Research Accomplishment Reports 2011

Interactions of Emerging Threats and Bark Beetle-Microbial Dynamics in Forest Ecosystems (From W1187)

L.K. Rieske-Kinney, F. Stephen, W. Jacobi, L. Bernier, P. Bonello, D. Shaw
Department of Entomology

 

Non-Technical Summary

A changing set of factors is influencing forests at a scale that some argue is unprecedented in the modern era. Much of the US has experienced catastrophic weather for the past 10 years. Changing climate has altered temperature regimes. Invasive exotic species have altered species composition of landscapes. These are just a few of the factors altering forest susceptibility to insects and pathogens.These effects cascade, as, for example, insects and pathogens alter fire regimes, and with increased temperature and drought, facilitate an increase in the number, size and severity of forest fires.

Changes in land use patterns are intensifying interactions at the forest - human interface, which imposes societal goals on natural ecosystems. Among the demands citizens expect from forested ecosystems are resistance to fire, carbon sequestration, clean water and aesthetic quality.

Society increasingly demands ecosystem services at a time when these ecosystems are changing rapidly. For example, hardwoods are recently becoming important to land managers and the public. In the Intermountain West, land managers have become aware that aspen is a critical species and may be declining. We have little research to guide us in restoration efforts. Sudden oak death is changing the composition of West Coast forests. In Midwestern states, the exotic Emerald Ash borer threatens both urban and wild ash.

Understanding dynamics of insect, pathogen and associated microbes in forests is critical to maintaining the ecosystem services forests provide. Funding for both basic and applied research has declined. We must work collectively to address the problems facing forests today, and to train future professionals so that society does not lose the capacity to respond to new or changing environmental crises.

Our research on interactions among insects and fungi and their diversity is providing conceptual and practical models of how invasive insects and fungi can work to degrade forests. Changing large scale factors are altering forests in ways that we could not predict. Without continued and integrated study of forests, these negative impacts will become the norm and they will deprive society of the ecosystem services that forests provide. Our efforts to characterize insect, fungus and host tree interactions have already provided benefits. We know that some fungi are detrimental to bark beetles, some are beneficial, and some can be either depending on context. Efforts are underway to use fungal population structures as 1) indicators of trends in bark beetle outbreaks; and 2) to manage bark beetle populations.

We understand some system specific dynamics and comparison approaches at individual and local scales, but not at cross scale interactions needed to address today's rapidly changing landscape. We have the tools to address many of the questions; we need a collaborative, multistate, and even an international approach to understand feedbacks among insects, microbial associates, the forests that host them, and the agents of change driving this complex system.

2011 Project Description

Non-native invasive species are gaining a foothold in forests of the US and Kentucky. We are monitoring forest plots to assess the ecological effects of specific exotic invaders. We are assessing vegetative composition and forest structure in forests infested by or susceptible to the hemlock woolly adelgid, sudden oak death, and the emerald ash borer.

We have censused forest plots in 20 counties in eastern and central Kentucky to determine current conditions, and will use these data to project future forests in the wake of invasive species establishment. We are also evaluating vegetation characteristics of chestnut plantings where the Asian chestnut gall wasp has become established.

2011 Impact

Hemlock woolly adelgid induced hemlock mortality is predicted to drastically and significantly reduce the component of eastern hemlock in Kentucky's forests, nearly eliminating this forest type 20 years after adelgid establishment.

Projections of sudden oak death induced oak mortality predict a significant loss of red oaks, but a concomitant increase in white oak basal area and total basal area. The decline of red oak will reduce available hard mast, potentially leading to changes in wildlife distribution patterns.

These changes in forest composition and structure will also likely lead to changes in macroarthropod communities.

2011 Publications

Clark, J.T., S. Fei, L. Liang, and L.K. Rieske. 2012. Mapping eastern hemlock: Comparing classification techniques to evaluate susceptibility of a fragmented and valued resource to an exotic invader, the hemlock woolly adelgid. Forest Ecology and Management 266: 216-222.

Dodd, L.E., M.J. Lacki, and L.K. Rieske. 2011. Habitat associations of Lepidoptera in the Ozark Mountains of Arkansas. Journal of the Kansas Entomological Society, page numbers not avail.

Spaulding, H.L. and L.K. Rieske. 2011. A glimpse at future forests: predicting the effects of Phytophthora ramorum on high-risk forests of southern Appalachia. Biological Invasions 13: 1367-1375.