Ecotones

ECOTONES
Presented By : Tuba Tahir

 What is an ECOTONE?
 The word Ecotone was coined by Alfred Russel Wallace, in
1859 who first observed the abrupt boundary between two
biomes.
 This word is formed as a combination of Ecology plus tone,
from the Greek tonos or tension, which means a place
where ecologies are in Tension.
 We can simply say that an ecotone is an area that acts as a
boundary or a transition between two ecosystems.

Definition:
 In simple words, An ecotone is a zone of junction or
a transition area between two biomes.
 An ecotone can be defined as a transition area where
ecological communities, ecosystems, or biotic regions coincide
and where two communities meet and integrate.
 Ecotones can be defined in various ways but in essence they
are dynamic boundaries and transitional areas between two
very distinct ecological habitats containing different
communities and physicochemical features.

Examples:
 Examples of ecotones include marshlands (between dry
and wet ecosystems), mangrove forests (between
terrestrial and marine ecosystems). The mangrove forest is
shown below.

 Other examples includes Grasslands (between desert
and forest), and estuaries (between saltwater and
freshwater)such as,
 Mountain ranges can also create ecotones due to the
changes in the climatic conditions on the slopes.

Features of Ecotones:
 It may be narrow or wide.
 Ecotone may be local (the zone between a field and forest).
 Ecotone can also be regional (the transition between forest
and grassland ecosystem).
 An ecotone may appear on the ground as a gradual
blending of the two communities across a broad area.

 Ecotone may manifest itself as a sharp boundary line.
This could be, for example, an area of marshland
between a river and the riverbank.
 An ecotone is a zone of tension (as it has conditions
intermediate to the bordering ecosystems).
 It could contain species that are entirely different from
those found in the bordering systems.

Formation of Ecotones:
 Changes in the physical environment may produce a
sharp boundary, as in the example of the interface
between areas of forest and cleared land.
 An Ecotone can be formed naturally through abiotic
factors such as changes in soil composition but can also
be created through the result of human interaction.
 Mountain ranges often create ecotones, due to the wide
variety of climatic conditions experienced on their slopes.
They may also provide a boundary between species due
to the obstructive nature of their terrain.

 Mont Ventoux in France is a good example of ecotone,
marking the boundary between the flora and fauna of
northern and southern France.
 Most wetlands are ecotones. The spatial variation of
ecotones often form due to disturbances, creating
patches that separate patches of vegetation.
 Different intensity of disturbances can cause landslides,
land shifts, or movement of sediment that can create the
vegetation patches and ecotones.

Biodiversity in Ecotones:
 As the area of ecotone is inevitably influenced by the two
bordering ecosystems, therefore there is a higher density of
organisms and variety of species in an ecotone.
 The ecotones (junction zones) often contain species of each
of the overlapping communities as well as some species that
have become adapted specifically for living in these zones.
 Some organisms need a transitional area for activities such
as courtships, nesting, or foraging for food.

 Edge effect:
 Edge effect refers to the changes in population or
community structures that occur at the boundary of two
habitats (ecotone).
 The increase in biodiversity of an ecotone is referred to as
the edge effect.
 Sometimes the number of species and the population
density of some of the species in the ecotone is much
greater than either community. This is called edge effect.
especially high biological diversity over 2006).

Ecocline and Ecotones:
 Ecotone is generally confused with ecocline but there is
difference in these two terms as,
 Ecocline is a gradation from one ecosystem to another,
with no abrupt boundary between the two.
 Ecotone is a transitional ecosystem between two varying
ecosystems, often well-defined. Such as (wetlands are
an ecotone between aquatic and terrestrial ecosystem).

Why are ecotones fragile?
 Ecotones are fragile, because they are unstable places
sensitive to environmental changes as they are among
the first places to show response to new environmental
stresses, such as climate change, increased grazing
intensity , or pollutants.

Role of ecotones:
 Ecotone can act as a “buffer-zone” protecting the
neighboring ecosystem from possible environmental
damage i.e., a wetland area could absorb pollutants
preventing them from seeping into a river.
 Ecotones provide an area for a large number of species,
they often experience influx from animals looking to
nest or searching for food.
 They may also be considered a habitat of
greater genetic diversity and serve as bridges of gene
flow from one population to another.

 Ecotones provide a sensitive indicator of global change.
 Ecotones contains as many fauna and flora at the limits
of their boundaries, thus any change to the local
environment will be felt by these species first. Their
activities therefore act as a barometer for change.

Ecotones

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Ecotones