Bioinvasions are a growing threat to biodiversity, but our ability to predict and control bioinvaders is hampered by a lack of timely and accessible information. While ecological monitoring is the primary way in which bioinvasions are detected and tracked, there are other reliable sources of information, such as online reporting databases, citizen scientists, and social surveys of resource users. The problem is that actors within the various domains are guided by different objectives and investigative approaches, creating barriers to information sharing and effective application. We aimed to develop a method to integrate disparate datasets into a model describing abundance and spatial extent of an invasive species and to determine what each information source contributes to our understanding of population dynamics. Using a case study approach, we collected and integrated monitoring, online, and crabber survey data on two recently introduced species, the Asian shore crab (Hemigrapsus sanguineus) and Chinese mitten crab (Eriocheir sinensis) in the Hudson-Raritan watershed. We used Poisson regression and range size analyses to explore the relative contribution of each information source by comparing whether the parameter estimation for models excluding one source of data differed significantly from the model for the full dataset.
Results/Conclusions
All three information sources contributed something unique to our understanding of the abundance and distribution of two introduced crabs in the Hudson-Raritan. For the Asian shore crab, online and survey data significantly impacted predictions for abundance whereas monitoring data did not. When survey data were omitted, the trend for abundance stayed flat over time, but when they were included, the model predicts increased abundance in 2012. All three datasets for the Asian shore crab significantly impacted estimates of spread extent with surveys having the biggest impact, increasing range size by 4097.25 km2. For the catadromous Chinese mitten crab, ecological monitoring data were more important for shaping model estimates for abundance. Monitoring data collected in freshwater habitats shortly after the original sighting significantly shaped abundance model estimates and documented the establishment phase of the mitten crab in an area outside the range frequented by crabbers. However, crabber survey data significantly enlarged mitten crab range size estimates by 6498.01 km2. By demonstrating that data integration produced an image of the invasion process that would not have emerged had we used any one method individually, our results provide evidence for the advantages of an interdisciplinary approach.