Spatial consistency in drivers of population dynamics of a declining migratory bird.

Many migratory species are in decline across their geographical ranges. Single-population studies can provide important insights into drivers at a local scale, but effective conservation requires multi-population perspectives. This is challenging because relevant data are often hard to consolidate, and state-of-the-art analytical tools are typically tailored to specific datasets. We capitalized on a recent data harmonization initiative (SPI-Birds) and linked it to a generalized modelling framework to identify the demographic and environmental drivers of large-scale population decline in migratory pied flycatchers (Ficedula hypoleuca) breeding across Britain. We implemented a generalized integrated population model (IPM) to estimate age-specific vital rates, including their dependency on environmental conditions, and total and breeding population size of pied flycatchers using long-term (34-64 years) monitoring data from seven locations representative of the British breeding range. We then quantified the relative contributions of different vital rates and population structure to changes in short- and long-term population growth rate using transient life table response experiments (LTREs). Substantial covariation in population sizes across breeding locations suggested that change was the result of large-scale drivers. This was supported by LTRE analyses, which attributed past changes in short-term population growth rates and long-term population trends primarily to variation in annual survival and dispersal dynamics, which largely act during migration and/or nonbreeding season. Contributions of variation in local reproductive parameters were small in comparison, despite sensitivity to local temperature and rainfall within the breeding period. We show that both short- and long-term population changes of British breeding pied flycatchers are likely linked to factors acting during migration and in nonbreeding areas, where future research should be prioritized. We illustrate the potential of multi-population analyses for informing management at (inter)national scales and highlight the importance of data standardization, generalized and accessible analytical tools, and reproducible workflows to achieve them.

Transplantation of Descemet's membrane carrying viable endothelium through a small scleral incision.

PURPOSE: To design a technique for transplantation of the Descemet's membrane (DM) as a carrier for its endothelium, while maintaining the low-astigmatic recipient anterior corneal curvature. METHODS: In a human eye bank eye model, recipient eyes (n = 15) had a 5.0-mm scleral tunnel incision made, extending 1.0 mm into the peripheral cornea. A 9.0-mm-diameter Descemeto rhexis was created, i.e., a circular portion of DM was stripped from the posterior stroma. With use of a custom-made inserter, a 9.0-mm-diameter donor DM carrying autologous donor endothelium was brought into the anterior chamber and positioned against the recipient posterior stroma. The procedure was evaluated by keratometry, endothelial vital and supravital staining, and light microscopy. RESULTS: Mean postoperative astigmatism was 1.0 D (+/-0.6 D). Implanted donor DM showed an intact endothelial cell layer, with 3.4% (+/-1.1%) dispersed focal cell death. Microscopy showed normal endothelial cell morphology and complete apposition of the donor DM against the recipient posterior stroma. CONCLUSIONS: DM can be transplanted in vitro with acceptable damage to the donor endothelium and with little induced astigmatism.

Sutureless, posterior lamellar keratoplasty: a case report of a modified technique.

PURPOSE: To describe a technique for sutureless, posterior lamellar keratoplasty. METHODS: The procedure was performed for a case of pseudophakic bullous keratopathy. Through a 5.0-mm, self-sealing scleral tunnel incision, a stromal pocket was dissected across the cornea, just above Descemet's membrane. An 8.5-mm diameter posterior lamellar disc, consisting of posterior stroma, Descemet's membrane, and endothelium, was transplanted without suture fixation. RESULTS: One week after surgery, the best spectacle corrected visual acuity (BSCVA) was 0.8 (20/25), with S -1.5 and C -1.0 x 85 degrees. After 1 year, the posterior transplant was clear and in position, and the BSCVA was 0.8 with S -1.5 and C -1.75 x 80 degrees. Pachymetry measured 0.60 mm. Endothelial cell counts averaged 1390 cells/mm2. CONCLUSION: Sutureless, posterior lamellar keratoplasty may be an effective new surgical approach for managing corneal endothelial disorders.