Ecological analysis of The Satpura conservation area landscape through stratified field sampling and remotely sensed data
Production Manager, Avineon India, 605 HUDA Complex, Maitrivanam, SR Nagar,Hyderabad – 500038, AP, India
The study area for the current study is one of the oldest forest reserves, which has an established tradition of scientific management of forests. It constitutes a large contiguous forest block that harbours a community of plant and animal species typical of the central highland region.
The present study deals with the structure, composition, regeneration status and plant and animal diversity of the North and South Betul forest divisions in Madhya Pradesh. The tree density (No. of trees /ha) ranges from 323 to 507. Diversity of plant species tends to decrease in old growth stands, steep slopes, very disturbed areas i.e. areas around villages or recently felled coups, very dry areas, areas that have experienced fires in the recent past etc. Areas in valley flats, riparian areas, remote and less disturbed areas etc. show a high diversity. The regeneration status of sensitive species too shows a similar trend. The areas under assisted natural regeneration (ANR) show an improvement in just a year’s time, which proves that protection from biotic disturbance alone can help rejuvenate the degraded forests.
Forestry is dependent on an exhaustive spatial and non-spatial database. It incorporates information on geology, soil, climate, topography, vegetation types etc along with their growth behaviour, densities, utilization patterns, administrative setup, roads and communication, climate, demography, wildlife census etc. Creation of such a huge database is time-consuming and expensive. Moreover, information once collected has to be updated periodically. Over decades, foresters have evolved scientific methodologies to create and update this database. There is a constant quest for improvement of the existing methodologies by making innovative use of latest scientific knowledge and technology. Satellite remote sensing has emerged as an efficient source for generation of forestry crop data and the Geographical Information System as a strong tool to integrate the same with other components of the database, carry out analyses and generate maps and tabular outputs to achieve the desired results (Jadhav et al, 1992; Jadhav et al, 1988; Jadhav and Narain, 1985).
Satpura Conservation Area (SCA) represents the central Indian Highlands and is a heterogeneous mosaic of a large contiguous forest area that includes protected areas where resource use has been stopped or controlled for a long time and the managed forests where it is still on. Human use of resource is need-based and hence a strategy to keep people away from the resource is neither feasible nor viable. Keeping in mind that we cannot turn a Nelson’s eye to the unwise use of the resource, there is a need to build up a good scientific information base for large landscapes so that some immediate remedial measures can be worked to relieve the system from the stress. Hence emerges a need to zoom out from the stand levels to landscape levels, generate access to the natural history of the area, document the past management systems, assess the present scenario and come out with answers to queries which would serve as prescriptions with easy field applicability.
Conservation significance of the area:
Economic: The area represents the central Indian Highlands and the forests are economically amongst the most valuable of the dry deciduous types. Teak (Tectona grandis) also known as ‘king of timbers’ is the principal timber species. The largest size trees grow in the moister tracts of the Bori reserve in the north, no longer cut since the area is now included in the Satpura National Park and Bori Wildlife Sanctuary (M.P). There are several other less valuable timber species that grow along with teak. A small tract of sal (Shorea robusta) forests, another timber species among those most valuable that grow in India lies to the north-east, albeit on poor quality site, not harvested for a long time and now included in the PAs. The local forests and the forest dwelling tribal and non tribal communities economically are heavily dependent on these forests for their supply of small timber, fuel wood, bamboo, thatch grass, a variety of wild fruits, fibre, gum, seeds, medicinal forest produce, leaves, and fodder for grazing their cattle. Food items are derived from plant products with supplement of fish from streams. Leaves of the tendu tree (Diospyros melanoxylon) a nationalized produce collection provides large-scale employment and significant monitory gain for those engaged in collection activity. Tendu leaves support a multi-million-rupee industry.
Biological: SCA represents one of the largest contiguous populations of the critically endangered tiger estimated between 120-140 individuals. The other endangered species include mammals, birds, reptiles, amphibians fishes and insects. A number of endangered plants are documented with at least four pteridophytes in that category. A survey conducted in the Melghat forests has put up a list of more than 200 plant species of cultural and medicinal importance.
The two National Parks within SCA and portions of the four Wildlife sanctuaries represent ecological benchmarks, as they are least disturbed. The dry deciduous mixed forests represented in the SCA are among the finest and diverse within this type.
Ecological processes and functions: There are at least 14 regionally important rivers in the SCA; those in the north drain into the Narmada and the southern into the Tapi. These with their tributaries sustain life- human, plant and wild animals within SCA and local economy depends on these in context of catchment’s capabilities and soil conservation. The Tawa reservoir across the Denwa and Tawa rivers is the arbiter of regional economy in the Hoshangabad district within the command area. Some of the finest wheat and Soyabean crops are raised here that have changed the face of economy in this tract outside the SCA.
Recreational: Outdoor recreation has its own place in the societal values. Pachmarhi to the northeast and Chikhaldara to the south attract a large number of visitors on account of the salubrious climate, verdant landscape and scenic sites. The tourism corporations in MP and Maharashtra respectively have made considerable investments to promote tourism. The Satpura protected area complex around and below Pachmarhi and Melghat tiger reserve below Chikhaldara. Although the tiger is the major attraction, a wide range of animals, birds and plants constitute the recreational values.
Scientific: Since the protected areas are among the least disturbed tract, they are a repository of species richness and diversity; ecological processes and functions; diverse social systems, traditional lifestyles and wisdom. Opportunities for scientific research abound here.
Educational: Conservation education and nature interpretation opportunities in SCA are wide-ranging and diverse which can serve an equally diverse target groups. The significant aspect is the likely emerging support for conservation of biological diversity.
Cultural: The rich and diverse tribal societies, their traditions and customs are a repository of nature's wisdom. Most traditions and religious beliefs revolve around wild plants, animals, wilderness and living in harmony with nature. Several rock paintings believed to be more than 10000 years old hold the secrets of ancient civilizations. There are old forts and other historical sites, sites of religious pilgrimage that attract pilgrims from various parts of the country.
The study area covers the state of Madhya Pradesh and Maharashtra, covering the forest divisions of
Data and methodology:
An initial reconnaissance of the area was done to get acquainted with the area followed by its horizontal stratification. The stratification was based on variables like topography, vegetation, disturbance and moisture. This was followed by designing of transects, which were primarily of three types, viz. Rapid survey, detailed and vehicular. Other methods include plotless methods like Point Centered Quadrat, toe sampling etc.
Results and discussion:
The Satpura Conservation Area is a large block of Protected areas and Managed forests. The porosity of the area was more in Managed Forests while the Protected Areas were more or less contiguous blocks of forest (see Fig 1, 2 and 3). The predominance of non-forest areas and blanks in figure 1 and 2 clearly points towards the fragmentation of the forests due to biotic pressures that are much higher in Managed Forests than the Protected Areas.
Fig 1. The Study Area and its fragmentation
Fig 2. Forest Cover for Managed Forests
Fig 3. Forest Cover for Protected Area
In areas outside the PAs people tend to over-exploit natural resources leading to degradation of the natural resource base which also affects the water regime. In the long run this leads to serious difficulties for the rural society; as for example has been witnessed in several parts of the country where over-exploitation of natural resources has resulted in rampant deforestation. This has adversely affected the rural people, especially the women who have to walk greater distances to get water, fuel-wood and fodder. The density of the forest crop on an average was 323 trees /ha in Managed Forests as against 530 trees /ha in case of Protected Areas with greater diversity of crop.
A forest with high proportion of individuals in the recruitment class, points to the potential of the area to be sustaining more trees in the future. An age/size distribution, which decays nearly exponentially, reflects a population with many more juveniles than adults, and may be assumed to be self-replacing (Hall and Bawa, 1993).
Fig. 4. Size class distribution of Emblica officinale, Madhuca indica, Diospyros melanoxylon and Buchnania lanzan in PA and MF
The trees in the protected areas were composed of various girth classes as against the managed forest, which included trees of lower girth classes predominantly. The more biotically disturbed areas within Managed Forests were interspersed with and fragmented by habitations. Some degraded forests located at the M.P and Maharashra state boundary consisted of pole crop only. Lantana indica completely suppressed the growth of grass and herb species. Comparisons of g.b.h. (Girth at breast height) class distributions of the selected tree species, across the two areas, showed a significant difference in the population structure (see Fig 4).
For species like Tectona grandis, and Chloroxylon swietenia, plant parts other than seeds/fruits were harvested, thus these species had good regeneration in the managed forests. On the other hand, species exploited for human use, mainly fruits e.g. Emblica officinale, Madhuca indica, Buchnania lanzan, etc. showed poor recruitment in the managed forests indicating that the harvest of seeds and fruits, which form the seed bank for future trees affect the population of harvested tree species significantly. The branches of these trees (sometimes even whole trees) were badly cut to extract the fruits. Same was the case of Achar (Buchnania lanzan) trees but to a lesser extent. In the case of achar, the fruits were pre-maturely extracted in spite of the fact that unripe fruits could be sold at about half the price that they would fetch after ripening. Since, the seeds were almost totally extracted, their regeneration was very poor and only large trees (old) were found. In case of mahua, one reason for poor regeneration was the total collection of the flowers and fruits to brew liquor and for oil. It was only towards the end of the season, when the number of flowers and fruits reduced that the collectors stopped collecting. Only these contributed to the seed bank but fires and cattle grazing did not allow them to come up. This fact was well proven in the assisted natural regeneration (ANR) areas. These were the areas that were closed for collection and grazing and were protected from fires. There was a marked improvement in regeneration in the previous years ANR areas as compared to the current years. Poor recruitment of the non-timber species was also as the outcome of fires, grazing or of soil compaction. Teak, and tendu regeneration was high probably due to thinning and tending operations carried by the Forest Department thus promoting their growth. Bhirra too had a good regeneration probably because it was a hardy species. Extractive activities are most likely to be unsustainable if they result in killing and damage of the target species. "Aonla" and "Achar" trees were both felled and lopped in the Managed Forests during collection. The practice of felling trees would spell disaster not only in terms of regeneration of that species, but also in terms of irreplaceable loss of future source or income for the native population. Panwar and Mishra (1994), based on their study on fodder trees in Rajaji N.P indicate that trees, which are lopped, cease to flower and show total absence of regeneration. Lopping results in sap loss, attracts insect attacks, and ultimately results in plant mortality.
It was observed that the density of the recruitment class at the managed forest site for "Aonla" and "Achar" was almost negligible. A seed before germination has to pass through several stages during which it is susceptible to predation and to natural mortality. Apart from all these natural factors, man-induced pressures like extraction of seeds can push seed banks below the threshold level required to maintain the population. So even the above-mentioned higher percentage of harvest taking place in the study area may cause low regeneration.
There is a wide spectrum of floral and faunal features that occupy the Satpura conservation area. Occurrence of these varied forms are at times specific e.g. flying squirrel, giant squirrel, crocodiles otters, etc. to a particular region or at times it may be occupying a wide range of ecological niches e.g. crested serpent eagle, tiger etc. Rugged terrain along with boulders provides shelter to a number of animals on the lower slopes and valleys. The edges of habitations also constitute an important zone as it supports numerous avifauna and also chitals, nilgai, wild pig, hare etc. Old growth stands also form a rich habitat for the giant and flying squirrel. Of the top carnivores, the tiger is found to use all habitat types in the area but shows preference for dense woodlands and riparian habitat, which might offer suitable ambush for hunting. Bison and sambars are generally confined to upland forest in the hills. They make a seasonal shift to the lower slopes, valleys and plains in search of water during summer. Chitals have a preference for grasslands and marginal forests. Chausinga also prefer upland forest. Wild pigs, hare and nilgai remain confined to the forests adjoining the cultivated land. Carnivores subsisting on small prey like leopards and wild dogs are fairly evenly distributed. Serpent eagle prefers extensive undisturbed hilly area whereas bats are found in the wooded valleys. Peafowls and langurs are distributed over the whole area.
Wildlife use was found to be strikingly high in case of Protected Areas for reasons obvious. The only wildlife evidences that were encountered in case of managed forests were those of wild pig, hare, nilgai and on rare occasion, sambars. In many areas bears were sighted in good numbers during the fruiting season of Mahua, Achar etc. (i.e. summers). Parts of disturbed areas of managed forests that shared their boundary with Protected area (Melghat Tiger Reserve) in Maharashtra also had evidences of Leopards and sometimes Tigers as well.
Though the local people seem to be aware of the adverse consequences of their faulty practices, yet it continues due to several reasons. The season of Aonla harvest coincides with the period of agricultural activities, during which the people are hard-pressed for time. Thus, in order to gain maximum yield of Aonla in the least time possible, they tend to opt for the easiest means of fruit harvest, i.e., by lopping/felling which requires less time and is also labour intensive when compared to climbing the tree and plucking/beating. Achar is very valuable commercially, and is harvested when the fruit is still unripe, as ripe fruits are eaten by animals. The unripe fruit is difficult to harvest by the alternative methods of beating/plucking, and hence felling is the easier option for the people who aim to maximise their harvest.
In India, the problem of biotic pressures on natural areas is extremely high. The collection of non-timber-forest-products from protected areas is a problem faced in most PAs in the country. The results of this study present a picture, which is difficult to interpret and even more difficult to resolve. It is important that the management authorities handle the issue sensitively, keeping in mind the needs and compulsions of the people, when suggesting remedies to the situation.
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