Ecological Indicators 14 (2012) 50–55 Contents lists available at SciVerse ScienceDirect Ecological Indicators jo ur n al homep ag e: www.elsevier.com/locate/ecolind White Fringed Orchid as indicator of Sphagnum bog integrity Vincent Laroche, Stéphanie Pellerin ∗ , Luc Brouillet Institut de recherche en biologie végétale, Jardin botanique de Montréal, Université de Montréal, 4101 Sherbrooke Est, Montréal, Québec, Canada H1X 2B2 a r t i c l e i n f o Article history: Received 9 February 2011 Received in revised form 11 July 2011 Accepted 11 August 2011 Keywords: Conservation FQAI Integrity Orchidaceae Peatland Platanthera blephariglottis a b s t r a c t 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 (Sphag- num 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 satel- lite 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. © 2011 Elsevier Ltd. All rights reserved. 1. Introduction Peatlands are wetlands formed through the accumulation of partially decayed organic materials (peat) that represent 50–70% of global wetland resources (Chapman et al., 2003). These ecosystems are important for biodiversity conservation, climate regulation and human welfare. For instance, they contain around one-third of global soil carbon (Gorham, 1991), store great quantities of water (Moore, 2002), and provide unique habitats for many rare and endemic species (Charman, 2002). Although most peatlands in northern North America remain more or less undisturbed, pres- sures are high in inhabited regions (Poulin et al., 2004). Moreover, even seemingly untouched peatlands may experience important vegetation changes owing to the influence of surrounding activi- ties (e.g., Pellerin et al., 2009; Tousignant et al., 2010). Identifying healthier peatlands to be included in a reserve network that will ensure the long-term persistence of target communities is there- fore a challenge. The Floristic Quality Assessment Index (FQAI, Swink and Wilhelm, 1979) is a tool frequently used with success to assess wetland integrity (e.g., Lopez and Fennessy, 2002; Andreas et al., ∗ Corresponding author. Tel.: +1 514 872 2829; fax: +1 514 343 2288. E-mail addresses: vin100.laroche@gmail.com (V. Laroche), stephanie.pellerin.1@umontreal.ca (S. Pellerin), luc.brouillet@umontreal.ca (L. Brouillet). 2004; Cohen et al., 2004; Miller and Wardrop, 2006). For exam- ple, Andreas et al. (2004) found that FQAI of all wetland types had a strong negative correlation with local and regional human disturbances. Some bird and insect species, such as epigeic spi- ders (Scott et al., 2006) and odonates (Bonifait and Villard, 2010), have also been found to be good indicators of peatland condition. Palm Warbler (Dendroica palmarum), a bird in temperate regions mostly restricted to peatlands during the nesting period (Calmé and Desrochers, 1999), is also sensitive to habitat disturbance (Desrochers et al., 1998). The goal of this study was to evaluate whether White Fringed Orchid (Platanthera blephariglottis var. blephariglottis) is an indi- cator of ombrotrophic peatlands (Sphagnum bog) integrity in northeastern North America. White Fringed Orchid is an eastern North American species that grows on acidic soils and mainly in Sphagnum bogs and less frequently in poor minerotrophic peat- lands (fens) or in peaty meadows. Blooming lasts 31–46 days between the end of June and the beginning of August, depending on the latitude and microhabitat (Smith and Snow, 1976; Cole and Firmage, 1984). Like most terrestrial orchids, White Fringed Orchid requires association with symbiotic fungi for seed germination and development (Rasmussen, 1995). A recent study conducted in bogs of Quebec, however, showed that its seeds were able to germinate even in sites where the species was not previously present (Poulin and Laroche, unpublished results), meaning that the presence of fungi is likely not a restrictive factor to the species. White Fringed Orchid is well suited to our purposes as it has been suggested to be 1470-160X/$ – see front matter © 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.ecolind.2011.08.014