Part III: Conservation and Management278
of seven Asian Sus species, and the three Babyrousa species, to be
Critically Endangered, Endangered or Vulnerable, with all spe-
cies facing high risks of near-future extinctions. The one excep-
tion to this status is Sus scrofa, the Eurasian wild boar, which
is expanding or recovering, and fairly stable within its range
(Meijaard et al. 2011; Massei et al. 2015; see also Chapter 21 in
this book). Underlying this appears to be an intriguing evolu-
tionary process. S. scrofa is a relative newcomer that started
to disperse across the Asian mainland during the Pleistocene,
when rapidly changing environmental conditions required
the sort of ecological versatility, rapid reproduction, and abil-
ity to switch between an r- and a K-strategy that characterizes
the species. Over the course of the Pleistocene, S. scrofa seems
to have replaced a range of species of the ‘warty-type’, such as
those now endemic to islands of South-East Asia. In fact, it
might well be that the competitively superior S. scrofa outcom-
peted warty-type pigs across Asia, or hybridized with them,
with only isolated island species being able to maintain viable
populations (Frantz et al. 2016). The pygmy hog (Porcula
salvania) is a possible example of this hypothetical pattern of
S. scrofa-driven displacement. Pygmy hogs now exclusively live
in a few tall grassland areas of Assam in the Himalayan foothills
of northern India (the ‘Terai’). No more than 250 adults sur-
vive in a few populations and the species is considered Critically
Endangered. They were thought to be ecologically specialized to
the conditions in these tall grasslands, but recent finds suggest
that up to the Late Pleistocene the genus Porcula survived in a
much larger area in South East Asia, including the island of Java,
Burma, and eastern China (Pickford 2013), indicating an ability
to use a variety of different vegetation types rather than tall sub-
Himalayan grasslands only. This raises the intriguing idea that
instead of limiting habitat conditions as a factor of pygmy hog
population decline, perhaps competition from S. scrofa was an
additional factor behind their decline.The final continent where the suids occur, Africa, pre-
sents a different conservation scenario. Overall, the five spe-
cies (although see Chapter 1 of this book, where Gongora et al.
suggest the three forest hog subspecies to be elevated to species
level, which would increase the total number to eight. However,
pending further investigation on Hylochoerus taxonomy, we will
still refer in this chapter to the three subspecies, acknowledging
that they might deserve a status of species) that occur there –
bushpig, red river hog, forest hog, and the two species of warthog
(Figure 26.2), remain relatively stable, although high predation
pressure and habitat loss and fragmentation are threats to these
species throughout much of the continent. All species are consid-
ered as Least Concern by the IUCN, although several subspecies
are under considerable conservation threats. For example, two of
the three subspecies of forest hog (Hylochoerus meinertzhageni
ivoriensis and H. m. meinertzhageni) experience strong popu-
lation fragmentation throughout their range due to forest loss
and hunting pressure. Red river hogs (Potamochoerus porcus)
also face great pressure from hunting in the Congo Basin and in
West Africa and some populations have seen a decrease of up to
79 per cent in recent years (Lahm 1990; Lameed et al. 2015; Leslie
& Huffman 2015), indicating that in some places this species is
threatened with extinction.Population Decline and Local Extinctions
Endangered peccary and pig species face similar threats such
as over-hunting and rapid rates of deforestation and habitat
loss (Table 26.1). These threats result in extensive population
declines and high likelihood of extinction, especially for geo-
graphically restricted species such as the Visayan warty pig,
which only occurs on some small Philippine islands, or the
Chacoan peccary, which is confined to one type of ecosystem.
The combination of habitat loss and fragmentation, and
over-hunting resulting in small population size and ultimatelyFigure 26.1 In 2012 deforestation in
the Gran Chaco totalled 540,000 ha,
an average of 1473 ha per day (photo
by Guyra Paraguay). (A black and white
version of this figure will appear in some
formats. For the colour version, please refer
to the plate section.).02812:52:18