Overview
As defined in the Convention on Biological Diversity, biodiversity is not a single layer but consists of three interrelated levels:
Genes, Species, and Ecosystems. These form a nested structure, and biodiversity cannot be maintained if any one is missing.
Theoretical Background
This three-tier model became an international consensus during the CBD drafting process in the early 1990s. Until then, conservation had tended to focus on "species," but it became widely recognized that protecting species requires their habitats (ecosystems), and species survival requires variation within populations (genes).
Detailed Explanation
1. Genetic Diversity
This refers to differences in genes within the same species. It produces variations in color, shape, patterns, and disease resistance among individuals.
- Importance: It is the source of adaptability to environmental changes (adaptive evolution). Populations with low genetic diversity (such as inbred populations) have a higher risk of extinction from new diseases or climate change.
- Example: Disease-resistance genes found in wild relatives of cultivated plants are extremely important for crop improvement.
2. Species Diversity
This refers to the abundance of species living in a given area and the evenness of their distribution. When people say "biodiversity," they often imagine this level.
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Species Richness: Simply the number of species.
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Species Evenness: Whether certain species dominate. For example, in a forest with 10 species and 100 individuals, if one species has 91 individuals and the remaining 9 species have 1 each, diversity is considered low (evaluated using Shannon Index, etc.).
3. Ecosystem Diversity
This refers to how many different environment types (habitats) exist—such as forests, grasslands, wetlands, coral reefs, and rivers—and how they function.
- Landscape Level: Having different environments adjacent to each other in a patchwork pattern (ecotones) supports many organisms. For example, dragonflies need both "aquatic habitat for larvae" and "terrestrial habitat for adults," so they require ecosystems that combine waterways and forests.
Critical Examination
Trade-offs Between Levels
Attempting to protect diversity at one level may conflict with another level.
- Example: To protect a specific rare species (species diversity), it may be necessary to clear a mature forest to create grassland (artificial modification of the ecosystem).
Bias Toward "Species-Centrism"
Current legal systems and Red Lists still operate on a "species" basis, and consideration for "genetic diversity" and "ecosystem functions" is sometimes legally insufficient. Protection of genetic resources in particular has become an international political issue, intertwined with economic interests (ABS: Access and Benefit Sharing).
What IKIMON Can Do
IKIMON's platform engages with all three of these levels.
- Visualizing Species Diversity: The main function. Mapping where different species exist.
- Understanding Ecosystem Diversity: Background information from posted data (habitat photos) and location information helps infer and record what kind of environment (wetland, woodland, etc.) a location has.
- Insights into Genetic Diversity: (In the future) By accumulating regional color and pattern differences (geographic variation) within the same species, it may be possible to provide research materials for studying the distribution of genetic variation within species.
References
- Gaston, K. J., & Spicer, J. I. (2004). Biodiversity: An Introduction. Blackwell Publishing.
- Ministry of the Environment, Japan. National Biodiversity Strategy.
