Some Strategies for Successful Conservation of Species Populations

Where (often captive-bred) animal species have been successfully reintroduced into natural habitats, some common reintroduction strategies have been deployed.

In New South Wales, Australia, Wilson et al (2020) observed that the following tactics likely contributed to successful reintroduction of the eastern quoll (Dasyurus viverrinus) - translocating only female (and preferably pregnant) founders, scheduling release after mating, and reducing post-release dispersals.

According to Roberts and Luther (2023), some strategies in relation to captive bred birds include supplying them with wild food prior to release, re-introduction into a protected area while preserving their natural habitat, helping the species adjust and settle into the area of release, and feeding after release.

Helpfully, Razzetti and Scali (2011) set out a proposed four-step protocol for reintroduction of captive-bred animals: a feasibility study, a preparation stage, release, and monitoring.

A number of factors could help to explain the success behind species reintroduction projects.

In Canada, for instance, the species most suited for reintroduction would be fecund, land-dwelling, attractive to humans, of sufficient size to bear location-tracing devices, practise a plant-based diet, have a limited home range, and be manageable with less complex behaviours and habits (Gedir et al 2004).

Consistent with Razzetti and Scali (2011)’s recommendation, successful species reintroduction projects often involve a component of ongoing oversight of the released taxa, potentially achieved by integrated knowledge management databases, which facilitates long-term evaluation of the effectiveness of the programme and further modification and adaptation (Schwartz et al 2017)

Of foremost importance, however, is a full comprehension of the reasons behind the decrease of the subject species and their “behavioral ecology and natural history” (Gedir et al 2004:3).

Species reintroduction could be viewed as a hybrid in-situ ex-situ strategy in which species bred or propogated ex situ are then translocated in situ. Indeed, pure in situ or ex situ conservation approaches are not without their limitations.

In situ conservation of biodiversity may not be suitable for all species. First, to prevent harassment, injury, or disaster to species and populations located within the conservation zones, in situ schemes may not be appropriate in places undergoing intense environmental and anthropogenic stressors (Zegeye 2017). Effective conservation via the in situ approach could also be impeded in circumstances where the conservation organizations’ lack of ownership or property rights over the land on which the protected area is located (Zegeye 2017).

Ex situ conservation strategies have been described as a last resort in the event of non-viability of in situ alternatives (Zegeye 2017), to be adopted only in extraordinary situations (IUCN 2022). One reason could be the fact that ex situ programmes necessitate significantly higher expenses, risks, and research requirements (vis-à-vis their in situ counterparts) (Zegeye 2017). A further limitation is the fact that ex situ programme areas should ideally be located within or in proximity to the home range of the taxa or populations in question (IUCN 2002), further curtailing the appropriate range of application of such strategies.

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References:-

• IUCN. (2002). ‘IUCN technical guidelines on the management of ex-situ populations for conservation’.

• Gedir, J.V., Everest, T., and Moehrenschlager, A. (2004) ‘Evaluating the Potential for Species Reintroductions in Canada’. https://www.arlis.org/docs/vol1/69415913/gedir_revised_edited_final_may_16.pdf

• Razzetti, E. and Scali, S. (2011). ‘Reintroduction Schemes for Captive-Bred Animals’. Biodiversity Conservation and Habitat Management Vol II. https://www.eolss.net/sample-chapters/c12/E1-67-07-04.pdf

• Roberts, J.L. and Luther, D. (2023). ‘An exploratory analysis of behavior-based and other management techniques to improve avian conservation translocations’. Biological Conservation Vol 279, Mar 2023, 109941. DOI: 10.1016/j.biocon.2023.109941

• Schwartz, K.R., E.C.M. Parsons, L. Rockwood, and T.C. Wood. (2017). ‘Integrating in-situ and ex-situ data management processes for biodiversity conservation’. Frontiers in Ecology and Evolution 5 2017, p.120.

• Wilson, B.A., Evans, M.J., Batson, W.G., Banks, S.C., Gordon, I.J., Fletcher, D.B., Wimpenny, C., Newport, J., Belton, E., Rypalski, A., Portas, T., and Manning, A.D. (2020). ‘Adapting reintroduction tactics in successive trials increases the likelihood of establishment for an endangered carnivore in a fenced sanctuary’. PLoS One. 2020 Jun 29;15(6):e0234455. doi: 10.1371/journal.pone.0234455. PMID: 32598368; PMCID: PMC7323978.

• Zegeye, H. (2017). ‘In situ and ex situ conservation: Complementary approaches for maintaining biodiversity’. IJRES 4 2017, pp.1–12.