Little association of biological trait values with environmental variables in invasive alien round goby (Neogobius melanostomus)

Abstract

The relative importance of species-specific biological trait characteristics and environmental factors in invasions of nonindigenous species remains controversial because both have mostly been studied independently. Thus, the main objective of this study was to examine the correlation of biological traits with environmental variation in the globally invasive round goby Neogobius melanostomus from the upper Danube River.Based on a sample of 653 specimens along a continuous 200 km river pathway, links between nine environmental factors (substrate-type, six water measurements, and the communities of fishes and macroinvertebrates) and seven biological traits (nutritional and energetic status, trade-offs of parasite resistance and resource allocation, and three growth proxies) were analyzed. Biological trait values of N. melanostomus hardly correlated with the environment, could not explain invasion progress and imply a general low overall importance for invasion success. Instead, alternative individual lifehistory trajectories appear to determine invasion success. This is in line with up to 15% of all specimens having outlying biological trait values of potential adaptive value, suggesting a considerable importance of adaptive trait variation among single individuals for the whole invasion progress. This "individual trait utility hypothesis" gives an alternative explanation for success of invasive species by single individuals carrying particular traits, and it should be specifically targeted and analyzed at currently invaded sites. K E Y W O R D Saquatic invasive alien species, biological trait variation, individual trait utility hypothesis, local environmental factors, Neogobius melanostomus

A systematic approach to evaluate the influence of environmental conditions on eDNA detection success in aquatic ecosystems

“…The benthic invasive alien round goby Neogobius melanostomus (Teleostei: Gobiidae, Pallas, 1814) is an optimal model species in the context of this study, since it is a globally invasive species in which early detection is particularly important. Moreover, it is characterized by small home ranges, restricted mobility, small body size, little requirements for water quality, and it is well-studied [ 29 , 30 ], including studies on eDNA, i.e. [ 31 ].…”

Invasion strategies in round goby (Neogobius melanostomus): Is bigger really better?

“…However, specific characteristics of propagule itself have hardly been examined [ 12 ]. Characteristics of pioneering invaders may play a key role in determining invasion success as suggested by different abundances of individuals carrying outlying biological traits during the different phases of an invasion [ 13 ].…”

“…With increasing numbers of rapid range expansions, N . melanostomus invasions have been reported from the Laurentian Great Lakes watershed [ 28 – 31 ], from almost the entire Baltic Sea region [ 32 – 34 ] and from many other large European waterbodies, including the Rivers Oder, Elbe, Weser, Rhine [ 35 – 37 ] and the Danube [ 13 , 17 , 19 , 38 – 40 ]. Its ongoing rapid spread and its high potential to cause ecological regime-shifts (e.g.…”

“…[ 41 – 44 ]) have accelerated substantial scientific interest in this species worldwide (reviewed in Kornis [ 29 ]). Studies on this species have focused on sampling methods [ 45 ], feeding ecology [ 19 ], parasitology [ 46 ], genetics [ 47 ], morphology [ 38 ], reproduction [ 48 ], plasticity in life history traits [ 17 ], individual performance [ 13 ] and range expansion [ 37 , 40 ] of round goby. However, there is an underrepresentation of studies that have systematically investigated mid- or long-term temporal changes of biological characteristics in N .…”

Invasive round goby Neogobius melanostomus has sex‐dependent locomotor activity and is under‐represented in catches from passive fishing gear compared with seine catches

“…The sex specific locomotory activity in invasive N. melanostomus has important implications for its range expansion and dispersal. In accordance with the “individual trait utility hypotheses” (Cerwenka et al ., ) the individuals with higher performance significantly contribute to invasion success. Attaining high performance is possibly related to high locomotory activity and more active individuals invade new areas sooner (Thorlacius et al ., ).…”