ESR 13:181-189 (2011)  -  DOI: https://doi.org/10.3354/esr00326

New population models help explain declines in the globally rare boreal felt lichen Erioderma pedicellatum in Newfoundland

R. Ian Goudie1,*, Christoph Scheidegger2, Claudia Hanel3, Anne Munier4, Eugene Conway5

1LGL Limited Environmental Research Associates, 388 Kenmount Road, St. John’s, Newfoundland and Labrador A1B 4A5, Canada
2Swiss Federal Institute for Forest, Snow and Landscape Research, WSL Zürcherstr. 111, 8903 Birmensdorf, Switzerland
3Department of Environment and Conservation, Endangered Species Branch, 117 Riverside Drive, PO Box 2007, Corner Brook, Newfoundland and Labrador A2H 7S1, Canada
4Centre for Non Timber Resources, Royal Roads University, 2005 Sooke Rd, Victoria, British Columbia V9B5Y2, Canada
5Newfoundland Lichen Education and Research Group, Box 16, Conception Harbour, Newfoundland and Labrador A0A1Z0, Canada

ABSTRACT: A preliminary population model was developed for the boreal felt lichen Erioderma pedicellatum (Hue) P. M. Jørg. in Newfoundland using life stage data collected in eastern and south-central Newfoundland, Canada. This Critically Endangered epiphytic lichen displayed a life history strategy with high adult survival and low recruitment. Deterministic models in 6 mo to 1 yr intervals were generated, yielding similar results to the overall mean values for the 4 yr of study in eastern Newfoundland. The populations of E. pedicellatum in Newfoundland are predicted by our models to be unsustainable because of adult mortality, and we attribute this problem to a decline in the forests of balsam fir Abies balsamea (Mill) that predominantly support this lichen. In eastern Newfoundland, thalli are located almost entirely on mature to over-mature balsam fir, and there is little regeneration because of heavy browsing by the introduced moose Alces alces population. The current and projected predictors indicate that habitat effects may be important in predicting future population size. An assessment of the stable stage distribution indicated that the current population has more juveniles and fewer apothecia-bearing thalli than projected, meaning the current population likely generated from a different set of survival and recruitment rates. The projected annual population growth rates calculated for 4 yr indicated that populations are declining (λ < 1.0, mean decline ± SD = –0.175 ± 0.079). The elasticity values support the fact that the population growth rates are most sensitive to changes in the survival of necrotic (apothecia-bearing) cohorts. We suggest that conservation is best focused on the inventory and protection of old-growth forests important to this species, the reduction of the introduced moose population and the use of herbivore exclosures in specific core population areas.


KEY WORDS: Demography · Population model · Boreal felt lichen · Stable stage distribution · Elasticity analysis · Old-growth forests · Dispersal · Forest landscapes


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Cite this article as: Goudie RI, Scheidegger C, Hanel C, Munier A, Conway E (2011) New population models help explain declines in the globally rare boreal felt lichen Erioderma pedicellatum in Newfoundland. Endang Species Res 13:181-189. https://doi.org/10.3354/esr00326

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