The role of the understory on the abundance, movement and survival of Ceroglossus chilensis in pine plantations: an experimental test

Abstract

Tree plantations may play a role in the conservation of global forest biodiversity. At the landscape scale, plantations with a complex understory may provide surrogate habitats for forest-dwelling organisms. This was tested using a manipulative experiment in which the abundance, movement and survivorship of Ceroglossus chilensis (an endemic and flightless ground beetle) was examined in plantation forest stands where the density of the understory vegetation was manipulated. Between 2009 and 2012, we collected C. chilensis by pitfall trapping in nineteen plots with naturally high, naturally low and experimentally removed understory cover. Beetle movement was evaluated by direct observation, and survival was quantified as the proportion of days that individuals survived in closed and open containers half-buried in the soil. C. chilensis exhibited higher abundance in plots with naturally high than with low or experimentally removed understory cover. Beetles traveled shorter distances and preferred to stay in stands with developed understory. C. chilensis had significantly higher mortality by predators in plantations with scarce understory cover. Therefore, forest plantations with a dense understory can become surrogate habitats for C. chilensis, and may contribute to the conservation of its populations.