Challenges for incorporating long‐term baselines into biodiversity restoration: A case study of the Dalmatian Pelican (Pelecanus crispus) in Britain

Abstract

Species reintroductions are a core component of conservation but require critical assessment of past baselines. The Dalmatian Pelican Pelecanus crispus formerly occurred in Britain during the Holocene and there is interest in its possible reintroduction, but its regional extinction dynamics remain poorly understood. Pelican bones are known from subfossil and zooarchaeological contexts at 11 British Holocene sites in three regions (East Anglian Fens, Somerset Levels and Moors, Humber Valley). Dalmatian Pelican is positively identified from four of these sites, with other specimens only identified to genus level. Pelican populations were probably only present periodically in Britain during intervals of suitable climate and available habitat: there is little evidence for pelicans before the Bronze Age, and most sites are known or inferred to be Iron Age. There is a suggested Medieval specimen but no secure evidence of pelican presence after the Roman period. However, no specimens are directly dated, with age estimation reliant upon indirect dates or inference. Climatic niche modelling indicates that southern Britain was the northwestern limit of pelican climate tolerance under postglacial conditions, and pelicans may have been unable to persist regionally until the mid-or late Holocene. Considerable pelican breeding and foraging habitat might have existed until the Medieval period, but availability of suitable habitat fluctuated throughout the Holocene. Probabilistic analysis suggests possible mean extinction date estimates between AD 589 and AD 1587, highlighting uncertainty associated with indirect data, and hindering our ability to correlate pelican disappearance with putative extinction drivers (overexploitation, human modification of wetlands, or non-anthropogenic environmental changes). Improving our understanding of conditions associated with past pelican occurrence is essential for potential reintroduction decision-making, and direct dating of bones from all sites is needed to establish a secure chronological framework for correlating pelican presence and disappearance with regional landscape change. This review provides a robust framework for how to integrate past environmental baselines into conservation decisionmaking and reintroduction feasibility assessments.

Understanding local knowledge and attitudes toward potential reintroduction of a former British wetland bird

“…Overall, few respondents were aware of the Dalmatian pelican's status as a former native British species; this is unsurprising, given that pelicans probably became extinct in Britain over a thousand years ago (Crees et al, 2023), and is possibly the reason they were slightly less liked than most locally occurring waterbirds. However, pelicans were generally well-recognised and liked by respondents in our study, who were also generally supportive of the possibility of pelican reintroduction and associated habitat restoration.…”

“…conservation awareness, Dalmatian pelican, public opinion, questionnaire survey, reintroduction, translocation, wetland restoration two largest freshwater wetland systems, the Somerset Levels and East Anglian Fens (Crees et al, 2023;Yalden & Albarella, 2009). It probably became extinct in Britain between one and two millennia ago, due to a combination of wetland drainage and hunting and disturbance from growing human populations (Crees et al, 2023;Yalden & Albarella, 2009) (Figure 1). Dalmatian pelicans are now restricted to southeast Europe and Asia, and are listed as Near Threatened by IUCN (Catsadorakis & Portolou, 2018).…”

“…In Britain, there has been recent discussion about the possibility of reintroducing the Dalmatian pelican Pelecanus crispus to wetland landscapes (Macdonald, 2019). This species is recorded in Britain's subfossil and zooarchaeological records during the Bronze Age, Iron Age, Roman Era and possibly Medieval Era, with former breeding populations documented from Britain's two largest freshwater wetland systems, the Somerset Levels and East Anglian Fens (Crees et al, 2023; Yalden & Albarella, 2009). It probably became extinct in Britain between one and two millennia ago, due to a combination of wetland drainage and hunting and disturbance from growing human populations (Crees et al, 2023; Yalden & Albarella, 2009) (Figure 1).…”

“…This species is recorded in Britain's subfossil and zooarchaeological records during the Bronze Age, Iron Age, Roman Era and possibly Medieval Era, with former breeding populations documented from Britain's two largest freshwater wetland systems, the Somerset Levels and East Anglian Fens (Crees et al, 2023; Yalden & Albarella, 2009). It probably became extinct in Britain between one and two millennia ago, due to a combination of wetland drainage and hunting and disturbance from growing human populations (Crees et al, 2023; Yalden & Albarella, 2009) (Figure 1). Dalmatian pelicans are now restricted to southeast Europe and Asia, and are listed as Near Threatened by IUCN (Catsadorakis & Portolou, 2018).…”

“…The reintroduction is primarily being considered with a goal to re‐establish a viable pelican population and restore past wetland bird diversity, but it is likely that wider wetland restoration would also be necessary to provide suitable pelican nesting and feeding habitats, with pelican reintroduction thus having a wider role for restoring wetland ecosystem functions and processes (Macdonald, 2019; Yalden & Albarella, 2009). Any such reintroduction would require considerable research to understand the ecological conditions and human‐environmental interactions associated with past pelican occurrence and disappearance, the suitability of existing British freshwater wetlands to support pelicans, and potential landscape restoration targets required to maintain viable populations (Crees et al, 2023). However, reintroduction within the densely populated British landscape must also assess social feasibility (IUCN/SSC, 2013), including assessing and accommodating community attitudes, awareness and acceptance toward proposed pelican arrival and associated habitat management, and the extent to which reintroduction might be appropriate or not in light of these factors (Dando et al, 2022).…”