1
$\begingroup$

I study soil insects, and sample monthly for insects. Each month, I sample at 8 different sites. Each site is divided roughly into 4 meter square quadrants (shown in figure). From each quadrant, I pick out ~ 50 cm^2 of soil and look for insect samples (solid filled circles). I repeat this each month.

enter image description here

I do not have GPS points for each of the colored circle but I know that it belongs to different quadrant. Each ~ 50 cm^2 of soil is unique spatially and temporally.

Data-wise I have a grid that looks like this for each month.

                  site1.Q1    site1.Q2     site1.Q3     site1.Q4     site2.Q1   site2.Q2 ...
    species 1        0           5           10            2           40         5
    species 2       90           0            0            0           22         1
    species 3        7           0            0            2           89         90

I want to analyze: (a) Is there spatial aggregation within a site for each species? (b) What is the extent of spatial niche overlap between species? How does this change over time?

For (a) Would Lolyd's Mean Crowding Index is a good estimator of aggregation here? What other indices, or tests would be recommended?

For (b) If species species aggregate, then species may overlap in few of the 50 cm^2 soil samples. How can I test the extent of overlap? Some examples suggest Schoener's D but I'm not sure if that needs some abiotic variable like temperature/ moisture measurement.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.