In a previous post i mentioned the Flemish environmental policy is monitored by the MIRA-reports which make an inventary & evaluation of the policy.
For Nature, similarly, the Flemish Research Institute for Nature and Forest (INBO) publishes a two-yearly Natuurrapport (in Dutch) which gives an overview of biodiversity in Flanders, searches the causes of the changes detected and evaluates the actions taken. The report contains a chapter about climate change (pdf in Dutch only) as of course it is one of the factors changing ecosystems and thereby biodiversity.
One of the ways to evaluate the nature policy, is by using natuurindicatoren (English version on the same URL): of course it is impossible to measure every little parameter or species alive. Therefore, for each domain a set of parameters have been chosen that are considered to be indicative for the entire (sub)-domain. e.g. for the field of acifidication/overfertilisation => indicators are the concentrations of Phosphor, Nitrogen & the oxygen demand (both BOD & COD).
The graphic below shows the number of observations that have been made during the past 20 years of a number of Dragonfly-species that in Belgium are being considered to be 'Southern species', meaning they are/were considered to be non-indigeneous in Belgium. (Lestes barbarus seems to have a stable population since the middle of the 90ies)
In the domain of climate change, all indicators are :
- the spring arrival data of migratory birds (graph)
- the spring-index for dragonflies (graph)
- the appearance of Southern species of dragonflies (see image above and here)
- the peak moment of pollen-production in birch-trees (graph)
- a monitoring program for following-up the budding of several species of trees (still in it's testing phase)
When having a closer look at the flying-season of some indigeneous species of butterflies & dragonflies, there's no simple conclusion. Some species haven't changed their season, while for some others there are really significant changes :
In spring, the spring-index (first appearance) for Inachis Io (day peacock eye / dagpauwoog) is 42 days earlier than it was 20 years ago.
In autumn, the Plebeius agestis (Brown argus / bruin blauwtje) prolongued it's season no less than 62 days. Above this, this species in spring appears one month earlier, meaning it's yearly cycle nowadays is three months longer !
Regression analysis has shown there's a clear correlation between the flying season and temperature for 20 of the 23 monitored species of butterflies.
The INBO report Biodiversity indicators 2007 presents 22 Flemish biodiversity indicators according to the focal areas of the Convention on Biological Diversity and the EU biodiversity headline indicators, in order to track progress towards the achievement of the 2010 target.