Factors inducing overland movement of invasive crayfish (Procambarus clarkii) in a ricefield habitat

Abstract

The red swamp crayfish (Procambarus clarkii) is a widespread invader which can disperse overland. This study was conducted to determine which factors can induce overland dispersal. During 12 months, the numbers of P. clarkii out of water were monitored at an experimental rice research station. Data were obtained on preferential time period for overland dispersal; population structure on land and in water; direction of movement; and the relation between environmental variables and the occurrence of crayfish out of water. A main factor inducing overland dispersal was intentional drainage of the study area associated with rice cultivation. During post-drainage, crayfish dispersal overland was positively correlated with rainfall. Other variables significantly affecting the overland dispersal of crayfish were the relative humidity, air temperature and the period of the day. We found significant differences in the structure of the trappable population in the water and of the individuals out of the water, with a higher proportion of mature individuals dispersing overland. Because overland migrants were dominated by mature individuals, often with eggs or hatchlings attached to the abdomen, these may effectively colonize new areas.

Transmission and terrestrial dispersal of non-native ectosymbionts on invasive crayfish

“…The terrestrial walking speed of signal crayfish is unknown, but adult male red swamp crayfish (Procambarus clarkii Girard, 1852), another invasive North American species, walk on average 58 m h -1 (Ramalho & Anastácio, 2014). At this rate, we estimate X. victoriensis could survive terrestrial migration up to 43.5 m, although this does not take into account variable environmental conditions (Marques et al, 2014;Ramalho & Anastácio, 2014;Yoder et al, 2016).…”

“…It is also possible that branchiobdellidans could tolerate longer periods of desiccation in vivo by retreating into host crevices or gill chambers, but for X. victoriensis this is unlikely given that this species is a chelae specialist (Gelder & Hall, 1990;James et al, 2015b). Regardless, it is likely that even based on our conservative estimates, branchiobdellidans would be able to survive natural crayfish overland dispersal, which can exceed 20 m (Puky, 2014;Ramalho & Anastácio, 2014). Cocoons present another opportunity for dispersal: oligochaete cocoons, for example, can have a higher desiccation tolerance than juvenile and adult worms (Holmstrup, 2001;Govedich et al, 2009).…”

“…The terrestrial walking speed of signal crayfish is unknown, but adult male red swamp crayfish (Procambarus clarkii Girard, 1852), another invasive North American species, walk on average 58 m h -1 (Ramalho & Anastácio, 2014). At this rate, we estimate X. victoriensis could survive terrestrial migration up to 43.5 m, although this does not take into account variable environmental conditions (Marques et al, 2014;Ramalho & Anastácio, 2014;Yoder et al, 2016). It is also possible that branchiobdellidans could tolerate longer periods of desiccation in vivo by retreating into host crevices or gill chambers, but for X. victoriensis this is unlikely given that this species is a chelae specialist (Gelder & Hall, 1990;James et al, 2015b).…”

“…Amphibious behaviour, however, offers not only opportunities for foraging, reproduction and escape from unfavourable conditions, but terrestrial emigration to nearby water bodies (Sayer & Davenport, 1991). This has played an important role in the spread of invasive non-native species (Peterson et al, 2013;Marques et al, 2014;Ramalho & Anastácio, 2014;Fialho et al, 2016). Invasive species can detrimentally affect biodiversity, human health and industry in their introduced range (Mack et al, 2000), and determining their dispersal capacity is paramount for non-native species risk assessments (Johnson & Padilla, 1996).…”

“…Certain species have the capacity to disperse up to 1 km overland and move between isolated water bodies (Lutz & Wolters, 1999;Ramalho & Anastácio, 2014;Fialho et al, 2016), where they act as ecosystem engineers and interact with organisms on multiple trophic levels (Gherardi, 2007;Strayer, 2010;James et al, 2015a). Because of their success and impact, invasive crayfish are considered a major cause of biodiversity loss (Lodge et al, 2000;Manchester & Bullock, 2000).…”