Academic literature on the topic 'Cane toads'
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Journal articles on the topic "Cane toads"
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Webb, Jonathan K., David Pearson, and Richard Shine. "A small dasyurid predator (Sminthopsis virginiae) rapidly learns to avoid a toxic invader." Wildlife Research 38, no. 8 (2011): 726. http://dx.doi.org/10.1071/wr10206.
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Context Invasive species are a leading cause of extinctions, yet predicting their ecological impacts poses a formidable challenge for conservation biologists. When native predators are naïve to invaders, they may lack appropriate behaviours to deal with the invader. In northern Australia, the invasion of the highly toxic cane toad (Rhinella marina) has caused serious population declines of reptilian and mammalian predators that are ill equipped to deal with toad toxins. Cane toads recently invaded the Kimberley region of Western Australia, where they potentially threaten several species of small dasyurid predators. Aims We investigated whether red-cheeked dunnarts (Sminthopsis virginiae) attack cane toads, and if so, whether individuals subsequently learn to avoid toads as prey. Methods We quantified feeding and learning behaviours in toad-naïve red-cheeked dunnarts from the north Kimberley in Western Australia. Key results All toad-naïve dunnarts attacked toads during their first encounter. Most dunnarts bit the toad on the snout, killed it by biting the cranium, and consumed the toad snout-first, thereby initially avoiding the toad’s parotoid glands. Most dunnarts partially consumed toads before discarding them, and only one animal showed visible signs of toad poisoning. All dunnarts rapidly learnt to avoid toads as prey after one or two encounters. Predators rejected toads as prey for the duration of the study (22 days), suggesting long-term retention of the knowledge that toads are noxious. Conclusions Our results show that red-cheeked dunnarts rapidly learn to avoid cane toads as prey. Implications Our study was limited by small sample sizes, but our results suggest that small dasyurids can adapt to the cane toad invasion via taste aversion learning.
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Britton, Adam R. C., Erin K. Britton, and Clive R. McMahon. "Impact of a toxic invasive species on freshwater crocodile (Crocodylus johnstoni) populations in upstream escarpments." Wildlife Research 40, no. 4 (2013): 312. http://dx.doi.org/10.1071/wr12215.
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Context Spread of the invasive cane toad (Rhinella marina) across northern Australia is of concern. Predator species, including the freshwater crocodile (Crocodylus johnstoni), are susceptible to cane toad toxins when ingested. Upstream populations of freshwater crocodiles are smaller than downstream counterparts because of limited resources. We measured the impact of cane toad arrival on densities of these upstream populations. Aims Our aim was to determine whether the influx of cane toads had a negative impact on populations of upstream ‘stunted’ freshwater crocodiles. Methods Population surveys for crocodiles were conducted in three upstream creek systems, using day- and night-based survey methods, before the arrival of cane toads in the area. These surveys were repeated under similar conditions following the arrival of cane toads, to compare the distribution and densities of freshwater crocodiles and, hence, measure the impact of cane toads. Key results There were significant declines in crocodile density at two survey sites following the arrival of cane toads, and we found dead crocodiles and cane toad carcasses with crocodile bite marks. The third site showed no change in density. There was a decline in mean density across all sites from 3.0 crocodiles km–1 to 1.1 crocodiles km–1 following the arrival of cane toads. Conclusions There was an overall decrease in crocodile densities and a reduction in distribution following the arrival of cane toads into the survey area. Dead crocodiles and evidence of their having eaten cane toads strongly suggest that these declines were caused directly by the arrival of cane toads into the area. One site showed no apparent change other than an increase in wariness, which may reflect the distribution of available feeding and shelter resources among the three sites. Implications These results suggest that upstream freshwater crocodile populations are highly susceptible to cane toad toxins, and that impacts on their population can include local extirpation. Considering their morphological and possibly genetic distinctiveness, the loss of these unique populations is of conservation concern.
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Semeniuk, M., F. Lemckert, and R. Shine. "Breeding-site selection by cane toads (Bufo marinus) and native frogs in northern New South Wales, Australia." Wildlife Research 34, no. 1 (2007): 59. http://dx.doi.org/10.1071/wr06112.
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Previous research on cane toads (Bufo marinus) has documented non-random selection of breeding sites by this invasive species. In the wet–dry tropics of the Northern Territory, toads selected spawning sites in open areas with gently sloping banks and shallow water. If consistent, such biases may present opportunities for toad control via waterbody manipulation – but first we need to know whether such criteria for spawning-site selection (1) are consistent across other parts of the toad’s extensive Australian range, and (2) differ from those of native anurans breeding at the same waterbodies. We quantified the attributes of potential and actual spawning-sites in north-eastern New South Wales, in temperate-zone habitat where cane toads have been present for many decades; our study area thus differs in many ways from the previously studied tropical site. We compared habitat and water chemistry variables between 23 cane toad breeding sites and 23 nearby unused sites. To examine habitat use at an even finer scale, we conducted nocturnal surveys of microhabitat use by calling male toads and native anurans. Our results revealed that cane toads in this region were highly selective in their choice of breeding sites, and that the criteria they used in this respect were similar to those used by toads in the Northern Territory. Calling male cane toads also used microhabitats non-randomly within each pond, apparently based on similar criteria to those used when selecting among ponds. Toads differed significantly from native anurans in these respects, suggesting that it may be feasible to manipulate waterbody attributes to impact on invasive toads without disrupting reproduction by native anurans.
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Schwarzkopf, L., and R. A. Alford. "Acoustic attractants enhance trapping success for cane toads." Wildlife Research 34, no. 5 (2007): 366. http://dx.doi.org/10.1071/wr06173.
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Cane toads are an introduced pest in many tropical locations around the world, but, surprisingly, there are few methods available for their control. Highly effective trapping may provide a means of controlling toads, either alone or as part of an integrated pest-management scheme. Existing cane toad trap designs use lights to lure insects to traps, and toads enter the traps to feed. Using a large, outdoor experimental arena and playback of cane toad mating calls, we examined the possibility that cane toads, like many other anurans, are attracted to conspecific mating vocalisations. We found that both male and female toads were attracted to quiet (47dB(A) at 1 m) playbacks, whereas only males responded to loud (67dB(A) at 1 m) playbacks with phonotaxis. We also tested whether playbacks broadcast from traps would be useful attractants to traps in the field. We captured three times more toads in traps with playbacks than in traps without playbacks, suggesting that playbacks can be used to enhance trapping success for toads.
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Freeland, WJ, BLJ Delvinquier, and B. Bonnin. "Decline of Cane Toad, Bufo-Marinus, Populations - Status of Urban Toads." Wildlife Research 13, no. 4 (1986): 597. http://dx.doi.org/10.1071/wr9860597.
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Cane toads from an urban population in Townsville, Qld, exhibit poor body condition and small body size, as do toads in populations around Townsville which have declined in numbers. The small body size and poor condition are associated with a high food intake and a low rate of parasitism. The results suggest that decline of rural populations is not a product of parasitism, or food and or water shortages related to unusually adverse seasonal conditions. Populations of cane toads around Townsville declined more than 3 years before this study.
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Mayer, Martin, Gregory P. Brown, Barbara Zimmermann, Matthew J. Greenlees, and Richard Shine. "Habitat use of the introduced cane toad (Rhinella marina) and native frog species in tropical Australia." Journal of Tropical Ecology 31, no. 6 (September 17, 2015): 531–40. http://dx.doi.org/10.1017/s0266467415000474.
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Abstract:The ecological impacts of introduced species can reveal mechanisms underlying habitat selection and behaviour. We investigated the habitat use of native frog species and the invasive cane toads (Rhinella marina) in tropical northern Australia to measure overlap in habitat use, and to test if the presence of the cane toad influences frog behaviour. Native frog species and the cane toad both preferred habitats close to water and unvegetated holes. However, native frogs were found further from water (on average 19.4 m) than were toads (on average 12.6 m), and preferred areas with higher vegetation (8–50 cm) than did toads, which were more abundant in vegetation lower than 8 cm. For both types of anuran, the next neighbour was more often of the same type (89% in frogs, 52% in toads) than expected by chance (observed ratio: 75% frogs vs 25% toads), reflecting these differences in habitat use. Our counts of frog abundance increased on average 14.5% in areas from which we removed cane toads temporarily. This result suggests that cane toads inhibit the activity of native anurans either by inducing avoidance, or by reducing activity. By modifying the behaviour and spatial distribution of native taxa, invasive cane toads may curtail activities such as feeding and breeding.
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Dall, David. "A Catastrophe of Cane Toads." Outlooks on Pest Management 22, no. 5 (October 1, 2011): 226–29. http://dx.doi.org/10.1564/22oct08.
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Thomas, Julian, Tristram Miall, and Mark Lewis. "Cane Toads: An Unnatural History." American Historical Review 96, no. 4 (October 1991): 1118. http://dx.doi.org/10.2307/2165000.
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N. Reed, Robert, Kristin A. Bakkegard, Glenn E. Desy, and Sheldon M. Plentovich. "Diet composition of the invasive cane toad (Chaunus marinus) on Rota, Northern Mariana Islands." Pacific Conservation Biology 13, no. 3 (2007): 219. http://dx.doi.org/10.1071/pc070219.
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The cane or marine toad (Chaunus marinus, formerly Buto marinus) was introduced to the Northern Mariana Islands starting in the 1930s. The effects of this exotic predator on native vertebrates (especially lizards) are largely unknown. We analysed the stomach contents of 336 cane toads collected from the island of Rota, with the goal of estimating the level of toad predation on native vertebrates. Beetles, ants, millipedes, and grasshoppers/crickets comprised the majority of prey classes consumed by toads. The introduced Brahminy blindsnake (Ramphotyphlops braminus; N = 6) and conspecific cane toads (N = 4) were the vertebrates most commonly found in toad stomachs. Skinks (Emoia; N = 2) were the only native vertebrates represented in our sample. The small numbers of nocturnal terrestrial vertebrates native to Rota likely translates to relatively low rates of predation by cane toads on native vertebrates.
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KELEHEAR, C., J. K. WEBB, and R. SHINE. "Rhabdias pseudosphaerocephala infection in Bufo marinus: lung nematodes reduce viability of metamorph cane toads." Parasitology 136, no. 8 (June 15, 2009): 919–27. http://dx.doi.org/10.1017/s0031182009006325.
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SUMMARYCane toads (Bufo marinus) were introduced to Australia in 1935 and have since spread widely over the continent, generating concern regarding ecological impacts on native predators. Most Australian cane toad populations are infected with lung nematodes Rhabdias pseudosphaerocephala, a parasite endemic to New World (native-range) cane toad populations; presumably introduced to Australia with its toad host. Considering the high intensities and prevalence reached by this parasite in Australian toad populations, and public ardour for developing a control plan for the invasive host species, the lack of experimental studies on this host-parasite system is surprising. To investigate the extent to which this lungworm influences cane toad viability, we experimentally infected metamorph toads (the smallest and presumably most vulnerable terrestrial phase of the anuran life cycle) with the helminth. Infected toads exhibited reduced survival and growth rates, impaired locomotor performance (both speed and endurance), and reduced prey intake. In summary, R. pseudosphaerocephala can substantially reduce the viability of metamorph cane toads.
Dissertations / Theses on the topic "Cane toads"
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Phillips, Ben Lee. "Evolution and impact of invasive species : cane toads and snakes in Australia." University of Sydney. School of Biological Sciences, 2004. http://hdl.handle.net/2123/611.
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Evolution can occur rapidly, along timescales that are traditionally regarded as 'ecological'. Despite growing acceptance among biologists of rapid evolution, a strong paradigm of contemporary evolution is still absent in many sub-disciplines. Here I apply a contemporary evolution viewpoint to conservation biology. Specifically, I examine the impact of cane toads (Bufo marinus) on Australian snakes. Toads were introduced into Australia in 1935, have spread rapidly and represent a novel, extremely toxic prey item to na�ve Australian predators (including snakes). Based on dietary preferences and geographic distributions I find that 49 species of Australian snake are potentially at risk from the invasion of the toad. Furthermore, examination of physiological resistance to toad toxin in 10 of these �at risk� species strongly suggests that most species of Australian snake are poorly equipped to deal with a likely dose of toad toxin. Even species that are highly resistant to toad toxin (such as the keelback, Tropidonophis mairii) face indirect fitness costs associated with consuming toads. Within a population of snakes however, the impact of toads is unlikely to be random. For example, the examination of several component allometries describing the interaction between snakes and toads revealed that, within a species, smaller snakes are more likely to ingest a fatal dose of toad toxin than are larger snakes. Further consideration of the interaction between snakes and toads suggests that toads will not only be exerting differential impact on snakes based upon morphology, but also exert non-random selection on prey preference and resistance to toad toxin in snake populations. To examine the possibility of a morphological response by snakes to toads, I examined changes in the body size and relative head size of four species of snake as a consequence of time since exposure to toads. Two of the species (green treesnakes and red-bellied blacksnakes) are predicted to face strong impacts from toads. These two species showed an increase in mean body size and a decrease in relative head size as a consequence of time since exposure to toads; both changes in an adaptive direction. In contrast, the other two species (keelbacks and swampsnakes) are predicted to face much lower impact from toads, and these two species showed little or no evidence of morphological change associated with time since exposure to toads. These results indicate an adaptive change in morphology at a rate that is proportional to the predicted level of impact for each species, strongly suggesting an evolved response. Red-bellied blacksnakes (a toad-vulnerable species) were further assessed for evolved responses in prey preference and toxin resistance. Comparisons between toad-exposed and toad-na�ve populations of blacksnakes revealed that snakes from toad-exposed populations exhibited slightly higher resistance to toad toxin and a much-reduced tendency to eat toads, when compared with toad-na�ve snakes. Na�ve snakes exhibited no tendency to learn avoidance of toxic prey, nor were they able to acquire resistance to toxin as a result of several sub-lethal doses, suggesting that the observed differences between populations is evolved rather than acquired. Together, these results strongly suggest that blacksnakes are exhibiting an evolved shift in prey preference and toxin resistance as a consequence of exposure to toads. Thus, it appears that snakes are exhibiting adaptation at multiple traits in response to exposure to toads. Given the high likelihood that these adaptive shifts have an evolved basis, it appears that the impact of toads will decrease with time in many snake populations. But what about toads? Because the outcome of the interaction between a toad and a snake is also mediated by the body size and relative toxicity of toads, it is important to understand how these traits vary in space and time. Exploratory analysis revealed that toads exhibit a decrease in body size and a decrease in relative toxicity as a consequence of time since colonisation, indicating that their impact on native predators decreases with time. Additionally, there appears to be meaningful spatial variation in toad relative toxicity, indicating that some populations of native predators are facing higher impact from toads than others. Overall, these results clearly indicate the importance of assessing the potential for rapid evolutionary response in impacted systems. Doing so may provide evidence that some species are in less trouble than originally thought. Additionally, and as more data accumulate, it may be possible to characterise certain categories of environmental impact by their potential for eliciting adaptive response from �impacted� species. This approach has strong implications for the way conservation priorities are set and the way in which conservation dependent populations are managed.
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Phillips, Ben L. "Evolution and impact of invasive species cane toads and snakes in Australia /." Connect to full text, 2004. http://hdl.handle.net/2123/611.
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Thesis (Ph. D.)--University of Sydney, 2005.Title from title screen (viewed 20 May 2008). Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the School of Biological Sciences, Faculty of Science. Degree awarded 2005; thesis submitted 2004. Includes bibliographical references. Also available in print form.
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McCann, Samantha. "Using pheromonal cues to control invasive cane toads (Rhinella marina) in Australia." Thesis, The University of Sydney, 2018. http://hdl.handle.net/2123/18712.
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Cane toads, Rhinella marina, were brought to Australia in 1935. The toads spread rapidly, and currently are found over more than 1.2 million km2 of tropical and sub-tropical Australia. Cane toads have had devastating impacts on Australian wildlife, largely due to the vulnerability of predators to the toads’ toxins. As toads continue to spread, we urgently need to develop management strategies to reduce the impact of toads on native fauna. Two new aquatic-based methods of cane toad control show great promise. First, traps that exploit the chemical attraction of toad tadpoles to conspecific eggs (a cannibalistic response) can be used to remove toad tadpoles from waterbodies. Secondly, a ‘suppression cue’ involves the suppression of toad eggs and hatchlings by older conspecific tadpoles. Although both strategies work well under lab conditions, unanswered questions include how the mechanisms function under different environmental conditions, how chemical cues interact, and the feasibility of using these methodologies in the field. My thesis addresses these questions. I ran extensive lab-based tadpole trapping trials to investigate how the effectiveness of trapping is altered by factors such as temperature, tadpole developmental stage, and toxin and tadpole geographic origin. I investigated whether exposure to one chemical cue affects the response of tadpoles to other cues, and I ran mesocosm trials to determine whether removing some (but not all) of the cane toad tadpoles from a waterbody increases the viability of survivors. To determine whether ‘suppression’ can successfully be transferred to the field, I ran trials in field ponds. Finally, I investigated the way in which cane toads are able to invade areas that are theoretically considered ‘too cold’ for the species to persist. My thesis documents the ways in which the success of aquatic-based cane toad control methodologies can be maximised, and how lab-based trials might translate into effective field practices.
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Pettit, Lachlan. "The long-term impacts of invasive cane toads on reptilian predators in Australia." Thesis, University of Sydney, 2020. https://hdl.handle.net/2123/24545.
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The near-extirpation of varanid lizards by Cane Toads has severely impacted ecosystem processes. Given the critical roles of apex predators in regulating ecosystem function, and the massively negative impacts of toads on populations of large goannas, we need to know the time-course of such effects. Limited data suggest that goanna populations eventually recover (e.g., in northeastern Queensland, where toads have been present for several decades) – but we know almost nothing about the nature or rate of such recovery. To develop robust priorities for conservation management, we need to understand how monitors adjust to Cane Toads over time.
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Lie, Clarencia. "Molecular Detection and Characterisation of Entamoeba species in Australian Cane Toads (Rhinella marina) and Australian Native Snakes." Thesis, University of Sydney, 2020. https://hdl.handle.net/2123/23176.
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One of Australia’s infamous pest, cane toads, were found to be infected with potentially pathogenic protozoan parasite within the genus of Entamoeba. It was reported that a number of cane toads in Northern Territory population was presented with gastrointestinal disease and therefore is the first agent of disease to be described in cane toads, causing morbidity and mortality. With its invasion dynamic, ecological relationship, and impact of cane toads on Australian native fauna still under evaluation, first report of entamoebiasis in cane toads is an emerging wildlife disease. This thesis is a part of investigation into the significance and impact of novel Entamoeba sp. CT1 and Entamoeba ranarum found in Australian native fauna and cane toad populations. This thesis focuses on two aspects: one is on the technical aspect of diagnostic of Entamoeba species of cane toads and native fauna, and the other is on the molecular analysis of the SSU-rRNA gene for identification and taxonomy of Entamoeba. This thesis evaluates the application of various methods of diagnostic of Entamoeba in faecal and colon of wild cane toads. Methods evaluated include direct wet mount, histology, conventional PCR and real-time PCR, where recommendations on future clinical diagnosis and epidemiological studies were made based on this evaluation. In order to investigate the distribution of Entamoeba in wild native fauna, non-invasive faecal detection of Entamoeba was implemented onto native snake populations that share prey and predatorial relationship with cane toads. Steps taken to obtain and analyse complete sequences (SSU-rRNA gene) of Entamoeba species was described and used to infer evolutionary relationship of the Entamoeba species of interest. Comparative data on performance of each diagnostic method for detection of Entamoeba (colon and faecal) in cane toads were obtained. For the purpose of non-invasive method of diagnosis (faecal detection), this thesis provided evidence for the use of molecular-based assays (real-time PCR and conventional PCR) as the recommended approach. By implementing this approach, this study was able to provide firsthand evidence for the presence of Entamoeba ranarum in faecal samples of wild keelback snakes. Molecular analyses of 18S rRNA gene of Entamoeba species in cane toads and snakes placed the two species well into the amphibian/reptilian clade and further expand the knowledge on Entamoeba genetic diversity.
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Wijethunga, Magammanage Uditha Indeewari. "Hopping south: how will cane toads deal with the challenges arising from their invasion of NSW?" Thesis, The University of Sydney, 2015. http://hdl.handle.net/2123/14366.
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Invasive species threaten biodiversity on a global scale, stimulating extensive research not only on the impacts of these species, but also on the factors that constrain invader distributions. To answer that latter question, we need to understand the developmental plasticity of a given invasive species in response to novel abiotic and biotic challenges. The Cane toad (Rhinella [Bufo] marina) is a large, toxic anuran, native to South and Central America that was introduced to Australia in a futile attempt to control agricultural pests. Since their introduction in 1935, toads have spread west from north Queensland across tropical Australia and south into New South Wales. Extensive research shows that toads have rapidly evolved an increased rate of dispersal across the Australian tropics, and exhibit physiological and behavioural adaptations to arid regions. However, the southern front of the toad invasion into New South Wales has attracted less study. Toads in this area face novel challenges, both biotic and abiotic. Models of the potential distribution of toads in New South Wales have ignored the potential for toads to adapt to lower temperatures, or to other abiotic challenges such as salinity and acidity. Such plasticity could influence the eventual geographic distribution of toads - and hence, their impact on native species. I focused on the egg and larval stages of the life history (rather than later terrestrial stages, the focus of most previous research). Thus, I conducted field surveys to measure abiotic conditions in potential spawning ponds near the current invasion front in northern New South Wales. I found wide variation in pH (3.9 to 9.8) and salinity (0 to 1200 ppm [3.5% the salinity of seawater]) among natural waterbodies. Temperatures in available ponds averaged around 20°C during the breeding period, 10°C lower than in many areas of the toads’ native range, or in the Australian tropics. I then conducted laboratory studies to evaluate the toads’ response to these conditions. Broadly, I found that early life stages of Cane Toads are resilient and can deal with relatively extreme abiotic conditions. Hatching success of eggs was high at low pH (down to pH 4.0), whereas rates of tadpole survival, growth, and development were enhanced by higher pH. Eggs and tadpoles tolerated the most saline conditions I found in potential spawning ponds during surveys. Indeed, high-salinity treatments increased tadpole body sizes, accelerated metamorphosis, and improved locomotor ability of metamorphs (but did not affect metamorph morphology). At very low salinity (40 ppm [0.1% seawater]), eggs hatched but larvae did not develop past Gosner stage 37. Paradoxically, lower water temperatures may enhance rather than reduce recruitment of cane toads, at least in areas where pond temperatures reach or exceed 20°C. Cane toad eggs and larvae died at 16°C, but hatching success and larval survival rates were higher at 20°C than in warmer conditions. Lower temperatures slowed growth rates, increasing the duration of tadpole life; but also increased metamorph body mass (and influenced metamorph body shape and locomotor performance). However, comparisons of cane toads from two geographic regions (tropical and temperate) revealed no divergence in cold-tolerance, despite the major difference in mean water temperatures between tropical versus temperate regions. Overall, my data reveal that embryonic and larval life stages of R. marina can successfully tolerate the wide range of acidity, salinity and thermal conditions that they are encountering in this new part of their range in northern New South Wales. I also examined one novel biotic challenge in this area. Cane Toads are encountering an invasive predatory fish (Mosquito Fish, Gambusia holbrooki) that, like the toad, has an American origin. I tested the responses to toad tadpoles of Mosquito Fish from populations that were sympatric versus allopatric with cane toads. Toad-sympatric fish generally ignored toad tadpoles, whereas toad-allopatric fish initially consumed a few tadpoles, but rapidly developed an aversion to these toxic prey items. The laboratory-reared progeny of these fishes differed in their propensity to approach toad tadpoles as potential meals, but not in the rate at which they learned toad-avoidance. Thus, Mosquito Fish show an innate aversion to cane toad tadpoles (presumably reflecting coevolution), as well as an ability to rapidly learn taste-aversion. As a result, any impact of Mosquito Fish on Cane Toads (and vice versa) is likely to be transitory. Overall, my study shows that the egg and larval life-stages of cane toads can tolerate wide variation in the biotic and abiotic conditions of natal ponds, and that their responses to the conditions found in northern New South Wales are likely to facilitate rather than constrain continued southwards expansion of the toad invasion front in eastern Australia. I also conducted a separate experiment, to test a more general idea. My finding that low pH enhances hatching rates of toad eggs suggested a novel hypothesis: that the benefit of spawning after heavy rain (as seen in many anurans) may reflect impacts of transitory changes in pond water pH. To test this idea, I measured feeding rates of two predators of toad eggs (Mosquito Fish and conspecific toad tadpoles) at a range of pH conditions. Predation rates on eggs likely are lower following heavy rain that reduces pond pH, and the effect may last long enough to allow eggs to hatch into mobile larva more capable of evading predators. Thus, anurans may benefit by spawning as soon as heavy rain when reduces the threat that predators pose to newly-laid eggs.
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Clarke, Gregory Stephen. "The Evolution of Competitive Ability Across a Biological Invasion: A Study of Cane Toads in Tropical Australia." Thesis, The University of Sydney, 2019. http://hdl.handle.net/2123/21083.
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Invasive species must adapt to a suite of novel selective pressures as they colonise new territory. For example, theory predicts that selective forces at an invasion front will favour traits that enhance rates of dispersal and population growth, whereas selective forces in the range-core will favour traits that enhance competitive ability. To explore this idea, I conducted competition trials on three life stages of the invasive cane toad (Rhinella marina) from invasion-front and range-core populations in tropical Australia. For larval and early terrestrial-stage animals, I conducted experiments whereby the offspring of invasion-front and range-core adults were placed into mesocosms to compete for limited resources. To enable such experiments, I developed a simple method to mark each cohort of tadpoles, with minimal observed effects on growth or survival. Range-core larvae proved to be better competitors than invasion-front larvae, as predicted by evolutionary theory. Contrary to expectations, invasion-front metamorphs outcompeted range-core metamorphs, growing larger and winning more food. For adults, I focused on the trade-off between rapid dispersal versus success in male-male rivalry. Longer arms reduced the force required to displace an amplecting male from a female. When competing for a female, males with longer arms had lower likelihoods of retaining amplexus. I also explored how visual and acoustic cues influence the behaviour of sexually active males. Male toads used the presence of a chorus to increase their activity levels and as a cue to initiate amplexus. Males also used movement to identify potential mates, with increased rates of amplexus when a target was moving. My thesis presents empirical evidence that the evolutionary forces unleashed by a biological invasion can modify traits important in intraspecific competition at each life stage. My results are relevant to evolutionary theory and are directly translatable into proposed management strategies.
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Zulfiker, Abu Hasanat Md. "Compound Identification and Functional Characterisation of Cane Toad Skin Extracts." Thesis, Griffith University, 2016. http://hdl.handle.net/10072/365733.
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Amphibians are storehouse of bioactive compounds. Among them, the skin of toad species is rich in biologically active compounds such as peptides, proteins, steroids, alkaloids and opioids. Some of these compounds have found significant therapeutic applications, for example as antibacterials, antifungals, antiprotozoals, antidiabetics, antineoplastics, analgesics and sleep inducing agents. In Traditional Chinese Medicine (TCM) aqueous extracts of Chinese toad skins have been used for centuries to treat pain, swelling, heart failure and several types of cancer with minimal to no side effects, generating a 10 billion USD market in China. Numerous compounds have been identified from these Chinese toad skin extracts, which have reported therapeutic activities in various disease conditions, either as a single compound or as a group of compounds. In Traditional Korean Medicine, toad extracts have also been reported to show potential activity against anxiety and depression. In Australia and America cane toad skins have a history of recreational use for euphoric purposes. This information coupled with knowledge of its use in China and Korea enabled us to hypothesise that Queensland cane toad skin extracts would likely contain similar ‘biologically-active’ compounds in selective extracts. This thesis reports on research work carried out to identify such ‘biologically-active’ extracts and/or compounds, then functionally characterise these in cultured cells for investigation of their therapeutic relevance to neuropsychiatric disorders, especially in obsessive compulsive disorder (OCD) - potentially identifying potent therapeutics for future development.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Medical Science
Griffith Health
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Qi, Ji. "Cane Toad Skin Extracts as Anti-Inflammatory and Anti-Cancer Agents." Thesis, Griffith University, 2016. http://hdl.handle.net/10072/365729.
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The skin of the toads is known to be rich in bufadienolide compounds (a group of cardiac glycosides) that exhibit antitumor activity. For example, Huachansu (Cinobufacini), the aqueous extracts from the dried toad skin of Bufo bufo gargarizans Cantor or Bufo melanostictus Schneider, has been widely used in clinical therapy for various cancers in China. Clinical data have indicated that Cinobufacini may have significant anticancer activity with low toxicity and few side effects. Data to date suggest that treatment with Cinobufacini may also enhance the quality of life for patients with cancer. Huachansu contains several groups of compounds including peptides, bufadienolides/cardiac glycosides, cholesterols, indole alkaloids, bufogargarizanines, organic acid, and others. Bufadienolides, such as bufalin, cinobufagin, resibufogenin, and telocinobufagin, are responsible for the anti-cancer properties of Huachansu through disruption of the cell cycle and consequent inhibition of cell proliferation, induction of apoptosis, suppression of the NF-B pathway, immunomodulation and reversal of multi-drug resistance. The Australian cane toad (Bufo marinus) is also known as a source of bufadienolides, therefore is also considered as a new source of candidate lead compounds for drug development. Previous studies have shown that cane toad skin aqueous extracts (CTSAE) exhibited a stronger cardiac glycosides-like activity than the extracts of other organic solvents and have a suppression effect on Na+, K+‐ATPase in experimental models. However, no assay was performed to clarify the chemical constituents and pharmaceutical effects of CTSAE on cancer cells in previous studies.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Medical Science
Griffith Health
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Kosmala, Georgia Karoline. "Evolution of physiological traits in the invasive cane toad (Rhinella marina)." Thesis, The University of Sydney, 2018. http://hdl.handle.net/2123/18842.
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Cane toads are native to warm humid landscapes of the Americas, but since its introduction to Australia, the rapid geographic spread has exposed toads to climatic conditions well outside those of the native range, with many Australian sites hotter and seasonally drier than those in which the species evolved. I investigated the impacts of temperature and hydration on aspects of dispersal behaviour and physiological traits of toads, to clarify the ways in which toads may have changed as a result of encountering novel environments within their invaded range, by comparing populations within the native range (Brazil) to ones introduced to Hawai’i and Australia. When stimulated to run at high or low temperatures, or when dehydrated, Australian toads exhibited greater performance endurance than either Brazilian or Hawai’ian toads. When raised under the same conditions, toads whose parents were collected from the climatic challenging area of Western Australia exhibited better performance than the offspring of Queensland toads. Rates of evaporative water loss, skin resistance and rehydration showed that toads from eastern Australia had higher skin resistance to water loss whereas Brazilian toads had faster rehydration rates, suggesting a shift in water balance strategy after toads were introduced to Australia. Histological examination of the skin structure showed that Australian toads have thinner skin than do native-range conspecifics. Laboratory trials revealed that toads from Townsville heated faster than toads from northwestern Australian populations, especially when deprived of water. When exposed to extreme heat or desiccation, Brazilian toads exhibited higher levels of corticosterone and of heat-shock protein 70 than Australian toads, suggesting a more reactive stress response. My studies clarify some of the mechanisms that have allowed cane toads to colonize diverse areas that impose climatic challenges not present within the species’ native range.
Books on the topic "Cane toads"
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Australia's Cane toads: Overrun! New York, New York: Bearport Publishing, 2016.
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Lewis, Stephanie. Cane toads: An unnatural history. New York: Doubleday, 1989.
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Flint, David. The cane toad republic. Kent Town, S. Aust: Wakefield Press, 1999.
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Lawson, Walter J. The cane toad, Bufo marinus: A bibliography. Nathan, [Brisbane], Queensland: School of Australian Environmental Studies, Griffith University, 1987.
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Christopher, Lever. The cane toad: The history and ecology of a successful colonist. Otley: Westbury Academic and Scientific Publishing, 2001.
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Natarajan, T. S. Health status of Todas in Nilgiris: An appraisal. Thanjavur, Tamil Nadu, India: Tamil University, 1994.
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Carbonel, Juan Carlos. Todas las soluciones a sus problemas de piel. Buenos Aires: Obelisco, 1996.
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Toja, Olivia. Mamá debutante: ¡la guía que todas las jóvenes esperaban! México: Editorial Trillas, 2013.
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El libro del embarazo: Todas tus preguntas y las respuestas de los especialistas. Buenos Aires: Albatros, 2008.
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Arnold, Lobel. Adventures of Frog and Toad. 2nd ed. New York: Barnes & Noble Books, 2008.
Find full textBook chapters on the topic "Cane toads"
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Robin, Libby. "Cane toads as sport." In Animals Count, 15–25. Abingdon, Oxon ; New York, NY : Routledge, 2018. | Series: Routledge environmental humanities: Routledge, 2018. http://dx.doi.org/10.4324/9781351210645-3.
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Lewis, Mark. "Cane Toads: An Unnatural History." In 100 Documentary Films, 27–28. London: British Film Institute, 2009. http://dx.doi.org/10.1007/978-1-84457-551-0_11.
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Seabrook, Wendy. "CANE TOADS — A CRITICISM OF RESEARCH DIRECTIONS." In Herpetology in Australia, 184–85. P.O. Box 20, Mosman NSW 2088, Australia: Royal Zoological Society of New South Wales, 1993. http://dx.doi.org/10.7882/rzsnsw.1993.027.
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Rollins, Lee A., Mark F. Richardson, and Richard Shine. "A GENETIC PERSPECTIVE ON RAPID EVOLUTION IN CANE TOADS (RHINELLA MARINA)." In Invasion Genetics, 313–27. Chichester, UK: John Wiley & Sons, Ltd, 2016. http://dx.doi.org/10.1002/9781119072799.ch18.
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Beard, Karen H., Steve A. Johnson, and Aaron B. Shiels. "Frogs (Coqui Frogs, Greenhouse Frogs, Cuban Tree Frogs, and Cane Toads)." In Ecology and Management of Terrestrial Vertebrate Invasive Species in the United States, 163–92. Boca Raton : Taylor & Francis, 2018. | “A CRC title, part of the Taylor & Francis imprint, a member of the Taylor & Francis Group, the academic division of T&F Informa plc.”: CRC Press, 2017. http://dx.doi.org/10.1201/9781315157078-9.
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Jernelöv, Arne. "Marine (Cane) Toad on Pacific Islands." In The Long-Term Fate of Invasive Species, 197–215. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-55396-2_14.
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Hu, Wen, Nirupama Bulusu, Thanh Dang, Andrew Taylor, Chun Tung Chou, Sanjay Jha, and Van Nghia Tran. "Cane Toad Monitoring: Data Reduction in a High Rate Application." In Wireless Sensor Networks, 193–222. Boston, MA: Springer US, 2010. http://dx.doi.org/10.1007/978-1-4419-5834-1_7.
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Newton, Peter W., Peter W. G. Newman, Stephen Glackin, and Giles Thomson. "Transport and Urban Fabrics: Moving from TODs to TACs with Greyfield Regeneration." In Greening the Greyfields, 89–103. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-6238-6_4.
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AbstractThis chapter will focus on how new transit technology and corridor-regeneration policies can help transition greyfields. It builds on Chap. 10.1007/978-981-16-6238-6_3, which outlined the new distributed green technologies and their potential to help with urban regeneration in the greyfields at precinct scale. Transport systems are the sole focus of this chapter, as they have a very specific ability to help with urban regeneration via transit-activated GPR, given that accessibility is probably the largest city-shaping mechanism.
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"Cane toad wars." In Cane Toads, 173–84. Sydney University Press, 2013. http://dx.doi.org/10.2307/j.ctv1sjwpjh.17.
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"The cane beetles." In Cane Toads, 73–86. Sydney University Press, 2013. http://dx.doi.org/10.2307/j.ctv1sjwpjh.10.
Full textConference papers on the topic "Cane toads"
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Xie, Jie, Jinglan Zhang, Michael Towsey, and Paul Roe. "Long-term monitoring of cane-toads using acoustic sensors." In IPSN '17: The 16th International Conference on Information Processing in Sensor Networks. New York, NY, USA: ACM, 2017. http://dx.doi.org/10.1145/3055031.3055056.
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Silke, Andrew, and David Clayton. "Cane-Toad." In ACM SIGGRAPH 2003 video review. New York, New York, USA: ACM Press, 2003. http://dx.doi.org/10.1145/1006091.1006111.
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Konovalov, Dmitry A., Simindokht Jahangard, and Lin Schwarzkopf. "In Situ Cane Toad Recognition." In 2018 Digital Image Computing: Techniques and Applications (DICTA). IEEE, 2018. http://dx.doi.org/10.1109/dicta.2018.8615780.
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Thanh Dang, Nirupama Bulusu, and Wen Hu. "Lightweight acoustic classification for cane-toad monitoring." In 2008 42nd Asilomar Conference on Signals, Systems and Computers. IEEE, 2008. http://dx.doi.org/10.1109/acssc.2008.5074693.
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Hu, Wen, Nirupama Bulusu, Chun Tung Chou, Sanjay Jha, Andrew Taylor, and Van Nghia Tran. "A hybrid sensor network for cane-toad monitoring." In the 3rd international conference. New York, New York, USA: ACM Press, 2005. http://dx.doi.org/10.1145/1098918.1098970.
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Tang, J. M., and K. A. Shore. "Response of TOADs to Frequency Detuned Control and Signal Picosecond Pulses." In The European Conference on Lasers and Electro-Optics. Washington, D.C.: Optica Publishing Group, 1998. http://dx.doi.org/10.1364/cleo_europe.1998.cwf70.
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The optical switch known as the Terahertz Optical Asymmetric Demultiplexers (TOADs) is currently attracting a high degree of interest because of several key developments and new applications such as all-optical regenerative memory. However, rather little theoretical analysis of the operating characteristics of TOADs has been undertaken. Recently analysis which took into account the usual gain saturation and ultrafast intraband processes contributing to nonlinear gain compression, showed that threshold energy of TOADs can be decreased to less than 0.1pJ by matching the width of control pulse and switching window [1], and also that switching windows less than 1ps cannot be achieved in practice due to the effect of ultrafast intraband processes [2].
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Vasilakos, Konstantinos. "Lick the Toad: a web-based interface for collective sonification." In Simpósio Brasileiro de Computação Musical. Sociedade Brasileira de Computação - SBC, 2021. http://dx.doi.org/10.5753/sbcm.2021.19444.
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Lick the Toad is an ongoing project developed as a web based interface that runs in modern browsers. It provides a custom made platform to collect user data accessed from mobile devices, such as smartphones, tablets etc. The system offers a tool for interactive collective sonification aiding the idea of networked music performance. It can be used in various contexts, such as onsite installation, interactive compositional tool, or for the distribution of raw data for live coding performances. The system embeds neural network capabilities for prediction purposes by using user input and outputs/targets alike. The inputs and the targets of the training processes can be adapted according to the needs of the use making it a versatile component for creative practice. It is developed as open-source project and it works currently as a NodeJS application with plans for future deployment on remote server to support remote communication and interaction amongst distant users.
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Vogt, William, Alondra Izquierdo-Roman, and Christopher G. Rylander. "Tissue Optical Clearing Devices: Effects of Water Content on the Hyperelastic Mechanical Properties of Ex Vivo Porcine Skin." In ASME 2010 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2010. http://dx.doi.org/10.1115/sbc2010-19478.
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Skin is a highly anisotropic and heterogeneous material composed of water, proteins, and various cells arranged in several different layers. Because of this complex structure, there is a large mismatch in index of refraction between the tissue constituents, creating a highly scattering medium for near-infrared and visible light. “Tissue optical clearing” methods can improve light transmission through tissues, potentially improving optical imaging techniques and photoirradiative treatments [1]. Dehydration has been suggested as a possible mechanism of optical clearing [2], and previous work has demonstrated mechanical loading as a method of creating reversible localized water displacement in skin using novel tissue optical clearing devices (TOCDs) [3–4]. These TOCDs were hypothesized to increase light transmission by displacing water locally in the tissue, causing local dehydration. A model of the mechanical behavior of skin will enable improvement of current TOCDs that utilize local mechanical compression.
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Fellows, Ryan, Hisham Ihshaish, Steve Battle, Ciaran Haines, Peter Mayhew, and J. Ignacio Deza. "Task-Oriented Dialogue Systems: Performance vs Quality-Optima, A Review." In 12th International Conference on Computer Science and Information Technology (CCSIT 2022). Academy and Industry Research Collaboration Center (AIRCC), 2022. http://dx.doi.org/10.5121/csit.2022.121306.
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Task-oriented dialogue systems (TODS) – designed to assist users to achieve a goal – are continuing to rise in popularity as various industries find ways to effectively harness their capabilities, saving both time and money. However, even state-of-the-art TODS have not yet reached their full potential. TODS typically have a primary design focus on completing the task at hand, so the metric of task-resolution should take priority. Other conversational quality attributes that may point to the success, or otherwise, of the dialogue, are usually ignored. This can harm the interactions between the human and the dialogue system leaving the user dissatisfied or frustrated. This paper explores the role of conversational quality attributes within dialogue systems, looking at if, how, and where they are utilised, and examining their correlation with the performance of the dialogue system.
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Blow, K. J., R. J. Manning, and A. J. Poustie. "Nonlinear Optical Loop Mirrors with Feedback and a Slow Nonlinearity." In Nonlinear Guided Waves and Their Applications. Washington, D.C.: Optica Publishing Group, 1996. http://dx.doi.org/10.1364/nlgw.1996.saa.2.
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The fibre-based nonlinear optical loop mirror (NOLM)[1] has been one of the most successful devices for demonstrating a range of all-optical processing functions. Recently, the SLALOM [2] or TOAD [3] configuration has been developed where a semiconductor optical amplifier (SOA) is used as the nonlinear material in a fibre loop, rather than the fibre itself. The lack of full recovery in the amplifier causes an interaction between adjacent pulses in the input pulse stream which, for example, can lead to patterning effects in data demultiplexing [4]. This pulse interaction combined with optical feedback leads to an enhancement of the dynamics on timescales much shorter than the feedback time. In this work involving the TOAD/SLALOM with feedback, we have observed spontaneous clock division as a result of the non-zero response times of the SOA.
Reports on the topic "Cane toads"
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Dong, Hongwei. Can Californian Households Save Money on Transportation Costs by Living in Transit-Oriented Developments (TODs)? Mineta Transportation Institute, January 2022. http://dx.doi.org/10.31979/mti.2022.2012.
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Many residents in large Californian metropolitan areas are heavily burdened by housing costs. Advocates, researchers, and elected officials in California are debating whether transit-oriented development (TOD) could be an effective tool to mitigate the housing affordability problem by increasing housing supply and reducing transportation costs in transit-rich neighborhoods. This study contributes to this debate by estimating how much Californian families can save on transportation costs by living in transit-oriented developments (TODs). By utilizing the confidential version of the 2010–2012 California Household Travel Survey, this study evaluates the impact of TOD on household transportation expenditures by comparing TOD households with two control groups. When controlling for household demographics, TOD households save $1,232 per year on transportation expenditures—18% of their total annual transportation expenditures. When controlling for both demographics and neighborhood environment, TOD households save $429 per year—about 6% of their total annual transportation expenditures. The study confirms that Californian households save money on transportation costs by living in TODs mainly because they own fewer vehicles. About two-thirds of the savings can be attributed to transit-friendly neighborhood environment and one-third to access to rail transit, which highlights the importance of integrating a rail transit system with supportive land use planning and neighborhood design.
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Bozek, Michael, and Tani Hubbard. Greater Yellowstone Network amphibian monitoring protocol science review: A summary of reviewers’ responses. National Park Service, June 2022. http://dx.doi.org/10.36967/nrr-2293614.
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Science reviews are an essential cornerstone of all excellent science programs and are a requirement of monitoring programs within the Inventory and Monitoring Division of the National Park Service (NPS). Science reviews provide necessary professional critique of objectives, study design, data collection, analysis, scientific interpretation, and how effectively information is transferred to target audiences. Additionally, reviews can help identify opportunities to cooperate more effectively with interested and vested partners to expand the impacts of collective findings across larger landscapes. In December 2020, seven biologists from USGS, USFWS, and NPS provided a critical review of the Greater Yellowstone Network Amphibian Monitoring Protocol for monitoring Columbia spotted frogs (Rana luteiventris), boreal chorus frogs (Pseudacris maculata), western toads (Anaxyrus boreas), western tiger salamanders (Ambystoma mavortium), and environmental conditions at wetland sites clustered within watershed units in Yellowstone and Grand Teton national parks. This review followed sixteen years of GRYN amphibian and wetland monitoring, allowing us to evaluate the impact of the work thus far and to discuss potential improvements to the protocol. Reviewers were asked to assess the following amphibian monitoring objectives per Bennetts et al. (2013, Cooperative amphibian monitoring protocol for the Greater Yellowstone Network: Narrative, version 1.0, https://irma.nps.gov/DataStore/Reference/Profile/2194571) and to assess the degree to which GRYN is meeting the objectives based on the current sampling, analyses, and reporting: Objective 1: Estimate the proportion of catchments and wetland sites used for breeding by each of the four common, native amphibian species annually, and estimate the rate at which their use is changing over time. Objective 2: Determine the total number of wetlands within sampled catchments that are suitable for amphibian breeding (i.e., have standing water during the breeding season) annually. Objective 3: For western toads, estimate the proportion of previously identified breeding areas that are used annually, and estimate the rate at which their use may be changing over time. Generally, reviewers commended the GRYN Amphibian Monitoring Program, including the design, the statistical rigor of current analytical approaches, the large number of monitoring reports and publications, and the audiences reached. Reviewers unanimously felt that the first two objectives of this protocol are being met for two species (Columbia spotted frogs and boreal chorus frogs) in medium- and high-quality catchments, and all but one reviewer also felt these objectives are being met for western tiger salamanders. It was universally recognized that objective 3 for western toads is not being met but reviewers attributed this to issues related to funding and capacity rather than design flaws. Reviewers felt the current design provides an adequate base for parlaying additional work and offered suggestions focused on increasing efficiencies, maximizing information that can be collected in the field, strengthening analyses, and improving scientific outreach. In this document, we summarize reviewers' comments and include their full written reviews in Appendix B.
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Fachinelli, Ana Cristina, Cíntia Paese Giacomello, Bianca Libardi, Catiane Borsatto, Rafael de Lucena Perini, Suane de Atayde Moschen, and Suélen Bebber. Perfil socioeconômico de Caxias do Sul 2021. UCS - Universidade de Caxias do Sul, June 2022. http://dx.doi.org/10.18226/9786500465075.
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Ao produzir este perfil socioeconômico, analisamos a estrutura social e econômica de Caxias do Sul. Destacamos em todo o material as qualidades de Caxias do Sul, apresentando-o como um ambiente favorável para viver com qualidade de vida e desenvolver negócios. Esta publicação consolida diversas informações sobre Caxias do Sul e serve como referência para apoiar decisões de investimento, formulação de políticas, informar os visitantes e o público sobre os ativos e passivos do município, e seus fatos socioeconômicos. A revista Perfil Socioeconômico de Caxias do Sul tem como objetivo apresentar à comunidade os aspectos que mais se destacam na cidade. Os eixos temáticos foram definidos e, com base neles, são apresentados os dados primários obtidos de fontes oficiais. Séries históricas e comparações com dados estatais e nacionais nos permitem posicionar Caxias do Sul em relação a outros lugares. A responsabilidade pela coleta e análise dos dados cabe à equipe da Citylivinglab, um grupo de pesquisa do Programa de Pós-Graduação em Administração da Universidade de Caxias do Sul. A publicação é baseada em dados secundários, e todas as fontes são citadas em toda a revista. Sempre utilizamos os dados mais recentes disponíveis.
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Freiría, Heber, Alejandro Nin Pratt, and Gonzalo Muñoz. Productividad y eficiencia en la producción ganadera pastoril en América Latina: Los casos de Bolivia y Colombia. Inter-American Development Bank, March 2021. http://dx.doi.org/10.18235/0003150.
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El estudio examina el desempeño de la producción ganadera en Bolivia y Colombia. Se trata de dos ganaderías con diferente trayectoria, madurez tecnológica, y desempeño productivo, y que tienen en común la existencia de “frontera agrícola”, es decir, cambios de uso del suelo que permiten incorporar tierras de pastoreo a la ganadería, a partir de bosques. En el caso de Bolivia, el estudio se limitó a la región oriental, compuesta por los departamentos de Beni y Santa Cruz, que concentra la mayor parte del inventario ganadero del país. Beni, el departamento tradicionalmente ganadero, muestra estancamiento en el período, en lo que respecta al inventario ganadero y la productividad. No han existido inversiones ni cambio técnico importantes en materia de alimentación y manejo del ganado. En Santa Cruz se ha producido un incremento importante de la producción en la primera mitad del período, con aumentos de productividad basados en el cambio técnico. Este cambio técnico se asocia a la implantación de pasturas, a partir de cambios en el uso del suelo. El crecimiento observado en Santa Cruz, en la primera mitad del período (hasta 2012) se detiene a partir de ese año, y la productividad de los factores decrece, dando como resultado un aumento de productividad casi nulo en el total del período analizado. El cambio técnico operado, basado en un modelo de cambio de uso del suelo con siembra de pastos, en competencia por la tierra con soja y otros cultivos, mostró su potencial de generar crecimiento, pero no fue capaz de sostenerlo. La ganadería colombiana muestra un importante incremento de producción en el período analizado. Puesto que los factores de producción (básicamente tierra e inventario ganadero), se incrementan en menor proporción, se verifica un considerable incremento en la productividad de los factores. Existe heterogeneidad en el desempeño entre rubros y regiones. La ganadería de leche es muy importante en Colombia, y predomina en regiones de trópico alto, relativamente maduras en tecnología. Al analizar la evolución de la productividad de los factores, sin embargo, la tasa de crecimiento es mayor en las regiones en que predomina la ganadería de carne. Incluso se verifica cierta sustitución entre rubros, con avance de la producción de carne en todas las regiones. El crecimiento se asocia a mejoras en nutrición del ganado, por siembra de pastos, y en menor medida suministro de suplementos. El diferente comportamiento de los rubros se refleja en su diferente capacidad de competir ante la producción importada, en la medida que la protección se reduce en el marco de los acuerdos comerciales suscritos por el país. La producción ganadera pastoril tiene a su vez implicancias ambientales Los análisis realizados en este estudio, muestran que una variable determinante de la intensidad de emisiones es la productividad de los factores. Debido a esto, la ganadería colombiana presenta menores intensidades de emisión, y con reducción a tasas mayores que las del oriente boliviano. Otro aspecto decisivo en el balance de GEI está dado por los cambios en uso del suelo asociados a la ganadería. Si la producción ganadera que reemplaza bosques no lo hace con alta productividad, el balance resultante afectará en mayor medida el desempeño ambiental de la ganadería de los países.