Long‐term ecological data confirm and refine conservation assessment of critically endangered swift parrots

Abstract

Conservation assessments of threatened species are often limited by scarce data and parameter uncertainty. Predictive models, designed to incorporate this uncertainty, may be the only tool available to inform conservation assessments for data‐deficient species, but they are used surprisingly rarely for this purpose. The swift parrot Lathamus discolor is the only critically endangered bird to be listed in Australia based on population viability analysis (PVA). We aimed to evaluate the accuracy of the 2015 conservation assessment, which used sparse information, by incorporating new detailed and long‐term data. First, we updated a range of life history parameter estimates, and then we repeated the same PVA as per the original conservation assessment. This process confirmed our earlier finding that swift parrot nests were more likely to survive in places with high mature forest cover. We identify that high forest landscape integrity and abundant hollow‐bearing trees best predict nest daily survival rates. Based on the updated PVA, we predict a 92.3% population decline over three generations (11 years). This supported the predictions of the original conservation assessment, and the main benefit of the additional data was improved confidence in projections (the magnitude and direction of the population decline were similar between the original and updated PVAs). Our results demonstrate that meaningful trends can be inferred for species with imperfect information about their life history. Using predictive models like PVAs can help managers identify which life history parameters impact most on demographic trends. This information can guide targeted data collection so that ‘draft’ models can be later updated to improve certainty around population predictions.

Detection and density estimation for a cryptic species

“…Cryptic behaviour and efficacy of capture/detection can be a hindrance for accurate density estimation in these animals. We address this challenge for the sugar glider in the context of its unusual role as a threat to a critically endangered species (Owens et al , 2022, Stojanovic et al , 2014. Our literature review revealed that four decades worth of effort have not changed capture or trapping rates, with little innovation in baiting approaches.…”

Detection and density estimation for a cryptic species

“…Cryptic behaviour and efficacy of capture/detection can be a hindrance for accurate density estimation in these animals. We address this challenge for the sugar glider in the context of its unusual role as a threat to a critically endangered species (Owens et al., 2023; Stojanovic et al., 2014). Our literature review revealed that four decades worth of effort have not changed capture or trapping rates, with little innovation in baiting approaches.…”

A reference genome, mitochondrial genome and associated transcriptomes for the critically endangered swift parrot (Lathamus discolor)

“…The swift parrot is Critically Endangered (BirdLife International, 2018) due to the combined effects of logging of its important breeding habitat (Webb et al, 2019) and the impacts of an introduced predator (Heinsohn et al, 2015). Population viability analysis has shown that the already small population of only a few hundred swift parrots (Olah et al, 2021) is likely to rapidly decline over coming generations (Heinsohn et al, 2015;Owens et al, 2023) Although the species has already been subject to population genetic study (Olah et al, 2021;Stojanovic et al, 2018), there remain outstanding questions about multiple aspects of the species' genetic ecology. For example, like other parrots with small population sizes (Morrison et al, 2020), understanding the genetic basis of immune competence is critical for managing demographic impacts of disease in swift parrots (Saunders & Tzaros, 2011).…”