Pheasants: Status Survey and Conservation Action Plan ... - IUCN

During 2004, the contents of this Action Plan will be
reviewed and updated, and a third edition drafted to cover
the period 2005–09.
1.6 Threats to the survival of
pheasants
This section provides background information on the
major types of threat faced by pheasant species, gives an
overview of their importance, and illustrates their effects
with specific examples where possible.
Habitat loss and degradation
Habitat loss, in its many forms, is suspected of being a
contributing cause in the decline of most threatened
pheasant species. Areas of forested habitat may be
permanently or temporarily destroyed as a result of timber
harvesting, or through deforestation for other purposes
such as agricultural or urban encroachment, including
road building. Alternatively, habitats may effectively be
lost or rendered much less useful to wild species through
degradation resulting from an excess of activities such as
livestock foraging, or fodder and firewood collection.
Habitat destruction is characterised by complete
removal of the existing vegetation structure. For species
that are heavily dependent on forests, such as most
pheasants, the complete removal of all trees in an area
(deforestation) will inevitably cause a catastrophic decline.
Timber extraction by logging operations is the primary
reason for deforestation. Logging is especially common in
areas with tropical forest on level ground, where
commercially valuable trees can easily be extracted on a
large scale.
Logging operations are a major cause for concern in
the lowlands of Indonesia, especially when combined with
the expansion of human communities into the areas of
cleared forest (van Balen and Holmes 1993).
Approximately 1.3 million hectares of land were deforested
in Sumatra and Kalimantan between 1985 and 1997,
representing 26% of the total. A disproportionate amount
of this forest destruction has taken place in the level
lowlands and current predictions are that all such forest
will have been cleared by 2010 in these two places. Illegal
logging is rampant, even within national parks (D.A.
Holmes in litt.). It, therefore, seems certain that all the
pheasant species that routinely inhabit lowland tropical
rainforests in Sumatra and Borneo will be under serious
threat from habitat destruction. The species likely to be
the most adversely affected are the crested fireback, the
crestless fireback, and Bulwer’s pheasant.
On Hainan Island in China, destructive logging is
putting pressure on the two distinct pheasant subspecies
endemic to the island (silver pheasant Lophura nycthemera
whiteheadi and grey peacock-pheasant Polyplectron
bicalcaratum katsumatae). As a result of a ban on logging
primary forest in January 1994, however, habitat loss is
now less of a threat than it was previously (Gao Yu-ren
1998).
Forests may be cleared to make way for agricultural
uses, such as plantations of coffee, rubber, and tobacco, or
for the grazing of livestock. This is a particular problem
where intensive farming methods are used following habitat
clearance, as vast tracts of land may become permanently
inhospitable to many species of forest-dwelling animals.
For example, shifting cultivation in northeast India has
affected habitats of Blyth’s tragopan and grey peacockpheasant
(Kaul et al. 1995). The probable disappearance
of the green peafowl from lowland and riverine habitats in
this region may also be attributed to such practices (S.
Kumar in litt.).
Increasingly, forested habitats are being cleared to
make room for urban settlements, or for road building
and reservoir construction. For instance, near Darjeeling
in India, habitats for satyr tragopan and koklass have
been lost to urban expansion at Jorebunglow and Ghoom
(S. Khaling in litt.). The restricted range of the mountain
peacock-pheasant in Malaysia faces serious disruption if
a proposed road-building project to link the Genting
Highlands with Fraser’s Hill and Cameron Highlands is
allowed to proceed (Anon. 1998).
Whatever the reason for significant habitat destruction,
an almost inevitable result is the increased fragmentation
of any remaining habitat and, therefore, of the distribution
of species using it. Eventually, this can lead to the
disappearance of all but small blocks of suitable habitat,
which become separated from each other by large expanses
of uninhabitable ground. These habitat islands contain
populations that are often both small and isolated, making
them particularly vulnerable to extinction through the
combination of genetic, demographic, and environmental
effects generally referred to as the ‘extinction vortex’
(Primack 1998). The extinction of several such populations
over a short time may result in a major range contraction
and population decrease for the species as a whole.
Habitat degradation, as opposed to its destruction,
involves a reduction in quality without the loss of all the
original vegetation components or structure. It can occur
as a result of activities such as the selective removal of
minor forest products (e.g., medicinal herbs, fungi) or
foraging by domestic livestock. Selective logging, where
only a proportion of trees (usually valuable species) is
removed from the forest in a given area, may also be
detrimental. The term ‘selective logging’ is often taken to
imply that trees are harvested according to sustainable
principles and alterations to forest structure are as limited
as possible. At its most extreme, however, the remaining
forest is severely degraded and exhibits an unnaturally
5