chapter 8 - Shodhganga

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CHAPTER 8
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SUMMARY
The study is also based on the published literature on the lichen taxa of
Kumaun region (Nainital) available in different monographic, floristic and
revisionary studies of Indian lichens. The unique nature of the flora of Kumaun
region of Uttarakhand has attracted numerous botanists for collection of plant and a
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large number of collection records for higher plants are available, however, the lower
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group of plants are quite neglected from the area.
The present study is based on more than 2500 lichen specimens available from
the exhaustive field surveys, conducted in different areas in and around Nainital city
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and the preserved lichen material in different herbaria, collected in the past by
various botanists.
The complete identification of the lichen specimens revealed the occurrence
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of 89 species of lichens belonging to 46 genera and 20 families from the different
localities in and around Nainital city. The members of lichen family Parmeliaceae
with 11 genera and 24 species followed by Physciaceae with 8 genera and 16 species
exhibit their dominance in the area .Among the different lichen genera, Heterodermia
with 6 species and Caloplaca and Lecanora with 5 species each showed the
maximum diversity.
The epiphytic lichens grow luxuriantly on Quercus and other coniferous trees
of Cedrus deodara and Abies. Among the different tree Quercus semecarpifolia bears
the maximum diversity of lichens. The crustose lichens exhibit their dominance in the
area represented by 40 species followed by 38 foliose and 11 fruticose lichens. The
Kilbury Snow View and Chhattis Sheeree localities showed the maximum diversity
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of lichens with 28, 34 and 25 species, respectively while D.S.B. Campus and
Ayaratta showed poor to scarce growth of Lichens represented by 9 and 19 species.
High frequency of Bulbothrix setschwanensis, Leptogium delavayi, high
density and abundance of Phaeophyscia hispidula are recorded in the district. As
compared to other temperate regions of Kumaun the Nainital district exhibit less
diversity of lichens as most of the localities in the district are disturbed due to heavy
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pressure of tourist and other anthropogenic activities.
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The distribution pattern of lichens studied in more than 25 of eight major
localities in and around Nainital city clearly demarcated the whole city in three zone.
The localities situated in the centre of the city (D.S.B. Campus, Ayarpatta) showed
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poor to scarce growth of lichens represented by 9 and 19 species. The middle zone
comprised of Naina peak, Tiffin Top, Mangawali localities exhibit good growth of
lichens as compared to the inner zone represented by 21, 21 and 23 species,
respectively.
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The outer zone comprising of Kilbury, Snow View and Chhattis Sheeree
localities situated in the outskirts of the city showed 28, 34 and 25 species
respectively. The dense forest canopy coupled with higher altitude (2500-3000 m)
provide ample amount of moisture and shade which support many lichens to colonize
on trees, soil and rocks of the area. Though the Tiffin Top and Naina Peak area also
situated in middle zone at higher altitude (2000-2500 m), but show scarce growth of
lichens probably due to the fact that both these localities experience heavy tourist
pressure throughout the year. The heavy tourist pressure, fast pace of urbanization
and frequent botanical excusions by botany students from different universities,
resulted in exhaustive loss of diversity in and around Nainital city. Most of the plant
groups including lichens have been reduced to limited forest pactacts. The present
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distributional pattern of lichens clearly indicates the loss of habitat and decline of
plant diversity in and around Nainital city.
A large number of studies regarding use of lichens in biomonitoring
environmental pollution are known from different regions of the world. The lichens
growing on twigs can be used as an early warning system to detect a response to
changes in land management and nitrogen deposition. The twig lichens of oak species
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are used for carrying out biomonitoring studies in some temperate parts of the world.
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Similarly, the study area exhibit luxuriant growth of oak species. The lichens growing
on fallen twigs of Quercus leucotrichophora and Q. semecarpifolia in twenty
localities in and around Nainital city exhibit occurrence of 49 species of lichens
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belonging to 32 genera and 12 families.
Among the four diameter class of twigs (1.0-2.0 cm, 2.1-4.0 cm, 4.1-6.0 cm,
6.1-8.0 cm) the diameter classes of 2.1-4.0 cm and 4.1-6.0 cm of both species exhibit
maximum diversity of lichens represented by 32 each in Q. semecarpifolia and 34
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and 28 in Q. leucotrichophora. The foliose form of lichens exhibit their dominance in
all the four diameter classes of twigs of both the trees followed by the crustose and
futicose forms. Q. leucotrichophora exhibit maximum diversity of twig lichens in
Ramji Hospital area with 32 species followed by DSB campus and Chhattis Sheeree
with 28 and 27 species, respectively.
Q. semecarpifolia trees in Snow View area bear maximum number of twig
lichens represented by 31 species followed by Tower Compound and Tiffin Top with
29 and 28 species. Q. leucotrichophora trees in Plains View and Q. semecarpifolia in
Kumaun lodge sites bear the poor growth of lichens represented by 6 and 8 species,
respectively.
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The pH of all the diameter classes of twigs ranges from 6 to 8. The young
twigs having diameter class of 1.0-2.0, 2.1-4.0, 4.1-6.0 cm show low acidity (pH 7-8)
while the acidity increases (pH 6-7) in 6.1-8.0 cm diameter class of twigs. The
diversity of lichens decreases with increase in the diameter and acidity of the twigs.
The distribution and diversity of lichens on different classes of twigs of both
the commonly occurring oak species of the study area and their pH values can be
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used as base line record to monitor environmental changes in area overtime.
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Among the different lichen families the member of family Physiciaceae are
considered as „toxitolerant‟ which can withstand pollution and mostly grow in areas
having higher pollution level. The species of lichen genera Heterodermia and
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Phaeophyscea belonging to family Physiciaceae exhibit their luxuriant growth on all
the available substrata in the Nainital city. The dominance of pollution tolerant
species in the area clearly indicates the deteriorated condition of the environment.
The fruticose form of lichens such as the species of lichen genera Usnea, Ramalina
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and Cladonia, which are more sensitive to pollution and microclimatic changes
exhibit their occurrence in the outskirts of the city more or less in pollution free
areas.
Among the different growth forms of lichens, the study area exhibit dominance of
crustose lichens (40 out of 89 species) which are more tolerant to air pollution followed
by foliose and fruticose forms. The pollution tolerant crustose lichens act as a pioneer
colonizer in a new environment and replace sensitive species. The fruticose lichen
species are more common in outskirts of the city within more or less pollution free area.
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The available assessment of diversity and distribution of lichens and the
distribution of twig lichens in and around Nainital city will be used as a base line
record for carrying out future environmental monitoring studies in the area. The
lichens growing on twigs and their distribution pattern clearly indicates the extend of
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changes in environmental condition of the lake city of Kumaun.
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