Biology - Help with data analysis

[sjtnz]

Hi, I'm a bit lost in the dark.... I am doing a study at University but am rusty on statistics. I am trying to interpret some data I collected on a fieldtrip. I am trying to prove that abotic factors effect insect abundance differently in different forest types. Samples of overall abundance were collected 4 hourly for 48hrs - in 2 different forests. Abotic factors such as rainfall, temperature, day/night ect. measurements were taken at the same time. The problem I am having is that in one type of forest there was a higher abundance in general, so I can't directly compare the two forests in varying abiotic conditions.

For example: At X temp there were 55 insects in T forest and 58 in N but their overall means are T =34 and N =55 or....when temp was 12C there were 52 in T and 61 in N, when temp was 15C there were 60 in T and 64 in N, 20C 70 in T and 66 in N.

To try and clarify myself, I would like to see if in one forest there are proportionately more (without the distraction of the fact that one forest has way more anyway) insects when it is raining, or temp rises.

I'm not really sure how to start to prove with statistics/put on graph. I think I would somehow like to have a graph with abundance on X axis and Temp on Y. But if I plot them straight on then I get one forest type just showing a great deal more anyway. Is there some way of isolating/getting rid of that bias? Possibly so I can have one line on said graph showing as temp rises, insect abundance increases proportionately more in T forest?

Well done getting to the end of this long-winded wander, I hope that has made some sense. Thanks for any help,


Steve

[bugman]

Excuse the rushed response, but Im in a hurry. A few things to consider:

1) why do you need to standarsdise these? Biologicaly, the interaction between forest type and temperture would be more useful, which can be used using a one way ancova with temp as your covariate.

2) If you HAVE to account for the difference in forest type, then I would suggest looking at the relative change in abundance at different temps. between forest types.

Phil