Habitat creation Flashcards
What is habitat creation?
The management and creation of a habitat is an increasingly important part of environmental management.
Unintentional habitat creation
When a habitat is created as a consequence of other human activity, like creation of a reservoir.
These may have resulted in the destruc tion of a former habitat or a former habitat becoming unsuitable
for original inhabitants
Intentional habitat creation
Where habitat is created deliberately for wildlife conservation, like wetalnds, wildflower meadows etc.
These may have already existed or may have been altered through management like land use change or rewilding.
when planning habitats, a range of factors must be considered in order for it to be successful
habitat area and shape including biological corridors, habitat diversity and vegetation age structure, water and light availability.
Habitat area
Must be large enough to support viable populations, must have suitable breeding areas to maintain genetic diversity.
examples where habitat area is important
Monkeys need trees that produce fruits at different times of the year, so the habitat must be big enough to support this.
Some species, like frogs or newts, need a smaller habitat. Frogs and newts, for example, benefit from a small pond without fish species to prey on their eggs.
Biological corridors
Are a strip of forest/suitable vegetation which is not removed (or has been replanted) to allow separate populations of animals to migrate and interbreed. They link areas of the same habitat to allow dispersal, particularly of breeding individuals.
THEY ALSO ALLOW ANIMALS TO AVOID HAZARDS WHEN MOVING BETWEEN AREAS
Biological corridors can combat the impact of forest fragmentation
Forest fragmentation occurs when forests are destroyed; the removal of trees causes forests to become broken up into small interconnected areas, and this poses a serious threat to populations, as it promotes interbreeding due to isolation, narrowing the gene pool, which makes genetic abnormalities more likely and population survival less likely.
Habitat shape
perimeter of any habitat has a strip where conditions are a combination of the two habitat ons either side. Some species thrive here, whilst others survive and some need the area.
SO WE MUST PRESERVE AS MUCH OF THE CORE HABITAT AREA AS POSSIBLE
Vegetation age structure
in some habitats, the dominant vegetation lives for a long time and the younger trees grow in clearings made by older trees dying.
Because younger woodland may not have any natural clearings for a long time, the canopy will be very dense, light levels will be low and biodiversity will decline, reducing wildlife value of the woodland. To counteract and prevent this, we create similar conditions by selectively felling trees in order to make clearings and promote younger growth, leaving decaying wood to provide habitats.
Niche
A niche is an organisms specific role or position in its ecosystem, it includes its habitat, interactions, with other organisms and its contribution to ecosystem function and stability.
Habitat diversity
Natural habitats have local variations in conditions, producing a greater range of possible niches. This increases biodiversity as different species advertise the areas to which each is best adapted.
Light levels
Shading effect of dense tree cover inhibits the growth of plants on the woodland floor; this can be reduced by selective;y felling trees to create suitable conditions for smaller plants that need more light.
Water depth
Aquatic flora and fauna often colonise particular parts of water depth:
taller plants often dominant as they can access more sunlight, and plants with emergent vegetation can only support their weight in shallower water where roots have a firm hold in the sediment.
AS WATER DEPTH INCREASES, ROOT ANCHORAGE AND NUTRIENT ABSORPTION BECOMES MORE DIFFICULT.
Abiotic factors important in habitat creation
Water availability, salinity, temperature, pH, light levels, minerals and nutrients, dissolved O2.
Biotic factors important in habitat creation
Food, pollination, seed dispersal, re-introduced species, succession control, predator control, competition control, pathogen control.
Re-introducing species
humans have changed many habitats, but most CAN be rewilded. Rewilding is when a habitat, which has been altered but retains many original features, is restored by re-creating more natural conditions. Many species will colonise these habitats naturally, while less mobile species will need to be reintroduced.
PARTICULARLY IMPORTANT TO REINTRODUCE KEYSTONE SPECIES.
Wolves reintroduced to Yellowstone National Park
Without wolves, elk population exploded, leading to overgrazing and damage to vegetation, which affected other species like beavers. The reintroduction of wolves helped restore balance to the ecosystem by preying on elk, allowing vegetation to recover, which benefited other species.
PRESENCE OF WOLVES ALSO ALTERED ELK BEHAVIOUR, PREVENTING THEM FROM OVER FRAZING SPECIFIC AREAS.
Re- wilding in Scotland
Historically, was covered in forest, with a diverse range of species within it. However, deforestation, overgrazing, and climate change has led the natural landscape to disappear, resulting in a loss of biodiversity. Attempts are being made to restore this habitat, with baby scots pines recolonizing bare landscapes, encouraging some species to reclaim areas.
SPECIES ARE ALSO BEING REINTRODUCED, PROVIDING NATURE WITH TOOLS TO THRIVE
ECOLOGICAL SUCCESSION
If left completely untouched by humans, a habitat will evolve to its climax community THIS is the natural habitat for the location AND the process of colonization of such an area is called ecological succession.
What factors dictate thr natural climax community of an area?
ABIOTIC- daylight, soil, precipitation, wind.
BIOTIC- flora & fauna
Controlling ecological succession
A ‘plagioclimax’ is an ecosystem that has been prevented from developing into a natural climax community due to human or other external factors.
What human activities create plagioclimaxes?
deforestation, farming, hunting, trampling, mowing/grazing
Why not let all plagioclimaxes return to natural succession?
Some communities were formed many years ago, meaning some species have evolved or become specialised specifically to suit this plagioclimax AND are of great conservation value.
We also need some of this land for farmland, meadows, coppiced woodland.
