It is commonly assumed that global biodiversity is in decline because of the increasing impact of anthropogenic influences, especially habitat loss. To mitigate habitat loss, many countries with biodiversity hotspots have attempted to preserve these by establishing protected areas where anthropogenic disturbances are minimized. Historical data that could show how well this strategy is working over decades to centuries is often incomplete or variably accessible in different databases. In this study we compiled extensive historic museum records of mammal diversity in Kenya (collections from early 20th century expeditions to Africa) and compared them to modern mammalian species diversity in six sites where historic sampling efforts correspond with modern protected areas. We compared the community structure of historical sites to modern sites in terms of body size distributions, trophic distributions, and beta diversity across sites and across time. We ran separate tests with all species separated by body size and visibility to address the possibility that smaller, less visible species were undersampled in the historic record.
Results/Conclusions
We conclude that mammal diversity in our sampling locations is stable or has increased from the early 20th century, indicating that these preserves and parks are fulfilling the goal of preserving biodiversity. However, this pattern for individual sites has resulted in communities that are more similar now than they were historically, indicating a marked decrease in community uniqueness across sites over time.