European population trends and current conservation status of an endangered steppe-bird species: the Dupont’s lark Chersophilus duponti

Abstract

BackgroundSteppe-birds face drastic population declines throughout Europe. The Dupont’s lark Chersophilus duponti is an endangered steppe-bird species whose European distribution is restricted to Spain. This scarce passerine bird could be considered an ‘umbrella species’, since its population trends may reveal the conservation status of shrub-steppes. However, trends for the Spanish, and thus European, population of Dupont’s lark are unknown. In this work, we evaluated Dupont’s lark population trends in Europe employing the most recent and largest compiled database to date (92 populations over 12 years). In addition, we assessed the species threat category according to current applicable criteria (approved in March 2017) in the Spanish catalogue of threatened species (SCTS), which have never been applied to the Dupont’s lark nor to any other Spanish species. Finally, we compared the resulting threat categories with the current conservation status at European, national and regional levels.MethodsWe fitted switching linear trend models (software TRIM—Trends and Indices for Monitoring data) to evaluate population trends at national and regional scale (i.e. per Autonomous Community) during the period 2004–2015. In addition, the average finite annual rate of change () obtained from the TRIM analysis was employed to estimate the percentage of population size change in a 10-year period. A threat category was assigned following A1 and A2 criteria applicable in the SCTS.ResultsTrends showed an overall 3.9% annual decline rate for the Spanish population (moderate decline, following TRIM). Regional analyses showed high inter-regional variability. We forecasted a 32.8% average decline over the next 10 years. According to these results, the species should be listed as ‘Vulnerable’ at a national scale (SCTS). At the regional level, the conservation status of the species is of particular concern in Andalusia and Castile-Leon, where the species qualifies for listing as ‘Endangered’.DiscussionOur results highlight the concerning conservation status of the European Dupont’s lark population, undergoing a 3.9% annual decline rate. Under this scenario, the implementation of a wide-ranging conservation plan is urgently needed and is vital to ensuring the conservation of this steppe-bird species. The role of administrations in matters of nature protection and the cataloguing of endangered species is crucial to reverse declining population trends of this and other endangered taxa.

Factors affecting Dupont´s lark distribution and range regression in Spain

“…The steppes of the Iberian Mountains (74% of the population) and the Ebro Valley (18%) are the main nuclei, followed by the North Plateau, La Mancha and Southeast regions [14, 15]. This distribution results in a metapopulational structure in which the majority of the populations have experienced a negative trend over the last years [15–18].…”

“…The main threats to the species seem to be related to its small and fragmented distribution, which makes Dupont’s lark highly vulnerable to alterations, principally, habitat loss and fragmentation [9, 27, 29]. The last population size estimation situates the entire European population at 2,200–2,800 pairs [9], which may be currently lower considering the negative trends revealed in a recent study estimated at an average annual reduction of 3.9% during the period 2004–2015 [18]. Moreover, the Spanish population suffers from a high degree of fragmentation and isolation, with gene flow being virtually absent [30] and with a high risk of extinction in the smallest and most isolated nuclei [31].…”

Assessment of cue counting for estimating bird density using passive acoustic monitoring: recommendations for estimating a reliable cue rate

“…For example, the relationship between recorded vocal activity rate and Dupont's Lark abundance around recorders shows a logarithmic curve (Pérez-Granados et al 2019b), which suggests that the effectiveness of cue counting for estimating Dupont's Lark abundance may be decreased when applied at high densities. Nonetheless, the Dupont's Lark is a threatened species (Gómez-Catasús et al 2018), listed as "Vulnerable" in Europe by the International Union for the Conservation of Nature (BirdLife International 2015). Therefore, the species is usually distributed at low densities (mean of 0.30 males/10 ha in Spain; Suárez 2010), and cue counting may be a good approach to provide a reliable range of males around recorders because their density usually ranges between one and three (as in the present study).…”

Hierarchical habitat-use by an endangered steppe bird in fragmented landscapes is associated with large connected patches and high food availability

“…11 will be intensively used by Dupont’s lark. The obtained results may contribute to improve the knowledge of the mechanisms determining the distribution pattern of Dupont’s lark, indispensable to establish conservation measures that curb the overall decline undergone by this endangered species 21 . In synthesis, we aim to expand the understanding of factors driving habitat use patterns in species inhabiting fragmented landscapes and provide a useful approach to address future studies focused on hierarchical processes or patterns in ecology.…”