De effecten van een heidebrand op de adderpopulatie

The effects of fire on a local adder population On March the 13th (2015) a 100 acres of heather vegetation burned down in the Fochteloërveen area (a large peat moor). A survey was conducted to get an impression of the effects of the fire on the local adder population (Vipera berus). A series of hibernacula within a charred area were monitored over a three year period by means of species specificcapture-mark-recapture methods in order to determine movements of individuals. During the field surveys no dead or injured adders were found, which is probably the result of bad weather conditions on the day the fire took place. Twelve male adders were observed during or shortly after leaving their hibernacula in the charred area. Instead of initially staying in the vicinity of their hibernacula they soon moved to unaffected parts of the Fochteloërveen. Only three adders were found leaving the same hibernacula in 2016 and only one in 2017. The hibernacula seem to have become less functional because of the abundance of purple moor grass (Molinia caerulea) which has a negative impact on the presence of basking spots in the vicinity of the hibernacula. In conclusion: the fire seemed to have a more pronounced long term effect rather than a short term effect on this adder population. The future will tell if the affected parts of the Fochteloërveen will become more suitable for hibernation as the purple moor grass vegetation ages and gains structure. Op 13 maart 2015 vond in het Fochteloërveen een grote brand plaats, waarbij ongeveer honderd hectare aan heidevegetatie in vlammen opging (Nijhof & Bouma, 2015). De verbrande heide beslaat een groot deel van het onderzoeksgebied, waar reeds enkele jaren door de auteur onderzoek wordt gedaan naar de daar aanwezige adderpopulatie. Al snel rees de vraag wat voor effecten de brand zou hebben op deze populatie. In de literatuur bleek geen informatie voor handen te zijn waarmee deze vraag beantwoord kan worden. Hierop werd besloten om het populatieonderzoek in dit gebied deels op deze vraag toe te spitsen. Hierbij is de focus gelegd op zowel de korte- als de langetermijneffecten.