Influence of climate and fisheries on the demography of giant petrels

ThesisUnderstanding how populations and communities will respond to global changes is a major focus of modern ecology, and demographic studies are crucial for understanding the dynamic of wild populations and their responses to change. Here, I first conducted an analytically robust literature to demonstrate that seabird mortality in global fisheries (bycatch) tends to be biased by sex and age, mainly related to differential at-sea distributions, underpinning the population level effect bycatch on the most threatened group of birds. Next I performed a comprehensive longitudinal study, to address effects of fisheries, environmental variability and climate oscillation on population dynamics of northern (NGP, Macronectes halli) and southern giant petrel (SGP, M. giganteus) at Bird Island, South Georgia. I showed that annual survival and breeding success of NGP and SGP was influenced mainly by climatic oscillation and oceanographic conditions, including fisheries, and that the responses varied by sex and age. Giant petrels survived and reproduced better in warmer years, contrasting with the negative effects of warmer conditions on a range of marine land-based vertebrates in the same ecosystem. Differential accessibility to food resources during chick-rearing due to allochrony have contributed for the NGP breeding success and delayed reproductive senescence compared to SGP, supporting empirical evidence for role of allochrony on their divergent population trajectories. Finally, the findings in this thesis sheds a new light on how phenological mismatch can influence demographic process and on the role of environmental conditions on reproductive senescence, which are among the poorest understood processes in population ecology.Science Without Borders Program (CNPq/Brazil

A Global Mitigation Hierarchy for Nature Conservation

Efforts to conserve biodiversity comprise a patchwork of international goals, national-level plans, and local interventions that, overall, are failing. We discuss the potential utility of applying the mitigation hierarchy, widely used during economic development activities, to all negative human impacts on biodiversity. Evaluating all biodiversity losses and gains through the mitigation hierarchy could help prioritize consideration of conservation goals and drive the empirical evaluation of conservation investments through the explicit consideration of counterfactual trends and ecosystem dynamics across scales. We explore the challenges in using this framework to achieve global conservation goals, including operationalization and monitoring and compliance, and we discuss solutions and research priorities. The mitigation hierarchy's conceptual power and ability to clarify thinking could provide the step change needed to integrate the multiple elements of conservation goals and interventions in order to achieve successful biodiversity outcomes

Global patterns of sex- and age-specific variation in seabird bycatch

Fisheries bycatch is a major threat to seabird populations, and understanding sex- and age-biases in bycatch rates is important for assessing population-level impacts. We analysed 44 studies to provide the first global assessment of seabird bycatch by sex and age, and used generalised models to investigate the effects of region and fishing method. Bycatch was highly biased by sex (65% of 123 samples) and age (92% of 114 samples), with the majority of samples skewed towards males and adults. Bycatch of adults and males was higher in subpolar regions, whereas there was a tendency for more immatures and females to be killed in subtropical waters. Fishing method influenced sex- and age-ratios only in subpolar regions. Sex- and age-biases are therefore common features of seabird bycatch in global fisheries that appear to be associated largely with differences in at-sea distributions. This unbalanced mortality influences the extent to which populations are impacted by fisheries, which is a key consideration for at-risk species. We recommend that researchers track individuals of different sex and age classes to improve knowledge of their distribution, relative overlap with vessels, and hence susceptibility to bycatch. This information should then be incorporated in ecological risk assessments of effects of fisheries on vulnerable species. Additionally, data on sex, age and provenance of bycaught birds should be collected by fisheries observers in order to identify regions and fleets where bycatch is more likely to result in population-level impacts, and to improve targeting of bycatch mitigation and monitoring of compliance

Ecologia reprodutiva de oito espécies ciconiformes em uma colônia da Lagoa dos Patos

Dissertação(mestrado) - Universidade Federal do Rio Grande, Programa de Pós–Graduação em Oceanografia Biológica, Instituto de Oceanografia, 2010.Foi realizado um estudo da abundancia e da ecologia reprodutiva de oito espécies de Ciconiifomes em uma colônia no estuário da Lagoa dos Patos, localizada na Ilha dos Marinheiros, Rio Grande, RS. Foram realizados censos das aves durante o pôr-do-sol e o início da manhã do dia seguinte, desde agosto de 2008 até outubro de 2009, e censos totais de ninhos em novembro de 2008, e em janeiro de 2009. Foram marcados e monitorados 220 ninhos ativos, a saber, 106 de Egretha thula/Bubulcus ibis, 48 de Platalea ajaja, 25 de Ardea alba, 25 de Nycticorx nycticorax, 11 de Ardea cocoi e cinco de Nyctanassa violacea. Ardea cocoi, foi a única espécie que utilizou a área da colônia como local de repouso e dormitório durante o ano todo, enquanto as demais estiveram presentes na primavera e no verão. Foram estimados 1360 ninhos de B. ibis, 751 de P. ajaja, 443 de E. thula, 178 de A. alba, 178 de N. nycticorax, 20 de E. caerulea, 18 de A. cocoi e 16 de N. violacea. Foi encontrada uma correlação significativa entre a massa corporal média dos adultos e a altura média dos ninhos das diferentes espécies (r = 0,891; p = 0,01). Durante o primeiro pulso reprodutivo, a probabilidade de sucesso dos ninhos (Mayfield) foi de 0,315 para P. ajaja; 0,285 para A. alba; 0,271 para N. nycticorax, e de 0,194 para Egretta spp./B. ibis, essas últimas apresentaram um segundo pulso reprodutivo, durante o qual a probabilidade de sucesso dos ninhos foi de 0,571. A colônia da Ilha dos Marinheiros é o maior sítio reprodutivo de P. ajaja já registrado no Brasil, e a maior colônia de Ciconiifomres já registrada do Sul do país, o que demonstra a importância do estuário da Lagos dos Patos como sítio reprodutivo de aves aquáticas, alertando para a necessidade de se realizarem estudos voltados para procurar, mapear e quantificar as possíveis colônias existentes nessa região.We conducted a study on the breeding ecology and abundance of eight species of Ciconiifoms in a colony in the Patos Lagoon estuary, located on the Marinheiros Island, Rio Grande, RS. Bird censuses were conducted during the sunset and early morning the next day, from August 2008 until October 2009. Were also performed ground counts of total nests in November 2008 and January 2009. Were marked and subsequent monitored 220 active nests (106 Egretha thula/Bubulcus ibis, 48 Platalea ajaja, 25 Ardea alba, 25 Nycticorx nycticorax, 11 Ardea cocoi 11, and five Nyctanassa violacea. Ardea cocoi was the only species that used the area of the colony as a resting site throughout the year, while the others were present only during the breeding season (early spring until late summer). We estimated 1360 nests of B. ibis, 751 P. ajaja, 443 E. thula, 178 A. alba, 178 N. nycticorax, 20 E. caerulea, 18 A. cocoi and 16 N. violacea. We found a significant correlation between average body mass of adults and the mean nests height of the different species (r = 0.891, p = 0.01). During the first breeding pulse, the probability of nests success (Mayfield method) was 0.315 for P. ajaja, 0.285 for A. alba, 0.271 for N. nycticorax, and 0.194 for Egretta spp. / B. ibis. A second breeding pulse was observed for E. thula, B. ibis, and E. caeulea during which the probability of nest success was 0.571. The heronry at Marinheiros Island is the largest breeding site for P. ajaja registered in Brazil and the largest colony of Ciconiifomres ever recorded in the southern Brazil, which demonstrates the importance of the of the Patos Lagoon estuary as a breeding site for waterbirds, attention to the need for further studies in order to searching, mapping and quantify the possible colonies in this region

Abundance, breeding and food of the Little Blue Heron Egretta caerulea (Aves, Ardeidae) in the Patos Lagoon estuary, a recently colonized area in southern Brazil

We document the expansion of the breeding distribution of the Little Blue Heron Egretta caerulea (Linnaeus, 1758) to 850 km beyond its previous southern limit in South America. In addition we present data on abundance, breeding biology and food of the species in the Patos Lagoon estuary, the area which the species recently colonized. The maximum abundance recorded in the breeding colony and in a nocturnal roosting site was 53 and 49 individuals respectively. Nesting occurred from September to March. Birds nested in a mixed breeding colony together with about 3,000 breeding pairs of seven other species of Pelecaniformes, in a swampy forest near the margin of the estuary. Five nests were between 1.5 and 4.3 m from the ground, on the shrub Daphnopsis racemosa (Thymelaeaceae), on the trees Sebastiana brasiliensis (Euphorbiaceae) and Mimosa bimucronata (Leguminosae), or on the bamboo Bambusa sp. (Poaceae). Four nests produced two fledglings each, while one nest was abandoned. Of 13 grouped samples of food regurgitated by five nestlings, Pink Shrimp Farfantepenaeus paulensis (Perez-Farfante, 1967) constituted 70% in mass, while total length of ingested fishes and shrimps varied mostly between 20 and 50 mm. Estuarine prey items represented 99% of the total food mass. The recent southward expansion of the breeding range of the Little Blue Heron in South America may be a response to climate warming of the Patos Lagoon estuary. Degradation of estuaries in the southwestern Atlantic may also be forcing the birds to breed in areas outside previous geographical range

New records, distribution and status of six seabird species in Brazil

Distribution records of poorly-known species are currently the most explored theme in the Brazilian seabird literature. If properly evaluated, this kind of information can improve our knowledge on distribution, migration and status of occurrence of these species. In this note we present new records for six species of poorly-known seabirds in the Brazilian coast, reviewing distribution records and defining their status of occurrence in the country. We consider Chionis albus (Gmelin, 1789) a pseudo-vagrant in Brazil and define its status as a scarce seasonal visitor from southern South America. We present the first records of Leucophaeus atricilla (Linnaeus, 1758) for Trindade Island, and of Leucophaeus pipixcan (Wagler, 1831) for the state of Rio Grande do Sul, and determined that the former is a vagrant in eastern Brazil and the latter a vagrant across the country. Anous stolidus (Linnaeus, 1758) is a vagrant in southernmost Brazil. We were unable to determine if records of Chlidonias niger (Linnaeus, 1758) for Brazil and southern South America refer to vagrancy or pseudo-vagrancy. Additionally, we verified the occurrence of breeding individuals of Anous minutus Boie, 1844 on Martin Vaz Island and confirmed that there is no evidence of breeding on neighboring Trindade Island