Find research datasets worth reusing

Fig. 9 in The non-native freshwater fishes of Singapore: an annotated compilation

Fig. 9. Scleropages jardini, ca. 350 mm SL, trade material.

Fig. 6 in The non-native freshwater fishes of Singapore: an annotated compilation

Fig. 6. Notopterus notopterus, ca. 250 mm SL, Tengeh Reservoir.

Fig. 5. Chitala ornata, 650 in The non-native freshwater fishes of Singapore: an annotated compilation

Fig. 5. Chitala ornata, 650 mm SL, Pandan Reservoir.

Fig. 4. Arapaima gigas, 181.2 in The non-native freshwater fishes of Singapore: an annotated compilation

Fig. 4. Arapaima gigas, 181.2 mm SL, trade material.

Fig. 2 in The non-native freshwater fishes of Singapore: an annotated compilation

Fig. 2. Atractosteus spatula, ca. 1,200 mm SL, Bedok Reservoir.

Fig. 90. Herichthys carpintis, 210 in The non-native freshwater fishes of Singapore: an annotated compilation

Fig. 90. Herichthys carpintis, 210 mm SL, Sungei Buloh.

opencc-zeroSep 2021View details →

A non-native earthworm shifts the seed predation dynamics of a native weed

Seed predators both consume and disperse seeds, with important consequences for the population dynamics of many plant species. The net effect of multiple seed predators depends on the relative proportion of the seed pool each predator obtains, and this proportion should reflect species-specific habitat preferences. We studied the effect of the non-native earthworm, Lumbricus terrestris, on seed loss dynamics in the native weed, Ambrosia trifida (giant ragweed). Giant ragweed seeds are predated by mice, but L. terrestris may protect the seeds against rodent predation by caching them in its burrows. We investigated these interactions, as well as how environmental factors affected net seed losses by competing seed predators. A two-year field study was conducted in which we measured removal of experimentally dispersed giant ragweed seeds by earthworms and mice in habitats varying in plant cover. We analyzed the relative proportion of seeds taken by each species under the varying experimental conditions. Species-specific responses to abiotic conditions and plant cover drove variation in the share of seeds taken by earthworms versus mice, with earthworms gaining relatively more seeds under warmer, wetter conditions and low plant cover habitats, and mice obtaining more seeds under colder, drier conditions and high plant cover habitats. Plant cover and weather conditions also determined which predator species accessed seeds first, and this conferred a competitive advantage that was compounded over time. Earthworms cached some seeds under all experimental conditions, suggesting that L. terrestris can act mutualistically with giant ragweed by making seeds inaccessible to rodent seed predators. Synthesis and applications. Our results support the view that interactions among the environment and competing seed predators determine the fate of seed pools. The data also support the hypothesis that L. terrestris facilitates giant ragweed by competing with mice for giant ragweed seeds, likely contributing to its spread across the landscape and hindering effective weed management. Lumbricus terrestris is prevalent throughout temperate regions and may similarly affect seed predation dynamics of other large-seeded species, impacting plant communities across a range of habitats.

opencc-zeroOct 2022View details →

Environmental-related variation of stoichiometric traits in body and organs of non-native sailfin catfishes Pterygoplichthys spp.

Intraspecific variation in stoichiometric traits was thought to be an adaptive response to reduce the elemental imbalance between organisms and diet in the habitat. Studying the spatial variation of stoichiometric traits of non-native species and the factors contributing to the variation could help to better understand the invasion mechanism of non-native fish. In this study, stoichiometric traits (i.e. carbon [C], phosphorus [P], calcium [Ca] and their ratios) variation in the body and organs of non-native sailfin catfishes Pterygoplichthys spp. were investigated across 13 river sections in the main river basins of south China. The relationships between environmental factors and stoichiometric traits were analyzed using a general linear model and an information-theoretic approach. A manipulated feeding experiment was conducted to investigate the impact of food quality on the stoichiometry of sailfin catfishes in a greenhouse. Sailfin catfishes exhibited considerable variability in body and organ elemental composition. Site identity was the main factor contributing to the variation, which could be explained by a combination of environmental factors including climate, diet quality, fish species richness, and trophic status in the invaded rivers. Water chemistry (i.e. total nitrogen and phosphorus, ammonia nitrogen, and soluble reactive phosphorus) contributed to the most variation of stoichiometric traits. Imbalances of P and Ca between sailfin catfishes and food resources varied among sampling sites, reflecting the spatial heterogeneity of nutrient limitation. Juvenile sailfin catfishes exhibited stoichiometric homeostasis (0<1/H<0.25) for all elemental contents and ratios in the feeding experiment. These findings suggested variation in stoichiometric traits of sailfin catfishes might be attributed to the changes in elemental metabolism to cope with context-specific environments. This study provided heuristic knowledge about environmental-related variation in stoichiometric traits, which could enhance the understanding of the non-native species' adaptation to resource fluctuation in the invaded ecosystems.

opencc-zeroNov 2022View details →

Fluctuations in resource availability shape the competitive balance among non-native plant species

Fluctuating resource availability plays a critical role in determining non-native plant invasions by mediating the competitive balance between non-native and native species. However, the impact of fluctuating resource availability on interactions among non-native species remains largely unknown. This represents a barrier to understanding invasion mechanisms, particularly in habitats that harbor multiple non-native species with different responses to fluctuating resource availability. To examine the responses of non-native plant species to nutrient fluctuations, we compared the growth of each of 12 non-native species found to be common in local natural areas to nutrients supplied at a constant rate or supplied as a single large pulse in a pot experiment. We found that seven species produced more biomass with pulsed nutrients compared to constant nutrients (hereafter 'benefitting species'), while the other five species did not differ between nutrient enrichment treatments (hereafter 'non-benefitting species'). To investigate how nutrient fluctuations influence the interactions among non-native plant species, we established experimental non-native communities in the field with two benefitting and two non-benefitting non-native species. Compared with constant nutrient supply, the single large pulse of nutrients did not influence community biomass, but strongly increased the biomass and cover of the benefitting species and decreased those of the non-benefitting species. Furthermore, the benefitting species had higher leaf N content and greater plant height when nutrients were supplied as a single large pulse than at a constant rate, whereas the non-benefitting species showed no differences in leaf N content and were shorter when nutrients were supplied as a single large pulse than at a constant rate. Our results add to the growing evidence that the individual responses of non-native species to nutrient fluctuation are species-specific. More importantly, benefitting species were favored by nutrients coming in a pulse, while non-benefitting ones were favored by nutrients coming constantly when they grew together. This suggests that nutrient fluctuations can mediate the competitive balance among non-native plants and may thus determine their invasion success in a community harbouring multiple non-native plant species.

opencc-zeroDec 2022View details →

Diet overlap among non-native trout species and native Cutthroat Trout (Oncorhynchus clarkii) in two U.S. ecoregions

The invasion of freshwater ecosystems by non-native species can constitute a significant threat to native species and ecosystem health. Non-native trouts have long been stocked in areas where native trouts occur and have negatively impacted native trouts through predation, competition, and hybridization. This study encompassed two seasons of sampling efforts across two ecoregions of the western United States: The Great Basin in summer 2016 and the Yellowstone River Basin in summer 2017. We found significant dietary overlaps among native and non-native trouts within the Great Basin and Yellowstone River Basin ecoregions. Three orders of invertebrates (Ephemeroptera, Trichoptera and Diptera) composed the majority of stomach contents and were responsible for driving the observed patterns. Great Basin trout had higher body conditions (k) and non-native Great Basin trout had higher gut fullness values than Yellowstone River Basin trout, indicating a possible limitation of food in the Yellowstone River Basin. Native fishes were the least abundant and had the lowest body condition in each ecoregion. These findings may indicate a negative impact on native trouts by non-native trouts. We recommend additional monitoring of native and non-native trout diets, regular invertebrate surveys to identify the availability of diet items, and reconsidering stocking efforts that can result in overlap of non-native fishes with native cutthroat trout.

Figure 3 in Non-native freshwater fish from drainages of Rio Grande do Sul State, Brazil

Figure 3. Total number of records of exotic species by drainage basin cataloged in scientific collections between 1965 and 2020. No records were found in scientific collections for the big-headed carp Hypophthalmichthys molitrix.

Figure 12 in Non-native freshwater fish from drainages of Rio Grande do Sul State, Brazil

Figure 12. Serrasalmus maculatus (Palometa), UFRGS 28800, 75.1 mm SL, arroio dos Lourenços, tributary of the Rio Vacacaí, Laguna dos Patos system. Photo: Juliano Ferrer.

Figure 7 in Non-native freshwater fish from drainages of Rio Grande do Sul State, Brazil

Figure 7. Distribution of records of Acestrorhynchus pantaneiro in Río Uruguay, Laguna dos Patos and Rio Tramandaí basins.

Figure 11 in Non-native freshwater fish from drainages of Rio Grande do Sul State, Brazil

Figure 11. Number of records of allochthonous species Trachelyopterus lucenai recorded over the years in the Laguna dos Patos (SLP) and Rio Tramandaí (TRA) systems according to scientific collections databases. PR = First published record for the Rio Tramandaí system (Schifino et al., 2004).

Figure 16 in Non-native freshwater fish from drainages of Rio Grande do Sul State, Brazil

Figure 16. Number of records of exotic fish species introduced in Brazil according to scientific collections databases.

Figure 14 in Non-native freshwater fish from drainages of Rio Grande do Sul State, Brazil

Figure 14. Number of records of the ten exotic species found in Brazil by de- Figure 15. Number of records per decade between 1960 and 2020 of the cades between 1960 and 2020 according to scientific collections databases. two exotic species with the highest number of records in scientific collections.

Figure 9 in Non-native freshwater fish from drainages of Rio Grande do Sul State, Brazil

Figure 9. Number of records of allochthonous species Acestrorhynchus pantaneiro recorded over the years in the Laguna dos Patos (SLP) and Rio Tramandaí (TRA) systems according to scientific collections databases.

Figure 13 in Non-native freshwater fish from drainages of Rio Grande do Sul State, Brazil

Figure 13. Number of records of exotic species by Brazilian states according to scientific collections databases.

Figure 5 in Non-native freshwater fish from drainages of Rio Grande do Sul State, Brazil

Figure 5. Piaractus mesopotamicus (pacu) MCN 17139, 201.0 mm SL, between the mouth of the Rio Gravataí and the Ilha Humaitá, Delta of the Rio Jacuí, Laguna dos Patos system. Photo: Vinicius A. Bertaco.

Figure 4 in Non-native freshwater fish from drainages of Rio Grande do Sul State, Brazil

Figure 4. Total number of records of exotic fish species cataloged in scientific collections between 1965 and 2020.