A 2013 report by Michelle Reynolds (Pacific Island Ecosystems Research Center, U.S. Geological Survey, Hawaii, U.S.A.) and colleagues that considers the likely effects of predicted sea level rise on the breeding seabirds, including ACAP-listed Laysan Abatross Phoebastria immutabilis, of the USA’s French Frigate Shoals in the Northern Pacific is now available on line.

The report’s abstract follows:

Globally, seabirds are vulnerable to anthropogenic threats both at sea and on land. Seabirds typically nest colonially and show strong site fidelity; therefore, conservation strategies could benefit from an understanding of the population dynamics and vulnerability of breeding colonies to climate change.  More than 350 atolls exist across the Pacific Ocean; while they provide nesting habitat for many seabirds, they are also vulnerable to sea-level rise.  We used French Frigate Shoals, the largest atoll in the Hawaiian Archipelago, as a case study to explore seabird colony dynamics and the potential consequences of sea-level rise.  We compiled a unique combination of data sets: historical observations of islands and seabirds, a 30-year time series of population abundance, LiDAR- (light detection and ranging) derived elevations, and satellite imagery.  To model population dynamics for ten species at Tern Island from 1980 to 2009, we used the Gompertz model with parameters for the population growth rate, density dependence, process variation, and observation error.  We used a Bayesian approach to estimate the parameters.  All species increased in a pattern that provided evidence of density dependence.  Density dependence may exacerbate the consequences of sea-level rise on seabirds because species that are already near the carrying capacity of the nesting habitat will be limited more than species that still have space for population growth. Laysan Albatross (Phoebastria immutabilis), Great Frigatebird (Fregata minor), Red-tailed Tropicbird (Phaethon rubricauda), Masked Booby (Sula dactylatra), Gray-backed Tern (Onychoprion lunatus), and White Tern (Gygis alba) are likely already at carrying capacity at Tern Island and therefore are most likely to be negatively impacted by sea-level rise. We project 12% of French Frigate Shoals (excluding La Pesrouse Pinnacle) will be inundated with +1.0 m sea-level rise or 32% with +2.0 m. Gray-backed Terns that nest along the coastal perimeters of islands and shrub-nesting species that are habitat limited are especially vulnerable to sea-level rise.  However, at Tern Island, seawalls and habitat creation may mitigate projected seabird population declines due to habitat loss.  We predict substantial losses in seabird nesting habitat across the low-lying Hawaiian Islands by 2100 and emphasize the need to restore higher elevation seabird colonies.”

A Laysan Albatross flies over the low-lying shore, photograph by James Lloyd

Click here to access a related publication by Michelle Reynolds.

Selected References:

Hatfield, J., Reynolds, M.H., Seavy, N.E. & Krause, C.M. 2012. Population dynamics of Hawaiian seabird colonies vulnerable to sea-level rise. Conservation Biology 26: 667-678.

Reynolds, M.H., Courtot, K.N., Berkowitz, P., Storlazzi, C.D., Moore, J. & Flint, E. 2015.  Will the effects of sea-level rise create ecological traps for Pacific island seabirds?  PloS ONE DOI: 10.1371/journal.pone.0136773.

Reynolds, M.H., Courtot, K.N., Krause, C.M., Seavy, N.E., Hartzell, P. & Hatfield, J.S. 2013 (2016).  Dynamics of seabird colonies vulnerable to sea-level rise at French Frigate Shoals, Hawai`i.  Technical Report HCSU-037.  Hilo: Hawai`i Cooperative Studies Unit.  32 pp

Storlazzi, C.D., Berkowitz, P.,Reynolds, M.H. & Logan, J.B. 2013.  Forecasting the Impact of Storm Waves and Sea-level Rise on Midway Atoll and Laysan Island within the Papahānaumokuākea  Marine National Monument - a Comparison of Passive versus Dynamic Inundation Models.  U.S. Geological Survey Open-File Report 2013-1069.  78 pp.

John Cooper, ACAP Information Officer, 11 March 2016

Meritxell Genovart (Population Ecology Group, IMEDEA (CSIC-UIB), Mallorca, Spain) and colleagues have published in the Journal of Applied Ecology on the effects of fishery practices (longlining and an intended discard ban) on the ACAP-listed and Critically Endangered Balearic Shearwater Puffinus mauretanicus.

Balearic Shearwater at sea

The paper’s summary follows:

“1. World-wide, many seabirds are affected by fisheries in opposing ways: as a source of mortality from bycatch, but also by providing discards as a predictable and abundant food resource.  This applies to the Balearic shearwater Puffinus mauretanicus, the most endangered European seabird, whose time to extinction was estimated at only ~40 years a decade ago.

2. Since the previous assessment, new data and more sophisticated demographic modelling have become available, and new fishing policies from the European Union (Common Fisheries Policy, CFP) will apply, posing different scenarios for the viability of the species.  Thus, there is both an urgent need and an opportunity for a more reliable update of the conservation status of the species.

3. Demographic data were collected between 1985 and 2014 at one of the world’s largest colonies.  Most demographic parameters were estimated using multievent capture–recapture modelling.  Some parameters, such as bycatch rate, immature individual survival and recruitment, were estimated for the first time.  We incorporated estimates into stochastic population models to forecast time to extinction and assess the viability under different management scenarios, accounting for upcoming fishing policies.

4. Adult survival was much lower than expected (0_809, SE: 0_013) and largely influenced by bycatch, which accounted for a minimum of 0_455 (SE: 0_230) of total mortality.  Breeding success was positively correlated with discard availability.  Recruitment started at low rates in 3-year-old birds (0_030, SE: 0_0455), increasing in following age classes and was almost complete at 6 years.  Under the present scenario, we predict a time to extinction of 61 years (95% CI: 55–69).

5. Synthesis and applications.  Population projections suggest that the actual impact of fisheries on Balearic shearwaters is unsustainable and the imminent discard ban under the new Common Fisheries Policy may accelerate the declining trend.  This study demonstrates that reducing the bycatch rates of fisheries is an unavoidable and urgent conservation measure for avoiding the extinction of the species.  We also advise setting up demographic long-term studies, to allow researchers to diagnose, with reliability, the effectiveness of management actions.  These actions will also benefit many other marine top-predator species affected by this anthropogenic impact.”

Reference:

Genovart, M., Arcos, J.M., Alvarez, D., McMinn, M., Meier, R. Wynn, R.B., Guilford, T. & Oro, D. 2016.  Demography of the critically endangered Balearic shearwater: the impact of fisheries and time to extinction.  Journal of Applied Ecology doi: 10.1111/1365-2664.12622.

John Cooper, ACAP Information Officer, 10 March 2016

Jann Gilbert (National Marine Science Centre, Southern Cross University, Coffs Harbour, New South Wales, Australia) and colleagues have published on-line in the open-access journal Marine Ornithology on levels of plastic items in stomachs of stranded Short-tailed Shearwaters Puffinus tenuirostris and other Australian seabirds that subsequently died.  A single Wandering Albatross Diomedea exulans examined contained no plastic.

The paper’s summary follows:

“Plastic pollution is a significant problem in all oceans of the world and accounts for up to 90% of marine debris.  Ingestion of plastic by seabirds and its effects are well documented, particularly in the Northern Hemisphere.  However, fewer data exist for levels of plastic in seabird and coastal bird species in Australian waters or the southwestern Pacific.  In this study, the stomach contents of a variety of seabirds and coastal birds (migratory and resident) were analysed for plastic.  Nine (30%) of the birds sampled contained plastic.  The median mass of plastic per bird was 41.7 mg and median number of pieces was 3.0.  Shearwaters Puffinus spp. had significantly higher plastic mass and number of pieces than other species, and the most common type of plastic was manufactured.  However, industrial pellets also contributed substantially.  Plastics were primarily dark in colour.  No clear indication of the influence of plastic ingestion on body condition could be found, however, internal physical damage and intestinal blockage was noted.  Further assessment of the incidence and the effects of plastic ingestion in seabird and coastal bird species in Australian waters is required.”

Short-tailed Shearwater, photograph by Kirk Zufelt

Reference:

Gilbert, J.M., Reichelt-Brushett, A.J., Bowling, A.C. & Christidis, L. 2016.  Plastic ingestion in marine and coastal bird species of southeastern Australia. Marine Ornithology 44: 21-26.

John Cooper, ACAP Information Officer, 09 March 2016

Stephen Totterman (Empire Vale, New South Wales, Australia) writes on-line in the open-access journal Marine Ornithology on differences in measuring Short-tailed Shearwaters Puffinus tenuirostris as study skins or live specimens

The paper’s summary follows:

“External biometrics have many applications in ornithology, and study skins are a major source of these measurements. However, measurements can be imprecise, and skins tend to shrink when they dry — two problems rarely investigated for petrels (family: Procellariidae). This study examined measurement error and shrinkage for 15 biometrics, using Short-tailed Shearwater Puffinus tenuirostris as the subject species. Random measurement error, defined as the variability of repeated measurements of a particular character taken on the same individual relative to its variability among individuals in a particular group, ranged from 0.3% for head plus bill length in dry specimens to 36% for tarsus width in freshly dead birds. Shrinkage of skin specimens stabilised within 2–5 months after preparation. Average fresh-dry shrinkage ranged from 0.2% for head plus bill to 12% for tarsus height. A new method was used to estimate shrinkage variability among individuals. “Shrinkage variation,” defined as the proportion of unexplained variance (1 – r2) in the correlation between paired fresh and dry measurements of a particular character after correcting for measurement error, ranged from 0% for wing chord to 33% for bill base width. More robust biometrics from this study were measurements of large, inflexible characters with well-defined measurement “landmarks.”

Short-tailed Shearwater, photograph by Mark Carey

Reference:

Totterman, S.L. 2016. Random measurement error and specimen shrinkage in Short-tailed Shearwaters Puffinus tenuirostris. Marine Ornithology 44: 11-20.

John Cooper, ACAP Information Officer, 08 March 2016