Biodiversity

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Visualization of bird diversity. From biodiversitymapping.org

In its simplest term, biodiversity refers to the variety of living things in an area. Biodiversity loss is of concern to conservationists, farmers, and natural resource managers. Ecosystems are complex systems, making assessments of the impact of climate change on biodiversity complicated. The same change in a climate variable in one area may yield different results in another. Adaptation practitioners interested in biodiversity require knowledge of the local ecosystem sensitivities to different climate variables.

Primary productivity refers to the amount of photosynthetically driven biological activity in an area. It may be generated by land or aquatic plants (i.e., algae), and ultimately forms the foundation of all ecosystem activity. Changes in incoming solar radiation (e.g., from changes in cloud cover) can impact the amount of primary productivity. Where temperatures are moderate, increases in temperature can increase plant productivity. Where temperatures are already high, further increases may have deleterious effects on productivity. Similarly, increases in rainfall may in many cases lead to an increase in primary productivity, yet flooding or intense rainfall can damage plants and reduce productivity. 

Many species prefer specific climates, and alterations in temperature and precipitation in a region can affect species abundance and distribution. This is especially true for land species. Higher temperatures may cause temperature-sensitive organisms to migrate to cooler locations, such as higher elevations. Changes in precipitation may affect some species more than others; physiological adaptations allow some plants to use water more efficiently, making these species more resistant to decreased precipitation. Changes in the variability of temperature or precipitation can also affect biodiversity, even when the mean for each variable remains steady. Many organisms have temperature or precipitation thresholds that they cannot exceed, and when these thresholds are exceeded species may migrate to more suitable climate zones (if they are able) or risk local extinction.

Finally, the departure of one species can effect the prevalence of others. Organisms that depend on the others (i.e. predators on prey) will likely respond similarly to the same climate variables. In contrast, organisms that compete with one another (i.e., plant species that compete for space) may increase if their competitors prove more sensitive to climate change. Understanding ecosystem responses to climate change requires knowledge of climate sensitivities and local ecosystem dynamics in addition to predictions regarding climate variables. 

Coral reefs exist along the coasts of Ghana, Côte d’Ivoire, and Guinea. They serve as tourist attractions and essential habitats for many economically important marine species. Reef-building coral species enjoy symbiotic relationships with single-cell plankton species called zooxanthellae that are sensitive to temperature changes. The presence of zooxanthellae is what gives coral its vibrant color. Increases in Sea Surface Temperatures (SSTs) can lead to the departure of these zooxanthellae, referred to as “coral bleaching.” Without this relationship most hard coral species struggle to survive. Absent reef-building hard coral, reef structures become degraded and other marine organisms may lose an important habitat.

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