IMPROVING REINTRODUCTION SUCCESS IN LARGE CARNIVORES THROUGH INDIVIDUAL-BASED MODELLING: HOW TO REINTRODUCE EURASIAN LYNX (LYNX LYNX) TO SCOTLAND
Ovenden, T.S., Palmer, S.C.F., Travis, J.M.J., Healey, J.R., 2019. Improving reintroduction success in large carnivores through individual-based modelling: How to reintroduce Eurasian lynx (Lynx lynx) to Scotland. Biol. Conserv. 234, 140–153. doi:10.1016/j.biocon.2019.03.035
Ovenden, T.S, 2019. The potential for lynx reintroduction to Scotland Innovative modelling provides robust scientific evidence to inform decision making. doi: 10.13140/RG.2.2.35390.84806
- The Eurasian Lynx is being considered for reintroduction to Scotland having become extinct in the UK at the end of the medievil period due to habitat loss, persecution from hunting and a lack of roe deer – their favourite prey.
- We used detailed, up to date information on all of the different habitats across Scotland to generate high resolution maps of possible lynx habitat.
- We then used a sophisticated new model RangeShifter, that takes into account complex species behaviours across complex landscapes to model a reintroduction from three previously identified locations; Kielder Forest, Aberdeenshire and the Kintyre peninsula.
- We modelled each reintroduction for 100 years and averaged the results from 100 replicates.
- The Kintyre Peninsula performed best and Kielder Forest the worst, offering an 83% and 21% chance of establishing a healthy population of lynx respectively.
- Two distinct habitat networks were identified, one in the north, one in the south, separated by two major cities and road networks, making this a significant barrier to the movement of animals after release and to the colonisation of suitible habitat.
- This model can be used to inform the debate surrounding the reintroduction of lynx to Scotland and improve the chance of large carnivore reintroductions succeeding elsewhere in the world.
Globally, large carnivores have been heavily affected by habitat loss, fragmentation and persecution, sometimes resulting in local extinctions. With increasing recognition of top-down trophic cascades and complex predator-prey dynamics, reintroductions are of growing interest for restoration of ecosystem functioning. Many reintroductions have however failed, in part due to poor planning and inability to model complex eco-evolutionary processes to give reliable predictions. Using the case study of Eurasian lynx (Lynx lynx), a large predator being considered for reintroduction to Scotland, we demonstrate how an individual-based model that integrates demography with three distinct phases of dispersal (emigration, transfer and settlement) can be used to explore the relative suitability of three geographically-distant potential reintroduction sites, multi-site reintroductions and two founding population sizes. For a single-site reintroduction of 10 lynx, our simulation results show a clear hierarchy of suitability across all metrics. Reintroduction in the Kintyre Peninsula (west coast) consistently performed best, with a probability of population persistence at year 100 of 83%, and the Scottish component of Kielder Forest (southern Scotland) worst, with only a 21% chance of population persistence to year 100. Simultaneous two-site reintroduction in the Kintyre Peninsula and in Aberdeenshire (near the east coast) of 32 lynx gave a 96% persistence at 100 years. Our model was highly sensitive to survival, particularly of adults, highlighting this parameter’s importance for reintroduction success. The results strongly indicate the potential viability of Eurasian lynx reintroduction to Scotland given the current cover of suitable woodland habitat. More generally, our work demonstrates how emerging modelling approaches incorporating increased realism in representing species’ demography, ecology and dispersal can have high value for quick, inexpensive assessment of likely reintroduction success and for selection between alternative strategies.
- IBM approaches that integrate stochastic movement trajectories with population dynamics modelling across heterogeneous landscapes provide greater realism in reintroduction modelling.
- This modelling approach enables the quick and effective assessment of alternative reintroduction proposals and management scenarios.
- The contribution of this modelling approach could significantly improve the probability of reintroduction successes, especially of large carnivores.
- This case study demonstrates the suitability of existing habitat in Scotland for the reintroduction of Eurasian lynx but that appropriate site selection is key to success.
Science media coverage:
Local, national & international media:
THE PREVALENCE AND SOURCE OF PLASTIC INCORPORATED INTO NESTS OF FIVE SEABIRD SPECIES ON A SMALL OFFSHORE ISLAND
Thompson D.L., Ovenden T.S., Pennycott T., Nager R.G., 2020. The prevalence and source of plastic incorporated into nests of five seabird species on a small offshore island. Mar Pollut Bull 154:111076. doi: 10.1016/j.marpolbul.2020.111076
There is little evidence documenting the prevalence of plastic nest incorporation for different seabird species and populations, and even less detailing the source of such debris as nesting material. This study presents a baseline dataset on the presence of plastic in the nests of five seabird species on Lady Isle, Scotland using a novel and repeatable methodology for quantifying plastic incorporated into nests. Plastic was found in 24.5% to 80% of nests of all species. We analysed pellets of regurgitated material and the spatial distribution of herring gull nests containing plastic in the context of the tide and nesting habitat. Differences in the types of plastic found in pellets and nests suggests that plastic incorporated into herring gull nests was not derived at foraging sites and likely collected from the local environment. Targeted beach cleans before the breeding season could help minimise the quantity of plastic available to herring gulls.
Research on the source and quantity of plastic in seabird nests is currently rare.
- Prevalence and quantity of plastic in 5 species on an uninhabited island, SW-Scotland.
Proportion of nests with plastic was >25%, varying between species in the same site.
- Nest plastic was likely from the local environment rather than regurgitated pellets.