scholarly journals Potential impacts of insect-induced harvests in the mixed forests of New England

2019 ◽  
Author(s):  
Meghan Graham MacLean ◽  
Jonathan Holt ◽  
Mark Borsuk ◽  
Marla Markowski-Lindsay ◽  
Brett J. Butler ◽  
...  

ABSTRACTForest insects and pathogens (FIPs) have significant impacts on U.S. forests, each year affecting an area nearly three times the area of wildfires and timber harvesting combined. We surveyed family forest owners (FFOs) in the northeastern U.S. and 84% of respondents indicated they would harvest in at least one of the presented FIP infestation scenarios. This harvest response represents a potentially significant shift in the timing, extent, and species selection of harvesting in the Northeast. Here we used the landowner survey, regional forest inventory data, and characteristics of the emerald ash borer (EAB, Agrilus planipennis) invasion to examine the potential for a rapidly spreading FIP to alter harvest regimes and affect regional forest conditions. Twenty-five percent of the FFO parcels in the Connecticut River Watershed in New England are likely to be harvested in response to EAB within 10 years. This prediction represents an increase in harvest frequencies, from 2.9%/yr (historically) to 3.7%/yr, on FFO woodlands. At typical harvest intensities, this would result in 13% of the total aboveground biomass removed through these harvests, with 81% of that biomass from species other than ash, creating a forest disturbance that is over twice the magnitude of the disturbance from EAB alone.

Forests ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 498
Author(s):  
Meghan Graham MacLean ◽  
Jonathan Holt ◽  
Mark Borsuk ◽  
Marla Markowski-Lindsay ◽  
Brett J. Butler ◽  
...  

Forest insects and pathogens have significant impacts on U.S. forests, annually affecting an area nearly three times that of wildfires and timber harvesting combined. However, coupled with these direct effects of forest insects and pathogens are the indirect impacts through influencing forest management practices, such as harvesting. In an earlier study, we surveyed private woodland owners in the northeastern U.S. and 84% of respondents indicated they intended to harvest in at least one of the presented insect invasion scenarios. This harvest response to insects represents a potentially significant shift in the timing, extent, and species selection of harvesting. Here we used the results from the landowner survey, regional forest inventory data, and characteristics of the emerald ash borer (Species: Agrilus planipennis Fairmaire, 1888) invasion to examine the potential for a rapidly spreading invasive insect to alter harvest regimes and affect regional forest conditions. Our analysis suggests that 25% of the woodland parcels in the Connecticut River Watershed in New England may intend to harvest in response to emerald ash borer. If the emerald ash borer continues to spread at its current rate within the region, and therefore the associated management response occurs in the next decade, this could result in an increase in harvest frequencies, from 2.6% year−1 (historically) to 3.7% year−1 through to approximately 2030. If harvest intensities remain at levels found in remeasured Forest Inventory and Analysis plots, this insect-initiated harvesting would result in the removal of 12%–13% of the total aboveground biomass. Eighty-one percent of the removed biomass would be from species other than ash, creating a forest disturbance that is over twice the magnitude than that created by emerald ash borer alone, with the most valuable co-occurring species most vulnerable to biomass loss.


2011 ◽  
Vol 41 (11) ◽  
pp. 2165-2175 ◽  
Author(s):  
Scott A. Pugh ◽  
Andrew M. Liebhold ◽  
Randall S. Morin

The emerald ash borer (EAB) ( Agrilus planipennis Fairmaire) is a nonnative phloem-feeding beetle that was accidentally introduced near Detroit, Michigan, two to three decades ago. North American ash ( Fraxinus spp.) exhibit little or no resistance, and as this insect species expands its range, extensive mortality results. Previous studies of the impacts of EAB, typical of most insect and disease impact studies, utilized data acquired from sites with known infestations and cannot be used to make regional estimates of change on forest land. By contrast, this study investigated the regional impacts of EAB on the affected resource using information from a large-scale forest inventory (Forest Inventory and Analysis program of the US Department of Agriculture, Forest Service) previously implemented to estimate regional forest resources. Results indicate that since 1980, ash has been increasing throughout many of the Great Lakes States but EAB is reversing this trend in recently invaded areas. Within 50 km of the epicenter of the EAB invasion, a major decline was observed after 2004. For growing stock (trees at least 12.7 cm diameter at breast height), average ash volume decreased from 12.7 to 3.2 m3·ha–1 and mortality increased from 0.1 to 1.4 m3·ha–1·year–1 on timberland between the 2004 and 2009 inventories.


Ecosystems ◽  
2021 ◽  
Author(s):  
Stacey K. Olson ◽  
Erica A. H. Smithwick ◽  
Melissa S. Lucash ◽  
Robert M. Scheller ◽  
Robert E. Nicholas ◽  
...  

AbstractEmerald ash borer (EAB; Agrilus planipennis Farimaire) has been found in 35 US states and five Canadian provinces. This invasive beetle is causing widespread mortality to ash trees (Fraxinus spp.), which are an important timber product and ornamental tree, as well as a cultural resource for some Tribes. The damage will likely continue despite efforts to impede its spread. Further, widespread and rapid ash mortality as a result of EAB is expected to alter forest composition and structure, especially when coupled with the regional effects of climate change in post-ash forests. Thus, we forecasted the long-term effects of EAB-induced ash mortality and preemptive ash harvest (a forest management mitigation strategy) on forested land across a 2-million-hectare region in northern Wisconsin. We used a spatially explicit and spatially interactive forest simulation model, LANDIS-II, to estimate future species dominance and biodiversity assuming continued widespread ash mortality. We ran forest disturbance and succession simulations under historic climate conditions and three downscaled CMIP5 climate change projections representing the upper bound of expected changes in precipitation and temperature. Our results suggest that although ash loss from EAB or harvest resulted in altered biodiversity patterns in some stands, climate change will be the major driver of changes in biodiversity by the end of century, causing increases in the dominance of southern species and homogenization of species composition across the landscape.


EPPO Bulletin ◽  
2021 ◽  
Author(s):  
G. Schrader ◽  
R. Baker ◽  
Y. Baranchikov ◽  
L. Dumouchel ◽  
K. S. Knight ◽  
...  

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Judith Mogouong ◽  
Philippe Constant ◽  
Pierre Legendre ◽  
Claude Guertin

AbstractThe microbiome composition of living organisms is closely linked to essential functions determining the fitness of the host for thriving and adapting to a particular ecosystem. Although multiple factors, including the developmental stage, the diet, and host-microbe coevolution have been reported to drive compositional changes in the microbiome structures, very few attempts have been made to disentangle their various contributions in a global approach. Here, we focus on the emerald ash borer (EAB), an herbivorous pest and a real threat to North American ash tree species, to explore the responses of the adult EAB gut microbiome to ash leaf properties, and to identify potential predictors of EAB microbial variations. The relative contributions of specific host plant properties, namely bacterial and fungal communities on leaves, phytochemical composition, and the geographical coordinates of the sampling sites, to the EAB gut microbial community was examined by canonical analyses. The composition of the phyllosphere microbiome appeared to be a strong predictor of the microbial community structure in EAB guts, explaining 53 and 48% of the variation in fungi and bacteria, respectively. This study suggests a potential covariation of the microorganisms associated with food sources and the insect gut microbiome.


2020 ◽  
Vol 96 (8) ◽  
Author(s):  
Judith Mogouong ◽  
Philippe Constant ◽  
Robert Lavallée ◽  
Claude Guertin

ABSTRACT The gut microbial communities of beetles play crucial roles in their adaptive capacities. Environmental factors such as temperature or nutrition naturally affect the insect microbiome, but a shift in local conditions like the population density on a host tree could also lead to changes in the microbiota. The emerald ash borer (EAB), Agrilus planipennis Fairmaire, is an exotic wood borer that causes environmental and economic damage to ash trees in North America. This study aimed to describe the taxonomic structure of the EAB gut microbiome and explore its potential relationship with borer population size. The number of EAB adults collected per tree through a 75 km transect from an epicenter allowed the creation of distinct classes of population density. The Gammaproteobacteria and Ascomycota predominated in bacterial and fungal communities respectively, as determined by sequencing of the bacterial 16S rRNA gene and the fungal internal transcribed spacer ITS2. Species richness and diversity of the bacterial community showed significant dependence on population density. Moreover, α-diversity and β-diversity analysis revealed some indicator amplicon sequence variants suggesting that the plasticity of the gut microbiome could be related to the EAB population density in host trees.


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