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Insects are important representatives of the biodiversity of ecosystems. A majority of the insect species lives in freshwater environments, such as swamps, ponds, lakes, springs, streams and rivers these are called aquatic insects. There are about 8600 species of insects, falling under 12 orders, 150 families, known to inhabit diverse freshwater ecosystems. They play important ecological roles in keeping freshwater ecosystems functioning properly. There are many different kinds of aquatic insects as almost every type of freshwater environment habitat from puddles to river to lakes, including both lentic and lotic habitats, can belong to various species of aquatic insects. Aquatic insects are considered as model organisms in analyzing the structure and function of the freshwater ecosystem because of their high abundance, high birth rate with short generation time, large biomass and rapid colonization of freshwater habitat. The aquatic biodiversity gets affected by several factors such as industrial pollution or anthropogenic activities. Hence, this chapter is discussing about the diversity, habitats, roles, constraints and conservation of aquatic insects.

Lessons learnt from past experiences push for an alternate way of crop production. One such is Conservation agriculture (CA), which can be seen as a new way forward for conserving resources and enhancing productivity to achieve goals of sustainable agriculture. In recent past, progressive and significant efforts are made to develop, refine and disseminate conservation-based agricultural technologies across globe. Tremendous efforts on zero-till practices and surface management with crop residues for crop production were reviewed. This work was done at Department of Agronomy, Agricultural College and Research Institute, Tamil Nadu Agricultural University, Madurai -625 104, Tamil Nadu, India. A systematic cum integrative review of research work done in different parts of World, particularly in India was comprehended. Literature search was done during 2020. About 200 review and research papers were screened from various databases like TNAU e-library, ARCC journals, Google Scholar, Research gate and Scopus and 84 papers were used. This review article comprehensively documents major principles of CA along with extent and spread of CA across the globe. It also highlights CA in Indian perspective. Various merits and demerits were also discussed with literature support. This review paper discusses rising concerns of conventional agriculture systems with regard to its adoption, positives and negatives of conservation agriculture in promoting conservation agriculture in tropics.

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Habitat loss due to human activities and weather extrade is synergistically posing critical threats to the worldwide biodiversity main to irreversible extinction of diverse species. In wake of recent extinction, numerous forests are declared as protected areas wherein no greater human activities are allowed.However, the scope of these protected regions got broadened from mere conservation to poverty comfort and sustainable improvement within the course of the beyond decades. Though those protected regions appear to be supportive of the biodiversity conservation, numerous disputes and gaps have emerged that want to be addressed for powerful conservation and sustainable control in those protected areas. Although governmental regulations have addressed variety of these contests, handiest constrained achievement has been finished up to now. Therefore, similarly research wants to judge the performance of protected areas for biodiversity conservation and devise the mechanisms for powerful sustainable control of these protected areas.