Environmental Engineering Reference
In-Depth Information
Box 1.2 Ecological
tidbits
This topic, about how ecological theory can be harnessed to protect biodiversity and ecosystem
services, is divided into sections that relate to four areas of ecological theory (see chapter grouping
in the main contents list). Here are some morsels from the four chapter groupings to tempt your
appetite - one per chapter.
1 Ecological applications at the level of individual organisms
Niche theory and the translocation of New Zealand's takahe
Source: Ross Armstrong/Alamy.
One of the few remaining representatives of a guild of large, fl ightless birds, the takahe declined
almost to extinction because of human hunting and the effects of invaders that compete with them
(deer) or prey upon them (stoats). The surviving individuals were restricted to a remote and climati-
cally extreme mountain area. A conservation plan called for captive breeding and release of birds
in suitable habitat elsewhere. Selecting the correct release sites, a crucial step, depends on under-
standing the bird's niche requirements - but was their mountain distribution a refl ection of ideal
conditions or simply their last outpost? Managers used evidence of fossil remains to map the
takahe's historical distribution and throw light on its optimal niche requirements. Translocation of
individuals to lowland areas on offshore islands has proved successful (Section 2.3.2).
Species traits can predict invasive trees and threatened natives
Photo: M.P. Frankis.
Of a hundred pine species that have been introduced to the USA, a small proportion have caused
problems by spreading into native habitats. Their 'success' turns out to depend on certain traits,
including small seed size, a short interval between successive large seed crops and rapid maturity
to reproductive adult. Conversely, native pine species that are particularly prone to extinction, such
as Pinus maximartinezii , have precisely the opposite traits. Such patterns give managers something
to work on when it comes to predicting problematic invaders or identifying natives that are most
likely to need protection (Section 3.3.1).
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