Whooping crane demographic responses to winter drought focus conservation strategies

AbstractFocusing conservation strategies requires identifying the demographic parameters and environmental conditions affecting the growth of animal populations most. Therefore, we examined relationships between population demographics and winter drought (1950–2011) for endangered whooping cranes (Grus americana) wintering in Texas, USA. We modeled winter loss and its contribution to annual mortality as functions of winter drought, determined recruitment needed to maintain population growth after drought, and identified which demographic parameters underpin this population’s growth. Previous research assumed winter loss (i.e., birds missed in subsequent surveys) represented mortality. We show that loss includes temporary emigration to upland habitats, early migration, and incomplete detection. Despite this, we maintained this assumption to evaluate the relevance of winter mortality to population growth. We found that winter loss (β^=-0.308, SE=0.042) and its contribution to annual mortality (β^=-0.318, SE=0.047) increased with drought severity (Palmer hydrological drought index; PHDI). Given average recruitment (0.145, SD=0.090), this population increases 1.2% (95% CI=−2.9% to 4.2%) after extreme drought (PHDI=−4). No recruitment must occur for 3years with moderate to severe drought (PHDI<−2.5) to delay species’ recovery ≈7years. This scenario has not occurred since population monitoring began in 1938. Of the demographic parameters we examined, winter loss explained population growth least (14.4%; 95% CI=3.6–35.8%), and it was partially compensatory. Breeding–migratory mortality explained 42.2% (95% CI=19.1–61.5%) of population growth and recruitment 49.9% (95% CI=20.6–75.2%). Our results focus conservation on breeding and migratory periods, and deemphasize winter mortality and drought. On the wintering grounds, conservation of whooping cranes should emphasize maintaining coastal, upland, and interior habitats for this population

WHOOPING CRANE STAY LENGTH IN RELATION TO STOPOVER SITE CHARACTERISTICS

Whooping crane (Grus americana) migratory stopovers can vary in length from hours to more than a month. Stopover sites provide food resources and safety essential for the completion of migration. Factors such as weather, climate, demographics of migrating groups, and physiological condition of migrants influence migratory movements of cranes (Gruidae) to varying degrees. However, little research has examined the relationship between habitat characteristics and stopover stay length in cranes. Site quality may relate to stay length with longer stays that allow individuals to improve body condition, or with shorter stays because of increased foraging efficiency. We examined this question by using habitat data collected at 605 use locations from 449 stopover sites throughout the United States Great Plains visited by 58 whooping cranes from the Aransas–Wood Buffalo Population tracked with platform transmitting terminals. Research staff compiled land cover (e.g., hectares of corn; landscape level) and habitat metric (e.g., maximum water depth; site level) data for day use and evening roost locations via site visits and geospatial mapping. We used Random Forest regression analyses to estimate importance of covariates for predicting stopover stay length. Site-level variables explained 9% of variation in stay length, whereas landscape-level variables explained 43%. Stay length increased with latitude and the proportion of land cover as open-water slough with emergent vegetation as well as alfalfa, whereas stay length decreased as open-water lacustrine wetland land cover increased. At the site level, stopover duration increased with wetted width at riverine sites but decreased with wetted width at palustrine and lacustrine wetland sites. Stopover duration increased with mean distance to visual obstruction as well as where management had reduced the height of vegetation through natural (e.g., grazing) or mechanical (e.g., harvesting) means and decreased with maximum water depth. Our results suggest that stopover length increases with the availability of preferred land cover types for foraging. High quality stopover sites with abundant forage resources may help whooping cranes maintain fat reserves important to their annual life cycle

Comprehensive analysis of dose intensity of acute lymphoblastic leukemia chemotherapy

Chemotherapy dosages are often compromised, but most reports lack data on dosages that are actually delivered. In two consecutive acute lymphoblastic leukemia trials that differed in their asparaginase formulation, native E. coli L-asparaginase in St. Jude Total 15 (T15, n=365) and pegaspargase in Total 16 (T16, n=524), we tallied the dose intensities for all drugs on the low-risk or standard-risk arms, analyzing 504,039 dosing records. The median dose intensity for each drug ranged from 61-100%. Dose intensities for several drugs were more than 10% higher on T15 than on T16: cyclophosphamide (P<0.0001 for the standard- risk arm), cytarabine (P<0.0001 for the standard-risk arm), and mercaptopurine (P<0.0001 for the low-risk arm and P<0.0001 for the standardrisk arm). We attributed the lower dosages on T16 to the higher asparaginase dosages on T16 than on T15 (P<0.0001 for both the low-risk and standard-risk arms), with higher dose-intensity for mercaptopurine in those with anti-asparaginase antibodies than in those without (P=5.62x10-3 for T15 standard risk and P=1.43x10-4 for T16 standard risk). Neutrophil count did not differ between protocols for low-risk patients (P=0.18) and was actually lower for standard-risk patients on T16 than on T15 (P<0.0001) despite lower dosages of most drugs on T16. Patients with low asparaginase dose intensity had higher methotrexate dose intensity with no impact on prognosis. The only dose intensity measure predicting a higher risk of relapse on both studies was higher mercaptopurine dose intensity, but this did not reach statistical significance (P=0.03 T15; P=0.07 T16). In these intensive multiagent trials, higher dosages of asparaginase compromised the dosing of other drugs for acute lymphoblastic leukemia, particularly mercaptopurine, but lower chemotherapy dose intensity was not associated with relapse

A Disease-Mediated Trophic Cascade in the Serengeti and its Implications for Ecosystem C

The removal of rinderpest had cascading effects on herbivore populations, fire, tree density, and even ecosystem carbon in the Serengeti ecosystem of East Africa

New genetic loci link adipose and insulin biology to body fat distribution.

Body fat distribution is a heritable trait and a well-established predictor of adverse metabolic outcomes, independent of overall adiposity. To increase our understanding of the genetic basis of body fat distribution and its molecular links to cardiometabolic traits, here we conduct genome-wide association meta-analyses of traits related to waist and hip circumferences in up to 224,459 individuals. We identify 49 loci (33 new) associated with waist-to-hip ratio adjusted for body mass index (BMI), and an additional 19 loci newly associated with related waist and hip circumference measures (P < 5 × 10(-8)). In total, 20 of the 49 waist-to-hip ratio adjusted for BMI loci show significant sexual dimorphism, 19 of which display a stronger effect in women. The identified loci were enriched for genes expressed in adipose tissue and for putative regulatory elements in adipocytes. Pathway analyses implicated adipogenesis, angiogenesis, transcriptional regulation and insulin resistance as processes affecting fat distribution, providing insight into potential pathophysiological mechanisms

Range expansion of the globally Vulnerable Karamoja apalis Apalis karamojae in the Serengeti ecosystem

This study was funded by the Rufford Maurice Laing Foundation, the Canadian Natural Sciences and Engineering Research Council and Frankfurt Zoological Society.The underlying causes of change in geographic range size are less well understood in African birds than in north temperate species. Here, we examine factors associated with range expansion in the Karamoja apalis (Apalis karamojae), a globally Vulnerable warbler confined to north-east Uganda, north-central Tanzania and southern Kenya. In Tanzania, it was originally known only from the Wembere Steppe, but since 1993 (and possibly as early as 1983) has extended its range into the Serengeti ecosystem, c. 140 km to the north, reaching southern Kenya by 2004. Changes in the warbler's range within the Serengeti have broadly reflected a cyclical change in the density of its main habitat, Acacia drepanolobium woodland, which was low in the 1970s, high during the 1980s and 1990s, and declined in the early 2000s. Karamoja apalis records in the Serengeti showed a 5 year time lag behind A. drepanolobium density, which was in turn negatively correlated with the area of grassland burnt 10 years earlier. Previous studies in the Serengeti have also linked Acacia regeneration to changes in grazing pressure, as increasing wildebeest (Connochaetes taurinus) numbers have reduced the volume of combustible material present, and hence the frequency of damaging 'hot burns'. We conclude that this globally threatened warbler appears to have benefited from changes in ungulate populations in the Serengeti, which have influenced burning intensity and hence tree regeneration. The warbler's range now appears to be declining, however, following a recent reduction in the density and annual survival of A. drepanolobium in the northern Serengeti.Resume Les causes sous-jacentes du changement de la taille d'une distribution geographique sont moins bien connues pour les oiseaux africains que pour les especes du nord tempere. Nous examinons ici des facteurs lies a l'expansion de l'aire de repartition de l'apalis de Karamoja Apalis karamojae, un sylviide classe comme Vulnerable au niveau mondial, confine au NE de l'Ouganda, au centre-nord de la Tanzanie et au sud du Kenya. En Tanzanie, on ne le connaissait a l'origine que dans la steppe de Wembere mais depuis 1993, et peut-etre meme des 1983, il a etendu son aire de repartition dans l'ecosysteme du Serengeti, environ 140 km plus au nord, et atteint le sud du Kenya en 2004. Les changements de l'aire de repartition de ce sylviide dans le Serengeti refletent largement un changement cyclique de la densite de son habitat principal, la foret d'Acacia drepanolobium, qui etait faible dans les annees 1970, forte pendant les annees 1980 et 1990, et qui a diminue au debut des annees 2000. Les rapports sur l'apalis de Karamoja au Serengeti montrent un retard de cinq ans par rapport a l'evolution de la densite d'A. drepanolobium, elle-meme etant negativement liee a la zone de prairie brulee 10 ans plus tot. Des etudes anterieures faites au Serengeti lient aussi la regeneration des acacias aux changements de la pression du paturage, etant donne que le nombre croissant de gnous, Connochaetes taurinus, a reduit le volume des matieres combustibles restantes et donc la frequence des feux trop chauds qui causent beaucoup de degats. Nous concluons que cet oiseau menace au niveau mondial semble avoir beneficie des changements des populations d'ongules au Serengeti, qui ont influence l'intensite des feux et donc la regeneration des arbres. L'aire de repartition de ce sylviide semble pourtant en train de se reduire suite a une recente reduction de la densite et de la survie annuelle d'A. drepanolobium dans le nord du Serengeti.PostprintPeer reviewe

Predicting impacts of sea level rise on wintering redhead ducks along the lower Texas Coast

The potential impacts of sea level rise to wildlife populations and their habitats are of concern. Localized relative sea levels have been rising at elevated rates compared to global sea levels, and this trend will impact coastal plant communities, particularly wetlands. The Laguna Madre, a hypersaline lagoon, is home to nearly 80% of North America's redheads (Aythya americana) during winter. The large, shallow lagoon provides optimal growing conditions for seagrasses, including shoalgrass (Halodule wrightii), the redhead's primary winter food. Adjacent to the Laguna Madre are coastal ponds, on which redheads rely for fresh water. The close proximity of these freshwater sources to the coast makes them vulnerable to saltwater intrusion due to sea level rise. Using Sea Level Affecting Marshes Model (SLAMM), we modeled the impacts of sea level rise on coastal ponds and foraging areas along the lower Texas coast through the year 2100. We also determined which coastal habitat types would be most affected by rising sea levels. The SLAMM model indicated that 9 land cover types had a ≥50% change in occurrence from the initial 1999 time period to 2100. The model also predicted that 93 of the known 156 coastal ponds would become inundated with salt water. The predicted loss of foraging habitat and its typical proximity to coastal ponds creates a need to identify where conservation and enhancement of wintering redhead habitat should be placed to mitigate the effects of sea level rise. Keywords: Laguna madre, Redhead, Sea level affecting marshes model, Sea level ris

Diurnal habitat selection of migrating Whooping Crane in the Great Plains

Available stopover habitats with quality foraging opportunities are essential for migrating waterbirds, including Whooping Crane (Grus americana). Several studies have evaluated habitats used by Whooping Crane for roosting throughout its migration corridor; however, habitats associated with foraging and other diurnal activities have received less attention. We used data collected from 42 Whooping Crane individuals that included 2169 diurnal use locations within 395 stopover sites evaluated during spring 2013 to fall 2015 to assess diurnal habitat selection throughout the U.S. portion of the migration corridor. We found that Whooping Crane selected wetland land-cover types (i.e., open water, riverine, and semipermanent wetlands) and lowland grasslands for diurnal activities over all other land-cover types that we evaluated, including croplands. Whooping Crane generally avoided roads, and avoidance varied based on land-cover class. There has been considerable alteration and destruction of natural wetlands and rivers that serve as roosting and foraging sites for migrating Whooping Crane. Given recent droughts and the likelihood of future landscape changes within the migration corridor, directing conservation efforts toward protecting and enhancing wetland stopover areas may prove critical for continued growth of the last remaining wild population of Whooping Crane. Future studies of this Whooping Crane population should focus on specific wetland complexes and riverine sites throughout the migration corridor to identify precise management actions that could be taken to enhance and protect these imperilled land-cover types

Range expansion of the globally Vulnerable Karamoja apalis Apalis karamojae in the Serengeti ecosystem

The underlying causes of change in geographic range size are less well understood in African birds than in north temperate species. Here, we examine factors associated with range expansion in the Karamoja apalis (Apalis karamojae), a globally Vulnerable warbler confined to north-east Uganda, north-central Tanzania and southern Kenya. In Tanzania, it was originally known only from the Wembere Steppe, but since 1993 (and possibly as early as 1983) has extended its range into the Serengeti ecosystem, c. 140 km to the north, reaching southern Kenya by 2004. Changes in the warbler's range within the Serengeti have broadly reflected a cyclical change in the density of its main habitat, Acacia drepanolobium woodland, which was low in the 1970s, high during the 1980s and 1990s, and declined in the early 2000s. Karamoja apalis records in the Serengeti showed a 5 year time lag behind A. drepanolobium density, which was in turn negatively correlated with the area of grassland burnt 10 years earlier. Previous studies in the Serengeti have also linked Acacia regeneration to changes in grazing pressure, as increasing wildebeest (Connochaetes taurinus) numbers have reduced the volume of combustible material present, and hence the frequency of damaging 'hot burns'. We conclude that this globally threatened warbler appears to have benefited from changes in ungulate populations in the Serengeti, which have influenced burning intensity and hence tree regeneration. The warbler's range now appears to be declining, however, following a recent reduction in the density and annual survival of A. drepanolobium in the northern Serengeti.ResumeLes causes sous-jacentes du changement de la taille d'une distribution geographique sont moins bien connues pour les oiseaux africains que pour les especes du nord tempere. Nous examinons ici des facteurs lies a l'expansion de l'aire de repartition de l'apalis de Karamoja Apalis karamojae, un sylviide classe comme Vulnerable au niveau mondial, confine au NE de l'Ouganda, au centre-nord de la Tanzanie et au sud du Kenya. En Tanzanie, on ne le connaissait a l'origine que dans la steppe de Wembere mais depuis 1993, et peut-etre meme des 1983, il a etendu son aire de repartition dans l'ecosysteme du Serengeti, environ 140 km plus au nord, et atteint le sud du Kenya en 2004. Les changements de l'aire de repartition de ce sylviide dans le Serengeti refletent largement un changement cyclique de la densite de son habitat principal, la foret d'Acacia drepanolobium, qui etait faible dans les annees 1970, forte pendant les annees 1980 et 1990, et qui a diminue au debut des annees 2000. Les rapports sur l'apalis de Karamoja au Serengeti montrent un retard de cinq ans par rapport a l'evolution de la densite d'A. drepanolobium, elle-meme etant negativement liee a la zone de prairie brulee 10 ans plus tot. Des etudes anterieures faites au Serengeti lient aussi la regeneration des acacias aux changements de la pression du paturage, etant donne que le nombre croissant de gnous, Connochaetes taurinus, a reduit le volume des matieres combustibles restantes et donc la frequence des feux trop chauds qui causent beaucoup de degats. Nous concluons que cet oiseau menace au niveau mondial semble avoir beneficie des changements des populations d'ongules au Serengeti, qui ont influence l'intensite des feux et donc la regeneration des arbres. L'aire de repartition de ce sylviide semble pourtant en train de se reduire suite a une recente reduction de la densite et de la survie annuelle d'A. drepanolobium dans le nord du Serengeti.</p