early fall, whereas juveniles undertook tidal migrations only in the late fall. In March very few shore crabs were found in the intertidal area. The size of juvenile shore crabs living between mussels did not increase significantly during fall. On the bare tidal flats surrounding the mussels, a size increase was observed. Mussel beds and mussel clumps serve as a spatial refuge for the early benthic phases of juvenile shore crabs. Between mussels they can hide effectively from their epibenthic predators. Juvenile shore crabs do not leave the intertidal area and the mussel habitats before their major predators have left the area. Mussel clumps scattered over the tidal flats may be a critical refuge for juvenile shore crabs settling on tidal flats. Intensified efforts in mussel culturing in the European Wadden Sea during recent decades may have caused an increased abundance of mussel clumps on tidal flats, thus enhancing habitat availability for some mussel-clump inhabitants.     

Ecological contrasts across an Antarctic land–sea interface

Abstract We report the composition of terrestrial, intertidal and shallow sublittoral faunal communities at sites around Rothera Research Station, Adelaide Island, Antarctic Peninsula. We examined primary hypotheses that the marine environment will have considerably higher species richness, biomass and abundance than the terrestrial, and that both will be greater than that found in the intertidal. We also compared ages and sizes of individuals of selected marine taxa between intertidal and subtidal zones to test the hypothesis that animals in a more stressed environment (intertidal) would be smaller and shorter lived. Species richness of intertidal and subtidal communities was found to be similar, with considerable overlap in composition. However, terrestrial communities showed no overlap with the intertidal, differing from previous reports, particularly from further north on the Antarctic Peninsula and Scotia Arc. Faunal biomass was variable but highest in the sublittoral. While terrestrial communities were depauperate with low biomass they displayed the highest overall abundance, with a mean of over 3 × 10⁵ individuals per square metre. No significant differences in ages of intertidal and subtidal individuals of the same species were found, with bryozoan colonies of up to 4 years of age being present in the intertidal. In contrast with expectation and the limited existing literature we conclude that, while the Antarctic intertidal zone is clearly a suboptimal and highly stressful habitat, its faunal community can be well established and relatively diverse, and is not limited to short‐term opportunists or waifs and strays.     

Global patterns in the impact of marine herbivores on benthic primary producers

Despite the importance of consumers in structuring communities, and the widespread assumption that consumption is strongest at low latitudes, empirical tests for global scale patterns in the magnitude of consumer impacts are limited. In marine systems, the long tradition of experimentally excluding herbivores in their natural environments allows consumer impacts to be quantified on global scales using consistent methodology. We present a quantitative synthesis of 613 marine herbivore exclusion experiments to test the influence of consumer traits, producer traits and the environment on the strength of herbivore impacts on benthic producers. Across the globe, marine herbivores profoundly reduced producer abundance (by 68% on average), with strongest effects in rocky intertidal habitats and the weakest effects on habitats dominated by vascular plants. Unexpectedly, we found little or no influence of latitude or mean annual water temperature. Instead, herbivore impacts differed most consistently among producer taxonomic and morphological groups. Our results show that grazing impacts on plant abundance are better predicted by producer traits than by large-scale variation in habitat or mean temperature, and that there is a previously unrecognised degree of phylogenetic conservatism in producer susceptibility to consumption.     

Intertidal Benthic Invertebrates and Sediment Stability at the Mouth of Delaware Bay

From December 1970 to December 1972, the monthly species composition, density, species richness, and biomass of marine macroscopic invertebrates were quantitatively studied from a wave-protected, intertidal sand flat at the mouth of Delaware Bay. Considerable erosion, transportation, and deposition of sand occurred throughout the study period. The fauna was extremely flexible and resilient in its response to a gradient of considerable sediment mobility. This response was similar in scope to one recognized along the coast of California. Comparison of the local biota with other sand flats and beaches from Maine to South Carolina showed that (1). haustoriids were among the dominant species, (2). densities were roughly comparable, and (3). secondary species were similar. Based on the biological index value, three species contained 87.8% of the fauna from the Cape Henlopen tide flat. These species were the polychaete Scoloplos fragilis and the amphipod Neohaustorius biarticulatus, which were characteristic of sand bars, and the polychaete Heteromastus filiformis, which was more characteristic of troughs or depressions. Mean density varied considerably both monthly and annually with almost no cyclic repetition for any of the three species. There was evidence to indicate that specific habitat requirements of a few species can strongly affect the structure which emerges for a total fauna. Morphology, behavior, physiology, and reproductive strategy are aspects of biology which link dominant benthic species of intertidal sand beaches together.     

The relationship between invertebrate assemblages and bio-dependant properties of sediment in urbanized temperate mangrove forests

Relationships between ecological structure, functions and properties of sediments in intertidal mangrove forests and mudflats are poorly understood. Studies have not yielded consistent results, due to complex interactions between biotic and abiotic components. The benthic macrofauna in mangrove forests are important contributors to ecological functions, mediating various sedimentary properties. They vary in abundance and diversity at scales from centimeters to hundreds of metres in what appears to be similar “habitat”, but properties of sediments are often not measured at such small scales, or small-scale variation is ignored as random noise. Yet, there should be relationships between scales of variation in macrofauna and bio-dependant properties of sediments.This paper describes variation in assemblages of benthic invertebrates and bio-dependant properties of sediments at a hierarchical range of spatial scales, within and among different habitats in an urbanized mangrove forest and the associated intertidal mudflats in Sydney Harbour, Australia. Measurements were made on two occasions, in replicate sites in each habitat. These were used to test hypotheses about relationships of scales of variation in the benthos and sediments. The benthos showed relatively little difference in diversity and abundances among habitats compared to variation within and between sites in each habitat. The bio-dependant properties of the sediment showed less variation at small scales and larger among-habitat variation than did the benthos. Variation in the benthos did not clearly correlate with variation in the selected bio-dependant properties of the sediments at any scales. Neither did the properties of the sediment show consistent correlations in any habitat.These data indicate that the properties and processes driving the benthos are not simply related to the properties of the sediment we measured and that there was very large variation in both benthos and bio-dependant properties within small sites. This highlights the necessity of using experimental designs that sample at a hierarchy of scales for benthic assemblages and bio-dependant properties of sediment.     

泉州湾蟳埔潮间带大型底栖动物群落的时空分布

为了比较泉州湾蟳埔潮间带沙滩、互花米草滩和牡蛎石泥滩3种生境(3个潮层)的大型底栖动物群落,2011年4月至2012年1月对3种生境的大型底栖动物进行了季度定量取样。在3种生境共获得85种大型底栖动物,其中环节动物39种,软体动物20种,节肢动物21种,刺胞动物、扁形动物、纽虫动物、星虫动物和脊索动物各1种。多维标度排序(MDS)分析表明,春季和冬季泉州湾蟳埔潮间带3种生境的大型底栖动物群落相似性较低;夏季和秋季互花米草滩与牡蛎石泥滩的大型底栖动物群落相似性较高,而与沙滩的大型底栖动物群落相似性较低。沙滩大型底栖动物群落的季节变化较明显,其次是牡蛎石泥滩,而互花米草滩大型底栖动物群落的季节变化较不明显。大型底栖动物栖息密度和生物量随着潮层降低而增加。单变量双因素方差分析(Two-way ANOVA)表明,不同生境之间的大型底栖动物物种数、栖息密度、多样性指数、均匀度指数和丰度指数有显著差异,但生物量无显著差异,这是因为沙滩的物种数较少,栖息密度较低,但优势种弧边招潮蟹(Uca arcuata)个体较大,互花米草滩和牡蛎石泥滩的优势种为加州中蚓虫(Mediomastus californiensis),个体相对弧边招潮蟹小。不同季节之间大型底栖动物物种数、栖息密度、生物量和丰度指数有显著差异,但多样性指数和均匀度指数元显著差异,这是因为沙滩物种数少,但个体分布比较均匀,而互花米草滩和牡蛎石泥滩物种数较多,个体分布较不均匀。以上结果表明,潮汐、沉积物粒径和生境是影响潮间带大型底栖动物群落的主要因素。潮汐导致潮间带的空间异质性,空间异质性导致大型底栖动物群落的差异。     

Conservation and restoration of New Zealand Island ecosystems

An ecological collapse has precipitated pioneering conservation initiatives in New Zealand. Many terrestrial communities in t he New Zealand archipelago have been devastated by over-exploitation, introduced mammals and habitat destruction. More recently, marine ecosystems have been depleted by over-harvesting. To mitigate against these losses, conservation in terrestrial environments has focused on protection of species and habitats. A similar approach is now under way in marine environments with the establishment of ‘no-take’ marine reserves. On land, conservation is now reaching beyond protection t o the eradication of pests from islands and restoration of their terrestrial ecosystems. Restoration on islands not only reduces threats to rare species; it also raises opportunities to investigate how species interact. In the sea, marine reserves not only enhance the diversity of depleted marine communities; they may also augment stocks of commercially harvested species. These initiatives provide many lessons that could be applied to degraded habitats elsewhere.     

Application of CART in ecological landscape mapping: Two case studies

The goal of this paper is to introduce a statistical concept to derive ecological classifications of terrestrial and marine environments. Such ecological regionalisations reflect spatial combinations of biotic and abiotic characteristics and therefore may serve for environmental planning and monitoring issues. Referring to two case studies the paper presents how to calculate and map ecological defined regions from geodata by use of decision tree models and GIS-techniques. The first study deals with marine environments, exemplified by benthic habitats in the North Sea. The second study is on an ecological land classification of Europe which was computed using surface data on potential natural vegetation, elevation, soil texture and several climatic elements. Both the marine and the terrestrial ecoregions maps were combined with exposure data provided by environmental monitoring activities. The ecological land classification of Europe was intersected with measurement data on the metal loads in mosses taken from the German part of UN ECE moss surveys. In this way, the temporal development of the metal bioaccumulation within ecoregions since 1990 was assessed. The benthic habitat map was used to regionalise the temporal trend of the temperature conditions near the sea floor for the months of July and January from 1995 to 2000 by analysing these measurements according to the spatial categories of the habitat map. In the future, both ecological regionalisations should be used as a spatial framework for the analysis of up-to-date meteorological and phenological data in order to disclose climate change induced impacts.