Introduction

Landscape constitutes a heterogeneous area comprising of different interacting ecosystems, including land (mountains, hills, soil, forests) and water (streams, rivers, oceans, lakes, etc.). These interactions among the components of ecosystems result in the flow of nutrients, minerals and energy, which contribute to the functioning of the landscape. Watershed, an integral part of any landscape, can be defined as an area that supplies water by surface or subsurface flow to a given drainage system or body of water, be it a stream, river, wetland, lake or ocean (World Bank 2001).
Forests and water are intrinsically intertwined as forested watersheds have significantly different behaviour from non-forested watersheds as the former is more helpful in infiltration of rainfall. The nature of vegetation in the catchment is important in ground water recharge, runoff and soil moisture conditions, soil erosion and soil quality (Biao et al. 2010; Bruijnzeel 2004). Despite the fact that the forest-water relationship is not all that simplistic, being an outcome of many factors of climatic, edaphic, geological and biological  nature,  the importance of forests in water conservation has been accepted globally (Bradshaw et al. 2007; Makarieva et al. 2006).

India has a well established ancient tradition, more in the highlands, of protection of patches of forests as sacred. Though these forests are devoted to gods with many taboos associated with tree felling in such areas, the intimate association of such sacred forests or sacred groves with water bodies, in the form of streams, rivers, ponds and lakes, swamps or springs, is a well acknowledged fact. Hydrological services to village communities from well preserved sacred groves are highlighted in several studies (Chandran & Gadgil 1998; Gokhale & Pala 2011; Malhotra et al. 2001). Based on studies in the Himalayan states of Himachal Pradesh and Meghalaya, Khiewtam & Ramakrishnan (1993) and Singh et al. (1998) reported the role of groves in reducing run-off and soil erosion, preventing landslides and in conferring  ecosystem stability. Vertical stratification in the untrammelled humid tropical forests along with the extensive root network covered with leaf litter are linked to increased soil percolation, recharge of ground water (Khiewtam & Ramakrishnan 1993). The stored precipitation in the underlying strata (saturated and vadoze zone) are released to the streams making them flow perennially. Natural forest soils with greater porosity and low bulk density retain more moisture for longer duration even after the stoppage of seasonal rains. This fact is evident from the relatively less disturbed sacred groves which are often sources of fresh and clean water for many village communities (Godbole & Sarnaik 2004). The watershed values of especially swampy sacred forests, dominated by members of Myristicaceae, occurring in isolation in Western Ghats of Kerala and Karnataka, are home to several rare and threatened floristic and faunal elements that prefer aseasonal tropical forest conditions (Chandran & Mesta 2001; Chandran et al. 2008, 2010). Chandran & Gadgil (1993) emphasized the role of sacred groves as safety forests in otherwise human impacted landscapes of Uttara Kannada district of Karnataka, especially on account of their hydrological and biological importance. The British rulers had shown some consideration of the preservation of the evergreen kan forests of Uttara Kannada, on account of their hydrological importance, as reflected in the pronouncement of the Government of Bombay (1923). All such studies associating perennial water sources with sacred groves were of more of general nature, without any quantifications or evaluations involving local water cycles with biodiversity and livelihoods.

The Western Ghat mountain chain, one of the 34 global hotspots of the world, running parallel to the west coast of the country, is home to numerous sacred groves. Their ecological characters range from evergreen to dry deciduous forests, semi-deciduous and swamp areas thus providing varied ecosystem services (Bhagawat et al. 2005; Chandran et al. 2010; Gunaga et al. 2013; Rajendraprasad et al.1998; Ray et al. 2012). A large scale land cover change in recent times is altering the ecosystem structure influencing the respective ecosystem’s goods and services.  Quantification of linkages of ecosystem structure with hydrological and other concurrent services helps in mitigating land cover changes and hence the conservation of ecosystems. In this context, a comparative assessment of two watersheds (with and without sacred forests) through ecological, hydrological and socio-economic parameters was undertaken to understand the linkages of landscape structures of watersheds with hydrological services and also local livelihood.