Oak savanna management strategies and their differential effects on vegetative structure, understory light, and flowering forbs

摘要: High quality oak savanna communities were once abundant in the North American Midwest, but have become exceedingly rare. Where remnant savannas remain, fire suppression and resulting woody encroachment dramatically altered vegetative structure, reduced understory light levels precipitating declines herbaceous diversity. Restoration of suppressed generally involves reintroduction fire, questions remain regarding necessity impact mechanical vegetation reduction addition to fire. We report here on initial short-term results a long-term experiment fire-suppressed Southern Michigan compare gradient management intensities including; (1) unmanaged reference plots, (2) burning alone (low intensity), (3) progressive thinning combined with (high intensity). measured several metrics restoration success: understory, shrub, canopy cover, levels, floral resources, flowering forb diversity, first two growing seasons after initiation treatments. found that increasing intensity largely corresponded increased availability, abundance resources (i.e. bloom diversity), decreased shrub cover. Low did not increase or decrease cover relative references, while high achieved both goals. Both + diversity forbs, where effect was greatest management. These increases most pronounced second season burning, when we saw sharp richness forbs. In restored community consisted pre-existing shade tolerant species, native exotic ruderals, as well indicator species. sum, low-intensity can achieve some objectives over short-term; however, show clear advantage coupling alone. suggest these differing may be appropriate under different temporal, financial, ecological scenarios. Our work highlights potential for by low approaches, relict populations and/or viable seedbanks exist.