Boucher Philippe, Hébert Christian, Francoeur André, Sirois Luc
Département de Biologie, Chimie & Géographie, Université du Québec à Rimouski, 300 allée des Ursulines, Rimouski, QC, Canada G5L 3A1.
Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, 1055 du P.E.P.S., P.O. Box 10380, Stn. Sainte-Foy, Québec, QC, Canada G1V 4C7.
Environ Entomol. 2015 Oct;44(5):1316-27. doi: 10.1093/ee/nvv109. Epub 2015 Jul 14.
Dead wood decomposition begins immediately after tree death and involves a large array of invertebrates. Ecological successions are still poorly known for saproxylic organisms, particularly in boreal forests. We investigated the use of dead wood as nesting sites for ants along a 60-yr postfire chronosequence in northeastern coniferous forests. We sampled a total of 1,625 pieces of dead wood, in which 263 ant nests were found. Overall, ant abundance increased during the first 30 yr after wildfire, and then declined. Leptothorax cf. canadensis Provancher, the most abundant species in our study, was absent during the first 2 yr postfire, but increased steadily until 30 yr after fire, whereas Myrmica alaskensis Wheeler, second in abundance, was found at all stages of succession in the chronosequence. Six other species were less frequently found, among which Camponotus herculeanus (Linné), Formica neorufibarbis Emery, and Formica aserva Forel were locally abundant, but more scarcely distributed. Dead wood lying on the ground and showing numerous woodborer holes had a higher probability of being colonized by ants. The C:N ratio was lower for dead wood colonized by ants than for noncolonized dead wood, showing that the continuous occupation of dead wood by ants influences the carbon and nitrogen dynamics of dead wood after wildfire in northern boreal forests.
枯木分解在树木死亡后立即开始，涉及大量无脊椎动物。对于依赖枯木生存的生物，尤其是在北方森林中，其生态演替仍鲜为人知。我们沿着东北针叶林60年的火灾后时间序列，研究了枯木作为蚂蚁筑巢地点的利用情况。我们总共采样了1625块枯木，其中发现了263个蚁巢。总体而言，蚂蚁数量在野火后的前30年增加，然后下降。在我们的研究中最丰富的物种——近似加拿大细胸蚁（Leptothorax cf. canadensis Provancher），在火灾后的前两年不存在，但稳步增加直到火灾后30年，而数量上排名第二的阿拉斯加蚁（Myrmica alaskensis Wheeler），在时间序列演替的所有阶段都有发现。其他六个物种较少被发现，其中巨木工蚁（Camponotus herculeanus (Linné)）、近红褐蚁（Formica neorufibarbis Emery）和阿氏蚁（Formica aserva Forel）在局部地区数量丰富，但分布较稀少。躺在地上且有许多蛀虫洞的枯木被蚂蚁定居的可能性更高。被蚂蚁定居枯木的碳氮比低于未被定居的枯木，这表明蚂蚁对枯木的持续占据影响了北方寒温带森林野火后枯木的碳氮动态。
