remembering they can leach into waterbodies. Selective methods include “spot-
spraying,” weed-wiping (wiping a systemic herbicide against tall, unwanted
vegetation without touching shorter desirable vegetation below it), and drilling
holes into cut tree stumps and pouring herbicide into them. Manufacturer’s
instructions and best practice should always be followed.
14.4.4Taking account of predicted climate change
Impending climate change will necessitate a number of changes in current con-
servation practises. Shifts in the distribution of species resulting from climate
change (e.g. Thomas and Lennon 1999; Harrison et al. 2001) will require habi-
tat management to increasingly cater for the requirements of newly colonizing
species, rather than just focusing on those already present. The ability of indi-
vidual species to exploit changes in climate will be largely dependent on their
ability to colonize new areas. Less mobile species will be unable to disperse from
habitats that become increasingly unsuitable for them (e.g. Warren et al. 2001).
Shifts in climatic ranges of species can perhaps to some extent be catered for by
extending semi-natural habitat to higher altitudes, so that less mobile species
have shorter distances to disperse to remain within their climatic ranges. A par-
ticularly insidious threat is the increased potential for mobile nonnative species
to outcompete native species in semi-natural habitats. Another factor to con-
sider is potential changes in hydrology of wetlands resulting from changes in
precipitation and evapotranspiration.
Sea-level rise resulting from climate change and, in some areas, possible
increased storm activity are already thought to be responsible for losses of coastal
and associated habitat low-lying coastal habitats, such as saltmarshes and brack-
ish and freshwater marshes inland of them. In most cases, similar habitats are
preventing from re-forming further inland because of “hard” sea defences, result-
ing in a net loss of coastal habitat (e.g. Harrison et al. 2001). Large-scale habitat
creation behind existing seawalls will be necessary to offset these losses.
14.5 Managing grasslands
14.5.1Introduction
Except in very arid areas, most grasslands require periodic vegetation removal to
prevent colonization by scrub and trees, and in the case of some very wet grass-
lands, succession to fen. This can be done by grazing, cutting, or burning. The
latter is likely to be applicable only on drier grasslands, particularly those for-
merly maintained by natural fires. The primary consideration when managing
grasslands for birds is how to create the desired sward conditions at particular
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