Systematic Mapping and Review of Landscape Fire Smoke (LFS) Exposure Impacts on Insects

Abstract

Landscape fire activity is changing in many regions because of climate change. Smoke emissions from landscape fires contain many harmful air pollutants, and beyond the potential hazard posed to human health, these also have ecological impacts. Insects play essential roles in most ecosystems worldwide, and some work suggests they may also be sensitive to smoke exposure. There is therefore a need for a comprehensive review of smoke impacts on insects. We systematically reviewed the scientific literature from 1930 to 2022 to synthesize the current state of knowledge of the impacts of smoke exposure from landscape fires on the development, behavior, and mortality of insects. We found: (1) 42 relevant studies that met our criteria, with 29% focused on the United States of America and 19% on Canada; (2) of these, 40 insect species were discussed, all of which were sensitive to smoke pollution; (3) most of the existing research focuses on how insect behavior responds to landscape fire smoke (LFS); (4) species react differently to smoke exposure, with for example some species being attracted to the smoke (e.g., some beetles) while others are repelled (e.g., some bees). This review consolidates the current state of knowledge on how smoke impacts insects and highlights areas that may need further investigation. This is particularly relevant since smoke impacts on insect communities will likely worsen in some areas due to increasing levels of biomass burning resulting from the joint pressures of climate change, land use change, and more intense land management involving fire.

Effects of Air Pollutants from Wildfires on Downwind Ecosystems: Observations, Knowledge Gaps, and Questions for Assessing Risk

“…Thus, information about the types and loads of pollutants is generally not a limitation on insights into downwind exposures. In contrast, much less common were studies on the effects of these pollutants on downwind ecosystems. − We discuss these limited studies below organized by ecosystem type.…”

“…In our survey, we found limited literature on the downwind terrestrial ecosystem responses from wildfire mobilized materials to the atmosphere. Effects of a range of anthropogenic pollutants on plant and animal communities are known, , but few studies focus on wildfire generated pollutants specifically. − The limited literature shows that fire-mobilized materials do impact downwind terrestrial ecosystems in notable ways including physical, chemical, and biological effects.…”

“…Another question in the Analysis phase is (Q6) given the range in exposure, what are the harmful effects on recipient ecosystem components? This is the biggest knowledge gap; there is little known about the effects of downwind exposure to wildfire derived pollutants for end points of interest. − Without these data, inferences can be made from laboratory or nonwildfire air pollution studies, but studies of the effects of acute and chronic exposure to the mixture of wildfire derived pollutants are needed, including of ecosystems exposed to simultaneous stress from other pressures such as land use change and anthropogenic air pollution. − , …”

“…In general, we found a limited number of studies on the effects of wildfire generated pollutants on downwind ecosystems, consistent with earlier related syntheses. [28][29][30]98 Major information gaps include, but certainly are not restricted to, how downwind pollutants and materials impact terrestrial and aquatic biogeochemical cycling and concentrations (e.g., nutrient concentrations in downwind lakes and reservoirs), as well as information on biological impacts beyond the few studies on limited aquatic taxa and a few plant and bird taxa.…”

“…Far less developed are knowledge of and management tools for evaluating the ecological risk of wildfires to downwind ecosystems. − While exceedances of National Ambient Air Quality Standards due to wildfire emissions are frequently deemed exceptional events not subject to nonattainment designations and regulatory action, wildfires nonetheless present a challenge to resource managers responsible for protecting ecosystems from air pollution. Wildfire emissions add to anthropogenic emissions, such as those from fossil fuel burning.…”