Fitness-related traits are maximized in recently introduced, slow-growing populations of a global invasive clam

Abstract

Fitness-related traits are maximized in recently introduced, slow-1 growing populations of an invasive clam: is this a response to strong r-2 selection? 3 4 ABSTRACT 27Many species are shifting their ranges being forced to rapidly respond to novel stressful 28 environmental conditions. Colonizing individuals experience a complex mixture of 29 selective forces that favor rapid evolution of life history traits notably affecting dispersal 30 and reproductive rates in newly invaded habitats. Limited information is currently 31 available on trait variation within the invasive range despite being critical for 32 understanding ecological and evolutionary factors that drive the process of range 33 expansion of invasive species. Here we evaluated life history shifts of the widely 34 introduced Asian clam Corbicula within its invaded range. Through an exhaustive 35 literature search, we obtained data for 17 invasive Corbicula populations from different 36 ecosystems worldwide to test the relationship between population and individual 37 parameters relevant to the process of range expansion. Our main results show that (i) 38 recently introduced Corbicula populations are characterized by low conspecific density 39 and low population growth rate, (ii) clams reproduce earlier in slow-growing 40populations, and (iii) density had no effect on population increase. Our findings support 41 the standpoint that individuals from recently established populations of Corbicula face 42 strong r-selective forces that favor traits associated with high reproductive rates, which 43 could be interpreted as an effective mechanism to overcome difficulties associated with 44 low densities and low population growth in newly colonized areas. 45 46 47 The ongoing increase in frequency of extreme climatic events, caused by anthropogenic 48 climate change, and global transport of people and goods is altering ecosystems by 49 triggering a wide array of irreversible consequences (Walther et al. 2002; Bossdorf et al. 50 2005; Hoegh-Guldberg and Bruno 2010; IPCC 2014). Changes in local conditions, in 51 particular those driven by human-induced climate change, are predicted to affect 52 ecological processes across several levels of organization, likely over the coming 53 decades. Such changes are altering the performance of individual organisms, the 54 dynamics of populations and the distribution of species, ultimately modifying 55 ecosystem properties and function (Hoffmann and Sgró 2011; Lonhart et al. 2019). 56 Hence, many species are forced to rapidly respond to novel stressful environmental 57 conditions when shifting their distribution and colonizing new areas. 58 59 If non-native species have difficulties in adapting to such conditions and fail to track 60 projected environmental changes, populations become vulnerable to decline and 61 extinction (Hill et al. 2011; Hoffmann and Sgró 2011; Strayer et al. 2017). These 62 stressful conditions can have a strong effect on species life histories through the 63 selection of traits that optimize populati...

Understanding the complex dynamics of zebra mussel invasions over several decades in European rivers: drivers, impacts and predictions

“…1), thereby increasing the propagule pressure and thus, the likely invasion success of D. polymorpha in recent years (Lockwood et al 2009, Lorencová et al 2015, Soto et al 2023a). Nevertheless, it is possible that other variables (Hünicken et al 2022) were also important but unavailable to us. Propagule pressure, in particular from highly infested lakes connected to running water, is considered highly relevant in the case of intentionally introduced species, but arguably more difficult to evaluate in the case of accidental introductions (Blackburn et al 2013).…”