Master’s Thesis

Title: Secondary syntopy in North American passerines: Multiscale analysis using the BBS dataset

Supervisor: Prof. Vladimír Remeš

Annotation

Understanding the ecological and evolutionary drivers of local co-occurrence (syntopy) among closely related species is essential for explaining biodiversity patterns. My Bachelor’s thesis, Ecology and Evolution of Secondary Sympatry in Birds, provided a theoretical foundation by exploring how ecological divergence facilitates coexistence following range overlap.

Building on this framework, my Master’s thesis focuses on the ecology and evolution of local syntopy in North American passerines using data from the North American Breeding Bird Survey (BBS), a large-scale standardized monitoring program. The central hypothesis is that local syntopy is promoted by ecological divergence, particularly in resource use, and that the influence of such predictors varies across spatial scales.

I will assess syntopy at the scale of individual point counts and entire transects, and evaluate the role of species traits in shaping these patterns. The methodological framework follows Remeš & Harmáčková (2023), which uses unbiased co-occurrence analyses to infer the drivers of syntopy.

Materials and Methods

The study uses data from the North American Breeding Bird Survey (BBS), a long-term monitoring program that records bird assemblages across ~2,900 routes annually. Each route consists of 50 point counts spaced 0.5 miles apart.

I will analyze syntopy at two spatial resolutions:

• Point scale: Individual point counts (local co-occurrence).
• Transect scale: Combined stops along each route (regional co-occurrence).

Analyses will follow the co-occurrence modeling approach of Remeš & Harmáčková (2023), integrating species traits to identify ecological predictors of coexistence. A novel aspect of this work is the multiscale analysis of syntopy across spatial resolutions.

Reference: Remeš, V. & Harmáčková, L. (2023). Resource use divergence facilitates the evolution of secondary syntopy in a continental radiation of songbirds (Meliphagoidea): Insights from unbiased co-occurrence analyses. Ecography, e06268. https://doi.org/10.1111/ecog.06268