1. DIVERSITY OF ANT SPECIES ACROSS A GRADIENT OF LAND USE TYPES IN
WESTERN GHATS OF NILGIRI BIOSPHERE, KARNATAKA
N.G. Kumar1, P. Nirmala1, T.M. Musthak Ali1 and A.N.Balakrishna2
1. Department of Entomology
2. Department of Agricultural Microbiology
University of Agricultural Sciences, GKVK Campus,
Bangalore-560065, Karnataka, India.
INTRODUCTION Table 1: Distribution and diversity of ant subfamilies in different land use ecosystems
during pre- (February) and post monsoon seasons (November).
Land use affects species numbers of both plants and animals
and has an impact on species composition by changing the
Number of ant species
landscape. In tropical agriculture, plantation and forestry are
leading land use that affects biodiversity as their coverage is Subfamily Natural forest Grassland Cardamom Acacia Coffee Paddy
rapidly expanding. The soil macro-fauna also known to
respond quickly to habitat disturbance and also season and Pre Post Pre Post Pre Post Pre Post Pre Post Pre Post
hence can be used bio-indicators of ecosystem integrity. Dolichoderinae 1 - - - 1 - - - - - 1 -
Dorylinae 1 - - - - - 1 - - - - -
Formicinae 4 2 2 2 5 1 4 - 7 - 3 2
MATERIAL AND METHODS Myrmicinae 7 2 2 1 6 1 4 1 5 2 5 1
Ponerinae 2 3 5 3 4 1 3 5 - 4 4 4
Study site: Koothi village, Somvarpet Taluk, Kodagu District,
Karnataka, India [Nilgiri Biosphere Reserve (Westernghats)] Total 15 7 9 6 16 3 12 6 12 6 13 7
Annual rainfall: 2500 to 3500mm Simpson Diversity index 0.82 0.92 0.74 0.61 0.72 0.48 0.68 0.67 0.61 0.19 0.59 0.81
Seasons: Pre- and Post-monsoon seasons (February and
November)
Ecosystems sampled and sampling points: Natural forest (9), Table 2: Abundance and Distribution of ant species in different land use ecosystems during
Grassland (8), Acacia plantation (6), Coffee (16), Cardamom February and November months.
(13) and Paddy (8).
Method followed: Pitfall trap method
Ant Species Natural forest Cardamom Acacia Coffee Paddy Grassland
Aenictus sp. (56) (2)
Anochetus graeffei (12)
Aphenogaster sp. (83) (2)
Camponotus sp1 (1) (3) (5) (1)
Camponotus sp2 (1) (1) (6)
Camponotus
* (2) * (2)
Paddy angusticollis
Camponotus compressus (1) * (1) (4)
Study site
Camponotus parius (23) (6) (16) * (1) (1) (4) (27) * (3)
Camponotus sericeus (6) * (2) (1) (1) (13) * (2)
Crematogaster sp. (89) (23) (24) (3)
Diacamma sp2 (1)
Diacamma cyaneiventre (68) * (3) (51) (92) * (2)
Diacamma rugosum (11) (8) * (2) (10) * (18) * (2) (19) * (2) (19) * (10)
Harpegnathus saltator (1)
Cardamom plantation
Coffee
Leptogenys dimunata * (1) * (1) * (5)
Leptogenys chinensis * (1) * (1) * (1)
Mesoponera sp. (1)
Natural forest
Monomorium florricola (2)
Monomorium sp. (1) (3) (2)
Odontoponera sp. (4)
Odontoponera transversa (5) * (2) (1) * (2)
Acacia plantation
Oecophylla smaragdina (6) (7) (11)
Pachycondyla nuda * (4) * (1) * (13)
Sampling protocol
Pachycondyla luteipes * (1) * (1) (8) * (2)
Pachycondyla sulcata (3) ( 7)
RESULTS Pheidole sp1 (53) * (2) (143) * (13) (29) * (2) (213) * (62) (126) * (3) (1) * (42)
Pheidole sp2 (23) (89) (165) (122) (32)
The cardamom plantations harboured 16 species of ants
Pheidolegeton diversus (126) (1)
belonging to four subfamilies during pre-monsoon season
and it was followed by natural forests (15 species with five Polyrhachis illaudata (1) (2)
subfamilies), paddy fields (13 species with four Polyrhachis rustrata (2)
subfamilies), coffee plantations (12 species with two Tapinoma sp. (3)
subfamilies), acacia plantations (12 species with four
Technomyrmex sp. (2) (1)
subfamilies) and grasslands (9 species with three
subfamilies). Tetramorium sp. (3) (1) * (1)
The members of subfamilies Formicinae and Myrmicinae Total number of species 15 6 16 4 12 8 13 6 10 5 8 6
were active in all the ecosystems.
The Simpson's diversity index was maximum in natural Note: February collections
forests (0.82) followed by grasslands (0.74), cardamom * November collections
Figures in parenthesis indicates abundance
plantations (0.72), acacia plantations (0.68), coffee
plantations (0.61) and paddy fields (0.59).
On the other hand, the results of post-monsoon season
indicated that the members of the subfamilies
ACKNOWLEDGEMENT
Dolichoderinae and Dorylinae were absent.
Formicinae ants were not active in coffee and acacia The authors are grateful to TSBF-CIAT/GEF/UNEP for the financial support to carryout the
plantations. The species composition in all the ecosystems investigation.
was reduced to almost 50%.
CONCLUSION REFERENCES
Significantly reduced ant species in intensive cropping Forgarait, P.J., 1998, Ant biodiversity and its relationship to ecosystem functioning: A review,
ecosystems compared to natural forest ecosystems. Biodiverse. Conserv. 7: 1221-1244.