Browsing by Author "Dick, J. T. A."

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    Four priority areas to advance invasion science in the face of rapid environmental change
    (Canadian Science Publishing, 2021) Ricciardi, A.; Iacarella, J. C.; Aldridge, D. C.; Blackburn, T. M.; Carlton, J. T.; Catford, J. A.; Dick, J. T. A.; Hulme, P. E.; Jeschke, J. M.; Liebhold, A. M.; Lockwood, J. L.; MacIsaac, H. J.; Meyerson, L. A.; Pysek, P.; Richardson, D. M.; Ruiz, G. M.; Simberloff, D.; Vila, M.; Wardle, D. A.
    Unprecedented rates of introduction and spread of non-native species pose burgeoning challenges to biodiversity, natural resource management, regional economies, and human health. Current biosecurity efforts are failing to keep pace with globalization, revealing critical gaps in our understanding and response to invasions. Here, we identify four priority areas to advance invasion science in the face of rapid global environmental change. First, invasion science should strive to develop a more comprehensive framework for predicting how the behavior, abundance, and interspecific interactions of non-native species vary in relation to conditions in receiving environments and how these factors govern the ecological impacts of invasion. A second priority is to understand the potential synergistic effects of multiple co-occurring stressors— particularly involving climate change—on the establishment and impact of non-native species. Climate adaptation and mitigation strategies will need to consider the possible consequences of promoting non-native species, and appropriate management responses to non-native species will need to be developed. The third priority is to address the taxonomic impediment. The ability to detect and evaluate invasion risks is compromised by a growing deficit in taxonomic expertise, which cannot be adequately compensated by new molecular technologies alone. Management of biosecurity risks will become increasingly challenging unless academia, industry, and governments train and employ new personnel in taxonomy and systematics. Fourth, we recommend that internationally cooperative biosecurity strategies consider the bridgehead effects of global dispersal networks, in which organisms tend to invade new regions from locations where they have already established. Cooperation among countries to eradicate or control species established in bridgehead regions should yield greater benefit than independent attempts by individual countries to exclude these species from arriving and establishing.
  • Thumbnail Image
    Item
    Functional responses can unify invasion ecology
    (Springer, 2017-01-18) Dick, J. T. A.; Alexander, M. E.; Ricciardi, A.; Laverty, C.; Downey, P. O.; Xu, M.; Jeschke, J. M.; Saul, W. C.; Hill, M. P.; Wasserman, R.; Barrios-O'Neill, D.; Weyl, O. L. F.; Shaw, R. H.
    We contend that invasion ecology requires a universal, measurable trait of species and their interactions with resources that predicts key elements of invasibility and ecological impact; here, we advocate that functional responses can help achieve this across taxonomic and trophic groups, among habitats and contexts, and can hence help unify disparate research interests in invasion ecology.
  • Thumbnail Image
    Item
    Influence of intra- and interspecific variation in predator-prey body size ratios on trophic interaction strengths
    (Wiley Online, 2020) Cuthbert, R. N.; Wasserman, R. J.; Dalu, T.; Kaiser, H.; Weyl, O. L. F.; Dick, J. T. A.; Sentis, A.; McCoy, M. W.; Alexander, M. E.
    Predation is a pervasive force that structures food webs and directly influences ecosystem functioning. The relative body sizes of predators and prey may be an important determinant of interaction strengths. However, studies quantifying the combined influence of intra- and interspecific variation in predator-prey body size ratios are lacking. We use a comparative functional response approach to examine interaction strengths between three size classes of invasive bluegill and largemouth bass toward three scaled size classes of their tilapia prey. We then quantify the influence of intra- and interspecific predator-prey body mass ratios on the scaling of attack rates and handling times. Type II functional responses were displayed by both predators across all predator and prey size classes. Largemouth bass consumed more than bluegill at small and intermediate predator size classes, while large predators of both species were more similar. Small prey were most vulnerable overall; however, differential attack rates among prey were emergent across predator sizes. For both bluegill and largemouth bass, small predators exhibited higher attack rates toward small and intermediate prey sizes, while larger predators exhibited greater attack rates toward large prey. Conversely, handling times increased with prey size, with small bluegill exhibiting particularly low feeding rates toward medium-large prey types. Attack rates for both predators peaked unimodally at intermediate predator-prey body mass ratios, while handling times generally shortened across increasing body mass ratios. We thus demonstrate effects of body size ratios on predator-prey interaction strengths between key fish species, with attack rates and handling times dependent on the relative sizes of predator-prey participants. Considerations for intra- and interspecific body size ratio effects are critical for predicting the strengths of interactions within ecosystems and may drive differential ecological impacts among invasive species as size ratios shift.