UA cloudflare authentication

Browsing by Author "Kleinman, Jonathan Samuel"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Catastrophic wind and salvage harvesting effects on woodland communities
    (University of Alabama Libraries, 2017) Kleinman, Jonathan Samuel; Hart, Justin L.; University of Alabama Tuscaloosa
    Compound disturbances may result in novel forest successional and developmental patterns. This study investigated effects of post-wind disturbance salvage harvesting, a unique compound disturbance of which the ecological consequences are unresolved, in fire-restored longleaf pine woodlands of the Alabama Fall Line Hills, a characteristically biodiverse and rare ecosystem. Floristic inventories were developed and plot-level data were collected in areas undisturbed, wind-disturbed, and compound-disturbed (wind + salvage) to compare disturbance-mediated differences in (1) physical site conditions, (2) woody plant composition and structure, and (3) ground vegetation (herbaceous and woody plants ≤ 1 m in height). Multivariate analyses revealed distinct differences in ground vegetation across disturbance categories. Biophysical drivers most correlated with differences in species assemblages included volume of coarse woody debris, sapling density, percent canopy cover, and basal area. Wind-disturbed plots had the greatest species richness and diversity of saplings and ground vegetation, and had indicator species with unique habitat requirements (specialists). Indicator species of compound-disturbed plots were mostly generalists with broad habitat requirements. Reduced species diversity on compound-disturbed plots was attributed to salvage harvest-mediated reductions in habitat heterogeneity. Thus, leaving patches unharvested within salvaged stands is recommended to promote stand-scale plant diversity. Interestingly, regeneration of longleaf pine, the most desirable species in the system, increased with collective disturbance severity. Nonetheless, longleaf pine saplings and seedlings were markedly outnumbered by other species in all disturbance categories, indicating that these woodlands need prescribed fire or other competition reduction measures for recovery toward longleaf pine dominance.
  • Thumbnail Image
    Item
    A review and case study of multiple interacting disturbances in forest ecosystems
    (University of Alabama Libraries, 2021) Kleinman, Jonathan Samuel; Hart, Justin L.; University of Alabama Tuscaloosa
    Strategies to enhance ecosystem resilience are increasingly needed in forest management plans. Natural and managed disturbances that alter ecosystem resilience to other perturbations are called compound disturbances. This dissertation first synthesized the literature on compound disturbances in forest ecosystems. I used a systematic review to catalogue case studies of compound forest disturbances and identify trends in the types, timing, environmental settings, and ecological consequences of each disturbance combination. The review emphasized that the detection of positive, negative, and neutral disturbance impacts on ecosystem resilience were often contingent on which response variables were used to monitor forest recovery. To illustrate and investigate this and other key concepts described in the review, I then examined a combination of wind disturbance, salvage logging, and prescribed fire in the Alabama Fall Line Hills. A range of woody plant, ground flora, and ground surface material metrics were collected before and after prescribed fire in Pinus palustris Mill. woodlands differentially impacted by an EF3 tornado and salvage logging. In support of the review, salvage logging and prescribed fire had different effects on post-wind disturbance recovery depending on which response variables were assessed. Pinus palustris saplings exhibited the greatest densities in salvage-logged sites and were more resistant to prescribed fire than most other sapling species. This indicated that recovery toward P. palustris canopy dominance was not negatively affected by salvage logging and was enhanced by prescribed fire. Ground flora diversity and community dissimilarity, however, were reduced in salvage-logged sites before and after prescribed fire. Nonetheless, prescribed fire did impose some consistent selective pressures on understory plants with common life-history strategies. Overall, this dissertation supported the use of prescribed fire to promote P. palustris woodland recovery. Leaving some wind-disturbed zones unlogged was also recommended to support ground flora resilience. Moving forward, a diversity of response variables should be measured to achieve comprehensive assessments of disturbance effects on ecosystem resilience.