The Galapagos Islands are famed for their beauty and ecological diversity. They are also known for playing an integral part in the formation of Charles Darwin’s theories of evolution and natural selection. The Galapagos Islands even have their own group of finches known as Darwin’s Finches. These finches were foundational to Darwin’s theory of evolution, recorded in The Origin of Species. Darwin created his theory of evolution by analyzing the finch’s beak sizes. The Galapagos Islands have a tropical climate, and frequently experience El Niño and La Niña oscillations. This tropical climate comes with high variability in temperature and precipitation, which can affect the reproductivity of the Darwinian Finches under climate change. The main objective of this study is to investigate the relationship between the reproductivity of two species of finches, Geospiza fortis and Geospiza scandens, and environmental factors and utilize that relationship to predict the reproductivity of the Darwin Finches in the short and long term under scenarios of climate change. Studies have shown that increased rainfall during El Niño results in hatching success up to some extent, but beyond a threshold rainfall, it starts decreasing.
Results/Conclusions
Our hypothesis is that climate projections, precipitation and El Niño and La Niña cycles, could be utilized to evaluate the impacts of Finches’ reproductive rates. To evaluate this, we acquired precipitation and finch reproductivity data from the book 40 Years of Evolution: Darwin's Finches on Daphne Major Island by Drs. Peter and Rosemary Grant developed a quadratic regression model that relates observed rainfall to the observed hatchling rates for the Geospiza fortis species (R2 = 0.6 and p-value is 0.006). For the Geospiza scandens species, we only obtained an R2 of 0.08 and a p-value of 0.64. Using future climate projections (rainfall), from Climate Model Intercomparison Project-6 (CMIP6), we applied the quadratic model to predict finch reproductive rates in 2050 and 2100. Our analysis from CMIP6 climate projections showt similar reproductivity patterns are expected under climate change, but the Finches reproductivity could be substantially increased with increased frequency of extreme rainfall. We will also present why the trends are so strong for the Geospiza fortis species and weak for the Geospiza scandens species. This implies that impacts of climate change could potentially have different responses at species level, hence we suggest species-level impact analysis with macro-level impacts.
