Management of forest fire buffer zones: Implications for flowering plants and bees

Abstract

Pollination, especially by bees, has high importance for man and nature. Ongoing global declines in bee populations make their present and future conservation crucial. We investigated how management of natural areas affects plants and pollinators, in the context of fire prevention measures in Mediterranean forests. The standard forestry practice to reduce fire hazard includes construction of vegetation-thinned buffer zones near roads and human settlements. Such buffer zones are commonly maintained by livestock grazing or mechanical trimming to prevent forest regrowth. We conducted a controlled and replicated field experiment to assess the effects of these maintenance practices on flowering plants and bees. Vegetation was thinned in 32 experimental plots at the Mt. Carmel Nature Reserve, Israel, to simulate construction of fire buffer zones. Sixteen plots were either grazed by sheep or trimmed during the following year, while the remaining plots received no maintenance treatment. We surveyed the flowers (identified to species) and bees (identified to genus) in the plots over three years: before, during and after the maintenance interventions. Maintenance management (regardless whether by grazing or by trimming) affected the floral community composition, as did monitoring date and the plots' fire history (burnt either four or >20 years earlier). However, the abundance and diversity of flowers and bees, and the bees' community composition, did not differ between plots that received maintenance treatments and their paired non-maintenance controls. We conclude that many aspects of flower and bee assemblages in the reserve are little affected, in the short term, by the maintenance practices of fire buffer zones. As our experiment was limited to a one-year grazing/trimming intervention, future studies should assess the longer-term effects of these management activities on pollination interactions.