| Popis: |
Human-driven habitat loss and fragmentation is one of the largest threats to modern biodiversity. The relationship between species and area is one of the oldest patterns observed in ecology; models based on the species–area relationship (SAR) have been used to estimate both local and global extinction rates. A critical difficulty for modern conservation studies is that they are forced to predict the future; empirical testing of these predictions puts at risk the very species the predictions are designed to protect. To help mitigate this problem, we explore the use of the species–area relationship using the paleontological record, which provides empirical data from both before and after species loss. Using species presence/absence data, and a contiguous minimal area grid system, species–area curves (SACs) were constructed for one biofacies in each phase of a transgressive–regressive package. A regression observed for the Pliocene Etchegoin Formation of the San Joaquin Basin (California) inland sea, and the effect of sea-level fall on the perched molluscan fauna, was used as an analogy for modern habitat loss. Using the equation of the species–area curve of the transgressive interval, we predicted the number of species to go extinct in the subsequent regression. To examine extinction severity, we compared these predictions to the data observed for the regressive curve. The results showed that the regressive curve had fewer species than the prediction based on the transgressive curve, suggesting that species loss was more severe than predicted. The results demonstrate an example of how the species–area relationship can be used in the fossil record, and that the paleontological record could be used to provide relevant information for modern conservation problems. |
