Abstract Detail

Ecological Section

HOVEN, BRIAN M [1], GORCHOV , DAVID L [2], KNIGHT, KATHLEEN S [3].

The effect of emerald ash borer-caused canopy gaps on reproduction of an understory invasive shrub.

  Widespread defoliation and gap formation by invasive insect herbivores can lead to extensive changes to forest structure and canopy composition. Emerald ash borer (EAB), Agrilus planipennis, is an invasive forest pest of particular concern to deciduous forests of eastern North America. Mature ash, Fraxinus spp., will succumb to larval feeding in 1-4 years, resulting in forest canopy gaps which could greatly benefit invasive plant species due to dramatic increases in light. Additionally, tree sapling and seedling responses within EAB-generated canopy gaps have major implications for long-term forest composition. 
To investigate the response of understory woody plant communities to EAB-induced ash mortality, we tagged and measured shrubs, tree seedlings, and saplings in plots established for long-term EAB monitoring by the United States Forest Service (USFS). Metrics of interest include recruitment, growth, cover, and fecundity of native and invasive shrubs, with a special focus on the invasive Amur honeysuckle, Lonicera maackii, as well as recruitment and growth of tree seedlings and saplings. Measurements were made in 2012 and 2013, with plans to remeasure in 2014, at 24 sites located throughout western and central Ohio. White-tailed deer density is expected to be an important covariate, and will be estimated by fecal pellet counts. All data collected is pooled with data previously and currently collected by the USFS concerning canopy tree growth, assessment of ash condition, canopy openness, as well as Forest Inventory and Analysis cover data.
Ash decline was most advanced near the initial infestation (Northwest Ohio), but is quickly advancing throughout western and central Ohio. Canopy openness tended to be higher in sites with greater ash basal area and poorer mean ash condition. The most frequent invasive species were L. maackiiand Rosa multiflora.
Whether a L. maackii fruited or not was best predicted by shrub height, in both 2012 and 2013.  Among fruiting L. maackii the best predictor of fruit number was shrub basal area.  Fruiting was not strongly related to canopy conditions, but may be related to subcanopy parameters.   Ultimately we will analyze ash mortality and subcanopy conditions on L. maackii and native tree demography by path analysis, and incorporate these effects into forest vegetation software (FVS) to make long-term forest composition predictions that can inform management following EAB.  

1 - Miami University, Biology Department, 700 E High Street, Pearson Hall 332, Oxford, OH, 45056, USA
2 - Miami University, Biology, 700 East High St., Oxford, Ohio, 45056, United States
3 - USDA Forest Service, 359 Main Rd., Delaware, OH, 43015, United States

Keywords:
Lonicera maackii
invasive species
fruit production
fecundity
disturbance
forest pests.

Presentation Type: Oral Paper:Papers for Sections
Session: 39
Location: Cottonwoods North/Boise Centre
Date: Wednesday, July 30th, 2014
Time: 2:15 PM
Number: 39004
Abstract ID:266
Candidate for Awards:None