The Giant Mole Rat, Tachyoryctes macrocephalus (Rüppell, 1942) As Ecosystem Engineer, in Sanetti plateau of Bale Mountains National Park, South Ethiopia.
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Date
2010-06
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Addis Ababa University
Abstract
Studies on Giant Mole Rats as ecosystem engineers were carried out on Sanetti
plateau, Bale Mountains National Park from July 2008 to March 2009 covering both wet and dry
seasons. Fifteen 50x50 m2 plots of which five with high giant mole rat density and five with low
giant mole rat and five with none-giant mole density were selected for the study on factors that
influence density and distributions on of giant mole rat and the impact on the environment. In
addition to this, ten 50x50 m2 plots of which five with high density giant mole at and five with
low density giant mole rat were selected for population and co-existence studies. An estimate of
48 maximum and 20 minimum individual giant mole rats were found per-hectare in the present
study. A total of 75 kg soil samples were taken from studied plots for soil carbon, nitrogen,
phosphorous and particle density study and 225 bags samples were taken for soil bulk density
test. The soil samples were tested for required parameters in Addis Ababa National Soil Test.
Soil properties, vegetation cover, livestock, grazing season, and slope were factors affect the
density and distribution of giant mole rats. The soil factors determine the number of mima
mound formation and number of fresh open and closed holes. The mean fresh open and closed
holes during dry and wet season were significantly different (t = -2.743, df = 9; P = 0.013 <
0.05; t = 4.300, df = 9, P = 0.00 < 0.05), respectively. Density and distribution of mole rats were
best indicated by the number of mime mound in a given area. The number of mima mound
showed statistically significant compared to fresh open and closed holes, old closed holes and
grazing intensity (P = 0.01 < 0.05). Giant mole rats aid soil formation, hence burrowing and
mima mound formation mix soil component. It also aerates and enriches soil with nutrients
whereas in other hand it enhances soil erosion by exposing soil to erosion factors. The
burrowing pattern of giant mole rats affect Soil carbon by releasing carbon dioxide into
atmosphere contributes to climate change. The soil carbon content and soil bulk density in giant
mol rat showed significantly different compared to none giant mole rat plots (F2, 72 = 19.1; P =
0.00 < 0.05; c2 = 5.699, df = 1; P = 0.017 > 0.005), respectively. Giant mole rat had mutual
way of living with the alpine chat and commensalisms with murid rodents The maximum
number of giant mole rat observed is statistically positively correlated with number of alpine
chat( = 0.05 ; r = 0.287) and total number of giant mole rats observed positively correlated
with total raptors( = 0.05; r = 0.303) in the studied plots. Combined effect of giant mole rat and
livestock would have caused great impact on the ecosystem. Conservation measure aimed at afro
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alpine ecosystem of Bale Mountains would take accounts the role of the giant mole rat as
ecosystem engineers.
Key words: Bale Mountains National Park, ecosystem engineer, giant mole rat, mima mound,
soil Carbon, soil bulk density.
Description
Keywords
Bale Mountains National Park, ecosystem engineer, giant mole rat, mima mound, soil Carbon, soil bulk density.