On the very smallest scale, biodiversity refers to the variability of the genetic makeup of different species and individuals.
Assessing biodiversity, i.e. evaluating the amount or quality of natural diversity is difficult because the concept refers to all of the above, and any single figure can only depict one factor. It is not possible to provide a single value or figure as a measure for biodiversity.
Diversity varies according to the developmental stage of forests
Participants in forest-related debate sometimes voice the concern that biodiversity will decrease if forests are logged. The opposite claim is that biodiversity increases with logging – which is not as fanciful as it may at first appear. Logging leads to a decrease in the occurrence of species that thrive in closed forests in particular. Species, which do well in the open, proliferate rapidly in regeneration areas, however. If only the number of different species is examined, biodiversity may have increased in a harvested area over a few years. The species are, however, quite different compared to the pre-logging situation because both forest species and those preferring open habitats are present. Their relative numbers will also have changed substantially.
Conservation areas safeguard threatened species
The natural diversity of the forest environment is safeguarded through, for example, the establishment of nature conservation areas and by taking biodiversity into consideration in the planning of forestry measures. Nine percent of Finnish forests are under strict conservation, which means that no timber harvesting whatsoever is permitted there.
Newcomers challenging native species
In nature, diversity is always in flux. Roe deer, lynx and the eagle-owl are species that have become more and more common in Finland over the last few decades. Now, as the climate is warming, some new butterfly species, insects and fungi have also been spotted in Finland. As average temperatures rise, forest damage may also become more common and occur in different ways. Species will have to adapt to changes in their habitats and also compete with new species that are encroaching into their areas. Warty comb jelly, fishhook waterflea, large-leaved lupine, Canada goose, raccoon dog, mink and so-called city rabbits are examples of alien species that have spread into Finland. Original species often do not compete well against new arrivals that are better adapted to the changed conditions of their habitat.
Suvi Raivio, Senior Advisor, Biodiversity,
Finnish forest Industries Federation, +358 9 132 6671
The UN has declared 2010 as the International Year of Biodiversity. For the remainder of 2009, this series of articles will examine concepts and phenomena that are related to biodiversity.