Bird assemblages from western Sierras Grandes and Traslasierra Valley in central Argentina: an important area for conservation of Chacoan and mountain birds

Vergara-Tabares, David L.; Schaaf, Alejandro Alberto; Verga, Ernesto G.; Quaglia, Agustín; Rojas, Tobías Nicolás; Toledo, Martín; García, Emiliano Hinojo; Peluc, Susana Inés; Diaz, Agustín Eduardo

doi:10.1007/bf03544423

Cited by 2 publications

(1 citation statement)

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“…However, this invasive shrub also has several native seed predators and pulp consumers, and it is unknown how the seed dispersal service of this species varies with elevation. Previous studies from this region indicate a decrease in frugivorous bird richness towards higher elevations (Juncosa‐Polzella et al, 2019, unpublished data; Nores et al, 1983; Vergara‐Tabares, Schaaf, et al, 2018); however, it is not known how the abundances of frugivorous guilds (seed dispersers, seed predators, and pulp consumers) vary along the elevational gradient. Our study site is an ideal system to examine the role of frugivorous birds in the spread of invasive plants along a broad elevational gradient with turnover in bird assemblages.…”

Section: Introductionmentioning

confidence: 93%

Seed dispersal of a fleshy‐fruited invasive shrub is affected by changes in the frugivorous bird assemblage along an elevational gradient

Juncosa‐Polzella,

Tecco,

Vergara‐Tabares

2023

Austral Ecology

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Seed dispersal by birds constitutes an essential mechanism for ornithochorous exotic plants to successfully invade a new system. New biotic associations with native birds might facilitate the upward spread of exotic plants from the foothills into the high mountains. However, environmental changes associated with elevation are known to drive changes in bird assemblages, and it is not clear how elevation changes impact the seed dispersal service of ornithochorous invaders. We evaluated changes in frugivorous bird assemblages of one of the exotic shrubs (Cotoneaster franchetii, Rosaceae) with the broadest elevation range among woody invaders in the Córdoba Mountains (Argentina). We quantified frugivory interactions (including absolute and proportional fruit consumption by seed dispersers, pulp consumers, and seed predators) using 4‐h observations of focal C. franchetii shrubs distributed across low‐elevation, mid‐elevation, and high‐elevation sites (700, 1100, and 1800 m a.s.l., respectively; 15 individuals per elevational band and one site per elevation). Seed disperser richness was highest at the low‐ and mid‐elevation sites (three species vs. one at the high‐elevation site), but proportional and absolute fruit consumption of C. franchetii was highest at the high‐elevation site (39.1%, 88 seeds at high‐elevation and 7.7%, 20 seeds at low‐elevation). The Chiguanco Thrush (Turdus chiguanco, Turdidae) was the only seed disperser species found at the highest elevation site. Fruit consumption by seed dispersers was positively related to their abundance and elevation. In a high mountain system, a single abundant generalist seed disperser, rather than a high richness of seed disperser species, can uphold an effective dispersal service for an invasive ornithochorous shrub. This pattern may facilitate the spread of such plants across higher elevational ranges, thereby promoting the invasion of other exotic ornithochorous plants into upper elevations.

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Section: Introductionmentioning

confidence: 93%