Data from: Urbanized landscapes favored by fig-eating birds increase invasive but not native juvenile strangler fig abundance
Caughlin, Trevor, University of Florida
Wheeler, Jessica H., New College of Florida
Jankowski, Jill, University of Florida
Lichstein, Jeremy W., University of Florida
Published Aug 26, 2014 on Dryad.
Cite this dataset
Caughlin, Trevor; Wheeler, Jessica H.; Jankowski, Jill; Lichstein, Jeremy W. (2014). Data from: Urbanized landscapes favored by fig-eating birds increase invasive but not native juvenile strangler fig abundance [Dataset]. Dryad. https://doi.org/10.5061/dryad.b1q50
Propagule pressure can determine the success or failure of invasive plant range expansion. Range expansion takes place at large spatial scales, often encompassing many types of land cover, yet the effect of landscape context on propagule pressure remains largely unknown. Many studies have reported a positive correlation between invasive plant abundance and human land use; increased propagule pressure in these landscapes may be responsible for this correlation. We tested the hypothesis that increased rates of seed dispersal by fig-eating birds, which are more common in urban habitats, result in an increase in invasive strangler fig abundance in landscapes dominated by human land use. We quantified abundance of an invasive species (Ficus microcarpa) and a native species (F. aurea) of strangler fig in plots spanning the entire range of human land use in South Florida, USA, from urban parking lots to native forest. We then compared models that predicted juvenile fig abundance based on distance to adult fig seed sources and fig-eating bird habitat quality with models that lacked one or both of these terms. The best model for juvenile invasive fig abundance included both distance to adult and fig-eating bird habitat terms, suggesting that landscape effects on invasive fig abundance are mediated by seed-dispersing birds. In contrast, the best model for juvenile native fig abundance included only presence/absence of adults, suggesting that distance from individual adult trees may have less effect on seed limitation for a native species compared to an invasive species undergoing range expansion. However, models for both species included significant effects of adult seed sources, implying that juvenile abundance is limited by seed arrival. This result was corroborated by a seed addition experiment that indicated that both native and invasive strangler figs were strongly seed limited. Understanding how landscape context affects the mechanisms of plant invasion may lead to better management techniques. Our results suggest that prioritizing removal of adult trees in sites with high fig-eating bird habitat may be the most effective method to control F. microcarpa abundance.
Counts of seedling figs and predictor variables in center plots
This data was collected in the field in fifty-two 30 m x 30 m plots in southwest Florida. SITECODE and IDENT columns are unique names for each plot, Y_PROJ and X_PROJ are the UTM coordinates (NAD83/ zone 17N) of the center of each plot, cabbage palms is the number of cabbage palms in each plot, aurea seedlings and microcarpa seedlings are counts of fig seedlings of Ficus aurea and Ficus microcarpa in each plot, canopy cover is estimated canopy cover over each plot (on a scale of 1-5), understory height represents the mean height of understory vegetation (in meters) in each plot and microcarpa and aurea DBH represent the summed DBH (in cm) of all reproductive adult figs in a 300 m radius around each plot.
Location and size of adult Ficus aurea trees
This file contains the size and location of all reproductive adult Ficus aurea trees within 300 m of center plots. The column Sitecode matches the column of the same name in the "Center plots.csv" file. The DBH column is the diameter at breast height in cm of adult trees, Distance is distance from the trunk of the tree to the center of the center plot in m, and y and x are the coordinates in UTM (NAD83/ zone 17N) of each tree.
Location and size of adult Ficus microcarpa trees
This file contains the size and location of all reproductive adult Ficus microcarpa trees within 300 m of center plots. The column Sitecode matches the column of the same name in the "Center plots.csv" file. The DBH column is the diameter at breast height in cm of adult trees, Distance is distance from the trunk of the tree to the center of the center plot in m, and y and x are the coordinates in UTM (NAD83/ zone 17N) of each tree.