Changes in population characteristics and structure of the signal crayfish at the edge of its invasive range in a European river

Abstract

-The ability of rapid range expansion is one of the key determinants of invasive species success. In order to investigate potential drivers behind the rapid spread of invasive species, we explored changes in population characteristics and structure along the invasion pathway of a successful invader in European freshwaters, the signal crayfish (Pacifastacus leniusculus). Diverse population parameters such as relative population abundance, size and sex structure, differences in morphometry and frequency of injuries were compared between signal crayfish population samples at three uniformly distributed segments (approximately 40 km apart) in the lower section of the Mura River, which differed in time since invasion. Examined signal crayfish populations exhibited notable differences, with more recently established populations toward invasion front characterized by lower abundance and male-biased sex ratios, which highlighted males as initial dispersers. We also recorded significant increase in the relative claw size, a competitively advantageous and allometric trait for males, in more recently established populations away from source population. The recorded differences in population structure and male morphometry along the invasion pathway could lead to important clues about dynamics of range expansion and population establishment, highlighting the traits that promote dispersal and better response to local conditions in new habitats. Established differences can also provide insights into the development of targeted management responses aimed at invasive species control.

Phenotypic variability of rusty crayfish (Faxonius rusticus) at the leading edge of its riverine invasion

“…However, a significant increase in relative claw size away from source population was also observed in invasive signal crayfish males of the Mura River, Croatia (Hudina et al, 2012). When these resources are plentiful in pioneer populations, behavioural phenotypes associated with large claws and weight as part of an aggression syndrome (Hudina et al, 2012) could therefore lead to unnecessary energy expenses and reduced foraging, leading to reduced fitness (Sih, Cote, Evans, Fogarty, & Pruitt, 2012). Crayfish with shorter chelae and more fusiform body are better able to withstand high water velocities, as suggested by morphologic differences between crayfish found in high-velocity streams compared to those in low-velocity streams and lakes (Perry et al, 2013).…”

“…ground beetle Merizodus soledadinus, Laparie, Renault, Lebouvier, & Delattre, 2013), fish (e.g. signal crayfish Pacifastacus leniusculus, Hudina, Hock, Žganec, & Lucić, 2012). signal crayfish Pacifastacus leniusculus, Hudina, Hock, Žganec, & Lucić, 2012).…”

“…In invaded ecosystems, native crayfish species can be displaced within a few years, and populations of macrophytes, insects, snails, and fish often decline (Bobeldyk & Lamberti, 2010;McCarthy, Hein, Olden, & Vander Zanden, 2006;Olden, McCarthy, Maxted, Fetzer, & Vander Zanden, 2006;Rosenthal, Stevens, & Lodge, 2006). Changes in population structure, behaviour, morphology, and physiology have already been reported between core and edge populations in several ongoing river invasions by crayfish (Hudina, Zganec, & Hock, 2015;Hudina et al, 2012;Pârvulescu, Pîrvu, Moroşan, & Zaharia, 2015;Rebrina, Skejo, Lucić, & Hudina, 2015). At the biogeographical level, differences in growth, survival, feeding habits, and behaviour are also common among crayfish congeners between their native and non-native range, further demonstrating the potential phenotypic changes wrought by the invasion process (Glon, Reisinger, & Pintor, 2018;Pintor & Sih, 2009;Reisinger, Elgin, Towle, Chan, & Lodge, 2017;Sargent & Lodge, 2014).…”

Distribution and establishment of the alien Australian redclaw crayfish,Cherax quadricarinatus, in South Africa and Swaziland

“…In the Lomati River, crayfish were less abundant (average 0.2 indv trap night −1 ), probably reflecting either a more recent invasion or a less suitable habitat (Hudina et al, 2012). The Lomati River is less regulated than the Komati River, containing fewer gauging weirs and consequently having higher flow velocity (AC Hoffman & AL Nunes, pers.…”

The long-term effects of invasive signal crayfish (Pacifastacus leniusculus) on instream macroinvertebrate communities

“…Hudina et al, 2012;Holdich et al, 2014;Kouba et al, 2014). They are one of the largest freshwater invertebrates, frequently dominating benthic faunal biomass where they occur (Lodge and Hill, 1994;Momot, 1995;Sousa et al, 2013).…”