ecotone, wherein the biotic and abiotic interactions are taking place. The simplest
definition of riparian comes from Gregory (1991) “as the transition zone, an interface
between terrestrial aquatic ecosystems”. However, much before Gregory et al.
(1991), Lowrance et al. (1985) included organisms while defining riparian and
defined riparian as an ecosystem having the complex assemblage of organisms and
their environment existing adjacent to and near flowing water. Adding to the
definition of riparian was the water extension, which led Naiman and Decamps
(1997) to define riparian as a stream channel between the low and high water marks
and that portion of the terrestrial landscape from the high water mark towards the
upland where vegetation may be influenced by elevated water tables or flooding and
by the ability of the soils to hold water. Adding to it is the recent definition by a soil
scientist Ledesma et al. (2018) who defined riparian as “the area between the edge of
the stream and characteristic transition between organic and mineral soils”. The most
complicated definition comes by Ilhardt et al. (2000) as 3D ecotones wherein
interaction between terrestrial and aquatic ecosystems exists; this area extends
from groundwater to over the canopy top, beyond the floodplains, near to the slopes,
draining water also having lateral connections with terrestrial ecosystem along the
water course, and the width of the zone may vary accordingly.
A review by Dufour et al. (2019) comprehensively categorises riparian definition
into functional and structural type. The structural definition defines the riparian from
topographical perspectives, whereas functional approach defines considering the
interactions between two systems, viz. aquatic and terrestrial, in terms of hydrological, morphological, chemical and biological processes. The authors suggest that
most of the definitions of riparian use a functional approach. Defining the riparian
areas from structural perspective puts forth the geomorphological perspective of
riparian zone which deals with various fluvial features and landforms formed by
river deposits (Dufour et al. 2019). Dufour et al. (2019) emphasised that structural
approach is more used in delineating the riparian extent.
The diversified definition and suffixes of the word riparian still perplex
researchers, so it is important to come on one common note, thus accepting ecotone
as suffix to the word riparian and definition by Ilhardt et al. (2000), which not only
considers the biotic and abiotic interactions but also gives the spatial dimension to
the riparian ecotone, thus defining it completely. So further in the chapter, the
authors will be referring to riparian areas as riparian ecotone.
9.3 Components and Characteristics of Riparian Ecotone
Riparian ecotone, being the transition zone between the terrestrial and aquatic
ecosystems, comprises of the two important components, viz. land and water.
Further, talking in terms of ecology, this transition zones contain both abiotic (soil
and water) and biotic (organisms from microscopic to macroscopic fauna and flora)
components. These are thus the basic components of riparian areas; however, each
river has its unique riparian ecotone with their distinct geomorphology and ecology.
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S. Sharma et al.
definition of riparian comes from Gregory (1991) “as the transition zone, an interface
between terrestrial aquatic ecosystems”. However, much before Gregory et al.
(1991), Lowrance et al. (1985) included organisms while defining riparian and
defined riparian as an ecosystem having the complex assemblage of organisms and
their environment existing adjacent to and near flowing water. Adding to the
definition of riparian was the water extension, which led Naiman and Decamps
(1997) to define riparian as a stream channel between the low and high water marks
and that portion of the terrestrial landscape from the high water mark towards the
upland where vegetation may be influenced by elevated water tables or flooding and
by the ability of the soils to hold water. Adding to it is the recent definition by a soil
scientist Ledesma et al. (2018) who defined riparian as “the area between the edge of
the stream and characteristic transition between organic and mineral soils”. The most
complicated definition comes by Ilhardt et al. (2000) as 3D ecotones wherein
interaction between terrestrial and aquatic ecosystems exists; this area extends
from groundwater to over the canopy top, beyond the floodplains, near to the slopes,
draining water also having lateral connections with terrestrial ecosystem along the
water course, and the width of the zone may vary accordingly.
A review by Dufour et al. (2019) comprehensively categorises riparian definition
into functional and structural type. The structural definition defines the riparian from
topographical perspectives, whereas functional approach defines considering the
interactions between two systems, viz. aquatic and terrestrial, in terms of hydrological, morphological, chemical and biological processes. The authors suggest that
most of the definitions of riparian use a functional approach. Defining the riparian
areas from structural perspective puts forth the geomorphological perspective of
riparian zone which deals with various fluvial features and landforms formed by
river deposits (Dufour et al. 2019). Dufour et al. (2019) emphasised that structural
approach is more used in delineating the riparian extent.
The diversified definition and suffixes of the word riparian still perplex
researchers, so it is important to come on one common note, thus accepting ecotone
as suffix to the word riparian and definition by Ilhardt et al. (2000), which not only
considers the biotic and abiotic interactions but also gives the spatial dimension to
the riparian ecotone, thus defining it completely. So further in the chapter, the
authors will be referring to riparian areas as riparian ecotone.
9.3 Components and Characteristics of Riparian Ecotone
Riparian ecotone, being the transition zone between the terrestrial and aquatic
ecosystems, comprises of the two important components, viz. land and water.
Further, talking in terms of ecology, this transition zones contain both abiotic (soil
and water) and biotic (organisms from microscopic to macroscopic fauna and flora)
components. These are thus the basic components of riparian areas; however, each
river has its unique riparian ecotone with their distinct geomorphology and ecology.
204
S. Sharma et al.