Search

Chelonians are expected to be negatively impacted by climate change due to limited vagility and temperature-dependent sex determination. However, few studies have examined how freshwater turtle distributions may shift under different climate change scenarios. We used a maximum entropy approach to model the distribution of five widespread North American Kinosternon species ( K. baurii, K. flavescens, K. hirtipes, K. sonoriense, and K. subrubrum) under four climate change scenarios. We found that areas with suitable climatic conditions for K. baurii and K. hirtipes are expected to decline substantially during the 21st century. In contrast, the area with suitable climate for K. sonoriense will remain essentially unchanged, while areas suitable for K. flavescens and K. subrubrum are expected to substantially increase. The centroid for the distribution of four of the five species shifted northward, while the centroid for K. sonoriense shifted slightly southward. Overall, centroids shifted at a median rate of 37.5 km per decade across all scenarios. Given the limited dispersal ability of turtles, it appears unlikely that range shifts will occur rapidly enough to keep pace with climate change during the 21st century. The ability of chelonians to modify behavioral and physiological responses in response to unfavorable conditions may allow turtles to persist for a time in areas that have become increasingly unsuitable, but this plasticity will likely only delay local extinctions. [ABSTRACT FROM AUTHOR]

Yellow rails ( Coturnicops noveboracensis) winter along the U.S. coast, from North Carolina to Texas and southeastern Oklahoma. Although this rail is listed as a species of special concern in most of the provinces and states where it breeds, little is known about the winter ecology or population sizes of this secretive species. The goals of our study were to approximate numbers and determine age and sex ratios of yellow rails wintering in selected marshes at San Bernard National Wildlife Refuge (San Bernard NWR) in Brazoria and Matagorda counties, Texas. Yellow rails were banded in Spartina marshes from November 2009-April 2010. Feather samples were collected from each yellow rail for use in DNA sexing. We captured 170 yellow rails at the Cedar Lake Creek Unit of San Bernard NWR and recaptured 17 rails over the course of the study. We estimated that the population in marshes we sampled at San Bernard NWR (224.6 ha) from late November through mid-April consisted of 1,170 ± 300 individuals, or 5.2 ± 1.3 rails/ha. The highest ranked POPAN models suggest that the probability of recapture and the probability of entering the population were both time-dependent, while the probability of survival was time-independent. All yellow rails captured prior to January ( n = 17) could be aged, with six (35.2%) aged as HY (Hatch Year), while 11 (64.7%) were aged as AHY (After Hatch Year). However, we were unable to conclusively assign ages to rails captured in January through April. Sufficient DNA was obtained from 59 yellow rails to determine that 33 (55.9%) were male. While the winter range of this species is widespread, it is likely that the coastal prairies of Texas are particularly important for this species given the large numbers and high density of rails encountered during this study. [ABSTRACT FROM AUTHOR]

Recent studies have shown that, in response to global climate change, diverse avian taxa are now nesting measurably earlier (< 10 days) in both the United States and Britain. Similarly, several studies on European birds have now demonstrated that a variety of species (although not all) are arriving increasingly early. However, surprisingly, widespread changes in North American migrant phenology have not been demonstrated. It is hypothesized that short-distance migrants (birds that winter in the southern United States) may be quicker to adapt to climate change than long-distance migrants (birds that winter south of the United States), as short-distance migrants can respond to meteorological cues indicating weather conditions to the north whereas long-distance migrants must rely on photoperiod. This study examined the first arrival dates of 103 migrant birds in New York and Massachusetts and found that, on average, all migrants arrived significantly earlier during the period 1951–1993 than the period 1903–1950. From 1951–1993 birds wintering in the southern United States arrived on average 13 days earlier while birds wintering in South America arrived 4 days earlier. Although a change in observer effort cannot be quantified and may be a source of bias, a comparison of the numbers of reporting observers during the 1930s and the 1980s revealed no significant difference. These results are consistent with those expected under a scenario of global warming. [ABSTRACT FROM AUTHOR]