Desert amphibian selection of arid land breeding habitat undermines reproductive effort (original) (raw)
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Physiology and Ecology to Inform Climate Adaptation Strategies for Desert Amphibians
2016
Many amphibian populations in desert environments are likely at risk of decline or extirpation due to more extreme weather driven by climate change. Most desert species are explosive breeders, taking advantage of rainfall large enough to potentially support reproduction. Hence, management strategies for amphibians in general may not apply to anurans in temperate and subtropical deserts. Sustaining populations of desert amphibians is complex in that we are managing species assemblages that are relatively vulnerable to climate change, while planning for an environment that will change in ways that are not clear. However, we can improve the success of proactive management by integrating physiology with ecology within the context of a changing climate. Explicit consideration of physiology and ecology can target efficient habitat management actions such as identifying where to add shading or to extend hydroperiod. This approach can also improve outcomes when re-establishing native fauna by identifying life stages robust to release. Further we can improve our management of invasive species by explicit consideration of physiological constraints on dispersal capability of the invasive species to help plan where to fragment habitat connectivity to block invasions. To effectively plan for desert amphibians and climate change, science, management and policy makers must openly communicate about what we know, what information we lack, and the limitations of our knowledge. By explicitly including physiology in our management decisions we can refine our approach and more efficiently apply limited resources of time and money.
Ecological and genetic variation of the distribution of various species of amphibians
The current mini-review describes the distribution of amphibian species in terms of their adaptation from Mediterranean to desert climates. According to the data collected in this mini-review and from some unpublished data, it was found that the adaptation of amphibian species from arid to Mediterranean climates was highest for Bufovariabilis, followed by Triturusvittatus,Hylasavignyi, Pelobatessyriacus, Rana bedriagae and Latonia nigriventer. Many parameters affecting adaptation to different habitats have been described, including aquatic and terrestrial habitats. Among them, the most important parameters affecting semi-arid and arid habitats are the large number of tadpoles, the short growth and complete metamorphosis period, finding hiding places to prevent dehydration, and physiological adaptation to accumulate urea in the body fluid. A quality model is suggested to show the adaptation of various amphibian species to habitats at the southern border of its distribution.
Canadian Journal of Zoology
Worldwide amphibian declines highlight the need for programs that monitor species presence and track population trends. We sampled larval amphibians with a box trap at 3-week intervals for 23 months in eight wetlands, and concurrently trapped adults and juveniles with drift fences, to examine spatiotemporal patterns of tadpole occurrence; explore relationships between breeding effort, tadpole abundance, and recruitment; and compare the efficacy of both methods in detecting species presence and reproductive outcome. Intermittent detection of species within and among wetlands suggested high mortality, followed by deposition of new eggs and tadpole cohorts. Breeding effort, tadpole abundance, and juvenile recruitment were generally not correlated. The reasons for this may include differential bias in detecting species or life stages between methods and high incidence of egg or tadpole mortality. Drift fences detected more species than box traps, but each provided insights regarding amp...
The current mini-review describes the distribution of amphibian species in terms of their adaptation from Mediterranean to desert climates. According to the data collected in this mini-review and from some unpublished data, it was found that the adaptation of amphibian species from arid to Mediterranean climates was highest for Bufovariabilis, followed by Triturusvittatus,Hylasavignyi, Pelobatessyriacus, Rana bedriagae and Latonia nigriventer. Many parameters affecting adaptation to different habitats have been described, including aquatic and terrestrial habitats. Among them, the most important parameters affecting semi-arid and arid habitats are the large number of tadpoles, the short growth and complete metamorphosis period, finding hiding places to prevent dehydration, and physiological adaptation to accumulate urea in the body fluid. A quality model is suggested to show the adaptation of various amphibian species to habitats at the southern border of its distribution.
Amphibian Breeding and Climate Change
Conservation Biology, 2001
Climate changes may be influencing the breeding patterns of certain organisms. Effects on breeding activities could eventually lead to significant changes in population structure that may be reflected in population declines of species that are especially sensitive, such as some amphibians. Thus, climate changes may have affected the timing of breeding in some European amphibian species. To further test whether amphibian reproductive cycles in temperate countries are responding to climate changes, we conducted an analysis of the breeding phenology of four species of North American anurans for which we have long-term data sets. Populations of at least two of these species have been declining, and it has been suggested that they and other amphibians may be especially sensitive to climate change. Our results suggest that climate change has not influenced the timing of breeding in amphibians in North America. At one site, in Oregon, a trend (nonsignificant) for western toads ( Bufo boreas ) to breed increasingly early was associated with increasing temperature. At four other sites, however, neither western toads nor Cascades frogs ( Rana cascadae ) showed statistically significant positive trends toward earlier breeding. At three of four of these sites, breeding time was associated with warmer temperatures. The spring peeper ( Pseudacris crucifer ) in Michigan did not show a statistically significant trend toward breeding earlier but did show a significant positive relationship between breeding time and temperature. Fowler's toad ( Bufo fowleri ) in eastern Canada did not show a trend toward breeding earlier, and there was no positive relationship between breeding time and temperature. It did however, show a strong but statistically insignificant trend toward breeding later. The broad pattern emerging from available studies is that some temperate-zone anuran populations show a trend toward breeding earlier, whereas others do not. It is important to track the breeding patterns of amphibians with long-term data sets to more fully understand how we can manage threatened populations.
Breeding phenology of an amphibian community in a Mediterranean area
Amphibia-reptilia, 2006
We studied the temporal breeding patterns and strategies of anuran assemblages in the Mediterranean region over five consecutive years. We collected monthly data on the number of clutches, tadpoles and juveniles presence of six species in 98 ponds. The data showed a great temporal segregation of species. Species using permanent ponds have a breeding peak that is related to temperature whereas reproductive success in temporary pond breeders is determined by rainfall pulses. Many species showed great plasticity of reproduction with two peaks: one in spring and the other in autumn. In spite of this temporal segregation, a large overlap was observed among species during the larval phase period. Three species (Alytes obstetricans, Pelodytes punctatus and Rana perezi) have over-wintering tadpoles. We discuss temporal segregation, differences between species in their breeding strategies and variable conditions between years as factors that favour the temporal coexistence of species in the Mediterranean region.