, Volume 167, Issue 3, pp 667–676 | Cite as

The island syndrome and population dynamics of introduced rats

  • James C. RussellEmail author
  • David Ringler
  • Aurélien Trombini
  • Matthieu Le Corre
Population ecology - Original Paper


The island syndrome predicts directional changes in the morphology and demography of insular vertebrates, due to changes in trophic complexity and migration rates caused by island size and isolation. However, the high rate of human-mediated species introductions to some islands also increases trophic complexity, and this will reduce the perceived insularity on any such island. We test four hypotheses on the role of increased trophic complexity on the island syndrome, using introduced black rats (Rattus rattus) on two isolated coral atolls in the Mozambique Channel. Europa Island has remained relatively pristine and insular, with few species introductions, whereas Juan de Nova Island has had many species introductions, including predators and competitors of rats, anthropogenically increasing its trophic complexity. In the most insular environments, the island syndrome is expected to generate increases in body size and densities of rodents but decreases in the rates of reproduction and population cycling. Morphology and reproduction were compared using linear regression and canonical discriminant analysis, while density and population cycling were compared using spatially explicit capture–recapture analysis. Results were compared to other insular black rat populations in the Mozambique Channel and were consistent with predictions from the island syndrome. The manifestation of an island syndrome in rodents depends upon the trophic composition of a community, and may not relate to island size alone when many species additions, such as invasions, have occurred. The differing patterns of rodent population dynamics on each island provide information for future rodent eradication operations.


Body-size Demography Density Rattusrattus Spatially explicit capture–recapture 



This research is part of the ALIENS programme funded by ANR biodiversity (ANR-05-BDIV-003-03) and MEDAD programme “Ecosystèmes Tropicaux”. We thank the Préfet des Terres Australes et Antractiques Françaises (TAAF) for authorisation to work in the Iles Eparses, and the Forces Armées de la Zone Sud de l’Océan Indien (FAZSOI) for transport and occasional other logistical support. Thanks to the fieldworkers who trapped rats on all the islands, particularly Fabien Jan on Europa and Thibault Sauvaget on Juan de Nova. Data for Mayotte were kindly provided by Amélie Desvars, Michel Pascal and Gwenael Vourch (INRA–Institut National de la Recherche Agronomique). Thanks to Murray Efford for discussion on implementing ML SECR methods, Brian McArdle for discussion on multivariate methods and Lise Ruffino, Grant Harper, Elaine Murphy, Jörg Ganzhorn and two anonymous referees for comments on the manuscript.


  1. Adler GH, Levins R (1994) The island syndrome in rodent populations. Q Rev Biol 69:473–489PubMedCrossRefGoogle Scholar
  2. Atkinson IAE (1985) The spread of commensal species of Rattus to oceanic islands and their effects on island avifaunas. In: Moors PJ (ed) Conservation of island birds. International Council for Bird Preservation Technical Publication No. 3, Cambridge, pp 35–81Google Scholar
  3. Banks PB, Dickman CR (2000) Effects of winter food supplementation on reproduction, body mass, and numbers of small mammals in montane Australia. Can J Zool 78:1775–1783CrossRefGoogle Scholar
  4. Barker JP, Adolph EF (1953) Survival of rats without water and given sea water. Am J Physiol 173:495–502PubMedGoogle Scholar
  5. Blackburn TM, Petchey OL, Cassey P, Gaston KJ (2005) Functional diversity of mammalian predators and extinction in island birds. Ecology 86:2916–2923CrossRefGoogle Scholar
  6. Blondel J (2000) Evolution and ecology of birds on islands: trends and prospects. Vie et Milieu 50:205–220Google Scholar
  7. Bonnaud E, Vidal E, Zarzoso-Lacoste D, Torre F (2008) Measuring rodent incisors from scats can increase accuracy of predator diet studies. An illustration based on island cats and rats. C R Biol 331:686–691PubMedCrossRefGoogle Scholar
  8. Borchers DL, Efford MG (2008) Spatially explicit maximum likelihood methods for capture–recapture studies. Biometrics 64:377–385PubMedCrossRefGoogle Scholar
  9. Brown JH, Ernest SKM (2002) Rain and rodents: complex dynamics of desert consumers. Bioscience 52:979–987CrossRefGoogle Scholar
  10. Caut S, Casanovas JG, Virgos E, Lozano J, Witmer GW, Courchamp F (2007) Rats dying for mice: modelling the competitor release effect. Austral Ecol 32:858–868CrossRefGoogle Scholar
  11. Cheylan G, Granjon L, Britton-Davidian J (1998) Distribution of genetic diversity within and between Western Mediterranean island populations of the black rat Rattus rattus (L. 1758). Biol J Linn Soc 63:393–408Google Scholar
  12. Clark DB (1980) Population ecology of Rattus rattus across a desert-montane forest gradient in the Galápagos Islands. Ecology 61:1422–1433CrossRefGoogle Scholar
  13. Courchamp F, Langlais M, Sugihara G (2000) Rabbits killing birds: modelling the hyperpredation process. J Anim Ecol 69:154–164CrossRefGoogle Scholar
  14. Foster JB (1964) Evolution of mammals on islands. Nature 202:234–235CrossRefGoogle Scholar
  15. Ganzhorn JU (2003) Effects of introduced Rattus rattus on endemic small mammals in dry deciduous forest fragments of western Madagascar. Anim Conserv 6:147–157CrossRefGoogle Scholar
  16. Gillespie RG, Claridge EM, Roderick GK (2008) Biodiversity dynamics in isolated island communities: interaction between natural and human-mediated processes. Mol Ecol 17:45–57PubMedCrossRefGoogle Scholar
  17. Gliwicz J (1980) Island populations of rodents: their organisation and functioning. Biol Rev 55:109–138CrossRefGoogle Scholar
  18. Goldstein H, Healy MJR (1995) The graphical presentation of a collection of means. J R Stat Soc A 18:175–177CrossRefGoogle Scholar
  19. Goodman SM, Carleton MD (1996) The rodents of the Reserve Naturelle Integrale d’Andringitra, Madagascar. Fieldiana: Zoology (New Series) 85:257–283Google Scholar
  20. Hanski I, Henttonen H, Korpimäki E, Oksanen L, Turchin P (2001) Small rodent dynamics and predation. Ecology 82:1505–1520CrossRefGoogle Scholar
  21. Hansson L (1987) An interpretation of rodent dynamics as due to trophic interactions. Oikos 50:308–318CrossRefGoogle Scholar
  22. Harper GA (2006) Habitat use by three rat species (Rattus spp.) on an island without other mammalian predators. NZ J Ecol 30:321–333Google Scholar
  23. Harper GA, Dickinson KJM, Seddon PJ (2005) Habitat selection by three rat species (Rattus spp.) on Stewart Island/Rakiura, New Zealand. NZ J Ecol 29:251–260Google Scholar
  24. Harris DB, Macdonald DW (2007) Interference competition between introduced black rats and endemic Galápagos rice rats. Ecology 88:2330–2344PubMedCrossRefGoogle Scholar
  25. Hill MJ, Vel T, Shah NJ (2003) The morphology, distribution and conservation implications of introduced rats, Rattus spp. in the granitic Seychelles. Afr J Ecol 41:179–186CrossRefGoogle Scholar
  26. Howald G, Donlan CJ, Galván JP, Russell JC, Parkes J, Samaniego A, Wang Y, Veitch CR, Genovesi P, Pascal M, Saunders A, Tershy B (2007) Invasive rodent eradication on islands. Conserv Biol 21:1258–1268PubMedCrossRefGoogle Scholar
  27. Hughes BJ, Martin GR, Reynolds SJ (2008) Cats and seabirds: effects of feral Domestic Cat Felis silvestris catus eradication on the population of Sooty Terns Onychoprion fuscata on Ascension Island, South Atlantic. Ibis 50:122–131CrossRefGoogle Scholar
  28. Innes JG, King CM, Flux M, Kimberley MO (2001) Population biology of the ship rat and Norway rat in Pureora Forest Park, 1983–1987. NZ J Zool 27:57–78Google Scholar
  29. Jones HP, Tershy BR, Zavaleta ES, Croll DA, Keitt BS, Finkelstein ME, Howald GR (2008) Severity of the effects of invasive rats on seabirds: a global review. Conserv Biol 22:16–26PubMedCrossRefGoogle Scholar
  30. Krebs CJ (1999) Current paradigms of rodent population dynamics—what are we missing? In: Singleton GR, Hinds LA, Leirs H, Zhang Z (eds) Ecologically-based rodent management. ACIAR Monograph No. 59, Canberra, pp 33–48Google Scholar
  31. Krzanowski WJ (2000) Principles of multivariate analysis: a user’s perspective. Oxford University Press, New YorkGoogle Scholar
  32. Le Corre M, Jouventin P (1997) Ecological significance and conservation priorities of Europa Island (western Indian Ocean), with special reference to seabirds. Rev Ecol 52:205–220Google Scholar
  33. Lomolino MV (2005) Body size evolution in insular vertebrates: generality of the island rule. J Biogeogr 32:1683–1699CrossRefGoogle Scholar
  34. Meiri S, Dayan T, Simberloff D (2005) Area, isolation and body size evolution in insular carnivores. Ecol Lett 8:1211–1217PubMedCrossRefGoogle Scholar
  35. Meiri S, Cooper N, Purvis A (2008) The island rule: made to be broken? Proc R Soc Lond B 275:141–148CrossRefGoogle Scholar
  36. Michaux JR, De Bellocq JG, Sarà M, Morand S (2002) Body size increase in insular rodent populations: a role for predators? Glob Ecol Biogeogr 11:427–436CrossRefGoogle Scholar
  37. Miljutin A, Lehtonen JT (2008) Probability of competition between introduced and native rodents in Madagascar: an estimation based on morphological traits. Est J Ecol 57:133–152CrossRefGoogle Scholar
  38. Millien V, Damuth J (2004) Climate change and size evolution in an island rodent species: new perspectives on the island rule. Evolution 58:1353–1360PubMedGoogle Scholar
  39. Norrdahl K, Heinilä H, Klemola T, Korpimäki E (2004) Predator-induced changes in population structure and individual quality of Microtus voles: a large-scale field experiment. Oikos 105:312–324CrossRefGoogle Scholar
  40. Palkovacs EP (2003) Explaining adaptive shifts in body size on islands: a life history approach. Oikos 103:37–44CrossRefGoogle Scholar
  41. Patton JL, Yang SY, Myers P (1975) Genetic and morphologic divergence among introduced rat populations (Rattus rattus) of the Galápagos archipelago, Ecuador. Syst Zool 24:296–310CrossRefGoogle Scholar
  42. Peck DR, Faulquier L, Pinet P, Jaquemet S, Le Corre M (2008) Feral cat diet and impact on sooty terns at Juan de Nova Island, Mozambique Channel. Anim Conserv 11:65–74CrossRefGoogle Scholar
  43. Pergams ORW, Ashley MV (2001) Microevolution in island rodents. Genetica 112–113:245–256PubMedCrossRefGoogle Scholar
  44. Raia P, Meiri S (2006) The island rule in large mammals: paleontology meets ecology. Evolution 60:1731–1742PubMedGoogle Scholar
  45. Rodríguez C, Torres R, Drummond H (2006) Eradicating introduced mammals from a forested tropical island. Biol Conserv 130:98–105CrossRefGoogle Scholar
  46. Rowe KC, Aplin K, Baverstock PR, Moritz C (2011) Recent and rapid speciation with limited morphological disparity in the genus Rattus. Syst Biol 60:188–203PubMedCrossRefGoogle Scholar
  47. Ruscoe WA, Norbury G, Choquenot D (2006) Trophic interactions between native and introduced animal species. In: Allen RB, Lee WG (eds) Biological invasions in New Zealand. Springer, Berlin, pp 247–263CrossRefGoogle Scholar
  48. Russell JC, Clout MN (2004) Modelling the distribution and interaction of introduced rodents on New Zealand offshore islands. Glob Ecol Biogeogr 13:497–507CrossRefGoogle Scholar
  49. Russell JC, Le Corre M (2009) Introduced mammal impacts on seabirds in the Îles Éparses, Western Indian Ocean. Mar Ornithol 37:121–128Google Scholar
  50. Russell JC, Clout MN, McArdle BH (2004) Island biogeography and the species richness of introduced mammals on New Zealand offshore islands. J Biogeogr 31:653–664CrossRefGoogle Scholar
  51. Russell JC, Lecomte V, Dumont Y, Le Corre M (2009) Intraguild predation and mesopredator release effect on long-lived prey. Ecol Model 220:1098–1104CrossRefGoogle Scholar
  52. Russell JC, Gleeson DM, Le Corre M (2011) The origin of Rattus rattus on the Îles Éparses, Western Indian Ocean. J Biogeogr (in press)Google Scholar
  53. Sánchez-Piñero F, Polis GA (2000) Bottom-up dynamics of allochthonous input: direct and indirect effects of seabirds on islands. Ecology 81:3117–3132Google Scholar
  54. Sax DR, Gaines SD, Brown JH (2002) Species invasions exceed extinctions on islands worldwide: a comparative study of plants and birds. Am Nat 160:766–783PubMedCrossRefGoogle Scholar
  55. Singleton GR, Leirs H, Hinds LA, Zhang Z (1999) Ecologically-based management of rodent pests––re-evaluating our approach to an old problem. In: Singleton GR, Hinds LA, Leirs H, Zhang Z (eds) Ecologically-based rodent management. ACIAR Monograph No. 59, Canberra, pp 17–29Google Scholar
  56. Stapp P, Polis GA (2003) Influence of pulsed resources and marine subsidies on insular rodent populations. Oikos 102:111–123CrossRefGoogle Scholar
  57. Tamarin RH, Malecha SR (1971) The population biology of Hawaiian rodents: demographic parameters. Ecology 52:383–394CrossRefGoogle Scholar
  58. Tollenaere C, Brouat C, Duplantier J-M, Rahalison L, Rahelinirina S, Pascal M, Moné H, Mouahid G, Leirs H, Cosson J-F (2010) Phylogeography of the introduced species Rattus rattus in the western Indian Ocean, with special emphasis on the colonization history of Madagascar. J Biogeogr 37:398–410CrossRefGoogle Scholar
  59. Tylianakis JM, Didham RK, Bascompte J, Wardle DA (2008) Global change and species interactions in terrestrial ecosystems. Ecol Lett 11:1351–1363PubMedCrossRefGoogle Scholar
  60. Ventura J, López-Fuster MJ (2000) Morphometric analysis of the black rat, Rattus rattus, from Congreso Island (Chafarinas Archipelago, Spain). Orsis 15:91–102Google Scholar
  61. Vitousek PM, Mooney HA, Lubchenco J, Melillo JM (1997) Human domination of earth’s ecosystems. Science 277:494–499CrossRefGoogle Scholar
  62. Yom-Tov Y, Yom-Tov S, Moller H (1999) Competition, coexistence and adaptation among rodent invaders to Pacific and New Zealand islands. J Biogeogr 26:947–958CrossRefGoogle Scholar
  63. Zavaleta ES, Hobbs RJ, Mooney HA (2000) Viewing invasive species removal in a whole-ecosystem context. Trends Ecol Evol 16:454–459CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  • James C. Russell
    • 1
    • 2
    Email author
  • David Ringler
    • 1
  • Aurélien Trombini
    • 1
  • Matthieu Le Corre
    • 1
  1. 1.ECOMARUniversité de la RéunionSaint DenisFrance
  2. 2.School of Biological Sciences, Department of StatisticsUniversity of AucklandAucklandNew Zealand

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