Are biological corridors helping ecosystems to adapt
to climate change in Costa Rica?
Bruno Locatelli
1
, Pablo Imbach
2
and Yves Laumonier
1
1
CIRAD-CIFOR, Bogor, Indonesia
2
CATIE, Turrialba, Costa Rica
For further information, please contact b.locatelli@cgiar.org
Introduction
As the distribution of biomes relates mainly to temperature and precipitation, it will be affected by climate change. The future distribution depends on the ability of plants to
migrate, which may be reduced by landscape fragmentation. Biological corridors have been proposed for facilitating the adaptation of ecosystems to climate change. In Costa Rica,
as protected areas are increasingly isolated, biological corridors are being progressively implemented (Figure 1).
Objective
Assessing the contribution of biological corridors (BC) to the adaptation of protected areas (PA) to climate change in Costa Rica
Methods and data
Model overview: We developed a spatial model with cellular automata, a resolution of 2
arc min (~5 km) and time steps of 10 years (from 1990 to 2050). Species can move between pixels when climate evolves, depending on their capacities and the landscape (Figure 2).
Vegetation representation: We used the Holdridge bioclimatic classification of life zones
(Figure 3). Assumption: the vegetation adapted to each life zone is composed of 5 species with different migration capacities.
Data: We used altitude and climate data from WorldClim, land use, protected areas and
corridors from CCAD & World Bank.
Model runs:
Analysis: Index of climate change impact = status of vegetation in PA in 2050, compared
to two hypothetical scenarios (index = 0 for full natural vegetation in the country, i.e. unavoidable impact; index = 1 without migration, i.e. maximum impact).
Contributions of individual corridors: difference between the impacts of climate change on PA between a scenario with all BC and a scenario with all BC but one.
Results and discussion
The enhancement of BC reduces the impacts of climate change on PA (Figure 4)
Analysis of sensitivity: results differ significantly with different climate scenarios (p<0.05) but not with different migration representations.
The PA most potentially impacted by climate change are located in the mountains and the dry northwest part of the country (results not shown).
The PA benefiting the most from BC are located in the Northwest, where PA are potentially highly impacted and poorly connected (Figure 5).
Corridors are benefiting less to PA in the southeast central mountains, because the PA are already connected.
Conclusion
Corridors play an important role in facilitating the adaptation of protected areas in Costa Rica, especially altitudinal corridors and dry area corridors. This role is clear, even when
uncertainties on climate and migration are taken into account. Climatic uncertainties have more influence on the results than uncertainties on migration processes. Several climate
scenarios should therefore be considered when planning corridors for adaptation to climate change.
Figure 4. Impact of climate change on PA
with different policies (bars represent the standard deviation of the results of the 16 runs for each policy option)
Figure 5. Contribution of individual
corridors to the adaptation of protected areas
Figure 3.
Holdridge life zones
Figure 2. Algorithm
4 migration representations
4 climate scenarios X X 3 policy options = 48 runs
Species can migrate through contiguous or non
contiguous pixels
Two sets of values for migration capacities of the 5 species (100, 250, 500, 1000 & 2000 m/yr and 50,
100, 250, 500 & 1000 m/yr) HADCM3 and CCCMA climate models A2 and B2 greenhouse gas emission scenarios
- Enhanced corridors (natural vegetation in BC) - Status quo (current vegetation in BC)
- Degraded corridors (no vegetation in BC)
Estimate 1990 Life Zone (lz1990) Estimate Current Life Zone (lzcurrent )
Controller Pixel
px
Speciessp
Create baseline: presence(px,sp)=1 if sp is adapted to lz1990
Initialize
Run
Is sp adapted to lzcurrent? No: reduce presence
Yes: Is sp already present in px? Yes: increase presence
(with upper bound: carrying capacity) No: Is sp present in neighbourhood? (radius= migrationCapacity (sp))
Yes: introduce species No: nothing Update indicators Ne xt d ec ad e
Enhanced corridors Status quo Degraded corridors
0 0.05 0.1 0.15 0.2 0.25 CC Im pa ct In de x
Figure 1. Corridors and
protected areas in Costa Rica
thorn steppe / woodland desert scrub dry forest moist
forest forestwet forestrain desert
scrub thorn
woodland very dryforest forestdry moistforest forestwet forestrain desert
desert
steppe moist
forest forestwet forestrain desert
scrub desert
dry
scrub forestmoist forestwet forestrain desert
dry
tundra tundramoist tundrawet tundrarain desert desert desert
annual precipitation (mm) 62.5 125 250 500 1000 2000 4000 8000 1600 0 0.125 0.25 0.5 1 2 4 8 16 32
potential evapotranspiration rati o humidity provinces super-humid per-humid humid sub-humid semi-arid arid perarid super-arid polar subpolar boreal warm temperate subtropical tropical cool temperate 1.5 °C 3 °C 6 °C 24 °C 12 °C latitudinal regions biotemperatur e critical temperature line alvar alpine subalpine lower montane premontane montane altitudinal belts
