Browsing by Author "Beja, Pedro"
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- Assessing bird exclusion effects in a wetland crossed by a railway (Sado estuary, Portugal)Publication . Godinho, Carlos; Catarino, Luísa; Marques, João T.; Mira, António; Beja, PedroLinear transportation infrastructures may displace wildlife from nearby areas that otherwise would provide adequate habitat conditions. This exclusion effect has been documented in roads, but much less is known about railways. Here we evaluated the potential exclusion effect on birds of a railway crossing a wetland of international importance (Sado Estuary, Portugal). We selected 22 sectors representative of locally available wetland habitats (salt pans, rice paddy fields, and intertidal mudflats); of each, half were located either close to (0–500 m) or far from (500–1500 m) the railway line. Water birds were counted in each sector between December 2012 and October 2015, during two months per season (spring, summer, winter, and autumn) and year, at both low and high tide. We recorded 46 species, of which the most abundant (>70% of individuals) were black-headed gull, greater flamingo, northern shoveler, black-tailed godwit, and lesser black-backed gull. Peak abundances were found in autumn and winter. There was no significant variation between sectors close to and far from the railway in species richness, total abundance, and abundance of the most common species. Some species tended to be most abundant either close to or far from the railway albeit not significantly so but this often varied across the tidal and annual cycles. Overall, our study did not find noticeable exclusion effects of this railway on wetland birds, with spatial variation in abundances probably reflecting habitat selection and daily movement patterns. Information is needed on other study systems to assess the generality of our findings
- At the tipping point: Can biodiversity and rural livelihoods endure uncontrolled cashew expansion in West Africa?Publication . Guedes, Patrícia; Palmeirim, Ana Filipa; Monteiro, Filipa; Catarino, Luís; Palma, Luís; Temudo, Marina P.; Henriques, Mohamed; Beja, Pedro; Lopes, Ricardo Jorge; Ladle, Richard J.; Powell, Luke L.Our commentary explores the increase in cashew cultivation across West Africa, drawing attention to its impacts on biodiversity and livelihoods. We summarize the issue regionally, then showcase Guinea-Bissau, where we unravel the dynamics between cashew expansion, habitat and biodiversity loss, and livelihoods. Finally, we propose concrete policy measures encompassing strengthened conservation, sustainable land-use planning, enhanced farming practices, community engagement, and international market reforms. Our recommendations extend beyond both a recent review (Rege et al. 2023) and a concise policy commentary on EU deforestation law (Powell et al. 2023) in offering a roadmap for sustainable cashew cultivation.
- Biodiversity conservation: history, protected areas and hotspotsPublication . Huntley, B.J.; Beja, Pedro; Pinto, Pedro Vaz; Russo, Vladimir; Veríssimo, Luís; Morais, MiguelAngola is a large country of great physiographic, climatic and habitat diversity, with a corresponding richness in animal and plant species. Legally protected areas (National Parks and Game Reserves) were established from the 1930s and occupied 6% of the country’s terrestrial area at the time of independence in 1975. As a consequence of an extended war, the Protected Areas were exposed to serious neglect, poaching and land invasions. Many habitats of biogeographic importance, and many rare and endemic species came under threat. The recently strengthened administration gives cause for optimism that a new era for biodiversity conservation is at hand. The Protected Areas system was greatly expanded in 2011, and increasing resources are being made available towards achieving management effectiveness
- Biodiversity monitoring in Europe: user and policy needsPublication . Moersberger, Hannah; Valdez, Jose; Martin, Juliette G. C.; Junker, Jessica; Georgieva, Ivelina; Bauer, Silke; Beja, Pedro; Breeze, Tom D.; Fernandez, Miguel; Fernández, Néstor; Brotons, Lluís; Jandt, Ute; Bruelheide, Helge; Kissling, W. Daniel; Langer, Christian; Liquete, Camino; Lumbierres, Maria; Solheim, Anne Lyche; Maes, Joachim; Morán‐Ordóñez, Alejandra; Moreira, Francisco; Pe'er, Guy; Santana, Joana; Shamoun‐Baranes, Judy; Smets, Bruno; Capinha, César; McCallum, Ian; Pereira, Henrique M.; Bonn, AlettaTo achieve the goals of the 2030 Global Biodiversity Framework, the EuropeanBiodiversity Strategy, and the EU Green Deal, biodiversity monitoring is critical.Monitoring efforts in Europe, however, suffer from gaps and biases in taxon-omy, spatial coverage, and temporal resolution, resulting in fragmented anddisconnected data. To assess user and policy needs in biodiversity monitoring,we employed a four-step user-centered stakeholder engagement process withover 300 stakeholders including a public stakeholder workshop, online survey,interviews, and a meeting with experts from 18 EU member states, the EuropeanCommission, and the European Environment Agency. The stakeholders identi-fied policy needs, current challenges, and potential solutions. Based on the policyand stakeholder assessment, we recommend establishing a European Biodiver-sity Observation Coordinating Centre to optimize existing observation efforts,harmonize data, and enhance our ability to predict and respond to key challengesrelated to biodiversity loss in Europe.
- Bird collisions in a railway crossing a wetland of international importance (Sado estuary, Portugal)Publication . Godinho, Carlos; Marques, João T.; Salgueiro, Pedro; Catarino, Luísa; Castro, Cândida Osório de; Mira, António; Beja, PedroMany studies have evaluated bird mortality in relation to roads and other human structures, but little is known about the potential impacts of railways. In particular, it is uncertain whether railways are an important mortality source when crossing wetlands heavily used by aquatic birds. Here we analyze bird collisions in a railway that crosses the Nature Reserve of the Sado Estuary (Portugal) over an annual cycle, documenting bird mortality and the flight behaviour of aquatic birds in relation to a bowstring bridge. During monthly surveys conducted on 16.3 km of railway, we found 5.8 dead birds/km/10 survey days in the section crossing wetland habitats (6.3 km), while <0.5 dead birds/km/10 survey days were found in two sections crossing only forested habitats. Most birds recorded were small songbirds (Passeriformes), while there was only a small number of aquatic birds (common moorhen, mallard, flamingo, great cormorant, gulls) and other non-passerines associated with wetlands (white stork). During nearly 400 h of observations, we recorded 27,000 movements of aquatic birds across the Sado bridge, particularly in autumn and winter. However, only <1% of movements were within the area of collision risk with trains, while about 91% were above the collision risk area, and 8% were below the bridge. Overall, our case study suggests that bird collisions may be far more numerous in railways crossing wetland habitats than elsewhere, although the risk to aquatic birds may be relatively low. Information from additional study systems would be required to evaluate whether our conclusions apply to other wetlands and railway lines
- Calandra lark habitat selection: strong fragmentation effects in a grassland specialistPublication . Morgado, Rui; Beja, Pedro; Reino, Luís; Gordinho, Luís; Delgado, Ana; Borralho, Rui; Moreira, FranciscoConserving grassland birds in farmed landscapes requires the maintenance of favourable agricultural land uses over a range of spatial and temporal scales. Here we examined the field and landscape-scale habitat requirements of the calandra lark (Melanocorypha calandra), an obligate grassland bird often associated with open Mediterranean farmland. Breeding and wintering lark densities were assessed in 42 fallowfields in southern Portugal, and related to three sets of variables reflecting field, landscape and neighbourhood effects. Variation partitioning was used to isolate the unique and shared contributions of sets of variables to explained variation in lark distribution and abundance models. At the field scale, the presence of trees and shrubs showed the strongest negative effects on calandra lark. At the landscape scale therewere strong positive response of larks to the amount and patch size of open farmland habitats, and negative responses, albeit weaker, to drainage and road densities. Calandra lark distribution and abundance was also positively related to that of conspecifics in surrounding fields, particularly in spring. Results suggest that calandra larks are highly sensitive to habitat fragmentation, requiring fallow fields with no shrubs or trees, embedded in large expanses of open farmland. This supports the view that grassland bird conservation in Mediterranean agricultural landscapes may require a combination of land-use regulations and agri-environment schemes preventing ongoing shrub encroachment and afforestation of marginal farmland.
- Canopy arthropod declines along a gradient of olive farming intensificationPublication . Vasconcelos, Sasha; Pina, Silvia; Herrera, José M.; Silva, Bruno; Sousa, Pedro; Porto, Miguel; Melguizo-Ruiz, Nereida; Jimenez-Navarro, Gerardo; Ferreira, Sónia; Moreira, Francisco; Heleno, Ruben; Jonsson, Mattias; Beja, PedroArthropod declines have been linked to agricultural intensification. However, information about the impacts of intensification is still limited for many crops, as is our understanding of the responses of different arthropod taxa and trophic groups, thus hindering the development of effective mitigation measures. We investigated the impacts of olive farming intensification on canopydwelling arthropods in the Mediterranean region. Intensification involves the increased use of agrochemicals, mechanisation and irrigation, but also structural changes from traditional orchards with low densities of large and old trees, to intensive and superintensive orchards with high to very high densities of smaller and younger trees, respectively. Canopy arthropods were vacuumsampled at 53 sites representing the three orchard intensification levels, in spring, summer and autumn 2017. We evaluated how the arthropod community varied across intensification levels, and in response to orchard structure, management and landscape context. We found no changes in the diversity of arthropod taxa across intensification levels after correcting for sample coverage, but arthropod abundance declined markedly along the intensification gradient. Decreased abundance was associated with changes in orchard structure, lower herbaceous cover, and higher herbicide and insecticide use. The abundance of a specialized olive pest was lower in landscapes with higher woodland cover. The negative effects of intensification were stronger in spring and summer than in autumn, and parasitoids and predators were particularly affected. Overall, results suggest that retaining herbaceous cover, reducing agrochemical inputs and preserving natural woody elements in the landscape, may contribute to mitigate impacts of olive farming intensification on canopy arthropods, particularly on beneficial species
- Combined effects of landscape composition and heterogeneity on farmland avian diversityPublication . Santana, Joana; Reino, Luís; Stoate, Chris; Moreira, Francisco; Ribeiro, Paulo F.; Santos, José L.; Rotenberry, John T.; Beja, PedroConserving biodiversity on farmland is an essential element of worldwide efforts for reversing the global biodiversity decline. Common approaches involve improving the natural component of the landscape by increasing the amount of natural and seminatural habitats (e.g., hedgerows, woodlots, and ponds) or improving the production component of the landscape by increasing the amount of biodiversity-friendly crops. Because these approaches may negatively impact on economic output, it was suggested that an alternative might be to enhance the diversity (compositional heterogeneity) or the spatial complexity (configurational heterogeneity) of land cover types, without necessarily changing composition. Here, we develop a case study to evaluate these ideas, examining whether managing landscape composition or heterogeneity, or both, would be required to achieve conservation benefits on avian diversity in open Mediterranean farmland. We surveyed birds in farmland landscapes of southern Portugal, before (1995–1997) and after (2010–2012) the European Union’s Common Agricultural Policy (CAP) reform of 2003, and related spatial and temporal variation in bird species richness to variables describing the composition, and the compositional and configurational heterogeneity, of the natural and production components of the landscape. We found that the composition of the production component had the strongest effects on avian diversity, with a particularly marked effect on the richness of farmland and steppe bird species. Composition of the natural component was also influential, mainly affecting the richness of woodland/shrubland species. Although there were some effects of compositional and configurational heterogeneity, these were much weaker and inconsistent than those of landscape composition. Overall, we suggest that conservation efforts in our area should focus primarily on the composition of the production component, by striving to maximize the prevalence of biodiversity-friendly crops. This recommendation probably applies to other areas such as ours, where a range of species of conservation concern is strongly associated with crop habitats
- Combining geostatistical and biotic interaction modelling to predict amphibian refuges under crayfish invasion across dendritic stream networksPublication . Mota-Ferreira, Mário; Beja, PedroAim: Biological invasions are pervasive in freshwater ecosystems, often causing native species to contract into areas that remain largely free from invasive species impacts. Predicting the location of such ecological refuges is challenging, because they are shaped by the habitat requirements of native and invasive species, their biotic interactions, and the spatial and temporal invasion patterns. Here, we investigated the spatial distribution and environmental drivers of refuges from invasion in river systems, by considering biotic interactions in geostatistical models accounting for stream network topology. We focused on Mediterranean amphibians negatively impacted by the invasive crayfishes Procambarus clarkii and Pacifastacus leniusculus. Location: River Sabor, NE Portugal. Methods: We surveyed amphibians at 168 200-m stream stretches in 2015. Geostatistical models were used to relate the probabilities of occurrence of each species to environmental and biotic variables, while controlling for linear (Euclidean) and hydrologic spatial dependencies. Biotic interactions were specified using crayfish probabilities of occurrence extracted from previously developed geostatistical models. Models were used to map the distribution of potential refuges for the most common amphibian species, under current conditions and future scenarios of crayfish expansion. Results: Geostatistical models were produced for eight out of 10 species detected, of which five species were associated with lower stream orders and only one species with higher stream orders. Six species showed negative responses to one or both crayfish species, even after accounting for environmental effects and spatial dependencies. Most amphibian species were found to retain large expanses of potential habitat in stream headwaters, but current refuges will likely contract under plausible scenarios of crayfish expansion. Main conclusions: Incorporating biotic interactions in geostatistical modelling provides a practical and relatively simple approach to predict present and future distributions of refuges from biological invasion in stream networks. Using this approach, our study shows that stream headwaters are key amphibian refuges under invasion by alien crayfish
- Dietary metabarcoding reveals the simplification of bird–pest interaction networks across a gradient of agricultural coverPublication . Silva, Luis P. da; Mata, Vanessa A.; Lopes, Pedro B.; Pinho, Catarina J.; Chaves, Catia; Correia, Edna; Pinto, Joana; Heleno, Ruben H.; Timoteo, Sergio; Beja, PedroAgriculture is vital for supporting human populations, but its intensification often leads to landscape homogenization and a decline in non-provisioning ecosystem services. Ecological intensification and multifunctional landscapes are suggested as nature- based alternatives to intensive agriculture, using ecological processes like natural pest regulation to maximize food production. Birds are recognized for their role in increas- ing crop yields by consuming invertebrate pests in several agroecosystems. However, the understanding of how bird species, their traits and agricultural land cover influ- ence the structure of bird–pest interactions remains limited. We sampled bird–pest interactions monthly for 1 year, at four sites within a multifunctional landscape, fol- lowing a gradient of increasing agricultural land cover. We analysed 2583 droppings of 55 bird species with DNA metabarcoding and detected 225 pest species in 1139 samples of 42 bird species. As expected, bird–pest interactions were highly variable across bird species. Dietary pest richness was lower in the fully agricultural site, while predation frequency remained consistent across the agricultural land cover gradient. Network analysis revealed a reduction in the complexity of bird–pest interactions as agricultural coverage increased. Bird species abundance affected the bird's contribu- tion to the network structure more than any of the bird traits analysed (weight, phe- nology, invertebrate frequency in diet and foraging strata), with more common birds being more important to network structure. Overall, our results show that increasing agricultural land cover increases the homogenization of bird–pest interactions. This shows the importance of maintaining natural patches within agricultural landscapes for biodiversity conservation and enhanced biocontrol.