A Landscape Analysis of Forest Loss and Land Cover Change, 1998-2008 in the Alexander Skutch Biological Corridor, Costa Rica

Author(s): Aileen Rapson
Published: 2008
Type: M.E.S. Papers/Theses

The Alexander Skutch Biological Corridor (ASBC), located in south-central Costa Rica, links forest fragments in high elevations to forest fragments in lower elevations through two protected areas- Las Nubes Reserve and Los Cusingos Bird Sanctuary. Given that lowland rainforests are one of the most threatened ecosystems in Central America and that the ASBC traverses across three Holdridge ecological life zones, the corridor represents an area of ecological significance (Powell et al., 2000). Despite its importance, the extent and location of remaining forest areas in the corridor has not been evaluated since the late 1990s. Current information is crucial for the conservation and sustainable
management of lands within the corridor, which is the primary operating goal of the ASBC.
A 2008 analysis of forest cover and land use in the ASBC was undertaken using GIS and remotely-sensed data to assess the degree of forest loss and landscape change in the corridor since 1998. The overall goal of this study is to identify opportunities for ecological restoration in the corridor in order to strengthen the ecological integrity of the region. Interviews with corridor residents were conducted to gain insight into the socio-economic drivers of land use changes, while FRAGSTATS software was used to compute descriptive statistics of forest cover change between 1998 and 2008.
Study results reveal that the ASBC has lost 19% of its forest cover since 1998, with a corresponding decrease in average patch size from 92.14 ha in iii 1998 to 78.01 ha in 2008. Smaller forest patches in combination with a higher shape complexity have also lead to a 15% decrease in total core habitat area in the corridor. Remnant forest patches were shown to be concentrated in the
northern or southern sections of the corridor, with less than 15% of remaining forest cover located in the central regions. In contrast, connectivity between remnant forest patches increased from 39% in 1998 to 73% in 2008, suggesting that the negative effects associated with habitat isolation may have been reduced
over time.
Inconsistencies between data sources from 1998 and 2008 did not permit a direct comparison of land use changes over time. However, field observations, interview results, and external data sources indicate that shade-grown coffee plantations have decreased in the corridor at the expense of increasing pasture, sugar, and pineapple plantations.
The overall loss of forest since 1998, particularly in lowland regions, in combination with increasingly intense land uses, threatens the ability of native species populations to persist in the corridor. As such, the ecological restoration of key habitat areas is essential if the long-term protection of biodiversity is to be achieved. Areas prioritized for restoration include internal patches within large forest areas, buffering small forest patches from external stresses, and restoring vegetated corridors along major rivers in the ASBC. Market-based incentives, such as Costa Rica’s Payment for Environmental Services (PES) program, and
the efforts of community organizations will play key roles in strengthening the conservation ethic and success of the corridor.