关键词: 白尾鹿, 食草作用, 土壤酸化, 生态指示物种, 石灰, 除草剂, 土壤化学

Abstract: In eastern North America, cucumber-root (Medeola virginiana) is a widely distributed perennial forest herb that has been used as an ecological indicator of white-tailed deer (Odocoileus virginiana) browsing due to its predictable responses to deer exclusion (i.e., increased height, abundance). However, cucumber-root is less likely to occupy sites with high concentrations of soil manganese (Mn), which may limit its utility as an indicator under limiting soil conditions. We examined responses of cucumber-root total counts and flowering abundance to deer exclusion, competitive release from surrounding vegetation, and soil application of dolomitic limestone to determine the relative effects of these treatments over 7 years (2014–2021). Prior to treatment, initial total and flowering abundance were best explained by soil extractable Mn concentration. Post-treatment, fencing best explained increases in total counts, but flowering abundance was most affected by soil extractable Mn and pH. Initial soil Mn concentrations determined the effectiveness of dolomitic limestone application; microplots with moderate to high soil Mn (> 6 cmol_c kg^–1) had increased flowering with increased pH, while flowering decreased on microplots with initially low soil Mn concentrations (< 6 cmol_c kg^–1). We suspect changes to soil chemistry from liming affected plant stress, but that stress was either alleviated or intensified depending on initial soil Mn concentrations. Herbivory is an important driver of plant abundance across our study area but flowering response, a critical component of plant demography, seems to be driven by soil Mn. Cucumber-root may have limited utility as an indicator because soil chemistry mediates flowering responses to deer exclusion.

Key words: white-tailed deer, herbivory, soil acidification, ecological indicator, lime, herbicide, soil chemistry