Veränderungen im Leukozytenprofil der Dupontlerche ( Chersophilus duponti ) in Spanien und Marokko

[EN] Stress in birds has been widely studied through the measurement of heterophil-to-lymphocyte ratio (H/L ratio). In this study we aimed to assess for the first time the potential variation of stress, measured as H/L ratio, associated to geography (between-country variation) and seasonality (between seasons and within the breeding season), as well as the leukocyte profiles, in the threatened Dupont’s Lark (Chersophilus duponti), using samples from Spain and Morocco. Furthermore, we tested whether variation in H/L ratio was associated with variables such as population density, presence of blood parasites and individual body condition. We found that H/L ratio did not vary between countries, but individuals captured during the breeding season showed higher values of H/L compared to non-breeding ones. Neither male density, nor date within the breeding season had an effect on the H/L ratio. In Spain, individuals with higher body condition showed lower H/L ratio regardless of whether they were malaria-infected. In Morocco, malaria-infected individuals showed higher values of H/L ratio than the non-infected birds. Moreover, we found that our average values of H/L ratio in Morocco were within the ranges of other passerines, but not in Spain. Individuals with higher H/L ratios may be more stressed or present higher capability to face stressful situations. Although H/L ratio is a useful and relatively easy way to obtain measure of stress, the impact that the environment might have on stress and the way it is explained by H/L ratio must be addressed carefully. This study provides new insight for this species’ biology and provides useful reference information to test the status and survival of other populations.[DE] Stress bei Vögeln ist durch die Messung des Verhältnisses von Heterophilen zu T-Lymphozyten (H/L-Verhältnis) umfassend untersucht worden. In dieser Studie wollten wir zum ersten Mal die potentiellen Veränderungen des Stresses in Verbindung mit der Geografie (Unterschiede zwischen einzelnen Ländern) und der Saisonalität (zwischen den Jahreszeiten und innerhalb der Brutsaison), gemessen als H/L-Verhältnis, sowie die Leukozytenprofile bei der bedrohten Dupontlerche (Chersophilus duponti) anhand von Proben aus Spanien und Marokko bewerten. Darüber hinaus haben wir untersucht, ob das H/L-Verhältnis mit Variablen wie der Populationsdichte, dem Vorhandensein von Blutparasiten und der individuellen physischen Verfassung zusammenhängt. Wir stellten fest, dass das H/L-Verhältnis zwischen den einzelnen Ländern nicht variierte, aber die während der Brutzeit gefangenen Tiere höhere H/L-Werte aufwiesen als nicht brütende Tiere. Weder die Dichte an Männchen, noch der Zeitpunkt innerhalb der Brutsaison hatten einen Einfluss auf das H/L-Verhältnis. In Spanien wiesen Tiere mit einer besseren physischen Verfassung ein niedrigeres H/L-Verhältnis auf, unabhängig davon, ob sie mit Malaria infiziert waren. In Marokko zeigten malariainfizierte Vögel höhere Werte des H/L-Verhältnisses als nicht infizierte. Außerdem stellten wir fest, dass unsere Durchschnittswerte für das H/L-Verhältnis in Marokko innerhalb der Werte für andere Sperlingsvögel lagen, nicht aber in Spanien. Tiere mit einem höheren H/L-Verhältnis sind möglicherweise gestresster oder besser in der Lage, mit Stresssituationen umzugehen. Obwohl das H/L-Verhältnis ein nützliches und relativ einfach zu beschaffendes Maß für Stress ist, muss der eventuelle Einfluss der Umwelt auf Stress und die Möglichkeiten, diesen durch das H/L-Verhältnis zu erklären, sorgfältig untersucht werden. Diese Untersuchung bietet neue Einblicke in die Biologie dieser Art und liefert nützliche Referenzinformationen für die Bestimmung des aktuellen Status und für das Überleben anderer Populationen.Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature.This study was partially funded by the authors, the Spanish Ministry of Environment (MMA; J.J. Areces and B. Heredia), the Spanish Agency for International Cooperation (AECI), and the LIFE Ricoti (LIFE15-NAT-ES-000802), supported by the European Comisison. D.B.R. was supported by FPI-UAM fellowship from the Universidad Autónoma de Madrid (UAM), and the collaboration of the Instituto de Investigación en Recursos Cinegéticos (IREC-CSIC-UCLM). We wish to thank the Servicio de Vida Silvestre of Conselleria D’infraestructures, Territori i Medi Ambient (Generalitat Valenciana) and the Moroccan government for ringing permits and supporting our work. We thank V. Garza, A. Ramírez, R. del pozo, E. Juarez, E.L. García de la Morena, F. Suárez, M. Radi, M. Znari and M. Alouí, and the Colectivo Ornitológico Cigüeña Negra for their help during fieldtrips and arrangements. We also thank two anonymous referees whose helpful comments contributed to improve the paper. This work was approved by the Local Ethical Committee for Animal Experiments of the Autónoma University of Madrid (CEI80-1468-A229).Peer reviewe

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

In this work, we analyse factors explaining the distribution and range regression of Dupont’s lark in Spain, the only European country in which this threatened alaudid is present. Dupont’s lark is an extremely elusive and scarce species, distributed across a reduced and strongly fragmented range, showing a metapopulational structure with unknown dispersive and connective mechanisms. We used maximum entropy modelling (Maxent) on nearly 15,000 Dupont’s lark observations (1985–2015) to assess the probability of presence at a 1 km resolution across its European range. Moreover, we tested the probability of extinction by comparing pre- and post-2000 observations by means of a GLM over a subset of cells with presence-absence data. We obtained strong model fitting (AUC = 0.919), in which species occurrence was explained by low values of plant productivity (NDVI), climate (high temperature range and medium annual precipitation), land use (increasing with sclerophyllous scrubland), flat topography and human disturbance (associated with low human population density). The species also tolerates dry farming, but not other farm types or forest cover. The probability map identified two main regions known as the species’ core areas: the steppes of the Iberian System and the Ebro Valley. The North Plateau is characterised by a dispersed structure of small and very fragmented patches of suitable habitat, while a succession of discontinuous probability patches form an Eastern Corridor connecting the central core areas to the southernmost populations. Finally, the model identified small and isolated patches of high probability of presence along the eastern coastline. The species tends to occur in the best available areas but, at the same time, the model revealed a large area of suitable but unoccupied habitat. Our results correct the previous estimation of occupation area from 1,480 to 1,010.78 km2, a reduction of 26.22%. The current distribution of Dupont’s lark is almost completely covered by Important Bird Areas (IBAs), highlighting their importance for bird conservation, but only 44.89% is included in Natura 2000 Special Protection Areas (SPAs). A comparison of pre- and post-2000 periods revealed a range contraction of 44%. Probability of extinction increased with higher temperature range and lower annual precipitation, and with decreases in population density, which suggests that this species is extremely vulnerable to both climate change and rural abandonment, due to its dependence on traditional grazing. These results suggest the need for a re-evaluation of the conservation status of Dupont’s lark in Spain. They urge the preservation of not only current extant populations, but also the unoccupied suitable areas that could be critical for metapopulation structure, and the development of policies addressing the preservation of traditional grazingData used in this paper come from different projects, in particular the II National Census (2004-2006), granted by the Spanish Ministry of Environment; and the Dupont’s Lark Monitoring Program in Medinaceli Region, funded by Fundación Patrimonio Natural de Castilla y León. This is a contribution to the Excellence Network Remedinal 3CM (S2013/MAE-2719), supported by Comunidad de Madrid, and to the projects “Criteria for the management and conservation of the Spanish population of Dupont’s Lark, supported by Fundación Biodiversidad, of the Ministry of Agriculture, Food and Environment; LIFE Ricotí (LIFE15-NAT-ES-000802), supported by the European Commission; and BBVA-Dron Ricoti, funded by the BBVA Foundation. INECO provided support in the form of salary for author JHZ, but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific role of this author is articulated in the ‘author contributions’ sectio

Responses of bird communities to habitat structure along an aridity gradient in the steppes north of the Sahara

We explored the influence of habitat structure on bird density and species richness in the poorly known bird communities in the steppes of Eastern Morocco, along a 200 km long N–S gradient of increasing aridity. The birds were surveyed, and habitat structure was measured in 44 transects regularly distributed along the gradient and during the winter and spring seasons in two consecutive years. After applying a principal component analysis (PCA), five axes were identified, including one related to the latitude–altitude–soil-type gradient and another describing the development of herbaceous vegetation. Generalized linear models were used to explore the relations between bird density and species richness with PCA axes in each season, considering both the entire community and groups of granivorous, insectivorous, and mixed-diet species. More than 90% of the birds were year-round residents, with larks dominating the community in both seasons. We conclude that a distinct multifactorial response can be identified for each functional group of species. In the winter, the community is mainly affected by the structure of the habitat, while aridity (and its assumed relation to primary production) is less influential. In the spring, habitat structure continues to have the greatest explanatory power, but location along the aridity gradient becomes more relevant. These findings reveal the interaction of the negative effects of climatic and anthropogenic changes in the habitat available to these bird communities, with a greater impact expected on birds with diets that include seeds, as well as a general shift of optimal breeding conditions toward more northerly latitudes.Instituto de Investigación en Recursos CinegéticosUniversidad Autónoma de MadridDepto. de Biodiversidad, Ecología y EvoluciónFac. de Ciencias BiológicasTRUEpubPagado por el auto

Leukocyte profile variation in Dupont’s Lark (Chersophilus duponti) in Spain and Morocco

Stress in birds has been widely studied through the measurement of heterophil-to-lymphocyte ratio (H/L ratio). In this study we aimed to assess for the first time the potential variation of stress, measured as H/L ratio, associated to geography (between-country variation) and seasonality (between seasons and within the breeding season), as well as the leukocyte profiles, in the threatened Dupont’s Lark (Chersophilus duponti), using samples from Spain and Morocco. Furthermore, we tested whether variation in H/L ratio was associated with variables such as population density, presence of blood parasites and individual body condition. We found that H/L ratio did not vary between countries, but individuals captured during the breeding season showed higher values of H/L compared to non-breeding ones. Neither male density, nor date within the breeding season had an effect on the H/L ratio. In Spain, individuals with higher body condition showed lower H/L ratio regardless of whether they were malaria-infected. In Morocco, malaria-infected individuals showed higher values of H/L ratio than the non-infected birds. Moreover, we found that our average values of H/L ratio in Morocco were within the ranges of other passerines, but not in Spain. Individuals with higher H/L ratios may be more stressed or present higher capability to face stressful situations. Although H/L ratio is a useful and relatively easy way to obtain measure of stress, the impact that the environment might have on stress and the way it is explained by H/L ratio must be addressed carefully. This study provides new insight for this species’ biology and provides useful reference information to test the status and survival of other populations.This study was partially funded by the authors, the Spanish Ministry of Environment (MMA; J.J. Areces and B. Heredia), the Spanish Agency for International Cooperation (AECI), and the LIFE Ricoti (LIFE15-NAT-ES-000802), supported by the European Comisison. D.B.R. was supported by FPI-UAM fellowship from the Universidad Autónoma de Madrid (UAM), and the collaboration of the Instituto de Investigación en Recursos Cinegéticos (IREC-CSIC-UCLM). We wish to thank the Servicio de Vida Silvestre of Conselleria D’infraestructures, Territori i Medi Ambient (Generalitat Valenciana) and the Moroccan government for ringing permits and supporting our work. Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature

Recent Changes in Genetic Diversity, Structure, and Gene Flow in a Passerine Experiencing a Rapid Population Decline, the Dupont’s Lark (Chersophilus duponti)

Monitoring temporal dynamics in genetic diversity is of great importance for conservation, especially for threatened species that are suffering a rapid population decline and increased fragmentation. Here, we investigate temporal variation in genetic diversity, structure, and gene flow in the Dupont’s lark (Chersophilus duponti) across most of its range. This species shows increasing levels of population fragmentation, substantial population declines, and severe range contraction, so temporal losses of genetic diversity, increasing differentiation, and decreasing gene flow are expected when comparing present day data with previous situations. To address this, we resampled sites (nine regions in two countries) after 12–15 years (five-to-seven generations) and assessed changes in genetic parameters using 11 microsatellite markers. We found no substantial loss in genetic diversity over time at the species level, but we detected considerable variation among regions in the amount of allelic diversity and heterozygosity lost over time. Temporal variation in allele frequencies (common, rare, and private alleles), and changes in genetic differentiation and gene flow over time suggest a major role of connectivity for the stability of the overall metapopulation. Our results agree with the hypothesis that connectivity rescues genetic diversity via immigration and gene flow. However, evidence of recent genetic bottleneck and the substantial changes detected in some regions are clear signs of genetic erosion and may be signalling a rapid decline of the populations. Urgent actions must be carried out to stop and reverse human impacts on this threatened lark and its habitat.This study was partially funded by the Spanish Agency for International Cooperation (AECI; C/3868/05), and the LIFE Ricoti (LIFE15-NAT-ES-000802) and LIFE Connect Ricoti (LIFE20-NAT-ES-000133) projects, supported by the European Commission. D.B.R. was supported by the FPI-UAM fellowship from the Universidad Autónoma de Madrid (UAM). The Instituto de Investigación en Recursos Cinegéticos, IREC (CSIC-UCLM-JCCM), provided vehicles for the Moroccan expeditions and the laboratory for DNA analysis. This is a contribution to the REMEDINAL-TE Network (ES2018-EMT-4338)

Recent Changes in Genetic Diversity, Structure, and Gene Flow in a Passerine Experiencing a Rapid Population Decline, the Dupont’s Lark (Chersophilus duponti)

Monitoring temporal dynamics in genetic diversity is of great importance for conservation, especially for threatened species that are suffering a rapid population decline and increased fragmentation. Here, we investigate temporal variation in genetic diversity, structure, and gene flow in the Dupont’s lark (Chersophilus duponti) across most of its range. This species shows increasing levels of population fragmentation, substantial population declines, and severe range contraction, so temporal losses of genetic diversity, increasing differentiation, and decreasing gene flow are expected when comparing present day data with previous situations. To address this, we resampled sites (nine regions in two countries) after 12–15 years (five-to-seven generations) and assessed changes in genetic parameters using 11 microsatellite markers. We found no substantial loss in genetic diversity over time at the species level, but we detected considerable variation among regions in the amount of allelic diversity and heterozygosity lost over time. Temporal variation in allele frequencies (common, rare, and private alleles), and changes in genetic differentiation and gene flow over time suggest a major role of connectivity for the stability of the overall metapopulation. Our results agree with the hypothesis that connectivity rescues genetic diversity via immigration and gene flow. However, evidence of recent genetic bottleneck and the substantial changes detected in some regions are clear signs of genetic erosion and may be signalling a rapid decline of the populations. Urgent actions must be carried out to stop and reverse human impacts on this threatened lark and its habitat.This study was partially funded by the Spanish Agency for International Cooperation (AECI; C/3868/05), and the LIFE Ricoti (LIFE15-NAT-ES-000802) and LIFE Connect Ricoti (LIFE20-NAT-ES-000133) projects, supported by the European Commission. D.B.R. was supported by the FPI-UAM fellowship from the Universidad Autónoma de Madrid (UAM). The Instituto de Investigación en Recursos Cinegéticos, IREC (CSIC-UCLM-JCCM), provided vehicles for the Moroccan expeditions and the laboratory for DNA analysis. This is a contribution to the REMEDINAL-TE Network (ES2018-EMT-4338)