Edge effects on understory epiphytic ferns and epiphyllous bryophytes in moist afromontane forests of Ethiopia

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Most studies on edge effects in tropical forests have been conducted in landscapes with low human population density and in situations where the edges have been left unused after logging of the adjacent area. Here we studied forest margins heavily used by local farmers in a forest/agriculture mosaic landscape in Ethiopia. We compared forest structure and plant species composition across 41 forest-agriculture ecotones from 200 m out into the agricultural area to 200 m into the forest. There are strong edge effects from the edge and into the forest on canopy cover and number of stumps and apparently these forest-agricultural edges are intensively used by humans. They are penetrated by paths, beehives are found in the trees, timber of various dimensions is harvested and there is sometimes substantial cover of perennial wild (or semi-wild) crops such as coffee and spices. The number of understory epiphytic fern species as well as number of epiphyllous (i.e., growing on leaves) bryophyte species was lower at 20 m than at 75 m from the edge. The number of fern species was higher in newly created edges and thereafter they declined, which indicates an extinction debt. This pattern was not seen for the epiphyllous bryophytes. It is likely that different human management activities are responsible for many of the found edge effects besides wind and sun effects from the edge. Tropical forest margins provide important resources for people in many landscapes. It is important to understand how such use affects the biota of the forests. This study shows that there are substantial edge effects, but that the edge effects do not seem to become worse over time for epiphyllous bryophytes and only slightly so for ferns.

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  • Anonymous 2010. R Develomment core team. A language and environment for statistical computing. R Foundation for Statistical Computing Vienna.

  • Barthlott W. Schmit-Neuerburg V. Nieder J. & Engwald S. 2001. Diversity and abundance of vascular epiphytes: a comparison of secondary vegetation and primary montane rain forest in the Venezuelan Andes. Plant Ecology152: 145-156.

  • Camargo J. L. & Kapos V. 1995. Complex edge effects on soil moisture and microclimate in central Amazonian forest. J. Trop. Ecol. 11: 205-221.

  • Daniels A. E. D. & Kariyappa K. C. 2007. Bryophyte diversity along gradient of human disturbance in the southern Western Ghats. Curr. Sci. 93: 976-982.

  • Didham R. K. & Lawton J. H. 1999. Edge structure determines the magnitude of changes in microclimate and vegetation structure in tropical forest fragments. Biotropica31: 17-30.

  • Frego K. A. 2007. Bryophytes as potential indicators of forest integrity. Forest Ecology and Management 242: 65-75.

  • Friis I. Demissew S. & van Breugel P. 2010. The Atlas of potential vegetation of Ethiopia. Royal Academy of Science and Letters Copenhagen.

  • Gobeze T. Bekele M. Lemenih M. & Kassa H. 2009. Participatory forest management and its impacts on livelihoods and forest status: the case of Bonga forest in Ethiopia. International Forestry Review 11: 346-358.

  • Harper K. A Macdonald S. E. Burton P. J. Chen J. Brosofske K. D. Saunders S. S. Euskirchen E. S. Roberts D. Jaiteh M. S. & Esseen P. A. 2005. Edge influence on forest structure and composition in fragmented landscapes. Conservation Biology 19: 768-782.

  • Hundera K. Aerts R. de Beenhouwer M. van Overtveld K. Helsen K. Muys B. & Honnay O. 2013. Both forest fragmentation and coffee cultivation negatively affect epiphytic orchid diversity in Ethiopian moist evergreen Afromontane forests. Biol. Conservation 159: 285-291.

  • Hylander K. 2005. Aspect modifies the magnitude of edge effects on bryophyte growth in boreal forests. J. Appl. Ecol. 42: 518-525.

  • Hylander K. & Ehrlén J. 2013. The mechanisms of extinction debts. Trends Ecol. Evol. 28: 341-346.

  • Hylander K. & Hedderson T. A. J. 2007. Does the width of isolated ravine forests influence moss and liverwort diversity and composition? - A study of temperate forests in South Africa. Biodiversity and Conservation 16: 1441-1458.

  • Hylander K. & Nemomissa S. 2008. Home garden coffee as a repository of epiphyte biodiversity in Ethiopia. Frontiersin Ecology and the Environment 6: 524-528.

  • Hylander K. & Nemomissa S. 2009. Complementary roles of home gardens and exotic tree plantations as alternative habitats for Ethiopian montane rainforest plant biodiversity. Conservation Biology 23: 400-409.

  • Hylander K. Pócs T. & Nemomissa S. 2010. Liverworts of Southwestern Ethiopian montane forests: ecological and biogeographical notes. J. Bryol. 32: 92-100.Hylander K. Nemomissa S. Delrue J. & Enkosa W. 2013. Effects of coffee management on deforestation rates and forest integrity. Conservation Biology 27: 1031-1040.

  • Laurance W. F. 2000. Do edge effects occur over large spatial scales? Trends Ecol. Evol. 15: 134-135.

  • Löbel S. Snäll T. & Rydin H. 2012. Epiphytic bryophytes near forest edges and on retention trees: reduced growth and reproduction especially in old-growth-forest indicator species. J. Appl. Ecol. 49: 1334-1343.

  • Moen J. & Jonsson B. G. 2003. Edge effects on liverworts and lichens in forest patches in a mosaic of boreal forest and wetland. Conservation Biology 17: 380-388.

  • Murcia C. 1995. Edge effects in fragmented forests - implication for conservation. Trends Ecol. Evol. 10: 58-62.

  • Patiño J. González-Mancebo J. M. & Fernández-Palacios J. M. 2009. Epiphytic bryophytes in Canarian subtropical montane cloud forests: the importance of the time since disturbance and host identity. Canad. J. Forest Res.39: 48-63.

  • Pócs T. 1977. Epiphyllous communities and their distribution in East Africa. Bryophyt. Biblioth. 13: 681-713.

  • Pócs T. 1996. Epiphyllous liverwort diversity at worldwide level and its threat and conservation. Anales Inst. Biol. Univ. Nac. Autón. México Bot. 67: 109-127.

  • Ries L. Fletcher R. J. Jr Battin J. & Sisk T. D. 2004. Ecological responses to habitat edges: Mechanisms models and variability explained. Annual Rev. Ecol. Evol. Syst. 35: 491-522.

  • Schmitt C. B. 2006. Montane rainforest with wild Coffeaarabica in the Bonga region (SW Ethiopia): plant diversity wild coffee management and implications for conservation. Ecology and Development Series 47 ZEF Bonn.

  • Schmitt C. B. Denich M. Demissew S. Friis I. & Boehmer H. J. 2010. Floristic diversity in fragmented Afromontane rainforests: altitudinal variation and conservation importance. Applied Vegetation Science 13: 291-304.

  • Silva M. P. P. & Pôrto K. C. 2010. Spatial structure of bryophyte communities along an edge-interior gradient in an Atlantic Forest remnant in Northeast Brazil. J. Bryol. 32: 101-112.

  • Sonnleitner M. Dullinger S. Wanek W. & Zechmeister H. 2009. Microclimatic patterns correlate with the distribution of epiphyllous bryophytes in a tropical lowland rain forest in Costa Rica. J. Trop. Ecol. 25: 321-330.

  • Teketay D. Lemenih M. Bekele T. Yemshaw Y. Feleke S. Tadesse W. Moges Y. Hunde T. & Nigussie D. 2010. Forest resources and challenges of sustainable forest management and conservation in Ethiopia. In: F. Bongers & T. Tennigkeit (eds) Degraded forests in Eastern Africa:management and restoration pp. 19-64. Earthscan London.

  • Tscharntke T. Zeller M. Guhardja E. & Bidin A. (eds) 2007. Stability of tropical rainforest margins - linking ecological economic and social constrains of land use and conservation. Springer Berlin.

  • Werner F. A. & Gradstein S. R. 2009. Diversity of dry forest epiphytes along a gradient of human disturbance in the tropical Andes. Journal of Vegetation Science 20: 59-68.

  • Zartman C. E. & Shaw A. J. 2006. Metapopulation extinction thresholds in rain forest remnants. Amer. Naturalist167: 177-189.

  • Zartman C. E. & Nascimento H. E. M. 2006. Are habitattracking metacommunities dispersal limited? Inferences from abundance-occupancy patterns of epiphylls in Amazonian forest fragments. Biological Conservation 127: 46-54.

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