DEFORESTATION & CONSERVATION Flashcards
Deforestation
Creates CO2 as trees absorb CO2 which is released when burnt
Reduces diversity due to loss of habitats, niches, ecosystems, food, soil erosion and by changing the climate
Causes soil erosion as there are no trees to protect soil from rain
Causes changed rainfall patterns and droughts as there is less transpiration from leaves
How deforestation increases CO2 concentration
Less trees means less photosynthesis
Less photosynthesis means less CO2 absorbed from the atmosphere
Burning of the trees involves combustion which produces CO2
Reasons for conservation of the forest ecosystem
Trees available as a sustainable resource
Maintain habitats
Maintain diversity and protect endangered species
Maintain stability of ecosystem
Maintain food chains
Reduced loss of soil
Reduced flood
Reduce greenhouse effect and therefore global warming
The forest ecosystem is also a source for medicines
Succession
Change in a community over time due to change in environment
CONSERVATION OF HABITATS FREQUENTLY INVOLVES MANAGEMENT OF SUCCESSION
Two types of succession
Primary Succession: starts with bare rock usually after a volcanic eruption
Secondary Succession: starts with soil usually after a forest clearing
How Succession occurs
Colonisation by pioneer species
As pioneer species increase in number, they die and are broken down by saprobionts which increase humus content
Change in environment as there is an increase in organic matter and nutrients, the humus helps maintain moisture
This enables other species to colonise
This causes a change in biodiversity
The environment becomes less hostile
New species better competitors and eventually one species outcompetes other species
This species is called the climax community
Why pioneer plants having seeds that grow in fluctuating temperatures is an advantage
At the start of succession, there is only bare soil
Temperature in bare soil always fluctuates
Climax Community
Stable community after which no more succession takes place
Trees that are usually the tallest and bulkiest will be the best as they will block light, needed by other plants for photosynthesis, therefore the climax community usually reduces plant diversity as those plants survive which can photosynthesise with less light
Why nitrate in the soil increases during succession
Increase in dead organisms
Leading to an increase in nitrification
Also nitrogen-fixation could also be taking place making ammonia, which then turns into nitrate
Sometimes, the plant/forest is burnt, and succession begins on the burnt land, this is beneficial because
Younger plants have more shoots, therefore provide more food
Younger plants provide more cover
Unproductive plants are removed
Why diversity of animals increases
Greater variety of food
Higher variety of habitats
More detritus
In sand-dune ecosystem, minerals enter the ecosystem by
Flooding by seawater Weathering of underlying rock Nitrogen fixation Excretory products In a sand dune system, the climax community will be the furthest away from the sea and the pioneer species will be widespread.
