Activity budgets of captive Laysan ducklings (Anas laysanensis)

This study examined how diurnal activity budgets, visibility to observer, and distance to parents changed during the day and during three stages of development of captive Laysan ducklings. All behaviors except feeding, swimming, and terrestrial locomotion varied significantly across the stages of development. There was a significant time of day effect for 5 behaviors: stationary, flying, swimming, under female, and lying. A significant interaction between stage and time of day for 4 behaviors, viz., stationary, flying, under female, and out of sight, was also found. Young ducklings followed the female, were under the female, or were out of sight significantly more often than older ducklings. Older ducklings performed maintenance behaviors or boundary walking, or were stationary, flying, social, lying, or lying out of sight significantly more often than younger ducklings. Swimming and flying were most often performed late in the day, and the ducklings were stationary most often in early and late periods of the day. They were also most often under the female during early and late periods of the day. © 1992 Wiley-Liss, Inc.     

Translocation and early post-release demography of endangered Laysan teal

In an attempt to reduce the high extinction risk inherent to small island populations, we translocated wild Laysan teal Anas laysanensis to a portion of its presumed prehistoric range. Most avian translocations lack the strategic post-release monitoring needed to assess early population establishment or failure. Therefore, we monitored the survival and reproduction of all founders, and their first-generation offspring using radio telemetry for 2 years after the first release. Forty-two Laysan teal were sourced directly from the only extant population on Laysan Island and transported 2 days by ship to Midway Atoll. All birds survived the translocation with nutritional and veterinary support, and spent between 4 and 14 days in captivity. Post-release survival of 42 founders was 0.857 (95% CI 0.86–0.99) during 2004–2006 or annualized 0.92 (95% CI 0.83–0.98). Seventeen of 18 founding hens attempted nesting in the first two breeding seasons. Fledgling success was 0.57 (95% CI 0.55–0.60) in 2005 and 0.63 (95% CI 0.62–0.64) in 2006. The effective founding female population ( N _e) was 13. We applied these initial demographic rates to model population growth. The nascent population size increased to >100 after only 2 years post-release ( λ =1.73). If this growth rate continues, the size of the Midway population could surpass the source population before 2010.     

How to deal with ground truthing affected by human‐induced habitat change?: Identifying high‐quality habitats for the Critically Endangered Red Siskin

Species distribution models (SDM) can be valuable for identifying key habitats for conservation management of threatened taxa, but anthropogenic habitat change can undermine SDM accuracy. We used data for the Red Siskin (Spinus cucullatus), a critically endangered bird and ground truthing to examine anthropogenic habitat change as a source of SDM inaccuracy. We aimed to estimate: (1) the Red Siskin's historic distribution in Venezuela; (2) the portion of this historic distribution lost to vegetation degradation; and (3) the location of key habitats or areas with both, a high probability of historic occurrence and a low probability of vegetation degradation. We ground‐truthed 191 locations and used expert opinion as well as landscape characteristics to classify species' habitat suitability as excellent, good, acceptable, or poor. We fit a Random Forest model (RF) and Enhanced Vegetation Index (EVI) time series to evaluate the accuracy and precision of the expert categorization of habitat suitability. We estimated the probability of historic occurrence by fitting a MaxLike model using 88 presence records (1960–2013) and data on forest cover and aridity index. Of the entire study area, 23% (20,696 km²) had a historic probability of Red Siskin occurrence over 0.743. Furthermore, 85% of ground‐truthed locations had substantial reductions in mean EVI, resulting in key habitats totaling just 976 km², in small blocks in the western and central regions. Decline in Area of Occupancy over 15 years was between 40% and 95%, corresponding to an extinction risk category between Vulnerable and Critically Endangered. Relating key habitats with other landscape features revealed significant risks and opportunities for proposed conservation interventions, including the fact that ongoing vegetation degradation could limit the establishment of reintroduced populations in eastern areas, while the conservation of remaining key habitats on private lands could be improved with biodiversity‐friendly agri‐ and silviculture programs.     

Seed germination of Melocactus sergipensis N.P. Taylor & M.V. Meiado,the newest Brazilian cactus destined for extinction

Recently, a new cactus was discovered in an area of the Caatinga, a tropical dry forest of north‐eastern Brazil. Although this discovery is excellent news, Melocactus sergipensis is critically endangered because it is affected by deforestation of native vegetation and chemicals used in the maize crop, next to the holotype locality. The aim of this study was to evaluate the seed germination and seedling survival of the newest Brazilian cactus. All germination treatments were performed at room temperature and white light or continuous darkness. For the evaluation of establishment, 50 seedlings were examined at 30‐day intervals for 5 months. I did not observe seed germination of M. sergipensis in continuous darkness, which shows that the newly discovered species is positive photoblastic. However, a high germinability was observed under white light (80.0 ± 10.8%), indicating that the seeds of the newly discovered species are able to germinate and the light is needed for seed germination. After 5 months, seedling mortality was less than 5%. These results show that the seedlings of the newly discovered cactus can be produced in a glasshouse, providing support for studies on ex situ conservation of a species that could become extinct in the near future.     

八大公山常绿落叶阔叶混交林影响幼苗存活的主要因子分析

幼苗是植物生活史中最脆弱的阶段,对幼苗存活影响因子的分析有助于我们更清楚的了解森林群落的天然更新机制。利用广义线性混合模型（GLMM）对八大公山常绿落叶阔叶混交林中影响幼苗存活的主要生物与非生物因子进行了研究。结果表明：（1）在群落水平上,幼苗存活与生物因子中的同种幼苗密度呈显著负相关,与非生物因子中的冠层开阔度呈显著正相关;（2）从年龄上看,4年生以下龄级的幼苗存活更容易受到同种幼苗密度的影响,与同种幼苗密度呈显著负相关;4年生及其以上的幼苗存活则主要受非生物因子影响;（3）从生活型上看,相对于常绿物种,落叶物种的幼苗存活率更容易受到同种幼苗密度的影响,也与冠层开阔度呈正相关;（4）在物种水平上,生物因子与非生物因子对不同物种幼苗存活率的影响也不相同。其中,宜昌润楠（Machilus ichangensis Rehd.et Wils.）的存活率与冠层开阔度呈正相关;薄叶山矾（Symplocos anomala Brand）幼苗的存活率与同种幼苗密度、异种大树胸高断面积、林冠开阔度、坡向均呈显著负相关,而与异种幼苗密度和海拔呈显著正相关。本研究表明影响幼苗存活的因子是多样的,而且不是随机发生的。在不同水平上影响幼苗存活的因子不同。