White Fringed Orchid as indicator of Sphagnum bog integrity

Ecosystem integrity often needs to be evaluated rapidly; indicator species may be used to do so. In this study we aim to evaluate whether White Fringed Orchid is an indicator of ombrotrophic peatland (Sphagnum bog) integrity in northeastern North America. The study was carried out in 113 sampling plots located in 60 bogs of southern Quebec, Canada. Vegetation (species cover and strata) and abiotic variables were collected within the plots and disturbance variables were determined using aerial photographs and satellite imagery. The level of integrity on each plot was assessed by calculating a Floristic Quality Assessment Index (FQAI) and an Anthropogenic Activity Index (AAI). Data were analyzed with ANOVAs, multivariate techniques and logistic multiple regression. Results indicated that the presence and abundance of White Fringed Orchid were positively linked to the FQAI and negatively to the perimeter/area ratio variable, suggesting that this species is most abundant and frequent at sites that are less disturbed and influenced by human activities. ANOVA showed that the AAI was lower in plots with high orchid abundance than in those without, suggesting that the orchid grows in more pristine sites. Our study showed that White Fringed Orchid abundance and presence may be used to rapidly and accurately evaluate Sphagnum bog integrity.