Please enable JavaScript.
Coggle requires JavaScript to display documents.
3.1. INTRODUCTION TO BIODIVERSITY (Knowledge and Understanding…
3.1. INTRODUCTION TO BIODIVERSITY
Knowledge and Understanding
Biodiveristy can be identified in a variety of forms including species diversity, habitat diversity and genetic diversity
Species diversity
in communities is a product of two variables - richness (number of species) and evenness (relative proportions)
Habitat diversity
- refers to range of different habitats in an ecosystem or biome
Genetic diversity
- range of genetic material present in a population of a species
Biodiversity as an indication of ecosystem health
high biodiversity usually equates with high ecosystem health
Advantages of a habitat with high biodiversity
resilience and stability due to the range of plants present - of which some will survive floods, drought, insect attack, disease etc
genetic diversity therefore resistance to diseases
some plants will have deep roots so can cycle nutrients bringing them back to the surface making them available for other plants
High biodiversity does not always equate having a healthy ecosystem
diversity could be the result of fragmentation (break up) of a habitat or degradation when species richness is due to pioneer species invading bare areas quickly
managing grazing can be difficult as plant species have different requirements and tolerance to grazing
some stable and healthy communities have few plant species so are an exception to the rule
Diversity indices
it is only possible to accurately compare two similar ecosystems or two communities within an ecosystem
when comparing similar communities - low diversity could be evidence of pollution, eutrophication or recent colonisation of a site
Investigations should be repeated over a period of time within the same community - makes it easier to identify if changes are occuring from human causes or a natural process due to succession
Hotspots
many hotspots include endemic species (only found in that place)
they tend to be nearer to the equator - less limiting factors in lower latitudes
they are all threatened areas where 70% of the habitat has already been lost
cover only 2.3% of the land surface