Effects of habitat structure on breeding success of Grey Partridges (Perdix perdix)

Sarah Sophia Mayer

Diplomová práce

Abstract:

The loss of suitable habitats due to agricultural intensification is one of the main reasons why farmland birds, including Grey Partridges (Perdix perdix), have been declining rapidly over the last 50 years. This is why this thesis analyses the supporting and hindering effects of habitat structures on the breeding success of Grey Partridges in their areas of occurrence during the pre-breeding/breeding and post-breeding period. Ornithological observation data from 01/2012 to 12/2021 within the Czech Republic were downloaded from the public database “Avif”, and land cover data from the geodatabase “CORINE Land Cover 2018”. Grey Partridge pairs as well as corresponding family coveys were filtered from the data based on date and group size, two buffer scales (200 m and 1000 m) representing the two examined areas of occurrence (further on home ranges) were drawn around the location of the pairs in QGIS, and habitat variables (habitat proportions, diversity, length of linear features) within these home ranges were calculated. Then, the breeding success (0/1 – family covey was max. 1000 m from an observed pair earlier) was set as the response variable in two generalized linear mixed-effect models whose predictors were the habitat variables, except for the dominant category (arable land). In the pre-breeding/breeding home range (200 m buffer radius), both natural and managed grasslands, as well as linear, herbaceous structures along non-forest edges and settlements have a positive effect on the probability of a successful breeding of Grey Partridges, reflecting the importance of a concealed nesting site. The breeding success in the post-breeding home range (1000 m buffer radius) is promoted by a diverse landscape with natural grassland patches, offering good foraging grounds with a variety of insects which is essential for the chick survival. Simultaneously, habitat structures that represent a good living space for predators of Grey Partridges (forest edges, other productive areas (= vineyards and orchards)) decrease the probability of breeding success. The negative effect of habitat diversity in the pre-breeding/breeding home range as well as the one of other productive areas implies an ecological trap in the remaining unmanaged areas and potential alternative habitats. Therefore, the overall breeding success of Grey Partridges depends on a heterogenous landscape with a network of natural grassland patches as well as broadly based linear, herbaceous structures.

Keywords

breeding success, habitat structure, diversity, conservation, home range, farmland, Perdix perdix, unmanaged area

Jazyk práce: angličtina

Datum vytvoření / odevzdání či podání práce: 2. 4. 2023

Obhajoba závěrečné práce

• Obhajoba proběhla 17. 5. 2023
• Vedoucí: prof. Dr. Mgr. Miroslav Šálek
• Oponent: Jaroslav Cepák, externi

Česká zemědělská univerzita v Praze

Fakulta životního prostředí

Magisterský studijní program:
Nature Conservation