Altitudinal distribution and niche partitioning of two Redstart species in Monteverde (Parulidae), May 2009

Alternative Title

Distribución de la altitud y la partición de nicho de dos especies de Reinitas (Parulidae) en Monteverde

Creator

Brad Nitta

Files

Publication Date

May 2009

Abstract

Global climate change is affecting habitat and species interactions globally (Sekerciouglu et al. 2008), including tropical montane regions (Pounds et al. 1999, Holmes 2000, Pounds et al. 2006). In Monteverde, Costa Rica, two species of warblers, the Collared Redstart (Myioborus torquatus) and the Slate-throated Redstart (M. miniatus), are known to partition altitudinally with a sizeable sympatric zone of overlap (Shopland 1985, Mahan 1998, Adams 2003). As with other species, global warming is thought to cause changes in the altitudinal distributions of both Redstarts. Both species are expected to move upward. To avoid competitive exclusion, niche partitioning should occur in the sympatric altitudinal zone. The purpose of this study is to establish the current altitudinal distribution of both species, and compare that to previous studies. Additionally, this study attempts to identify the presence and mechanism of niche partitioning between the species in their zone of overlap. Finally, it documents changes in relative species abundance of the two species over time. Altitude data, species data, and foraging height data for the two Redstart species were collected from primary and secondary forests in the Monteverde Cloud Forest Preserve, Santa Elena Cloud Forest Preserve, and trails on Cerro Amigos; all in Monteverde, Puntarenas, Costa Rica, and with altitudinal range from 1,400 to 1,750 m. Results from this study clearly indicate increased altitudinal changes. Slate- throated Redstarts, traditionally the lower altitude species, were observed up to 1,710 m in elevation; almost 200 m higher than previous studies done in the same forests report. The Collared Redstart was observed a minimum of 10 m higher than previous observations. More importantly, the Collared Redstart is now sympatric with the Slate- throated Redstart in the entire altitudinal distribution observed. Next, relative abundance of the Collared Redstart was found to be drastically lower than previous studies. The Collared Redstart made up less than 25% of the observations in this study, whereas it has consistently composed greater than 50% of observations in past studies. Finally, foraging height was found to be a significant mechanism of niche partitioning in the sympatric altitudinal zone. In this overlap zone, below 1,602 m Slate-throated Redstarts foraged at greater heights than Collared Redstarts, while above 1,602 m the opposite trend was observed. The findings of this study support the conclusion that global climate change has affected the distribution of species in Monteverde. Because the Slate-throated Redstart is now present at altitudes previously inhabited only by the Collared Redstart, a new equilibrium of relative species abundance will be reached through effective niche partitioning, or extinction will occur most likely resulting in the loss of the Collared Redstart.

Resumen

El cambio climático global está afectando el hábitat y las interacciones de especies a nivel mundial (Sekerciouglu et al. 2008), incluyendo las regiones montañosas tropicales (Pounds et al. 1999, Holmes 2000, Pounds et al. 2006). En Monteverde, Costa Rica, dos especies de reinitas, Myioborus torquatus y M. miniatus, se sabe que tienen una partición altitudinal con una zona considerable de solapamiento simpátricas (Shopland 1985, Mahan 1998, Adams 2003). Al igual que con otras especies, se piensa que el calentamiento global causa cambios en la distribución altitudinal de las dos reinitas. Se espera que ambas especies se trasladen hacia arriba para evitar la exclusión competitiva, la partición de nicho debe ocurrir en la zona altitudinal simpátricas. El propósito de este estudio es establecer la actual distribución altitudinal de las dos especies, y compararlas con estudios anteriores. Además, este estudio trata de identificar la presencia y el mecanismo de partición de nicho entre las especies en su zona de solapamiento.

Keywords

Wood warblers, Partitioning, Habitat (Ecology), Niche (Ecology), CIEE Spring 2009

Palabras claves

Reinitas de madera, Compartimentación, Hábitat (Ecología), Nicho (Ecología), CIEE Primavera 2009

Extent

11 pages

Geographic Location

Monteverde (Puntarenas, Costa Rica)

Holding Location

Monteverde Institute

Language

English; Spanish

Media Type

Articles

Format

Digital Only

Identifier

M39-00519

Type

Book

Recommended Citation

Nitta, Brad, "Altitudinal distribution and niche partitioning of two Redstart species in Monteverde (Parulidae), May 2009" (2009). Monteverde Institute: Tropical Ecology and Conservation. 36.
https://digitalcommons.usf.edu/tropical_ecology/36