Cacao (Theobroma cacao) is a crop of the humid lowland tropics produced largely by small-scale producers and often on farms with a canopy of shade trees. Where a diverse shaded canopy is used, cacao farms support higher levels of biological diversity than most other tropical crops. A host of viral and fungal diseases, loss of soil fertility, and numerous socioeconomic problems facing producers, often makes cacao production locally unsustainable. Continued clearing of new lands threatens biodiversity. Moreover, new frontiers for cacao expansion are rapidly disappearing. Such problems can be addressed by increasing the long-term productivity of existing cacao farms and restoring abandoned lands. Improved shade management offers guidance along this path. Institutions involved with cocoa should establish collaborations with groups concerned with development, environmental protection, and most importantly producers themselves to pursue a program of research, extension and policy initiatives focused on...

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Cacao Cultivation and the Conservation of Biological Diversity

Eighteen species of rodents are pests in agriculture, horticulture, forestry, animal and human dwellings and rural and urban storage facilities in India. Their habitat, distribution, abundance and economic significance varies in different crops, seasons and geographical regions of the country. Of these, Bandicota bengalensis is the most predominant and widespread pest of agriculture in wet and irrigated soils and has also established in houses and godowns in metropolitan cities like Bombay, Delhi and Calcutta. In dryland agriculture Tatera indica and Meriones hurrianae are the predominant rodent pests. Some species like Rattus meltada, Mus musculus and M. booduga occur in both wet and dry lands. Species like R. nitidus in north-eastern hill region and Gerbillus gleadowi in the Indian desert are important locally. The common commensal pests are Rattus rattus and M. musculus throughout the country including the islands. R. rattus along with squirrels Funambulus palmarum and F. tristriatus are serious pests of plantation crops such as coconut and oil palm in the southern peninsula. F. pennanti is abundant in orchards and gardens in the north and central plains and sub-mountain regions. Analysis of the information available on the damage and economic losses caused by rodents in rice, wheat, sugarcane, maize, pearl millet, sorghum, oil seed, legume and vegetable crop fields, horticulture and forestry, poultry farms, and rural and urban dwellings and storage facilities clearly shows that chronic damage ranging from 2% to 15% persists throughout the country and severe damage, sometimes even up to 100% loss of the field crop, is not rare. Several traditional and modern approaches and methods of rodent control are being used. The existing knowledge of the environmental, cultural, biological, mechanical and chemical methods of rodent control in India is reviewed. Considerable variations exist in the susceptibility of the pest species to different methods, particularly to rodenticides and trapping, their field applicability, efficacy and economics in different crops, seasons and geographical regions, behavioural responses of the pest species to these methods in different ecological conditions and their adoption by farmers in different regions of India. Environmental and cultural techniques, such as clean cultivation, proper soil tillage and crop scheduling, barriers, repellents and proofing which may reduce rodent harbourage, food sources and immigration have long lasting effects but are seldom adopted. However, their significance in relation to normal agricultural practices, intensification and diversification are discussed. Rodenticides, which provide an immediate solution to the rodent problem, form the major component of rodent control strategies in India. Poison baiting of rodents with zinc phosphide and burrow fumigation with aluminium phosphide are common in agricultural fields and recently Racumin (coumatetralyl) and bromadiolone have been introduced for the control of both agricultural and commensal rodent pests in India. Methods and timings of campaigns and successes and problems in implementation of rodent control are also reviewed.

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Rodent control in India

Ecology of the California Ground Squirrel on Grazing Lands

Agriculture is widely considered the single most important threat to biodiversity conservation and the greatest
driver of habitat destruction and change in Central America. Historically, agriculture has had a negative
impact on biodiversity conservation primarily through the expansion of the agricultural frontier, at the
expense of natural habitat. Today, the nature of the threat of agriculture to biodiversity conservation has
changed. While agriculture continues to drive deforestation in the few remaining, remote areas where the
agricultural frontier still exists, the main impact of agriculture is now due to the intensification of existing
agricultural systems (and the concurrent increased use of pesticides, fertilizers and other inputs, the loss of
hedgerows/live fences and natural habitats within these systems and the greater pressure on the remaining
natural resources) and to a lesser degree, changes in the configuration of agricultural landscapes.
A wide array of social, economic and institutional factors have contributed to (and continue to drive) the
expansion of the agricultural frontier, the intensification of existing agricultural systems and changes in
agricultural landscapes within the region. These include demographic and social factors, poverty levels,
land tenure, government policies and laws, international prices and consumption tendencies, expansion of
available infrastructure, market failures, technological factors, subsidies and tariff protection, and gaps in
information and extension services, among other factors. In particular, the growing population and increased
demand for land and agricultural products make it likely that the pressure to increase agricultural production
(either through the conversion of additional habitat to agricultural production and/or the intensification
of production of already existing agricultural areas) will intensify in upcoming decades. The eventual
implementation of CAFTA is also likely to strongly affect agricultural activities in the region through the
establishment of new laws that force exporters to comply with local environmental regulations and the
creation of new markets for some agricultural products.
Agriculture can affect biodiversity in a number of ways. The most immediate way in which agriculture impacts
biodiversity is through the conversion, destruction of modification of natural habitats, the fragmentation of
remaining natural habitat and the concurrent loss of landscape connectivity. However, other direct impacts
include the degradation of the remaining habitat though hunting, plant or animal extraction and entry by
domestic animals, the introduction and potential of non-native species (including GMO’s and potentially
invasive species), and the pollution of streams, rivers and near-shore marine ecosystems with fertilizers,
pesticides and fertilizers. In addition to these direct effects, agriculture may also impact biodiversity indirectly
through changes in ecological processes (e.g., water cycles, fires, pest dynamics), the invasion of exotic species
and changes in infrastructure that usually accompany agriculture and may further reduce natural habitat
availability.Different agricultural production systems vary in the extent to which they affect biodiversity, due to
differences in their requirement for new cleared land, pesticide and fertilizer use, susceptibility to soil erosion,
cropping intensity, area occupied, and spatial configuration in the landscape, among other factors. Although
the impact of individual production systems is likely to be site-specific and depend on the particular social,
economic, ecological and biophysical conditions, a few production systems have disproportionately affected
biodiversity in the region. These include cattle, coffee, banana and sugarcane production (all produced for
export), which have consumed large areas of land and fueled the expansion of the agricultural frontier into
new areas.
There are many ways in which the negative effects of agriculture on biodiversity can be mitigated or even
abated. Efforts to mitigate the impact of agriculture on biodiversity should focus not only on ensuring that
agriculture does not extend into existing protected areas or remaining remnants of natural habitats, but also
on finding ways to intensify production systems without the associated negative impacts on biodiversity and
encourage landscape-level changes which positively affect conservation efforts. A variety of technological
practices are available to enhance the conservation value of individual production systems or design and
manage agricultural landscapes for conservation goals. There are also many opportunities for mitigating
the impact of agriculture on biodiversity through changes in the legal framework, enhanced institutional
support and the implementation of market based approaches, however these issues are complex and not easily
or quickly resolved without considerable political will and government intervention. The key issue is how to
create the appropriate incentives, policies, laws and socioeconomic conditions under which these sustainable
practices can be applied and sustained, in such a way that the needs of the growing population are also met.

Assessing Linkages Between Agriculture and Biodiversity in Central America: Historical Overview and Future Perspectives

The distinctive features of reproduction in squirrels are the lack of allometric influences on the duration of reproductive investment; the strong allometric influences on offspring mass; and a trade-off between number and size of young, suggesting an important developmental component to reproduction. Lengths of gestation and lactation do not vary with body size but neonatal and weaning mass do. Apparently, the major constraint on reproduction in squirrels is not resources per se (food, calories, minerals, or water) but rather the length of time such resources are available. Squirrels adjust growth rate to fit the timing of resource abundance. Within the familial reproductive pattern, arboreal squirrels invest more into reproduction than do ground squirrels. Flying squirrels (Pteromyini) have a larger temporal investment into reproduction but a smaller energetic investment compared with other squirrels. Ground squirrels do not have a distinct reproductive profile, because marmotine and nonmarmoti...

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Reproductive effort in squirrels: ecological, phylogenetic, allometric, and latitudinal patterns

The Western Ghats squirrel, Funambulus tristriatus Waterhouse; the South Indian palm squirrel, F. palmarum Linnaeus and the black rat, Rattus rattus Linnaeus were observed to be causing much damage to cocoa in South India; the palm civet, Paradoxurus hermaphroditus Pallas and the bonnet monkey, Macaca radiata Geoffroy were causing minor damage. Monthly surveys made for one year in Karnataka showed that the percentage of damage caused by rodents was 29.0; that by civets and monkeys 0.4 and 0.3 respectively. In Kerala and one district of Tamil Nadu rodents were estimated to be causing 15% damage and civets 3%; no monkey damage was found.

Mammalian Pests of Cocoa in South India

Certains aspects de la biologie de la reproduction ont e*t6 £tudi£s chez un dcureuil des Ghats occidentaux, Funambulus tristriatus Waterhouse, de novembre 1977 a octobre 1979, dans le sud de 1'lDde (Vittal, 12°30'N, 74°80'E). Cet e"cureuil se reproduit toute 1'annee, avec un pic au cours de 1'ete", de docembre ä avril. La moyenne des portees a et6 de 2,5 ± 0,6, mais ä la naissance les portoes avec 2 jeunes ont 6t6 les plus froquentes (67%). II semble qu'il y ait des pertes apres Timplantation et du cannibalisme dans les populations naturelles de cet öcureuil. Le nouveau-ne* est aveugle et sa peau est rose et transparente. Le jeune commence a consommer des aliments sees et acquiert la couleur du corps de l'adulte des le 6 jour.

D. N. Mathew

Papers

Mammalian Pests of Cocoa in South India

Observations on the breeding biology of the Western Ghats squirrel, Funambulus tristriatus Waterhouse