Landscape Ecology

, Volume 26, Issue 3, pp 341–353 | Cite as

Relative importance of management vs. design for implementation of large-scale ecological networks

  • Corinna S. Bazelet
  • Michael J. Samways
Research Article


Ecological networks (ENs) are used to mitigate landscape-scale habitat loss, and are managed and designed to conserve regional biodiversity. In our study region in southern Africa, ENs of isolated grassland remnants are specifically set aside and managed for conservation, and are complemented by corridor-like power line servitudes which are maintained by regular mowing. Using grasshoppers, a sensitive and reliable bioindicator taxon, we determine whether ENs effectively conserve biodiversity. We used cluster analysis and variation partitioning to select the best subset of environmental variables which explained the patterns of species composition. We then compared the relative importance of environmental variables grouped by the scale of their influence: local-scale variables affected by management practices vs. landscape-scale variables affected by design of ENs. Management was consistently and significantly 2–5 times more influential than design in determining grasshopper assemblages within ENs and servitudes. Servitudes had a higher proportion of bare ground, lower proportion of tall grasses and higher abundance of grasshoppers relative to ENs. Three grasshopper species were strongly associated with servitudes and exhibited traits consistent with early colonizers. As management actions are primarily responsible for vegetation succession, the use of ENs for conservation efforts should first focus on appropriate management strategies, such as fire regime and grass height management before altering the landscape structure (e.g. increasing connectivity or enlarging patches). The conservation implications of these results are that, if ENs are managed and designed for heterogeneity and to simulate multiple successional stages, they may be beneficial for biodiversity conservation.


Bioindicators Cluster analysis Grasshoppers Grassland Mitigation Power line servitudes Variation partitioning South Africa 



We thank B. Gcumisa for field assistance. The Mauerberger Foundation Fund and RUBICODE provided financial support. C. Burchmore, P. Gardiner, G. Kruger, A. Madikane, M. Masango, L. Nel, and D. van Zyl of Mondi and SiyaQhubeka provided maps, accommodation at field sites and technical assistance. D. Nel and M. Kidd assisted with statistical analysis. Ezemvelo KZN Wildlife, iSimangaliso Wetland Park, Mondi Business Paper and SiyaQhubeka Forestry permitted sampling on their holdings. Three anonymous reviewers vastly improved the quality of the manuscript.

Supplementary material

10980_2010_9557_MOESM1_ESM.xls (39 kb)
Supplementary material 1 (XLS 39 kb)


  1. Abensperg-Traun M, Smith GT (1999) How small is too small for small animals? Four terrestrial arthropod species in different-sized remnant woodlands in agricultural Western Australia. Biodivers Conserv 8:709–726CrossRefGoogle Scholar
  2. Armstrong AJ, van Hensbergen HJ (1996) Impacts of afforestation with pines on assemblages of native biota in South Africa. S Afr For J 175:35–42Google Scholar
  3. Batáry P, Orci KM, Báldi A, Kleijn D, Kisbenedek T, Erdős S (2007) Effects of local and landscape scale and cattle grazing intensity on Orthoptera assemblages of the Hungarian Great Plain. Basic Appl Ecol 8:280–290. doi: 10.1016/j.baae.2006.03.012 CrossRefGoogle Scholar
  4. Belyea LR, Lancaster J (1999) Assembly rules within a contingent ecology. Oikos 86:402–416CrossRefGoogle Scholar
  5. Bennett AF (1999) Linkages in the landscape: the role of corridors and connectivity in wildlife conservation. IUCN, Gland, SwitzerlandGoogle Scholar
  6. Berggren Å (2005) Effect of propagule size and landscape structure on morphological differentiation and asymmetry in experimentally introduced Roesel’s bush-crickets. Conserv Biol 19:1095–1102. doi: 10.1111/j.1523-1739.2005.00171.x CrossRefGoogle Scholar
  7. Bieringer G, Zulka KP (2003) Shading out species richness: edge effect of a pine plantation on the Orthoptera (Tettigoniidae and Acrididae) assemblage of an adjacent dry grassland. Biodivers Conserv 12:1481–1495CrossRefGoogle Scholar
  8. Boitani L, Falcucci A, Maiorano L, Rondinini C (2007) Ecological networks as conceptual frameworks or operational tools in conservation. Conserv Biol 21:1414–1422. doi: 10.1111/j.1523-1739.2007.00828.x CrossRefPubMedGoogle Scholar
  9. Borcard D, Legendre P, Drapeau P (1992) Partialling out the spatial component of ecological variation. Ecology 73:1045–1055CrossRefGoogle Scholar
  10. Brown VK (1985) Insect herbivores and plant succession. Oikos 44:17–22CrossRefGoogle Scholar
  11. Bullock WL, Samways MJ (2006) Conservation of flower-arthropod interactions in remnant grassland linkages among pine afforestation. Biodivers Conserv 14:3093–3103. doi: 10.1007/s10531-004-0379-7 CrossRefGoogle Scholar
  12. Chambers BQ, Samways MJ (1998) Grasshopper response to a 40-year experimental burning and mowing regime, with recommendations for invertebrate conservation management. Biodivers Conserv 7:985–1012CrossRefGoogle Scholar
  13. Clarke KR, Warwick RM (2001) Change in marine communities: an approach to statistical analysis and interpretation. PRIMER-E, PlymouthGoogle Scholar
  14. Colwell RK (2009) EstimateS: statistical estimation of species richness and shared species from samples. Version 8.2. User’s guide and application.
  15. Di Giulio M, Edwards PJ, Meister E (2001) Enhancing insect diversity in agricultural grasslands: the roles of management and landscape structure. J Appl Ecol 38:310–319CrossRefGoogle Scholar
  16. Dirsh VM (1965) The African genera of Acridoidea. Anti-Locust Research Centre at the University Press, Cambridge, UKGoogle Scholar
  17. Duelli P, Obrist MK (2003) Regional biodiversity in an agricultural landscape: the contribution of seminatural habitat islands. Basic Appl Ecol 4:129–138CrossRefGoogle Scholar
  18. Eades DC, Otte D (2009) Orthoptera species file online. version 2.0/3.5.
  19. Engle DM, Fuhlendorf SD, Roper A, Leslie DM (2008) Invertebrate community response to a shifting mosaic of habitat. Rangeland Ecol Manag 61:55–62CrossRefGoogle Scholar
  20. ESRI (2006) ESRI ArcMAP 9.2. ESRI Inc.
  21. Fahrig L (2003) Effects of habitat fragmentation on biodiversity. Annu Rev Ecol Evol Syst 34:487–515. doi: 10.1146/annurev.ecolsys.34.011802.132419 CrossRefGoogle Scholar
  22. Fischer J, Lindenmayer DB (2007) Landscape modification and habitat fragmentation: a synthesis. Global Ecol Biogeogr 16:265–280. doi: 10.1111/j.1466-8238.2006.00287.x CrossRefGoogle Scholar
  23. Fleishman E, Ray C, Sjogren-Gulve P, Boggs CL, Murphy DD (2002) Assessing the roles of patch quality, area, and isolation in predicting metapopulation dynamics. Conserv Biol 16:706–716CrossRefGoogle Scholar
  24. Gandar MV (1982) The dynamics and trophic ecology of grasshoppers (Acridoidea) in a South African savanna. Oecologia 54:370–378CrossRefGoogle Scholar
  25. Gardiner T, Hassall M (2009) Does microclimate affect grasshopper populations after cutting of hay in improved grassland? J Insect Conserv 13:97–102. doi: 10.1007/s10841-007-9129-y CrossRefGoogle Scholar
  26. Gardiner T, Hill JK, Chesmore D (2005) Review of the methods frequently used to estimate the abundance of Orthoptera in grassland ecosystems. J Insect Conserv 9:151–173. doi: 10.1007/s10841-005-2854-1 CrossRefGoogle Scholar
  27. Gebeyehu S, Samways MJ (2003) Responses of grasshopper assemblages to long-term grazing management in semi-arid African savanna. Agric Ecosyst Environ 95:613–622CrossRefGoogle Scholar
  28. Gilbert-Norton L, Wilson R, Stevens JR, Beard KH (2010) A meta-analytic review of corridor effectiveness. Conserv Biol 24:660–668. doi: 10.1111/j.1523-1739.2010.01450.x CrossRefPubMedGoogle Scholar
  29. Grez A, Zaviezo T, Tischendorf L, Fahrig L (2004) A transient, positive effect of habitat fragmentation on insect population densities. Oecologia 141:444–451. doi: 10.1007/s00442-004-1670-8 CrossRefPubMedGoogle Scholar
  30. Haddad NM (1999) Corridor and distance effects on interpatch movements: a landscape experiment with butterflies. Ecol Appl 9:612–622CrossRefGoogle Scholar
  31. Haddad NM, Bowne DR, Cunningham A, Danielson BJ, Levey DJ, Sargent S, Spira T (2003) Corridor use by diverse taxa. Ecology 84:609–615CrossRefGoogle Scholar
  32. Heikkinen RK, Luoto M, Kuussaari M, Pöyry J (2005) New insights into butterfly–environment relationships using partitioning methods. Proc R Soc Lond B 272:2203–2210. doi: 10.1098/rspb.2005.3212 CrossRefGoogle Scholar
  33. Hilty JA, Lidicker WZ, Merenlender AM (2006) Corridor ecology: the science and practice of linking landscapes for biodiversity conservation. Island Press, Washington, DCGoogle Scholar
  34. Hochkirch A, Adorf F (2007) Effects of prescribed burning and wildfires on Orthoptera in Central European peat bogs. Environ Conserv 34:225–235. doi: 10.1017/S0376892907004006 Google Scholar
  35. Jackleman J, Wistebaar N, Rouget M, Germishuizen S, Summers R (2006) An assessment of the unplanted forestry land holdings in the grasslands biome of Mpumalanga, KwaZulu-Natal and the Eastern Cape. Grasslands: living in a working landscape report no. 8. South African National Biodiversity Institute – Grasslands Programme, PretoriaGoogle Scholar
  36. Jackson ST, Sax DF (2010) Balancing biodiversity in a changing environment: extinction debt, immigration credit and species turnover. Trends Ecol Evol 25:153–160. doi: 10.1016/j.tree.2009.10.001 CrossRefPubMedGoogle Scholar
  37. Jauregui BM, Rosa-Garcia R, Gracia U, Wallis De Vries MF, Osoro K, Celaya R (2008) Effects of stocking density and breed of goats on vegetation and grasshopper occurrence in heathland. Agric Ecosyst Environ 123:219–224. doi: 10.1016/j.agee.2007.06.004 CrossRefGoogle Scholar
  38. Joern A (2004) Variation in grasshopper (Acrididae) densities in response to fire frequency and bison grazing in tallgrass prairie. Environ Entomol 33:1617–1625CrossRefGoogle Scholar
  39. Joern A (2005) Disturbance by fire frequency and bison grazing modulate grasshopper assemblages in tallgrass prairie. Ecology 86:861–873CrossRefGoogle Scholar
  40. Johnsen P (1984) Acridoidea of Zambia. Aarhus University Zoological Laboratory, Aarhus, DenmarkGoogle Scholar
  41. Johnsen P (1991) Acridoidea of Botswana. Aarhus University Zoological Laboratory, Aarhus, DenmarkGoogle Scholar
  42. Jongman RHG, Pungetti G (2004) Ecological networks and greenways—concept design and implementation. Cambridge University Press, CambridgeCrossRefGoogle Scholar
  43. Jonsen ID, Fahrig L (1997) Response of generalist and specialist insect herbivores to landscape spatial structure. Landscape Ecol 12:185–197CrossRefGoogle Scholar
  44. Kleijn D, Sutherland WJ (2003) How effective are European agri-environment schemes in conserving and promoting biodiversity? J Appl Ecol 40:947–969CrossRefGoogle Scholar
  45. Krauss J, Steffan-Dewenter I, Tscharntke T (2003) How does landscape context contribute to effects of habitat fragmentation on diversity and population density of butterflies? J Biogeogr 30:889–900CrossRefGoogle Scholar
  46. Kruess A, Tscharntke T (2002) Grazing intensity and the diversity of grasshoppers, butterflies, and trap-nesting bees and wasps. Conserv Biol 16:1570–1580CrossRefGoogle Scholar
  47. Laurance WF (2008) Theory meets reality: how habitat fragmentation research has transcended island biogeographic theory. Biol Conserv 141:1731–1744. doi: 10.1016/j.biocon.2008.05.011 CrossRefGoogle Scholar
  48. Laurance WF, Yensen E (1991) Predicting the impacts of edge effects in fragmented habitats. Biol Conserv 55:77–92CrossRefGoogle Scholar
  49. Legendre P, Legendre L (1998) Numerical ecology. Elsevier, AmsterdamGoogle Scholar
  50. Lepš J, Šmilauer P (2003) Multivariate analysis of ecological data using CANOCO. Cambridge University Press, CambridgeGoogle Scholar
  51. Lindenmayer DB, Fischer J (2006) Habitat fragmentation and landscape change: an ecological and conservation synthesis. Island Press, WashingtonGoogle Scholar
  52. Magurran AE (2004) Measuring biological diversity. Blackwell, Malden, MAGoogle Scholar
  53. Marini L, Fontana P, Scotton M, Klimek S (2008) Vascular plant and Orthoptera diversity in relation to grassland management and landscape composition in the European Alps. J Appl Ecol 45:361–370. doi: 10.1111/j.1365-2664.2007.01402.x CrossRefGoogle Scholar
  54. McGeoch MA (1998) The selection, testing and application of terrestrial insects as bioindicators. Biol Rev 73:181–201CrossRefGoogle Scholar
  55. McGeoch MA (2007) Insects and bioindication: theory and progress. In: Stewart AJA, New TR, Lewis OT (eds) Insect conservation biology. CABI, Wallingford, UK, pp 144–174CrossRefGoogle Scholar
  56. Mucina L, Rutherford MC (2006) The vegetation of South Africa, Lesotho and Swaziland. South African National Biodiversity Institute, PretoriaGoogle Scholar
  57. Neke KS, du Plessis MA (2004) The threat of transformation: quantifying the vulnerability of grasslands in South Africa. Conserv Biol 18:466–477Google Scholar
  58. Neter J, Kutner MH, Nachtsheim CJ, Wasserman W (1996) Applied linear statistical methods. Irwin, ChicagoGoogle Scholar
  59. Nufio CR, McClenahan JL, Thurston EG (2009) Determining the effects of habitat fragment area on grasshopper species density and richness: a comparison of proportional and uniform sampling methods. Insect Conserv Divers 2:295–304. doi: 10.1111/j.1752-4598.2009.00065.x CrossRefGoogle Scholar
  60. Picaud F, Petit DP (2007) Primary succession of Acrididae (Orthoptera): differences in displacement capacity in early and late colonizers of new habitats. Acta Oecologica 32:59–66. doi: 10.1016/j.actao.2007.03.005 CrossRefGoogle Scholar
  61. Pöyry J, Lindgren S, Salminen J, Kuussaari M (2005) Responses of butterfly and moth species to restored cattle grazing in semi-natural grasslands. Biol Conserv 122:465–478. doi: 10.1016/j.biocon.2004.09.007 CrossRefGoogle Scholar
  62. Pryke SR, Samways MJ (2001) Width of grassland linkages for the conservation of butterflies in South African afforested areas. Biol Conserv 101:85–96CrossRefGoogle Scholar
  63. Pryke SR, Samways MJ (2003) Quality of remnant indigenous grassland linkages for adult butterflies (Lepidoptera) in an afforested African landscape. Biodivers Conserv 12:1985–2004CrossRefGoogle Scholar
  64. Samways MJ (2007a) Implementing ecological networks for conserving insect and other biodiversity. In: Stewart AJA, New TR, Lewis OT (eds) Insect conservation biology. CABI, Wallingford, UK, pp 127–143CrossRefGoogle Scholar
  65. Samways MJ (2007b) Insect conservation: a synthetic management approach. Ann Rev Entomol 52:465–487. doi: 10.1146/annurev.ento.52.110405.091317 CrossRefGoogle Scholar
  66. Samways MJ, Moore SD (1991) Influence of exotic conifer patches on grasshopper (Orthoptera) assemblages in a grassland matrix at a recreational resort, Natal, South Africa. Biol Conserv 57:117–137CrossRefGoogle Scholar
  67. Samways MJ, Bazelet CS, Pryke JS (2010) Provision of ecosystem services by large scale corridors and ecological networks. Biodivers Conserv 19:2949–2962. doi: 10.1007/s10531-009-9715-2 CrossRefGoogle Scholar
  68. SAS Institute (2006) SAS Enterprise Guide (data anaylsis software system), version 4.1. SAS Institute Inc., CaryGoogle Scholar
  69. Siemann E, Haarstad J, Tilman D (1999) Dynamics of plant and arthropod diversity during old field succession. Ecography 22:406–414CrossRefGoogle Scholar
  70. Simberloff D, Farr JA, Cox J, Mehlman DW (1992) Movement corridors—conservation bargains or poor investments. Conserv Biol 6:493–504CrossRefGoogle Scholar
  71. StatSoft I (2009) Statistica (data analysis software system), version 9.0.
  72. Stoner KJ, Joern A (2004) Landscape vs. local habitat scale influences to insect communities from tallgrass prairies remnants. Ecol Appl 14:1306–1320CrossRefGoogle Scholar
  73. Strauss B, Biedermann R (2006) Urban brownfields as temporary habitats: driving forces for the diversity of phytophagous insects. Ecography 29:928–940CrossRefGoogle Scholar
  74. Ter Braak CJF, Šmilauer P (2002) CANOCO reference manual and CanoDraw for Windows user’s guide: software for canonical community ordination (version 4.5). Microcomputer Power, Ithaca, NYGoogle Scholar
  75. van Buskirk J, Willi Y (2004) Enhancement of farmland biodiversity within set-aside land. Conserv Biol 18:987–994CrossRefGoogle Scholar
  76. Wells CN, Williams RS, Walker GL, Haddad NM (2009) Effects of corridors on genetics of a butterfly in a landscape experiment. Southeast Nat 8:709–722CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media B.V. 2010

Authors and Affiliations

  1. 1.Department of Conservation Ecology and EntomologyStellenbosch UniversityMatielandSouth Africa

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