, Volume 166, Issue 1, pp 131–140 | Cite as

Population sinks resulting from degraded habitats of an obligate life-history pathway

Population ecology - Original Paper


Many species traverse multiple habitats across ecosystems to complete their life histories. Degradation of critical, life stage-specific habitats can therefore lead to population bottlenecks and demographic deficits in sub-populations. The riparian zone of waterways is one of the most impacted areas of the coastal zone because of urbanisation, deforestation, farming and livestock grazing. We hypothesised that sink populations can result from alterations of habitats critical to the early life stages of diadromous fish that use this zone, and tested this with field-based sampling and experiments. We found that for Galaxias maculatus, one of the most widely distributed fishes of the southern hemisphere, obligate riparian spawning habitat was very limited and highly vulnerable to disturbance across 14 rivers in New Zealand. Eggs were laid only during spring tides, in the highest tidally influenced vegetation of waterways. Egg survival increased to >90% when laid in three riparian plant species and where stem densities were great enough to prevent desiccation, compared to no survival where vegetation was comprised of other species or was less dense. Experimental exclusion of livestock, one of the major sources of riparian degradation in rural waterways, resulted in quick regeneration, a tenfold increase in egg laying by fish and a threefold increase in survival, compared to adjacent controls. Overall, there was an inverse relationship between river size and egg production. Some of the largest rivers had little or no spawning habitat and very little egg production, effectively becoming sink populations despite supporting large adult populations, whereas some of the smallest pristine streams produced millions of eggs. We demonstrate that even a wide-ranging species with many robust adult populations can be compromised if a stage-specific habitat required to complete a life history is degraded by localised or more diffuse impacts.


Attractive sinks Diadromous fishes Galaxias maculatus Habitat quality Source-sink dynamics 

Supplementary material

442_2010_1834_MOESM1_ESM.pdf (118 kb)
Supplementary material 1 (PDF 118 kb)


  1. Allibone R, Boubée J, West D (1999) The ones that got away: determining whitebait movements and rates of escape. Water Atmos 7:11–13Google Scholar
  2. Anon (2004) Water bodies of national importance: potential water bodies of national importance for recreational value. New Zealand Ministry for the Environment, WellingtonGoogle Scholar
  3. Battin J (2004) When good animals love bad habitats: ecological traps and the conservation of animal populations. Conserv Biol 18:1482–1491. doi:10.1111/j.1523-1739.2004.00417.x CrossRefGoogle Scholar
  4. Belsky AJ, Matzke A, Uselman S (1999) Survey of livestock influences on stream and riparian ecosystems in the western United States. J Soil Water Conserv 54:419–431Google Scholar
  5. Benzie V (1968) Some ecological aspects of the spawning behaviour of the common whitebait Galaxias maculatus attenuatus (Jenyns). Proc NZ Ecol Soc 15:31–39Google Scholar
  6. Bush J (2008) West Coast whitebaiters association submission on the proposed Mokihinui River hydro power scheme. West Coast Regional Council, GreymouthGoogle Scholar
  7. Chapman A, Morgan DL, Beatty SJ, Gill HS (2006) Variation in life history of land-locked lacustrine and riverine populations of Galaxias maculatus (Jenyns 1842) in Western Australia. Environ Biol Fish 77:21–37. doi:10.1007/s10641-006-9051-2 CrossRefGoogle Scholar
  8. Delibes M, Ferreras P, Gaona P (2001a) Attractive sinks, or how individual behavioural decisions determine source-sink dynamics. Ecol Lett 4:401–403. doi:10.1046/j.1461-0248.2001.00254.x CrossRefGoogle Scholar
  9. Delibes M, Gaona P, Ferreras P (2001b) Effects of an attractive sink leading into maladaptive habitat selection. Am Nat 158:277–285PubMedCrossRefGoogle Scholar
  10. DeMartini EE (1999) Intertidal spawning. In: Horn MH, Martin KLM, Chotkowski MA (eds) Intertidal fishes: life in two worlds. Academic, San Diego, pp 143–164CrossRefGoogle Scholar
  11. Dias PC (1996) Sources and sinks in population biology. Trends Ecol Evol 11:326–330. doi:10.1016/0169-5347(96)10037-9 PubMedCrossRefGoogle Scholar
  12. Doak DF (1995) Source-sink models and the problem of habitat degradation: general models and applications to the Yellowstone grizzly. Conserv Biol 9:1370–1379CrossRefGoogle Scholar
  13. Geiger R, Aron RH, Todhunter P (2003) The climate near the ground. Rowman & Littlefield, LanhamGoogle Scholar
  14. Gilroy JJ, Sutherland WJ (2007) Beyond ecological traps: perceptual errors and undervalued resources. Trends Ecol Evol 22:351–356. doi:10.1016/j.tree.2007.03.014 PubMedCrossRefGoogle Scholar
  15. Gisbert E, López MA (2008) Impact of glass eel fishery on by-catch fish species: a quantitative assessment. Hydrobiologia 602:87–98. doi:10.1007/s10750-008-9284-5 CrossRefGoogle Scholar
  16. Grimes CB, Kingsford MJ (1996) How do riverine plumes of different sizes influence fish larvae: do they enhance recruitment? Mar Freshw Res 47:191–208CrossRefGoogle Scholar
  17. Gundersen G, Johannesen E, Andreassen HP, Ims RA (2001) Source-sink dynamics: how sinks affect demography of sources. Ecol Lett 4:14–21. doi:10.1046/j.1461-0248.2001.00182.x CrossRefGoogle Scholar
  18. Hickford MJH, Schiel DR (2003) Comparative dispersal of larvae from demersal versus pelagic spawning fishes. Mar Ecol Prog Ser 252:255–271. doi:10.3354/meps252255 CrossRefGoogle Scholar
  19. Hickford MJH, Cagnon M, Schiel DR (2010) Predation, vegetation and habitat-specific survival of terrestrial eggs of a diadromous fish, Galaxias maculatus (Jenyns, 1842). J Exp Mar Biol Ecol 385:66–72. doi:10.1016/j.jembe.2010.01.010 CrossRefGoogle Scholar
  20. Johnson DM (2004) Source-sink dynamics in a temporally, heterogeneous environment. Ecology 85:2037–2045CrossRefGoogle Scholar
  21. Kappel CV (2005) Losing pieces of the puzzle: threats to marine, estuarine, and diadromous species. Front Ecol Environ 3:275–282CrossRefGoogle Scholar
  22. Kauffman JB, Krueger WC (1984) Livestock impacts on riparian ecosystems and streamside management implications—a review. J Range Manage 37:430–438CrossRefGoogle Scholar
  23. Kawecki TJ (2008) Adaptation to marginal habitats. Annu Rev Ecol Evol S 39:321–342. doi:10.1146/annurev.ecolsys.38.091206.095622 CrossRefGoogle Scholar
  24. Kawecki TJ, Holt RD (2002) Evolutionary consequences of asymmetric dispersal rates. Am Nat 160:333–347PubMedCrossRefGoogle Scholar
  25. Kennish MJ (2002) Environmental threats and environmental future of estuaries. Environ Conserv 29:78–107. doi:10.1017/s0376892902000061 CrossRefGoogle Scholar
  26. Kinlan BP, Gaines SD, Lester SE (2005) Propagule dispersal and the scales of marine community process. Divers Distrib 11:139–148. doi:10.1111/j.1366-9516.2005.00158.x CrossRefGoogle Scholar
  27. Lucas MC, Bubb DH, Jang MH, Ha K, Masters JEG (2009) Availability of and access to critical habitats in regulated rivers: effects of low-head barriers on threatened lampreys. Freshw Biol 54:621–634. doi:10.1111/j.1365-2427.2008.02136.x CrossRefGoogle Scholar
  28. Martin KLM, Van Winkle RC, Drais JE, Lakisic H (2004) Beach-spawning fishes, terrestrial eggs, and air breathing. Physiol Biochem Zool 77:750–759PubMedCrossRefGoogle Scholar
  29. McDowall RM (1965) The composition of the New Zealand whitebait catch, 1964. NZ J Sci 8:285–300Google Scholar
  30. McDowall RM (1968) Galaxias maculatus (Jenyns), the New Zealand Whitebait. NZ Mar Dept Fish Res Bull 2:1–83Google Scholar
  31. McDowall RM (1993) Implications of diadromy for the structuring and modelling of riverine fish communities in New Zealand. NZ J Mar Freshw Res 27:453–462CrossRefGoogle Scholar
  32. McDowall RM, Charteris SC (2006) The possible adaptive advantages of terrestrial egg deposition in some fluvial diadromous galaxiid fishes (Teleostei : Galaxiidae). Fish Fish 7:153–164. doi:10.1111/j.1467-2979.2006.00217.x Google Scholar
  33. McDowall RM, Eldon GA (1980) The ecology of whitebait migrations (Galaxiidae: Galaxias spp.). Fish Res Bull NZ Min Agric Fish 20:1–172Google Scholar
  34. McDowall RM, Mitchell CP, Brothers EB (1994) Age at migration from the sea of juvenile Galaxias in New Zealand (Pisces, Galaxiidae). Bull Mar Sci 54:385–402Google Scholar
  35. McKeown BA (1984) Fish migration. Croom Helm, LondonGoogle Scholar
  36. Metcalfe JD, Arnold GP, McDowall RM (2002) Migration. In: Hart PJB, Reynolds JD (eds) Fish biology. Handbook of fish biology and fisheries, vol 1. Blackwell, Oxford, pp 175–199Google Scholar
  37. Nehlsen W, Williams JE, Lichatowich JA (1991) Pacific salmon at the crossroads: stocks at risk from California, Oregon, Idaho, and Washington. Fisheries 16:4–21Google Scholar
  38. Pollard DA (1971) The biology of a landlocked form of normally catadromous Salmoniform fish Galaxias maculatus (Jenyns) I. Life-cycle and origin. Aust J Mar Freshw Res 22:91–123CrossRefGoogle Scholar
  39. Pulliam HR (1988) Sources, sinks, and population regulation. Am Nat 132:652–661CrossRefGoogle Scholar
  40. Pulliam HR (1996) Sources and sinks: empirical evidence and population consequences. In: Rhodes OE Jr, Chesser RK, Smith MH (eds) Population dynamics in ecological space and time. University of Chicago Press, Chicago, pp 45–69Google Scholar
  41. Remeš V (2000) How can maladaptive habitat choice generate source-sink population dynamics? Oikos 91:579–582CrossRefGoogle Scholar
  42. Richardson J, Jowett I, Smith J, Christiansen R, Christiansen B (2000) Inanga comings and goings—what happens to the whitebait that do get away? Water Atmos 8:6–7Google Scholar
  43. Robinson SK, Thompson FR, Donovan TM, Whitehead DR, Faaborg J (1995) Regional forest fragmentation and the nesting success of migratory birds. Science 267:1987–1990. doi:10.1126/science.267.5206.1987 PubMedCrossRefGoogle Scholar
  44. Romanelli M, Colloca F, Giovanardi O (2002) Growth and mortality of exploited Sardina pilchardus (Walbaum) larvae along the western coast of Italy. Fish Res 55:205–218. doi:10.1016/S0165-7836(01)00286-7 CrossRefGoogle Scholar
  45. Rowe DK, Saxton BA, Stancliff AG (1992) Species composition of whitebait (Galaxiidae) fisheries in 12 Bay of Plenty rivers, New Zealand: evidence for river mouth selection by juvenile Galaxias brevipinnis (Günther). NZ J Mar Freshw Res 26:219–228CrossRefGoogle Scholar
  46. Schtickzelle N, Quinn TP (2007) A metapopulation perspective for salmon and other anadromous fish. Fish Fish 8:297–314. doi:10.1111/j.1467-2979.2007.00256.x Google Scholar
  47. Sokal RR, Rohlf FJ (1981) Biometry, 2nd edn. Freeman, New YorkGoogle Scholar
  48. Taylor MJ (2002) The national inanga spawning database: trends and implications for spawning site management. Sci Conserv 188:1–37Google Scholar
  49. Underwood AJ (1997) Experiments in ecology: their logical design and interpretation using analysis of variance. Cambridge University Press, New YorkGoogle Scholar
  50. Waters JM, Dijkstra LH, Wallis GP (2000) Biogeography of a southern hemisphere freshwater fish: how important is marine dispersal? Mol Ecol 9:1815–1821. doi:10.1046/j.1365-294x.2000.01082.x PubMedCrossRefGoogle Scholar
  51. Wells BK, Grimes CB, Sneva JG, McPherson S, Waldvogel JB (2008) Relationships between oceanic conditions and growth of Chinook salmon (Oncorhynchus tshawytscha) from California, Washington, and Alaska, USA. Fish Oceanogr 17:101–125. doi:10.1111/j.1365-2419.2008.00467.x CrossRefGoogle Scholar
  52. Williamson RB, Smith RK, Quinn JM (1992) Effects of riparian grazing and channelisation on streams in Southland, New Zealand 1. Channel form and stability. NZ J Mar Freshw Res 26:241–258CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2010

Authors and Affiliations

  1. 1.Marine Ecology Research Group, School of Biological SciencesUniversity of CanterburyChristchurchNew Zealand

Personalised recommendations