Audrey Legault
Master student
Department of Phytology
Laval University

Supervised by:

Line Rochefort (Regular member)

Research project description

Insect pollinator composition in peatlands restored by the Moss Layer Transfer Technique

Introduction: Pollinators are critical to a majority of terrestrial ecosystems and many angiosperms are dependent on animal pollination for their seed and fruit production. Insect pollinators habitats are degraded by peat extraction, an important industry in Quebec, which requires the removal of vegetation and the lowering of the water table in a peatland. In Canada, the restoration of peatlands after peat extraction involves the Moss Layer Transfer Technique (MLTT), a method that rewets drained sites and reintroduce bryophytes in post-extraction peatlands. This technique is successful in reestablishing peat-accumulating functions and plant communities normally observed in natural peatlands. However, it is still unknown whether this technique is successful in its restoration of insect pollinator communities. The study of pollinators composition in restored peatlands can therefore provide insight on the success of the MLTT and the vegetation required in reestablishing insect pollinators. Objectives: The goal of this project is to evaluate the quality of the habitats restored using the moss-layer transfer technique for the conservation of insect pollinators. This study will compare species composition observed in restored peatlands with natural (undisturbed) and unrestored (disturbed) peatlands. Study sites: Insects were sampled in a variety of peatlands - both ombrotrophic bogs and fens were considered for study sites. Out of those peatlands, eight were undisturbed (reference ecosystem), seven were restored at least 10 years prior to the study using MLTT, and eight were unrestored (post-extraction). A total of 29 peatlands were considered for this study and were located mostly in the St-Lawrence Lowlands of Quebec (20), as well as in New Brunswick, Canada (9). Material and methods: Insects were collected over a period of three years, from 2018 to 2020. Each summer (June to August), we placed pan traps filled with soapy water at each sample site. We placed them on the ground, 5 meters apart, along a 150-meter transect. The bowls were left over for periods of 24 hours and the insects were then preserved in 70% ethanol. This was repeated three times over the course of a summer for a total of nine sampling efforts at each site. Other factors, such as temperature and relative soil humidity were measured. Temperature was assessed using data from Environment Canada and humidity was measured using a W.E.T. sensor along the transects once at the end of spring and once at the end of summer in 2021. Dominant vegetation was assessed using a 1-meter quadrat. Every 5 meters along the same 150-meter transects, we estimated the percent vegetation coverage of four categories: ericaceous species, trees and shrubs, herbaceous species, and bryophytes. Expected results: Previous studies focusing on the restoration of insect communities in wetlands have found that restoration of the habitats using other restoration techniques led to a return of pollinators. In terms of species composition, it is assumed that similarity in vegetation cover will lead to a similarity in insect composition. We hypothesize that because vegetation in restored peatlands is more similar to the vegetation in natural peatlands than in unrestored peatlands, the restored peatland insect pollinator communities will be more similar to natural sites than unrestored ones. In terms of abundance and richness, it is assumed that a higher cover of entomophilous vegetation will lead to higher abundance and richness in insects because of the higher availability of floral resources.

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