Hostname: page-component-cd9895bd7-7cvxr Total loading time: 0 Render date: 2024-12-29T11:56:37.496Z Has data issue: false hasContentIssue false

Impact of informal timber harvesting on habitat structure and bird assemblages in a coastal forest of the Eastern Cape, South Africa

Published online by Cambridge University Press:  01 September 2020

JESSICA LEAVER*
Affiliation:
Department of Botany and Zoology, Stellenbosch University, Private bag X1, Matieland7602, South Africa.
JOHANN C. CARSTENS
Affiliation:
Wild Bird Trust, Cape Parrot Project, 20 Loch Avenue, Parktown2193, South Africa.
MICHAEL I. CHERRY
Affiliation:
Department of Botany and Zoology, Stellenbosch University, Private bag X1, Matieland7602, South Africa.
*
*Author for correspondence; email: jes.leaver@gmail.com

Summary

African forests are under increasing pressure to supply local, regional, and international demand for timber. Much of this trade is unregulated, such that there is increasing concern regarding the ecological sustainability of this resource use. However, there is a lack of studies investigating the ecological impact of informal timber harvesting in African forests. While forest species have adapted to natural canopy gap dynamics, harvesting may alter natural disturbance regimes, with adverse effects on biodiversity. Information regarding harvest gaps, and concomitant impacts on habitat and biodiversity is thus essential to inform sustainable management. This study compared the frequency and nature of harvest gaps and natural gaps in a coastal forest in the Eastern Cape, South Africa, where informal selective timber harvesting occurs. Habitat condition and bird species richness and composition were compared across intact forest, natural gaps, and harvest gaps. Harvest-created gaps increased the number of canopy gaps by 30%, but were comparable with natural gaps in size. Habitat conditions in harvest gaps represented an intermediate state between intact forest and natural gaps, thereby increasing forest-scale habitat heterogeneity. While bird species richness was not affected, species composition differed across intact forest, harvest gaps and natural gaps, driven by changes in habitat condition, and mediated by species’ feeding and nesting traits. Specifically, insectivores, cavity- and ground-nesting species, and hawking and arboreal probing species were negatively affected by the habitat gradient from intact sites to canopy gap conditions, while nectarivores, omnivores and ball/cup nesting species were positively affected. Thus, while the single-tree selective harvesting method used by informal harvesters largely emulated natural canopy disturbances, the harvest-mediated increase in the frequency of canopy gaps may reduce the abundance of certain bird species sensitive to canopy gap conditions and reduce forest-scale beta-diversity.

Type
Research Article
Copyright
© The Author(s), 2020. Published by Cambridge University Press on behalf of BirdLife International

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Arcilla, N., Holbech, L. H. and O’Donnell, S. (2015) Severe declines of understory birds follow illegal logging in Upper Guinea forests of Ghana, West Africa. Biol. Conserv. 188: 4149.CrossRefGoogle Scholar
Berliner, D. D. (2009) Systematic conservation planning for South Africa’s forest biome: an assessment of the conservation status of South Africa’s forests and recommendations for their conservation. Doctoral thesis, University of Cape Town.Google Scholar
Bibby, C., Burgess, N. and Hill, D. (2000) Bird census techniques. London, UK: Academic Press.Google Scholar
Blake, J. G. and Hoppes, W. G. (1986) Influence of resource abundance on use of tree-fall gaps by birds in an isolated woodlot. The Auk 103: 328340.CrossRefGoogle Scholar
Blondel, J., Ferry, C. and Frochot, B. (1981) Point counts with unlimited distance. Studies in Avian Biol. 6: 414420Google Scholar
Bowen, L. T., Moorman, C. E. and Kilgo, J. C. (2007) Seasonal bird use of canopy gaps in a bottomland forest. Wilson J. Ornithol. 119: 7788.CrossRefGoogle Scholar
Brokaw, N. V. L. (1985) Gap-phase regeneration in a tropical forest. Ecology 66: 682687.CrossRefGoogle Scholar
Brown, A. M., Warton, D. I., Andrew, N. R., Binns, M., Cassis, G., and Gibb, H. (2014) The fourth-corner solution - using predictive models to understand how species traits interact with the environment. Methods Ecol. Evol. 5: 344352.CrossRefGoogle Scholar
Cleary, D. F. R., Boyle, T. J. B., Setyawati, T., Anggraeni, C. D., Van Loon, E. E. and Menken, S. B. J. (2007) Bird species and traits associated with logged and unlogged forest in Borneo. Ecol. Applic. 17: 11841197.CrossRefGoogle ScholarPubMed
Clinton, B. D., Boring, L. R. and Swank, W. T. (1993) Canopy gap characteristics and drought influences in oak forests of the Coweeta Basin. Ecology 74: 15511558.CrossRefGoogle Scholar
Cooper, T. J. G., Wannenburgh, A. M. and Cherry, M. I. (2017) Atlas data indicate forest dependent bird species declines in South Africa. Bird Conserv. Internatn. 27: 337354CrossRefGoogle Scholar
Doledec, S., Chessel, D., ter Braak, C. J. F. and Champely, S. (1996) Matching species traits to environmental variables: a new three-table ordination method. Environ. Ecol. Statist. 3: 143166CrossRefGoogle Scholar
European Commission (2013) Timber trade flows within, to and from eastern and southern African countries. Final Report. Project No. 2011/279408Google Scholar
Fimbel, R. A., Grajal, A. and Robinson, J. G. (2001) The cutting edge: conserving wildlife in logging tropical forests. New York: Columbia University Press.CrossRefGoogle Scholar
Forsman, J. T., Reunanen, P., Jokimäki, J. and Mönkkönen, M. (2010) The effects of small-scale disturbance on forest birds: a meta-analysis. Can. J. For. Res. 40: 18331842.CrossRefGoogle Scholar
Fuller, R. J. (2000) Influence of treefall gaps on distributions of breeding birds within old-growth stands in Białowiez˙a forest, Poland. Condor 102: 267274.CrossRefGoogle Scholar
Gardner, T. A., Barlow, J., Chazdon, R., Ewers, R. M., Harvey, C. A., Peres, C. A. and Sodhi, N. S. (2009) Prospects for tropical forest biodiversity in a human-modified world. Ecol. Lett. 12: 561582.CrossRefGoogle Scholar
Geldenhuys, C. J. and Maliepaard, W. (1983) The causes and sizes of canopy gaps in the Southern Cape forests. South Afr. For. J. 124: 5057Google Scholar
Greenberg, C. H. and Lanham, J. D. (2001) Breeding bird assemblages of hurricane-created gaps and adjacent closed canopy forest in the southern Appalachians. For. Ecol. Manage. 154: 251260.CrossRefGoogle Scholar
Gregory, R. D. and van Strien, A. (2010) Wild bird indicators: using composite population trends of birds as measures of environmental health. Ornithol. Sci. 9: 322.CrossRefGoogle Scholar
Harmon, M. E., Franklin, J. F., Swanson, F. J., Sollins, P., Gregory, S. V., Lattin, J. D., Anderson, N. H., Cline, S. P., Aumen, G., Sedell, J. R., Lienkaemper, G. W., Cromack, K. and Cummins, K. W. (1986) Ecology of coarse woody debris in temperate ecosystems. Advances Ecol. Res. 15: 133276.CrossRefGoogle Scholar
Hsieh, T. C., Ma, K. H. and Chao, A. (2020) iNEXT: iNterpolation and EXTrapolation for species diversity. R package version 2.0.20. http://chao.stat.nthu.edu.tw/wordpress/software-download/.Google Scholar
Jobes, A. P., Nol, E. and Voigt, D. R. (2004) Effects of selection cutting on bird communities in contiguous eastern hardwood forests. J. Wildl. Manage. 68: 5160.CrossRefGoogle Scholar
Johns, A. D. (1988) Effects of “selective” timber extraction on rain forest structure and composition and some consequences for frugivores and folivores. Biotropica 20: 3137.CrossRefGoogle Scholar
Jokimäki, J., Huhta, E., Itämies, J. and Rahko, P. (1998) Distribution of arthropods in relation to forest patch size, edge, and stand characteristics. Can. J. For. Res. 28: 10681072.CrossRefGoogle Scholar
Kern, C. C., Montgomery, R. A., Reich, P. B. and Strong, T. F. (2014) Harvest-created canopy gaps increase species and functional trait diversity of the forest ground-layer community. Forest Sci. 60: 335344.CrossRefGoogle Scholar
Kneeshaw, D. D. and Bergeron, Y. (1998) Canopy gap characteristics and tree replacement in the south-eastern boreal forest. Ecology 79: 783794.CrossRefGoogle Scholar
LaManna, J. A. and Martin, T. E. (2017) Logging impacts on avian species richness and composition differ across latitudes and foraging and breeding habitat preferences: Logging impacts differ across latitudes. Biol. Rev. 92: 16571674.CrossRefGoogle ScholarPubMed
Laska, G. (2001) The disturbance and vegetation dynamics: a review and an alternative framework. Plant Ecol. 157: 7799.CrossRefGoogle Scholar
Leaver, J. and Cherry, M. I. (2020). Informal forest product harvesting in the Eastern Cape, South Africa: A recent assessment. Biol. Conserv. 241. https://doi.org/10.1016/j.biocon.2019.108394CrossRefGoogle Scholar
Leaver, J., Mulvaney, J., Ehlers Smith, D. A., Ehler Smith, Y. C. and Cherry, M. I. (2019) Response of bird functional diversity to forest product harvesting in the Eastern Cape, South Africa. For. Ecol. Manage. 445: 8295.CrossRefGoogle Scholar
Levey, D. J. (1988) Tropical wet forest treefall gaps and distributions of understory birds and plants. Ecology 69: 10761089.CrossRefGoogle Scholar
Martin, T. E. and Karr, J. R. (1986) Patch utilization by migrating birds: resource oriented? Ornis Scand. 17: 165174.CrossRefGoogle Scholar
Mason, N. W. H., Mouillot, D., Lee, W. G. and Wilson, J. B. (2005) Functional richness, functional evenness and functional divergence: the primary components of functional diversity. Oikos 111: 112118.CrossRefGoogle Scholar
Midgley, J. J., Cameron, M. C. and Bond, W. J. (1995) Gap characteristics and replacement patterns in the Knysna Forest, South Africa. J. Veg. Sci. 6: 2936.CrossRefGoogle Scholar
Moorman, C. E. and Guynn, D. C. (2001) Effects of group-selection opening size on breeding bird habitat use in a bottomland forest. Ecol. Applic. 11: 16801691.CrossRefGoogle Scholar
Mori, A. S. (2011) Ecosystem management based on natural disturbances: hierarchical context and non-equilibrium paradigm: Disturbance-based ecological management. J. Appl. Ecol. 48: 280292.CrossRefGoogle Scholar
National Forests Act (1998) National Forests Act of the Republic of South Africa (No. 84 of 1998). Cape Town, South Africa: Government Gazette Vol. 400, No. 19408.Google Scholar
Obiri, J. A. F. (1997) Socio-economic and environmental impacts on the utilisation of the umsimbithi tree Millettia grandis in Eastern Cape: A case study of Mt Thesiger Forest Reserve Pondoland. M.Sc. dissertation, School of Botany and Zoology. Pietermaritzburg, University of Natal, South Africa.Google Scholar
Obiri, J. A. F. (2002) Resource quantification, use and sustainable management of coastal forests in the Eastern Cape Province. Doctoral thesis. School of Botany and Zoology. Pietermaritzburg, University of Natal, South Africa.Google Scholar
Obiri, J. A. F. and Lawes, M. J. (2004) Chance versus determinism in canopy gap regeneration in coastal scarp forest in South Africa. J. Veg. Sci. 15: 539547.CrossRefGoogle Scholar
Ott, R. A. and Juday, G. P. (2002) Canopy gap characteristics and their implications for management in the temperate rainforests of southeast Alaska. For. Ecol. Manage. 159: 271291.CrossRefGoogle Scholar
Phillips, D. L. and Shure, D. J. (1990) Patch-size effects on early succession in southern Appalachian forests. Ecology 71: 204212.CrossRefGoogle Scholar
Pickett, S. T. A. and White, P. S. (1985) The ecology of natural disturbance and patch dynamics. New York: Academic Press.Google Scholar
Politi, N., Hunter, M. and Rivera, L. (2012) Assessing the effects of selective logging on birds in Neotropical piedmont and cloud montane forests. Biodiv. Conserv. 21: 31313155.CrossRefGoogle Scholar
R Core Team (2017) R: a language and environment for statistical computing . Version 3.2.3. Vienna, Austria: R Foundation for Statistical Computing. www.R-project.orgGoogle Scholar
Richards, L. A. and Windsor, D. M. (2007) Seasonal variation of arthropod abundance in gaps and the understorey of a lowland moist forest in Panama. J. Trop. Ecol. 23: 169176.CrossRefGoogle Scholar
Runkle, J. R. (1981) Gap regeneration in some old-growth forests of the eastern United States. Ecology 62: 10411051.CrossRefGoogle Scholar
Sekercioglu, C. H. (2002) Effects of forestry practices on vegetation structure and bird community of Kibale National Park, Uganda. Biol. Conserv. 107: 229240.CrossRefGoogle Scholar
Shure, D. J., Phillips, D. L. and Bostick, E. P.. (2006) Gap size and succession in cutover southern Appalachian forests: an 18 year study of vegetation dynamics. Plant Ecol. 185: 299318.CrossRefGoogle Scholar
Statistics South Africa (2018) South African Statistics. Pretoria. http://www.statssa.gov.za/publications.Google Scholar
Sunderlin, W. D., Dewi, S., Puntodewo, A., Müller, D., Angelsen, A. and Epprecht, M. (2008) Why forests are important for global poverty alleviation: a spatial explanation. Ecol. Soc. 13: 24.CrossRefGoogle Scholar
Thiollay, J. M. (1999) Responses of an avian community to rain forest degradation. Biodivers. Conserv. 8: 513534.CrossRefGoogle Scholar
Vitt, L. J., Avila-Pires, T. C. S., Caldwell, J. P. and Oliveira, V. R. L. (1998) The impact of individual tree harvesting on thermal environments of lizards in Amazonian rain forest. Conserv. Biol. 12: 654664.CrossRefGoogle Scholar
Von Maltitz, G., Mucina, L., Geldenhuys, C. J., Lawes, M. J., Eeley, H. A. C., Adie, H., Vink, D., Fleming, G. and Bailey, C. (2003) Classification system for South African indigenous forests: an objective classification for the Department of Water Affairs and Forestry. Environmentek report ENV-PC 17: 1284.Google Scholar
Wang, Y., Naumann, U., Eddelbuettel, D., Wilshire, J. and Warton, D. (2020) mvabund: Statistical Methods for Analysing Multivariate Abundance Data. R package version 4.1.3. https://CRAN.R-project.org/package=mvabundGoogle Scholar
Wunderle, J. M., Henriques, L. M. P. and Willig, M. R. (2006) Short-term responses of birds to forest gaps and understory: an assessment of reduced-impact logging in a lowland Amazon forest: reduced-impact logging effects on amazon birds. Biotropica 38: 235255.CrossRefGoogle Scholar
Supplementary material: File

Leaver et al. supplementary material

Tables S1-S3 and Figures S1-S4

Download Leaver et al. supplementary material(File)
File 660 KB