What factors affect the density of cane toads (Rhinella marina) in the Solomon Islands?

2015 ◽  
Vol 21 (3) ◽  
pp. 200 ◽  
Author(s):  
Patrick Pikacha ◽  
Tyrone Lavery ◽  
Luke K.-P. Leung
Keyword(s):  
Solomon Islands ◽  
Distance Sampling ◽  
Information Criterion ◽  
Forest Types ◽  
Coastal Forests ◽  
Cane Toad ◽  
Breeding Sites ◽  
Rhinella Marina ◽  
Disturbed Areas ◽  
Parsimonious Model

Cane toads (Rhinella marina) were introduced to the Solomon Islands in the 1940s, and quickly spread across the archipelago. Between May 2009 and August 2012, cane toads were recorded on 11 of 13 islands surveyed, and the densities of toads were estimated by distance sampling on seven of these islands. Modified Akaike’s Information Criterion (AICc) tests were used to find the most parsimonious model for cane toad density in the Solomon Islands. The results showed that mean toad density was higher on Gatokae and Guadalcanal than on Bougainville, Choiseul, Kolombangara and Rendova. A plausible explanation for this is that Guadalcanal had an abundance of breeding sites, and that Gatokae may have been recently colonised with a typical sharp rise in toad densities. The model also showed that mean toad density was higher in coastal forests than in other forest types (e.g lowland, hill and montane forests). Coastal forests have higher disturbance levels as a result of villages and towns. Disturbance was associated with increased toad densities in the model. These findings suggest that cane toad management efforts should target coastal forests and disturbed areas along roads and tracks leading to important biodiversity reserves.

Factors affecting frog density in the Solomon Islands

2016 ◽  
Vol 22 (3) ◽  
pp. 223 ◽  
Author(s):  
Patrick Pikacha ◽  
Chris Filardi ◽  
Clare Morrison ◽  
Luke Leung
Keyword(s):  
Forest Type ◽  
Solomon Islands ◽  
Distance Sampling ◽  
Information Criterion ◽  
Forest Types ◽  
Lowland Forest ◽  
Factors Affecting ◽  
High Conservation ◽  
Parsimonious Model ◽  
Species Being

This paper identifies some important factors affecting the density of frogs in the Solomon Islands. Distance sampling was used to estimate frog density in all major frog habitats across 13 islands. A total of 109 transects, covering five forest types (coastal, freshwater marshes, lowland forest, hill or ridge, and montane forest) were used, with 16 species being sampled. Estimated densities ranged from 2 ha–1 to 675 ha–1. Akaike’s Information Criterion (AIC) was used to select the most parsimonious model of frog density. Factors identified in the selected model to predict density of Batrachylodes elegans, Batrachylodes vertebralis, Ceratobatrachus guentheri, Discodeles bufoniformis, Discodeles guppyi, Discodeles malukuna, Litoria thesaurensis, Palmatorappia solomonis, Platymantis guppyi, Platymantis neckeri, Platymantis solomonis, Platymantis sp., Platymantis weberi, and Rana kreffti were island, landform, and forest type. Additional factors such as disturbance, leaf litter, shrub, and understorey were also described by the regression model as predictors of density for B. vertebralis, C. guentheri, D. guppyi, D. malukuna, Pal. solomonis, P. guppyi, and R. kreffti. These findings have important management implications for the conservation of frogs in the Solomon Islands. High densities of most species were strongly related with forest type and low disturbance. Preservation of rainforest, in especially high conservation value old-growth forests, is imperative to protecting these species.

Description of a new species from the genus Eugoa Walker, 1858 (Lepidoptera: Erebidae: Arctiinae) from the Solomon Islands

Zootaxa ◽  
2018 ◽  
Vol 4504 (1) ◽  
pp. 135
Author(s):  
KAROL BUCSEK ◽  
MICHAL RINDOŠ
Keyword(s):  
Solomon Islands ◽  
Habitat Preferences ◽  
Forest Types ◽  
Coastal Forests ◽  
Additional Species ◽  
Life History Data ◽  
Western Palearctic ◽  
Wide Range ◽  
The 19Th Century ◽  
A New Species

The genus Eugoa Walker, 1858 belongs to the tribe Lithosiini and occurs across the Old World, excluding the Western Palearctic Region. Currently, it contains around 120 species, most of them distributed across Asia (Bucsek 2016a, b; Dubatolov & Bucsek 2016; Schaus 1922). Ten additional species have been described from Australasia (Bethune-Baker 1904; Rothschild 1915). Since the 19th century, several authors have addressed the taxonomy of the genus Eugoa (Buscek 2008, 2012, 2016a, b; Černý & Bucsek 2014; Hampson 1891, 1898, 1900; Rothschild 1915; Seitz 1914; Van Eecke 1930), but only a few described their habitat preferences (e.g. Holloway 2001). These small to medium sized moths with brown, or brown—cream coloured forewings inhabit a wide range of forest types (e.g. alluvial, dipterocarp, heath, kerangas, etc.) from mangroves and lowland-coastal forests (about 300m asl) up to upper montane forests (about 1500 m asl). Unfortunately, life history data for species in the genus Eugoa still remain unavailable. 

Cane toad ( Rhinella marina ) vitamin A, vitamin E, and carotenoid kinetics

Zoo Biology ◽  
2021 ◽  
Author(s):  
Tarra Freel ◽  
Elizabeth Koutsos ◽  
Larry J. Minter ◽  
Troy Tollefson ◽  
Frank Ridgley ◽  
...  
Keyword(s):  
Vitamin E ◽  
Vitamin A ◽  
Cane Toad ◽  
Rhinella Marina

scholarly journals HEIGHT-DIAMETER MODELS FOR THREE SUBTROPICAL FOREST TYPES IN SOUTHERN BRAZIL

2015 ◽  
Vol 39 (3) ◽  
pp. 205-215 ◽  
Author(s):  
Alexander Christian Vibrans ◽  
Paolo Moser ◽  
Laio Zimermann Oliveira ◽  
João Paulo de Maçaneiro
Keyword(s):  
Deciduous Forest ◽  
Tree Height ◽  
Information Criterion ◽  
Confidence Bands ◽  
Natural Forests ◽  
Forest Types ◽  
Model Quality ◽  
Statistical Parameters ◽  
Santa Catarina ◽  
Ombrophilous Forest

Total tree height (h) is often difficult to measure in natural forests. Regression models based on easily accessed variables like DBH (d) can be an alternative, since their assumptions are validated. The aims of this study are to: (i) calibrate specific and generic h-d models for three forest types (Seasonal Deciduous Forest, DEC; Mixed Ombrophilous Forest, MIX; and Dense Rainforest, DEN) in Santa Catarina state testing the regression assumptions and evaluating model quality; (ii) verify different h-d relationship between forest types. The dataset (1,766 measured tree h and 3,150 estimated h) was collected by Santa Catarina Forest and Floristic Inventory (IFFSC) in 418 systematically located sample plots. Models were calibrated for two datasets, one containing hypsometer measurements, the other h estimations made by field crews. Specific models were calibrated for species with at least 30 sampled trees. Residual normality, randomness and heteroskedasticity were evaluated by analytical methods. Confidence bands were generated by the Working-Hotelling method; z test for means was applied to compare models based on the two databases. The statistical parameters such as corrected Akaike Information Criterion provided evidences that logarithmic models were better adjusted to the data. Both datasets were statistically different for DEN and MIX. Differences in h-d relationships were found between forest types. The use of calibrated h-d models is an alternative for studying the relationships between these variables and to assess vertical structure patterns of forest communities, when h measurements are not feasible, although, for situations that more accurate h values are needed, they will not always provide reliable predictions.

Changes in urinary testosterone and corticosterone metabolites during short-term confinement with repeated handling in wild male cane toads (Rhinella marina)

2011 ◽  
Vol 59 (4) ◽  
pp. 264 ◽  
Author(s):  
Edward J. Narayan ◽  
Frank C. Molinia ◽  
John F. Cockrem ◽  
Jean-Marc Hero
Keyword(s):  
Adult Male ◽  
Reproductive Effort ◽  
Hormone Secretion ◽  
Reproductive Hormone ◽  
Cane Toad ◽  
Short Term ◽  
Rhinella Marina ◽  
Testosterone Secretion ◽  
Metabolite Concentrations ◽  
Corticosterone Metabolites

Stressors generally decrease testosterone secretion and inhibit reproduction in animals. Urinary testosterone and corticosterone metabolite concentrations were measured in adult male cane toads (Rhinella marina) at the time of capture from the wild and during 24 h of confinement with repeated handling. Mean urinary testosterone concentrations increased 2 h after capture, were significantly elevated above initial concentrations at 5 h, and then declined. Mean testosterone concentrations remained elevated 24 h after capture. Mean urinary corticosterone concentrations increased after capture, were significantly elevated above initial concentrations at 2 h, and remained elevated thereafter. This is the first report in amphibians of an increase in testosterone excretion after capture from the wild, with previous studies showing either no change or decline in testosterone. This finding may be associated with the mating strategy and maintenance of reproductive effort in the cane toad, a species that shows explosive breeding and agonistic male–male interactions during breeding. The finding that testosterone excretion increases rather than decreases after capture in male cane toads shows that it should not be generally assumed that reproductive hormone secretion will decrease after capture in amphibians.

scholarly journals Non-reproductive male cane toads ( Rhinella marina ) withhold sex-identifying information from their rivals

2019 ◽  
Vol 15 (8) ◽  
pp. 20190462 ◽  
Author(s):  
Crystal Kelehear ◽  
Richard Shine
Keyword(s):  
Sexual Identity ◽  
Standardized Tests ◽  
Opportunity Cost ◽  
Cane Toad ◽  
Rhinella Marina ◽  
Secondary Sexual Characteristics ◽  
Sexual Characteristics ◽  
Reproductive Male ◽  
Male Specific ◽  
Do So

A male cane toad ( Rhinella marina ) that mistakenly clasps another male (rather than a female) in a sexual embrace (amplexus) can be induced to dismount by a male-specific ‘release call'. Although that sex-identifying system can benefit both males in that interaction, our standardized tests showed that one-third of male cane toads did not emit release calls when grasped. Most of those silent males were small, had small testes relative to body mass, and had poorly developed secondary sexual characteristics. If emitting a release call is costly (e.g. by attracting predators), a non-reproductive male may benefit by remaining silent; other cues (such as skin rugosity) will soon induce the amplexing male to dismount, and the ‘opportunity cost’ to being amplexed (inability to search for and clasp a female) is minimal for non-reproductive males. Hence, male toads may inform other males about their sexual identity only when it is beneficial to do so.

Transposable elements expression in Rhinella marina (cane toad) specimens submitted to immune and stress challenge

Genetica ◽  
2021 ◽  
Author(s):  
Adriana Ludwig ◽  
Michelle Orane Schemberger ◽  
Camilla Borges Gazolla ◽  
Joana de Moura Gama ◽  
Iraine Duarte ◽  
...  
Keyword(s):  
Transposable Elements ◽  
Cane Toad ◽  
Rhinella Marina

scholarly journals Prerecruit survival and recruitment of northern Gulf of St Lawrence Atlantic cod

2008 ◽  
Vol 65 (6) ◽  
pp. 946-952 ◽  
Author(s):  
Daniel E. Duplisea ◽  
Dominique Robert
Keyword(s):  
Linear Models ◽  
Atlantic Cod ◽  
Information Criterion ◽  
Factors Affecting ◽  
Control Rules ◽  
Strategy Evaluation ◽  
Stock Biomass ◽  
Spawning Stock ◽  
Long Time ◽  
Parsimonious Model

Abstract Duplisea, D. E., and Robert, D. 2008. Prerecruit survival and recruitment of northern Gulf of St Lawrence Atlantic cod. – ICES Journal of Marine Science, 65: 946–952. Recruitment (R) of exploited marine fish populations is usually modelled exclusively as a function of spawning-stock biomass (SSB). A problem arising when modelling over long time-series is that the nature of the R–SSB relationship is unlikely to be stationary. Changes are often interpreted as productivity regime shifts and are linked to alterations in prerecruit survival rate. We examine the role of environment and predation by fish and harp seals as factors affecting the R–SSB relationship in the northern Gulf of St Lawrence cod, by fitting linear models using combinations of covariates to explain cod prerecruit survival. The most parsimonious model (based on a Bayesian Information Criterion, BIC) included cod, mackerel, and temperature, whereas redfish and seals did not appear in any of the best-fit models. Recruitment models derived from this analysis could be used in operating models for management strategy evaluation simulations for northern Gulf cod, so one could develop harvest control rules that are robust to changes in recruitment productivity regimes.

scholarly journals Draft genome assembly of the invasive cane toad, Rhinella marina

GigaScience ◽  
2018 ◽  
Vol 7 (9) ◽  
Author(s):  
Richard J Edwards ◽  
Daniel Enosi Tuipulotu ◽  
Timothy G Amos ◽  
Denis O'Meally ◽  
Mark F Richardson ◽  
...  
Keyword(s):  
Genome Assembly ◽  
Draft Genome ◽  
Cane Toad ◽  
Rhinella Marina ◽  
Draft Genome Assembly
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