The introduced Mediterranean snails are the reason why the ‘ecosystem is way out of balance.’ They are weed-like in the rapid rate they can reproduce, plus they lay their eggs in the soil and the young do not all emerge together so they can be knocked off in one go. Some seem to take several years to emerge, thus making control over large areas almost impossible. Like most snails they enjoy eating young herbaceous vegetation during the cool moist periods of winter/spring, but then climb off the ground to escape the very hot summer temperatures at ground level, hence the great clusters of snails on those fence posts. These clusters cause problems as they can interfere with feeding stock and will clog up farm machinery. In some unmanaged paddocks, the snails (thick on remnant vegetation and weeds) can be seen as far as the eye can see. No wonder some people refer to this country as ‘heart-break country.’ Near where I live, there are calcareous tertiary dunes where these Mediterranean snails occur, these dunes end abruptly and acid sandy soils (heathland) begin. Interestingly, the snails are common right up to the acid sand boundary then stop and despite spending a fair amount of time looking, I have not found them over this line. I would think one of the reasons why these snails are not interested in exploring the acid soils is because there is no calcium there to make their shells, whereas in the alkaline soils, limestone is part of the environment.