Tropical alluvial forest fragmentation in the eastern lowlands of Colombia (1939-1997)

• Published in: Land degradation & development 2007-03, Vol.18 (2), p.199-208
• Main Authors: Madriñán, L.F, Etter, A, Boxall, G.D, Ortega-Rubio, A
• Format: Article
• Language: English
• Subjects: alluvial plains; anthropogenic activities; canopy; channelization; Colombia; deforestation; eastern lowlands; floodplains; habitat fragmentation; lowland forests; Meta River; rivers; soil fertility; temporal variation; tropical alluvial forests; tropical forests; vegetation cover
• ISSN: 1085-3278; 1099-145X
• DOI: 10.1002/ldr.767

Alluvial forests are under high pressure from human activities because of their value as agricultural, wildlife, timber and recreational land. Despite this, spatial patterns of alluvial forest deforestation are not well known. We studied forest alterations in a 2800 ha alluvial ecosystem using aerial photographs. During the study period (1939-1997), forests with canopy heights greater than 15m (high canopy mature forest; HCM forest) decreased by 70.4 per cent while forests with canopy heights less than 15m (low canopy mature forest; LCM forest) forests decreased by 51 per cent, producing a highly fragmented landscape. Factors responsible for forest change included human activities and river dynamics. Although most of the deforestation was related to human disturbance, almost 27 per cent of forest losses were due to channel migration of the Meta River. HCM forests were the most affected land cover since they are easily accessed, viable for logging and occurred on fertile soils, which are valuable for agriculture. LCM forests were less affected since their soil fertilities and inundation regimes were unfavourable to human uses, and thus, less prone to anthropogenic disturbances.