Matrix transformation alters species-area relationships in fragmented coastal forests
- 221 Downloads
Ecological theory suggests that large habitat fragments should harbour more species than small fragments. However, this may depend on the surrounding matrix. Matrices in fragmented landscapes may either amplify or reduce area effects, which could influence predicted extinctions based on species-area relationships (SARs).
To determine the influence of matrix type on SARs.
We surveyed birds within 59 coastal forest fragments in two matrix types, anthropogenic (South Africa) and natural (Mozambique). We classified species as forest specialists or habitat generalists and fitted species-area models to compare how SAR slopes differed among matrix types. We also calculated nestedness and evenness to determine if these varied among matrix type and used logistic regressions to identify species-specific responses to matrix type.
For habitat generalists, SARs were weak within both matrices, while for forest specialists it was strong in the anthropogenic but weak in the natural matrix. In the former, the SAR was similar to those recorded for real islands within archipelagos. Forest specialist assemblages were nested by area within anthropogenic, but not natural matrices. Matrix type did not influence evenness. Area only affected the occurrence of one species when the matrix was natural, compared to 11 species when it was anthropogenic.
Forest specialist bird species conformed to island biogeographic predictions of species loss in forest fragments embedded in anthropogenic, but not natural matrices. Extinctions from small forest fragments might be prevented by conserving natural- or restoring anthropogenic matrices, as well as by increasing forest area.
KeywordsBirds Extinction Forest specialists Habitat generalists Island biogeography Nestedness Anthropogenic habitats
The MOZAL Community Development Trust, BHP Billiton HSC, National Research Foundation, Conservation Ecology Research Unit, Richards Bay Minerals, the Department of Trade and Industry and the University of Pretoria funded the study. Pieter Olivier was supported by an Innovation post-doctoral grant from the National Research Foundation. We also thank the field assistants who assisted with fieldwork and Thomas Matthews for valuable discussions around nestedness metrics.
Funding was provided by National Research Foundation (Grant No. 8817)
- Berliner DD (2009) Systematic conservation planning for South Africas forest biome: an assessment of the conservation status of South Africa’s forests and recommendations for their conservation. University of Cape TownGoogle Scholar
- Bibby CJ, Burgess ND, Hill DA, Mustoe S (2000) Bird Census Techniques, 2nd edn. Academic Press, LondonGoogle Scholar
- Burgess N, Hales J, Underwood E, Dinerstein E, Olson D, Itoua I, Schipper J, Ricketts T, Newman K, Hales J (2004) Terrestrial ecoregions of Africa and Madagascar: a conservation assessment. Island Press Google Scholar
- Burnham KP, Anderson DR (2002) Model selection and multi-model inference: a practical information-theoretic approach, 2nd edn. Springer, New YorkGoogle Scholar
- Chao A (1984) Board of the foundation of the scandinavian journal of statistics nonparametric estimation of the number of classes in a population. Scand J Stat 11:265–270Google Scholar
- Colwell RK (2013) EstimateS: Statistical estimation of species richness and shared species from samplesGoogle Scholar
- Dennis JE, Schnabel RB (1983) Numerical methods for unconstrained optimization and nonlinear equations. classics in applied mathematics, 16. Prentice-Hall, Englewood Cliffs, NJGoogle Scholar
- Development Core Team R (2012) A language and environment for statistical computing. R Foundation for Statistical Computing, ViennaGoogle Scholar
- Eycott A, Watts K, Brandt G, Buyung-Ali L, Bowler D, Stewart G, Pullin A (2010) Do landscape matrix features affect species movement? Collab Environ Evid 44:0–54Google Scholar
- Fahrig L (2003) Effects of habitat fragmentation on biodiversity. Rev Lit Arts Am 34:487–515Google Scholar
- Guilhaumon F, Mouillot D, Gimenez O (2010) mmSAR: an R-package for multimodel species-area relationship inference. Ecography (Cop) 33:420–424Google Scholar
- Guldemond RAR, van Aarde RJ (2010) Forest patch size and isolation as drivers of bird species richness in Maputaland, Mozambique. J Biogeogr 37:1884–1893Google Scholar
- Haddad NM, Brudvig LA, Clobert J, Davies KF, Gonzalez A, Holt RD, Lovejoy TE, Sexton JO, Austin MP, Collins CD, Cook WM, Damschen EI, Ewers RM, Foster BL, Jenkins CN, King AJ, Laurance WF, Levey DJ, Margules CR, Melbourne BA, Nicholls AO, Orrock JL, Song D-X, Townshend JR (2015) Habitat fragmentation and its lasting impact on Earth’s ecosystems. Sci Adv 1:e1500052–e1500052CrossRefPubMedPubMedCentralGoogle Scholar
- Haila Y (2002) A conceptual genealogy of fragmentation research: from island biogeography to landscape ecology A. Ecol Appl 12:321–334Google Scholar
- Hockey PAR, Dean WRJ, Ryan PG (2005) Roberts birds of Southern Africa VII. The John Voelcker Bird Book Fund, Cape TownGoogle Scholar
- Jewitt D, Goodman PS, Erasmus BFN, O'Connor TG, Witowski ET (2015) Systematic land-cover change in KwaZulu-Natal, South Africa : implications for biodiversity : research article. S Afr J Sci 111:01–09Google Scholar
- Küper W, Henning Sommer J, Lovett JC, Mutke J, Linder HP, Beentje HJ, Rompaey RSARV, Chatelain C, Sosef M, Barthlott W (2004) Africa’s hotspots of biodiversity re-defined. Ann Missouri Bot Gard 91:525–535Google Scholar
- Lawes MJ, Eeley HAC, Shackleton BG. (2004) Indigenous forests and woodlands in South Africa: policy, people and practice. University of KwaZulu-Natal Press, KwaZulu-NatalGoogle Scholar
- MacArthur RH, Wilson EO (1967) The theory of island biogeography. Princeton University Press, PrincetonGoogle Scholar
- Oksanen JF, Blanchet G, Kindt R, Legendre P, Minchin PR, O’Hara RB, Simpson GL (2013) Vegan: community ecology package. R package version 2.0-9. R Foundation for Statistical Computing Google Scholar
- Tscharntke T, Tylianakis JM, Rand TA, Didham RK, Fahrig L, Batáry P, Bengtsson J, Clough Y, Crist TO, Dormann CF, Ewers RM, Fründ J, Holt RD, Holzschuh A, Klein AM, Kleijn D, Kremen C, Landis DA, Laurance W, Lindenmayer D, Scherber C, Sodhi N, Steffan-Dewenter I, Thies C, van der Putten WH, Westphal C (2012) Landscape moderation of biodiversity patterns and processes—eight hypotheses. Biol Rev 87:661–685CrossRefPubMedGoogle Scholar
- van Aarde RJ, Guldemond RAR, Olivier PI (2014) Biodiversity status of coastal dune forests in South Africa. In: Maslo B, Lockwood L (eds) Conservation biology. Cambridge University Press, Cambridge, pp 161–179Google Scholar
- Van Wyk AE, Smith GF (2001) Regions of floristic endemism in Southern Africa. Umdaus Press, PretoriaGoogle Scholar
- Von Maltitz G, Mucina L, Geldenhuys CJ, Lawes MJ, Eeley H, Aidie H, Vink D, Fleming G, Bailey C (2003) Classification system for South African indigenous forests: an objective classification for the Department of Water Affairs and Forestry, Environmentek report ENV-PCGoogle Scholar