Individuals a population to conserve make

28 11 2012
Unique in its genus, the saiga antelope inhabits the steppes and semi-desert environments in two sub-species split between Kazakhstan (Saiga tatarica tatarica, ~ 80% of the individuals) and Mongolia (Saiga tatarica mongolica). Locals hunt them for their meat and the (attributed) medicinal properties of male horns. Like many ungulates, the population is sensitive to winter severity and summer drought (which signal seasonal migrations of herds up to 1000 individuals). But illegal poaching has reduced the species from > 1 million in the 1970s to ~ 50000 currently (see RT video). The species has gone extinct in China and Ukraine, and has been IUCN “Critically Endangered” from 2002. The photo shows a male in The Centre for Wild Animals, Kalmykia, Russia (courtesy of Pavel Sorokin).

In a planet approaching 7 billion people, individual identity for most of us goes largely unnoticed by the rest. However, individuals are important because each can promote changes at different scales of social organisation, from families through to associations, suburbs and countries. This is not only true for the human species, but for any species (1).

It is less than two decades since many ecologists started pondering the ways of applying the understanding of how individuals behave to the conservation of species (2-9), which some now refer to as ‘conservation behaviour’ (10, 11). The nexus seems straightforward. The decisions a bear or a shrimp make daily to feed, mate, move or shelter (i.e., their behaviour) affect their fitness (survival + fertility). Therefore, the sum of those decisions across all individuals in a population or species matters to the core themes handled by conservation biology for ensuring long-term population viability (12), i.e., counteracting anthropogenic impacts, and (with the distinction introduced by Cawley, 13) reversing population decline and avoiding population extinction.

To use behaviour in conservation implies that we can modify the behaviour of individuals to their own benefit (and mostly, to the species’ benefit) or define behavioural metrics that can be used as indicators of population threats. A main research area dealing with behavioural modification is that of anti-predator training of captive individuals prior to re-introduction. Laden with nuances, those training programs have yielded contrasting results across species, and have only tested a few instances of ‘success’ after release into the wild (14). For example, captive black-tailed prairie dogs (Cynomys ludovicianus) exposed to stuffed hawks, caged ferrets and rattlesnakes had higher post-release survival than untrained individuals in the grasslands of the North American Great Plains (15). A clear example of a threat metric is aberrant behaviour triggered by hunting. Eleanor Milner-Gulland et al. (16) have reported a 46 % reduction in fertility rates in the saiga antelope (Saiga tatarica) in Russia from 1993-2002. This species forms harems consisting of one alpha male and 12 to 30 females. Local communities have long hunted this species, but illegal poaching for horned males from the early 1990s (17) ultimately led to harems with a female surplus (with an average sex ratio up to 100 females per male!). In them, only a few dominant females seem to reproduce because they engage in aggressive displays that dissuade other females from accessing the males.

Demographics of saiga antelope in the steppes bordering the Caspian Sea (Republic of Kalmykia, Russia). The plots show annual fertility rates as a function of time (upper panel) and proportion of males in reproductive herds (lower panel). Fertility was calculated as the proportion of foetus-bearing females that were shot in February. Fertility collapsed when the proportion of males in reproductive herds dropped between 2000 and 2001.

Two recent papers looking at temporal publication rates have found that the number of conservation studies based on behaviour has not increased faster than the conservation literature as a whole (18), and those studies are mainly (71 %) descriptive – that is, providing no mechanistic/causative component that is often instrumental in the correct design of conservation actions (19). Some authors disagree on whether the mismatch underlines the difficulty of integrating ethology (which mainly works with individuals) into conservation science (which mainly works with populations) (20, 21), and whether it endangers the progress of the entire discipline of behavioural ecology (there is not much behaviour to study if species disappear!, 22, 23, 24).

However, experts do agree that worthwhile behavioural studies in conservation must start with a conservation question – and not the other way round (8, 21). In other words, we are bound to misuse limited resources to protect species if behavioural research sponsored by conservation programs is only done because a species is threatened and/or in hope that one day such research might help its plight. In fact, the proposition applies to any kind of ecological research. It is our responsibility (ecologists) to frame our work in multidisciplinary projects incorporating the cultural, economic, political and social dimensions (and professionals) that determine the exploitation of natural resources.

Salvador Herrando-Pérez

References

  1. Greene, H. W. (2005). Organisms in nature as a central focus for biology. Trends in Ecology & Evolution, 20: 23-27.
  2. Tuomainen, U. & Candolin, U. (2011). Behavioural responses to human-induced environmental change. Biological Reviews, 86: 640-657.
  3. Gordon, D. M. (2011). The fusion of behavioral ecology and ecology. Behavioral Ecology, 22: 225-230.
  4. McDougall, P. T. et al. (2006). Wildlife conservation and animal temperament: causes and consequences of evolutionary change for captive, reintroduced, and wild populations. Animal Conservation, 9: 39-48.
  5. Anthony, L. L. & Blumstein, D. T. (2000). Integrating behaviour into wildlife conservation: the multiple ways that behaviour can reduce Ne. Biological Conservation, 95: 303-315.
  6. Caro, T. (1999). The behaviour-conservation interface. Trends in Ecology & Evolution, 14: 366-369.
  7. Martin, K. (1998). The role of animal behavior studies in wildlife science and management. Wildlife Society Bulletin, 26: 911-920.
  8. Sutherland, W. J. (1998). The importance of behavioural studies in conservation biology. Animal Behaviour, 56: 801-809.
  9. Curio, E. (1996). Conservation needs ethology. Trends in Ecology & Evolution, 11: 260-263.
  10. Blumstein, D. T. & Fernández-Juricic, E. (2010). A Primer of Conservation Behaviour. Sinauer Press.
  11. Blumstein, D. T. & Fernández-Juricic, E. (2004). The emergence of conservation behavior. Conservation Biology, 18: 1175-1177.
  12. Soulé, M. E. (1985). What is conservation biology? BioScience, 35: 727-734.
  13. Caughley, G. (1994). Directions in conservation biology. Journal of Animal Ecology, 63: 215-244.
  14. Griffin, A. S. et al. (2000). Training captive-bred or translocated animals to avoid predators. Conservation Biology, 14: 1317-1326.
  15. Shier, D. M. & Owings, D. H. (2006). Effects of predator training on behavior and post-release survival of captive prairie dogs (Cynomys ludovicianus). Biological Conservation, 132: 126-135.
  16. Milner-Gulland, E. J. et al. (2003). Reproductive collapse in saiga antelope harems. Nature, 422: 135-135.
  17. Kühl, A. et al. (2009). The role of saiga poaching in rural communities: Linkages between attitudes, socio-economic circumstances and behaviour. Biological Conservation, 142: 1442-1449.
  18. Angeloni, L. et al. (2008). A reassessment of the interface between conservation and behaviour. Animal Behaviour, 75: 731-737.
  19. Linklater, W. L. (2004). Wanted for conservation research: Behavioral ecologists with a broader perspective. BioScience, 54: 352-360.
  20. Buchholz, R. (2007). Behavioural biology: an effective and relevant conservation tool. Trends in Ecology & Evolution, 22: 401-407.
  21. Caro, T. (2007). Behavior and conservation: a bridge too far? Trends in Ecology & Evolution, 22: 394-400.
  22. Caro, T. & Sherman, P. W. (2011). Endangered species and a threatened discipline: behavioural ecology. Trends in Ecology & Evolution, 26: 111-118.
  23. Schroeder, J. et al. (2011). Behavioural ecology is not an endangered discipline. Trends in Ecology & Evolution, 26: 320-321.
  24. Knight, J. (2001). If they could talk to the animals… Nature, 414: 246-247.

 


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20 01 2013
What is ethology, anyway? | Behaving Animals

[…] Individuals a population to conserve make […]

3 12 2012
250,000 gazelles in Mongolia | Dear Kitty. Some blog

[…] Individuals a population to conserve make (conservationbytes.com) […]

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