C.4: Conservation of biodiversity

BIODIVERSITY Defined as the variety of life! Biodiversity is essential to the health of ecosystems. Biodiversity within an ecosystem can change over time, often as a result of human activity. http://ngm.nationalgeographic.com/2011/01/seven-billion/biodiversity-game How could you assess biodiversity?

Indicator species & biotic index Indicator species is an organism used to assess a specific environmental condition. E.g. Fruticose lichens are very sensitive to air pollution, therefore if they disappear from an ecosystem it is likely to indicate a change in air quality. Biotic index compares the relative frequency of indicator species.

Benthic macroinvertebrates These are bottom dwelling invertebrates found in rivers. They give a good indication of the health of of a stream, because: They live in the water during the aquatic developmental stage of their life cycle Easy to capture Vary in their response to chemical and physical changes to the habitat Open the document C.4 Guide to benthic macroinvertebrates Go to this web page: http://www.dep.wv.gov/WWE/getinvolved/sos/Pages/MacroID.aspx Try and identify 5 invertebrates DO NOT EMAIL THE COORDINATOR How could you use this technique in the field?

In situ V’s Ex situ conservation Endangered organisms remaining in their natural habitat Aim of preserving the natural niche for the organism e.g. nature reserves Control grazing, remove some shrubs/trees, remove alien/cull invasive species, reintroduce species, limiting predators, feeding animals etc. Preservation of endangered organisms outside of their natural habitat. Used as a back up to in situ conservation. e.g. botanical gardens Captive breeding programs

Richness V’s Evenness In a biological sample, ecologists would judge: Richness = number of different species present Evenness = How close in numbers each species is Number of individuals Flower species Sample A Sample B Daisy 300 20 Dandelion 335 49 Buttercup 365 931 Total 1000 Both samples have the same richness, but A is more even. Therefore A is considered more diverse than B. As species richness and evenness increase so does diversity. Simpsons diversity index is a measure of diversity which takes into account both richness and evenness.

Simpson’s diversity index Used to analyze the biodiversity of two communities. Takes into account both richness and evenness using this formula.

caution With the Simpson’s index, 0 represents infinite diversity and 1, no diversity. The bigger the value of D, the lower the diversity. This is not logical! So, ecologists will often do one of two things: Simpsons index of diversity 1 – D By subtracting D from 1, the greater the value the greater the diversity. This makes more sense. In this case the index represents the probability that two individuals randomly selected form a sample will belong to different species. Simpson’s reciprocal index 1 / D Here the lowest possible figure is 1, which would represent a community containing only one species. The higher the value, the greater the diversity. The maximum value is the number of species in the sample.

Example D = 0.3 Simpson’s index of diversity = 0.7 This data was collected from a single quadrat sample of ground vegetation in a woodland. Is this data reliable? Why/why not? Species Number (n) n(n-1) Woodrush 2 Holly (seedlings) 8 56 Bramble 1 Yorkshire Fog Sedge 3 6 Total (N) 15 64 The Simpson’s index gives more weight to the more abundant species in a sample. The addition of are species causes only small changes in the value of D. D = 0.3 Simpson’s index of diversity = 0.7 Simpson’s reciprocal index = 3.3

Example 2: Groups of students studied the species diversity of the beetle fauna found on two upland sites in Europe. The same number of students searched for a similar length of time in each of the two sites. The two sites were of equal area. The number of individuals of the four species found at each site is given in the table below. Calculate the Simpson’s reciprocal index for the beetle fauna on each site. Suggest a conclusion regarding a comparison of biodiversity between the two sites. Species Site a Site b Trichius fasiatus 10 20 Aphodius lapponum 5 Cicindela campestris 15 8 Stenus geniculatus 2

Influence of biogeography Biogeography encompasses the idea that the area of land making up the ecosystem has a significant impact on the biodiversity of the area. e.g. a large nature reserve, or several small nature reserves connected together are able to support a higher biodiversity of organisms. The ecology at the edge of ecosystems is different to that of the central area so the shape of the ecosystem or nature reserve is important. Circular areas of land are much better. https://www.youtube.com/watch?v=D2buIXiz1sk