Non-native plants negatively impact ecosystems via a variety of mechanisms, including in forested riparian areas. Japanese knotweed [Polygonum cuspidatum Siebold & Zucc.] and its hybrids (referred to as Polygonum spp. hereafter) are widely spread throughout North America and can impact flora and fauna of riparian habitats. Thus, information improving our ability to understand and predict the potential spread and colonization of Polygonum spp. is valuable. One dispersal mechanism is hydrochory (i.e., dispersal by water), including the downstream dispersal of viable stems that can facilitate rapid invasion within a watershed. We used passive integrated transponder (PIT) telemetry in experimental releases of Polygonum spp. stems to track the downstream transport of Polygonum spp. in a small (second-order) stream in northern New Hampshire, USA, in the summers of 2021 and 2022. A total of 180 (90 each year) Polygonum spp. stems were released at three sites within the stream reach, with 185 (∼98%) being recaptured at least once, with a total of 686 recaptures. Individual relocated stems moved a maximum distance of 30 to 875 m downstream in 2021 and 13 to 1,233 m in 2022 during regular flows; however, a high-streamflow event in July 2021 flushed out all remaining stems downstream of the study area. Generalized additive mixed models (GAMMs) identified site-specific differences in stem movement rates and a general reduction in movement rates with increased duration of time elapsed since post-release. In general, Polygonum spp. stems moved farther downstream in sites with lower channel sinuosity, although other fine-scale habitat factors (e.g., water depth, habitat type, and presence of wood and debris jams) likely contribute to the ability for Polygonum spp. to further disperse or otherwise be retained within the channel. Thus, stream morphology and stream flow are likely to affect where Polygonum spp. stems will be retained and potentially reestablish. Predictive tools identifying areas of higher probability of hydrochory-based dispersal could help to focus removal efforts when employed or to identify riparian habitats at highest risk for spread.

An account of code-switching should be a direct consequence of an understanding of representation and processing in the individual mind, rather than a separate domain of its own. In the absence of such an account, most studies have developed hypotheses strictly within a specific research domain. This paper seeks to apply to code-switching a reasonably well-developed account of the multilingual mind, the MOGUL framework, within which more specific accounts can be developed. After briefly summarizing the framework, we describe representation and processing as realized in MOGUL, focusing on aspects having particular relevance to code-switching, including social factors involved in switching but as seen in terms of their place in a cognitive system. We then show how a promising approach to code-switching can be derived from this general framework. Some specific examples of code-switching are analyzed, though the primary goal is to show the merits of a broader perspective.