Mesopelagic-boundary community in Hawaii: Micronekton at the interface between neritic and oceanic ecosystems

The present study demonstrates that a distinct land-associated community of mesopelagic micronekton exists around the Hawaiian Islands. This mesopelagic-boundary community replaces the oceanic mesopelagic community over bottom depths of approx 400 to 700 m and includes about 14 species of fishes, 5 of shrimps and 4 of squids. Similar species of the mesopelagic micronekton have been reported in association with other landmasses at the boundary between the oceanic mesopelagic realm and upper continental or island slopes. These species may form a cosmopolitan mesopelagic-boundary community which shows regional differences in taxonomic composition, abundance and diversity. Boundary communities, with populations which are both tightly constrained geographically and relatively accessible to shore-based research programs, offer unique opportunities for studying biological processes of the mesopelagic realm and the interactions between neritic and oceanic populations. Data is presented from three midwater and two neuston sampling projects undertaken around the main Hawaiian Islands between 1987 and 1989; additional evidence from the literature is also discussed.     

Energy gains predict the distribution of plains bison across populations and ecosystems

Developing tools that help predict animal distribution in the face of environmental change is central to understanding ecosystem function, but it remains a significant ecological challenge. We tested whether a single foraging currency could explain bison (Bison bison) distribution in dissimilar environments: a largely forested environment in Prince Albert National Park (Saskatchewan, Canada) and a prairie environment in Grasslands National Park (Saskatchewan, Canada). We blended extensive behavioral observations, relocations of radio-collared bison, vegetation surveys, and laboratory analyses to spatially link bison distribution in the two parks and expected gains for different nutritional currencies. In Prince Albert National Park, bison were more closely associated with the distribution of plants that maximized their instantaneous energy intake rate (IDE) than their daily intake of digestible energy. This result reflected both bison's intensity of use of individual meadows and their selection of foraging sites within meadows. On this basis, we tested whether IDE could explain the spatial dynamics of bison reintroduced to Grasslands National Park. As predicted, bison distribution in this park best matched spatial patterns of plants offering rapid IDE rather than rapid sodium intake, phosphorus intake, or daily intake of digestible energy. Because the two study areas have very different plant communities, a phenomenological model of resource selection developed in one area could not be used to predict animal distribution in the other. We were able, however, to successfully infer the distribution of bison from their foraging objective. This consistency in foraging currency across ecosystems and populations provides a strong basis for forecasting animal distributions in novel and dynamic environments.     

Biological benthic tools as indicators of coastal marine ecosystems health

Coastal marine ecosystems are increasingly subjected to environmental stress and degradation due to pollution. Several research programmes have addressed this problem and produced relevant data sets for specific areas, often including consistent sets of environmental and biological variables. The value of existing information gathered from these types of data can be largely increased by combining them into a common data set to determine globally applicable relationships. To perform this exercise, the Intergovernmental Oceanographic Commission (IOC) of UNESCO has recently formed the Ad hoc Study Group on Benthic Indicators (http://www.ioc.unesco.org/benthicindicators) with the aim of developing robust indicators of benthic health. In this paper, initial products and ongoing activities of this international initiative are described and discussed. An expansion of initial IOC/UNESCO research on benthic fauna-organic carbon relationships is also presented. As part of this follow-up research, the relationship between total organic carbon concentrations of sediment and abundance, biomass and species diversity of benthic macrofauna was evaluated using data sets from 2 different regions of the world comprising 3 different coastal marine environments. The ability of identifying threshold levels in selected variables that could serve as indicators of related adverse environmental conditions leading to stress in the benthos is envisaged within the frame of a larger joint analysis, carried out by the IOC/UNESCO Study Group on Benthic Indicators, of merged data sets from several coastal regions worldwide.     

Ecosystem services as a counterpart of emergy flows to ecosystems

A generic input-state-output scheme has been used to represent ecosystem dynamics. Systemic approaches to ecosystems use functions that are based either on inputs, state or outputs of the system. Some examples of approaches that use a combination of functions have been recently proposed. For example the use of eco-exergy to emergy flow can be seen as a mixed input-state approach; more recently, to connect the state to the output of the ecosystem, the relation of eco-exergy and ecosystems services has been proposed. This paper studies the link between the useful output of an ecosystems and its input through the relation between ecosystem services and emergy flow, in a kind of grey/black box scheme (i.e., without considering the state and the structure of the ecosystem). No direct connection between the two concepts can be determined, but identifying and quantifying the emergy flows feeding an ecosystem and the services to humans coming from them facilitate the sustainable conservation of Nature and its functions. Furthermore, this input-output relation can be established in general by calculating the ratio of the value of the ecosystem services to the emergy flow that supports the system. In particular, the ratio of the world ecosystem services to the emergy flow supporting the entire biosphere has been calculated showing that, at least at the global level, Nature is more efficacious in producing “money” (in form of ecosystem services) than economic systems (e.g., national economies and their GDP).     

Application of CO2-porometer methods to assessment of components of photosynthetic production in estuarine ecosystems

A portable system for CO₂ gas exchange measurements is described that allows determination of net photosynthesis and transpiration rates as well as leaf conductance of salt marsh vascular plants, and photosynthesis rates of macrophytic algae and epibenthic algae of sediment cores during low tide periods of exposure. Carbon fixation processes of these several different types of organisms can be studied on the same day. Measurements may be carried out at an estuarine field site using controlled conditions of light, temperature, and air CO₂ partial pressure. Algal samples are enclosed in the cuvette for only a matter of minutes and do not dry significantly during measurement. The rapidity with which gas exchange rates of samples may be assessed will allow routine processing of many sediment cores. Thus, the distribution of producer populations can be studied with greater resolution than previously possible.     

Changes in size and trends of North American sea duck populations associated with North Pacific oceanic regime shifts

Broad-scale multi-species declines in populations of North American sea ducks for unknown reasons is cause for management concern. Oceanic regime shifts have been associated with rapid changes in ecosystem structure of the North Pacific and Bering Sea. However, relatively little is known about potential effects of these changes in oceanic conditions on marine bird populations at broad scales. I examined changes in North American breeding populations of sea ducks from 1957 to 2011 in relation to potential oceanic regime shifts in the North Pacific in 1977, 1989, and 1998. There was strong support for population-level effects of regime shifts in 1977 and 1989, but little support for an effect of the 1998 shift. The continental-level effects of these regime shifts differed across species groups and time. Based on patterns of sea duck population dynamics associated with regime shifts, it is unclear if the mechanism of change relates to survival or reproduction. Results of this analysis support the hypothesis that population size and trends of North American sea ducks are strongly influenced by oceanic conditions. The perceived population declines appear to have halted >20 years ago, and populations have been relatively stable or increasing since that time. Given these results, we should reasonably expect dramatic changes in sea duck population status and trends with future oceanic regime shifts.     

Interpreting beta‐diversity components over time to conserve metacommunities in highly dynamic ecosystems

The concept of metacommunity (i.e., a set of local communities linked by dispersal) has gained great popularity among community ecologists. However, metacommunity research mostly addresses questions on spatial patterns of biodiversity at the regional scale, whereas conservation planning requires quantifying temporal variation in those metacommunities and the contributions that individual (local) sites make to regional dynamics. We propose that recent advances in diversity‐partitioning methods may allow for a better understanding of metacommunity dynamics and the identification of keystone sites. We used time series of the 2 components of beta diversity (richness and replacement) and the contributions of local sites to these components to examine which sites controlled source‐sink dynamics in a highly dynamic model system (an intermittent river). The relative importance of the richness and replacement components of beta diversity fluctuated over time, and sample aggregation led to underestimation of beta diversity by up to 35%. Our literature review revealed that research on intermittent rivers would benefit greatly from examination of beta‐diversity components over time. Adequately appraising spatiotemporal variability in community composition and identifying sites that are pivotal for maintaining biodiversity at the landscape scale are key needs for conservation prioritization and planning. Thus, our framework may be used to guide conservation actions in highly dynamic ecosystems when time‐series data describing biodiversity across sites connected by dispersal are available.     

Information indices as a tool for quantifying development of below-ground terrestrial ecosystems

Information indices from ecosystem network analysis (ENA) describe the size and organization of an ecosystem and are claimed to quantify ecosystem development [Ulanowicz, R.E., 1986, Growth and Development, Springler-Verslag, New York, 203 pp.]. To date, these indices were not used to describe a gradient of ecosystem development for a field situation. Here we used information indices to quantify soil succession with soils of different age on the island Schiermonnikoog, The Netherlands. We evaluated whether information indices describe ecosystem development as predicted by ENA.For the Island of Schiermonnikoog the biomasses of soil organisms and roots were measured on four stages of succession (0, 10, 25 and 100 years old soils). Organisms were grouped based on their feeding characteristics. With these data consumption, respiration, excretion, external input and output flows to, from and between groups were calculated. These flows, in turn, were used to calculate the information indices. Relative information indices describe the organization of an ecosystem; i.e. level of organisation (specialization of flows), diversity and evenness of flows, and disorganisation. Absolute indices describe both size (in terms of energy flow) and organisation of the system. System size is used to scale the absolute indices and will be analysed separately as well.We found that the absolute indices increased when succession processed, as predicted by theory. This pattern could have been due to the build-up of biomass, which apparently did not level off. Because the succession gradient deals mostly with young soils (0, 10 and 25 years old) and only one older field (100 years old), the gradient should include more soils of around 100 years old and older to exclude this possibility. Relative indices, on the other hand, increased initially, but then levelled off. We think that this was due to the strong aggregation of functional groups, especially at lower trophic levels, because information in some functional groups showed (expected) trends.Our results suggest that the absolute indices are able to describe ecological succession of terrestrial below-ground ecosystems. The relative indices, in contrast, appeared to be insensitive to subtle succesional changes.     

Biosynthesis of wax esters in oceanic crustaceans

Slices from the hepatopancreas of various oceanic curstaceans incorporated radioactivity into wax esters from ¹⁴C glucose and ¹⁴C aspartic acid to a lesser extent and from ¹⁴C palmitic acid to a much greater extent. Radioactivity was incorporated from ¹⁴C palmitic acid into both fatty acid and fatty alcohol moieties of wax esters, the percentage of total radioactivity present in alcohol moieties being greater in deep-living than in shallow-living species. Cell-free preparations from the hepatopancreas but not from muscle, supplemented with ATP and reduced pyridine nucleotides, incorporated radioactivity from 1-¹⁴C palmitoyl Coenzyme A into both fatty alcohol and fatty acid moieties of wax esters. Incorporation into fatty alcohol was NADPH- rather than NADH-specific. Preparations from deep-living species had a greater percentage of total radioactivity in the fatty alcohol moieties of wax esters than preparations from shallow-living species. We conclude that the level of wax esters in a given species is correlated with the rate at which the species biosynthesises these lipids de novo; deep-living species have higher rates of wax ester biosynthesis and higher levels of wax esters than shallow-living species. The results support the thesis that wax esters in oceanic crustaceans are derived largely from the animals' internal biosynthetic activities, presumably in response to particular biochemical and/or physiological requirements, rather than from their diets.     

A bio-inspired computing model as a new tool for modeling ecosystems: The avian scavengers as a case study

The models used for ecosystems modeling are generally based on differential equations. However, in recent years new computational models based on biological processes, or bioinspired models, have arisen, among which are P systems. These are inspired by the functions of cells and present important advantages with respect to traditional models, such as a high computational efficiency, modularity and their ability to work in parallel. They are simple, individual-based models that use biological parameters that can be obtained experimentally. In this work, we present the framework for a model based on P systems applied to the study of an ecosystem in which three avian scavengers (predators) interact with 10 wild and domestic ungulates (preys). The computation time for 100 repetitions, corresponding to 14 simulation years each, with an initial population composed of 385,422 individuals, was 30 min. Our results suggest that the model presented, based on P systems, correctly simulates the population dynamics in the period of time analyzed. We discuss the usefulness of this tool in simulating complex ecosystems dynamics to aid managers, conservationists and policy-makers in making appropriate decisions for the improvement of management and conservation programs.     

The influence of contrasting life history traits and oceanic processes on genetic structuring of rabbitfish populations Siganus argenteus and Siganus fuscescens along the eastern Philippine coasts

Genetic variability and structuring of rabbitfish populations with contrasting life histories, Siganus argenteus and Siganus fuscescens were determined using allozyme analysis. A total of 13–14 polymorphic loci were examined from samples collected in 2002 and 2003 from eight reefs representing 25 populations north (Kuroshio Current) and south (Mindanao Current) of the bifurcation of the North Equatorial Current along the eastern Philippine coast. S. fuscescens populations (H _OBS = 0.085) showed higher heterozygosity than S. argenteus (H _OBS = 0.053), consistent with predictions of the neutral theory for demersal egg spawners compared to pelagic egg spawners. The generally lower genetic variability of Kuroshio populations may be due to greater environmental disturbance affecting larval mortality and recruitment success. There was no significant overall population genetic structuring for S. argenteus (F _ST = 0.01485, P > 0.05) compared to S. fuscescens (F _ST = 0.03275, P < 0.05). The latter species showed highly significant genetic structuring among Kuroshio and Mindanao Current populations in both 2002 and 2003 (F _CT = 0.08120, P < 0.05; F _CT = 0.07500, P < 0.05, respectively), as well as among populations within regions. This conforms to expectations of correlations between observed population genetic structure and life history features related to dispersal potential and gene flow. However, there were significant temporal (i.e., 2002 vs. 2003 samples) genetic variations for both S. fuscescens (F _CT = 0.08542, P < 0.05) and S. argenteus (F _CT = 0.06330, P < 0.05), which may reflect interannual variability in recruitment success. Differences in population spatial genetic patterns between the two reef fish species suggest that broad scale physical factors (e.g. NEC bifurcation) and regional environmental perturbations (e.g. incidence of typhoons) affect population genetic structure of sympatric congeneric species with different life histories differently. Finer scale ecological processes, which affect larval dispersal and recruitment (e.g., local hydrographic features, distribution of habitats), particularly in the Mindanao Current region, exert more influence on structuring populations of S. fuscescens.     

Cybernetic formulation of control in ecosystems

Hierarchical control formulations are given for a simple predator-prey model: self-optimization of one subsystem, natural multi-goal optimization, man's multiparameter control of an ecosystem and man's control of a self-optimizing ecosystem. Natural multigoal optimization suggests how several levels of an ecosystem can be optimized simultaneously. The idea of management of a self-optimizing ecosystem takes into account the reactions of the ecosystem to man's activity.     

Studies on the lipid metabolism of some oceanic crustaceans

Mid-water, oceanic crustaceans were either fed food labelled with (¹⁴C) palmitic acid under controlled conditions, or injected directly with (¹⁴C) palmitic acid. Lipid classes and their constituent fatty acids and fatty alcohols were subsequently separated and assayed for radioactivity. Significant levels of radioactivity were present in the 16:0¹ alcohols and 18:1 acids of wax esters, and in the 16:0/16:1, 18:0/18:1, 20:5 and 22:6 acids of both triglycerides and phospholipids. It was concluded that these crustaceans were capable of biosynthesis of wax esters and higher polyunsaturated fatty acids.     

Modelling phytoclimatic versatility as a large scale indicator of adaptive capacity to climate change in forest ecosystems

CLIMPAIR is a new phytoclimatic model, correlative and niche-based, which simultaneously assesses non-linear, non-statistical and dual measurements of proximity/potentiality of a site with respect to a number of climatic ranges of species, defined by convex hulls, within a suitability space. This set of phytoclimatic distances makes it possible to evaluate the degree to which each species is suitable for that site. Considering not only the number of species compatible (expected species richness), but also all those compatible covers presenting a high level of suitability evenness and finally applying an indicator derived from Shannon's classic entropy index to the set of standardized phytoclimatic coordinates in the suitability hyperspace, we can evaluate the phytoclimatic entropy which may be considered as a means of estimating the phytoclimatic versatility of the site. A site with high phytoclimatic entropy would promise versatile future behaviour, characterized by a wide range of possibilities of adaptation to climate change, and hence versatility can be used as an index of resilience and ability of a forest ecosystem to adapt to climate change. The model has been applied to peninsular Spain for 18 forest tree species and 12 climatic variables between the current mean climate (period 1951-1999) and a future climatic scenario (period 2040-2069). The results generally point to a significant decrease in the versatility of forest tree formations in the area studied, which is not homogeneous owing to a dual altitudinal/latitudinal decoupling. The decrease in versatility is greater in Mediterranean biogeographical areas than in Euro-Siberian ones, where in some cases it actually increases. In altitudinal terms, areas at elevations of less than 1500 m tend to become less versatile than areas situated at higher elevations, where versatility increases partly as a result of enrichment of alpine conifer forests with broadleaf species.     

An instance of bacterial inhibition in oceanic surface water

Water from the 150 surface film 50 miles north of Puerto Rico at 19°30 N, 66°30W supported only a negligible microflora compared to that of adjacent stations. Bacteriostasis was indicated when a ten-fold dilution of the sample resulted in a ninety-fold increase in cultivable microorganisms. The surviving organisms, atypical pseudomonads, were biochemically inactive in comparison to isolates from the other stations. Net phytoplankters at this station were similar in relative composition and abundance to those at the adjacent station.     

The potential of marine live-bait introductions into oceanic islands

The likely introduction of non-indigenous species into the coastal ecosystems of oceanic islands through live-bait utilizations was studied. A store survey identified the species that are traded as live fishing-bait. Only Polychaeta species were identified as imported live-bait on São Miguel Island and all specimens were identified as Perinereis linea. Reponses to surveys of 77 anglers showed that: 44 % harvest from native sources, 44 % buy live-bait and 12 % do both; 56 % of the anglers’ fish on a weekly basis; 31 % dispose of the bait into the sea. A field survey at five sites where fishing rods are routinely utilized was developed to investigate if the non-indigenous polychaetes sold as fishing-bait are already established in the natural environment of the Azores archipelago. Three species of Nereididae were identified: the native Neanthes nubila and P. oliveirae and the cryptogenic P. cultrifera. The escalating utilization of live-bait argues for a change in the habits of fishermen with respect to the discarding of leftover bait, as the higher the volume of discards the higher becomes the probability of non-indigenous species establishment successes, especially on oceanic islands characterized by vulnerable ecosystems with simpler trophic webs.     

Bacterial symbionts as an additional cytological marker for identification of sponges without a skeleton

Symbiotic bacteria from six Oscarella species (adults and embryos) collected in the Mediterranean Sea (O. lobularis, O. tuberculata, O. imperialis, O. microlobata, O. viridis) and the Sea of Japan (O. malakhovi) were investigated by scanning electron microscopy and transmission electron microscopy. In most cases, symbionts are rather numerous. Each sponge species has a definite set of bacterial morphological types. All bacteria are extracellular. Symbionts occupy the mesohyl of adult sponges or intercellular space in embryos and are often in contact with mesohylar filaments or cells. Bacteria of some morphotypes have characteristic blebs. Most symbionts are gram-negative, and two types of bacteria have traits of Archaea and one type of bacteria is similar to Planctomycetes. Data on morphology of bacterial symbionts can be a good additional character for identification of Oscarella species, which have no skeleton.     

Scenarios of major terrestrial ecosystems in China

The spatial pattern and mean-center shift of major terrestrial ecosystems, termed Holdridge Life Zones (HLZ), during the periods from 1961 to 1990 (T1), from 2010 to 2039 (T2), from 2040 to 2069 (T3) and from 2070 to 2099 (T4) were analyzed by combining the zonal patterns of climatic change in China and the climatic change scenarios of HadCM2 and HadCM3. The results showed that nival area would decrease rapidly with temperature increase in the future. HadCM2 and HadCM3 predicted that the nival areas might disappear in 552 years and 204 years, respectively. Using both HadCM2 and HadCM3, the five HLZ types with the largest areal extent are nival zone, cool temperate moist forest, warm temperate moist forest, subtropical moist forest and boreal wet forest, which collectively account for more than 50% of China's land mass. Among these five HLZ types, nival zone, warm temperate moist forest and boreal wet forest would decrease continuously, whereas subtropical moist forest and cool temperate forest would increase continuously during the four periods. HLZ diversity and patch connectivity would increase continuously in the 21st century. The shift distances of mean centers of HLZ types simulated using HadCM3 were markedly greater than those simulated using HadCM2, in general. The results from both HadCM2 and HadCM3 showed that boreal wet forest, subtropical moist forest, tropical dry forest, warm temperate moist forest and subtropical wet forest had bigger shift ranges, indicating that these HLZ types are more sensitive to the climatic change scenarios of HadCM2 and HadCM3.