Abstract
The Anthropocene has resulted in a large-scale global development, connectivity, and biological homogenization through human created landscapes. Human development can promote invasibility in species that thrive within urbanized landscapes. Florida is particularly susceptible to non-native species success because of characteristics such as extensive transportation networks and a subtropical climate. In addition, an abundance of natural habitat types and disturbed landscapes offer refugia for introduced species. The Brahminy blindsnake (Indotyphlops braminus), Greenhouse frog (Eleutherodactylus planirostris), New Guinea flatworm (Platydemus manokwari), and Yellow-banded millipede (Anadenobolus monilicornis) are all non-native to Florida and appear to be widespread throughout much of the state. Most sightings of these fossorial species take place in areas with ornamental plants, such as nurseries and gardens, but they are often seen in other areas. While these species appear to have spread widely, it is currently unknown if these animals have naturalized evenly across human and natural landscapes. This study assessed densities and distributions of species across human and natural land-use types in Lee County, FL. Land-use types, including areas of urbanization and agriculturalization, showed variation in landcover and environmental conditions. Exotic species were far more common than native species across all land-use types, however they did not distribute themselves evenly across land-use types. Gardens had almost seven times the number of individual organisms than any other land-use type. Detection and occupancy models showed that all exotic species had high occupancy probabilities but detection varied by species and land-use type. These data support the hypothesis that human environments, particularly garden systems, can be important to the invasion process. These findings also show that exotic animals make species-specific use of different human and natural land-use types in Florida. Additionally, detection was low for all species which likely means we are missing them in many places where they occur. It is important to how where non-natives are found and how abundant they are in order to learn more about impacts they might be having. More research and the use of citizen science databases can help fill in the gaps of knowledge for these cryptic, yet ubiquitous species. Exotic species that are thought to be human associated are invading land-use types that are otherwise relatively unimpacted by humans. It not completely clear what the impact this is having on native species and ecosystems, but it is clear that these exotic fossorial animals are there and in higher numbers than previously thought. Human environments and the variation among land-use types should be examined to understand how introduced species go from exotic to invasive.
