Bufo Bankorensis Research Articles

The ecological waterfront design for Bufo bankorensis by using artificial neural network methods

Over the last three decades, the threat to amphibian animals has become more and more serious. Especially, the loss of natural habitats caused by changes to the way land is used by human beings. This issue has hit amphibians extraordinarily hard. Moreover, it is known that amphibians are particularly vulnerable to human activities because they rely on both terrestrial and aquatic habitats for survival. Due to increased development in many areas, concrete structures are often built along water bodies in order to increase the safety of structures. The development of solid banks along streams related with human improvement has become a major issue in Taiwan. Most ecosystems used by amphibians are lakes, ponds, rivers and stream banks. However, there is no related design solution to accommodate the needs of those amphibians. The need to develop the relevant design specification considering protecting the amphibian is very urgent. The objectives of this study were to investigate (1) the relationships between the physical characteristics and climbing ability of toads, (2) whether statistics analysis can be can be utilized to improve the understandings of the actual attributes of amphibian, (3) whether Artificial Neural Network can be used to simulate the climbing ability of toad. The experimental and numerical results showed that there is a strong positive correlation between physical characteristics and climbing ability of toads.

Trophic roles of Bufo bankorensis (Barbour 1908) tadpoles in an Asian subtropical stream

ABSTRACTTadpoles may be omnivorous with diverse trophic positions beyond herbivory, and may require multiple approaches for identification. Understanding the trophic and ecological roles of omnivorous tadpoles may require examination at a species level. The goals of this study were to determine the trophic positions of Bufo bankorensis tadpoles by using stable isotopes and food selection experiments, verify the tadpoles’ effects on benthic resources with enclosure–exclosure experiments, and examine their role on nutrient cycling. Stable isotope experiments showed that B. bankorensis tadpoles fed on algae and animal items, indicating a trophic level close to that of a damselfly. The food selection experiments showed that the tadpoles fed on dead tadpoles and mayflies but not on live animals, making them necrophagous, and further testing revealed that the tadpoles preferred dead tadpoles over algae. In the enclosure–exclosure experiment, the tadpoles reduced the amounts of algae and organic matter and changed the compositions of algal growth forms. The tadpoles released nitrogen (N) into the ambient water, which was then recycled by benthic algae, as revealed by an 15N addition experiment. We concluded that B. bankorensis tadpoles have trophic and ecological roles related to their trophic positions in a subtropical stream ecosystem.

Thermal Plasticity in the Burst Swimming of Bufo bankorensis Larvae

Thermal Plasticity in the Burst Swimming of Bufo bankorensis Larvae

Using the climbing ability of Bufo bankorensis and Hynobius arisanensis to discuss the amphibious corridor design for high altitude areas

In recent years, as Taiwan’s environmental development density continuously increases, the adverse effect on ecology grows increasingly, especially the effect of mountain waterfront artificial facilities on amphibians. This study measures the body weight and body length of Bufo bankorensis and Hynobius arisanensis, and uses different climatic conditions of side slope matrix, angle, ambient temperature, and humidity to research the differences in climbing ability, and attempts to determine the optimum design model of an amphibious corridor. The findings show that the average weight and body length of Bufo bankorensis are greater than Hynobius arisanensis, where the body weight difference is 33 times and the body length difference is 3.29cm. Hynobius arisanensis has better climbing ability per unit body weight than Bufo bankorensis. Hynobius arisanensis has the best climbing ability on a grass matrix. Generally speaking, the optimum environments for Bufo bankorensis are Clay>Grass>Concrete>Wood>Cobblestone; while the optimum environments for Hynobius arisanensis are Grass>Clay>Cobblestone>Wood>Concrete. This study is expected to provide useful reference for future high mountain area waterfront designers.

A new phylogeographic pattern of endemic Bufo bankorensis in Taiwan Island is attributed to the genetic variation of populations.

AimTo comprehend the phylogeographic patterns of genetic variation in anurans at Taiwan Island, this study attempted to examine (1) the existence of various geological barriers (Central Mountain Ranges, CMRs); and (2) the genetic variation of Bufo bankorensis using mtDNA sequences among populations located in different regions of Taiwan, characterized by different climates and existing under extreme conditions when compared available sequences of related species B. gargarizans of mainland China.Methodology/Principal FindingsPhylogenetic analyses of the dataset with mitochondrial DNA (mtDNA) D-loop gene (348 bp) recovered a close relationship between B. bankorensis and B. gargarizans, identified three distinct lineages. Furthermore, the network of mtDNA D-loop gene (564 bp) amplified (279 individuals, 27 localities) from Taiwan Island indicated three divergent clades within B. bankorensis (Clade W, E and S), corresponding to the geography, thereby verifying the importance of the CMRs and Kaoping River drainage as major biogeographic barriers. Mismatch distribution analysis, neutrality tests and Bayesian skyline plots revealed that a significant population expansion occurred for the total population and Clade W, with horizons dated to approximately 0.08 and 0.07 Mya, respectively. These results suggest that the population expansion of Taiwan Island species B. bankorensis might have resulted from the release of available habitat in post-glacial periods, the genetic variation on mtDNA showing habitat selection, subsequent population dispersal, and co-distribution among clades.ConclusionsThe multiple origins (different clades) of B. bankorensis mtDNA sequences were first evident in this study. The divergent genetic clades found within B. bankorensis could be independent colonization by previously diverged lineages; inferring B. bankorensis originated from B. gargarizans of mainland China, then dispersal followed by isolation within Taiwan Island. Highly divergent clades between W and E of B. bankorensis, implies that the CMRs serve as a genetic barrier and separated the whole island into the western and eastern phylogroups.

Genetic structure of Bufo bankorensis distinguished by amplified restriction fragment length polymorphism of cytochrome b

Abstract Background Bufo bankorensis is an endemic species in Taiwan, and its populations are geographically and reproductively isolated. However, the distinction of Taiwanese B. bankorensis as a separate species from the Chinese Bufo gargarizans remains in dispute. Results A primer set was designed to explore the mitochondrial (mt)DNA cytochrome (Cyt) b sequence (700 bp) of B. bankorensis in 148 individuals collected from 12 locations in Taiwan. After a polymerase chain reaction and sequencing, we found that the nucleotide sequence of Cyt b contained two restricted enzyme sites of Bam HI and Tsp RI. Following Bam HI enzyme digestion, samples of B. bankorensis were divided into two clades: western (which were undigested) and eastern (which were digested) clades. Additionally, Cyt b of the western clade of B. bankorensis was not cut by Bam HI, while it was cut by Tsp RI into two sublineages. The result infers that at least two broadly divergent phylogroups of B. bankorensis exist in Taiwan and are not morphologically distinguishable. Based on the divergent sequence of Cyt b and cutting restriction enzymes, these populations were classified into three distinct phylogroups. Conclusion Genetically, one (western group 1, uncut by Bam HI and cut by Tsp RI) is most likely B. gargarizans, a second one (western group 2, uncut by both Bam HI and Tsp RI) is B. bankorensis, and a third one (eastern clade, cut by Bam HI but not cut by Tsp RI) could be a new subspecies. All three phylogroups were found in some areas, suggesting that they are sympatric, not allopatric.

Effects of construction materials and design of lake and stream banks on climbing ability of frogs and salamanders

With the increasing development of many areas in recent years, concrete structures are often installed along water bodies in order to protect the safety of local residents. However, effects of these concrete structures on environments and mobility of amphibian species are still unknown. The construction of concrete banks along rivers associated with human development has become a serious problem in Taiwan. Most ecosystems used by amphibians are lakes and stream banks, yet no related design solutions to accommodate the needs of amphibians have been used in Taiwan. In this research, we selected eight species of amphibians and investigated their climbing abilities in an effort to improve lake and river bank designs. We evaluated their climbing abilities on five angles of bank slopes, identified relationships between an amphibian's climbing ability and different surface substrates of banks, i.e. Japanese silvergrass ( Miscanthus floridulus) mixed with moss, cobblestone, wood ( Philippine mahogany), clay, and concrete, under high humidity and different temperatures to simulate changes across the four seasons. The results showed that climbing ability of these amphibians is slightly decreased at low temperatures. For example, on a 45° slope in winter, the average climbing ability decreased 8% from results in summer. The upper limit of bank design slope suitable for Hynobius arisanensis on rock and wood surfaces is 45°. For amphibians from alpine areas in Taiwan, such as Bufo bankorensis, the maximum suitable slope is 15°. With concrete as the water bank material, slopes <30° are preferable. The results presented here can serve as a reference for technicians involved in future ecological engineering designs of banks throughout the world.

Ingested Energy Differs between Populations of the Toad Bufo bankorensis from Different Altitudes

We measured ingested energy (E(i)) and apparent digestibility efficiency (ADE) in two populations of Bufo bankorensis from different altitudes at three temperatures and during two seasons to test the hypothesis that the optimal temperature range (T(opt)) for E(i) and ADE has shifted to the lower range in highland toads and winter toads. The T(opt) for E(i) was 22 degrees C for the lowland and highland toads and did not vary between seasons, thus falsifying the hypothesis. ADE of the toads was 96%-99% at 15 degrees -30 degrees C, and there was no difference between populations or seasons. Furthermore, when fed with fast-moving prey, the toads from both altitudes had similarly low E(i) at 15 degrees C; when fed with slow-moving prey, the highland toads increased E(i) at 15 degrees C, but the lowland toads did not. These results suggest that the toads from different altitudes had different appetites, even though their feeding locomotion was hampered in both populations at low temperatures.

Toads (Bufo bankorensis) influence litter chemistry but not litter invertebrates and litter decomposition rates in a subtropical forest of Taiwan

Few studies have been conducted to investigate ecological roles of litter amphibians in forest ecosystems. In this study, ten field enclosures (3 m × 2 m × 0.4 m) were used to evaluate effects of the toad Bufo bankorensis on the abundance of litter invertebrates (microbivores, fragmenters and predatory arthropods) and litter decomposition rates in a subtropical forest of southern Taiwan. Litterbags collected from toad and control (toad-excluded) enclosures were analysed for the communities and abundances of litter invertebrates and decay loss during this decomposition study from September to December 2001. The presence of B. bankorensis significantly changed phosphorus concentrations in the litter, but not the densities of litter invertebrates (microbivores, fragmenters and predatory arthropods) or rates of litter decomposition. These results were not consistent with previous studies, which have shown that Plethodon cenereus in a temperate forest of north-east USA and Eleutherodactylus coqui in a tropical rain forest of Puerto Rico significantly changed decomposition rates. We suggest that ecological roles of ground-dwelling amphibians may be species-specific and vary with different terrestrial ecosystems.

Temperature and humidity alter prolactin receptor expression in the skin of toad (Bufo bankorensis and Bufo melanostictus)

Bufo bankorensis and Bufo melanostictus, the only two species of Bufonidae genus in Taiwan, live in habitats that differ in altitude and humidity. This study tested the hypothesis that prolactin receptor (PRLR) expression responds to environmental change. Western blot analysis showed that the PRLR protein was widely distributed in brain, lung, liver, kidney, dorsal skin and ventral skin of toads. The level PRLR protein was elevated in the dorsal skin of the two toad species treated with dry or wet conditions for 14 days. The increase in PRLR of dorsal skin in B. bankorensis was higher than that in B. melanostictus. This experimental result suggests that B. bankorensis secretes more mucus to reduce water evaporation from its thinner cuticle than B. melanostictus. The expression of PRLR protein was increased in the lung of B. bankorensis and decreased in the lung of B. melanostictus. Moreover, PRLR protein levels were increased in the kidneys in the two species toad, likely due to reduction in water lost through lung and urine. The two toad species were subjected to varying temperatures (25 degrees C, 15 degrees C and 10 degrees C) for 14 days. The lowest PRLR protein expression was observed at 10 degrees C. Comparison of the decreasing trend in PRLR protein levels demonstrated that the variation in B. bankorensis was significantly higher than that in B. melanostictus. Comparisons of variation in PRLR protein expression in the two species under different environments suggest that B. bankorensis is more adaptable to different environments than B. melanostictus.

Reproductive Characteristics of Bufo bankorensis at Two Elevations in Taiwan

We compared the reproductive characteristics of two populations of Bufo bankorensis in central Taiwan, one inhabiting a temperate climate (Meifong, 2100 m), the other inhabiting a subtropical climate (Wushe, 1100 m). We determined ovary status, spermatogenetic activity, fat body and liver mass cycles, and plasma 17-betaestradiol and androgen levels over a 14 month period. B. bankorensis from both populations are prolonged breeders but the temperate population exhibits breeding activity throughout the year, while the subtropical population only breeds from September to March. Their spermatogenic cycles are continuous, and their spermatogenetic activities are invariably at stage 6, in which spermatozoa are predominant in the seminiferous tubule. Both populations show monthly variations in plasma androgen and 17-betaestradiol levels, but follow different patterns. Ovary mass is larger in the temperate than in the subtropical population. The reproduction differences of two elevation toads could be reflected by adaptations to the local environmental regimes of its habitat. The reproductive patterns of these populations of Bufo bankorensis are also compared to those of sympatric and allopatric populations of five anurans studied from sites throughout Taiwan.

Metabolic and ventilatory responses to hypoxia in two altitudinal populations of the toad, Bufo bankorensis

Effects of hypoxia on resting oxygen consumption ( M ̇ O 2 ), lung ventilation, and heart rate at different ambient P O 2 were compared between lowland and high altitude populations of the toad, Bufo bankorensis. Resting M ̇ O 2 decreased significantly in mild hypoxia (P O 2 =120 mm Hg) at 10°C and in moderate hypoxia (P O 2 =80 mm Hg) at 25°C in both altitudinal populations; however, resting M ̇ O 2 did not differ significantly between the two populations. Numbers of lung ventilation periods (VP) and total inspired volume ( V L) did not change with P O 2 at 10°C, but did increase at moderate and severe hypoxia (40 mm Hg), respectively, at 25°C. Resting heart rates did not change during hypoxia and did not differ between altitude populations. The results suggest (1) the effect of P O 2 change on M ̇ O 2 should be considered in future studies involving transfer of anurans to a different altitude; and (2) the metabolic and ventilatory physiology in B. bankorensis does not compensate for the low temperature and P O 2 at high altitude.

Respiratory physiology in two altitudinal populations of the central Formosan toad, Bufo bankorensis

Respiratory physiology in two altitudinal populations of the central Formosan toad, Bufo bankorensis

Occurrence of marinobufotoxin and telocinobufotoxin homologs in the skin of Bufo bankorensis BORBOUR.

The occurrence of marinobufagin 3-succinyl-L-arginine and 3-glutaryl-L-arginine esters, and telocinobufagin 3-glutaryl-L-arginine ester, together with seven known bufogenins, in the skin of Bufo bankorensis BORBOUR, is reported. The structures were elucidated by degradative means and/or direct comparison with authentic samples. These compounds were assayed for inhibitory activity towards guinea pig heart Na+, K+-adenosine triphosphatase.