Environmental Engineering Reference
In-Depth Information
culture of science). In the midst of this conceptual revolution, frontiers include exploring
alternative ways to consider and interpret the role of humans in ecosystems. These new
modeling efforts will offer new frameworks and tools necessary to achieve more compre-
hensive views of environmental problems and help identify solutions.
Establishing New Links between Scales in Ecological Research
Scale and scaling issues have become a central issue in ecosystem science, and in
many ways, a unifying theme ( Levin 1992; Lovett et al. 2005 ). Although the word “scale”
has many definitions, in ecosystem science it most commonly refers to spatial or tempo-
ral grain size (the finest resolution possible in the data set), extent (size of the entire study
area or length of the study), or levels of organization (e.g., atoms
biological molecules
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organelles
cells
tissues
organs
organisms
populations
communities
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ecosphere; Schneider 2001 ). In the future,
scientists will increasingly find themselves attempting to connect ecological phenomena
across multiple scales, but substantial advances in theory are still needed to establish
and refine scaling frameworks in ecosystem science.
The concept of ecosystem heterogeneity is discussed in Chapter 10. Here, we focus on
some of the issues and challenges that are at the forefront of ecosystem science research
regarding scaling in space and time. First, ecosystem scientists are increasingly using
the knowledge gained from fine-scale studies to estimate or model processes at much
broader—even global—spatial scales. This aggregation of fine-scale data to estimate ecosys-
tem attributes at much broader spatial scales, while important to our understanding of
broad-scale or global processes, is fraught with error and uncertainties ( Rastetter et al. 1992;
Currie 2011 ). Recent and future technological advances in areas such as geographic informa-
tion systems and remote sensing (see the following section on sensors) will greatly aid in
estimating ecosystem attributes over large geographical areas ( e.g., Running et al. 2004 ).
Temporally, ecosystem scientists are also faced with integrating short-term data on the
structure and function of ecosystems with longer-term processes and trends. In global
climate change research, for example, knowledge gained from current short-term analyses
of climate-change drivers must be integrated with long-term climatic records and trends to
understand how the global climate has changed and will potentially change in the future.
Many ecological processes operate at multiple levels of organization. For example,
primary production by photoautotrophs can be estimated at the ecosystem level. However,
ecosystem-level primary production is the sum of primary production for all individual
photo-autotrophic organisms within the ecosystem. This is a result of photosynthesis in the
chloroplasts of individual organisms that ultimately determine the potential for primary
production in that ecosystem ( Allen et al. 2005 ). Therefore, primary production can be
studied from subcellular scales of biological organization to the entire ecosphere or Earth
( Field et al. 1995 ). While ecosystem scientists recognize that ecosystem processes operate at
multiple levels of organization, they lack a comprehensive framework that links processes
at the level of organization where they occur. Recently, the metabolic theory of ecology
( Brown et al. 2004 ), ecological stoichiometry ( Sterner and Elser 2002 ), or some combination
of these two frameworks has been proposed as a basis for assessing ecological processes
ecosystems
landscapes
biomes
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