Network analysis of ballast-mediated species transfer reveals important introduction and dispersal patterns in the Arctic

Abstract

Rapid climate change has wide-ranging implications for the Arctic region, including sea ice loss, increased geopolitical attention, and expanding economic activity resulting in a dramatic increase in shipping activity. As a result, the risk of harmful non-native marine species being introduced into this critical region will increase unless policy and management steps are implemented in response. Using data about shipping, ecoregions, and environmental conditions, we leverage network analysis and data mining techniques to assess, visualize, and project ballast water-mediated species introductions into the Arctic and dispersal of non-native species within the Arctic. We first identify high-risk connections between the Arctic and non-Arctic ports that could be sources of non-native species over 15 years (1997–2012) and observe the emergence of shipping hubs in the Arctic where the cumulative risk of non-native species introduction is increasing. We then consider how environmental conditions can constrain this Arctic introduction network for species with different physiological limits, thus providing a tool that will allow decision-makers to evaluate the relative risk of different shipping routes. Next, we focus on within-Arctic ballast-mediated species dispersal where we use higher-order network analysis to identify critical shipping routes that may facilitate species dispersal within the Arctic. The risk assessment and projection framework we propose could inform risk-based assessment and management of ship-borne invasive species in the Arctic.

Integrated Biological Risk and Cost Model Analysis Supports a Geopolitical Shift in Ballast Water Management

“…The standards are different for two categories of “viable organisms” and three categories of “indicator microbes”. These regulations are uniform across ports, but HAOP spread risks vary at different locations. − Stricter regional regulatory standards may be needed to achieve better protection for certain ports, particularly those with high HAOP spread risk or those that serve as key hubs in the global shipping network.…”

Sifting environmental DNA metabarcoding data sets for rapid reconstruction of marine food webs

“…The use of opportunistic network analyses built on eDNA metabarcoding studies could represent a valuable asset to generate an extensive baseline of simplified food web reconstructions, which could help environmental scientists and practitioners monitor a larger portion of our seas and flag possible ongoing anthropogenic disturbance (DiBattista et al., 2020; Gilarranz et al., 2016). These rapidly generated networks have the potential to unveil processes such as the loss of keystone species (Wu et al., 2020), the impact of expanding/invasive species (Saebi et al., 2020), the detrimental impacts of environmental changes on top predators (Sagarese et al., 2017), the depletion of forage taxa that sustain commercially important resources (Lassalle et al., 2011), the ecosystem‐level effect of marine protection (Casselberry et al., 2020), and a variety of other ecological processes that are often latent and difficult to unpick over timescales that are relevant to management.…”

A Path-based Approach to Analyzing the Global Liner Shipping Network

“…The study found that the global shipping network exhibits the small-world property and that there were substantial differences between how ships carrying different cargo navigated the network, suggesting implications for the spread of invasive species through ship ballasts. This latter result was built upon in [7,17] (among others), where a network approach was again applied to AIS data to study the transfer of invasive species in ballasts of ships. The second study used techniques from higher-order network analysis, specifically the variable-order network model developed in [18], to show that incorporating sequential information improves prediction of invasive species movements.…”