Factors associated with the population structure of an invasive mollusk in a neotropical floodplain

Abstract

Limnoperna fortunei is an invasive mussel species that is continuously expanding through South American. It has five larval stages, which usually differ in tolerance to environmental factors. How different abiotic filters affect L. fortunei larval stages has not been studied in depth. We employed a detailed database describing five floodplain environments to investigate the distribution of L. fortunei larval stages within and among these environments and determine which local abiotic filters affect the density of each larval stage. We found that the two youngest larval stages accounted for up to 83% of the larval density in four of the five environments studied, confirming an expanding population pyramid of L. fortunei in these environments. We also found positive and negative relationships among abiotic filters, and these relationships affected, directly and indirectly, the density of the youngest larval stages. Turbidity, water level, and suspended inorganic matter directly decreased the density of the two youngest larval stages. Conversely, temperature and pH directly increased the density of D-shaped and umbonated stages, respectively. Additionally, water level indirectly increased the density of the youngest larval stages mediated by declines in turbidity and suspended inorganic matter. Our findings suggest a likely expansion of L. fortunei in the Upper Paraná Floodplain. However, local abiotic filters, such as turbidity, water level, and suspended inorganic matter, decrease the density of the youngest larval stages. This finding illustrates that the establishment of L. fortunei can be prevented mainly if the youngest larval stages are controlled.

High‐latitude invasion and environmental adaptability of the freshwater mussel Limnopernafortunei in Beijing, China

“…Our findings for high‐latitude Beijing indicate that water temperature positively affects D‐shaped veliger and pediveliger density (Appendix S1: Tables S3 and S4). This effect may reflect the relationship between reproductive synchrony of L. fortunei and environmental seasonality (Ernandes‐Silva et al, 2021; Junk et al, 1989). For example, in southern China, Japan, and Argentina, L. fortunei reproduction reaches a peak in early summer when the water temperature rises (i.e., from 19 to 22°C, from 15 to 20°C, and from 16.7 to 18°C, respectively) (Boltovskoy, 2015; Lee, 2014; Nakano et al, 2017).…”

“…We used a YSI EXO water‐quality monitoring instrument (Xylem, USA) to measure water‐quality parameters (water temperature [WT], conductivity [Cond], pH, DO, and turbidity [Turb]) that may affect L. fortunei 's survival and development (Ernandes‐Silva et al, 2021; Oliveira et al, 2011). A portable chlorophyll fluorometer (Seabird, USA) was used to measure chlorophyll a (Chl a ).…”

“…Generally, adult L. fortunei exhibits strong adaptability to a wide range of variations in environmental conditions, including pH, calcium concentration, and conductivity (Boltovskoy, 2015; Liu et al, 2020), whereas the veligers are less tolerant to variations in environmental conditions (e.g., Zhang et al, 2017). Moreover, the four veliger stages (D‐shaped veliger, umbonated veliger, pediveliger, and plantigrade veliger) exhibit different tolerances to environmental stress (Ernandes‐Silva, Ragonha, Jati, & Takeda, 2016; Ernandes‐Silva, Ragonha, Rodrigues, & Mormul, 2016; Ernandes‐Silva et al, 2021; Liu et al, 2017). Early D‐shaped and umbonated veligers are sensitive to some abiotic stresses (e.g., high turbidity, high salinity, low DO); thus, abiotic factors may exert a filtering effect on these larval stages in some water bodies (Darrigran et al, 2011; Ernandes‐Silva et al, 2021; Oliveira et al, 2011).…”

“…L. fortunei colonization of structures along the middle and north sections of the M-SNWTP (e.g., Henan and Hebei provinces), with adult attachment density occasionally exceeding 10,000 ind m −2 , has been reported (Zhao et al, 2019). Reasoning from the mean fertility value of L. fortunei (~1000 eggs per adult; Ernandes-Silva et al, 2021), millions of veligers may have been conveyed downstream. Beijing is the terminal of the M-SNWTP.…”

“…Moreover, the four veliger stages (D‐shaped veliger, umbonated veliger, pediveliger, and plantigrade veliger) exhibit different tolerances to environmental stress (Ernandes‐Silva, Ragonha, Jati, & Takeda, 2016; Ernandes‐Silva, Ragonha, Rodrigues, & Mormul, 2016; Ernandes‐Silva et al, 2021; Liu et al, 2017). Early D‐shaped and umbonated veligers are sensitive to some abiotic stresses (e.g., high turbidity, high salinity, low DO); thus, abiotic factors may exert a filtering effect on these larval stages in some water bodies (Darrigran et al, 2011; Ernandes‐Silva et al, 2021; Oliveira et al, 2011). Later‐stage veligers gradually become insensitive to abiotic stresses but sensitive to food sources (e.g., phytoplankton biomass; Ernandes‐Silva, Ragonha, Jati, & Takeda, 2016; Ernandes‐Silva, Ragonha, Rodrigues, & Mormul, 2016).…”