4. A GLIMPSE OF OUR RESEARCH ACTIVITIES
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a) Behaviour & Sociobiology

Colonies of social insects (ants, bees, wasps, termites) a number of workers. The workers usually work for the well-being of their colony-mates and die without leaving behind any of their own progeny. How can natural selection, which is based on survival of the fittest, give rise to such altruism on the part of workers ? This question has bothered evolutionary biologists starting from the time of Darwin who termed it "...one special difficulty, which at first appeared to me to be insuperable, and facts that new nests are often initiated by one or a group of females (Fig.1) and that newly eclosed individuals may either leave to found new nests of their own, stay back and become workers or stay back and eventually become queens in their nests of birth (Fig.2).

By studying the behaviour of individually marked members of several colonies of Ropalidia marginata and R. cyathiformis we have discovered a large amount of inter-individual variability in behaviour. By multivariate statistical analysis of this variation, we have been able to classify the members of a colony into three behavioural castes which we have called Sitters, Fighters and Foragers (Fig.3). Of these, Foragers do bulk of the extra-nidal tasks of food gathering and have the most poorly developed ovaries. Sitters and Fighters have relatively better developed ovaries and share the intra-nidal tasks of building the nest and caring for the brood (Fig.4).

The first serious attempt to solve the puzzle of the apparently altruistic behaviour of the sterile workers in social insect colonies was made by W.D.Hamilton. He argued that, while producing offspring is one way of obtaining fitness, aiding genetic relatives is another. Hamilton's theory seems particularly applicable to the evolution of sterile worker castes in the Hymenoptera because they are haplodiploid and thus exhibit an asymmetry in genetic relatedness such that full-sisters are more closely related to each other than a female is to her offspring.

Our researches indicate however that this genetic asymmetry is broken down in R.marginata by two phenomena. First, queens are Polyandrous; they mate with more than one male, store sperm from each of their mates in their spermathecae and simultaneously produce different patrilines of daughters. In other words, not all daughters of a queen are full-sisters; colonies consist of a mixture of full-sisters and half-sisters. Because colonies of R.marginata are perennial, they often outlive their queens, providing opportunities for some of the workers to become queens. Such Serial Polygyny results in the simultaneous presence of different matrilines in a colony (Fig.5). We have shown that these two phenomena result in a sufficient decrease in genetic relatedness between workers and brood so that the advantage of haplodiploidy for the evolution of sociality postulated by Hamilton is largely forfeited in this species.

To test if there is variation in fertility between individuals which may make it "easier" for some individuals to accept worker roles, we isolated a large number of female R. marginata at eclosion and tested them for their ability to start new nests and lay eggs. The results of such an experiment showed that only about half the eclosing females are capable of doing so. We have also demonstrated that nests in which larvae are fed at a relatively higher rate produce a relatively greater proportion of females that can initiate nests on their own. However, in natural colonies, most individuals are workers and only a small number become queens whereas in our experiments about 50% of the individuals were capable of reproducing. The question remains therefore as to why only a small proportion of these 50% become queens in nature.

If wasps are programmed not to be sterile or fertile but to choose between solitary and group life and if the roles of queen and worker in the group mode are decided by chance factors, then it is possible that individuals who are programmed to "gamble" and join a group will do better, on the average, compared to those who shy away from the risk of group life and remain solitary. The fact that colonies of Ropalidia consist of several individuals who are capable of reproducing and that workers quite often succeed in driving away the queens of their colony and taking over the role of the queen lends credence to this gambling hypothesis ; females who stay back and work are not doomed to be sterile - some of them at least can become queens and inherit the whole colony which may be much more profitable than trying to start a new single foundress nest.

The role of demographic factors in promoting the evolution of insect societies has so far been relatively unexplored. We have therefore recently constructed a hierarchy of models to illustrate, within the framework of inclusive fitness theory, that demographic factors can select for a worker caste in social insects. The first model in the series shows that Delayed attainment of reproductive maturity lowers the inclusive fitness of a solitary foundress relative to that of workers. The second model shows that Variation in age at reproductive maturity makes the worker strategy more profitable to some individuals than to others and thus predicts the co-existence of single-foundress and multiple-foundress nests. The third model demonstrates the possibility of Mixed reproductive strategies so that, some individuals whose attainment of reproductive maturity is expected to be delayed can first act as workers and later switch over to the role of a queen or nest foundress. The fourth model shows that identical adult mortality rates can have different consequences for workers and solitary nest foundresses. This is because a solitary foundress will have to necessarily survive for the entire duration of development of her brood while a worker can hope to get proportional fitness returns for short periods of work. Workers may therefore be said to have Assured fitness returns.

These theoretical models have been tested using field and laboratory demographic data on R.marginata and demonstrate that such factors provide a consistently more powerful selective advantage for the worker strategy than genetic asymmetries created by haplodiploidy. We believe that a combination of empirical and theoretical investigations on a model system such as R.marginata, such as that pursued by us, can throw considerable light on the forces responsible for the evolution of altruism in insects in particular and animals in general.

Sociobiology has yielded major insights into the evolutionary basis of a variety of traits observed in animals - altruism and spite, selfishness and co-operation, parent- offspring conflict and sibling rivalry, to name a few. Somewhat more recently, these ideas have been successfully extended to plant systems as well. In collaboration with the University of Agricultural Sciences, the Centre for Ecological Sciences has begun to explore some key issues in plant sociobiology.

Polyembryony is a phenomenon where a seed contains two kinds of embryos - one obtained by the normal process of fertilization, and the other produced asexually. Using inclusive fitness models as well as explicit population genetic models, the conditions favourable for the evolution of polyembryony (in terms of maternal investments in the two embryos, the efficiency of conversion of resources into fitness etc.) were obtained. Brood reduction in plants, where some of the seeds in a developing fruit are aborted, is believed to result at least partly from sibling rivalry (antagonistic interaction between seeds). Polyembryony, whereby the parent plant can compensate for a loss of such seeds by producing additional embryos, can thus be viewed as a counter strategy to brood reduction. A survey of the reproductive characteristics and strategies of a large number of plant species revealed patterns supporting this conjecture; brood reduction itself as well as factors associated with brood reduction (e.g. larger number of seeds per fruit) were seen to be associated with polyembryony (Fig.6).

The conflict between developing seeds within a fruit over resources, allocated to the fruit by the maternal plant, has also been investigated by population genetic models. The intensity of conflict was seen to decrease with the increasing number of seeds per fruit. Since in single seeded fruits there is no competition, this result implies that the parental plant should favour production of either a single ovule, or very many ovules. In particular, conflict would be highest in two ovuled flower, indicating it to be a suboptimal choice. A frequency distribution of number of ovules per flower, obtained from over 600 plant species, strikingly confirmed this prediction.

b) Conservation Biology, Biodiversity & Forest Dynamics

In the area of conservation biology we have looked at biodiversity and its conservation both at the population-level and the community-level.

One of the earliest scientific studies on Asian elephant (Elephas maximus) ecology was carried out by our centre. This study of a southern Indian population looked at elephant-human interactions within the framework of the natural life-history of the elephant. It showed how movement and habitat utilization were interrelated with foraging behaviour of elephants, and that crop raiding was an extension of the optimal foraging strategy. A much higher propensity of adult male elephants to raid crops and kill people was the outcome of a "high risk - high gain" strategy by the males to enhance reproductive success; this had important implications for conflict management (Fig.7). The impact of the elephant-human interaction, in particular, the selective poaching of males for tusks, on population dynamics and viability was also analyzed. Several recommendations for elephant conservation and management emerged out of this study.

More recently, using the stable carbon isotope technique, we have shown that browse plants (C3 plant type) contribute a substantially higher proportion of protein for organic synthesis than do the grasses (of the C4 type). This again has important implications for the scientific management of elephant habitats. Our ongoing work on elephants includes a long-term assessment of elephant-vegetation interaction, population dynamics and behavioural changes caused by skewed sex ratios in the Mudumalai Sanctuary.

As part of a long-term programme of monitoring large mammals in Mudumalai Sanctuary, we have been censusing the populations of elephant (Elephas maximus), gaur (Bos gaurus), sambar (Cervus unicolor), chital (Axis axis), muntjac (Muntiacus muntjac), four- horned antelope (Tetracerus quadricornis) and common langur (Presbytis entellus) since 1989 (Table 1). This has led to the development of standard census technique for large mammals in tropical forests. In addition, a detailed study of the ecology of the dhole (Cuon alpinus), its population dynamics, movement patterns, home range size, hunting strategy and interaction with the principal prey species has also been carried out. This study is now being extended to the reproductive behaviour of this highly social canid.

The role of parasites as selective agents in moulding the life-histories of their host species has been recognized only in recent years. We have studied the faecally-dispersed parasites in twelve species of wild mammals in Mudumalai Sanctuary. More than any other factor parasite communities were found to be shaped by the host predatory pressure. Several results from the study would have implications for the management of wild mammal populations.

The disappearance of tropical forests, among the richest biological communities on earth, has stimulated world-wide interest in understanding their structure and dynamics. As part of an international network of large plots to study tropical vegetation dynamics on a long-term basis we have set up a permanent plot of 50-hectares during 1988-89 in the deciduous forests of Mudumalai Sanctuary. Within this plot nearly 26000 individual woody plants above 1 cm dbh belonging to 72 species have been identified, measured, tagged and mapped (Figs. 8 and 9). This plot is being annually re-censused to look at changes particular, the dynamics of this vegetation type is influenced by fire and large mammals such as elephants which damage trees.

Tropical montane forests are the most poorly studied among forest communities. In the Nilgiri hills the montane evergreen forests occur in patches, known locally along as sholas, along the folds of the hills and interspersed with extensive grasslands. Our studies on the past history of the shola forests and grasslands indicates that their extent has fluctuated considerably in the past as a result of climatic change. In recent centuries the forests have also been degraded by human activity. We have recently begun setting up permanent plots in the shola forests to study their dynamics in detail and come up with strategies for their regeneration (Table 2).

To complement the studies on forest dynamics we have also taken up phenological studies in these forests. Vegetative and reproductive phenology of trees in the deciduous forests of Mudumalai Sanctuary was monitored during 1988-90. Leaf flushing during the peak of the dry season much before the onset of rains seemed to be influenced by the need to avoid herbivory by insects which emerge after the rains. Flowering and fruiting phenologies were influenced by both abiotic and biotic factors. Reproductive success of an individual was maximized if it flowered during the peak flowering phase of the population (Fig.10).

Our studies on different taxonomic groups in the same locality have shown that diversity levels in these groups may not be necessarily correlated; for example in the district of Uttara Kannada bird and woody plant species richness is inversely correlated. We have also shown that amphibian species richness on the Western Ghats appears to peak in the district of Coorg, although the Western Ghats further south are believed to be on the whole much richer in biodiversity (Table 3).

We have also worked on the problem of objectively assigning conservation values at the level of taxa as well as localities. These developments are of basic theoretical interest; they have been fleshed out through concrete studies of bird and flowering plant diversity in the district of Uttara Kannada (Table 4).

c) Ecodevelopment

Degradation of natural resources like vegetation, soil, water and air is at the centre of environmental deterioration, threatening the sustainability of development and quality of life at global and local level. Sustainable development is at the top of the agenda of researchers as well as policy makers worldwide. The centre for Ecological Sciences has been working on the concept of participatory eco-development; aimed at participatory, equitable and sustainable development. All these three paradigms of development have received little or no attention of planners or policy makers. Even when there was awareness, an approach and methodology was lacking to incorporate the three components of Participatory equitable and sustainable development. We have developed a methodology for Participatory, equitable and sustainable development and field tested it in two village ecosystems in western ghat region, with the participation of local community and developmental agencies.

We aimed at understanding the features of natural resources and their use, involved the local community to identify the needs and to learn about traditional knowledge and practices, jointly developed a set of developmental options and modes of sustainable management of resources and monitoring of the process. One of the major lessons was that without genuine empowerment of local communities sustainable management of natural resources is not possible.

We have conducted several ecological studies that would contribute to promotion of ecodevelopment and sustainable management of natural resources.

1. The current practices of extraction of biomass like leaf biomass for manure purpose from forests is in a non-sustable way. Our studies show that a leaf lopping intensity of 50% had no negative impact on growth of trees.

2. Livestock grazing is considered to be one of the major factors contributing to forest degradation affecting regeneration. The fodder and grass balance studies in western ghats village ecosystem have shown that the availability of grass + fodder is inadequate and thus grass productivity from nearby forest lands is required. Thus there is a need to evolve grazing or grass harvesting practices such that forest regeneration is not affected. Studies are also being conducted to understand the sustainability of different grazing and land management practices on sustainability of grass productivity.

3. Revegetation programmes in India are dominated by a few exotic tree species, which do not meet the diverse biomass needs of local communities. A study to assess the performance of polycultural trials including local tree and shrub species, aimed at meeting different biomass needs is being conducted in a western ghat location. Some promising local tree species are being identified.

4. Biomass fuel consumption has been projected to contribute to forest degradation. Efficient use of biomass is one of the options to mitigate biomass shortages and to conserve tree resources. A large biomass conservation programme is being implemented. Monitoring of the biomass conservation programme in Western Ghat region shows that it is possible to conserve nearly 50% of the biomass currently used and at the same time improve the quality of life of rural women through the programmes like biogas and efficient stoves, both of which are environmentally sound.

5. To enable inclusion of a diversity of local tree, shrub, climber and lianna species, knowledge of their propagation methods is necessary. We have completed a study to identify the suitable propagation methods for several trees, shrubs, climbers and lianna species. Suitable methods for most species have been developed and problem species have been identified. Such locally valuable species do not receive the attention of conventional silviculturists and thus do not find any place in the revegetation programmes.

6. In India with a high human and livestock population densities and dependency on forests, it is hypothesized that forests are subjected to degradation due to anthropogenic disturbances. To assess the dynamics of vegetation status, nine forest locations with one ha plot each, representing different vegetation types and anthropogenic situations western ghats have been selected and vegetation status is being monitored annually for the last eight years and the results are being analysed.

7. India has vast extents of degraded lands. Prevention of further degradation, revegetation and meeting the growing biomass needs is one of the important challenges facing India. Currently, revegetation programme is mainly a forest department managed and exotic species dominated-conventional block plantation approach, which is wholly based on expensive artificial revegetation techniques. An alternate revegetation approach is emerging where natural regeneration is promoted in degraded lands either under a wholly community managed system or under joint management system involving local community and forest department. This low cost and participatory approach is being assessed in a multilocational study. Preliminary analysis shows the high potential of natural resources approach under community management.

8. Climate change is one of the major environmental problems facing the world today. Efforts are on to understand the factors contributing to climate change and to identify mitigation options. Deforestation is one of the contributing factors. We analysed the deforestation rates and carbon flows for Indian forests. The findings show that currently carbon emission rates from forestry sector are nearly offset by sequestration in forests under succession and forest plantations. Afforestation in degraded lands is shows to have a potential to offset about 50% of national carbon emission.

The Centre has sustained interest in evolving sustainable management practices for using natural resources and in evolving a methodology for promoting sustainable and participatory development under different ecological and socio-economic situations.


d) Environmental History

Our work in the field of environmental history spans both the geological and historical time scales.

In order to understand future vegetational and climate change as a result of human activity, it is important to first reconstruct past change in response to natural forces. In collaboration with Physical Research Laboratory (Ahmedabad) and Birbal Sahni Institute of Palaeobotany (Lucknow) we are currently studying climatic (monsoonal) and vegetational change in peninsular India during the late Quaternary period. The first phase of the study involved analyzing carbon isotopes in peat deposits of the upper Nilgiri plateau. Samples are dated by radiocarbon (14C) method, while the stable carbon isotope (13C/12C) ratio reflects the proportional contribution of C3 versus C4 plants, which in turn are good indicators of moisture availability. The results indicate a very arid period during the last glacial maximum (18000 years ago), a peak in monsoonal activity at the beginning of the Holocene (10000 years ago), and a weaker monsoon between 6000 and 3500 years ago. Further there is some evidence for a short, wet period around 600 years back which corresponds to the well-known Mediaeval Warm Period in Europe. With newer samples this study is being extended back to at least 40000 years before present through a combination of stable isotope (carbon, oxygen and hydrogen) and pollen analyses (Fig.11).

In a book entitled, "This Fissured Land : an ecological History of India" we attempt to interpret the entire panorama of India's ecological history from the time the land mass bumped onto the Asian continent, through its colonization by hunter- gatherers, agriculturists, industrial powers of Europe, to the present day. We do this by tracing the differential impact of different modes of resource use, and the accompanying economic, societal and ideological formations. The book provides an especially detailed picture of the forest history over the last two centuries.

This forest history is characterized by continual overuse and exhaustion of particular resource elements, followed by shifts towards elements which are either less profitable to exploit because of reasons such as difficulty of access, or call for much greater technological sophistication to permit exploitation. Such a sequence has been illustrated in rich detail by a study of environmental change in Nilgiris; a massif in Southern Western Ghats where an excellent data base is available in the form of maps and other documents beginning as early as 1830's (Fig.12).


e) Environmental Policy

Issues of environmental and development are especially complex in the Indian context given the diversity of modes of resource use which ranges over hunting - gathering, shifting cultivation, nomadic sheepkeeping, basketry and pottery to modern intensive agriculture and industry. It is therefore especially pertinent to enquire who benefits and who loses from the many different development initiatives, and who incur the costs of environmental degradation. Our group has actively pursued such enquiries to generate worthwhile insights. It has also participated in policy formulation with Government agencies, as well as worked with the voluntary sector and local communities in implementing new policies at the ground level.

An important theme of such activities has been the value of the considerable detailed understanding of the behaviour of complex ecosystems of each locality with the local communities. We have therefore worked with state agencies and the voluntary sector in devising appropriate institutions for the meaningful involvement of local communities in devising environmentally sound development strategies. This work has been focused on two village clusters in Karnataka Western Ghats, where we have investigated patterns of natural resource use, identified elements of non-sustainable use and involved local people in working out packages of environmentally more desirable schemes of development. This experience was then extended to work out the modalities for microplanning exercises for integrated development of wastelands on behalf of the National Wastelands Development Board (Fig.13).

We have also contributed to the forest policy debate, highlighting the non-sustainable use of forest resources both on open access public lands by local people, as well as in consequence of commercial demands on resources of reserved forest lands. We have proposed concrete alternatives, working with various groups including parliamentary committees. These alternatives have emphasized the primacy of environmental services and livelihood security of rural poor; priorities that are being increasingly emphasized (Fig.14).

Our group has been active in biodiversity conservation issues, especially in molding newer approaches like the Biosphere Reserves. We were involved in preparing the project document as well as delineating various zones for the country's first Biosphere Reserve in the Nilgiris (Fig.15). We have also been engaged to assess the countrywide Biosphere Reserve programme by the Ministry of Environment and Forests of the Government of India. Along with these official programmes with a thrust on fruitfully combining conservation and development; we have also emphasized the positive role of traditional conservation practices such as the sacred groves.

We have participated in several environmental impact assessment and drawn attention to ways they may be rendered effective, especially through a more open public process.


f) Human Ecology

Today humans are undoubtedly the most significant of actors on the ecological stage, and an elucidation of their role in bringing about environmental change is an important challenge. Much of the ongoing work at the Centre for Ecological Sciences addresses this challenge. This work encompasses theory, field investigations as well as applied action research and relates to historical as well as policy studies. At the theoretical level it has involved looking at people -natural resource interactions in terms of three major categories, namely, (i) ecosystem people, who gather/produce most of the resources they depend on through their own labour within a restricted resource catchment, (ii) biosphere people, for whom market permit access to resources of much of the entire globe, (iii) ecological refugees who have lost access to resources through the market (Fig.16).

The Indian society is a complex mosaic of ecosystem people, biosphere people and ecological refugees divided into thousands of endogamous caste groups. A significant proportion of these caste groups continue to pursue traditionally determined resource use strategies. We have investigated quantitatively the extent to which genetic as well as cultural transmission in the Indian society is constrained by the boundaries of endogamous caste groups. We have also documented the traditional patterns of partitioning of resources amongst different endogamous groups in a given locality. Such partitioning tended to ensure monopoly of access to specific resources for members of a given caste group in any locality. We have looked at how such a system facilitated co-operative action in contexts ranging from communal hunting and fishing to management of village woodlots and irrigation tanks (Fig.17).

Indeed the traditional systems had a number of elements of sustainable resource use, as well as conservation of biodiversity. We have documented such practices are still surviving based on field studies. These include, for instance, protection to sacred groves and restrained harvests from community woodlots. We have explored mathematical models of how human groups may have arrived at thumb rules of resource use through a trial and error process, and demonstrated that refugia, such as sacred groves constitute a potentially very viable element of a system of sustainable resource use (Fig.18).

We have documented current systems of resource management by tribal and rural societies, as well as industries in the modern sector and by the state apparatus. These investigations point to the very positive role local communities may play in conservation and sustainable use; not only through traditional practices like sacred groves, but modern practices like community based forest protection. Such forest protection has been spontaneously initiated by a number of village communities in Karnataka; and we have investigated the working of such systems and the lessons it has for the systems of joint forest protection and management being planned currently (Fig.19).
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