COMPUTER SIMULATIONS OF POSSIBLE FUTURES FOR TWO FLOCKS OF WHOOPING CRANES

We conducted computer simulations using the program VORTEX (version 7) to project population sizes, growth rates, genetic diversity, and probabilities of extinction over the next 100 years for 2 flocks of whooping cranes (Grus americana), the Aransas/Wood Buffalo population and the experimental Florida population. Standard runs based on best estimates of demographic. genetic, and environmental parameter values were used as a baseline to which several alternative scenarios were compared. Results generally supported the conclusion of the earlier Population Viability Assessment (Mirande et al. 1991) that the AransaslWood Buffalo population will continue to grow steadily with less than a 1 % probability of extinction. It was noted, however, that a combination of negative factors such as shrinking habitat and increased probabilities of catastrophes accompanied by increased mortality rates could put this population at risk. Results for the Florida population were less optimistic. The standard run produced a population growth rate (r) of only 0.0026 for the next 100 years, and this shifted down to -0.0001 over a 200-year time frame. Adult mortality in this flock would have to be about 20% lower than the predicted value (10%) in order to raise growth rates to above r = 0.02. Amount and duration of supplementation of the Florida flock had minimal impacts on the long-tenn growth rate of the flock. It is the enduring rates of mortality, breeding, and disease risk that will have major effects on this population. For example, if disease risks tum out to be greater than the best-estimate scenario, this population could face a relatively high risk of extinction (17%). The formula for success in Florida is lower adult mortality, lower age of first breeding, lower disease risk, and higher productivity than the best-guess estimates. Fortunately, there are some potential management interventions (e.g., predator control, vaccines and health monitoring, selective introductions to balance the sex ratio of the flock) that may be able to push the odds in favor of success

Testing a global standard for quantifying species recovery and assessing conservation impact.

Recognizing the imperative to evaluate species recovery and conservation impact, in 2012 the International Union for Conservation of Nature (IUCN) called for development of a "Green List of Species" (now the IUCN Green Status of Species). A draft Green Status framework for assessing species' progress toward recovery, published in 2018, proposed 2 separate but interlinked components: a standardized method (i.e., measurement against benchmarks of species' viability, functionality, and preimpact distribution) to determine current species recovery status (herein species recovery score) and application of that method to estimate past and potential future impacts of conservation based on 4 metrics (conservation legacy, conservation dependence, conservation gain, and recovery potential). We tested the framework with 181 species representing diverse taxa, life histories, biomes, and IUCN Red List categories (extinction risk). Based on the observed distribution of species' recovery scores, we propose the following species recovery categories: fully recovered, slightly depleted, moderately depleted, largely depleted, critically depleted, extinct in the wild, and indeterminate. Fifty-nine percent of tested species were considered largely or critically depleted. Although there was a negative relationship between extinction risk and species recovery score, variation was considerable. Some species in lower risk categories were assessed as farther from recovery than those at higher risk. This emphasizes that species recovery is conceptually different from extinction risk and reinforces the utility of the IUCN Green Status of Species to more fully understand species conservation status. Although extinction risk did not predict conservation legacy, conservation dependence, or conservation gain, it was positively correlated with recovery potential. Only 1.7% of tested species were categorized as zero across all 4 of these conservation impact metrics, indicating that conservation has, or will, play a role in improving or maintaining species status for the vast majority of these species. Based on our results, we devised an updated assessment framework that introduces the option of using a dynamic baseline to assess future impacts of conservation over the short term to avoid misleading results which were generated in a small number of cases, and redefines short term as 10 years to better align with conservation planning. These changes are reflected in the IUCN Green Status of Species Standard

THE EFFECT OF DISTURBANCE ON THE REPRODUCTION AND MANAGEMENT OF CAPTIVE CRANES

A retrospective analysis of egg laying histories and observations of crane pairs at the International Crane Foundation and the Patuxent Wildlife Research Center indicates that disturbance associated with captivity has adverse impacts on captive breeding. Females on public display laid significantly fewer eggs than those off display (P \u3c 0.05). Crane pairs moved to other pens (other than adjacent pens) or hetween facilities laid slightly fewer eggs than those birds which were not moved. although the results were not statistically significant (P = 0.188). Pen design and construction also appeared to have adverse impacts on breeding. In addition, human activities, intraspecific interactions, and rearing methods influence a bird\u27s response to disturbance, and, therefore, these factors must also be considered in an effective crane management program. Modifying procedures to minimize disturbance, timing necessary disturbances after the breeding and molt seasons, and carefully monitoring birds for signs of stress can result in increased reproductive potential for captive, endangered cranes

Cranes: Their Biology, Husbandry, and Conservation

The Patuxent Wildlife Research Center has placed online this entire (1996) textbook entitled Cranes: Their Biology, Husbandry, and Conservation. Edited by David Ellis, George Gee, and Claire Mirande, the textbook contains thirteen chapters by the world's leading crane experts, covering general biology, husbandry, behavior, artificial insemination, pest management, and conservation, among other topics. In addition to the text, numerous illustrations capture the majesty of these birds. Chapters may be downloaded separately, or browsed online. For anyone interested in cranes and their conservation, this resource is definitely required reading