272 CHAPTER 11 Sustaining Aquatic Biodiversity
deteriorating ecosystem services threaten people
and many other forms of life.- Protect and restore the world’s lakes and river sys-
tems, which are the most threatened ecosystems of
all. - Carry out ecological restoration projects worldwide
to heal some of the damage we have done and to
increase the share of the earth’s land and water al-
lotted to the rest of nature. - Find ways to make conservation financially re-
warding for people who live in or near terrestrial
and aquatic reserves so they can become partners
in the protection and sustainable use of the re-
serves.
There is growing evidence that the current harmful
effects of human activities on the earth’s terrestrial and
aquatic biodiversity and ecosystem services could be re-
versed over the next 2 decades. Doing this will require
implementing an ecosystem approach to protecting and
sustaining terrestrial and aquatic ecosystems. Accord-
ing to biologist Edward O. Wilson, such a conserva-
tion strategy would cost about $30 billion per year—an
amount that could be provided by a tax of one penny
per cup of coffee consumed in the world each year.
This strategy for protecting the earth’s precious bio-
diversity will not be implemented without bottom-up
political pressure on elected officials from individual
citizens and groups. People will also have to vote with
their wallets by not buying products and services that
destroy or degrade biodiversity. Finally, implementing
this strategy will require concerted efforts and coop-
eration among scientists, engineers, and key people in
government and the private sector.Lake Victoria and Sustainability
This chapter began with a look at how human activities have up-
set the ecological processes of Africa’s Lake Victoria (Core Case
Study).
Lake Victoria and other cases examined in this chapter illus-
trate the significant human impacts that have contributed to habi-
tat loss, the spread of invasive species, pollution, climate change,
and depletion of commercially valuable fish populations, as well
as degradation of aquatic biodiversity in general. We have seen
that these threats are growing and are even greater than threats
to terrestrial biodiversity.We also explored ways to manage the world’s oceans, fisher-
ies, wetlands, lakes, and rivers more sustainably by applying the
fourscientific principles of sustainability. This means reduc-
ing inputs of sediments and excess nutrients, which cloud water,
lessen the input of solar energy, and upset the natural cycling of
nutrients in aquatic systems. It means placing a high priority on
preserving the biodiversity and ecological functioning of aquatic
systems and on maintaining natural species interactions that help
to prevent excessive population growth of any one species, as
happened in Lake Victoria.REVISITING
By treating the oceans with more respect
and by using them more wisely,
we can obtain more from these life-supporting waters
while also maintaining healthy
and diverse marine ecosystems.
BRIAN HALWEILREVIEW
- Review the Key Questions and Concepts for this chap-
ter on p. 250. Describe how human activities have
upset ecological processes in East Africa’s Lake Victoria
(Core Case Study). - What are three general patterns of marine biodi-
versity? Why is marine biodiversity higher (a) near coasts
than in the open sea and (b) on the ocean’s bottom than
at its surface? Describe the threat to marine biodiversity
from bottom trawling. Give two examples of threats to
aquatic systems from invasive species. Describe the eco-
logical experiment involving carp removal in Wisconsin’s
Lake Wingra. How does climate change threaten aquatic
biodiversity?- What is a fishprint? Describe the collapse of the cod fish-
ery in the northwest Atlantic and some of its side effects.
Describe the effects of trawler fishing, purse-seine fishing,
longlining, and drift-net fishing. - How have laws and treaties been used to help sustain
aquatic species? Describe international efforts to protect