What is an Ecotone?
An ecotone is the boundary zone where two ecosystems meet and blend — for example, where lowland rainforest transitions into cloud forest on a mountainside, or where dry forest meets wetland along a river. These zones are biologically rich because they contain species from both adjacent ecosystems plus specialists adapted to the transition.
Characteristics
- Environmental gradient: Rapid change in temperature, moisture, or elevation across a short distance.
- Species overlap: Plants and animals from both adjacent ecosystems coexist.
- Unique species: Some organisms are specialized for ecotone conditions.
- Sensitivity: Ecotones are among the first places to show effects of climate change.
Costa Rican Ecotones
Elevation Transitions
Costa Rica's dramatic topography creates sharp ecotones:
- Lowland to premontane (700–1,200 m): Transition between tropical wet forest and lower montane forest.
- Premontane to montane (1,500–2,500 m): Cloud forest begins; epiphyte load dramatically increases.
- Montane to páramo (3,000+ m): Treeline gives way to alpine grassland on the highest peaks.
Habitat Transitions
- Forest to mangrove: Coastal ecotones where terrestrial and marine ecosystems mix.
- Dry forest to riparian gallery: Lush green corridors through seasonal brown landscapes.
- Forest to pasture: Human-created ecotones — the most common in modern Costa Rica.
Why It Matters
- Biodiversity hotspots: Ecotones support high species richness from overlapping communities.
- Climate indicators: Ecotone shifts signal changing conditions (e.g., treeline migration upslope).
- Conservation: Protecting ecotones preserves connectivity between ecosystems.