**1. Introduction**

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Riparian forests (RF) growing along streams, rivers and lakes have special functions in the landscape as the interface between the terrestrial and the aquatic ecosystem (Malanson 1993). They are distinctly different from the surrounding lands because of unique soil and vegetation characteristics that are strongly influenced by free or unbound water in the soil. Riparian zones are usually a diverse mosaic of landforms, communities and environments within landscapes and they serve as a framework for understanding the dynamics of communities associated with fluvial ecosystems (Gregory *et al*., 1991; Naiman *et al*., 1993; Naiman *et al*., 2005). Being a transition zone between aquatic and terrestrial area where structural and functional properties change with space and time, discontinuously. Typical examples of riparian zones would include flood plains, stream banks and lake shores. The interfaces in riparian zones possess physical and chemical attributes, biotic processes, material flow processes, but they are unique in their interactions with adjacent ecological systems.. Riparian zones are habitats of critical conservation concern worldwide, as they are known to filter agricultural contaminants, buffer landscapes against erosion, and provide habitat for high numbers of species (John *et al*., 2005). The Riparian forests are habitats for a large number of forest species including many of the rare species that depend on water and as such serve as important areas for biodiversity (Gundersen et al., 2010; Darveau et al. 1995; Hylander 2006).

Riparian lands can also include intermittent streams gullies and dips which sometimes run with water. The vegetation ranges from emergent aquatic and semi-aquatic plants through to terrestrial understorey and canopy species (Parsons 1991). Further, the zone can be seen as an interface between terrestrial and aquatic systems and is described as a series of ecotones

© 2014 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

between these systems (Risser 1990). Riparian vegetation plays an important role in the maintenance of stream and foreshore stability. Streams and rivers are essentially dynamic systems, their path and flow constantly changes with the time (Warner 1983). The presence of vegetation in riparian areas acts to reduce the rate of change and therefore maintain a level of stability.

*al*., 1991). Types of propagules include sexually derived seeds as well as vegetative fragments (mechanically sheared or physiologically abscised branch or root segments) that can re-sprout to result in asexual propagation. Propagative dispersal typically occurs in a downstream direction along streams but may be wind-aided along lakes or reservoirs. Thus, hydrochory may occur in multiple directions along relatively stationary water bodies. Propagative dispersal by water is an effective adaptation of native plants but also provides a major mechanism for invasion by exotic weeds, of which noxious species can have severe ecological

Protection of Riparian Habitats to Conserve Keystone Species with Reference to *Terminalia arjuna* – A Case Study…

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Riparian vegetation changes continuously from the beginning of a river in the mountains up to the river mouth with the changing environmental parameters like altitude, humidity, soil conditions and also in the conditions of water like quantum and flow, temperature, pH, salinity. In a tropical countries, the riparian vegetation in a first order stream in the mountain may be ferns and other associated herbaceous plants in the rock crevices. When coming down, evergreen forest samples can be observed in the riparian zone as a quantum and the lateral influence of the water increases. Further going down the bed conditions of the river changes from rocky to sandy especially in the floodplains. Here the soil becomes looser, sedimentation rate will be high, and a good amount of alluvium can be found. In these areas the water influence on the vegetation may be more. Herbaceous, grass and hydrophytic plant commun‐

Ripairan areas acts as a migratory corridor and routes for many wildlife as it has been used for regular daily movements and seasonal migration. Riparian zones offers an three critical resources for wildlife: cover, food and water in one space. The undisturbed stands of age old woody species provide habitat for nesting birds resided in the forests. Riparian zones are utilized by wildlife as a sort of "natural highway". They are important to mammals and birds as they journey up and down the river during daily movements besides seasonal migrations. Much wildlife is found to be associated on floodplains than in any other landscape unit in most regions of the world (Klement and Stanford, 2002). In the Pacific coastal ecoregion (USA), for example, approximately 29% of wildlife species found in riparian forests are riparian obligates (Kelsey & West 1998). It provides habitat for more species of breeding birds than any other vegetation association. For example, of all bird species breeding in northern Colorado, 82% occur in riparian vegetation, and about half of south-western species depend upon riparian vegetation (Knopf & Samson 1994). Riparian areas in semiarid zones are critical in providing stopover areas for *en route* migrants (acting as 'dispersal filters'), and therefore affect the breeding success of northern bird populations (Skagen *et al.* 1998). In Europe, 30% of threatened bird species are inland wetland-dependent species and 69% of the important breeding areas for birds contain wetland habitats, primarily flood plains (Tiker & Evans 1997). In Switzerland, 10% of the entire fauna is restricted in its occurrence to riverine flood plains, although flood plains only cover 0.26% of the country's surface. Among 10%, 28% of the fauna frequently uses flood plains and about 44% is occasionally found in flood plains. A high proportion of the riparian obligates (47%) is listed as endangered, compared to 28% for the entire fauna (Walter

and economic impacts (Braatne *et al*., 2002).

ities will be abundant in these zones (Amitha, 2003).

*et al*. 1998).

**Figure 1.** Overview of Riparian forest in the banks of river Cauvery

### **2. Ecology and biodiversity in riparian forest**

Plant communities in large river flood plains are amongst the most productive and diverse in the world and frequently support higher number of plant species arranged in vegetation associations of greater complexity than surrounding landscaping units (Menges and Waller, 1983; Tockner and Stanford, 2002). Water level patterns are critical for the successful estab‐ lishment of new plants (both exotic and native species) following dispersal of seeds or other propagules by water, wind, animal vectors or other dispersal agents. Flow has been deter‐ mined as primary factors for determining plant community composition and structure along the riparian zone (Blom *et al.,* 1990; Ferreira, 1997). Many plant species depended particularly on the flow for dispersal of their propagules a process referred to as 'hydrochory' (Nilsson *et* *al*., 1991). Types of propagules include sexually derived seeds as well as vegetative fragments (mechanically sheared or physiologically abscised branch or root segments) that can re-sprout to result in asexual propagation. Propagative dispersal typically occurs in a downstream direction along streams but may be wind-aided along lakes or reservoirs. Thus, hydrochory may occur in multiple directions along relatively stationary water bodies. Propagative dispersal by water is an effective adaptation of native plants but also provides a major mechanism for invasion by exotic weeds, of which noxious species can have severe ecological and economic impacts (Braatne *et al*., 2002).

between these systems (Risser 1990). Riparian vegetation plays an important role in the maintenance of stream and foreshore stability. Streams and rivers are essentially dynamic systems, their path and flow constantly changes with the time (Warner 1983). The presence of vegetation in riparian areas acts to reduce the rate of change and therefore maintain a level of

stability.

96 Biodiversity - The Dynamic Balance of the Planet

**Figure 1.** Overview of Riparian forest in the banks of river Cauvery

**2. Ecology and biodiversity in riparian forest**

Plant communities in large river flood plains are amongst the most productive and diverse in the world and frequently support higher number of plant species arranged in vegetation associations of greater complexity than surrounding landscaping units (Menges and Waller, 1983; Tockner and Stanford, 2002). Water level patterns are critical for the successful estab‐ lishment of new plants (both exotic and native species) following dispersal of seeds or other propagules by water, wind, animal vectors or other dispersal agents. Flow has been deter‐ mined as primary factors for determining plant community composition and structure along the riparian zone (Blom *et al.,* 1990; Ferreira, 1997). Many plant species depended particularly on the flow for dispersal of their propagules a process referred to as 'hydrochory' (Nilsson *et*

Riparian vegetation changes continuously from the beginning of a river in the mountains up to the river mouth with the changing environmental parameters like altitude, humidity, soil conditions and also in the conditions of water like quantum and flow, temperature, pH, salinity. In a tropical countries, the riparian vegetation in a first order stream in the mountain may be ferns and other associated herbaceous plants in the rock crevices. When coming down, evergreen forest samples can be observed in the riparian zone as a quantum and the lateral influence of the water increases. Further going down the bed conditions of the river changes from rocky to sandy especially in the floodplains. Here the soil becomes looser, sedimentation rate will be high, and a good amount of alluvium can be found. In these areas the water influence on the vegetation may be more. Herbaceous, grass and hydrophytic plant commun‐ ities will be abundant in these zones (Amitha, 2003).

Ripairan areas acts as a migratory corridor and routes for many wildlife as it has been used for regular daily movements and seasonal migration. Riparian zones offers an three critical resources for wildlife: cover, food and water in one space. The undisturbed stands of age old woody species provide habitat for nesting birds resided in the forests. Riparian zones are utilized by wildlife as a sort of "natural highway". They are important to mammals and birds as they journey up and down the river during daily movements besides seasonal migrations. Much wildlife is found to be associated on floodplains than in any other landscape unit in most regions of the world (Klement and Stanford, 2002). In the Pacific coastal ecoregion (USA), for example, approximately 29% of wildlife species found in riparian forests are riparian obligates (Kelsey & West 1998). It provides habitat for more species of breeding birds than any other vegetation association. For example, of all bird species breeding in northern Colorado, 82% occur in riparian vegetation, and about half of south-western species depend upon riparian vegetation (Knopf & Samson 1994). Riparian areas in semiarid zones are critical in providing stopover areas for *en route* migrants (acting as 'dispersal filters'), and therefore affect the breeding success of northern bird populations (Skagen *et al.* 1998). In Europe, 30% of threatened bird species are inland wetland-dependent species and 69% of the important breeding areas for birds contain wetland habitats, primarily flood plains (Tiker & Evans 1997). In Switzerland, 10% of the entire fauna is restricted in its occurrence to riverine flood plains, although flood plains only cover 0.26% of the country's surface. Among 10%, 28% of the fauna frequently uses flood plains and about 44% is occasionally found in flood plains. A high proportion of the riparian obligates (47%) is listed as endangered, compared to 28% for the entire fauna (Walter *et al*. 1998).

#### **3. Ecosystem services of riparian vegetation** 1994). Riparian areas in semiarid zones are critical in providing stopover areas for *en route* migrants (acting as 'dispersal filters'), and therefore affect the breeding success of northern bird populations (Skagen *et al.* 1998). In

Riparian forests performs an array of functions in its buffer are which are beneficial to regional ecosystem to meet the some of their essential needs for their survival in the ecosystem. Some specific species stand unique in portraying their services in the particular ecosystem due to its morphological and phenological nature where their life cycle influences to protect stability of several flora and fauna in the ecosystem. Besides these functions, several species of riparian vegetation render services to the humans, as they provide several direct and indirect economic supports to run their livelihoods. areas for birds contain wetland habitats, primarily flood plains (Tiker & Evans 1997). In Switzerland, 10% of the entire fauna is restricted in its occurrence to riverine flood plains, although flood plains only cover 0.26% of the country's surface. Among 10%, 28% of the fauna frequently uses flood plains and about 44% is occasionally found in flood plains. A high proportion of the riparian obligates (47%) is listed as endangered, compared to 28% for the entire fauna (Walter *et al*. 1998). **2.1. Ecosystem services of riparian vegetation**  Riparian forests performs an array of functions in its buffer are which are beneficial to regional ecosystem to meet the

forests. Riparian zones are utilized by wildlife as a sort of "natural highway". They are important to mammals and birds as they journey up and down the river during daily movements besides seasonal migrations. Much wildlife is found to be associated on floodplains than in any other landscape unit in most regions of the world (Klement and

than any other vegetation association. For example, of all bird species breeding in northern Colorado, 82% occur in riparian vegetation, and about half of south-western species depend upon riparian vegetation (Knopf & Samson

Europe, 30% of threatened bird species are inland wetland-dependent species and 69% of the important breeding

ductive type of wildlife habitat. The Riparian areas act as a corridor for big game migratory

Protection of Riparian Habitats to Conserve Keystone Species with Reference to *Terminalia arjuna* – A Case Study…

Past civilizations came up on river banks, the followed generations used rivers as a source of water and food. The flood plains of the Indus, the Nile delta, and the fertile crescent of the Tigris and Euphrates rivers provided man with all his basic necessities. They can be considered the pillars of human civilization as they have formed the nuclei for human settlements from the very origins of mankind. Fishing is a major means of livelihood for the people who resided in and around the riparian zones. Many of the tribal's depend upon the river for fishing. The riparian vegetation decrease soil erosion and support silt thereby avoiding the pollutant input to the river. The shade, fruits and flowers offered by the riparian vegetations promotes the fish abundance in the aquatic ecosystems. The riparian vegetation provides Non Wood Forest Products for the dependent communities especially tribals who use the riparian forest to make their huts (Mainly *Bamboo* and *Ochlandra*), honey collections, timber, manure for farming and

The Cauvery river originates at Talakaveri (12° 25' N, 75° 34' E) in the Western Ghats at an altitude of 1341m. It is the 8th largest river in the subcontinent and ranks as a medium river

nearly 2.5% of the total geographical area of the country. The Cauvery river basin areas have a large floristic wealth enough to constitute as a separate phyto-geographic unit. The vegeta‐ tion of the entire peninsular India excluding Western Ghats is adequately represented in this tract alone (Jayaram, 2000). The known flora of the basin comprises 2037 species from 990 genera belonging to 180 families. The Cauvery river system harbors 1050 species belonging 128 families. 504 herbs (48%), 270 shrubs (25.7%), 170 trees (16.2%) other plant forms like climber, twinners etc constitutes 10%. The river basin is in human use since the beginning of the human civilization. As increase in the population growth intensified demands keep putting pressure on these riparian areas for agricultural development, recreational uses, commercial

The Cauvery river basin from headwater reaches to outlet exhibits remarkable habitat heterogeneity. The river is reserved by guilds of fish species. Headwater support more endangered fish which is confined to rock stream types having high gradients and predomi‐ nantly bedrock substrates (Smakhtin *et al*., 2006; Lakra *et al*., 2010). The riparian zone in the sacred landscape provides habitat for wildlife such as Asian elephants (*Elephas maximus*), Otter species (*Amblonyx cinereus*) (near threatened) (Shenoy, 2005), Endangered Nilgiri languar (*Trachypithecus johnii*) (Sunderraj and Johnsingh 2001), Indian civet (*Viverricula indica*), Lion-

area occuping

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on a global scale. The Cauvery River basin is estimated to occupy 81155 km2

animals between summer and winter range.

**6. General overview of Cauvery riverine ecosystem**

development, housing development and others.

**5. Social significance**

medicinal plants etc.

some of their essential needs for their survival in the ecosystem. Some specific species stand unique in portraying their services in the particular ecosystem due to its morphological and phenological nature where their life cycle

#### **4. Ecological significance** influences to protect stability of several flora and fauna in the ecosystem. Besides these functions, several species of riparian vegetation render services to the humans, as they provide several direct and indirect economic supports to

run their livelihoods.

The riparian plant species improves the microclimatic condition thereby allowing the other associated species to to grow in the community. The forks of old trees in the riparian zone provide wantage points to epiphytes. **2.2. Ecological significance**  The riparian plant species improves the microclimatic condition thereby allowing the other associated species to to

grow in the community. The forks of old trees in the riparian zone provide wantage points to epiphytes.

Figure 2. Epiphyte *Acampe praemorsa* growing on forks of tree species *Terminalia arjuna* and Orchids laden on tree branches of *Madhuca latifolia*. **Figure 2.** Epiphyte *Acampe praemorsa* growing on forks of tree species *Terminalia arjuna* and Orchids laden on tree branches of *Madhuca latifolia*.

Riparian species develops typical root modifications to withstand during the flood events. Such typical modifications of plant root systems are called as buttressed root systems. The buttressed root systems provide the strength to the tree species and to facilitates a suitable site to other riparian species to grow. Rivers combined with such root systems in conjunction with other herbaceous vegetation dissipate stream energy, resulting in less erosion and a reduction in flood damage. A 5 cm deep root system resists erosion up to 20,000 times better than bare soil stream banks. A woody root mat is the "re-bat' of stream banks. The riparian canopy provides organic matter via litter fall; surfaces of submerged leaves are sites of primary and secondary production by micro algae and bacteria, which can Riparian species develops typical root modifications to withstand during the flood events. Such typical modifications of plant root systems are called as buttressed root systems. The buttressed root systems provide the strength to the tree species and to facilitates a suitable site to other riparian species to grow. Rivers combined with such root systems in conjunction with other herbaceous vegetation dissipate stream energy, resulting in less erosion and a reduction in flood damage. A 5 cm deep root system resists erosion up to 20,000 times better than bare soil stream banks. A woody root mat is the "re-bat' of stream banks. The riparian canopy provides organic matter via litter fall; surfaces of submerged leaves are sites of primary and secondary production by micro algae and bacteria, which can rival that of phytoplankton and bactereophils in water column. The Logs of riparian vegetation play an important role in the dynamics of stream morphology and serve as substrates for biological activity by microbial and invertebrate organisms. On land the riparian stream ecosystem is the single most pro‐

ductive type of wildlife habitat. The Riparian areas act as a corridor for big game migratory animals between summer and winter range.
