Zealand Mud Snail Research Articles

Chemical variables predicting colonization risk of the invasive New Zealand mudsnail (Potamopyrgus antipodarum) in Pennsylvania’s flowing waters

Chemical variables predicting colonization risk of the invasive New Zealand mudsnail (Potamopyrgus antipodarum) in Pennsylvania’s flowing waters

Establishment and ecological integration of the New Zealand mud snail in Spirit Lake, Mount St. Helens, Washington State, USA

Establishment and ecological integration of the New Zealand mud snail in Spirit Lake, Mount St. Helens, Washington State, USA

Potamopyrgus antipodarum (Gastropoda: Tateidae) in central Chile: new records, reproductive output assessment, and coexistence with native species

ABSTRACT Three new populations of the invasive New Zealand mud snail, Potamopyrgus antipodarum, have been discovered in central Chile, increasing the documented records in the country to 23. Only females were observed in the present study. Significant differences in shell length and fecundity were found among populations. The size of the snails was less than 6 mm, while fecundity varied from 0 to 45 offspring per snail. A significant correlation was found between adult shell length and brood size in one of the three populations discovered. In these localities, Potamopyrgus antipodarum coexists with native and possibly other invasive gastropods.

Invasive freshwater snails are less sensitive to population density than native conspecifics.

Understanding how and why some species or lineages become invasive is critically important for effectively predicting and mitigating biological invasions. Here, we address an important unanswered question in invasion biology: do key life-history traits of invasive versus native lineages within a species differ in response to key environmental stressors? We focus on the environmental factor of population density, which is a fundamental characteristic of all populations, and investigate how changes in density affect native versus invasive Potamopyrgus antipodarum (New Zealand mudsnail). P. antipodarum has invaded 39 countries and detrimentally affects invaded environments. Previous studies of native and invasive populations and from laboratory experiments have demonstrated that growth and reproduction of P. antipodarum is sensitive to population density, though whether and how this sensitivity varies across native versus invasive lineages remains uncharacterized. We quantified individual growth rate and reproduction in P. antipodarum from multiple distinct native and invasive lineages across three different population density treatments. The growth of native but not invasive lineages decreased as density increased. There was no differential effect of density treatment on embryo production of invasive versus native snails, but a significantly higher proportion of snails were reproductive in high density compared to intermediate density for invasive lineages. In native lineages, there were no significant differences in the relative frequency of reproductive snails across density treatments. While the extent to which these results from our laboratory study can be extrapolated to the more complex natural world remain unclear, our findings are consistent with a scenario where differential sensitivity to population density could help explain why some lineages become successful invaders. Our findings also align with previous studies that show that invasive P. antipodarum lineages exhibit a relatively wide range of tolerance to environmental stressors.

Invasion dynamics of New Zealand mud snail (Potamopyrgus antipodarum) in the Laurentian Great Lakes

Invasion dynamics of New Zealand mud snail (Potamopyrgus antipodarum) in the Laurentian Great Lakes

Multiple stressors mediate the effects of warming on leaf decomposition in a large regulated river

AbstractPredicting how increasing temperatures interact with other global change drivers to influence the structure and dynamics of Earth's ecosystems is a primary challenge in ecology. Our study made use of multiple simultaneous “natural experiments” to examine how rapid warming, declining nutrients, invasive consumers, and riparian invasive species management interact to influence leaf decomposition in a large and regulated river. Specifically, we compared the breakdown of cottonwood (Populus fremontii), willow (Salix exigua), and saltcedar (Tamarix sp.) leaf litter in 2022 to a previous experiment from 1998 that occurred under much cooler water temperatures, and had higher water phosphorus concentrations, low numbers of invasive New Zealand mudsnails (Potamopyrgus antipodarum), and unaltered litter chemistry from the herbivory of saltcedar leaf beetles (Diorhabda carinulata). We found that the effects of up to 10°C warmer temperatures on leaf decomposition were mediated by the establishment and management of invasive species and declining water nutrient concentrations arising from upstream reservoir lowering. Such interactions led to accelerated breakdown of saltcedar, but relatively minor effects of warming on the rate of cottonwood and willow decomposition. Additionally, our results demonstrate the potential for favorable invasive species management outcomes in the terrestrial environment to produce unintended responses in adjacent freshwater ecosystems. As temperatures continue to rise, it is critical that future studies consider how warming interacts with multiple stressors and environmental factors to influence processes such as decomposition in freshwater ecosystems.

The expansion and establishment of the New Zealand mud snail Potamopyrgus antipodarum (Gray, 1843) in the freshwater ecosystems of Madeira Island (NE Atlantic)

The expansion and establishment of the New Zealand mud snail Potamopyrgus antipodarum (Gray, 1843) in the freshwater ecosystems of Madeira Island (NE Atlantic)

Benthic macroinvertebrate community structure in nutrient‐rich, spring‐fed streams recently invaded by non‐native New Zealand mud snails

Abstract Ecological roles of non‐native species can vary over space and time due to abiotic factors and characteristics of the invaded communities. For instance, nutrient availability, temperature, and flow regime can influence invasion outcomes in freshwaters. This variability makes it challenging to predict non‐native species' effects in newly introduced areas. New Zealand mud snails (Potamopyrgus antipodarum; NZMS) are among the most widespread aquatic invasive species globally and have recently been detected in highly productive, spring‐fed streams in the upper mid‐west U.S.A. that are important trout fisheries. We hypothesised that the nutrient‐rich, thermally stable groundwater‐fed streams would provide favourable conditions for NZMS populations, potentially amplifying their effects on native communities. We surveyed benthic macroinvertebrate community structure at 10 streams representing a gradient of NZMS densities in the Driftless Area of southern Wisconsin. At five of the streams, we quantified temporal variation in NZMS and other benthic macroinvertebrates over three seasons. NZMS populations varied considerably across sites and over time, ranging from a few hundred to over 70,000 snails/m2. NZMS numerically represented as much as 97% of the invertebrate community at the highest density sites. At two sites, NZMS increased in population density by 50‐fold and 22‐fold over the survey duration, while at other sites their densities were relatively constant. Based on a principal components analysis summarising stream environmental variables, NZMS densities were negatively associated with stream discharge and positively associated with nitrogen and phosphorus concentrations. The total density and biomass of all benthic invertebrates, and Ephemeroptera and Amphipoda in particular, were negatively associated with NZMS density and biomass. Based on multivariate analyses, overall benthic community composition differed based on NZMS invasion status, as well as across seasons. These results suggest that the environments of southern Wisconsin spring‐fed streams provide favourable conditions for NZMS populations, allowing them to dominate some benthic communities. NZMS effects are likely to vary strongly across streams and over time within streams, highlighting the importance of future work to mechanistically test biotic and abiotic factors influencing their abundance.

Population influences desiccation tolerance in an invasive aquatic snail, Potamopyrgus antipodarum (Tateidae, Mollusca).

Traits in species that influence invasion success may vary in populations across its invaded range. The aquatic New Zealand mud snail, Potamopyrgus antipodarum, reproduces parthenogenetically in its invaded range, and a few distinct clonal genotypes have been identified in North America. Much of the spread of the snail in North America has been the result of unintentional overland transport by recreational water users. Thus, desiccation tolerance may play an important role in the invasion success of this species. The primary goal of these experiments is to determine if variation in desiccation tolerance exists between populations of this species. Here we compared multiple multi-locus genotypes (MLGs) and populations within those genotypes with regard to their desiccation tolerance. We conducted three experiments. The first compared the survival rate over time of snails from three populations and two MLGs with regard to their ability to survive being completely removed from water. The second experiment examined different size classes of snails from the same population, and the third experiment compared four different populations and two MLGs genotypes with respect to their survival rate over time when removed from water but being kept in moist conditions. We found larger snails tolerate desiccation longer than smaller snails with snails between 4 and 4.6 mm surviving at a rate of more than 50% after 12 h while smaller snails survived at a less than 5% rate after 12 h. We also found significant variation both between and within MLGs in their survival rate when completely removed from water and dried with the MLG from the western US having a more than 50% greater survival probability than the eastern MLGs at both 18 and 24 h out of water. When removed from water and kept moist all MLGs had a near 100% survival rate at 60 days at 7 °C, and most survived at a greater than 90% rate at 60 days at 17 °C, while no MLG's survived past 30 days at 27 °C. The results demonstrate that variation for desiccation tolerance exists between populations of this invader which could influence the invasiveness of different populations.

Periphyton growth on allochthonous input in streams may lead to higher individual growth rates of the invasive New Zealand mud snail (<em>Potamopyrgus antipodarum</em>)

The aquatic, invasive New Zealand mud snail (Potamopyrgus antipodarum) exploits a variety of food sources. Here we examine the change in growth of snails that fed on periphyton colonizing leaf litter, wood, rock, and a control. Juveniles were grown in the lab on Spirulina algae powder (control) or periphyton grown on rock, leaf litter, or wood. Length was measured at the beginning of the experiment and after eight weeks. Snails grown on leaf litter increased in length more than twice as much as the control and the snails in the rock treatment, and the snails grown on wood showed an increase in length more than twice as much as snails in the rock treatment. This suggests that allochthonous material may contribute to a more nutritious food source for New Zealand mud snails and possibly aid in their invasion success.

Interactions between invasive New Zealand mudsnails and leaf litter: growth and decomposition

Interactions between invasive New Zealand mudsnails and leaf litter: growth and decomposition

Field surveys reveal physicochemical conditions promoting occurrence and high abundance of an invasive freshwater snail (Potamopyrgus antipodarum)

Environmental conditions promoting the occurrence and high abundance of non-native taxa are linked to critical stages of species invasions: establishment, whether a site can sustain a population of the non-native taxon, and impact, the extent to which the consequences of establishment negatively affect the invaded ecosystem. Using surveys across environmental gradients, we examined the physicochemical conditions associated with the occurrence and abundance of the invasive New Zealand mudsnail (Potamopyrgus antipodarum) and co-occurring native mollusks. Abundance of Potamopyrgus very strongly increased with stream width and conductivity (specifically with chloride, sulfate, potassium, and sodium ions). Also, Potamopyrgus were most likely to occur at sites with relatively low pH and water velocity and relatively high calcium ion concentration and abundance also slightly increased in these conditions. The physicochemical conditions indicate the characteristics of sites that are suitable for establishment and secondary spread of Potamopyrgus. Native mollusks differed from Potamopyrgus in the physicochemical conditions associated with abundance suggesting that variation among habitats could permit native mollusks to persist at larger geographic scales even if they often co-occur with Potamopyrgus. Abundance of native Physa moderately decreased with abundance of Potamopyrgus. Because abundance of Physa and Potamopyrgus responded oppositely to stream width and conductivity, the negative relationship between the abundance of these two taxa may be caused by contrasting responses to physicochemical conditions, acting alone or in concert with biotic interactions.

First Records of the Invasive New Zealand Mudsnail (Potamopyrgus antipodarum) in the Potomac River Basin

The distribution of invasive Potamopyrgus antipodarum (New Zealand Mudsnail [NZM]) is relatively limited in eastern North America, with populations known in the Great Lakes basin and scattered locations in several Atlantic Slope drainages. Herein, we report the first documented occurrence of NZM in the Potomac River basin, based on collections at 2 adjacent sites in Falling Spring Branch, Franklin County, PA. We speculate the species was introduced into Falling Spring Branch via fishing gear from Susquehanna River basin tributaries in adjacent Cumberland County where there are documented NZM populations.

Sigmoidal curves reflect impacts and dynamics of aquatic invasive species

Identifying general patterns and trends underlying the impacts and dynamics of biological invasions has proven elusive for scientists. Recently, the impact curve was proposed as a means to predict temporal impacts of invasive alien species, characterised by a sigmoidal growth pattern with an initial exponential increase, followed by a subsequent rate of decline and approaching a saturation level in the long-term where impact is maximised. While the impact curve has been empirically demonstrated with monitoring data of a single invasive alien species (the New Zealand mud snail, Potamopyrgus antipodarum), broadscale applicability remains to be tested for other taxa. Here, we examined whether the impact curve can adequately describe the invasion dynamics of 13 other aquatic species (within Amphipoda, Bivalvia, Gastropoda, Hirudinea, Isopoda, Mysida, and Platyhelminthes) at the European level, employing multi-decadal time series of macroinvertebrate cumulative abundances from regular benthic monitoring efforts. For all except one tested species (the killer shrimp, Dikerogammarus villosus), the sigmoidal impact curve was strongly supported (R2 > 0.95) on a sufficiently long time-scale. For D. villosus, the impact had not yet reached saturation, likely reflecting the ongoing European invasion. The impact curve facilitated estimation of introduction years and lag phases, as well as parameterisation of growth rates and carrying capacities, providing strong support for the boom-bust dynamics typically observed in several invader populations. These findings suggest that impact can grow rapidly before saturating at a high level, with timely monitoring often lacking for the detection of invasive alien species post-introduction. We further confirm the applicability of the impact curve to determine trends in invasion stages, population dynamics, and impacts of pertinent invaders, ultimately helping inform the timing of management interventions. We hence call for improved monitoring and reporting of invasive alien species over broad spatio-temporal scales to permit further testing of large-scale impact consistencies across various habitat types.

Effects of the invasive aquatic snail Potamopyrgus antipodarum (Gray, 1853) on ecosystem properties and services

AbstractEcosystems provide benefits to humans, including provisioning, regulating, and cultural services. However, invasive species can threaten ecosystem well-functioning and services provided. One invasive species with such potential is the New Zealand mud snail (NZMS) Potamopyrgus antipodarum. The aims of this study are focused on the quantitative review of (1) the NZMS impacts on ecosystem properties and their direct links with ecosystem services, and (2) the ecosystem services that can be affected by the NZMS. The high density reached by this species in most of the invaded ecosystems and its highly competitive ability affect ecosystem structure and functioning. However, some facilitation processes on native species may result in an improvement of some services. The NZMS tends to positively affect cultural services (88% positive cases) but negatively to provisioning services (77% of cases). Regarding, regulating and maintenance services, the proportions of positive and negative effects were similar (45% vs 36%, respectively). Therefore, the NZMS is a species with numerous negative impacts on ecosystem services. However, ecosystem services related to health (e.g., dilution effect against parasites) and research (e.g., biomonitoring) are cultural services that the NZMS can improve. No economic assessment of the impacts of the NZMS is available in the literature.

Stay in shape: Assessing the adaptive potential of shell morphology and its sensitivity to temperature in the invasive New Zealand mud snail Potamopyrgus antipodarum through phenotypic plasticity and natural selection in Europe.

Climate change may force organisms to adapt genetically or plastically to new environmental conditions. Invasive species show remarkable potential for rapid adaptation. The ovoviviparous New Zealand mud snail (NZMS), Potamopyrgus antipodarum, has successfully established across Europe with two clonally reproducing mitochondrial lineages since its arrival in the first half of the 19th century. Its remarkable variation in shell morphology was shown to be fitness relevant. We investigated the effects of temperature on shell morphology across 11 populations from Germany and the Iberian Peninsula in a common garden across three temperatures. We analyzed size and shape using geometric morphometrics. For both, we compared reaction norms and estimated heritabilities. For size, the interaction of temperature and haplotype explained about 50% of the total variance. We also observed more genotype by environment interactions indicating a higher degree of population differentiation than in shape. Across the three temperatures, size followed the expectations of the temperature‐size rule, with individuals growing larger in cold environments. Changes in shape may have compensated for changes in size affecting space for brooding embryos. Heritability estimates were relatively high. As indicated by the very low coefficients of variation for clonal repeatability (CV A ), they can probably not be compared in absolute terms. However, they showed some sensitivity to temperature, in haplotype t more so than in z, which was only found in Portugal. The low CV A values indicate that genetic variation among European populations is still restricted with a low potential to react to selection. A considerable fraction of the genetic variation was due to differences between the clonal lineages. The NZMS has apparently not been long enough in Europe to accumulate significant genetic variation relevant for morphological adaptation. As temperature is obviously not the sole factor influencing shell morphology, their interaction will probably not be a factor limiting population persistence under a warming climate in Europe.

A miniaturized electrothermal array for rapid analysis of temperature preference behaviors in ecology and ecotoxicology

Due to technical limitations, there have been minimal studies performed on thermal preferences and thermotactic behaviors of aquatic ectotherm species commonly used in ecotoxicity testing. In this work, we demonstrate an innovative, purpose-built and miniaturized electrothermal array for rapid thermal preference behavioral tests. We applied the novel platform to define thermal preferences in multiple invertebrate and vertebrate species. Specifically, Dugesia notogaea (freshwater planarians), Chironomus tepperi (nonbiting midge larvae), Ostracoda (seed shrimp), Artemia franciscana (brine shrimp), Daphnia carinata (water flea), Austrochiltonia subtenuis (freshwater amphipod), Physa acuta (freshwater snail), Potamopyrgus antipodarum (New Zealand mud snail) and larval stage of Danio rerio (zebrafish) were tested. The Australian freshwater water fleas, amphipods, snail Physa acuta as well as zebrafish exhibited the most consistent preference to cool zones and clear avoidance of zones >27 °C out of nine species tested. Our results indicate the larval stage of zebrafish as the most responsive species highly suitable for prospective development of multidimensional behavioral test batteries. We also showcase preliminary data that environmentally relevant concentrations of pharmaceutical pollutants such as non-steroidal anti-inflammatory drug (NSAID) ibuprofen (9800 ng/L) and insecticide imidacloprid (4600 ng/L) but not anti-depressant venlafaxine (2200 ng/L) and (iv) anticonvulsant medications gabapentin (400 ng/L) can perturb thermal preference behavior of larval zebrafish. Collectively our results demonstrate the utility of simple and inexpensive thermoelectric technology in rapid exploration of thermal preference in diverse species of aquatic animals. We postulate that more broadly such technologies can also have added value in ecotoxicity testing of emerging contaminants.

Coupling Gear Decontamination Trials and Angler Surveys to Minimize Spread of Invasive New Zealand Mud Snails Potamopyrgus antipodarum

AbstractThe New Zealand mud snail Potamopyrgus antipodarum (NZMS) is a global invader that is readily spread through attachment to recreational fishing gear. Preventing the spread of NZMSs by decontaminating fishing gear such as waders is a key step toward limiting invasive NZMSs and their ecological impacts; however, the effectiveness of decontamination protocols depends on both the efficacy of the protocol and the willingness of anglers to implement it. We tested the efficacy of three decontaminants (Virkon Aquatic, Formula 409, and bleach) at killing NZMSs on waders using two application techniques (spray versus soak) and two exposure durations (10 versus 20 min). We coupled the results of these tests with responses to a self‐administered online survey that gauged the willingness of anglers to implement several decontamination strategies. Mortality of NZMSs differed widely among decontaminants, with the greatest mortality caused by Formula 409 (mean ± SE = 100 ± 0%), regardless of application type or duration. Bleach produced a mean mortality of 68.75 ± 11.97%, and Virkon Aquatic resulted in a mean mortality of 56.25 ± 11.97%. Neither exposure duration nor application method significantly influenced the degree of NZMS mortality, and their interaction was not significant. Anglers who responded to the survey (n = 339) revealed that Formula 409 was the decontaminant they would be most willing to use. Further, spraying was highly preferred over soaking for all decontaminants. Based on our experimental trials and the angler survey, we developed an angler decontamination metric (ADM) that helps to determine the decontamination strategy that optimizes NZMS mortality on fishing gear. Our ADM indicates that spraying gear with Formula 409 is the most effective NZMS decontamination strategy that anglers are willing to use. Our study is the first to combine the efficacy of NZMS decontaminants and angler willingness to adopt a decontamination strategy. By doing so, we hope to encourage the widespread use of NZMS decontamination of fishing gear to limit the spread and impacts of this increasingly relevant invasive species.

Life-history trait variation in native versus invasive asexual New Zealand mud snails.

Potamopyrgus antipodarum is a New Zealand freshwater snail that is invasive worldwide. While native P. antipodarum populations are characterized by frequent coexistence between obligately sexual and obligately asexual individuals, only the asexual snails are known to invade other ecosystems. Despitelow genetic diversity and the absence of sex, invasive asexual P. antipodarum are highly successful. Here, we quantified variation in three key life-history traits across invasive P. antipodarum lineages and compared this variation to already documented variation in these same traits in asexual native lineages to provide a deeper understanding of why some lineages become invasive. In particular, we evaluated if invasive lineages of P. antipodarum could be successful because they represent life-history variation from native ancestors that could facilitate invasion. We found that invasive snails displayed a non-representative sample of native diversity, with invasive snails growing more slowly and maturing more rapidly than their native counterparts. These results are consistent with expectations of a scenario where invasive lineages represent a subset of native variation that is beneficial in the setting of invasion. Together, these results help illuminate the mechanisms driving the worldwide expansion of invasive populations of these snails.

Range Expansion of the Invasive New Zealand Mudsnail (Potamopyrgus antipodarum) in the Susquehanna and Delaware River Basins of Pennsylvania

Abstract New Zealand mudsnails (Potamopyrgus antipodarum; hereafter NZMs) are small (≤6 mm in length) freshwater snails that are considered an invasive species in North America. Invasions of NZMs are typified by high densities of snails, which may cause trophic disruptions by displacing native benthic macroinvertebrates. Although NZMs are previously known from several locations in Pennsylvania, we surveyed 24 streams in the lower/middle Susquehanna River basin and Delaware River basin that were not previously evaluated for the presence of NZMs. We detected three range expansions within the Susquehanna basin and 12 range expansions of NZMs in the Delaware River basin, suggesting that NZMs are more widespread in these regions than was previously known. As many of these locations are popular trout waters, introductions are likely the result of spread on fishing gear.