The primary factor that governs most ecology is the soil. The soil on Hartslock is very nutrient poor – in fact there is virtually no soil at all to cover the underlying chalk in some places. This works to keep the stronger growing, commoner plants down so that plants like Nettles and rank grasses cannot survive. When these natural success stories are kept at bay it allows some of natures specialists to move in.
Many rare plants have adapted to eking out an existence in poor soils but to do this they often have to develop special strategies to overcome some of the difficulties. Many are dwarf or very slow growing – conserving their meagre resources.
Because Hartslock is very small it cannot support independent colonies of the larger animals and it has never been a particularly good site for bird watching. However, it is very important for invertebrates (‘creepy-crawlies’ for want of a better word), which usually require smaller habitats and exist in much smaller ecosystems. The special ones on Hartslock occur in very few other sites in the area so, for them, Hartslock is an oasis in a desert of inhospitable countryside. These invertebrates tend to be on Hartslock because it has the only colony of the foodplant they eat or because it has the only suitable place to lay eggs or look for a mate.
It is important to remember that, in all ecosystems, the species are inter-linked and many cannot exist without the presence of others.