Unit-
3 Management of Habitat
Habitat
Management
The most critical
aspect of wildlife conservation is habitat management. Habitat loss presents
the greatest threat to wildlife.
Five essential elements
must be present to provide a viable habitat:
1. Food,
2. Water
3. Cover
4. Space,
5. Arrangement.
1. The
need for food and water is obvious.
2. Cover
is needed not only to provide shelter from the elements and predators but also
to protect animals while they are feeding, breeding, roosting, nesting, and
traveling. Cover can range from thick weeds and brush to a few rocks piled
together.
3. Space
is necessary to avoid over-competition for food. Some animals also need a
certain amount of territorial space for mating and nesting. When crowded, some
species may develop stress related diseases.
4. Arrangement
refers to the placement of food, water, cover, and space in a habitat. The
ideal arrangement allows animals to meet all of their needs in a small area so
that they minimize the energy they use traveling from food to cover to water. Most
animals can be found where food and cover meet, particularly near a water
source. This is called edge effect.
Setting Back Succession: .
Ecological Succession - Definition
The most widely accepted definition of ecological succession is as
follows “ecological succession is a sequence of changes that occur in an
ecological system over time.” In simpler terms, it can be defined as the
sequence of colonization of species in an ecosystem from a barren or an
unfertile region of land.
Types of Ecological Succession
As mentioned above primary and secondary succession are the two
main types of ecological succession. The following stages of ecological
succession are discussed below:
1. There
are 2 types of succession,
·
Primary
·
Secondary.
Primary succession begins in environments that lack organic matter and
have not been altered by living organisms.
An example of primary succession would be areas of glacial retreat or
newly formed volcanic islands.
Secondary succession which is what we will focus on in this course,
begins in environments that have already been modified by the occupancy of
living organisms.
Plant
communities consisting of a diverse mixture of grasses, forbs, and scattered
shrubs are required by a variety of wildlife species. Early seral stages follow
some form of disturbance but can become dominated by shrubs and trees rather
quickly, especially in areas with abundant rainfall and relatively long growing
seasons, such as the southeastern United States. In the absence of natural
disturbance regimes, the quality and maintenance of these plant communities for
wildlife is largely dependent upon management.
Following practices are
carried out for early succession
1. Prescribed
fire,
2. Disking,
3. Herbicide
applications,
4. Mowing
Trimming/ cutting
.
Prescribed fire consumes vegetative debris, provides open structure at ground
level, and facilitates travel and foraging for wildlife throughout the field.
Burning
during
the dormant season may promote cool-season grasses if they are present in the
field. Burning in late March or early April generally promotes warm-season
grasses and forbs.
Late growing-season fire (September)
will reduce woody encroachment and may encourage additional forb cover.
Disking
promotes vegetation decomposition, provides open structure at ground level, and
generally promotes annual plant species. Disking in the fall and winter
stimulates more forb growth than disking in the spring, which will stimulate
undesirable nonnative warm-season grasses if present in the seed bank.
Selective herbicides can influence plant composition and can be used to
encourage grasses where forbs dominate, to promote forbs where grasses
dominate, and to reduce woody cover.
Mowing
during midsummer encourages additional grasses in fields dominated by forbs but
is not recommended for field maintenance because mowing produces thatch, which
limits the ability of several wildlife species to travel and forage through the
field, suppresses the seed bank, and destroys nests and young wildlife. Several
practices can be used in combination to meet specific objectives.
Succession should be set back every 2 to 4 yr,
depending on plant response and focal wildlife species. It is important to intersperse
disturbance in space and time, so that a variety of cover types are always
available, even to those animals with small home ranges.
Climax community
Succession can be viewed in several stages called seral stages. Each seral stage makes up a different type of plant
community. These stages if allowed to progress will eventually result in a
climax stage. A climax stage is a self-perpetuating community that is
relatively stable over several generations of the dominant plant species.
A climatic climax is regulated primarily by
climate. An Edaphic climax is regulated largely by soil conditions. Some
vegetation is vulnerable to catastrophic events and this is called a
Catostrophic climax. Chaparral vegetation in California is a good example of
this due to its propensity for wildfires. A disclimax community is held in a
stable, early successional condition by humans or other animals. In a subclimax
community, succession proceeds but is arrested permanently or for a long period
of time at the stage preceding the climax stage. A good example of this is a
fire climax, longleaf pine forest. If not for period fires the longleaf forest
would eventually give way to a hardwood dominated forest.
7. Over time, several
theories of succession have been put forth. Let’s discuss 3 of them which
include Monoclimax,
·
Polyclimax,
·
Climax pattern.
The
monoclimax theory the theory was formulized by Clements in the early 1900s. Clements
view the community as a superorganism where species composition and structure
is determined by regional macroclimate. Clements viewed succession as
deterministic, predictable and unidirectional, ending in 1 possible climax
community.
The
polyclimax theory was developed by Tansley in the 1920s. it
suggests that there may be more than 1 type of stable end point or climax
community. The theory suggests that local factors such as soil, climate and
disturbance greatly impact the composition and structure of the climax
community.
The
climax pattern theory was developed by Whittaker in 1953. This theory viewed the landscape as consisting
of environmental gradients and the vegetation that develops will be different
at each point along these gradients. Climax
vegetation will be a spatial pattern of vegetation that reflects the spatial
variation of the physical environment.
2.
Grazing, Logging mechanical treatment
The primary role of grazing in a wildlife management program
is to reduce the quantity of old-growth grass monocultures, allowing sunlight
to reach the lower growing forbs (weeds) which are important wildlife foods. In
turn, this process also creates structural diversity for nesting, brood
rearing, and escape cover.The primary role of grazing in a wildlife management
program is to reduce the quantity of old-growth grass monocultures, allowing
sunlight to reach the lower growing forbs (weeds) which are important wildlife
foods. In turn, this process also creates structural diversity for nesting,
brood rearing, and escape cover.
Prescribed
grazing/browsing couples the use of foraging livestock that are selective in
what they feed on with land management. It is a method of improving pasture
forage production and livestock performance, and maintaining quality wildlife
habitat by subdividing large areas of pastureland into smaller areas (paddocks)
and grazing those areas in a flexible rotation when the plants are ready
(mainly indicated by height). In this way, high quality forage is rationed out
to meet livestock needs, while plants already grazed are protected from being
eaten again until they have adequately recovered. It is the animals in these
systems that are acting the same as equipment or fire to affect the vegetation
in a plant community. When wildlife habitat enhancement is the planned
objective, ruminants can be a very effective and rewarding management tool.
Logging:
Logging, process of harvesting trees, sawing them into
appropriate lengths (bucking), and transporting them (skidding) to a sawmill.
The different phases of this process vary with local conditions and technology.
In mechanized modern logging, trees are felled by
crosscut saw or power-driven chain saw or, for trees of relatively young
plantations, by a machine that cuts the entire tree in one bite. Trees are then
cut into standard lengths and skidded to the mill by truck or tractor or
conveyed to a central point by cable, either high above ground (high-lead and
overhead skidding) or along the ground (groundline skidding). Helicopters and
balloons are also used to transport logs.
Local conditions may dictate uncommon logging
methods. In India, teakwood trees are killed by girdling (making a circular cut
around the tree through the outer bark and cortex to interrupt the circulation
of water and nutrients) and harvested several years later. Then, as is also
common in Nigeria, they may be floated down the river by raft. In several Asian
countries, timber may be transported by elephant.
3.
Advancing the succession
Succession is a periodic
process from nudation to climax community in a particular area. It
depends upon various abiotic factors to achieve the colonization stage. The
colonise species is called ‘Pioneer’ species.
Suppose a species invasion is occured in existing one and if that alien species
reached to climax by defending the early existing pioneer species then it would
be in advanced stage of succession process and it considered that existing
environmental condition favoured or facilitate the invade species to reach in
its advance stage of succession, because the new alien species is much advanced
than pioneer by utilising existing species’s environment.
4.
Cover
construction
Cover is the essential elements which provides space for
living. All types of vegetation and any other physical entities present in
habitat may considered as cover, through which the requirement of shelter for
animals fulfilled.
The position, height and shape may influence the habitat
quality wheather it is more suitable or not. Cover is different for different
species in wildlife, so according to the species types the cover would be
specific. To maintain the wildlife with balanced equilibrium cover construction
is necessary.
There are various ways through
which cover construction can be made easy.
i) Permanent Openings:
These are the area where ground
is covered with grasses as well as herbaceous plants that are helpful for
escape, nesting and brood rearing. These area provides food for birds and
mammals like cottontail rabbits, turkey and songbirds. Silviculture is one of
the technique which create the openings by planting annuals or perennials
accordingly with the soil character and need of wildlife.
ii) Brush Piles:
After logging,
placing the wooden log having 6-10 inches diameter and 6-8 feet long placed
parallel to each other with 8-12 inches gap between them, then by placing more
poles above it perpendicularly, loose stems can also be placed on second layer.
Making dense at middle by twigs and looser near edge became piles last longer.
Below the piles, there having a
plenty of space for quail, rabbit, turkey etc, the tunnel present in piles
helps them to escaping from predators.
iii) Shrub:
Allowing the tress and shrubs to
grow more densely which will ultimately helps in cover construction.
iv) Edge:
Edges are the areas where two
vegetations coincides and provide food resources. This type of cover can be
construct by planting in area having 20 feet wide, which should contain taller
plants near to other small vegetation. Near to the meeting site of two
vegetation trees are gets dropping down by hinge cutting where the droped trees
provide escape points or shelter for animals and songbirds, deer, turkey etc.
Other methods of cover construction includes nest
cavities for birds in trees, dead branch sites, dead portions of trees,
artificial best sties like nest boxes which can be placed in trees or around
ponds and marshes; travel corridors provide securely travel of animal which
requires large habitat for inhabiting in search of food, the travel corridors
may be streams, drains or rivers and over fence line.
5.
Preservation
of general genetic diversity
The cause of habitat loss such as over exploitation, grazing,
logging and through natural disaster like forest fire. Restoration is refers to
gaining of suitable habitat more compatible like before of existing degraded
habitat.
Before we think of habitat restoration, we
must think about two root aspects of habitat i.e. vegetation and
it’s linked part called soil. During the time of restoration it is
necessary to avoid the reuse of habitat by any means wheather it may be
logging, grazing and other intervention. Engagement of local people to the
targeted area which is going to be restore should be done with proper planning.
Priority should given to local people in scheme like replanting and reseeding.
As we discussing about the importance of soil quality and vegetation,
furthermore soil chemistry is very much vital i.e. soil moisture, it’s mineral content,
presence of microorganism and it’s typology. After considering this we must
choose proper vegetation which infact very much compatible for the area. In
terms of this suitable vegetation, local people should provided with reseeding
knowledge to increase the production of specific type of plants. Local people
should aware about the protection method i.e. which plants is to given how much
care and priority and what plant is for what purpose.
Though during the regaining of lost habitat, there been a sort
of restrictions for local people and due to this restrictions local people will
loose to getting necessary products like fuel, food, and fibre for thier use
and for thier livestock too. So alternate provision must accomplish for
compensation by giving benifit or access from nearby area.
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