Ecology Lab. Write up Instructions
On my web page are class data for plant volume, plant diversity and bird diversity
Write up
Calculate:
percent native vs non-native plants for each area.
The original question that you are to answer was "What is the effect of development on the local environment?"
You now have data with which to answer this question. Your answer, however, depends on exactly what you look at. Here are a series of questions you should consider.
1. How good is your data?? Consider absolute accuracy vs "comparative" accuracy (comparison of the two areas). Which is most important for this study?
2. From what you know about food chains or food webs, specialists vs generalists,
does the data make sense? (total numbers; how should plant volume relate to bird numbers?
3. How well do native bird species adapt to introduced plants? Which feeding types of birds adapt well and which do not? Do resident and wintering species differ in adaptability? Also remember – no bird eats grass
4. How you answer the overall question depends in part on whether you look at overall trends or at individual species. You should consider both aspects of the question.
5. Based on your findings, is there a realistic way to make development less destructive or more friendly to the local organisms? In answering this question, consider both what could be done and whether these changes are "acceptable."
Diversity Index
This is a way to compare the diversity of two areas. The scale takes into account the number of species and the number of individuals in a community. Species diversity indexes allow one to compare different communities
A community of 5 species and 100 individuals could have 20 of each species or could have 80 of one species and 5 of each of the remaining 4. The first would have high diversity and the second would have low diversity. Thus, the diversity index favors communities where there are several species each well represented rather than one species very common and the rest rare. A field of cotton would have a diversity index of 1. In general, diversity is good in plants as it leads to diverse organisms at higher categories.
the formula for diversity is D = N ( N-1)___
∑ n (n-1)
1 →∞
Where D = index of diversity
N = total number of individuals in all species
n = number of individuals in each species
∑ = means sum – the sum of data for each individual species
Examples
A) 100 individuals belonging to 5 species, 20 of each
100 (99) = 9900 = 5.21
20(19) + 20 (19) + 20 (19) + 20 (19) + 20 (19) 1900
B) 100 individuals belonging to 5 species, 80 of one species, 5 of each of the other 4.
100 (99)______= 9900 = 1.56
80 (79) + 5 (4) + 5 (4) + 5 (4) + 5 (4) 6356