Analysis of the long-term lark population dynamics (Alaudidae, Aves) in the semi-desert in the Northwestern Caspian lowland

The dynamics of the numbers of larks inhabiting several areas differing in physical and geographical (landscape) conditions and the level of anthropogenic impact (pasture) on the natural environment is considered. Four key sites (“Akhmat”, “Zhdanov”, “Baiguzha”, and “Vetelki”) are located on the Priuzenskaya plain in the Aleksandrovo-Gaysky district of the Saratov region. The described territory is characterized by a high mosaicity of the facial structure of landscapes and, consequently, plant communities. This habitat diversity forms the structure of the communities as well as the population density of the individual lark species at the key sites surveyed. Our study of the dynamics of the numbers of species inhabiting the named key areas was carried out using calculations of logarithmic trends in the bird densities by the years of our study. In total, there were five species of larks (Alauda arvensis, Calandrella rufescens, Melanocorypha calandra, M. leucoptera, and M. yeltoniensis). As a result of our statistical processing of the obtained materials, significant differences were found in the dynamics of the numbers of individual lark species nesting in the key areas differing in landscape-ecological conditions and the level of anthropogenic load on ecosystems. In all likelihood, the dynamics of the density of the nesting lark population in the semi-desert of the Trans-Volga region is associated with both changes in the structure of habitats and, apparently, with the dynamics of the abundance of these species in the main part of their habitats, and with a number of other factors.

Influence of anthropogenic factors on the ecology of Melanocorypha calandra and Alauda arvensis in depressions of Dnipro — Molochna

The research was carried out for 3 years in the steppe biotopes of the bottoms of the Ahaymany, Barnashivsky, Green, Big Chapelsk, and Small Chapelsk depressions of the Dnipro — Molochna interfluve. Based on visual inspection and processing of space images, the degree of anthropogenic transformation of these ecosystems is analyzed. The highest percentage of plowing is characteristic of the Ahaymany depression, which occurred in the last 10 years. Among the factors that significantly affect the nesting birds of the steppe complex are also the continuous low mowing of grass (Green depression) and overgrazing of livestock — Small Chapelsk depression. The nesting density of background steppe species was determined, the highest density of Alauda arvensis in different years is characteristic of Ahaymany (245,2 pairs/km2) and Barnashivsky depression (211,2 pairs/km2), and Melanocorypha calandra — for the Big Chapelsk depression (140,1 pairs/km2). Stable is only the territory of the Big Chapelsk depression the protected regime under moderate grazing load of wild ungulates. A positive correlation was established between the values of steppe habitat area and Alauda arvensis nesting in the Ahaymany, Barnashivsky, Small Chapelsk, and Green depressions and, accordingly, a negative dependence for Melanocorypha calandra.

Modelling the Impacts of Habitat Changes on the Population Density of Eurasian Skylark (Alauda arvensis) Based on Its Landscape Preferences

The dramatic decline of the abundance of farmland bird species can be related to the level of land-use intensity or the land-cover heterogeneity of rural landscapes. Our study area in central Europe (Hungary) included 3049 skylark observation points and their 600 m buffer zones. We used a very detailed map (20 × 20 m minimum mapping unit), the Hungarian Ecosystem Basemap, as a land-cover dataset for the calculation of three landscape indices: mean patch size (MPS), mean fractal dimension (MFRACT), and Shannon diversity index (SDI) to describe the landscape structure of the study areas. Generalized linear models were used to analyze the effect of land-cover types and landscape patterns on the abundance of the Eurasian skylark (Alauda arvensis). According to our findings, the proportions of arable land, open sand steppes, closed grassland patches, and shape complexity and size characteristics of these land cover patches have a positive effect on skylark abundance, while the SDI was negatively associated with the skylark population. On the basis of the used statistical model, the abundance density (individuals/km*) of skylarks could be estimated with 37.77% absolute percentage error and 2.12 mean absolute error. We predicted the skylark population density inside the Natura 2000 Special Protected Area of Hungary which is 0–6 individuals/km* and 23746 ± 8968 skylarks. The results can be implemented for the landscape management of rural landscapes, and the method used are adaptable for the density estimation of other farmland bird species in rural landscapes. According to our findings, inside the protected areas should increase the proportion, the average size and shape complexity of arable land, salt steppes and meadows, and closed grassland land cover patches.

The general characteristics of the plowing lands birds’ population during the breeding period in Upper part of Angara region

The results of birds investigations on the most disturbed agricultural territories (plowing lands) are represented for breeding period. General indicators characterized different birds populations of plowing lands are given (density of birds populations, number of species and list of species, leaded in population of each variant of plowing lands). It is determined, that birds populations of examined lands are differ significantly. The leaders in population for many birds populations are Passer montanus (Linnaeus, 1758), Alauda arvensis (Linnaeus, 1758), Corvus corone (Linnaeus, 1758), Anthus richardi (Vieillot, 1818). The birds populations are formed for a not long period, theirs structure is defined by plowing lands sizes and degree of mosaic and the character of neighboring territories.

Fauna of birds of the flown meadows of the Pinega river (Arkhangelsk region)

Исследования, проведенные на лугах северо-востока Архангельской области в долине реки Пинеги, показали изменения фауны и численности некоторых видов птиц, связанные со значительным сокращением или прекращением сельскохозяйственного использования лугов. Следствием стало сокращение численности или отсутствие полевого жаворонка Alauda arvensis и чибиса Vanellus vanellus на некоторых лугах, ранее используемых как выпасы или сенокосы. Исчезновение дубровника Ocyris aureola не связано с прекращением сельскохозяйственного использования лугов. В то же время, в связи с зарастанием лугов древесно-кустарниковой растительностью, относительно высока численность лугового чекана Saxicola rubetra, камышовой овсянки Schoeniclus schoeniclus, пеночки-веснички Phylloscopus trochilus, чечевицы Carpodacus erythrinus, фифи Tringa glareola, большого улита Tringa nebularia и др. Studies conducted in the meadows of the northeast of the Arkhangelsk Region in the valley of the Pinega River, showed changes in the fauna and abundance of some bird species associated with a significant reduction or cessation of the agricultural use of the meadows. The effect was a reduction in the number or absence of the Skylark Alauda arvensis and the Lapwing Vanellus vanellus in some meadows previously used as pastures or hayfields. At the same time, due to the overgrowing of meadows with tree-shrub vegetation, the numbers of Whinchat Saxicola rubetra, Reed Bunting Schoeniclus schoeniclus, Willow Warbler Phylloscopus trochilus, Common Rosefinch Carpodacus erythrinus, Wood Sandpiper Tringa glareola, and Greenshank Tringa nebularia became relatively high. The disappearance of Yellow-breasted Bunting Ocyris aureola is not related to the termination of the agricultural use of the meadows.

Temporal dynamic of the phylogenetic diversity of the bird community of agricultural lands in Ukrainian steppe drylands

This study discussed the importance of the phylogenetic components in the structure of bird communities of anthropogenically transformed ecosystems. The investigation was conducted in the landscapes of the south and south-east of Ukraine in the nesting seasons 1988–2018. The bird community in the agricultural landscape was found to be presented by 10 species. The number of species was closely correlated with its phylogenetic analogue – Faith’s index. Both indices were stationary over time, as they do not show a statistically significant time trend. The two axes were extracted as a result of the DPCOA procedure and the permutation test showed their statistical significance. The axis 1 was the most sensitive to the opposite dynamics of the abundance of Coturnix coturnix and Burhinus oedicnemus on the one hand and Alauda arvensis and Melanocorypha calandra on the other. The axis 2 is the most sensitive to the opposite dynamics of Corvus monedula and Melanocorypha calandra on the one hand and Coturnix coturnix and Motacilla flava on the other. Based on phylogenetic diversity, the years can be clustered with the extraction of four relatively homogeneous phylogenetic structures of bird communities. The indicator of the initial period of dynamics (1988–1992) was Burhinus oedicnemus. Sowing or mechanical weeding may be considered as a major factor of nest destruction of Burhinus oedicnemus. The decreasing of the abundance of the trophic recourses because of agricultural activity may have caused the monotonous negative trend over time of the Burhinus oedicnemus populations. The period 1993–2003 was a transitional one, for which there were no clear indicators, as a characteristic feature of this period was the processes of bird community restructuring. The period 2004–2013 was characterized by the loss of Burhinus oedicnemus from the community and a sharp increase in the abundance of Corvus monedula. These species are distinguished by their phylogenetic specificity and are located on the periphery relative to the phylogenetic core of the community. There was growing importance in the community of such species as Alauda arvensis, Anthus campestris, and Melanocorypha calandra between 2014 and 2018. Our results also confirm the assumption that phylogenetic overdispersion is an important requirement for the stability of the bird community in anthropogenically transformed landscapes.