Assessing relationship between mammal occurrence and forest vegetation structure by using GWR
Forests play the most important role in the ecosystem, providing shelter, food sources and territories to floras and faunas. Forests are degraded from time to time, and forest conversion to agricultural plantations, especially for oil palm cultivation, has led to the problem of deforestation. Lar...
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| Format: | Thesis |
| Language: | English |
| Published: |
2017
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| Online Access: | http://psasir.upm.edu.my/id/eprint/70896/1/FH%202017%207%20IR.pdf http://psasir.upm.edu.my/id/eprint/70896/ |
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| Summary: | Forests play the most important role in the ecosystem, providing shelter, food
sources and territories to floras and faunas. Forests are degraded from time to
time, and forest conversion to agricultural plantations, especially for oil palm
cultivation, has led to the problem of deforestation. Large-scale removal of trees
changes species composition and wildlife occupancy as wild animals are
sensitive to changes of landscapes. Preserving the primary forest is an excellent
way to sustain the species richness. This study was conducted to gain in-depth
insights into the existence of wildlife by assessing the numbers of species in two
forests with different vegetation structure conditions: i) disturbed forest, and ii)
undisturbed forest. A total of 120 camera traps were used to capture the images
of the numbers of wildlife in both forest areas, from May 2015 to March 2016. To
understand the driving factors that bring about wildlife existence within these two
forest conditions, habitat quality attributes were measured: i) trees with diameter
of above 45 cm at breast height (DBH) (DM45); ii) trees with DBH below 45 cm
(DL45); iii) number of bamboo clumps (BMBO); iv) number of liana species
(LANA); v) number of palm trees (PLMT); vi) number of fallen trees (FLTR); vii)
number of saplings (SPLG); and viii) number of seedlings (SDLG). Two types of
analyses have been conducted: i) general linear modelling; and ii) spatial
analysis by using Geographical Information System (GIS). The aims of analysis
with general linear modelling are to compare mammal species occurrence with
the number of images captured; and establish the relationships between
mammal species occurrence and the local factors in both the undisturbed and
disturbed forests. On the other hand, the purpose of GIS analysis is to determine
the explanatory variables that have non-stationarity effects on the mammal
species occurrence. From the images captured, 3,730 small to large-size
mammal species are identified. Of that, 15 of mammal species with small to large
size were taken for analyses. From the general linear model, the undisturbed
forest (n=2.683) has the highest mammal species occurrences compared with
that of the disturbed forest (n=1.383). The images captured in the undisturbed
forest are also high (n=50.87) compared with that of the disturbed forest (n=6.43). These comparative figures can be explained by the richness of
biodiversity in the native forest. The mammal species occurrences are influenced
by several factors; mammal species occurrence = f(number of lianas, trees with
DBH >45 cm, number of palm trees, number of bamboo clumps, number of
saplings). For GIS analysis, OLS Model 2 was examined and found to be the
best model to determine the mammal species occurrences, based on the lowest
AICc value of 210.81. The GWR Model 2 has been identified as the best method
to determine the influence on mammal species occurrence (R2=41.56%),
compared with GWR Model 1 (R2=32.87%), GWR Model 3 (R2=36.09%), OLS
Model 1 (R2=25.86%), OLS Model 2 (R2=24.90%) and OLS Model 3
(R2=14.96%). The findings of this study about wildlife species richness and
occupancy under different forest vegetation structures are indeed very valuable;
the wildlife department can utilise this information as guidance for the purpose
of conservation management and taking proactive measures. |
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