Historical baselines in marine bioinvasions: Implications for policy and management

Abstract

The human-mediated introduction of marine non-indigenous species is a centuries- if not millennia-old phenomenon, but was only recently acknowledged as a potent driver of change in the sea. We provide a synopsis of key historical milestones for marine bioinvasions, including timelines of (a) discovery and understanding of the invasion process, focusing on transfer mechanisms and outcomes, (b) methodologies used for detection and monitoring, (c) approaches to ecological impacts research, and (d) management and policy responses. Early (until the mid-1900s) marine bioinvasions were given little attention, and in a number of cases actively and routinely facilitated. Beginning in the second half of the 20th century, several conspicuous non-indigenous species outbreaks with strong environmental, economic, and public health impacts raised widespread concerns and initiated shifts in public and scientific perceptions. These high-profile invasions led to policy documents and strategies to reduce the introduction and spread of non-indigenous species, although with significant time lags and limited success and focused on only a subset of transfer mechanisms. Integrated, multi-vector management within an ecosystem-based marine management context is urgently needed to address the complex interactions of natural and human pressures that drive invasions in marine ecosystems.

Identifying potentially invasive non‐native marine and brackish water species for the Arabian Gulf and Sea of Oman

“…Particularly important actions include the identification of potential invasive NNS that could enter a region, early detection of those already there (Chan et al, ; Ojaveer et al, ), and prevention of further introductions. On the contrary, post‐introduction actions such as eradication, control and containment are generally difficult and unlikely to be successful (Williams & Grosholz, ), particularly in the marine environment (Werschkun et al, ).…”

A four‐component classification of uncertainties in biological invasions: implications for management

“…Determining the status of species as alien or native is especially problematic in the marine realm and for microbial and soil organisms, in which cases long‐term historical records are scarce and many species are cryptogenic (Ojaveer et al. ). Furthermore, since humans have relocated species as they have moved and traded around the globe for millennia (Hulme ), different alien species at the same location are likely to have different residence times.…”

“…Sources of error have both human and taxonomic dimensions, and inadequate data resolution or availability are also problematic (i.e., measurement errors and systematic errors; Box 1; see McGeoch et al 2012 for a detailed list of such uncertainties). Determining the status of species as alien or native is especially problematic in the marine realm and for microbial and soil organisms, in which cases long-term historical records are scarce and many species are cryptogenic (Ojaveer et al 2018). Furthermore, since humans have relocated species as they have moved and traded around the globe for millennia (Hulme 2009), different alien species at the same location are likely to have different residence times.…”

“…Smaller-scale resolutions may nonetheless be more efficient as an initial step. The European Union (EU) has developed a substantial body of environmental initiatives turned into laws that ensures coordination between countries at the continental scale (Ojaveer et al 2018). Endorsement of such frameworks by the EU could represent a leading action toward global initiatives at the UN level.…”

Prioritizing marine invasive alien species in the European Union through horizon scanning

“…Several of them can be invasive in their new environment, causing biodiversity loss and alterations to ecosystem structure and functions, and may result in socio‐economic impacts (Katsanevakis et al, ; Molnar, Gamboa, Revenga, & Spalding, ; Ojaveer et al, ; Wallentinus & Nyberg, ). Alien species introductions have increased during recent decades, due to globalization and increases in various activities, such as shipping, fisheries, aquaculture, and aquarium trade (Katsanevakis, Zenetos, Belchior, & Cardoso, ; Ojaveer et al, ). European seas may host the highest number of alien species worldwide, with 1,411 alien, cryptogenic, and questionable taxa reported (Tsiamis, Zenetos, Deriu, Gervasini, & Cardoso, ).…”