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Hossack BR, Oja EB, Owens AK, Hall D, Cobos C, Crawford CL, Goldberg CS, Hedwall S, Howell PE, Lemos-Espinal JA, MacVean SK, McCaffery M, Mosley C, Muths E, Sigafus BH, Sredl MJ, Rorabaugh JC. Empirical evidence for effects of invasive American Bullfrogs on occurrence of native amphibians and emerging pathogens. Ecol Appl 2023; 33:e2785. [PMID: 36478292 DOI: 10.1002/eap.2785] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 09/15/2022] [Accepted: 10/04/2022] [Indexed: 06/17/2023]
Abstract
Invasive species and emerging infectious diseases are two of the greatest threats to biodiversity. American Bullfrogs (Rana [Lithobates] catesbeiana), which have been introduced to many parts of the world, are often linked with declines in native amphibians via predation and the spread of emerging pathogens such as amphibian chytrid fungus (Batrachochytrium dendrobatidis [Bd]) and ranaviruses. Although many studies have investigated the potential role of bullfrogs in the decline of native amphibians, analyses that account for shared habitat affinities and imperfect detection have found limited support for clear effects. Similarly, the role of bullfrogs in shaping the patch-level distribution of pathogens is unclear. We used eDNA methods to sample 233 sites in the southwestern USA and Sonora, Mexico (2016-2018) to estimate how the presence of bullfrogs affects the occurrence of four native amphibians, Bd, and ranaviruses. Based on two-species, dominant-subordinate occupancy models fitted in a Bayesian context, federally threatened Chiricahua Leopard Frogs (Rana chiricahuensis) and Western Tiger Salamanders (Ambystoma mavortium) were eight times (32% vs. 4%) and two times (36% vs. 18%), respectively, less likely to occur at sites where bullfrogs occurred. Evidence for the negative effects of bullfrogs on Lowland Leopard Frogs (Rana yavapaiensis) and Northern Leopard Frogs (Rana pipiens) was less clear, possibly because of smaller numbers of sites where these native species still occurred and because bullfrogs often occur at lower densities in streams, the primary habitat for Lowland Leopard Frogs. At the community level, Bd was most likely to occur where bullfrogs co-occurred with native amphibians, which could increase the risk to native species. Ranaviruses were estimated to occur at 33% of bullfrog-only sites, 10% of sites where bullfrogs and native amphibians co-occurred, and only 3% of sites where only native amphibians occurred. Of the 85 sites where we did not detect any of the five target amphibian species, we also did not detect Bd or ranaviruses; this suggests other hosts do not drive the distribution of these pathogens in our study area. Our results provide landscape-scale evidence that bullfrogs reduce the occurrence of native amphibians and increase the occurrence of pathogens, information that can clarify risks and aid the prioritization of conservation actions.
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Affiliation(s)
- Blake R Hossack
- U.S. Geological Survey, Northern Rocky Mountain Science Center, Wildlife Biology Program, W. A. Franke College of Forestry & Conservation, University of Montana, Missoula, Montana, USA
| | - Emily B Oja
- Wildlife Biology Program, W. A. Franke College of Forestry & Conservation, University of Montana, Missoula, Montana, USA
| | | | - David Hall
- School of Natural Resources and the Environment, University of Arizona, Tucson, Arizona, USA
| | - Cassidi Cobos
- Turner Endangered Species Fund, Ladder Ranch, Caballo, New Mexico, USA
| | | | | | | | - Paige E Howell
- U.S. Fish and Wildlife Service, Hadley, Massachusetts, USA
| | | | | | | | - Cody Mosley
- Arizona Game and Fish Department, Phoenix, Arizona, USA
| | - Erin Muths
- U.S. Geological Survey, Fort Collins Science Center, Fort Collins, Colorado, USA
| | - Brent H Sigafus
- U.S. Geological Survey, Southwest Biological Science Center, Tucson, Arizona, USA
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Olivier-Espejel S, Hurley BP, Garnas J. Assessment of beetle diversity, community composition and potential threats to forestry using kairomone-baited traps. Bull Entomol Res 2017; 107:106-117. [PMID: 27545502 DOI: 10.1017/s0007485316000699] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Traps designed to capture insects during normal movement/dispersal, or via attraction to non-specific (plant) volatile lures, yield by-catch that carries valuable information about patterns of community diversity and composition. In order to identify potential native/introduced pests and detect predictors of colonization of non-native pines, we examined beetle assemblages captured in intercept panel traps baited with kairomone lures used during a national monitoring of the woodwasp, Sirex noctilio, in Southern Africa. We identified 50 families and 436 morphospecies of beetles from nine sites sampled in both 2008 and 2009 and six areas in 2007 (trap catch pooled by region) across a latitudinal and elevational gradient. The most diverse groups were mainly those strongly associated with trees, known to include damaging pests. While native species dominated the samples in terms of richness, the dominant species was the introduced bark beetle Orthotomicus erosus (Curculionidae: Scolytinae) (22 ± 34 individuals/site). Four Scolytinae species without previous records in South Africa, namely Coccotrypes niger, Hypocryphalus robustus (formerly Hypocryphalus mangiferae), Hypothenemus birmanus and Xyleborus perforans, were captured in low abundances. Communities showed temporal stability within sites and strong biogeographic patterns across the landscape. The strongest single predictors of community composition were potential evaporation, latitude and maximum relative humidity, while the strongest multifactor model contained elevation, potential evaporation and maximum relative humidity. Temperature, land use variables and distance to natural areas did not significantly correlate with community composition. Non-phytophagous beetles were also captured and were highly diverse (32 families) perhaps representing important beneficial insects.
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Affiliation(s)
- S Olivier-Espejel
- Department of Zoology and Entomology,Forestry and Agricultural Biotechnology Institute (FABI),University of Pretoria,0002,South Africa
| | - B P Hurley
- Department of Zoology and Entomology,Forestry and Agricultural Biotechnology Institute (FABI),University of Pretoria,0002,South Africa
| | - J Garnas
- Department of Zoology and Entomology,Forestry and Agricultural Biotechnology Institute (FABI),University of Pretoria,0002,South Africa
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Benkwitt CE. Predator effects on reef fish settlement depend on predator origin and recruit density. Ecology 2017; 98:896-902. [PMID: 28072444 DOI: 10.1002/ecy.1732] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 12/12/2016] [Accepted: 12/21/2016] [Indexed: 11/09/2022]
Abstract
During major life-history transitions, animals often experience high mortality rates due to predation, making predator avoidance particularly advantageous during these times. There is mixed evidence from a limited number of studies, however, regarding how predator presence influences settlement of coral-reef fishes and it is unknown how other potentially mediating factors, including predator origin (native vs. nonnative) or interactions among conspecific recruits, mediate the non-consumptive effects of predators on reef fish settlement. During a field experiment in the Caribbean, approximately 52% fewer mahogany snapper (Lutjanus mahogoni) recruited to reefs with a native predator (graysby grouper, Cephalopholis cruentata) than to predator-free control reefs and reefs with an invasive predator (red lionfish, Pterois volitans) regardless of predator diet. These results suggest that snapper recruits do not recognize nonnative lionfish as a threat. However, these effects depended on the density of conspecific recruits, with evidence that competition may limit the response of snapper to even native predators at the highest recruit densities. In contrast, there was no effect of predator presence or conspecific density on the recruitment of bicolor damselfish (Stegastes partitus). These context-dependent responses of coral-reef fishes to predators during settlement may influence individual survival and shape subsequent population and community dynamics.
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Affiliation(s)
- Cassandra E Benkwitt
- Department of Integrative Biology, Oregon State University, Corvallis, Oregon, 97331, USA
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Bufford JL, Hulme PE, Sikes BA, Cooper JA, Johnston PR, Duncan RP. Taxonomic similarity, more than contact opportunity, explains novel plant-pathogen associations between native and alien taxa. New Phytol 2016; 212:657-667. [PMID: 27440585 DOI: 10.1111/nph.14077] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 05/25/2016] [Indexed: 06/06/2023]
Abstract
Novel associations between plants and pathogens can have serious impacts on managed and natural ecosystems world-wide. The introduction of alien plants increases the potential for biogeographically novel plant-pathogen associations to arise when pathogens are transmitted from native to alien plant species and vice versa. We quantified biogeographically novel associations recorded in New Zealand over the last 150 yr between plant pathogens (fungi, oomycetes and plasmodiophorids) and vascular plants. We examined the extent to which taxonomic similarity, pathogen traits, contact opportunity and sampling effort could explain the number of novel associates for host and pathogen species. Novel associations were common; approximately one-third of surveyed plants and pathogens were recorded with at least one biogeographically novel associate. Native plants had more alien pathogens than vice versa. Taxonomic similarity between the native and alien flora and the total number of recorded associations (a measure of sampling effort) best explained the number of novel associates among species. The frequency of novel associations and the importance of sampling effort as an explanatory variable emphasize the need for effective monitoring and risk assessment tools to mitigate the potential environmental and economic impact of novel pathogen associations.
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Affiliation(s)
- Jennifer L Bufford
- Bio-Protection Research Centre, Lincoln University, PO Box 85084, Lincoln, 7647, New Zealand.
| | - Philip E Hulme
- Bio-Protection Research Centre, Lincoln University, PO Box 85084, Lincoln, 7647, New Zealand
| | - Benjamin A Sikes
- Department of Ecology and Evolutionary Biology and Kansas Biological Survey, University of Kansas, 2101 Constant Ave, Lawrence, KS, 66047, USA
| | - Jerry A Cooper
- Landcare Research, PO Box 69040, Lincoln, 7640, New Zealand
| | - Peter R Johnston
- Landcare Research, Private Bag 92170, Auckland, 1142, New Zealand
| | - Richard P Duncan
- Bio-Protection Research Centre, Lincoln University, PO Box 85084, Lincoln, 7647, New Zealand
- Institute for Applied Ecology, University of Canberra, Canberra, ACT, 2601, Australia
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Abstract
PURPOSE In this article, the authors examine (a) the effect of semantic context on accentedness, comprehensibility, and intelligibility of Spanish-accented American English (AE) as judged by monolingual AE listeners and (b) the interaction of semantic context and accentedness on comprehensibility and intelligibility. METHOD Twenty adult native (L1) Spanish speakers proficient in AE and 4 L1 AE speakers (controls) read 48 statements consisting of true-false, semantically meaningful, and semantically anomalous sentences. Eighty monolingual AE listeners assessed accentedness, comprehensibility, and intelligibility of the statements. RESULTS A significant main effect was found for semantic category on all 3 dependent variables. Accents were perceived to be stronger, and both comprehensibility and intelligibility were worse, in semantically anomalous contexts. Speaker data were grouped into strong, mid-level, and mild accents. The interaction between semantic category and accent was significant for both comprehensibility and intelligibility. The effect of semantic context was strongest for strong accents. Intelligibility was excellent for speakers with mid-level accents in true-false and semantically meaningful contexts, and it was excellent for mild accents in all contexts. CONCLUSIONS Listeners access semantic information, in addition to phonetic and phonotactic features, in the perception of nonnative speech. Both accent level and semantic context are important in research on foreign-accented speech.
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Storz SR, Tschinkel WR. Distribution, spread, and ecological associations of the introduced ant Pheidole obscurithorax in the southeastern United States. J Insect Sci 2004; 4:12. [PMID: 15861228 PMCID: PMC528872 DOI: 10.1093/jis/4.1.12] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/20/2003] [Accepted: 03/21/2004] [Indexed: 05/24/2023]
Abstract
A field survey of the southeastern United States showed that Pheidole obscurithorax Naves, an ant introduced from South America, inhabits a 80-km-wide band along the coast between Mobile, Alabama, and Tallahassee, Florida, and is continuing to increase its range. In Tallahassee P. obscurithorax is rapidly spreading, and its nest density increased by a factor of 6.4 over a two-year period. Evidence suggests that P. obscurithorax has spread gradually by natural means. It coexists with the fire ant Solenopsis invicta Buren, appears to be part of a largely exotic community of ants that are tolerant of highly disturbed habitats, and seems to have little negative effect on the ant communities that it invades.
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Affiliation(s)
- Shonna R Storz
- Department of Biological Science, Florida State University, Tallahassee, FL 32306-1100, USA.
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