Here is a map of my 1km square here in Guernsey. We do not really use the national grid-square system of the UK, so I have decided that it will be easier to use a square centred on my house, St. Etienne.
The local area is distinctly suburban, with the main habitat being gardens, in which of course I will not be able to search. The local industry is horticulture so there are many glasshouses growing tomatoes and flowers. In between these, there are many small fields of grass - some kept short by cows and others left to grow for silage. A few of these are almost 'meadows' at times. There are no areas of open water apart from an inaccessible flooded quarry which I can just peer over a wall into. There are however numerous ditches, known as douits, along which water plants do grow. There are one or two scrubby areas and abandoned fields which may be important to search. There is no woodland but along the borders of fields and in the gardens there are a lot of mature trees. The area is flat and very low-lying (even below sea-level in the far NE). Walking the lanes in Guernsey are usually very productive as they are generally bordered by quite vegetated banks. The uniformity of the area may restrict my total, but I am sure that I can get a few species that do not occur in the UK for major grippage (to use birding parlance).