Resource: Unique Species of Kentucky's Green River

Print Background Essay

Islands such as Madagascar and the Galapagos Islands are famous for their large numbers of endemic species, or species that exist nowhere else. However, many lesser known regions throughout the world, such as the Green River basin in Kentucky, also contain endemic species, and collectively, these regions contribute significantly to global biodiversity.

Biological diversity is important to the health and stability of ecosystems. Typically referred to as biodiversity, biological diversity encompasses the range of species within a region, genetic variation within a species, and variation between ecosystems. The larger the number of species and variation, the greater the biological diversity.

Biological diversity is important to the health and stability of ecosystems. Different species provide different cooperative community services, for example pollination, flood control, or waste decomposition. Loss of a species from an ecosystem may mean that a service is no longer provided, wreaking havoc on that system. Imagine an ecosystem without a pollinator—sexual reproduction in many plant species would stop, eliminating important food sources for many other species at the same time. A diverse ecosystem, however, is more likely to duplicate services, so the loss of one service provider is less detrimental. A diverse ecosystem is likely to be healthy and stable.

As species evolve in a niche in their environment, intricate relationships develop between organisms, species, climate and physical resources. That some species’ functions in an ecosystem are not fully understood does not diminish the importance of those species. Consider that a person may not understand the function of a particular part in an airplane motor, but removing that part is probably not a good idea! Likewise, removal of a species from an ecosystem has damaging consequences.

Endemic species gain importance when viewing Earth as one large ecosystem because the region in which they live is the only global reservoir for that genetic material. Conditions in the environment allowed the endemic species to evolve there, and then barriers, whether physical or biological, restricted mobility of that species. Therefore, if the species is lost from that region, it is lost globally.

Due to the dynamic nature of Earth's surface, evolution and extinction of species is normal. At issue is the impact humans have on the extinction of species and whether or not the resulting Earth retains enough biological diversity. When there are changes in the environment, variation within a species increases the chances that some members of that species will survive to reproduce, and a diversity of species increases the chance that some species will survive. In order to preserve global biodiversity, endemic species in all regions of the world must be conserved.

To learn more about biodiversity, check out Biodiversity in the Dzangha-Sangha Rain Forest.

To learn more about another region that has endemic species, check out Pearl and Hermes Atoll.

Print Questions for Discussion

• What makes Kentucky’s Green River special ecologically?
• Explain how not being affected by the last period of glaciation contributes to the Green River’s biodiversity.
• What evidence from the video indicates that the Green River is a healthy ecosystem?
• List at least three possible, human-related changes to the environment surrounding the Green River, and for each, predict the likely effect on the river ecosystem’s health.
• The Green River empties into the Ohio River. Suggest a reason why the orangefin darter species is endemic to the Green River and has not migrated to the Ohio River.