Patterns and traits associated with invasions by predatory marine crabs

Abstract

Predatory crabs are considered amongst the most successful marine invasive groups. Nonetheless, most studies of these taxa have been descriptive in nature, biased towards specific species or regions and have seldom considered traits associated with invasiveness. To address this gap in knowledge, this study presents a global review of invasions by this group and applies biological trait analysis to investigate traits associated with invasion success. A total of 56 species belonging to 15 families were identified as having spread outside their native ranges. The family Portunidae supported the highest number of alien species (22). Most crabs had their origin in the North West Pacific IUCN bioregion while the Mediterranean Sea received the most species. No traits associated with successful establishment were identified, but this finding may reflect the paucity of basic biological knowledge held for many species. This lack of foundational knowledge was unexpected as crabs are large and conspicuous and likely to be well studied when compared to many other groups. Addressing this knowledge gap will be the first step towards enabling approaches like biological trait analysis that offer a means to investigate generalities in invasions.

Invasion syndromes: a systematic approach for predicting biological invasions and facilitating effective management

“…if invasions are simply not possible due to incompatible environmental conditions, or if an invasion is likely to result from the introduction of a single propagule; Bacon et al 2014;Duncan et al 2014). Similarly, while the positive relationship between native range size and the likelihood of an alien species becoming established and/or causing an undesirable impact has been demonstrated for some aquatic (Bates et al 2013), bird (Duncan et al 2001), mammal (Forsyth et al 2004) and plant (Pyšek et al 2009;Hui et al 2011;Moodley et al 2013;Potgieter et al 2014;Moodley et al 2016;Novoa et al 2016b) species, such correlations are not always clear-cut (Jeschke and Strayer 2006;Swart et al 2018). New formulations and fine-tuning of generalizations are thus needed (Jeschke et al 2012;Kueffer et al 2013).…”

Prey size selection in invasive (Hemigrapsus sanguineus and H. takanoi) compared with native (Carcinus maenas) marine crabs

“…In marine ecosystems, decapod crabs are among the most prominent invasive predators, often causing strong effects on recipient communities (Brockerhoff & McLay, 2011; Kotta et al ., 2018; Swart et al ., 2018). Arguably best studied in this respect is the invasion of European shore crabs ( Carcinus maenas ) along North American shores, where experimental work over the last decades has identified an overlap of the prey species spectrum and prey size preferences with native and other invasive crabs, with subsequent diverse effects on the invaded marine communities (see review by Klassen & Locke, 2007).…”

Double trouble: the implications of climate change for biological invasions

“…cryptic invasions often go unrecognised (Morais and Reichard 2018)), natural history (e.g. life-history traits are seldom quantified, even for taxa considered to be well studied (Swart et al 2018)), ecology (e.g. species ranges are often not georeferenced or routinely monitored (Pereira and Cooper 2006)), and even invasion biology (e.g.…”