Review of Ecosystem Level Impacts of Emerald Ash Borer on Black Ash Wetlands: What Does the Future Hold?

Abstract

Abstract:The emerald ash borer (EAB) is rapidly spreading throughout eastern North America and devastating ecosystems where ash is a component tree. This rapid and sustained loss of ash trees has already resulted in ecological impacts on both terrestrial and aquatic ecosystems and is projected to be even more severe as EAB invades black ash-dominated wetlands of the western Great Lakes region. Using two companion studies that are simulating short-and long-term EAB infestations and what is known from the literature, we synthesize our current limited understanding and predict anticipated future impacts of EAB on black ash wetlands. A key response to the die-back of mature black ash will be higher water tables and the potential for flooding and resulting changes to both the vegetation and animal communities. Although seedling planting studies have shown some possible replacement species, little is known about how the removal of black ash from the canopy will affect non-ash species growth and regeneration. Because black ash litter is relatively high in nitrogen, it is expected that there will be important changes in nutrient and carbon cycling and subsequent rates of productivity and decomposition. Changes in hydrology and nutrient and carbon cycling will have cascading effects on the biological community which have been scarcely studied. Research to address these important gaps is currently underway and should lead to alternatives to mitigate the effects of EAB on black ash wetland forests and develop management options pre-and post-EAB invasion.

Exploring the Role of Outdoor Recreation to Contribute to Urban Climate Resilience

“…All three climate trends come into play when the current and projected health of Black Ash is considered. Black Ash often grows in wetland areas and have a tremendous capacity to impact local hydrological cycles [46]. Black Ash is also of cultural importance to the Anishinaabe people of the region; the tree provides bark for traditional basket making [47].…”

“…With warmer winters, EAB is expanding its range, in part due to warmer winter overnight temperatures. EAB range is significantly limited by overnight winter temperatures of below −30 • F [46]. With a loss of Black Ash, local water tables in area wetlands may rise dramatically, leaving these wetlands less capable of serving a natural stormwater management role (water retention) and subsequently unable to contribute to flood control.…”

What Are Intermediate-Severity Forest Disturbances and Why Are They Important?

“…Periodic Dendroctonus ponderosae Hopkins outbreaks have maintained stand structural complexity in Pinus contorta Douglas ex Loudon stands [48,49]. Other examples of pathogen and pest-induced intermediate-severity disturbances include Ceratocystis platani Engelbrecht & Harrington [50], Choristoneura freemani Razowski [51], Agrilus planipennis Fairmaire [52,53], and Cryptococcus fagisuga Lindinger-Nectria coccinea var. faginata M.L.…”

Evaluating Adaptive Management Options for Black Ash Forests in the Face of Emerald Ash Borer Invasion

“…Evidence of this biological influence is clearly evident in the diurnal water table signature, with pronounced drawdown during the day when trees transpire followed by slight recharge or stability during the night (Figure 3 inset). Black ash transpiration (and its influence on overall evapotranspiration [ET]) is thought to be greatest when water tables are below the surface and at intermediate depths (~50 cm, [38]). …”

“…Black ash transpiration (and its influence on overall evapotranspiration [ET]) is thought to be greatest when water tables are below the surface and at intermediate depths (~50 cm, [38]). …”