Influence of repeated fertilization on forage production for native mammalian herbivores in young lodgepole pine forests

Forest Ecology and ManagementVolume 417, 15 May 2018, Pages 265-280 Influence of repeated fertilization on forage production for native mammalian herbivores in young lodgepole pine forests(Article) Lindgren, P.M.F.a, Sullivan, T.P.bEmail Author View Correspondence (jump link) aApplied Mammal Research Institute, 11010 Mitchell Ave., Summerland, British Columbia, Canada bDepartment of Forest and Conservation Sciences, Faculty of Forestry, University of British Columbia, 2424 Main Mall, Vancouver, British Columbia, Canada Abstract View references (97) Stand thinning and fertilization are silvicultural practices designed to enhance wood and biomass production. Applications of nitrogen-based fertilizers make nutrients potentially available to all trees, plants, and wildlife in a given forest ecosystem, and therefore may affect productivity of forage plants for native mammalian herbivores. Species associated with areas of forest fertilization in temperate and boreal zones of North America include mule deer (Odocoileus hemionus), elk (Cervus elaphus), moose (Alces alces), and woodland caribou (Rangifer tarandus), snowshoe hare (Lepus americanus), and several species of voles. Impacts of fertilization on forest plant species may have important consequences for the nutrition, cover, and consequent survival of these herbivores, particularly in winter. This study tested the hypothesis (H1) that large-scale repeated fertilization, up to 20 years after the onset of treatments, would enhance the biomass production of forage plants, particularly grass, forb, shrub and tree species for native mammalian herbivores. A secondary hypothesis (H2) predicted that mosses and terrestrial lichens would decline as part of the ground vegetation in fertilized stands. Study areas were located in lodgepole pine (Pinus contorta var. latifolia) stands near Summerland, Kelowna, and Williams Lake in south-central British Columbia, Canada. Each study area had eight replicate stands: four unfertilized, and four fertilized five times at 2-year intervals. Mean biomass of total grasses responded dramatically starting in the first year after fertilization. Total forbs and herbs also followed this pattern, although not to a significant degree until after the second and third applications of fertilizer. All of the dominant grasses and forbs serve as summer forage for mule deer, moose, elk, and woodland caribou. Fireweed (Epilobium angustifolium), a preferred forage for mule deer, increased in fertilized stands. Grasses and dominant herbs in fertilized stands provide excellent forage and cover habitat for snowshoe hares and Microtus voles. Mean biomass of total shrubs was not affected by fertilization. However, saskatoon berry (Amelanchier alnifolia), prickly rose (Rosa acicularis), and red raspberry (Rubus idaeus) increased significantly in biomass in fertilized stands. Willow (Salix spp.) also increased in biomass, but was variable across treatment stands. Snowshoe hares respond favourably to enhanced shrub growth for food and cover in fertilized stands. All of these shrubs are readily eaten by deer, moose, and elk, and their structural attributes provide security and thermal cover. Mean biomass of understory Douglas-fir (Pseudotsuga menziesii) responded positively to fertilization, but subalpine fir (Abies lasiocarpa) and the three deciduous tree species did not. Dwarf shrubs such as kinnikinnick (Arctostaphylos uva-ursi), twinflower (Linnaea borealis), and dwarf blueberry (Vaccinium caespitosum) declined in fertilized stands. Thus, H1 was partially supported for some species. Increasing cover of grasses and nitrophilous herbs, and canopy cover from rapidly growing crop trees, in fertilized stands may have contributed to the decline of some dwarf shrubs. Mean crown volume index of total mosses and terrestrial lichens declined significantly in fertilized stands, thereby supporting H2. Mean biomass of total grasses (increase), R. acicularis (increase), and V. caespitosum (decline) were significantly affected after one application of fertilizer. Repeated applications of fertilizer may enhance biomass of some additional forage forbs and shrubs, but reduce biomass of some dwarf shrubs, mosses, and lichens. © 2018 Elsevier B.V. Funding details Funding number Funding sponsor Acronym Funding opportunities Department of Agriculture and Rural Development DARD Forestia Simon Fraser University SFU Weyerhaeuser Company Ministry of Environment and Forests MoEF Agriculture and Agri-Food Canada See opportunities Forestia New Zealand Agricultural Greenhouse Gas Research Centre NZAGRC Ministry of Environment and Forests MoEF Funding text We thank the Resources Practices Branch , BC Ministry of Forests, Lands, Natural Resource Operations, and Rural Development , Victoria, BC for funding support to prepare this manuscript. We thank Silviculture Branch, BC Ministry of Forests (MoF), Victoria, BC, the Canada-British Columbia Partnership Agreement on Forest Resource Development (FRDA II) , Forest Renewal BC, Forest Innovation Investment ; Gorman Bros. Lumber Ltd. , Tolko Industries Ltd. , Weyerhaeuser Company Limited , and the Alex Fraser Research Forest , University of BC for financial support during the field project. Operational treatments were conducted by the Silviculture sections of Penticton and Horsefly Forest Districts (MoF). We also thank the BC Ministry of Agriculture, Agriculture and Agri-Food Canada , Growing Forward: a federal-provincial-territorial initiative, and the Agricultural Greenhouse Gases Program for financial and logistical support. We also thank A. Kozak for guidance with statistical analysis and t... ISSN: 03781127 CODEN: FECMD Source Type: Journal Original language: English DOI: 10.1016/j.foreco.2018.03.002 Document Type: Article Publisher: Elsevier B.V. References (97) View in search results format All View all 97 references 1 Albaugh, T.J., Allen, H.L., Dougherty, P.M., Johnsen, K.H. Long term growth responses of loblolly pine to optimal nutrient and water resource availability (2004) Forest Ecology and Management, 192 (1), pp. 3-19. Cited 163 times. doi: 10.1016/j.foreco.2004.01.002 View at Publisher 2 Armleder, H.M., Waterhouse, M.J., Keisker, D.G., Dawson, R.J. 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Cited 17 times. doi: 10.1139/Z10-064 View at Publisher Sullivan, T.P.; Department of Forest and Conservation Sciences, Faculty of Forestry, University of British Columbia, 2424 Main Mall, Vancouver, British Columbia, Canada; email:tom.sullivan@ubc.ca © Copyright 2018 Elsevier B.V., All rights reserved.