Environmental Engineering Reference
In-Depth Information
to the north. At the eastern side lies the famous
Keoladeo National Park near Bharatpur, a World
Heritage Site. It also has two national tiger
reserves, Ranthambore (Sawai Madhopur dist.)
and Sariska Tiger Reserve (Alwar dist.) and a
small Tal Chhapar Sanctuary (Sujangarh, Churu
dist.). The Desert National Park (Jaisalmer dist.),
in Thar, is an excellent example of the ecosystem
of the desert and its diverse fauna.
Geographically, it includes the major part of
Thar Desert along north-western side, the Aravalli
Range running from south-west peak Guru
Shikhar at 1,722 m (Mount Abu) to Khetri in the
north-east and the termination of river Ghaggar
(originating in Haryana) into the sands of Thar in
the northern corner of the state. About three-fi fth
of the state lies north-west of the Aravallis, leav-
ing two-fi fth on the east and south direction. The
hill station Mount Abu is separated from the main
ranges by the River West Banas. The Thar extends
into the Indian states of Gujarat, Haryana and
Punjab. The north-western part of the state is gen-
erally sandy and dry with thorn scrub forests in a
band around the Thar between the desert and the
Aravallis. With the exception of Mount Abu, the
hilly Vagad region in southern most part on border
with Gujarat is the wettest region in Rajasthan and
the most heavily forested. The south-eastern area,
higher in elevation (100 to 350 m) and more fer-
tile, has very diversifi ed topography. In the south
lies the hilly tract of Mewar. In the south-east, a
large area (in districts of Kota and Bundi) forms a
tableland. To the north-east of this is a rugged
region (bad-lands) following the line of the
Chambal River. Farther north the state levels out;
the fl at plains of the north-eastern (Bharatpur dis-
trict) are part of an alluvial basin.
This region receives less than 400 mm of
rain in an average year. The western deserts
accumulate about 100 mm annually, while the
south-eastern part of the state receives 650 mm
annually, most of which falls from July
through September during the monsoon season.
Temperatures can exceed 45 °C in the summer
months and drop below freezing in the winter.
On average winter temperatures range from 8 to
28 °C and summer temperatures range from 25
to 46 °C. Average rainfall also varies; the
western deserts accumulate about 100 mm
(about 4 in.) annually, while the south-eastern
part of the state receives 650 mm annually,
most of which falls from July through
September during the monsoon season. The
Luni River and its tributaries are the major river
system of Godwar and Marwar regions, drain-
ing the western slopes of the Aravallis and emp-
tying south-west into the Great Rann of Kutch
wetland in neighbouring Gujarat. Eastern and
south-eastern region is drained by the Banas
and Chambal rivers, the tributaries of Ganga.
As regards insects, the species richness as per
'Shannon's Diversity Index' is the highest in
the order Lepidoptera (5.98) and lowest in
Odonata (0.41), probably due to scanty water
resources (Ramakrishna et al.
2010
).
Systematic Account, Distribution,
Habitat, Conservation Status
and Threats
Order: Odonata Fabricius, 1793
(Dragonfl ies and Damselfl ies)
Suborder: Anisoptera Selys, 1840
(Dragonfl ies)
Family: Aeshnidae Rambur, 1842
(Darners, Hawkers)
Genus:
Anax
Leach, 1815
(Subfamily: Aeshninae Rambur, 1842)
1.
Anax guttatus
(Burmeister, 1839)
Aeschna guttata
Burmeister, 1839.
Handb.
Ent
., 2: 840.
Anax mangus
Rambur, 1842.
Ins. Nevrop
.: 188.
Anax guttata
Brauer, 1866.
Reise d. Novara
Neur
.: 62.
Anax guttatus
Hagen, 1867.
Verh. zool.-bot. Ges.
Wien
, 16: 39; Fraser, 1936.
Faun. Brit. India,
Odo
., 3: 140-142; Prasad, 2004.
Fauna of
Desert National Park, Conservation Area Series
19: 51-58 (Girab, Barmer dist.); Subramanian,
2009.
Dragonfl ies of India, A Field Guide
: 37, 2
fi gs. (throughout Oriental region); Sharma &
Sewak, 2010.
Proceedings: Impact of Climate
Change on Biodiversity and Challenges in Thar
Desert
: 321-324 (Rajasthan).
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