Edge effects on the lichen genus Lobaria in Atlantic Canadian Forests

Abstract

Clear-cut or mosaic forestry practices are known to reduce biodiversity in harvested areas, but the biodiversity in the remaining adjacent forests is also affected. Interior parts of the forest that become edge have increased light, wind, and temperature, and a decrease in moisture. Species with a narrow range of tolerance to environmental change are most affected. To better understand this 'edge effect' in the Acadian Forest, 20 mature deciduous stands in northeastern New Brunswick were examined that were adjacent to clear-cuts ranging from 6-11 years old. We used lichens as our bioindicators and selected the genus Lobaria because it is particularly sensitive to disturbance, but also common in mature deciduous forests of this region. Three Lobaria species that are known to occur in the Acadian Forest were examined: L. pulmonaria, L. quercizans, and L. scrobiculata. Canopy closure, temperature, and presence data were recorded at the forest edge and at the first occurrence of any of these three species along a transect running directly into the forest (three transects at each stand, 60 total). Our results show that the species selected have a negative response to newly created forest edges. Lobaria pulmonaria was the most tolerant to edge effects followed by L. quercizan and L. scrobiculata. The mean occurrence distance from the forest edge for all three species was 12.12 m (± 5.66). Forest managers can use these findings to better understand the impacts of clear-cutting on the biodiversity that inhabits the edges created in the residual forests.Key words: Conservation, sustainable forest management, Acadian Forest, edge effects, fragmentation, biodiversity RÉSUMÉ C' est un fait reconnu que les pratiques forestières comme la coupe à blanc ou de la coupe en mosaïque réduisent la biodiversité dans les zones exploitées, mais aussi dans les étendues boisées adjacentes. Les zones situées à l'intérieur de la forêt qui deviennent les bordures subissent une augmentation de la luminosité, de la vitesse du vent et de la température, ainsi qu'une diminution de l'humidité. Les espèces qui n' ont qu'une faible tolérance aux perturbations environnementales en sont les plus affectées. Afin de mieux comprendre « l' effet de bordure » dans la forêt acadienne, nous avons étudié 20 peuplements feuillus à maturité du nord-est du Nouveau-Brunswick adjacents à des coupes à blanc datant de 6 à 11 ans. Nous avons choisi d'utiliser les lichens comme bio-indicateurs et particulièrement ceux du genre Lobaria qui s'avère être particulièrement sensible aux perturbations, mais aussi bien adapté aux forêts feuillues matures de la région. L' étude a porté sur trois espèces de Lobaria qui se retrouvent dans la forêt acadienne : L. pulmonaria, L. quercizans et L. scrobiculata. Les observations portaient sur la fermeture du couvert, la température et la présence de ces espèces en bordure de la forêt, ainsi que la première occurrence de n'importe laquelle de ces trois espèces le long d'un transect entrant directement dans la forêt (trois tr...

Edge Effects Reflect the Impact of the Agricultural Matrix on the Corticolous Lichens Found in Fragments of Cerrado Savanna in Central Brazil

“…The effects of the forest edge on epiphytic lichens are well studied (e.g., [15][16][17]), although little is known of these effects in fragments of Neotropical savanna, in particular, those inserted in agricultural matrices. Located on the great plateau of Central Brazil, the Brazilian Cerrado biome covers an area of 2 million km 2 , representing 23% of the country.…”

Relationships between air pollution, population density, and lichen biodiversity in the Niagara Escarpment World Biosphere Reserve

“…Urban climate is also influenced by ‘the urban heat island effect’, caused by heat-absorbing surfaces, such as concrete, as well as increased energy use, raising temperatures to above those of surrounding rural areas (Landsberg 1981; Bolund & Hunhammar 1999). These disturbances, combined with habitat loss and/or fragmentation, have a compounding effect in urban areas that is reducing biodiversity, particularly sensitive species such as lichens (Laurance & Yensen 1991; Henderson 2000; Barry et al 2015).…”

Contributions to the Ontario flora of lichens and allied fungi, with emphasis on the Great Lakes Basin

“…Collections reported here are from old Acer saccharum or Thuja occidentalis-dominated stands in areas with a long forest continuity. The species is likely rare in the study area given its host restriction to Lobaria pulmonaria, a species particularly sensitive to disturbance and restricted to old forests (Barry et al 2016, Hinds & Hinds 2007, Jüriado et al 2011 Arup et al 2013) because of its star-shaped lobes, small size (thalli up to 2 mm in diameter) and soredia that are produced on lobe tips (Wetmore & Káàrnefelt 1998, as C. stellata Wetmore & & Kàrnefelt). It is a mainly Western Cordilleran species ranging from the Baja Peninsula north to British Columbia and east to Montana, where it is found on acidic rock.…”