Andean bird responses to human disturbances along an elevational gradient

Montaño‐Centellas, Flavia; Garitano-Zavala, Álvaro

doi:10.1016/j.actao.2015.05.003

Cited by 17 publications

(9 citation statements)

References 42 publications

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“…Both species are common residents in the Wet Tropical Andes [106,108,110,111] and have been rarely recorded in Chile [112–116]. Our results support those of Montaño-Centellas and Garitano-Zavala [36], who suggest that ornamental and other cultivated plants may provide foraging habitat for nectarivorous birds in the Wet Tropical Andes. This may also occur in the Dry Tropical Andes.…”

Section: Discussionsupporting

confidence: 85%

“…In the Southern Alps, the peak of bird richness at mid-elevations was attributed to optimal climatic conditions, environmental heterogeneity and man-made habitats [54]. By contrast, in the Andean forests of Bolivia, bird diversity decreased with elevation and the presence of human settlements [36]. Kessler et al [37] showed that bird diversity was favored by the presence of old-growth forest remnants at intermediate elevations.…”

Section: Discussionmentioning

confidence: 99%

“…Studies conducted on birds along elevational gradients in the Wet Tropical Andes (Peru, Colombia and Bolivia) have shown a decline in species richness with elevation, due to a decrease in temperature and vegetation cover, and proximity to human settlements [15,33–36]. By contrast, Kessler et al [37], found a unimodal pattern relationship between richness and elevation in the forests of the Bolivian Andes, with a peak in bird species richness associated with the presence of old-growth forests at intermediate elevations (2700–3150 masl).…”

Section: Introductionmentioning

confidence: 99%

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Bird diversity along elevational gradients in the Dry Tropical Andes of northern Chile: The potential role of Aymara indigenous traditional agriculture

et al. 2018

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Understanding diversity patterns along environmental gradients lies at the heart of community ecology and conservation. Previous studies have found variation in bird diversity and density along “natural” elevational gradients in the Tropical Andes Hotspot. However, there is still a lack of knowledge about how bird communities respond to traditional land-use patterns, in association with other multiple drivers, along elevations. In the present study, we investigated biotic, abiotic and anthropogenic sources of variation associated with bird species diversity, density and turnover along a 3000-m elevational gradient, in southern limit of the Tropical Andes Hotspot, northern Chile. Over four seasons, we conducted 472 bird point count surveys and established 118 plots distributed across the Desert, Pre-Puna, Puna and High-Andean belts, where biotic, abiotic and anthropogenic factors were measured. We used mixed-effects models to estimate alpha diversity and multinomial Poisson mixture models to estimate species density, accounting for detectability. Species diversity and density increased until 3300 masl and then declined. This type of elevational pattern is characteristic of dry-based mountains, where environmental conditions are suitable at mid-elevations. Habitats shaped by traditional Aymara indigenous agriculture, associated with relatively high vegetation heterogeneity, hosted the highest values of bird diversity and density. Species turnover was structured by habitat type, while elevational ranges of most species were restricted to three relatively discrete assemblages that replaced each other along the gradient. Our study revealed a hump-shaped relationship between elevation and bird diversity and density in the Dry Tropical Andes Biodiversity Hotspot, supporting a diversity pattern characteristic of dry-based mountains of the world. Traditional Aymara agriculture may have constructed ecological niches for biodiversity at mid-elevations, enhancing vegetation heterogeneity, thus providing resources for resident and rare species. Increasing loss of traditional land-use may present a threat to the bird community in the Tropical Andes Hotspot.

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Section: Discussionsupporting

confidence: 85%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Bird diversity along elevational gradients in the Dry Tropical Andes of northern Chile: The potential role of Aymara indigenous traditional agriculture

et al. 2018

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“…The landscape along the gradient is dominated by evergreen humid montane and cloud forests, with steep slopes and deep valleys (Ribera , Sevilla Callejo ). The extreme topography in the study region prevents human settlements, largely reducing the impact of anthropogenic effects on community responses (Montaño‐Centellas and Garitano‐Zavala ). There is one small village (~10 families) at 1950 m along the gradient with small orchards scattered nearby the houses.…”

Section: Methodsmentioning

confidence: 99%

Interaction networks of avian mixed‐species flocks along elevation in the tropical Andes

Montaño‐Centellas

2020

Ecography

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Ecological communities are comprised of species that interact with each other and those interactions ultimately generate community structure. Network theory provides a useful framework to study communities, by simultaneously considering species composition and the interactions among species. In this study, I use mixed-species flocks as model systems to gain insights on community and network structure. Specifically, I use co-occurrence network analyses to explore if avian mixed-species flocks change in richness and composition and/or in network structure and pair-wise associations, across elevations in the tropical Andes of Bolivia. Networks of flocking species changed both in composition and in the frequency and realization of pair-wise interactions across elevations, but changes in pair-wise associations explained most of network turnover along elevation. Pair-wise interactions changed rapidly, with shared species changing in position and importance within the network. Network dissimilarity was mostly explained by changes in the nature of associations rather than by differences in composition. Altogether, results show that montane mixed-species flocks are composed of loosely connected species and that most species have the potential of switching associations, often increasing in association strength at high elevations (up to 3150 m). Networks increased in connectivity and cohesion with elevation; flocks in lower elevations had more connections and these were less even. Above 3150 m a.s.l., there was rapid decay suggesting that flocks above this critical point are less connected and cohesive. This study exemplifies how combining community, network and pair-wise analyses can provide a more holistic view on the responses of species and assemblages to environmental gradients.

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“…at lower elevations, are more likely to be disturbed (Montano-Centellas and Garitano-Zavala 2015). Avifaunal responses to human disturbances may thus be confounded by correlated changes in elevation, given that avian species richness and composition change along elevational gradients due to associated natural changes in habitat conditions (Terborgh 1977;Jankowski et al 2009Jankowski et al , 2013Montaño-Centellas and Garitano-Zavala 2015;Hui et al 2018). Despite the prevalent interaction of elevation and disturbance gradients in forests, few studies have aimed to separate their respective effects on bird communities (Montano-Centellas and Garitano-Zavala 2015).…”

Section: Introductionmentioning

confidence: 99%

Harvesting of forest products and implications for Afrotemperate bird communities in a montane forest of the Eastern Cape, South Africa

Leaver

Carstens²,

Cherry

2019

For. Ecosyst.

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Background: Harvesting of forest products is a widespread driver of disturbance in developing nations, where policies are increasingly aimed at managing natural forests for sustainable use. There is thus need for research aimed at understanding the impact of resource use on forest habitats and concomitant effects on biodiversity. Afromontane forests in the Eastern Cape, South Africa are harvested informally for poles and medicinal bark and occur along elevational gradients of 800-1600 m above sea level. Patterns of spatial diversity and human disturbance are expected to be affected by elevation. Furthermore, species' responses to disturbance are expected to vary depending on their level of habitat specialisation. Understanding harvest impacts on forest biodiversity thus requires disentangling the separate effects of elevation and disturbance, and considering forest-specialist and forest-generalist species separately. This study comprises two components. First, harvest activities, resultant harvestmediated habitat heterogeneity, and avifaunal species richness, composition and beta-diversity were compared across two elevational zones in a harvested forest. Second, the role of harvest-mediated habitat heterogeneity in driving patterns of avifaunal diversity were assessed, while controlling for elevation, and considering forest-specialist and forest-generalist species separately. Results: Harvest rates were higher, and activities more varied in the lower elevation zone, with significant impacts of harvesting on habitat features resulting in higher harvest-mediated habitat heterogeneity at lower elevations. Harvest-mediated increases in habitat heterogeneity positively affected forest-generalist species richness, while forest-specialist richness was negatively affected. While species composition of both groups differed across elevational zones, variation in harvest-mediated habitat heterogeneity did not fully account for this, suggesting that factors other than disturbance shape avifaunal communities along the elevation gradient. However, variation in harvest-mediated habitat heterogeneity accounted for the amount of beta-diversity attributed to species turnover in the forest-specialist assemblage, indicating that harvest disturbances affect the mechanisms driving beta-diversity of this group. Conclusion: Spatial patterns of avifaunal diversity are affected by elevation over a 300-m gradient. Harvesting results in increased habitat heterogeneity, which variably affects avifaunal communities at the forest-scale, with positive effects for forest generalists and negative effects for forest-specialists.

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Andean bird responses to human disturbances along an elevational gradient

Cited by 17 publications

References 42 publications

Bird diversity along elevational gradients in the Dry Tropical Andes of northern Chile: The potential role of Aymara indigenous traditional agriculture

Bird diversity along elevational gradients in the Dry Tropical Andes of northern Chile: The potential role of Aymara indigenous traditional agriculture

Interaction networks of avian mixed‐species flocks along elevation in the tropical Andes

Harvesting of forest products and implications for Afrotemperate bird communities in a montane forest of the Eastern Cape, South Africa

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