Impacts of invasive Amur honeysuckle, Lonicera maackii, leaf litter on multiple trophic levels of detritus‐based experimental wetlands

Abstract

1. Wetlands are especially vulnerable to invasive plants because seasonal movements of sediments, water, nutrients, and debris from adjacent terrestrial habitats create ecological conditions suitable for invasion. Lonicera maackii is a relatively abundant and broadly distributed invasive shrub in the eastern U.S.A., yet few studies have simultaneously tested for effects of its leaf litter on multiple trophic levels within wetland food webs.2. Hatching success, hatchling survival, and hatchling size of tadpoles (Acris crepitans) were assessed using a laboratory mesocosm experiment with no-leaf, native-leaf, and L. maackii-leaf treatments. In the field, short-term (c. 3 week) and long-term (c. 2 years) mesocosm experiments assessed the initial and persistent impacts, respectively, of L. maackii on measures of primary productivity, invertebrate abundance and community structure, and oviposition preference and larval survival of Cope's gray treefrog (Hyla chrysoscelis).3. Exposure of eggs to L. maackii leaves reduced body size at hatching and larval survival of newly hatched A. crepitans. In short-term experiments, L. maackii leaves reduced dissolved oxygen levels, filamentous algal biomass, and macroinvertebrate abundance, and altered macroinvertebrate community structure. In long-term experiments, duckweed cover was 15× times greater in mesocosms with L. maackii leaf additions. Oviposition by a local population of H. chrysoscelis was 10× lower in both short-and long-term mesocosms with L. maackii present. 4. Although ecological impacts of L. maackii have been reported for terrestrial systems, our study is the first to demonstrate the simultaneous effects of its leaves on multiple trophic levels within replicated experimental wetlands. The relatively rapid decomposition of L. maackii leaves, and associated pulse of phenolic compounds, is the most likely proximate mechanism of the bottom-up effects we observed. The mechanisms, timing, and significance of effects is predicted to vary among natural wetlands.5. Our study demonstrates multiple ecological impacts of a terrestrial invasive shrub within experimental wetlands. Detailed studies on the specific mechanisms, and their spatial and temporal variability in natural systems, will elucidate management strategies and improve the efficiency of wetland conservation efforts.

Effects of honeysuckle leaf blight (Insolibasidium deformans, Platygloeaceae) on Amur honeysuckle (Lonicera maackii, Caprifoliaceae) stand and stem structure in northern Kentucky

“…It has detrimental effects on herbaceous and woody plant species (Hutchinson and Vankat 1997;Luken et al 1997;Medley 1997;Gould and Gorchov 2000;Collier et al 2002;Gorchov and Trisel 2003;McCarthy 2004, 2007;Miller and Gorchov 2004;McKinney and Goodell 2010;Loomis et al 2015) and animal (Christopher and Cameron 2012;Loomis et al 2014Loomis et al , 2015 and microbial Arthur et al 2012;Shannon et al 2014;Ali et al 2015) communities. It also affects ecosystem water and nutrient dynamics Boyce et al 2012;McEwan et al 2012;Poulette and Arthur 2012;Kolbe et al 2015;Pfeiffer and Gorchov 2015;Hopfensperger et al 2017) and aquatic communities (Watling et al 2011;McNeish et al 2012McNeish et al , 2017Borth et al 2018;Robison et al 2021).Honeysuckle leaf blight (Insolibasidium deformans (C.J. Gould) Oberw.…”