Stopover ecology of migrant songbirds at the Ebro delta = Ecologia de parada migratòria de passeriformes al Delta de l'Ebre

[eng] Migration associated with movements between breeding and wintering areas allow animals to maximize fitness in response to seasonal changes in resources (Dingle 2014). Some of the most incredible migrations in the animal world are performed by birds which are possibly one of the best-studied migratory groups. Prior to migration, birds accumulate fat stores that may account for up to 50% of their body mass (Nielsen and Riis 2013) and once these fat stores are depleted after a flight bout they are replenished at stopover sites along the migration route. Migration is a dangerous life stage, which means that migrants have higher probability of perish while migrating than non-migrants. The mortality rates during the migratory period may be at least 15 times higher compared to that in the stationary periods of the annual life cycle (Sillett and Holmes 2002). Moreover, imagine small passerine birds, many of them inexperienced birds, born only some months before the beginning of migration, sometimes weighting just 10g or less, flying by night thousands of kilometres to encounter new kinds of habitats (Mettke-Hofmann and Greenberg 2005), competition for food resources (Moore and Yong 1991), predators (Lindström 1989), and inclement weather (Newton 2007), all while needing to maintain adequate fat reserves to perform their long-distance flight successfully. In fact, migrant bird populations suffer nowadays a sustained decline as shown in analyses of bird population trends across Europe (Sanderson et al., 2006; Vickery et al. 2014), North America (Ballard et al. 2003) and East Asia (MacKinnon et al. 2012). This decline is strongly associated with the accumulative impact of certain human activities such as habitat loss (Aharon-Rotman 2016), hunting (Raine 2016, Clausen et al. 2017) and climate change (Jiao et al. 2016) on the areas used by birds in their migratory routes (Crick 2004), especially on stopover sites (Bairlein 2016). Understanding the quality and availability of highly used stopover sites is vital for migratory bird conservation (Mehlman et al. 2005) and to know where migratory birds stop during their migrations and how the sites function for migrants will provide information for conservation and management of suitable stopover areas and therefore, help in the development of full-life-cycle specific conservation plans. The Iberian Peninsula geographically connects Africa and Western Europe and migrants use it in transit between breeding and wintering grounds during both migration periods (Newton 2008). It becomes an ideal scenario for the study of migratory strategies (Bruderer and Liechti 1999) especially if we consider also Mediterranean wintering birds. This thesis focusses on the significance of the Ebro delta, as the second most important wetland in the Western Mediterranean, for the migration of songbirds and draw an overall picture of the way migrant passerines use the area as a stopover site. Since the Ebro delta is a highly humanized area where several important economic activities take place (e.g. rice production, hunting, fishing and tourism), as well as a very fragile territory due to severe problems of coastal regression and subsidence, the information here gathered aims to help in future conservation plans that should take into account not only breeding species but also wintering and migrating ones, what will give even more importance to this coastal wetland, which we must protect at all costs. Therefore, this thesis work overs the behaviour of both short/medium and long-distance migrants, i.e. Mediterranean wintering and trans-Saharan species, during their stopover at a coastal lagoon in the Ebro delta during both migration seasons (spring and autumn). The tool used to investigate the issues exposed above was a cheap one and available to everyone who asks for it: the ring-recovery data. Bird ringing is long used to study migration processes, and although nowadays more trendy and modern methods are available (e.g. satellite telemetry, geolocation loggers), not all of them are affordable to everyone who wants to use them. If we realize that the EURING Data Bank (EDB) is a unique set of mark–reencounter data on European birds with more than 10 million encounter records and that is at the disposal of the scientific and conservation communities (du Feu et al. 2016) and that ringing is still required as the key technique for facilitating our understanding of migration (Bairlein and Schaub 2009), we can use its potential to evaluate the importance of stopover areas and contribute to their conservation and also of the species that depend on these areas to survive. Of course, the new methods are very useful and sometimes a lot more precise and the combination of these methods with ringing data will improve considerably our knowledge about the migration phenomenon in the future. But while we look for financing to tag our birds with geolocators, let’s start working out the more basic questions

Using CASIMIR-Vegetation model in the context of modeling riparian woods and fish species to support a holistic approach for environmental flows to be used on river management and conservation

The CASiMiR-vegetation model is a software that recreates the physical processes influencing the survival and recruitment of riparian vegetation, based on the relationship between ecologically relevant flow regime components and riparian vegetation metrics that reflect the vegetation’s responses to flow regime change. Working at a flow response guild level, this tool outperforms equivalent models by overriding various restrictions of the conventional modeling approaches. The potential of the CASiMiR-vegetation model is revealed in its application to different case studies during the development of a holistic approach to determine environmental flows in lowland Mediterranean rivers, based on woody riparian vegetation and fish species. Various modeling circumstances are described where CASiMiR-vegetation model was used with the purpose of sustaining the research addressing the thesis objectives. The main findings already accomplished in this research are highlighted to illustrate the outcomes that can be attained from the use of such a model

Synthesis of the knowledge about Gull-billed Tern Gelochelidon nilotica diet in the Mediterranean area

This work analyses diet composition and trophic diversity of the Gull-billed Tern in 11 colonies in the Mediterranean basin based on published papers and original data from the Ebro Delta (NE Spain). Spearman correlation and correspondence analysis were used to assess the relationship between diet characteristics (trophic diversity and composition) and geographic localization of colonies. Insects were predominant in the diet of the Gullbilled Tern in the Ebro Delta (77.6%), as well as for most of the populations studied (mean of 59.4 % by population). Within insects, coleopterans and orthopterans were the most consumed. For the populations preferring aquatic prey (two localities), crustaceans were the most consumed prey. Vertebrates were less abundant in number (median of 8.5 % by population) and within this group, amphibians were predominant. We did not find any similarity in the diet depending on the geographic proximity of the populations nor any relationship between latitude of population and trophic diversity (reciprocal of index of Simpson 1/H). Finally, in the Mediterranean basin the diet of the Gullbilled Tern is basically formed by insects caught in terrestrial habitatsCe travail analyse le régime alimentaire de la Sterne hansel dans 11 colonies localisées en région Méditerranéenne à partir de travaux publiés et de données originales du delta de l’Èbre (NE Espagne). Nous avons utilisé le coefficient de corrélation de Spearman et l’analyse factorielle des correspondances pour déterminer s’il y a des relations entre le régime alimentaire (diversité trophique et composition) et la localisation géographique des colonies. Les insectes constituent la proie prédominante dans le régime alimentaire de la Sterne hansel du delta de l’Èbre (77,6 %) ainsi que dans la plupart des colonies (moyenne de 59,4 % par colonie). Parmi les insectes, les Coléoptères et les Orthoptères sont les plus consommés. Dans les populations où les proies aquatiques abondent (deux colonies), les crustacés sont les proies prédominantes. Les vertébrés sont numériquement peu abondants (médiane 8,5 % par colonie), les amphibiens étant les plus nombreux dans ce groupe. Les colonies les plus proches ne présentent pas une plus grande similarité dans le régime alimentaire et on ne trouve pas de relation entre la latitude des colonies et leur diversité trophique (inverse de l’indice de Simpson 1/H). Finalement, en région Méditerranéenne, le régime alimentaire de la Sterne hansel est constitué principalement d’insectes capturés dans les milieux terrestre

Comparison and Validation of Hydrological E-Flow Methods through Hydrodynamic Modelling

Flow regime determines physical habitat conditions and local biotic configuration. The development of environmental flow guidelines to support the river integrity is becoming a major concern in water resources management. In this study, we analysed two sites located in southern part of Portugal, respectively at Odelouca and Ocreza Rivers, characterised by the Mediterranean climate. Both rivers are almost in pristine condition, not regulated by dams or other diversion construction. This study presents an analysis of the effect on fish habitat suitability by the implementation of different hydrological e-flow methods. To conduct this study we employed certain hydrological e-flow methods recommended by the European Small Hydropower Association (ESHA). River hydrology assessment was based on approximately 30 years of mean daily flow data, provided by the Portuguese Water Information System (SNIRH). The biological data, bathymetry, physical and hydraulic features, and the Habitat Suitability Index for fish species were collected from extensive field works. We followed the Instream Flow Incremental Methodology (IFIM) to assess the flow-habitat relationship taking into account the habitat suitability of different instream flow releases. Initially, we analysed fish habitat suitability based on natural conditions, and we used it as reference condition for other scenarios considering the chosen hydrological e-flow methods. We accomplished the habitat modelling through hydrodynamic analysis by using River-2D model. The same methodology was applied to each scenario by considering as input the e-flows obtained from each of the hydrological method employed in this study. This contribution shows the significance of ecohydrological studies in establishing a foundation for water resources management actions

Importance of considering riparian vegetation requirements for the long-term efficiency of environmental flows in aquatic microhabitats

Environmental flows remain biased toward the traditional biological group of fish species. Consequently, these flows ignore the inter-annual flow variability that rules species with longer lifecycles and therefore disregard the long-term perspective of the riverine ecosystem. We analyzed the importance of considering riparian requirements for the long-term efficiency of environmental flows. For that analysis, we modeled the riparian vegetation development for a decade facing different environmental flows in two case studies. Next, we assessed the corresponding fish habitat availability of three common fish species in each of the resulting riparian landscape scenarios. Modeling results demonstrated that the environmental flows disregarding riparian vegetation requirements promoted riparian degradation, particularly vegetation encroachment. Such circumstance altered the hydraulic characteristics of the river channel where flow depths and velocities underwent local changes of up to 10 cm and 40 cm s1, respectively. Accordingly, after a decade of this flow regime, the available habitat area for the considered fish species experienced modifications of up to 110% when compared to the natural habitat. In turn, environmental flows regarding riparian vegetation requirements were able to maintain riparian vegetation near natural standards, thereby preserving the hydraulic characteristics of the river channel and sustaining the fish habitat close to the natural condition. As a result, fish habitat availability never changed more than 17% from the natural habitatinfo:eu-repo/semantics/publishedVersio

Determinação de um regime de caudais ecológicos a jusante do empreendimento do Alvito. Relatório Final

Estudo realizado pelo Instituto Superior de Agronomia para a ATKINS, no âmbito do Protocolo de Colaboração ATKINS – ISA-ADISA, de 19 de Junho de 2012O estudo que se apresenta tem como objetivo a definição dos regimes de caudais ecológicos para o aproveitamento hidroelétrico do Alvito, localizado no rio Ocreza, e possíveis futuros aproveitamentos hidroelétricos na ribeira de Alvito. Os regimes foram propostos para cada um dos cursos de água referidos, com base na informação recolhida e modelada em locais de estudo representativos dos cursos de água referidos, tendo ainda sido validados por modelações num local de estudo independente localizado a jusante dos anteriores. Os regimes de caudais propostos neste documento apresentam um carácter inovador e único em Portugal, resultando de uma metodologia que considera não só os requisitos de comunidades aquáticas mas também ripárias, suportada pela modelação matemática de ambas as comunidades e conferindo uma maior aproximação holística ao sistema fluvial. A metodologia apresentada proporciona assim um alargamento do espectro de atuação dos caudais ecológicos apresentados atualmente, considerando para além da variação intra-anual do regime hidrológico natural retratada pela fauna piscícola, a sua variação interanual, cuja influência no ecossistema fluvial é espelhada pela vegetação ripária. Nos capítulos que se seguem relatam-se os trabalhos efetuados com vista a produzir os regimes propostos, desde os levantamentos de campo e amostragens biológicas até aos resultados obtidos nas modelações efetuadas. Por fim, o presente relatório culmina na construção dos regimes de caudais ecológicos com planificação decénia, conjugando regimes de caudais mensais com cheias de período de retorno plurianualN/

Aquatic biodiversity and quality of streams in certified eucalypt plantations in central Portugal

Em Portugal, mais de 150.000 ha de plantações de eucalipto (Eucalyptus globulus) são já geridas em conformidade com os sistemas internacionais de certificação. O objetivo deste trabalho foi o de avaliar a biodiversidade e a qualidade ecológica de pequenos rios associados a este tipo de povoamentos, usando diversas comunidades aquáticas – peixes, anfíbios e macroinvertebrados – bem como um índice de condição morfológica fluvial (qualidade do leito e margens). Este estudo foi conduzido em dois cursos de água localizados na zona centro de Portugal, a ribeira da Foz (média dimensão e regime hidrológico permanente) e a ribeira dos Rouxinóis (pequena dimensão e regime intermitente), com envolventes dominadas por plantações certificadas de eucalipto, e por isso com zonas ripícolas bem conservadas. A ribeira da Foz revelou associações piscícolas com elevada riqueza específica e que, embora dominadas por uma espécie exótica (Gobio lozanoi), incluíram várias espécies ameaçadas. A anfíbiofauna apresentou‑se contudo pouco abundante, muito provavelmente devido à grande diversidade e densidade piscícola e à presença significativa do lagostim-vermelho-do-Louisiana (Procambarus clarkii). Neste sistema, registou-se ainda uma boa qualidade da condição morfológica, bem como uma elevada diversidade da comunidade de macroinvertebrados, reflexo de boa qualidade da água. Na ribeira dos Rouxinóis a comunidade piscícola foi próxima da potencial para este tipo de rios, e a anfíbiofauna apresentou-se diversa e abundante. No entanto, a comunidade de macroinvertebrados revelou-se muito pouco diversa, provavelmente devido à menor riqueza de habitats ou às elevadas condutividades aí verificadas. Os resultados demonstraram que rios associados a eucaliptais certificados podem apresentar boa qualidade ecológica e uma significativa biodiversidade aquáticainfo:eu-repo/semantics/publishedVersio

Using CASiMiR-vegetation model to establish riparian vegetation disturbance requirements

The disturbance requirements of riparian vegetation were determined in two Mediterranean rivers based on riparian vegetation modeling. The assessment of the riparian vegetation disturbance requirements were consistent in selecting the best disturbance regime. Such outcome may suggest the probable applicability of this approach to rivers in general and the possibility to preserve artificially the sustainability of the riparian communities in regulated rivers

Atualização do Habitat 91E0* na Rede Natura em Portugal Continental: resultados obtidos no âmbito do projecto LIFE Fluvial

Este documento, relativo à ação A1 do projeto LIFE FLUVIAL, contem a atualização da informação sobre o habitat 91E0* nas áreas pertencentes à Rede Natura 2000 em Portugal Continental. O documento tem o intuito de melhorar o conhecimento sobre a distribuição observada e provável do habitat, incluindo a) uma atualização da presença observada do habitat com base em varias fontes de informação, tais como estudos prévios, trabalhos de cartografia, projetos de investigação e técnicos, registos de herbários, bases de dados florísticas e de vegetação; e b) uma determinação de locais com elevada probabilidade de ocorrência do Habitat 91E0* com base nos modelos desenvolvidos no projeto RIPLANTE nas áreas classificadas na rede natura 2000 em Portugal Continental. A combinação das duas componentes será fundamental para colmatar as lacunas existentes quanto à distribuição deste habitat prioritário e contribuir para a sua conservação no âmbito da Rede Natura 2000.info:eu-repo/semantics/publishedVersio

Agricultural policies against invasive species generate contrasting outcomes for climate change mitigation and biodiversity conservation

Direct consequences of biological invasions on biodiversity and the environment have been largely documented. Yet collateral indirect effects mediated by changes in agri-environmental policies aimed at combating invasions remain little explored. Here we assessed the effects of recent changes in water management in rice farming, which are aimed at buffering the impact of the invasive apple snail (Pomacea maculata, Lamarck) on greenhouse gas emissions and diversity of waterbird communities. We used observational data from a 2-year field monitoring (2015–2016) performed at the Ebro Delta regional scale. We found that drying rice fields reduced methane emission rates by 82% (2015) and 51% (2016), thereby reducing the contribution of rice farming to climate change. However, there was a marked reduction (75% in 2015 and 57% in 2016) in waterbird diversity in dry fields compared with flooded fields, thus suggesting that post-invasion policies might hinder biodiversity conservation. Our results highlight the need for accounting for potential collateral effects during the policy decision-making process to design efficient agricultural management plans that lessen undesirable agri-environmental outcomes.info:eu-repo/semantics/acceptedVersio