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PubMedDate not supplied

A model for simulating the effects of changing climate on the functioning and structure of the boreal forest ecosystem: an approach based on object-oriented design.

We have developed a forest ecosystem model to assess the effects of climate change on the functioning and structure of boreal coniferous forests assuming that temperature and precipitation are the major variables of the niche occupied by a tree species. We specified weather patterns to a level representing the time constant of different physiological and ecological processes relevant to the survival, growth and death of trees. We thereby coupled the long-term dynamics of the forest ecosystem with climate through physiological mechanisms such as photosynthesis and respiration in terms of energy flow through the ecosystem. The hydrological and nutrient cycles couple the dynamics of the forest ecosystem with climate change through soil processes, which represent the thermal and hydraulic properties of the soil, and the decomposition of litter and humus with mineralization of nutrients. Simulations for southern Finland (62 degrees N) indicated that an increase in temperature of 5 degrees C over one hundred years could reduce soil water in Scots pine-dominated forest ecosystems. At the same time, the temperature increase could enhance photosynthesis up to 6-8% under current CO(2) concentrations (330 ppm) and up to 8-10% under elevated CO(2) concentrations (660 ppm). Because the elevated temperature and CO(2) concentration caused an increase in respiration (12-14% more than under the current climate), total stem production increased only up to 4% with a 5 degrees C increase in temperature and up to 6% when temperature and atmospheric CO(2) concentration were increased simultaneously. Because transpiration only increased up to 5% in response to elevated temperature and CO(2) concentration, the water use efficiency of Scots-pine dominated forest ecosystems increased up to 3%, particularly during the late rotation.

Journal Article↗

PubMed2004

Molecular fingerprinting of dairy microbial ecosystems by use of temporal temperature and denaturing gradient gel electrophoresis.

Numerous microorganisms, including bacteria, yeasts, and molds, constitute the complex ecosystem present in milk and fermented dairy products. Our aim was to describe the bacterial ecosystem of various cheeses that differ by production technology and therefore by their bacterial content. For this purpose, we developed a rapid, semisystematic approach based on genetic profiling by temporal temperature gradient electrophoresis (TTGE) for bacteria with low-G+C-content genomes and denaturing gradient gel electrophoresis (DGGE) for those with medium- and high-G+C-content genomes. Bacteria in the unknown ecosystems were assigned an identity by comparison with a comprehensive bacterial reference database of approximately 150 species that included useful dairy microorganisms (lactic acid bacteria), spoilage bacteria (e.g., Pseudomonas and Enterobacteriaceae), and pathogenic bacteria (e.g., Listeria monocytogenes and Staphylococcus aureus). Our analyses provide a high resolution of bacteria comprising the ecosystems of different commercial cheeses and identify species that could not be discerned by conventional methods; at least two species, belonging to the Halomonas and Pseudoalteromonas genera, are identified for the first time in a dairy ecosystem. Our analyses also reveal a surprising difference in ecosystems of the cheese surface versus those of the interior; the aerobic surface bacteria are generally G+C rich and represent diverse species, while the cheese interior comprises fewer species that are generally low in G+C content. TTGE and DGGE have proven here to be powerful methods to rapidly identify a broad range of bacterial species within dairy products.

Animals↗

PubMed2006

Match your innovation strategy to your innovation ecosystem.

High-definition televisions should, by now, be a huge success. Philips, Sony, and Thompson invested billions of dollars to develop TV sets with astonishing picture quality. From a technology perspective, they've succeeded: Console manufacturers have been ready for the mass market since the early 1990s. Yet the category has been an unmitigated failure, not because of deficiencies, but because critical complements such as studio production equipment were not developed or adopted in time. Under-performing complements have left console producers in the position of offering a Ferrari in a world without gasoline or highways--an admirable engineering feat, but not one that creates value for customers. The HDTV story exemplifies the promise and peril of innovation ecosystems--the collaborative arrangements through which firms combine their individual offers into a coherent, customer-facing solution. When they work, innovation ecosystems allow companies to create value that no one firm could have created alone. The benefits of these systems are real. But for many organizations the attempt at ecosystem innovation has been a costly failure. This is because, along with new opportunities, innovation ecosystems also present a new set of risks that can brutally derail a firm's best efforts. Innovation ecosystems are characterized by three fundamental types of risk: initiative risks--the familiar uncertainties of managing a project; interdependence risks--the uncertainties of coordinating with complementary innovators; and integration risks--the uncertainties presented by the adoption process across the value chain. Firms that assess ecosystem risks holistically and systematically will be able to establish more realistic expectations, develop a more refined set of environmental contingencies, and arrive at a more robust innovation strategy. Collectively, these actions will lead to more effective implementation and more profitable innovation.

Commerce↗

PubMed2026

Orchard netting impacts on biodiversity leading to cascading effects at the ecosystem level.

Agriculture must ensure food production without further compromising the ecosystem functions upon which it depends. Agricultural practices should therefore avoid harming farmland biodiversity, especially of taxa that supply the key ecosystem services (e.g. pollination, pest control and nutrient uptake) that ultimately support crop production. Orchards are among the largest permanent plantations worldwide and are increasingly characterised by the spread of plastic nets used to protect fruits/nuts from either abiotic (anti-hail, anti-rain, shade nets) or biotic (exclusion nets) hazards. Despite having received little attention to date, these nets may impact natural communities, acting both as physical barriers and as drivers of habitat changes to which biota must respond. Species-level responses to netting depend on the organism's ability to enter the netted environment and successfully exploit available resources. Net-mediated ecological filtering and plastic behavioural responses may alter species interactions, leading to cascading ecological impacts that may create species-poorer 'netted communities' with simplified ecological networks. Such changes may erode biological control potential, other ecosystem functions, and overall system stability. We conducted a systematic review on the effects of protection nets on biota, and reported novel empirical evidence on anti-hail nets' impacts on communities of orchard-dwelling birds, flower-visiting insects, and rodents. In total, we identified 48 studies from the literature, however this literature was strongly biased towards apple orchards, western countries, and pest taxa. Net deployment was highly effective in deterring target pest species, in some cases regardless of their original function, as even weather-protection nets limited pest populations. Side effects on non-target taxa were also often reported, such as decreases in pollinators and natural enemies, and/or increases in secondary pests or microbial diseases. However, most assessments largely disregarded non-pest taxa and the broader ecological consequences of netting. The few studies that addressed the effects of nets at the guild/community level, including our empirical study, confirmed that orchard netting resulted in species-poor assemblages, with possible ecosystem-level consequences. We propose that future assessments should pay more attention to the indirect effects of netting on non-target taxa, and on the supply of crop-supporting ecosystem services mediated by wild species occurring in agroecosystems. Due to the trade-offs between these services and net-mediated crop protection, integrated alternatives should be tested to improve the environmental sustainability of food production and biodiversity conservation in farmed landscapes.

Biodiversity↗

PubMed1997

Literature review and analysis of biological complexity in model stream ecosystems: influence of size and experimental design.

A meta-analysis of more than 150 model stream ecosystem studies employed in hazard assessment was conducted to assess the effect of model ecosystem size on biological complexity and experimental design. Test system length was highly correlated to duration of colonization and chemical exposure period; however, size was generally unrelated to taxa richness, diversity, abundance, or biomass for algal, protozoan, and invertebrate assemblages. Fish were usually caged and not free-roaming, even in the relatively large (> 10 m) systems. Experimental designs, especially in recent years, have been less concerned with pseudoreplication, resulting in studies emphasizing numerous treatments with few or no replicates. Test systems have evolved that emphasize flow through exposures, use of natural source waters, and regression-style experimental designs. These factors collectively reduce problems historically associated with pseudoreplication. Larger model ecosystems (> 6 m) are advantageous for increasing the ability to sample more intensively through time and space without imposing sampling artifacts. Fish (caged and free-roaming) are also more often used in larger systems. Several model ecosystem studies that were compared with natural field-based communities demonstrated a high degree of correspondence for biological complexity attributes. Well-designed model stream ecosystems have a high degree of biological complexity and reasonable levels of variability for ecologically relevant endpoints. The use of small application factors (approximately equal to 1) is applicable to ecotoxicological results from these studies for risk assessment.

Animals↗

PubMed2002

Public support for ecosystem restoration in the Hudson River Valley, USA.

We applied the Theory of Planned Behavior to help understand the relationships between environmental beliefs, support for ecosystem restoration actions, and willingness to pay (WTP) for restoration and protection goals in the Hudson River estuary, New York State, USA. We conducted a mail survey with 3,000 randomly-chosen local residents of the Hudson River estuary in the fall of 1999. As hypothesized, the broad ecosystem restoration goals of the Hudson River Estuary Action Plan were more strongly supported than the corresponding specific implementation actions. We found that beliefs and past behavior were better explanatory variables than sociodemographic characteristics for explaining people's support for ecosystem restoration actions and WTP for restoration and protection goals. Because ecosystem restoration goals appear to be more generally acceptable than specific restoration actions, proponents of restoration programs should not become complacent about the need for active public outreach and involvement even if initial restoration program discussions have been low in controversy. Efforts to assess and foster support for ecosystem restoration should be targeted toward audiences identified on the basis of beliefs and past behaviors rather than on sociodemographic characteristics.

Adult↗

PubMed2002

Factors affecting private forest landowner interest in ecosystem management: linking spatial and survey data.

Many factors influence forest landowner management decisions. This study examines landowner decisions regarding participation in ecosystem management activities, such as a landscape corridor cutting across their private lands. Landscape corridors are recognized worldwide as an important tool in biodiversity conservation. For ecosystem management activities to occur in areas dominated by a multitude of small private forest landholdings, landowner participation and cooperation is necessary. Data from a survey of landowners combined with an analysis of their land's spatial attributes is used to assess their interest in ecosystem management. Results suggest that spatial attributes are not good predictors of an owner's interest in ecosystem management. Other factors such as attitudes and opinions about the environment are more effective in explaining landowner interest. The results have implications for any land manager using GIS data and implementing ecosystem management activities on private forestland.

Conservation of Natural Resources↗

PubMed2005

Theory into practice: implementing ecosystem management objectives in the USDA Forest Service.

In the United States and around the world, scientists and practitioners have debated the definition and merits of ecosystem management as a new approach to natural resource management. While these debates continue, a growing number of organizations formally have adopted ecosystem management. However, adoption does not necessarily lead to successful implementation, and theories are not always put into practice. In this article, we examine how a leading natural resource agency, the United States Department of Agriculture Forest Service, has translated ecosystem management theory into concrete policy objectives and how successfully these objectives are perceived to be implemented throughout the national forest system. Through document analysis, interviews, and survey responses from 345 Forest Service managers (district rangers, forest supervisors, and regional foresters), we find that the agency has incorporated numerous ecosystem management components into its objectives. Agency managers perceive that the greatest attainment of such objectives is related to collaborative stewardship and integration of scientific information, areas in which the organization has considerable prior experience. The objectives perceived to be least attained are adaptive management and integration of social and economic information, areas requiring substantial new resources and a knowledge base not traditionally emphasized by natural resource managers. Overall, success in implementing ecosystem management objectives is linked to committed forest managers.

Conservation of Natural Resources↗

PubMed2003

Response of NDVI, biomass, and ecosystem gas exchange to long-term warming and fertilization in wet sedge tundra.

This study explores the relationship between the normalized difference vegetation index (NDVI), aboveground plant biomass, and ecosystem C fluxes including gross ecosystem production (GEP), ecosystem respiration (ER) and net ecosystem production. We measured NDVI across long-term experimental treatments in wet sedge tundra at the Toolik Lake LTER site, in northern Alaska. Over 13 years, N and P were applied in factorial experiments (N, P and N + P), air temperature was increased using greenhouses with and without N + P fertilizer, and light intensity (photosynthetically active photon flux density) was reduced by 50% using shade cloth. Within each treatment plot, NDVI, aboveground biomass and whole-system CO(2) flux measurements were made at the same sampling points during the peak-growing season of 2001. We found that across all treatments, NDVI is correlated with aboveground biomass ( r(2)=0.84), GEP ( r(2)=0.75) and ER ( r(2)=0.71), providing a basis for linking remotely sensed NDVI to aboveground biomass and ecosystem carbon flux.

Biomass↗

PubMed2006

Effects of an increase in summer precipitation on leaf, soil, and ecosystem fluxes of CO2 and H2O in a sotol grassland in Big Bend National Park, Texas.

Global climate models predict that in the next century precipitation in desert regions of the USA will increase, which is anticipated to affect biosphere/atmosphere exchanges of both CO(2) and H(2)O. In a sotol grassland ecosystem in the Chihuahuan Desert at Big Bend National Park, we measured the response of leaf-level fluxes of CO(2) and H(2)O 1 day before and up to 7 days after three supplemental precipitation pulses in the summer (June, July, and August 2004). In addition, the responses of leaf, soil, and ecosystem fluxes of CO(2) and H(2)O to these precipitation pulses were also evaluated in September, 1 month after the final seasonal supplemental watering event. We found that plant carbon fixation responded positively to supplemental precipitation throughout the summer. Both shrubs and grasses in watered plots had increased rates of photosynthesis following pulses in June and July. In September, only grasses in watered plots had higher rates of photosynthesis than plants in the control plots. Soil respiration decreased in supplementally watered plots at the end of the summer. Due to these increased rates of photosynthesis in grasses and decreased rates of daytime soil respiration, watered ecosystems were a sink for carbon in September, assimilating on average 31 mmol CO(2) m(-2) s(-1) ground area day(-1). As a result of a 25% increase in summer precipitation, watered plots fixed eightfold more CO(2) during a 24-h period than control plots. In June and July, there were greater rates of transpiration for both grasses and shrubs in the watered plots. In September, similar rates of transpiration and soil water evaporation led to no observed treatment differences in ecosystem evapotranspiration, even though grasses transpired significantly more than shrubs. In summary, greater amounts of summer precipitation may lead to short-term increased carbon uptake by this sotol grassland ecosystem.

Asparagaceae↗

PubMed2006

Collaborative science, policy development and program implementation in the transboundary Georgia Basin/Puget Sound ecosystem.

The transboundary Georgia Basin Puget Sound ecosystem is situated in the southwest corner of British Columbia and northwest comer of Washington State. While bountiful and beautiful, this international region is facing significant threats to its marine and freshwater resources, air quality, habitats and species. These environmental challenges are compounded by rapid population growth and attendant uiban sprawl. As ecosystem stresses amplified and partnerships formed around possible solutions, it became increasingly clear that the shared sustainability challenges in the Georgia Basin and Puget Sound required shared solutions. Federal, state and provincial institutional arrangements were made between jurisdictions, which formalized small scale interest in transboundary management of this ecosystem. Formal agreements, however, can only do so much to further management of an ecosystem that spans international boarders. A transboundary regional research meeting, the 2003 GB/PS Research Conference, opened the doors for large-scale informal cross-boarder cooperation and management. In addition to cooperation, continued efforts to stem toxic pollution, contain urban growth, and protect and restore ecosystems, require a commitment from scientists, educators and policy makers to better integrate research and science with decision-making.

Animals↗

PubMed2005

Kinetic characteristics of the theoretical ecosystems with different extent of openness.

In this paper, the influence of the extent of openness of ecosystem that is defined by the dilution rate, which characterizes the extent of flowage of the pond, on the intensity of the biotic circulation in ecosystems with different regulation types, number of trophic links and extent of closing has been investigated. We considered open systems, we took into account the return of the limiting substances, such as nitrogen and phosphorous, into the cycle by degradation of detritus and products of vital functions of consumers. It was shown by the numerical calculations that the increase of the dilution rate in without recycle ecosystems leads to increase of the net primary production up to the maximum value corresponding to the two-link trophic chain (biogenic substance and producer) and then, to gradually decrease. The residual concentration of biogenic limiting substances monotone increases. Net primary production and residual concentration of biogenic limiting substances in systems with recycle with even number of links behaves similarly to that in without recycle ecosystems. In the systems with recycle with the odd number of links that values lies on the stable level. We showed that in wide range of the dilution rate the recycling of the ecosystem can highly increase the net primary production and reduce residual concentration of biogenic limiting substances. The influence of the dilution rate on numbers of links that may exist in the system was analyzed.

Biodegradation, Environmental↗

PubMed2005

A rule-based approach to the modelling of bacterial ecosystems.

This paper presents an approach to ecological/evolutionary modelling that is inspired by natural bacterial ecosystems and bacterial evolution. An individual-based artificial ecosystem model is proposed, which is designed to explore the evolvability of adaptive behavioural strategies in artificial bacteria represented by rule-based learning classifier systems. The proposed ecosystem model consists of a n-dimensional environmental grid, which can contain different types of artificial resources in arbitrary arrangements. The resources provide the energy that is necessary for the organisms to sustain life, and can trigger different types of behaviour in the organisms, such as movement towards nutrients and away from toxic substances, growth, and the controlled release of signalling resources. The balance between energy and material is modelled carefully to ensure that the ecosystem is dissipative. Those organisms that are able to efficiently exploit the available resources gradually accumulate enough energy to reproduce (by binary fission) and generate copies of themselves in the environment. Organisms are also able to produce their own resources, which can potentially be used as markers to send signals to other organisms (a behaviour known as quorum sensing). The complex relationships between stimuli and actions in the organisms are stochastically altered by means of mutations, thus enabling the organisms to adapt to their environment and maximise their lifespan and reproductive success. In this paper, the proposed bacterial ecosystem model is defined formally and its structure is discussed in detail. This is followed by results from simulation experiments that illustrate the model's operation and how it can be used in evolutionary modelling/computing scenarios.

Bacteria↗

PubMed2005

The significance of agricultural vs. natural ecosystem pathways in temperate climates in assessments of long-term radiological impact.

Recent developments in performance assessment biosphere models have begun to emphasise the importance of natural accumulation pathways. In contrast to the agricultural pathways, the database for natural ecosystem pathways is less well developed, leading to a mismatch in quality of representations of the two types of system. At issue is the lack of reliable soil-plant and animal ingestion transfer factors for key radionuclides in natural ecosystems. The relative importance of the agricultural vs. natural ecosystem pathways is investigated here, in the context of a temperate site in present day, Eastern France. The BIOMASS Candidate Critical Group (CCG) methodology has been applied to map a set of eight candidate critical groups derived from the present-day societal context onto physical locations within a simple model of a river catchment system. The overall assessment model has been implemented using the Aquabios code. Annual individual dose to each of the CCGs has been calculated for each of the key radionuclides (79Se, 94Nb, 99Tc, 129I, 135Cs and 237Np) released to the valley aquifer and river. In addition to the traditional agricultural pathways, lifestyle groups exploiting natural habitats are explicitly addressed. Results show the susceptibility of different candidate critical groups to different radionuclides. A reference database typical of those employed in long-term performance assessment models is employed. Doses from external exposure (94Nb) and dust inhalation (237Np) are shown to dominate agricultural food consumption by factors of more than six, but, with the reference data set, foodstuffs obtained from natural ecosystems do not contribute significantly to critical group dose and, at most, show similar exposures to the agricultural pathways. This may lead to the conclusion that natural food can be ruled out of consideration in performance assessment models. However, systematic parametric sensitivity studies carried out on soil-plant and animal ingestion transfer factors restrict the validity of this observation and demonstrate the limitations of existing databases. Remaining uncertainties can be reduced by improving structural models for performance assessment and by better characterisation of sources of locally obtained foods. Improved characterisation of radionuclide accumulation in natural ecosystems in temperate as well as alternative future climate states should complement the modelling approach.

Agriculture↗

PubMed2004

Applications of C and N stable isotopes to ecological and environmental studies in seagrass ecosystems.

Stable isotopes of carbon and nitrogen are increasingly used in marine ecosystems, for ecological and environmental studies. Here, we examine some applications of stable isotopes as ecological integrators or tracers in seagrass ecosystem studies. We focus on both the use of natural isotope abundance as food web integrators or environmental tracers and on the use of stable isotopes as experimental tools. As ecosystem integrators, stable isotopes have helped to elucidate the general structure of trophic webs in temperate, Mediterranean and tropical seagrass ecosystems. As environmental tracers, stable isotopes have proven their utility in sewage impact measuring and mapping. However, to make such environmental studies more comprehensible, future works on understanding of basic reasons for variations of N and C stable isotopes in seagrasses should be encouraged. At least, as experimental tracers, stable isotopes allow the study of many aspects of N and C cycles at the scale of a plant or at the scale of the seagrass ecosystem.

Alismatales↗

PubMed2026

Spatially defined microenvironmental niches are associated with clinical outcome and tumor ecosystem diversity in head and neck cancer.

BACKGROUND: Head and neck squamous cell carcinoma (HNSCC) exhibits substantial biological heterogeneity that is not fully explained by human papillomavirus (HPV) status. The spatial organization of tumor, immune, and stromal cell populations and its relationship to clinical outcome remain incompletely understood. METHODS: We performed single-cell spatial transcriptomic and proteomic profiling of 44 primary HNSCC tumors, generating a spatial atlas of 19,471,501 cells across whole-slide tissue sections. Spatial niches and ecosystem states were identified through integrated computational analyses and evaluated for associations with tumor programs, clinicopathologic features, and patient outcomes. FINDINGS: HPV-negative tumors were enriched for fibroblast-rich, immune-poor niches associated with epithelial-mesenchymal transition and hypometabolic tumor programs, whereas HPV-positive tumors displayed more diverse immune, stromal, and vascular niche combinations and were enriched for immunogenic ecosystem states. Approximately 20% of HPV-positive tumors exhibited fibroblast-rich ecosystem architectures resembling HPV-negative disease and were associated with less favorable outcomes than other HPV-positive tumors of similar stage. In patient-derived co-culture models, extracellular matrix-associated fibroblasts were associated with epithelial-mesenchymal transition (EMT)-like tumor states, CD8+ T cell dysfunction, and chemotherapy resistance-associated phenotypes. CONCLUSIONS: Spatial ecosystem architecture is associated with clinically relevant heterogeneity beyond conventional HPV-based classification. Fibroblast-rich, immune-poor ecosystem states characterize a high-risk subset of HPV-positive tumors and may provide a framework for improved biological classification and risk stratification in HNSCC. FUNDING: This work was supported by the National Institutes of Health (R01CA291607 and R21CA267527-01) and the Feldstein Medical Foundation.

Humans↗

PubMed2006

Local facilitation, bistability and transitions in arid ecosystems.

Arid ecosystems are liable to undergo sudden discontinuous transitions from a vegetated to a desert state as a result of human pressure and climate change. A predictive framework about the conditions under which such transitions occur is lacking. Here, we derive and analyze a general model describing the spatial dynamics of vegetation in arid ecosystems considering local facilitation as an essential process. We investigate the conditions under which continuous or discontinuous transitions from a vegetated to a desert state are likely to occur. We focus on arid ecosystems but our approach is sufficiently general to be applied to other ecosystems with severe environmental conditions. The model exhibits bistability and vegetation patchiness. High local facilitation decreases the risk of discontinuous transitions. Moreover, for arid ecosystems where local facilitation is a driving process, vegetation patchiness indicates proximity to a transition point, but does not allow distinguishing between continuous and discontinuous transitions.

Desert Climate↗

PubMedDate not supplied

Assessing marine ecosystem response to nutrient inputs.

The response of the Pagasitikos Gulf to enrichment caused by run-off fertilizers and the development and evolution of harmful algal blooms is investigated through ecosystem modelling. A standard generic complex model has been developed to describe the ecosystem processes of Pagasitikos and has been validated with in situ data. Additionally external nutrient fluxes have been assimilated and incorporated into the ecosystem dynamics. The investigation of spatial effects due to nutrient enrichment is investigated along a North-South transect. When externally forced the model successfully assimilates the external river inputs producing nutrient and chlorophyll-a concentrations, which are in good agreement with the in situ data. The nutrient inputs result in a more stable ecosystem at the north part of the Gulf and in the development of eutrophic conditions. The changes in the ecosystem functioning with emphasis on the nutrient cycling, the increase of primary production, and the modes of operation are investigated and discussed.

Chlorophyll↗