First steps towards assessing the evolutionary history and phylogeography of a widely distributed Neotropical grassland bird (Motacillidae:Anthus correndera)

Abstract

Grasslands in southern South America are extensive ecosystems which harbor a unique biodiversity; however, studies on the evolution of their taxa are scarce. Here we studied the phylogeography and population history of the Correndera Pipit (Anthus correndera), a grassland specialist bird with a large breeding distribution in southern South America, with the goals of investigating its phylogeographic history and relate it to the historical development of South American grasslands. The mitochondrial NADH dehydrogenase subunit II gene (ND2) was sequenced in 66 individuals from 19 localities and the intron 9 of the sex-linked gene for aconitase (ACOI9) was sequenced from a subset of those individuals, including all five subspecies of A. correndera, as well as the closely related A. antarcticus. Phylogenetic analysis revealed two distinct lineages within the complex: the first (A) corresponding to Andean subspecies A. c. calcaratus and A. c. catamarcae and the second (B) including birds traditionally assigned to A. c. correndera, A. c. chilensis, A. c. grayi and some individuals of A. c. catamarcae. A. antarcticus is nested within this second lineage. These results were also supported by evidence of niche divergence for variables associated with precipitation. The oldest split between clade A and B was estimated at c. 0.37 Mya, during the middle Pleistocene. Species distribution models for the present and the Last Glacial Maximum (LGM) suggest that grassland areas in southern South America remained relatively stable, in contrast to the general view of a reduction in grassland cover in South America since the LGM. Recent divergences and low phylogeographic structure (for lowland vs. highland geographic groups, intra-population genetic variance was greater than inter-groups; e.g., for ACOI9: 95.47% and ND2: 51.51% respectively), suggest widespread gene flow between lowland populations.

From pampa to puna: Biogeography and diversification of a group of Neotropical obligate grassland birds (Anthus:Motacillidae)

“…We explicitly tested for the effects of major climatic events on the dynamics of Anthus diversification by examining different models with fixed time parameters under a shifting‐rate framework: at 5.3 Mya (Miocene–Pliocene boundary to test for effects of C4 grassland spread in South America), at 4.0 Mya (start of formation of uppermost Andean vegetation zones in older Central Andes, Pennington & Hughes, ), at 2.0 Mya (end of formation of uppermost Andean vegetation zones in young northern Andes, Pennington & Hughes, ), and at 1.8 Mya (start of Quaternary glaciations). We used a subset of the data, excluding subspecies abariensis of A. lutescens Pucheran, 1855, because of its genetic closeness to subspecies parvus and using one lowland and one highland lineage as representatives of the poorly differentiated A. correndera Vieillot, 1818 complex (Norambuena, Van Els, Muñoz‐Ramírez, & Victoriano, ). We ensured a full search of parameter space by assessing models using fixed time parameters at every 1‐million‐year interval in the tree.…”

“…We explicitly tested for the effects of major climatic events on the dynamics of Anthus diversification by examining differ- Andes, Pennington & Hughes, 2014), and at 1.8 Mya (start of Quaternary glaciations). We used a subset of the data, excluding subspecies abariensis of A. lutescens Pucheran, 1855, because of its genetic closeness to subspecies parvus and using one lowland and one highland lineage as representatives of the poorly differentiated A. correndera Vieillot, 1818 complex (Norambuena, Van Els, Muñoz-Ramírez, & Victoriano, 2018). We ensured a full search of parameter space by assessing models using fixed time parameters at every 1-million-year interval in the tree.…”

A general scenario to evaluate evolution of grassland birds in the Neotropics

“…2016), with the degree of connectivity varying with altitude and geographical location as was reported for Anthus correndera, a specialist grassland bird (Norambuena et al . 2018).…”

“…LGM) events that have differentially impacted the continent‐wide distribution as expansion following retractions or strong demographic fluctuations (Beheregaray 2008, Norambuena et al . 2018, Cabanne et al . 2019).…”

“…2019) and even favours possible hybridization areas or secondary contact zones (Norambuena et al . 2018). This process could occur in different latitudes across the Andean distribution (Fig.…”