Over the last century, land use in the UK has changed drastically. Small mixed-crop farms, traditionally separated by lanes, hedgerows and wild meadows have been replaced with larger, more specialised facilities. At the same time, the density of grazing animals such as sheep and cattle has also risen substantially. This combination of land-use change and agricultural intensification has contributed significantly to habitat degradation and biodiversity loss, and has led to huge, often dire, changes for the wildlife that call these places home.
Understanding these processes is of huge importance to conservationists, and a considerable amount of research has been conducted into the broad scale effects of land use changes on biodiversity. It is less well understood, however, why seemingly similar species can be affected to a different extent by local changes in their habitat.
A recent study, conducted by Dr Andrew Higginson at the University of Exeter, suggests that competition for nesting space may be a key factor in the differences observed. His study used a mathematical model to predict the likely outcome when populations of birds and bees are faced with a reduction in suitable nesting sites. Results indicated that larger, earlier-nesting species tend to fare better in these conditions, but at the expense of smaller, later-nesting species who, in the real world, would either fail to find a nesting site or be forced into using a poor quality or risky location.
Dr Higginson’s results illustrate that, whilst two or more similar species can co-exist together very happily when there are sufficient nesting spaces available, as soon as these become limited, competition and conflict become inevitable. In severe situations, species that have historically thrived in the same environment may suddenly find themselves battling for survival.
A key message from the study was that conservation efforts should ensure that priority is given to the creation and maintenance of suitable nesting sites. Conservation practices often focus on provision of food for wildlife, such as planting wildflowers for bees and providing food for our garden birds. Preserving and creating safe and accessible places for these animals to nest, however, is just as critical if we are to ensure their continued survival.