Research review: lurking barnacles

Anyone interested in following the Northeast Regional Invasive Species & Climate Change (RISCC) list-serv which provides ‘… a forum for information exchange surrounding the question “How can we manage for upcoming biological invasions in the light of climate change?”’ can send a message to the list administrator at aeb286@cornell.edu. See below for a sample ~

From: bounce-122443775-78964163@list.cornell.edu [mailto:bounce-122443775-78964163@list.cornell.edu] On Behalf Of Bethany Bradley
Sent: Thursday, April 05, 2018 11:12 AM
To: ne_riscc-l@list.cornell.edu
Subject: Research review: lurking barnacles

This week's paper is original research (not a review or meta-analysis) that fits within a theme of 'sleeper species'.  These are non-natives that are naturalized, but are currently prevented from becoming invasive by unsuitable climate.  With climate change, there is concern that some 'sleeper species' could become invasive.  You'll see a few more papers on this topic in coming weeks.  Click the citation for a link to the paper.

Witte, S., Buschbaum, C., van Beusekom, J. E., & Reise, K. (2010). Does climatic warming explain why an introduced barnacle finally takes over after a lag of more than 50 years?. Biological Invasions, 12(10), 3579-3589.

Summary

Under changing climate conditions, introduced species that were once innocuous may reach invasive status if these conditions become more favorable. Here, the authors investigate an invasive barnacle (Austrominius modestus) that was first recorded off the coast of southern Britain in 1955, suffered a large decline after a particularly cold winter in 1995/1996, and has come to dominate in abundance over native species by 2007. After surveys of the two native barnacles and the invasive barnacle, the authors suggest that no other environmental variables (e.g. changes in salinity, food resources, space limitation, competition), besides temperature were likely to cause the changes in population structure. One reason the authors believe temperature is so important here is because the invasive species comes from warmer climates and is limited by cold winters, while one of the native species has a more northern/ boreal range. The authors conclude that biomass of the new ecosystem, now dominated by an invasive, may be more robust to other impacts of climate change. However this comes at the cost of losing local diversity.

Take Home

• "Sleeper species" like the barnacle described here are naturalized species that are prevented from becoming invasive by intolerance to current climate.  
• Sleeper species are distinct from species experiencing a lag time:

“The awakening of ecological sleepers after decades due to global warming is in contrast with the common pattern of introduced aliens which after a short initial phase enter a boom and bust development, followed by a long adjustment phase with more moderate densities (Reise et al. 2006).”

• Cold limited naturalized species may be able to take advantage of more mild winters and become invasive. 
• Sources of introduction for aquatic introductions typically tend to be from warmer climates (e.g. warm water ports, aquaculture facilities) making these naturalized species potentially problematic.

Management

• Pay attention to naturalized species that originate in a warmer climate, particularly those that are cold limited.
• Focus on pathways that introduce invaders from warmer to cooler climates (e.g. invasives from ballast water typically come from warm water ports)

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Bethany A Bradley
Associate Professor
Department of Environmental Conservation
318 Holdsworth Hall
University of Massachusetts
Amherst, MA 01003

http://people.umass.edu/bethanyb/