Table 1 Ground surface data based on GPS measurements

1

Field locations

Specification of single locations of field allotments based on GPS readings of first point of entry of the cultivation area referred herein as field.

For estimating minimum distance between fields. This is an important parameter for estimating the probability of gene (pollen) transfer from genetically modified to conventional maize fields (or vice versa).

This is also useful to estimate the length of field borders.

2

Field sizes

Estimation of total acreage of fields - measurements taken at corners of the cultivation area ranging from 3-22 corners, depending on field extent.

Mean field size gives information on the dispersal characteristics of the cultivation area.

The spreading of pollen is more likely in regions with large number of smaller fields than in regions with fewer larger fields.

3

Feral/volunteer locations

Specification of precise location points within same habitat patch.

For estimation of nearest neighbour relations.

Assesses the probability of cross-pollination between fields and feral locations