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McCaig ML, Kidd KA, Smenderovac EE, Perrotta BG, Emilson CE, Stastny M, Venier L, Emilson EJS. Response of stream habitat and microbiomes to spruce budworm defoliation: New considerations for outbreak management. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2024:e3020. [PMID: 39155464 DOI: 10.1002/eap.3020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 04/09/2024] [Accepted: 05/23/2024] [Indexed: 08/20/2024]
Abstract
Defoliation by eastern spruce budworm is one of the most important natural disturbances in Canadian boreal and hemi-boreal forests with annual area affected surpassing that of fire and harvest combined, and its impacts are projected to increase in frequency, severity, and range under future climate scenarios. Deciding on an active management strategy to control outbreaks and minimize broader economic, ecological, and social impacts is becoming increasingly important. These strategies differ in the degree to which defoliation is suppressed, but little is known about the downstream consequences of defoliation and, thus, the implications of management. Given the disproportionate role of headwater streams and their microbiomes on net riverine productivity across forested landscapes, we investigated the effects of defoliation by spruce budworm on headwater stream habitat and microbiome structure and function to inform management decisions. We experimentally manipulated a gradient of defoliation among 12 watersheds during a spruce budworm outbreak in the Gaspésie Peninsula, Québec, Canada. From May through October of 2019-2021, stream habitat (flow rates, dissolved organic matter [DOM], water chemistry, and nutrients), algal biomass, and water temperatures were assessed. Bacterial and fungal biofilm communities were examined by incubating six leaf packs for five weeks (mid-August to late September) in one stream reach per watershed. Microbiome community structure was determined using metabarcoding of 16S and ITS rRNA genes, and community functions were examined using extracellular enzyme assays, leaf litter decomposition rates, and taxonomic functional assignments. We found that cumulative defoliation was correlated with increased streamflow rates and temperatures, and more aromatic DOM (measured as specific ultraviolet absorbance at 254 nm), but was not correlated to nutrient concentrations. Cumulative defoliation was also associated with altered microbial community composition, an increase in carbohydrate biosynthesis, and a reduction in aromatic compound degradation, suggesting that microbes are shifting to the preferential use of simple carbohydrates rather than more complex aromatic compounds. These results demonstrate that high levels of defoliation can affect headwater stream microbiomes to the point of altering stream ecosystem productivity and carbon cycling potential, highlighting the importance of incorporating broader ecological processes into spruce budworm management decisions.
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Affiliation(s)
- Madison L McCaig
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
- Natural Resources Canada, Canadian Forest Service, Great Lakes Forestry Centre, Sault Ste. Marie, Ontario, Canada
| | - Karen A Kidd
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
- School of Earth, Environment and Society, McMaster University, Hamilton, Ontario, Canada
| | - Emily E Smenderovac
- Natural Resources Canada, Canadian Forest Service, Great Lakes Forestry Centre, Sault Ste. Marie, Ontario, Canada
| | | | - Caroline E Emilson
- Natural Resources Canada, Canadian Forest Service, Great Lakes Forestry Centre, Sault Ste. Marie, Ontario, Canada
| | - Michael Stastny
- Natural Resources Canada, Canadian Forest Service, Atlantic Forestry Centre, Fredericton, New Brunswick, Canada
| | - Lisa Venier
- Natural Resources Canada, Canadian Forest Service, Great Lakes Forestry Centre, Sault Ste. Marie, Ontario, Canada
| | - Erik J S Emilson
- Natural Resources Canada, Canadian Forest Service, Great Lakes Forestry Centre, Sault Ste. Marie, Ontario, Canada
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Lecina-Diaz J, Martínez-Vilalta J, Lloret F, Seidl R. Resilience and vulnerability: distinct concepts to address global change in forests. Trends Ecol Evol 2024; 39:706-715. [PMID: 38531712 DOI: 10.1016/j.tree.2024.03.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 02/29/2024] [Accepted: 03/06/2024] [Indexed: 03/28/2024]
Abstract
Resilience and vulnerability are important concepts to understand, anticipate, and manage global change impacts on forest ecosystems. However, they are often used confusingly and inconsistently, hampering a synthetic understanding of global change, and impeding communication with managers and policy-makers. Both concepts are powerful and have complementary strengths, reflecting their different history, methodological approach, components, and spatiotemporal focus. Resilience assessments address the temporal response to disturbance and the mechanisms driving it. Vulnerability assessments focus on spatial patterns of exposure and susceptibility, and explicitly address adaptive capacity and stakeholder preferences. We suggest applying the distinct concepts of resilience and vulnerability where they provide particular leverage, and deduce a number of lessons learned to facilitate the next generation of global change assessments.
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Affiliation(s)
- Judit Lecina-Diaz
- Technical University of Munich, TUM School of Life Sciences, Ecosystem Dynamics and Forest Management Group, Hans-Carl-von-Carlowitz-Platz 2, 85354, Freising, Germany.
| | - Jordi Martínez-Vilalta
- CREAF, E08193 Bellaterra (Cerdanyola del Vallès), Catalonia, Spain; Universitat Autònoma de Barcelona, E08193 Bellaterra (Cerdanyola del Vallès), Catalonia, Spain
| | - Francisco Lloret
- CREAF, E08193 Bellaterra (Cerdanyola del Vallès), Catalonia, Spain; Universitat Autònoma de Barcelona, E08193 Bellaterra (Cerdanyola del Vallès), Catalonia, Spain
| | - Rupert Seidl
- Technical University of Munich, TUM School of Life Sciences, Ecosystem Dynamics and Forest Management Group, Hans-Carl-von-Carlowitz-Platz 2, 85354, Freising, Germany; Berchtesgaden National Park, Doktorberg 6, 83471 Berchtesgaden, Germany
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Ecological radiations of insects in the Mesozoic. Trends Ecol Evol 2022; 37:529-540. [PMID: 35287981 DOI: 10.1016/j.tree.2022.02.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Revised: 02/18/2022] [Accepted: 02/22/2022] [Indexed: 01/02/2023]
Abstract
The Mesozoic is a key era for the rise of the modern insect fauna. Among the most important evolutionary events in Mesozoic insects are the radiation of holometabolous insects, the origin of eusocial and parasitoid insects, diversification of pollinating insects, and development of advanced mimicry and camouflage. These events are closely associated with the diversification of insect ecological behaviors and colonization of new ecospaces. At the same time, insects had evolved more complex and closer ecological associations with various plants and animals. Mesozoic insects played a key and underappreciated ecological role in reconstructing and maintaining terrestrial ecosystems. A greater understanding of the history of insects may help to mitigate future changes in insect diversity and abundance.
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