Ecosystems processes 452

The changes in spatial distribution of mineral resources and the morphological and physiological characteristics of the dominant plants have an effect on key ecosystem processes by affecting the timing of growth and... 

Hunt, E. R. Jr., Piper, S. C., Nemani, R., Keeling, C. D., Otto, R. D. and Running, S. W. (1996). Global net carbon exchange and intra-annual atmospheric CO2 concentrations predicted by an ecosystem process model and three-dimensional atmospheric transport model. Global Biogeochem. Cycles 10, 431-456. 

G. A. Gilbert, C. P. Vance, and D. L. Allan. Regulation of white lupin root metabolism by phosphorus availability. Phosphorus in Plant Biology Regulatory Roles in Molecular. Cellular, Organismlc, and Ecosystem Processes (J. P. Lynch and J. Deikman. eds,), American Society of Plant Physiologists, 1998, p. 157. 

Biotic control over the functioning of soil ecosystems also follows the model described by Chapin et al. (1997) for universal ecosystem. Types of soil biota and their composition are likely to alter soil ecosystem processes through changes in the functional traits (Fig. 10.1). It can alter ecosystem processes, such as phosphorous transformation and availability by plants, which in turn modifies community... 

Fig. 10.1 Model representing components of soil ecosystem processes (Modified from Chapin et al. 1997). It depicts biotic control over the functioning of soil ecosystem. Biotic introductions, land use and atmospheric compositions influences species composition and diversity, which controls the biotic functional traits and ecosystem processes... 

Changes in species composition and diversity will affect the functioning of ecosystems most strongly when species differ in their effects on ecosystem processes or in their response to environmental changes. 

Nematodes play a major role in decomposition and nutrient cycling in soil food webs. Due to its important role in trophic interactions, they have received attention in farming systems especially in organic farming. Although nematodes represent a relatively small amount of biomass in soil, their presence across many trophic levels in soils is vitally important in soil environments and ecosystem processes (Ingham et al. 1986). 

Gottlieb OR (1990) Phytochemistry differentiation and function. Phytochemistry 29 1715-1724 Harbome AR, Mumby PJ, Micheli F, Perry CT, Dahlgren CP, Holmes KE, Brumbaugh DR (2006) The functional value of Caribbean coral reef, seagrass and mangrove habitats to ecosystem processes. Adv Mar Biol 50 57-189... 

Assessment end points directly influence the type, characteristics, and interpretation of data and information used for analysis and the scale and character of the assessment. For example, an assessment end point such as fecundity of bivalves defines local population characteristics and requires very different types of data and ecosystem characterization compared with aquatic community structure and function. When concerns are on a local scale, the assessment end points should not focus on landscape concerns. But if ecosystem processes and landscape patterns are being considered, survival of a single species would provide inadequate representation of this larger scale. 

Dame, R. F. 1993. The role of bivalve filter feeder material fluxes in estuarine ecosystems. In Bivalve Filter Feeders in Estuarine and Coastal Ecosystem Processes (R. F. Dame, Ed.), pp. 245-269. Springer-Verlag, New York. 

Allison, S. D. (2006b). Soil minerals and humic acids alter enzyme stability Implications for ecosystem processes. Biogeochemistry. 81, 361-373. 

Indirect effects can be substantially more far-reaching (in an ecosystem perspective) than direct chemical effects. Most herbicides used in the forest are not likely to directly affect many organisms in any ecosystem because few herbicides used in forestry are so inherently toxic or so widely distributed that the avoidance or detoxification mechanisms of all organisms would be overwhelmed. On the other hand, severe deleterious direct effects on only a few key organisms or ecosystem processes can have far-reaching (indirect) effects for many other components of the ecosystem. 

A key point is that all indirect effects are the result of a direct effect on some aspect of the system. This is extremely important in planning methods for assessing indirect effects. Because the direct effect can be evaluated by use of established dose response theory and by tests, many of the indirect effects can be evaluated by use of the existing ecosystem data bases and current studies of ecosystem processes without a large amount of specific testing (10). 

Chemically mediated interactions have important direct and indirect effects on communities from both ecological and evolutionary standpoints.22 341 Chemical defense or communication cannot be properly understood unless it is viewed through the lenses of population, community, and ecosystem processes, and this requires consideration of both the biotic and abiotic components of the natural environment.342 For example, chemically mediated foraging is affected by water flow because it relies on water-soluble cues that are carried away from prey.343 345 Similar constraints likewise modify the effectiveness of other waterborne cues, such as alarm signals, sexual pheromones, and settlement cues, in both mobile and sessile organisms.244 345 350... 

Deposition of regional pollutants subjects forests to different perturbations than local- pollutants because the doses are less. Rather than severe tree morbidity or mortality with dramatic symptoms, regional pollutants subtly change tree metabolism and ecosystem processes. Smith (14) provided a comprehensive review of subtle air pollution forest stress. 

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