L5 - Marine Biodiversity
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How has the way we view biodiversity changed?
It previously just looked at the number of species in a community at a fixed time and place. Now we also considered evenness and dominance
What is Ecological Diversity?
Variations of ecosystems and assemblages
Give an example of a community
Macroalgae on a rocky shore
What is an assemblage?
Species that have a common ancestor
What is an ensemble?
Phylogenetic: species that are related and use the same resources within an ecosystem
Give 7 reasons why biodiversity is important
• Species Richness • Survival Rates • Food Web Stability • Food Web Balance • Conservation Quality • Resource Quality • Legislation
Give 6 pieces of legislation behind the use of biodiversity
• Wildlife and Countryside Act (1981) • Convention of Biodiversity • Jakarta Mandate on Marine and Coastal Biodiversity • Biodiversity Action Plans (UKBAPs and LBAPs) • Eu Habitats Directive (1992) • Water Framework Directive & The Water Bill
What is evenness?
How similar species abundances are
What is dominance?
The extent to which one species is most abundant
Rarity is a function of what 3 things as said by who?
• Geographic Distribution • Habitat Specificity • Local Population Size (Rabinowitz et al., 1986)
Give 3 ways of looking at commonness and rarity
• K-Dominace • Rank Abundance Plot • Absolute and Relative Rarity
What are the 4 species concepts?
• Biological Species Concept (reproductively isolated) • Cohesion Species Concept (isolated geographically but maybe not biologically) • Ecological Species Concept (set of organisms adapted to a single niche) • Phylogenetic Species Concept (we don’t really know!)
What is Cryptic Biodiversity?
Species that look the same and behave the same but have different genetic make ups
What 2 types of evolution need to be considered?
• Isolated 2. On-Going
Give 6 methods of assessing species richness?
• Species Accumulation Curves • Rarefaction • Smax • Chao 1 and 2 Models • Remote Sensing • Diversity Indices (Margalefs, Menhinicks,Shannons and Simpsons)
What impacts species richness?
Survey Effort, Temporal and Spatial variations and Open or Closed System
What is a cryptic species?
Hard to see and therefore under recorded
Give 4 types of species surrogate measurements
• Cross-Taxon • Within-Taxon • Environmental • Body Size
How many species are un-recorded?
~3-8million
When should Simpsons and Shannons be used?
Simpsons 25 spp.
For diversity what does 0 and 1 mean?
0 - no diversity 1 - infinite diversity
What value represents a diverse habitat?
0.7-0.8
What is alpha diversity?
Spatial diversity
What is beta diversity?
Diversity due to changes in species (spatial or temporal change): species gain/loss also known as turnover diversity