Impacts Of Human Disturbances On Vegetation Structure Biology Essay

Abstraction: Appraisals of human impacts on woods within protected countries will supply information on the causes and procedures of deforestation. We conducted a survey on the dependance of the local communities on wood merchandises and the impact on flora construction and diverseness in the dry deciduous Sal dominated woods of Similipal Tiger Reserve ( STR ) in Eastern India. We assessed human perturbation in 8 small towns utilizing two secret plans per small town: one secret plan was in the wood near to the small towns where the local people collected forest merchandises such as fuel-wood and fresh fish.

All woody species a‰?3.18 cm dbh ( diameter at chest tallness ) were for good marked and tagged. The control secret plan was farther off from each small town in a site where harvest home was non carried. We compared works densenesss, radical country, average tallness of trees, species profusion and diverseness in the survey secret plan and control secret plans.

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We assessed extraction force per unit area in the wood in the survey secret plans at 3-month intervals. The species profusion, diverseness, radical country and stand denseness and average tallness were lower in secret plans with ongoing perturbation compared with the undisturbed sites. Mean extraction force per unit area ranged from 1.

77-11 % and was positively correlated with small town size. This indicates that reaping affects forest construction and leads to loss of diverseness.


Forests have sustained human demands in the Indian subcontinent for centuries. Local communities have harvested the forest biomass in the signifier of fuel-wood, fresh fish, assorted works stuff, hunted wild animate beings for meat and for farm animal graze ( McNeely 1995 ; Ghimire & A ; Pimbert 1997 ; Hegde & A ; Enters 2000 ; Harris & A ; Mohammed 2003 ; Arjunan et Al. 2005 ; Meheta et Al. 2008 ) . It has been estimated that about 350 million hapless people and 84 % of tribal in India live in forested countries ( Mehta & A ; Shah 2003 ) , and significantly depend on the forest resources for nutriment and hard currency income ( Poffenberger et al. 1996 ; Hegde & A ; Enters 2000 ; Kutty & A ; Kothari 2001 ; Harris & A ; Mohammed 2003 ) .

However, due to the addition in human denseness near and within protected countries, the force per unit area on works and animate being populations has increased taking to forest debasement, loss of biodiversity and forest screen ( Kothari et al. 1989 ; Gadgil & A ; Guha 1992 ; Murali et Al. 1996 ; Somanathan & A ; Borges 2000 ; Rai & A ; Chakrabarti 2001 ; Silori & A ; Mishra 2001 ; Puyravaud & A ; Garrigues 2002 ; Anitha et Al. 2003 ; Rahmani 2003 ; Arjunan 2005 ; Arjunan et Al. 2005 ; Madhusudan 2005 ; Roessingh 2006 ; Karanth et Al.

2006 ; G. Shahabuddin & A ; Kumar 2007 ; Davidar et Al. 2007 ) . The strength and causes of forest loss and debasement demand to be identified and causes understood to explicate better direction and policy determinations.Similipal Tiger Reserve ( STR ) is a big protected country in the Northern Eastern Ghats ( Fig.

1 ) , in the Mayurbhanj territory of Orissa. It was declared a Tiger Reserve in 1972, but still more than 12,500 people live in the 65 small towns located within the Reserve and ain about 10,000 farm animal. The human impact has led to a progressive debasement of the forest, decrease in regeneration potency of the flora and loss of dirt ( Mishra et al.

2008 ) .The non sustainable extraction of biomass, together with grazing force per unit area from farm animal and combustion are the chronic perturbations to STR ( Parida 1997 ; Raut & A ; Behera 1997 ) . In this survey, we selected 8 small towns, 4 within the nucleus zone and 4 in the buffer zone of STR and investigated the impact of extraction of wood merchandises ; graze and other perturbation on the sal ( Shorea robusta ) dominated dry deciduous woods. We compared flora diverseness, construction and regeneration in one hectare secret plans situated near small towns with high degrees of extraction and grazing force per unit area with control secret plans in the same country but farther off from the small town in comparatively undisturbed woods. We so assessed extraction force per unit area in the secret plans near to the small towns at three month intervals over a period of 18 months. We tested the hypothesis that plots with higher degrees of human impact will hold lower diverseness, construction and degrees of regeneration than the control secret plans, and extraction force per unit area will increase in village size.

Study country

Similipal Biosphere Reserve ( 86A° 03 ‘ to 86A° 37 ‘ E and 21A° 28 ‘ to 22A° 08 ‘ N ) is a protected country spreads over 2750 sq. kilometer. across the territory of Mayurbhanj in the province of Orissa in Eastern Ghats. The modesty is divided into two distinguishable zones: the inner core zone of 845 km2. , besides designated as Similipal National Park, and encircling this, a outer buffer zone of 1904 km2 ( Fig. 1 ) ( Patro 1985 ; Das & A ; Das 1997 ; Setty & A ; Siddiqi 2007 ) . Similipal Tiger Reserve chiefly originated as a hunting land for royalty prior to India ‘s independency, and was declared as a ‘Project Tiger ‘ modesty in May 1972 to protect worsening populations of the Royal Bengal Tiger.

Vegetation comprises of semi evergreen woods, moist to dry deciduous woods and grass land and is dominated by Sal ( Shorea robusta ) ( Saxena & A ; Brahmam 1989 ; Misra 2004 ) . About 1076 species of workss belonging to 102 households, 42 species of mammals, 242 species of birds and 30 species of reptilians have been recorded in STR ( Rout 2008 ) . There are 61 small towns in buffer zone and four in the nucleus zone. The Santals, a Scheduled Tribe community, constitute more than half the population, and other groups are the Bhumijas, Bhuiyans, Hos and Gonds, who practiced agribusiness, and the Kharias, Mankidias and the Sabharas, who are mobile hunter-gatherers. They depend wholly on the wood and roll up NTFPs like honey, wax, rosin, arrowroot, siali fibre, herbal workss, fruits, foliages and flowers etc. and sell these to gain a support ( Das & A ; Das 2008 ) .

Materials and Methods

Estimates of extraction force per unit areaTo measure the extraction force per unit area on the woods, a sum of 16 one-hectar square secret plans were laid.

The location of these secret plans covered a representative country of Similipal Tiger Reserve. Eight of these secret plans were in woods where the villagers collected fuel wood and other wood merchandises. Eight of secret plans were controls and located in the same small town as the survey secret plans but farther off in the forest where resource extraction was minimum. Therefore each of the 8 small towns had one extraction secret plan and one control secret plan in its locality. In each of the 16 secret plans, all woody species & gt ; 10cm gbh were identified and tagged and their tallness recorded.

These workss were observed every three months and remotion of whole workss and works parts and the figure of new cuts and notches were recorded. The survey was carried out over a period of one and half old ages from November 2006 to June 2008 and a sum of six appraisals were made. An index of extraction force per unit area was formulated for each of the three month intervals. Extraction force per unit area was given as the [ ( entire figure of cuts*100/total figure of workss in the secret plan prior to appraisal ) / 3 ] to give monthly per centums for each small town every month ( Arjunan et al.

2005 ) . All the cuts and remotions were summed for the survey period and the one-year and monthly norms were estimated for each small town. The control secret plans were non assessed except at the initial period.Socio-economic correlatives of extraction force per unit areaAverage extraction force per unit area for each small town was correlated with the entire population of that small town as an index of small town size.

The small town statistics were obtained from the office of the Village Administration Officer. Comparison of extraction force per unit area by small towns with the highest and lowest average extraction over the 3 month period was made utilizing a non parametric Wilcoxon signed rank trial.


Extraction force per unit area of biomassThe average monthly extraction force per unit area was 6 % , and ranged from 1 % in Jenabil to 11 % in Gurguria ( table-1 ) .This shows that on mean 6 % of all trees had new film editings every month and most of the instances the whole works were removed. The buffer zone small towns like Gurguria, Makabadi, Naawna and Balarampur had really high degree of extraction force per unit area than nucleus countries small towns, There were significantly difference in the average monthly extraction force per unit area between the nucleus zone and buffer zone small towns ( Wilcoxon signed rank trial: P & lt ; 0.02 ) . The small town size was negatively correlated with root densenesss of each secret plan ( r= -0.

23, P & lt ; 0.05 ) . It bespeaking that larger small towns had fewer workss ha-1, bespeaking increasing force per unit area on woods with addition in village size. The average monthly extraction force per unit area is positively correlated with small town size ( r=0.43, P & lt ; 0.

05 ) . This determination suggests that the extraction force per unit area increases with as the size of the small town increases thereby prima to deforestation over clip due to increasing force per unit area from small towns.Speciess profusion, Species diverseness and radical countryThe survey resulted in certification of a sum of 93 species of trees, bushs and lianas belonging to 41 different households were recorded in survey sites, 71 species recorded in disturbed sites and 88 species in undisturbed sites ( Table 3 ) . About 55 species were common to both sites. There were 16 more works species in undisturbed compared with disturbed sites ( 74 species versus 58 in disturbed ) . Merely 21 species recorded in undisturbed sites were non found in disturbed sites but five species were recorded in disturbed sites were non found in undisturbed sites ( Table 6 ) . Species diverseness was lower in disturbed sites as compared to undisturbed sites ( Table 4 ) . The population denseness of different species varied in different sites and in every site Shorea robusta was dominant.

Tree denseness at different sites ranged between 528 in Balarampur to 1380 in disturbed sites and in undisturbed sites 760 in Makabadi to 2165 in Yamunagard ( Table 3 ) . Stem denseness significantly differed between two sites at that place were higher denseness in undisturbed sites than disturbed sites every bit good as the tree denseness were more in nucleus countries than buffer countries. In disturbed sites basal country were runing from 20.25 in Gurguria to 108. 47 in Jenabil and in undisturbed sites the basal countries differ in 33.52 to Jenabil 123.34 ( Table 3 ) . Basal country was significantly lower in disturbed sites ( 55.

28 ) as compared with the undisturbed sites ( 71.18 ) in ( Table 3 ) . This determination suggests that debasement is more in more populated countries.Uses of works portion for different intentOut of 93 species recorded in survey parts 90 species were used for fuel wood every bit good as other intents.


Forest debasement in Similipal Tiger ReserveThis survey clearly shows that there is intensive and on-going debasement of woods in Similipal Tiger Reserve due to anthropogenetic force per unit area.

The degrees of debasement were higher in the buffer zone as compared with the nucleus zone. The secret plans where people extracted forest merchandises showed a important lessening in works species richness, diverseness, radical country and average tallness, which are declarative of debasement ( Arjunan et al. 2005 ; Davidar et Al. 2007 ; Verma et Al. 1997 ; Kakati 1999 ; Ramesh 2003 ) .

Extraction force per unit area was variable between sites, and was related to size of the small town. Larger small towns had a greater impact on the wood. This degree of human force per unit area is non sustainable within a protected country.

The deciduous sal woods which cover most portion of the cardinal and eastern India ( Champion and Seth 1968 ) have been capable to high anthropogenetic force per unit area. Sal is a commercially of import tree and human intercession, such as controlled combustion have favored the laterality of sal and reduced the denseness of other works species ( Uma Shanker, 2001 ) . Sal wood has a good market in urban Centres such as Kolkata, and hence there is besides an on-going and illegal harvest home of sal trees, which are transported out of the woods by pes ( personal observation ) . In buffer zone, big trees were ringed and subdivisions of all sizes were notched to kill the tree. After taking the subdivisions the chief bole was cut and removed for sale in the urban countries ( Sahoo ain observation ) .

Even little trees and saplings were therefore destroyed, but for local usage. The intensive development of tendu foliages could besides do harm to the trees, but was non explored in this survey. Apart from the commercial extraction of sal trees, there is heavy dependance on the woods for fuel-wood ( Davidar et al.

2010 ) . In Similipal tiger modesty, the major beginning of energy is fuel wood, and all the families used fuel-wood for their domestic demands ( Davidar et al. 2010 ) . This is because there was no locally available replacement for fuel-wood for the local tribal communities. Fuel-wood is harvested in a day-to-day footing and is hence an of import cause of forest debasement. We documented that 90 out of the 93 species were harvested by the local people to provide their fuel-wood demands.

This state of affairs is prevailing throughout India and it has been estimated that approximately 85 % of the rural population in India depends on locally available fuel wood and agribusiness residues ( Natarajan 1997 ) . Therefore the local energy demands of the population demand to be considered if woods are traveling to be conserved for descendants. Switching cultivation and farm animal graze are other causes of forest debasement ( Sahoo unpublished ) . The dependance of the local communities on the woods for fuel wood, fresh fish, farm animal graze and other impacts such as firing the underbrush has been responsible for extended debasement of the woods.Impact on floraBasal country, root denseness, species diverseness, species richness and mean tallness of tree declined the extraction of fuel wood and has reduced species profusion and diverseness in Similipal Tiger Reserve, as reported elsewhere ( Verma et al. 1997 ; Kakati 1999 ; Ramesh 2003 ) , ( Rao et al. 1990 ; Vetaas 1993 ; Murali et Al. 1996 ; Ramirez-Marcial et Al.

2001 ; Kumar & A ; Shahabuddin 2005 ) showed that lessening the denseness and radical country, mean tallness of tree along the perturbation strength, ( Smiet 1992 ) basal country values may be related to the base perturbation index in different sites and different types of woods. So, in the to a great extent disturbed forest stand the basal country is lower than in the undisturbed bases, pattern of farm animal graze and treading affect on decrease of wild herbivores population, which indirectly affects flagship species such as tiger in protected countries ( Silori & A ; Mishra 2001 ; Madhusuddan 2004 ; Arjunan et Al. 2005 ) .


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