Short-term impact of an extreme weather event on the threatened Dupont’s LarkChersophilus duponti

Abstract

Summary The frequency and intensity of extreme weather events represent a threat for biological diversity and are expected to increase in many regions over the following decades due to climate change. Our current knowledge about the impact of extreme weather events on the population dynamics of bird species is very limited. Here, we evaluated the impact of an extreme winter snowstorm on the abundance of 14 populations of the threatened Dupont’s Lark Chersophilus duponti, a resident bird whose European population is restricted to Spain. We found a drastic and significant population decline in the next reproductive season following the extreme weather event. During the control period (2017–2020) the species suffered an overall annual decline of 19.4% (±5.0, SE). However, the overall annual decline after the storm was 67.6% (±9.4, period 2019–2021), with a mean decline of 66.5% (±15.9) for seven populations monitored both the year before and the year after the snowstorm (period 2020–2021). The snow covered the ground for over 10 days in central and eastern Spain, which together with a subsequent extreme cold wave could have reduced the species ability to find food resources and properly thermoregulate, forcing the species to move to unknown areas. Indeed a few days after the storm, several individuals were reported in areas typically avoided. Such displacements may increase the mortality risk for dispersing individuals, besides the direct effects of the extreme cold event, such as thermal challenges to energy balance or a reduced immune function. We discuss the potential role that extreme weather events may have on the population dynamics and conservation of the species.

Range Contraction and Population Decline of the European Dupont’s Lark Population

“…That decline is not homogeneous among regions, showing a larger decrease in the peripheral regions, such as Andalucía, Comunidad Valenciana and Región de Murcia, than in the core area, i.e., the Iberian System, where populations remain more stable (see the populations extinct between periods in Figure 1). The last census carried out in the three cited regions was conducted following the snowstorm Filomena, which provoked a decrease of around 66.7% in the number of males between the year before and following Filomena [26], which may also partly explain these larger declines. In this sense, in those populations for which we do not have post-snowstorm Filomena data, the estimates of the current status of the Dupont's lark may be overestimated.…”

“…We used the same approach as [26] to estimate the population change between the two periods. The average annual population change was estimated following the formula:…”

“…40%, [24]) and a loss of genetic variability [25]. Moreover, a recent study revealed that the extreme snowstorm "Filomena", which occurred in Spain in January 2021, led to a 66.5% average decline in seven populations monitored the year before and after the snowstorm, which may have also had a great impact on the population dynamics of the species [26]. Although the declining status of the species is well described, the current population size and magnitude of the downward trend for the whole Spanish population are unknown.…”