Part III: Conservation and Management284
rates also relates to the ability of populations to compensate
losses through increased reproductive output. The latter, in
turn, depends highly on the biology of the species, the ecological
conditions in a particular area and the availability of resources.
Most species of pigs are able to increase their reproductive
output when ecological conditions are favourable. Bearded pigs,
S. barbatus, are a well-known example, with the species occur-
ring in a range of different population states depending on the
availability of fruit (Caldecott 1991). At times of low and dis-
persed food availability, the species occurs in small populations
of individual animals or small groups that feed on any available
foods that they can find. The other end of the social structure
extreme occurs after supra-annual mast fruiting when females
can have several litters within a short period, and large num-
bers of pigs gather in groups of hundreds or even thousands
of animals and migrate over long distances through Sumatran
and Bornean rainforests (Pfeffer 1959; Caldecott 1991; see also
Chapter 18 in this book). Unfortunately, recent observations of
bearded pig aggregations and group size in the last three years
have only been in the twenties (A. Granados, personal com-
munication). Interestingly, large movements have also been
reported for white-lipped peccaries occasionally aggregating
in particular sites such as water sources (Reyna-Hurtado et al.
2009) or mineral licks (Blake et al. 2011).
When logging, road development, and other anthropogenic
activities occur in peccary and pig habitat, these can reduce
the carrying capacity and cause local extinctions. Although
hunting was considered to be the major threat to the Chacoan
peccary, habitat destruction has recently become more impor-
tant. During the last 10 years, the pressures of land-use change
have definitively increased, particularly in the prime habitat in
Central Chaco (Guyra-Paraguay, personal communication;
Romero 2012). A study in the Argentine Chaco found that theChacoan peccary disappears when forest cover is reduced to less
than 87 per cent of the original cover (Altrichter & Boaglio 2004;
Figure 26.1). This has been demonstrated for white-lipped pecca-
ries that disappeared from well-preserved conservation units and
small forest fragments due to factors unrelated to hunting (Glanz
1990; Leigh & Wright 1990; Keuroghlian et al. 2013; Richard-
Hansen et al. 2014). For example, fruit productivity, habitat
diversity, water availability, and the extent of neighbouring habi-
tat usable by white-lipped peccaries may all be important to the
persistence of the species in forest fragments. These variables
may explain why certain populations have been able to survive
in fragments one-fifth the area of the large home ranges reported
from the Amazon, Pantanal, Cerrado, or from other forests in
Mesoamerica (Fragoso 1994; Carrillo et al. 2002; Reyna-Hurtado
et al. 2009; Jacomo et al. 2013; Keuroghlian et al. 2015).
Throughout their biogeographic range, the survival of white-
lipped peccaries in habitat fragments will also vary according to
the predominant vegetation type. The problems associated with
local extinctions of white-lipped peccaries in the Amazon region
are different from those which threaten this species in other
ecosystems that have become fragmented, such as the Atlantic
forest of southeastern Brazil. In the Amazon basin, the human
population is relatively sparse, and the region is still dominated
by undisturbed forest habitat. In this situation, recolonisation
of areas where local extinctions have occurred remains a pos-
sibility. In contrast, southeastern Brazil is densely populated,
and habitats have been extensively fragmented (Por 1992). In
most cases, recolonization of small, isolated fragments would be
impossible without human intervention, because source popu-
lations are not available in the vicinity to replace populations
that become locally extinct (Keuroghlian et al. 2004). Similar
isolation conditions occur with some of the pig species from
the Asian islands. For example, the Mindoro warty pigs areFigure 26.6 Young Mursi girls with
warthog headpieces in Omo Valley,
Ethiopia (photo by Kristan A. Norvig)..02812:52:18