- Santillo, David J.
University of Maine Graduate School
The effects of herbicide-induced habitat changes on small mammals and songbirds were investigated in north-central Maine during 1985-86. Changes in small mammal and songbird populations were compared to differences in vegetation on untreated and herbicide-treated clearcuts, 1 to 3 yrs after application of herbicides for conifer release. Six study sites were selected sites: 2 each of untreated controls, before to 1 yr post-treatment, and 2 to 3 yrs post-treatment.
Small mammals were trapped on each study clearcut by snap and pit-trapping on 8 x 8 station grids spaced at 15m intervals. fewer small mammals were captured on herbicide-treated clear cuts than on untreated clear cuts for all 3 yrs post treatment. Insectivores (Soricidae) accounted for 72% of all small mammals captured, and were less abundant (p < 0.001) on 1 to 3 yr post treatment sites. Herbivore-granivores (Microtinae) were less abundant on 1 (p < 0.01) and 2 yr (p < 0.001) post-treatment sites. Omnivores (Cricetinae, Zapodidae) were equally abundant on treated and untreated clearcuts. Differences in small mammal populations were explained by a reduction of invertebrate and plant food on herbicide-treated sites, and the herbicide-induced reduction in cover.