Landscape Correlates of Large Mammal Occupancy in Chitwan Annapurna Landscape, Nepal
Date
2022
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Faculty of Zoology
Abstract
Human activities and natural processes are causing landscape change and biodiversity
loss. Large mammals are among the most threatened animals by land use and land cover
change (LULCC). They are under the pressure of habitat loss and alternation, especially
in the areas outside the protected area system. Chitwan Annapurna Landscape (CHAL)
is a north-south linkage between Chitwan National Park and Annapurna Conservation
Area in central Nepal that provide a safe passage of forest corridor for wildlife. This
study attempted to: 1) characterize the spatio-temporal pattern of land use and land
cover change in central part of CHAL; 2) evaluate the relative abundance of large
mammals and their interaction with people; 3) examine the impacts of environmental
correlates on the occupancy of large mammals, and 4) identify the landscape level
connectivity for the large mammals.
The LULCC in the area was characterized by supervised classification of Landsat
images for 2000, 2010 and 2020. Relative abundance of large mammals in four different
blocks (A–D) of the study area was done by line-transect (n = 150, average length =
3.18 ± 0.11 km) survey. Interaction of human with large mammals were assessed
through the questionnaire survey among 600 respondents. The occupancy of the large
mammals was evaluated using the program PRESENCE. Potential distribution of the
large mammals and their environmental correlates were identified by species
distribution modelling using maximum entropy algorithm. Important landscape patches
in the study area were identified and least-cost path approach with circuit theory was
used to pinpoint the linkages among those patches. The Kernel density estimation
method was used to identify the hotspots for the connection of isolated population of
the mammals in the patches.
The LULCC results revealed that forest is dominant feature of the study area. Overall
forest increased by 360.52 km
2
and cropland, grassland and barren area decreased by
329.45 km
2
, 46.78 km
2
and 12.18 km
ix
2
respectively from 2000 to 2020. A total of 18
species of large mammals were enumerated from primary field data. Chital was the
most abundant species in lowland (block A) and northern red muntjac in mid-hills
(blocks B, C and D). Among the carnivores, tiger was recorded only from the lowlands
while leopards were reported throughout the landscape, and Himalayan black bear was
reported in blocks B, C and D. Land cover types, anthropogenic disturbances, and
coverage of invasive and alien plant species (IAPS) have been identified to affect the
abundance of large mammals. The human-large mammal conflict is a serious problem
in this landscape with an estimated annual loss of US$ 12.02 and 74.60 per household
from crop damage and livestock depredation, respectively. The highest estimated
occupancy (ψ = 0.944 ± 0.048) was found for leopard whereas the lowest occupancy
was for Himalayan goral (ψ = 0.038 ± 0.011). Species distribution model predicted
30.29% of the study area as suitable habitats for northern red muntjac, 6.45% for chital,
2.6% for sambar, 14.55% for wild pig, 15.55% for Himalayan goral, 34.88% for rhesus
macaque, 34.65% for langur, 5.79% for Himalayan black bear and 29.94% for leopard.
A total of 15 habitat patches were identified in the central part of CHAL on the basis of
suitable habitats of mammals. The study found a poor connectivity among the patches
for chital and sambar, a strong connectivity for muntjac, leopard, rhesus macaque and
langur in the lowland to mid-hill and a strong connectivity for Himalayan black bear
and Himalayan goral in mid-hills.
The heterogeneity and dynamics in the landscape pattern in CHAL mainly attributed
forest change due to migration of people from rural to urban and lowland areas.
Landscape conservation efforts in the CHAL should maintain the contiguity of forest
patches. This research provides the baseline information of large mammals in the
CHAL and how they are responding to changes in the landscape. It reveals the role of
fragmented landscape for supporting large mammal assemblages and conserving
biodiversity.
Description
Keywords
Mammal occupancy, Landscape resistance