Land Cover Change in Colombia: Surprising Forest Recovery Trends between 2001 and 2010

<div><h3>Background</h3><p>Monitoring land change at multiple spatial scales is essential for identifying hotspots of change, and for developing and implementing policies for conserving biodiversity and habitats. In the high diversity country of Colombia, these types of analyses are difficult because there is no consistent wall-to-wall, multi-temporal dataset for land-use and land-cover change.</p> <h3>Methodology/Principal Findings</h3><p>To address this problem, we mapped annual land-use and land-cover from 2001 to 2010 in Colombia using MODIS (250 m) products coupled with reference data from high spatial resolution imagery (QuickBird) in Google Earth. We used QuickBird imagery to visually interpret percent cover of eight land cover classes used for classifier training and accuracy assessment. Based on these maps we evaluated land cover change at four spatial scales country, biome, ecoregion, and municipality. Of the 1,117 municipalities, 820 had a net gain in woody vegetation (28,092 km²) while 264 had a net loss (11,129 km²), which resulted in a net gain of 16,963 km² in woody vegetation at the national scale. Woody regrowth mainly occurred in areas previously classified as mixed woody/plantation rather than agriculture/herbaceous. The majority of this gain occurred in the Moist Forest biome, within the montane forest ecoregions, while the greatest loss of woody vegetation occurred in the Llanos and Apure-Villavicencio ecoregions.</p> <h3>Conclusions</h3><p>The unexpected forest recovery trend, particularly in the Andes, provides an opportunity to expand current protected areas and to promote habitat connectivity. Furthermore, ecoregions with intense land conversion (e.g. Northern Andean Páramo) and ecoregions under-represented in the protected area network (e.g. Llanos, Apure-Villavicencio Dry forest, and Magdalena-Urabá Moist forest ecoregions) should be considered for new protected areas.</p> </div

Absolute area of <i>woody</i> vegetation (W), <i>mixed woody/plant</i> (MWP), and <i>ag/herb</i> (AH) from 2001 to 2010 at the country, biome (B) and ecoregion (E) scales.

<p>These estimates are based on estimates from municipality-scale regression models and include all municipalities.</p

Map of the 13 ecoregions and 1117 municipalities in Colombia.

<p>Insert shows the distribution of the six biomes, and the five regions.</p

Classification accuracy assessment.

<p> <b>Biome description:</b></p>1<p>Tropical and Subtropical Moist Broadleaf Forest (Amazon basin section).</p>2<p>Tropical and Subtropical Moist Broadleaf Forest (Coastal lowlands section).</p>3<p>Tropical and Subtropical Dry Broadleaf Forest.</p>4<p>Tropical and Subtropical Grasslands, Savannas and Shrublands.</p

Areas of significant change in land cover.

<p>Transitions between A) <i>woody</i> vegetation and a<i>g/herb</i>; B) <i>mixed woody/plant</i> and <i>ag/herb</i>; C) <i>woody</i> vegetation and <i>mixed woody/plant</i> are shown. Red and blue dots represent municipalities with significant loss and gain in cover area (km²), respectively. Black ovals represent prominent clusters of land cover change. Orange and green arrows present deforestation and reforestation transitions, respectively. Land transitions (i–vi) discussed in the text.</p

A comparison of four estimates of <i>woody</i> vegetation class at the national scale.

‡<p>Data including only <i>woody</i> vegetation.</p>†<p>Data including <i>woody</i> vegetatio<i>n</i>+<i>mixed woody/plant.</i></p>‡<p>Forest cover (80 crown cover).</p>±<p>Forest cover (25 crown cover).</p><p> <b>Sources:</b></p>1<p>Cabrera E, Vargas DM, Galindo G, García MC, Ordoñez MF, et al. (2011).</p>2<p>FAO (2010) Global Forest Resources Assessment 2010.</p>3<p>Hansen M, DeFries R, Townshend JR, Carroll M, Dimiceli C, et al. (2006).</p

Mapping regions and total sample counts used in each separate Random Forest (n = 4).

<p>These include only samples filtered by the Random Forest outlier removal step (Biomes follow Olson et al. 2001).</p

Top ten municipalities with the greatest net gain (+) and net loss (−) of <i>woody</i> vegetation between 2001 and 2010.

<p>Columns show area, net change, correlation coefficient (R), <i>p-</i>value, and the percentage of change of the top ten municipalities with greatest net gain and loss between 2001 and 2010.</p

Above-ground biomass of Neotropical secondary forests database

This database is the product of the 2ndFOR collaborative research network on secondary forests. The database contains aboveground biomass data (in Mg/ha) for 1334 secondary forest plots differing in time since abandonment. The plots belong to different chonosequence studies in the Neotropics. For a description of the database, see Poorter et al. 2016. Biomass resilience of Neotropical secondary forests. Nature doi:10.1038/nature16512