The reproductive ecology of Tubastraea coccinea Lesson, an azooxanthellate tropical scleractinian coral, was studied over various periods from 1985 to 2006 at four principal eastern PaciWc locations in Costa Rica, Panamá, and the Galápagos Islands (Ecuador). This small (polyp diameter 0.8-1.0 cm), relatively cryptic species produced ova and planulae year round, including colonies with as few as 2-10 polyps. Of 424 colonies examined histologically, 13.7% contained both ova and sperm. Mature ova varied in diameter from »300 to 800 m and the time from spawning and fertilization of oocytes to release of brooded planulae was about 6 weeks. Planulae were 0.5-1.5 mm long and they settled and metamorphosed on a variety of substrates after 1-3 days. Spermaries, though more diYcult to distinguish in histological sections, were present throughout the year. Spent spermaries were never observed in sections, but several colonies in Panamá and the Galápagos Islands released sperm from night one to night Wve after full moon, indicating the potential for cross-fertilization among colonies. Planula release was observed at Uva Island (Panamá) in March, May, June, and July, and in general planula presence was higher at warm ocean temperatures at all sites, whether or not the sites were inXuenced by seasonal upwelling. Annual fecundity estimates for T. coccinea are comparable with other high fecundity brooding species, including the zooxanthellate Porites panamensis, with which it co-occurs in Panamá. Tubastraea coccinea is widely distributed in the tropical Indo-PaciWc and has colonized substrates in the western Atlantic. In addition to the reproductive characteristics described in the present study, other features of the biology of T. coccinea, such as an ability to withstand conditions that produce bleaching and mortality in zooxanthellate species, may account for its widespread, low-latitude distribution in multiple oceans.
Decisions affecting wildlife management and conservation policy of imperiled species are often aided by population models. Reliable population models require accurate estimates of vital rates and an understanding of how vital rates vary geographically. The eastern massasauga (Sistrurus catenatus catenatus) is a rattlesnake species found in the Great Lakes region of North America. Populations of the eastern massasauga are fragmented and only a few areas harbor multiple, sizable populations. Eastern massasauga research has typically focused on single populations or local metapopulations but results suggest that demographic parameters vary geographically. We used 21 radiotelemetry datasets comprising 499 telemetered snakes from 16 distinct locations throughout the range of the eastern massasauga to characterize geographic patterns of adult survival using the known‐fate model in Program MARK. Annual adult survival ranged from 0.35 to 0.95 (mean = 0.67) and increased along a southwest to northeast geographic axis. Further analysis of 6 datasets indicated no consistent difference in survival between males and females. Our results provide a better understanding of the relationship between survivorship and geography for the eastern massasauga and suggest that such variation should be incorporated into population models as well as local and regional management plans. © 2012 The Wildlife Society.
Humans have long provided nest boxes in a widespread and popular effort to augment nesting sites for cavity‐nesting birds. Nest boxes, however, may provide easy access for predators and thereby create ecological traps for nesting birds. Predator exclusion techniques are often deployed at nest boxes to reduce nest predation, but few studies have tested their performance. For the first time, we test the effectiveness of predator guards in promoting the nesting success of multiple species of birds at a large spatial scale (United States and Canada). We used nest fate data from 24,114 nest records submitted from 2014 to 2016 to NestWatch, a citizen‐science program focused on quantifying nesting success, to determine whether installing predator guards on nest boxes is an effective management technique. Across all species, top models predicting daily nest survival rates suggest a positive influence of predator guards, with a nearly 7% increase in nest success for attempts in boxes with guards versus attempts in boxes without guards. At the species level, nest survival was greater for individuals nesting in boxes with guards in 7 of 9 species, with no effect in the remaining 2 species. Although all types of guards were correlated with improved nesting success, birds nesting in boxes with cone‐type baffles, stovepipe baffles, or entrance hole extenders were most likely to result in successful nesting. Further, birds nesting in boxes with multiple predator guards were more successful, on average, than birds nesting in boxes with only a single guard. Our results can help managers of cavity‐nesting birds incorporate science‐based evidence into decision‐making and allocate resources more effectively. © 2017 The Wildlife Society.
Elucidating how life history traits vary geographically is important to understanding variation in population dynamics. Because many aspects of ectotherm life history are climate-dependent, geographic variation in climate is expected to have a large impact on population dynamics through effects on annual survival, body size, growth rate, age at first reproduction, size–fecundity relationship, and reproductive frequency. The Eastern Massasauga (Sistrurus catenatus) is a small, imperiled North American rattlesnake with a distribution centered on the Great Lakes region, where lake effects strongly influence local conditions. To address Eastern Massasauga life history data gaps, we compiled data from 47 study sites representing 38 counties across the range. We used multimodel inference and general linear models with geographic coordinates and annual climate normals as explanatory variables to clarify patterns of variation in life history traits. We found strong evidence for geographic variation in six of nine life history variables. Adult female snout-vent length and neonate mass increased with increasing mean annual precipitation. Litter size decreased with increasing mean temperature, and the size–fecundity relationship and growth prior to first hibernation both increased with increasing latitude. The proportion of gravid females also increased with increasing latitude, but this relationship may be the result of geographically varying detection bias. Our results provide insights into ectotherm life history variation and fill critical data gaps, which will inform Eastern Massasauga conservation efforts by improving biological realism for models of population viability and climate change.
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