DOI: 10.5061/dryad.r2280gbds
title: Temporal stability in species richness but reordering in species abundances within avian assemblages of a Tropical Andes conservation hot spot

description: As the pace of environmental change increases, there is an urgent need for
 quantitative data revealing the temporal dynamics of local communities in
 tropical areas. Here we quantify the stability of avian assemblages in the
 highly threatened, but poorly studied, Andean biodiversity hot spot. We
 evaluated the temporal variation in species richness and community
 composition of local bird assemblages in three habitat types (native
 forest, introduced forest, native shrub) using a unique, relatively
 long-term data series from Cajas National Park and Mazán Reserve in the
 Southern Andes of Ecuador. We sampled birds with mist nets using a
 standardized protocol over 11 years, from 2006 to 2016. Species richness
 remained stable over time across habitats, but community composition
 changed in the native forest. In particular, we observed taxonomic
 reordering in the native forest, in which the evenness in the distribution
 of abundances of taxa decreased over time. This finding is consistent with
 other studies where species richness remained constant over time while
 community composition changed. Our study highlights the value of long-term
 studies in the tropical Andes as we show that species composition of birds
 in a montane forest is changing, consistent with global trends in
 biodiversity change.
description: This study was conducted in Cajas National Park and the adjacent
 Mazán private reserve in the high Andes of Azuay province, Ecuador Mazán
 reserve has 2700 ha (02.870° S, 79.120° W) of mostly native montane
 forest, with páramo grasslands occupying the upper ridges of the valley.
 Selective logging occurred in Mazán &gt;30 years ago, but today it is
 under strict protection that permits only limited scientific activity. In
 Cajas National Park, we worked in the U-shaped Llaviuco valley (02.840 S,
 79.160° W) at the eastern border of the park. Recreational activities
 (trekking) are common in this valley, but are limited to selected trails.
 Most of the forest in this valley was cleared for cattle ranching, but
 since its incorporation into Cajas National Park in 1996 and the removal
 of the cattle, vegetation has naturally re-established.
 Within Mazán and Llaviuco, we placed three sampling stations in
 areas with different habitat types: native montane forest (hereafter
 native forest), mixed stands of mature <i>Eucalyptus sp.</i>
 and <i>Pinus patula</i> with a native understory (hereafter
 introduced forest), and early successional vegetation (hereafter native
 shrub). The native forest was located in Mazán at an elevation of 3200 m.
 a.s.l.. Common tree species around the sampling station included
 <i>Hedyosmum cumbalense</i>, <i>Symplocos
 quitensis,</i> and <i>Myrcianthes</i> sp., with an
 understory mainly composed of <i>Miconia bracteolata</i>,
 <i>Viburnum triphyllum,</i> and <i>Oreopanax
 avicenniifolius. </i>The canopy reached 10-15 m. The introduced
 forest was also located in Mazán at 3100 m. a.s.l.. The canopy here varied
 between 15-20 m, and species common in the understory included
 <i>Rubus</i> sp. and <i>Baccharis</i> sp. The
 native shrub was located in Llaviuco Valley at an elevation of 3150 m.
 a.s.l., and is successional stage of native montane forest. Common shrub
 species were <i>Barnadesia arborea</i>,
 <i>Brachyotum</i> sp., <i>Rubus</i>
 <i>floribundus,</i> and <i>Salvia</i>
 <i>corrugata. </i>The canopy was low (&lt; 2-3 m), with
 isolated taller trees mainly along small creeks that crossed our sampling
 area. There has been little change in the structure of the vegetation in
 all habitat types over the period of this study.
 <b>Sampling Protocol</b> At each
 sampling station, we captured birds by placing 20 mist nets (12 m x 32 mm
 mesh) along edges of narrow trails (1 m aprox.) in fixed locations for two
 consecutive days (Figure 2). Nets were open from dawn to 17:00 of day 1,
 and dawn to 11:00 of day 2. All birds were uniquely banded with a numbered
 aluminum metal band to identify recaptured individuals. Birds were sampled
 three times annually from 2006 to 2016 at each sampling station. To cover
 the climatic seasonality of the study area we sampled once in the main wet
 season (within April 1<sup>st</sup> - May
 15<sup>th</sup>), once in the dry season (within July
 15<sup>th</sup> - August 15<sup>th</sup>), and
 once in the secondary rainy season (within November
 9<sup>th</sup> - December 18<sup>th</sup>). The
 total number of sampled hours varied somewhat among sampling periods
 because we did not operate nets during rainy conditions.
description: The data shown has not been corrected by sampling effort. Data
 for the Endangered species Metallura baroni has been removed, following
 guidelines of the National Park. Rare species were removed from the data
 set