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Effects of linear anthropogenic corridors on insect pollinator movement and diversity, and understory shrub fruit production in the boreal forest of northeastern Alberta

  • Author / Creator
    Nelson, Connor J.
  • Fragmentation of habitats is a primary concern in the conservation of global biodiversity. Anthropogenic linear disturbances, such as roads, trails, and power lines, are a major source of habitat fragmentation worldwide. In Alberta’s boreal forest, a common, pervasive type of disturbance is seismic lines. These long, narrow, clear-cut corridors criss-cross the landscape at densities of up to 50 km/km2 dissecting and fragmenting mature forest environments with early seral ones. Seismic lines are known to affect a wide variety of organisms, such as creating movement barriers for some birds, acting as dispersal corridors for invasive plants, and directing the movement of bears, caribou, wolves, and butterflies. Seismic lines have also been found to increase fruit production for a common understory shrub, Vaccinium myrtilloides, the velvet leaf blueberry. Little is known about the mechanism and specifically how it relates to pollination by insects. In this thesis, I investigate the effects of seismic lines on understory shrub reproduction, with a specific focus on pollination and the behaviour of insect pollinators. First, I assessed how seismic lines affect fruit production of understory shrubs, including V. myrtilloides, and tested whether insect pollination explains these responses. Specifically, I collected data on fruit production and flower visitation by insect pollinators at 12 replicated xeric forest sites, each with a 30 m transect on a seismic line and adjacent forest interior to compare fruit and flower visitations. I found that V. myrtilloides fruit production and pollinator visits on seismic lines were both 3-times higher compared to nearby forest interiors. I also found that pollinator richness was significantly related with fruit production, suggesting that insect pollination is a key mechanism for the observed increase in fruit production on seismic lines. Second, I investigated how the abundance, diversity, and movement of bees, an important group of insect pollinators, responded to the presence of seismic lines. Specifically, I compared pan trap samples placed on seismic lines to those placed in the interior forest and found that bees were 3-times more abundant and 1.5-times more diverse on seismic lines. I also used directional malaise traps to assess if bees preferentially travelled along seismic lines. I found that bees travelled 3-times more frequently along seismic lines and likely use them as travel corridors, potentially expanding their foraging range and thereby increasing interactions between previously isolated plant-pollinator communities. These results suggest that seismic lines affect the movement and behaviour of insect pollinators and change the way they provide pollination services. They also broaden our understanding of how organisms respond to linear anthropogenic corridors with important implications in the conservation of both pollinator and understory plant species in the boreal forest.

  • Subjects / Keywords
  • Graduation date
    Spring 2021
  • Type of Item
    Thesis
  • Degree
    Master of Science
  • DOI
    https://doi.org/10.7939/r3-9wt1-sx52
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.