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Authors
Info
B. Zodinpuii1, H.
Lalthanzara1*
and Lalnuntluanga2
1Department of
Zoology,
Pachhunga University
College, Mizoram University,
Aizawl-796 001,
Mizoram
2Department of
Environmental
Science, Mizoram University,
Tanhril-796 004, Mizoram
*Corresponding
Author Email :
hzara.puc@gmail.com
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Abstract
Aim: To investigate the
earthworm community and its interaction with traditional shifting cultivation
to find the effect of traditional shifting cultivation on diversity, density
and distribution of earthworms.
Methodology: Earthworm was
sampled from five random sites located at least 20 m apart at monthly
intervals by digging and hand sorting method during January 2013 to October
2015 in an experimental plot of one acre of natural forest, demarcated into
natural forest (control, CTRL) and traditional shifting (slash and burn)
cultivation site (Experimental, EXPTL) at Khawrihnim, Mizoram, North-east
India.
Results: A total of 11
species of earthworms belonging to five genera under three families were
recorded. Family Megascolecidae dominates with five species (Perionyx
excavatus, P. macintoshi, Metaphire houlleti, Amynthas alexandri and A.
cortices) followed by Octochaetidae with four species (Eutyphoeus
gigas, E. assamensis and two unidentified species) and Moniligastridae
with two species (Drawida nepalensis and one unidentified Drawida sp.).
Diversity and evenness indices of earthworm at CTRL were higher as compared
to EXPTL site. Earthworm density in CTRL (1353.6 ind.m-2) was
significantly higher than EXPTL (857.6 ind.m-2) site [t = 2.039,
df = 66,P= .045]. Thus, negative impact of shifting cultivation on earthworms
density was observed [F2, 33= 5.607, P= .008]. Vertical
distribution showed significant (P > .05) decrease in earthworm population
with an increase in soil depth in both CTRL and EXPTL sites. The endogeic Drawida
sp. was the most versatile earthworm in temporal distribution.
Interpretation: The study clearly
indicates that the land use system in the form of traditional shifting
cultivation adversely affects earthworm density and diversity. The
destructive effect of shifting cultivation on earthworm is mainly attributed
to habitat disturbances, reduced food availability and changes in soil
physico ? chemical properties. However, the spatial distribution pattern of
an earthworm is not significantly affected by shifting cultivation. The temporal
distribution followed a general pattern where there is a rapid population
increase of earthworm after the onset of the rainy season.
Key words: Diversity, Earthworms, Endogeic, Shifting cultivation
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