Phenotypic Shifts in Life History Traits Influence Invasion Success of Goldfish in the Yarlung Tsangpo River, Tibet

Comte

Olden

2017

Aquatic Conservation

Self Cite

1. Freshwater fishes have the distinction of being both a highly imperilled taxonomic group as well as one that has produced many invasive species with widespread ecological impacts. Faced with the difficult task of identifying those species with the greatest need for management action, ecologists have turned to using predictive suites of ecological and life-history traits to provide reasonable estimates of fish invasion and extinction risk. Whether traits associated with invasiveness are the inverse of those associated with imperillment, known as the 'two-sides-of-the-same-coin' hypothesis, remains unclear. 2.A global trait analysis (including maximum total body size, longevity, size at maturation, age at maturation, fecundity and egg size) for 6293 freshwater fishes was conducted to examine the trait correlates of species proneness to invasion or extinction. A meta-analytical procedure was deployed using univariate and multivariate trait analyses that accounted for the effects of shared phylogeny.3. Mean trait differences (measured as Hedges' d effect size) were found between invasive and threatened species when compared with native species, thus supporting the two-sides-ofthe-same-coin hypothesis for freshwater fish. Invasive species were characterized by larger body size, greater longevity, delayed maturation and higher fecundity than threatened species. Furthermore, invasive species were found to display greater trait variability compared with threatened species, suggesting that different traits may be selected at different stages of the invasion process (from pathway entrainment to establishment) whereas more specific trait combinations may predispose species to higher extinction risk.4. The present study demonstrated a strong trait basis to global-scale invasion risk and extinction vulnerability for freshwater fishes. Given that both time and resources are too limited for detailed species-by-species assessments, the results suggest that trait correlates provide a reasonable estimate of invasion and extinction risk that can inform more targeted and proactive conservation strategies.

Section: Discussionmentioning

confidence: 99%

Heads you win, tails you lose: Life‐history traits predict invasion and extinction risk of the world's freshwater fishes

Comte

Olden

2017

Aquatic Conservation

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“…Yan & Chen, 2007Chen et al, 2009;Liu et al, 2015). Many native species from western basins are considered as periodic life history strategists (e.g.…”

Section: Discussionmentioning

confidence: 99%

“…By contrast, most non-native species exhibit opportunistic strategies with rapid growth and early maturation (e.g. Yan & Chen, 2007Chen et al, 2009;Liu et al, 2015). Vacant niche opportunities may increase the probability of successful establishment of non-native species and consequently lead to greater homogenization (also see Sk ora et al, 2015).…”

Section: Discussionmentioning

confidence: 99%

Species invasions threaten the antiquity of China's freshwater fish fauna

Diversity and Distributions

Chen

et al. 2017

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Aim Human-mediated species introductions and extirpations have resulted in the homogenization of biotas over time. However, there remains considerable uncertainty in our understanding of homogenization process for megadiverse regions of the world. Here, we investigate the consequences of widespread species invasions and extirpations for the biogeography of China's unique freshwater fish fauna. Location China.Methods By assembling a comprehensive dataset for distribution of Chinese freshwater fishes, we quantify how non-native fish species, from both overseas introductions and domestic translocations, has led to taxonomic homogenization of fish faunas at watershed, basin, ecoregion and country scales. We explore how the observed patterns in homogenization vary geographically, and identify those species most responsible for the faunal changes. Lastly, we simulate how China's fish fauna may continue to homogenize according to different scenarios of anticipated species introductions and extirpations. Results We demonstrate that species introductions and extirpations have homogenized freshwater fish faunas across China. Overall compositional similarity of watersheds increased by 7.0% (from a historical 14.9% to 21.9% in the present day; Sørensen index). Compositional similarity of 96 of 103 (93.2%) watersheds increased, with western basins exhibiting the highest magnitude. Translocated non-native species associated with aquaculture practices contributed the most to faunal homogenization when compared to alien species (7.3% and 0.4%, respectively). Furthermore, faunal homogenization is predicted to intensify an additional 0.5-4.2% with increasing numbers of new non-native species introductions and the extirpation of native species.Main conclusions Species introductions and extirpations have resulted in the significant impoverishment, and thus the loss of antiquity, of China's freshwater fish fauna over the past century. In the light of the growing realization that species composition (not richness) defines the role that biodiversity plays in maintaining ecosystem function, our study highlights the need for conservation strategies in China that consider changing patterns of b diversity.

“…Third, variations of intrinsic attributes among populations would also contribute to the difference in early growth. Growth rates of fish are determined by the interplay of phenotypic plasticity and genetic adaptivity ( Conover & Present, 1990 ; Sexton, McKay & Sala, 2002 ; Liu et al, 2015 ). Across the northwestern Pacific Ocean, there might be substantial differences in phenotypic and genetic attributes among populations in Japan, YRE and Taiwan, causing unregular spatial patterns in growth rates.…”

Section: Discussionmentioning

confidence: 99%

Variations in early life history traits of Japanese anchovy Engraulis japonicus in the Yangtze River Estuary

Xian

et al. 2018

PeerJ

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Resources of Japanese anchovy (Engraulis japonicus Temminck & Schlegel, 1846) are undergoing dramatic recessions in China as the consequence of intensifying anthropogenic activities. Elucidating the influences of local-scale environmental factors on early life history traits is of great importance to design strategies conserving and restoring the declining anchovy resources. In this research, we studied hatching date and early growth of anchovy in the Yangtze River Estuary (YRE) using information obtained from otolith microstructure. Onset of hatching season and growth rates of anchovy was compared to populations in Japan and Taiwan. In YRE, the hatching date of anchovy ranged from February 26th to April 6th and mean growth rate ranged from 0.27 to 0.77 mm/d. Anchovies hatching later had higher growth rates than individuals hatching earlier before the 25th day. Among populations, hatching onsets of anchovy from the higher latitude were later than populations in the lower latitude, and growth rates of anchovy in YRE were much lower than populations in Japan and Taiwan. Variations in hatching onsets and early growth patterns of anchovy thus provide important knowledge on understanding the adaptation of anchovy in YRE and designing management strategies on conserving China’s anchovy resources.