Lecture 2 - sampling biodiversity

Question 1

what are problems with sampling biodiversity in tropical forests?

Answer 1

• difficult to see
• difficult to hear (rivers etc)
• so many species which are difficult to identify
• problem of over-counting individuals
• distance to individual is to estimate

Question 2

describe a point count study

Answer 2

• used to sample at lest 2 widely spaced sample landscapes
• each point count should be fair enough apart they are independent
• need to make sure effective sample zone samples unique community
• can use pitfall traps, butterfly traps

Question 3

2 things to think about when designing a point count study

Answer 3

• do count early in the day for birds and mammals

- change order that you visit a set of counts

Question 4

how do you analyse point count data?

Answer 4

• draw species accumulation curves with shared data
• cumulative number of species on y axis
• cumulative number of individuals on x axis
• if curve reaches an asymphote then it was sampled effectively

Question 5

what are the positives of species richness?

Answer 5

• shows that you have sampled effectively when ur accumulation curve levels off
• good at showing big differences in number of species between groups of habitats

Question 6

what are the negatives of species richness?

Answer 6

• doesnt show how abundance changes within species
• doesnt show whether species present are same or different e.g. 10 species vs 10 different species
• total species richness is misleading if sampling effort is not equal between groups e.g. more species because sampled more
• use in conjunction with species composition