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FIG. 1 in Response of American Toads and Their Invertebrate Prey to Experimentally Elevated Soil pH

FIG. 1. Schematic demonstrating the experimental design, location of forest plots within the three study forests, and location of 1 m2 subplots within a forest plot. (A) General layout of the experiment among our three scales of interest: study forest, forest plot, and subplot. (B) Typical arrangement of six forest plots within each of the three study forests. Within each forest, white rectangles represent the three forest plots with untreated, acidified soils while lined rectangles represent the three limetreated, elevated soil pH forest plots. (C) An enlarged example from (B) of one possible random arrangement of the three 1 m2 subplots (light gray boxes; not drawn to scale) located along the perimeter of a forest plot with untreated, acidified soil. Each 1 m2 subplot in each forest plot was assigned to one of three enclosure treatments: a) no enclosure, b) enclosure without American Toads, and c) enclosure with four American Toads.

FIG. 4 in Response of American Toads and Their Invertebrate Prey to Experimentally Elevated Soil pH

FIG. 4. Invertebrate abundances collected on day 0 (A) and day 91 (B) from subplots with three different enclosure treatments (NE ¼ No Enclosures: no enclosures present; NT ¼ No Toads: enclosures present and no toads; T ¼ Toads: enclosures present with toads). Data are mean 6 1 s.e. For each invertebrate grouping where the overall model was significant, enclosure types with the same letter were not different at P, 0.05 from post hoc tests.

FIG. 3 in Response of American Toads and Their Invertebrate Prey to Experimentally Elevated Soil pH

FIG. 3. Non-metric multidimensional scaling (NMDS) ordination of invertebrate community composition on day 0 (A) and day 91 (B). Soil pH treatment group scores and standard errors are represented by symbol type and line type (sites with elevated soil pH—solid shapes, solid line; sites with acidified soils—open shapes, dashed line). Forests are represented by symbol shape (CWRU Farm—circle; Schoop Forest— triangle; Pierson Creek Forest—square).

FIG. 2 in Response of American Toads and Their Invertebrate Prey to Experimentally Elevated Soil pH

FIG. 2. American Toad survival (proportion of initial toads located, n ¼ 4 toads per enclosure initially) and body mass over 90 days within enclosures located in forest plots with elevated soil pH (circles and solid line) and forest plots with acidified soils (triangles and dashed line). (A) Proportion of American Toads located in each enclosure within each soil pH treatment after 25, 60, and 90 days. Data are mean per soil pH treatment at each census period 6 1 s.e. (B) American Toad mass in each enclosure within each soil pH treatment at the start of the study and after 25, 60, and 90 days. Mean toad mass was calculated per enclosure at each census period. Data are mean per soil pH treatment at each census period 6 1 s.e.

Figure 1 in The limits of mtDNA analysis for determining the provenance of invasive species: a midwife toad example

Figure 1. Sampling of the common midwife toad (Alytes obstetricans). Samples from the Netherlands, Belgium and Germany were newly studied. The localities on the coast of the Netherlands (Meijendel and The Hague from top to bottom, enclosed by the pink dotted line) are introductions outside of the native range. Localities are color-coded according to the six major ND4 mtDNA clades, referred to as haplogroups by Gonçalves et al. (2015), to which they belong. Sampling details can be found in supplementary table S1.

Figure 1 in The conservation paradox of an introduced population of a threatened species: spadefoot toads in the coastal dunes of the Netherlands

Figure 1. Sampling sites of the common spadefoot toad (Pelobates fuscus). The main map shows localities sampled outside and the inset localities sampled inside the Netherlands (see main text for details). A rough outline of the natural distribution range in the Netherlands is shaded grey. Localities that contain haplotypes found in the Netherlands are colour coded; otherwise they are left grey (FUS stands for P. fuscus). Sampling details are in supplementary table S1.

Figure 3 in The conservation paradox of an introduced population of a threatened species: spadefoot toads in the coastal dunes of the Netherlands

Figure 3. Haplotype network for the common spadefoot toad (Pelobates fuscus) Haplotypes relevant to the current study are colour coded; the remainder is left grey (details in supplementary table S1). The prefix 'FUS' is not shown for the haplotype codes.

Figure 3 in The limits of mtDNA analysis for determining the provenance of invasive species: a midwife toad example

Figure 3. Median Joining Network of 74 ND4 mtDNA haplotypes of the common midwife toad (Alytes obstetricans). Pie size reflects haplotype frequency and red numbers between parentheses reflect the number of substitutions (if greater than 1). The prefix 'Ao_H' is omitted from haplotype labels. Haplotype details can be found in supplementary table S1.

Figure 2. The 50 in The limits of mtDNA analysis for determining the provenance of invasive species: a midwife toad example

Figure 2. The 50% majority-rule consensus tree from the Bayesian phylogenetic analysis of 74 ND4 mtDNA haplotypes of

Figure 2 in The conservation paradox of an introduced population of a threatened species: spadefoot toads in the coastal dunes of the Netherlands

Figure 2. Phylogenetic tree for common spadefoot toad (Pelobates fuscus) and Pallas's spadefoot toad (P. vespertinus). Haplotypes relevant to the current study are colour coded; the remainder is left grey (details in Table S1). Haplotype abbreviations are: FUS = P. fuscus, VES = P. vespertinus, BAL = P. balcanicus, SYR = P. syriacus, CUL = P. cultripes, and VAR = P. varaldii.

opennotspecifiedJul 2023View details →

Figure 1 in Environmental constraints affect underground reproduction of the common toad (Bufo bufo)

Figure 1. Geographical location of the study area within the Carpathian Mountains (A), The map (fragment) of Peştera cu Apă Cave from Gârliştei Gorges (Aninei Mountains, Romania) showing the breeding areas (BA) location (B).

opencc-by-4.0Nov 2024View details →

Data from: Speciation and historical invasions of the Asian black-spined toad (Duttaphrynus melanostictus)

This data package includes the following datasets analyzed in the corresponding publication:  <ul> <li>An alignment (fasta format) of 130,792 bp concatenating the RAD tags present in at least 80 of the 88 Duttaphrynus samples considered (Duttaphrynus_ddRADseq_n88p80_131kb.fas). It was used to produce the tree presented in Supplementary Fig. 1.</li> <li>An alignment (fasta format) of 83,652 bp concatenating the RAD tags present in 25 unadmixed Duttaphrynus samples (Duttaphrynus_ddRADseq_n25p25_84kb.fas). It was used in the phylogenetic analyses presented in Fig. 1a and Supplementary Fig. 2.</li> <li>Two alignments (fasta format) of 482,648 bp and 628,293 bp concatenating the RAD tags present in 17 and 52 samples of D. melanostictus s. s. and D. cf. melanostictus, respectively (Duttaphrynus_melanostictus_ss_West_n17p17_483kb.fas and Duttaphrynus_cf_melanostictus_East_n52p52_628kb.fas). These were used in the network analyses presented in Fig. 2b.</li> <li>Three matrices of 851 SNPs, 3364 SNPs and 4782 SNPs, genotyped in 69, 17 and 52 samples of D. melanostictus s. l., D. melanostictus s. s. and D. cf. melanostictus, respectively (Duttaphrynus_melanostictus_sl_n69p69wrs_851SNPs.str, Duttaphrynus_melanostictus_ss_West_n17p17wrs_3364SNPs.str, Duttaphrynus_cf_melanostictus_East_n52p52wrs_4782SNPs.str). These were used in the Bayesian clustering and PCA analyses presented in Fig. 2a and Supplementary Figs. 3-4.</li> <li>An alignement (fasta format) of 383 sequences of the mitochondrial gene 16S (558 bp), including 382 sequences of Duttaphrynus + 1 outgroup (Duttaphrynus_16S.fas). It was used in the network analysis presented in Fig. 3b and the phylogenetic analysis presented in Supplementary Fig. 5.</li> <li>An alignement (fasta format) of 495 sequences of the mitochondrial gene ND3 (469 bp), including 494 sequences of Duttaphrynus + 1 outgroup (Duttaphrynus_ND3.fas). It was used in the network analysis presented in Fig. 3b and the phylogenetic analysis presented in Supplementary Fig. 6.</li> <li>An alignement (fasta format) of 27 full or partial mitogenomes (16,844 bp), including 26 sequences of Duttaphrynus + 1 outgroup (Duttaphrynus_mitogenomes.fas). It was used in the phylogenetic analyses presented in Fig. 1b and Supplementary Fig. 7.</li> </ul> The meta-data associated to these datasets are provided in the corresponding publication (Supplementary Data 1 and 4).

opencc-zeroDec 2015View details →

Data from: Foraging modality and plasticity in foraging traits determine the strength of competitive interactions among carnivorous plants, spiders, and toads

1. Foraging modalities (e.g., passive, sit-and-wait, active) and traits are plastic in some species, but the extent to which this plasticity affects interspecific competition remains unclear. 2. Using a long-term laboratory mesocosm experiment, we quantified competition strength and the plasticity of foraging traits in a guild of generalist predators of arthropods with a range of foraging modalities. 3. Each mesocosm contained eight passively foraging pink sundews, and we employed an experimental design where treatments were the presence or absence of a sit-and-wait foraging spider and actively foraging toad crossed with five levels of prey abundance. We hypothesized that actively foraging toads would outcompete the other species at low prey abundance, but that spiders and sundews would exhibit plasticity in foraging traits to compensate for strong competition when prey were limited. 4. Results generally supported our hypotheses. Toads had a greater effect on sundews at low prey abundances, and toad presence caused spiders to locate webs higher above the ground. Additionally, the closer large spider webs were to the ground, the greater the trichome densities produced by sundews. Also, spider webs were larger with than without toads and as sundew numbers increased, and these effects were more prominent as resources became limited. Finally, spiders negatively affected toad growth only at low prey abundance. 5. These findings highlight the long-term importance of foraging modality and plasticity of foraging traits in determining the strength of competition within and across taxonomic kingdoms. Future research should assess whether plasticity in foraging traits helps to maintain coexistence within this guild and whether foraging modality can be used as a trait to reliably predict the strength of competitive interactions.

opencc-zeroDec 2016View details →

Data from: Locomotor performance of cane toads differs between native-range and invasive populations

Invasive species provide a robust opportunity to evaluate how animals deal with novel environmental challenges. Shifts in locomotor performance—and thus the ability to disperse—(and especially, the degree to which it is constrained by thermal and hydric extremes) are of special importance, because they might affect the rate that an invader can spread. We studied cane toads (Rhinella marina) across a broad geographical range: two populations within the species' native range in Brazil, two invasive populations on the island of Hawai'i and eight invasive populations encompassing the eastern, western and southern limits of the toad invasion in Australia. A toad's locomotor performance on a circular raceway was strongly affected by both its temperature and its hydration state, but the nature and magnitude of those constraints differed across populations. In their native range, cane toads exhibited relatively low performance (even under optimal test conditions) and a rapid decrease in performance at lower temperatures and hydration levels. At the other extreme, performance was high in toads from southern Australia, and virtually unaffected by desiccation. Hawai'ian toads broadly resembled their Brazilian conspecifics, plausibly reflecting similar climatic conditions. The invasion of Australia has been accompanied by a dramatic enhancement in the toads' locomotor abilities, and (in some populations) by an ability to maintain locomotor performance even when the animal is cold and/or dehydrated. The geographical divergences in performance among cane toad populations graphically attest to the adaptability of invasive species in the face of novel abiotic challenges.

opencc-zeroDec 2016View details →

Data from: The costs of parasite infection: effects of removing lungworms on performance, growth and survival of free-ranging cane toads

1.Most research on the effects of parasites on their hosts has focused on the parasites of mammals or birds (especially, domesticated taxa) rather than systems in which the hosts are ectothermic wildlife species. 2.We used experimental methods (antihelminthic drugs) to quantify the effects of lungworms (Rhabdias pseudosphaerocephala) on their anuran hosts, the invasive cane toad (Rhinella marina). 3.In captivity, eradicating lungworms enhanced toad activity (measures of boldness and level of spontaneous activity), performance (locomotor speed, climbing ability), and foraging success (feeding rate). 4.In free-ranging toads (n = 123) at a site in tropical Australia, eradicating lungworm infection increased rates of host survival by 8%, movement by 20%, growth by 28% and elaboration of male secondary sexual characteristics by 30%. The presence of the lungworm thus has a substantial negative effect on fitness-related traits of the host. 5.Given their long shared evolutionary history and the mild inflammatory and immune response elicited by the parasite in the host, the magnitude of the effects of parasite removal were surprising. Parasites may impose hidden costs, related to modification of host behaviour or metabolism. Experimental removal of parasites can be a useful means of quantifying costs of infection.

opencc-zeroDec 2018View details →

Data from: Testing an hypothesis of hybrid zone movement for toads in France

Hybrid zone movement may result in substantial unidirectional introgression of selectively neutral material from the local to the advancing species, leaving a genetic footprint. This genetic footprint is represented by a trail of asymmetric tails and displaced cline centres in the wake of the moving hybrid zone. A peak of admixture linkage disequilibrium is predicted to exist ahead of the centre of the moving hybrid zone. We test these predictions of the movement hypothesis in a hybrid zone between common (Bufo bufo) and spined toads (B. spinosus), using 31 nuclear and one mtDNA SNPs along a transect in the northwest of France. Average effective selection in Bufo hybrids is low and clines vary in shape and centre. A weak pattern of asymmetric introgression is inferred from cline discordance of seven nuclear markers. The dominant direction of gene flow is from B. spinosus to B. bufo and is in support of southward movement of the hybrid zone. Conversely, a peak of admixture linkage disequilibrium north of the hybrid zone suggests northward movement. These contrasting results can be explained by reproductive isolation of the B. spinosus and B. bufo gene pools at the southern (B. spinosus) side of the hybrid zone. The joint occurrence of asymmetric introgression and admixture linkage disequilibrium can also be explained by the combination of low dispersal and random genetic drift due to low effective population sizes.

opencc-zeroJul 2021View details →

Rates of expansion of invasive cane toads in New South Wales

Geographical variation in abiotic and biotic conditions can significantly affect the rate that an invasive species expands its range. The colonisation of Australia by cane toads (Rhinella marina) has attracted extensive research, but mostly in tropical regions rather than cooler climatic zones. We assembled multiple datasets to characterise the historical spread of toads at their southern (cool-climate) invasion front in north-eastern New South Wales (NSW). Perhaps because toads are relatively easy to find, visual and acoustic surveys appear to be as effective as eDNA-based surveys in detecting the species' presence. Expansion of the toads' range in NSW has occurred through the establishment of satellite populations as well as by growth of the range-core. Overall rates of spread have been more than tenfold lower than on the tropical front (means of <5 km vs. >50 km per year), and in some decades, the toads' southern range has declined rather than expanded. Overall rates of spread since 1970 have accelerated to the south (through coastal habitats), but not to the west (into montane areas). The toads' range has expanded most rapidly in decades with dry, warm weather conditions, but predicted future changes to climate are likely to have only minor effects on rates of toad spread. Understanding historical patterns of toad invasion in NSW can clarify probable future spread, and hence identify priority areas for control programs.

opencc-zeroJul 2021View details →

Data from: Field trials of chemical suppression of embryonic cane toads (Rhinella marina) by older conspecifics

1. Laboratory experiments have shown that the viability of embryos of the invasive cane toad (Rhinella marina) can be reduced by exposure to chemical cues from older conspecific larvae. These effects (very strong in laboratory trials) may offer an exciting new approach to controlling this problematic invasive species in Australia. However, the degree to which the method works in natural environments has yet to be assessed. 2. Our experiments in the laboratory and in semi-natural outdoor waterbodies show that chemical cues from tadpoles do indeed suppress the growth, development and survival of conspecific larvae that are exposed as embryos and do so in a dose-dependent manner; higher tadpole densities cause greater suppression of embryos. 3. In semi-natural outdoor waterbodies, suppressor-exposed tadpoles were less than half as likely to survive to metamorphosis as were controls, and were much smaller when they did so and hence, less likely to survive the metamorph stage. Additionally, female cane toads were less likely to oviposit in a waterbody containing free-ranging (but not cage-enclosed) tadpoles, suggesting that the presence of tadpoles (rather than the chemical cues they produce) may discourage oviposition. 4. Broadly, our results suggest that the suppression effect documented in laboratory studies does indeed occur in the field also, and hence that we may be able to translate that approach to develop new and more effective ways to reduce rates of recruitment of peri-urban populations of cane toads in their invasive range.

opencc-zeroJul 2021View details →

Data from: Identification of candidate loci for adaptive phenotypic plasticity in natural populations of spadefoot toads

Phenotypic plasticity allows organisms to alter their phenotype in direct response to changes in the environment. Despite growing recognition of plasticity's role in ecology and evolution, few studies have probed plasticity's molecular bases—especially using natural populations. We investigated the genetic basis of phenotypic plasticity in natural populations of spadefoot toads (Spea multiplicata). Spea tadpoles normally develop into an 'omnivore' morph that is favored in long-lasting, low-density ponds. However, if tadpoles consume freshwater shrimp or other tadpoles, they can alternatively develop (via plasticity) into a 'carnivore' morph that is favored in shallow, high-density ponds. By combining natural variation in pond ecology and morph production with population genetic approaches, we identified candidate loci associated with morph (carnivores versus omnivores) and loci associated with adaptive phenotypic plasticity (adaptive versus maladaptive morph choice). Our candidate morph loci mapped to two genes, whereas our candidate plasticity loci mapped to 14 genes. In both cases, the identified genes tended to have functions related to their putative role in spadefoot tadpole biology. Our results thereby form the basis for future studies into the molecular mechanisms that mediate plasticity in spadefoots. More generally, these results illustrate how diverse loci might be deployed to mediate adaptive plasticity.Phenotypic plasticity allows organisms to alter their phenotype in direct response to changes in the environment. Despite growing recognition of plasticity's role in ecology and evolution, few studies have probed plasticity's molecular bases—especially using natural populations. We investigated the genetic basis of phenotypic plasticity in natural populations of spadefoot toads (Spea multiplicata). Spea tadpoles normally develop into an 'omnivore' morph that is favored in long-lasting, low-density ponds. However, if tadpoles consume freshwater shrimp or other tadpoles, they can alternatively develop (via plasticity) into a 'carnivore' morph that is favored in shallow, high-density ponds. By combining natural variation in pond ecology and morph production with population genetic approaches, we identified candidate loci associated with morph (carnivores versus omnivores) and loci associated with adaptive phenotypic plasticity (adaptive versus maladaptive morph choice). Our candidate morph loci mapped to two genes, whereas our candidate plasticity loci mapped to 14 genes. In both cases, the identified genes tended to have functions related to their putative role in spadefoot tadpole biology. Our results thereby form the basis for future studies into the molecular mechanisms that mediate plasticity in spadefoots. More generally, these results illustrate how diverse loci might be deployed to mediate adaptive plasticity.