Refine
Year of publication
- 2013 (1)
Document Type
- Article (2)
Language
- English (2) (remove)
Has Fulltext
- yes (2)
Is part of the Bibliography
- no (2)
Keywords
- forest ecosystems (2) (remove)
Over the last few decades, considerable attention has focused on small-scale studies of invasive plants and invaded systems. Unfortunately, small scale studies rarely provide comprehensive insight into the complexities of biological invasions at macroscales. Systematic and repeated monitoring of biological invasions at broad scales are rare. In this report, we highlight a unique invasive plant database from the national Forest Inventory and Analysis (FIA) program of the United States Forest Service. We demonstrate the importance and capability of this subcontinental-wide database by showcasing several critical macroscale invasion patterns that have emerged from its initial analysis: (1) large portion of the forests systems (39%) in the United States are impacted by invasive plants, (2) forests in the eastern United States harbor more invasive species than the western regions, (3) human land-use legacies at regional to national scalesb may drive large-scale invasion patterns. This accumulated dataset, which continues to grow in temporal richness with repeated measurements, will allow the understanding of invasion patterns and processes at multi-spatial and temporal scales. Such insights are not possible from smaller-scale studies, illustrating the benefit that can be gained by investing in the development of regional to continental-wide invasion monitoring programs elsewhere.
Increasing trends in global trade make it extremely difficult to prevent the entry of all potential invasive species (IS). Establishing early detection strategies thus becomes an important part of the continuum used to reduce the introduction of invasive species. One part necessary to ensure the success of these strategies is the determination of priority survey areas based on invasion pressure. We used a pathway-centred conceptual model of pest invasion to address these questions: what role does global trade play in invasion pressure of plant ecosystems and how could an understanding of this role be used to enhance early detection strategies? We concluded that the relative level of invasion pressure for destination ecosystems can be influenced by the intensity of pathway usage (import volume and frequency), the number and type of pathways with a similar destination, and the number of different ecological regions that serve as the source for imports to the same destination. As these factors increase, pressure typically intensifies because of increasing a) propagule pressure, b) likelihood of transporting pests with higher intrinsic invasion potential, and c) likelihood of transporting pests into ecosystems with higher invasibility. We used maritime containerized imports of live plants into the contiguous U.S. as a case study to illustrate the practical implications of the model to determine hotspot areas of relative invasion pressure for agricultural and forest ecosystems (two ecosystems with high potential invasibility). Our results illustrated the importance of how a pathway-centred model could be used to highlight potential target areas for early detection strategies for IS. Many of the hotspots in agricultural and forest ecosystems were within major U.S. metropolitan areas. Invasion ecologists can utilize pathway-centred conceptual models to a) better understand the role of human-mediated pathways in pest establishment, b) enhance current methodologies for IS risk analysis, and c) develop strategies for IS early detection-rapid response programs.