TY - JOUR
T1 - Woody vegetation dynamics in the tropical and subtropical Andes from 2001 to 2014
T2 - Satellite image interpretation and expert validation
AU - Aide, T. Mitchell
AU - Grau, H. Ricardo
AU - Graesser, Jordan
AU - Andrade-Nuñez, Maria Jose
AU - Aráoz, Ezequiel
AU - Barros, Ana P.
AU - Campos-Cerqueira, Marconi
AU - Chacon-Moreno, Eulogio
AU - Cuesta, Francisco
AU - Espinoza, Raul
AU - Peralvo, Manuel
AU - Polk, Molly H.
AU - Rueda, Ximena
AU - Sanchez, Adriana
AU - Young, Kenneth R.
AU - Zarbá, Lucía
AU - Zimmerer, Karl S.
N1 - Funding Information:
UN Environment Program; Global Environmental Fund; Mountain Research Initiative; National Science Foundation, Grant/Award Number: 0709598
Funding Information:
This project was funded by a grant from the Dynamics of Coupled Natural and Human Systems program of the U.S. National Science Foundation (# 0709598) to TMA and by a grant to H. Ricardo Grau and CONDESAN from the Mountain Research Initiative to fund the Andean expert workshop. The expert workshop received extra funding from the EcoAndes Project, implemented by CONDESAN and funded by the Global Environmental Fund, UN Environment, and the Swiss Agency for Development and Cooperation. We thank Martha Bonilla and three anonymous reviewers for their comments. The authors have no conflicts of interest to declare.
Publisher Copyright:
© 2019 The Authors. Global Change Biology Published by John Wiley & Sons Ltd
Copyright:
Copyright 2019 Elsevier B.V., All rights reserved.
PY - 2019/6
Y1 - 2019/6
N2 - The interactions between climate and land-use change are dictating the distribution of flora and fauna and reshuffling biotic community composition around the world. Tropical mountains are particularly sensitive because they often have a high human population density, a long history of agriculture, range-restricted species, and high-beta diversity due to a steep elevation gradient. Here we evaluated the change in distribution of woody vegetation in the tropical Andes of South America for the period 2001–2014. For the analyses we created annual land-cover/land-use maps using MODIS satellite data at 250 m pixel resolution, calculated the cover of woody vegetation (trees and shrubs) in 9,274 hexagons of 115.47 km 2 , and then determined if there was a statistically significant (p < 0.05) 14 year linear trend (positive—forest gain, negative—forest loss) within each hexagon. Of the 1,308 hexagons with significant trends, 36.6% (n = 479) lost forests and 63.4% (n = 829) gained forests. We estimated an overall net gain of ~500,000 ha in woody vegetation. Forest loss dominated the 1,000–1,499 m elevation zone and forest gain dominated above 1,500 m. The most important transitions were forest loss at lower elevations for pastures and croplands, forest gain in abandoned pastures and cropland in mid-elevation areas, and shrub encroachment into highland grasslands. Expert validation confirmed the observed trends, but some areas of apparent forest gain were associated with new shade coffee, pine, or eucalypt plantations. In addition, after controlling for elevation and country, forest gain was associated with a decline in the rural population. Although we document an overall gain in forest cover, the recent reversal of forest gains in Colombia demonstrates that these coupled natural-human systems are highly dynamic and there is an urgent need of a regional real-time land-use, biodiversity, and ecosystem services monitoring network.
AB - The interactions between climate and land-use change are dictating the distribution of flora and fauna and reshuffling biotic community composition around the world. Tropical mountains are particularly sensitive because they often have a high human population density, a long history of agriculture, range-restricted species, and high-beta diversity due to a steep elevation gradient. Here we evaluated the change in distribution of woody vegetation in the tropical Andes of South America for the period 2001–2014. For the analyses we created annual land-cover/land-use maps using MODIS satellite data at 250 m pixel resolution, calculated the cover of woody vegetation (trees and shrubs) in 9,274 hexagons of 115.47 km 2 , and then determined if there was a statistically significant (p < 0.05) 14 year linear trend (positive—forest gain, negative—forest loss) within each hexagon. Of the 1,308 hexagons with significant trends, 36.6% (n = 479) lost forests and 63.4% (n = 829) gained forests. We estimated an overall net gain of ~500,000 ha in woody vegetation. Forest loss dominated the 1,000–1,499 m elevation zone and forest gain dominated above 1,500 m. The most important transitions were forest loss at lower elevations for pastures and croplands, forest gain in abandoned pastures and cropland in mid-elevation areas, and shrub encroachment into highland grasslands. Expert validation confirmed the observed trends, but some areas of apparent forest gain were associated with new shade coffee, pine, or eucalypt plantations. In addition, after controlling for elevation and country, forest gain was associated with a decline in the rural population. Although we document an overall gain in forest cover, the recent reversal of forest gains in Colombia demonstrates that these coupled natural-human systems are highly dynamic and there is an urgent need of a regional real-time land-use, biodiversity, and ecosystem services monitoring network.
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U2 - 10.1111/gcb.14618
DO - 10.1111/gcb.14618
M3 - Research Article
C2 - 30854741
AN - SCOPUS:85065473675
SN - 1354-1013
VL - 25
SP - 2112
EP - 2126
JO - Global Change Biology
JF - Global Change Biology
IS - 6
ER -
