The long-termeffect of over-supplementation on recovered populations: why restraint is a virtue PAWE Ł ADAMSKI and ADAM M. ĆMIEL


Abstract We present a long-term analysis of the results of the Apollo butterfly Parnassius apollo recovery project in the Pieniny National Park, southern Poland, using a classic- al population ecology model. Six possible theoretical models of changes in population abundance were constructed and their predictions compared with current data. Models that did not take into account supplementation with captive- reared individuals provided the best fit to the population growth pattern during recovery. This was probably because of the introduction of captive-reared specimens to sites while habitat reconstruction was taking place. In addition, we provide data supporting the hypothesis that a significant reduction in the habitat’s carrying capacity occurred during the restoration project, probably as a result of the population being over-supplemented with captive-reared individuals. Our analysis shows that for a recovery project to be suc- cessful, captive breeding and habitat restoration should be properly coordinated.


Keywords Apollo butterfly, captive breeding, carrying ca- pacity, habitat restoration, over-supplementation, Parnassius apollo, population growth, population recovery


or the biological or ecological constraints of the species being restored. Such constraints may relate to the genetic pool and local adaptations (Sarrazin & Barbault, 1996; Moritz, 1999; Hedrick & Kalinowski, 2000;Baums, 2008) or to difficulties ensuing fromrecovery projects being carried out in highly modified ecosystems that had already achieved a resilient alternative state (Bakker & Berendse, 1999;Beisner et al., 2003;Suding et al., 2004; Young et al., 2005). For ani- mals with highly developed nervous systems, distress or be- havioural reactions may affect the outcome of conservation activities, and the implementation of stress-reducing release strategies has been widely discussed (Griffith et al., 1989; Wolf et al., 1998; Moseby et al., 2014). To restore a population and then maintain it in a stable


Introduction


vation (Saint-Jailme, 2002; Seddon et al., 2006; Armstrong & Seddon, 2008; Zając et al., 2018). However, before the late 1980s a significant number of such projects failed (IUCN, 1987; Griffith et al., 1989; Witkowski et al., 1997; Adamski & Witkowski, 1999a; Fisher & Lindenmayer, 2000;Sudinget al., 2004; Seddon et al., 2006; Moseby et al., 2014) or relied on constant replenishment with captive-reared individuals (Young et al., 2003; Pedrono et al., 2004). The results achieved frequently did not match the initial predic- tions, for a number of reasons (Snyder et al., 1996;Fisher& Lindenmayer, 2000;Seddonet al., 2014), including legal restrictions or organizational difficulties (Kleiman et al., 1991; Caughley & Gunn, 1996; Fisher & Linderman, 2000),


P


PAWEŁ ADAMSKI (Corresponding author, adamski@iop.krakow.pl) and ADAM M. ĆMIEL (


orcid.org/0000-0002-2276-5739, orcid.org/0000-0002-2822-


655X) Institute of Nature Conservation, Polish Academy of Sciences, Mickiewicza 33, 31-120, Kraków, Poland


Received 4 June 2020. Revision requested 6 August 2020. Accepted 10 March 2021. First published online 8 February 2022.


opulation recovery programmes using captive-reared individuals make an important contribution to conser-


state, reliable estimates of population parameters such as birth and death rates and migration are required (Seddon et al., 2006), and the use of population models incorporating such parameters have been recommended (Seddon et al., 2006; Converse et al., 2013). However, population para- meters are usually difficult to estimate or require long-term study (Beissinger & Westphal, 1998; Brook et al., 2000; Adamski & Witkowski, 2007; Parlato & Armstrong, 2012; Converse et al., 2013). By definition, recovery programmes involve a threatened species or population, the abundance and habitat of which are usually restricted. This may imply a trade-off between the methodological aptness of the research and the effectiveness of conservation measures (IUCN/SSC, 2013; Moseby, 2014). The IUCN recommends that the monitoring that suc-


ceeds a population recovery programme should continue for at least as long as the programme’s duration (IUCN/ SSC, 2013). It is often difficult to act on such guidance, how- ever, as projects may aim to establish wild-captive metapo- pulations that are more or less dependent on ongoing conservation activities (Pedrono et al., 2004; Converse et al., 2013). It is important to optimize any restoration. With inver-


tebrates, for example, large numbers of captive-bred indi- viduals can be readily reared (Morton, 1983; Witkowski et al., 1997; Schultz et al., 2008; Thomas et al., 2010; Gum et al., 2011; Ćmiel et al., 2018). But the problem lies in the effectiveness of the reintroduction, measured as the popula- tion’s survivorship or growth rate (Adamski & Witkowski, 2007; Seddon et al., 2006; Gum et al., 2011; Zając et al., 2018). Most restoration programmes concern threatened species, so it is usually assumed that the abundance of the restored population will be below the habitat’s carrying ca- pacity (Converse et al., 2013). But this assumption may be


This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited. Oryx, 2022, 56(4), 564–571 © The Author(s), 2022. Published by Cambridge University Press on behalf of Fauna & Flora International doi:10.1017/S0030605321000296


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