Globalization, biological invasions, and ecosystem changes in North America’s Great Lakes

INTRODUCTION Globalization, in the context of biological invasions, is the increased movement of species around the world. In this chapter, non-indigenous species (NIS) are defined as taxa moved from one geographic location of the world to another from which they were historically absent. The largest geographic barriers to species dispersal, the world’s oceans, have been circumvented by the development of a global economy. Increased demand for and transport of goods has resulted in the transfer - both intentional and unintentional - of NIS on unprecedented scales. For example, colonization rates of European crustaceans in North America are estimated to be 50 000 times background levels associated with natural dispersal (Hebert and Cristescu 2002). A number of dispersal vectors are responsible for transport of aquatic NIS, though transoceanic shipping has played a particularly important role as the global economy has expanded. Establishment of NIS represents one of the most significant threats to the world’s indigenous biota (Mooney and Drake 1989; Mack et al. 2000), in addition to adverse ecological and economic effects that they impart on lakes throughout the world (e.g., Hall and Mills 2000). For example, establishment of Nile perch (Lates niloticus) in Lake Victoria and peacock bass (Cichla ocellaris) in Gatun Lake resulted in extirpation or decline of native fish species (Zaret and Paine 1973; Ogutu-Ohwaya 1990; Witte et al. 1992). © Cambridge University Press 2007

Bridging troubled waters: Biological invasions, transoceanic shipping, and the Laurentian Great Lakes

Release of contaminated ballast water by transoceanic ships has been implicated in more than 70% of faunal nonindigenous species (NIS) introductions to the Great Lakes since the opening of the St. Lawrence Seaway in 1959. Contrary to expectation, the apparent invasion rate increased after the initiation of voluntary guidelines in 1989 and mandatory regulations in 1993 for open-ocean ballast water exchange by ships declaring ballast on board (BOB). However, more than 90% of vessels that entered during the 1990s declared no ballast on board (NOBOB) and were not required to exchange ballast, although their tanks contained residual sediments and water that would be discharged in the Great Lakes. Lake Superior receives a disproportionate number of discharges by both BOB and NOBOB ships, yet it has sustained surprisingly few initial invasions. Conversely, the waters connecting Lakes Huron and Erie are an invasion hotspot despite receiving disproportionately few ballast discharges. Other vectors, including canals and accidental release, have contributed NIS to the Great Lakes and may increase in relative importance in the future. Based on our knowledge of NIS previously established in the basin, we have developed a vector assignment protocol to systematically ascertain vectors by which invaders enter the Great Lakes

Lake Ontario zooplankton in 2003 and 2008: Community changes and vertical redistribution

<div><p>Lake-wide zooplankton surveys are critical for documenting and understanding food web responses to ecosystem change. Surveys in 2003 and 2008 during the binational intensive field year in Lake Ontario found that offshore epilimnetic crustacean zooplankton declined by a factor of 12 (density) and factor of 5 (biomass) in the summer with smaller declines in the fall. These declines coincided with an increase in abundance of <i>Bythotrephes</i> and are likely the result of direct predation by, or behavioral responses to this invasive invertebrate predator. Whole water column zooplankton density also declined from 2003 to 2008 in the summer and fall (factor of 4), but biomass only declined in the fall (factor of 2). The decline in biomass was less than the decline in density because the average size of individual zooplankton increased. This was due to changes in the zooplankton community composition from a cyclopoid/bosminid dominated community in 2003 to a calanoid dominated community in 2008. The increase in calanoid copepods was primarily due to the larger species <i>Limnocalanus macrurus</i> and <i>Leptodiaptomus sicilis</i>. These cold water species were found in and below the thermocline associated with a deep chlorophyll layer. In 2008, most of the zooplankton biomass resided in or below the thermocline during the day. Increased importance of copepods in deeper, colder water may favor Cisco and Rainbow Smelt over Alewife because these species are better adapted to cold temperatures than Alewife.</p></div

BioTIME : a database of biodiversity time series for the Anthropocene [data paper]

Motivation: The BioTIME database contains raw data on species identities and abundances in ecological assemblages through time. These data enable users to calculate temporal trends in biodiversity within and amongst assemblages using a broad range of metrics. BioTIME is being developed as a community-led open-source database of biodiversity time series. Our goal is to accelerate and facilitate quantitative analysis of temporal patterns of biodiversity in the Anthropocene. Main types of variables included: The database contains 8,777,413 species abundance records, from assemblages consistently sampled for a minimum of 2 years, which need not necessarily be consecutive. In addition, the database contains metadata relating to sampling methodology and contextual information about each record. Spatial location and grain: BioTIME is a global database of 547,161 unique sampling locations spanning the marine, freshwater and terrestrial realms. Grain size varies across datasets from 0.0000000158 km(2) (158 cm(2)) to 100 km(2) (1,000,000,000,000 cm(2)). Time period and grainBio: TIME records span from 1874 to 2016. The minimal temporal grain across all datasets in BioTIME is a year. Major taxa and level of measurement: BioTIME includes data from 44,440 species across the plant and animal kingdoms, ranging from plants, plankton and terrestrial invertebrates to small and large vertebrates