Environmental Engineering Reference
In-Depth Information
theme. Indeed much of ecosystem science has been motivated by simple curiosity about
how our world and how systems—whether ecological, social, or socio-ecological—work.
Many salable products such as timber and fish are taken directly from “wild” ecosystems,
so many early ecosystem studies were done to try to better understand the processes that
supported these products and ultimately increase their yields. Especially in the past 20
years, we have come to realize that the valuable products of nature include far more than
obviously salable products like timber and fish. Wild ecosystems also provide us with
clean air and water, opportunities for recreation and spiritual fulfillment, protection from
diseases, and many more “ecosystem services” (e.g.,
Millennium Ecosystem Assessment
2005; Kareiva et al. 2011
). Human economies and well-being are wholly embedded in and
dependent on wild ecosystems. Thus, many contemporary ecosystem studies are con-
cerned with how ecosystems provide this broad array of services, how human activities
reduce or restore the ability of ecosystems to provide these services, and ultimately trying
to reconcile the growing demands of human populations with the needs of both nature
and ourselves for functioning ecosystems.
HOW DO ECOSYSTEM SCIENTISTS LEARN
ABOUT ECOSYSTEMS?
Depending on the problem that they are studying, ecosystem scientists use a wide vari-
ety of approaches and an array of simple to sophisticated tools to measure different
aspects of ecosystem structure and function. We offer a few examples here; however, new
approaches and tools emerge every year, and with them come more ways to open black
boxes in ecosystem science (see Chapter 17).
Approaches for Learning about Ecosystems
There are multiple approaches by which scientists can understand ecosystem structure,
function, and development, both qualitatively and quantitatively. Five approaches are
especially important in ecosystem science, including (1) natural history or observation,
(2) theory and conceptual models, (3) long-term study, (4) cross-ecosystem comparison,
and (5) experiments (modified from the lists of
Likens 1992; Carpenter 1998
). These
approaches are complementary to one another (
Table 1.1
), and are best used in combina-
tion. Almost every scientific question of any size or importance requires the use of two or
more of these approaches to get a satisfactory answer.
Natural History
A good deal can be learned about ecosystems simply from watching them and docu-
menting what is observed in some fashion. Do fallen leaves decay in place, wash away
into a stream, or burn in episodic fires? Is the soil deep and rich, or shallow and rocky?
Does it freeze in the winter? As a result, our understanding of an ecosystem often is based
on simple observations of its natural history. Indeed, without such careful observations,
even the most sophisticated studies can go astray by formulating nonsensical questions or
