Drought, disease, defoliation and death: forest pathogens as agents of past vegetation change

Abstract

The temperate and boreal forests of Europe and North America have been subject to repeated pathogen (fungal disease and phytophagus insect) outbreaks over the last 100 years. Palaeoecology can, potentially, offer a long-term perspective on such disturbance episodes, providing information on their triggers, frequency and impact. Mid-Holocene declines in Tsuga and Ulmus pollen dominate the Quaternary literature on forest pathogens, yet the role of pathogens, and even the presence of pathogenic fungal diseases, during these events has yet to be established. Pathogen-focused research strategies, informed by the sequence of events documented in modern outbreaks, and undertaken at high temporal resolution using a multi-proxy approach, are required. It is argued that forest pathogens are likely to have been significant agents of past vegetation change, even in cases where climate change was the primary stress factor.

Ecological consequences of human niche construction: Examining long-term anthropogenic shaping of global species distributions

“…The northwest European elm decline (3700-3600 B.C.E.) may have been caused in part by the spread of a pathogen, such as the fungal disease Ophiostoma, carried by the elm bark beetle (Scolytus scolytus), which saw habitat expansion with clearance for agriculture (72).…”

Bark beetles as agents of change in social–ecological systems

“…In scientific and popular publications, the spatial scale and intensity of recent outbreaks are typically portrayed as unprecedented (Raffa et al 2008;Bentz et al 2009), a perception that is due in part to the limited availability of longer-term ecological records to contextualize recent outbreaks (Waller 2013). Improving our understanding of past bark beetle dynamics would be useful for discussing recent outbreaks in terms of commonly used management metrics, such as disturbance return interval (Fettig et al 2007).…”

Reconstructing human impact on peatland development during the past 200 years in CE Europe through biotic proxies and X-ray tomography

“…This type of the forest is really susceptible to droughts that can trigger insect outbreaks (Haynes et al, 2014). There are not many insect outbreaks records published in palaeoecological literature, and the focus was mostly on the bark beetles (Waller, 2013;Morris et al, 2014).…”