Browsing by Author "Morgado, Rui"
Now showing 1 - 10 of 11
Results Per Page
Sort Options
- 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.
- Disentangling the seasonal effects of agricultural intensification on birds and bats in Mediterranean olive grovesPublication . Jiménez-Navarro, Gerardo; Rodríguez-Pérez, Javier; Melguizo-Ruiz, Nereida; Silva, Bruno; Vasconcelos, Sasha; Beja, Pedro; Moreira, Francisco; Morgado, Rui; Barreiro, Silvia; Herrera, José M.Assessing the spatio-temporal impact of agricultural intensification on species and communities is key for biodiversity conservation. Here, we investigated the seasonal effects of olive grove intensification at both local (farming practices and grove structural complexity) and landscape scale (land-cover diversity) on birds and bats, at species and community-level. Both groups were surveyed during spring, summer, and autumn in 60 sites representing varying levels of olive grove intensification throughout the Alentejo region (southern Portugal). At the local scale, the number of chemical applications was used as a proxy for the intensification of farming practices and a Structural Index, which accounted for within-grove variability in tree density and features, was used as a measure of grove structural complexity. At landscape scale, we quantified the proportion of the major land-cover types potentially affecting birds and bats. We found that the abundance of ca. 77% of the species analyzed (ca. 84% and 55% of birds and bats respectively) was negatively related to olive grove intensification in at least one season. The Structural Index was the most influential factor at both species and community-levels, especially for birds, with a consistent and strong effect across seasons. Chemical applications had a stronger negative effect on birds, whereas the amount of olive grove cover had a stronger detrimental effect on bats. Birds and bats showed a variable response to predictor variables depending on the season, particularly for the bat community. Our study shows differences in bird and bat responses associated with the spatio-temporal variability of the agricultural intensification components. On the one hand, birds and bats showed a seasonal pattern of association with the different components of olive grove intensification, probably due to their ecological and biological requirements. On the other hand, the responses of both groups also appear to be scale-dependent: while birds seem to respond to in-farm or local intensification more strongly, bats seem to be more influenced by landscape-scale simplification. Overall, we highlight the importance of the structural complexity of olive groves for birds and bats, an aspect that should be considered in the design of agricultural policies aiming to promote biodiversity conservation.
- Distance to edges, edge contrast and landscape fragmentation: interactions affecting farmland birds around forest plantationsPublication . Reino, Luís; Beja, Pedro; Osborne, Patrick; Morgado, Rui; Fabião, António; Rotenberry, JohnAfforestation often causes direct habitat losses for farmland birds of conservation concern, but it is uncertain whether negative effects also extend significantly into adjacent open land. Information is thus required on how these species react to wooded edges, and how their responses are affected by edge and landscape characteristics. These issues were examined in Mediterranean arable farmland, using bird counts at 0, 100, 200, 300 and >300 m from oak, pine and eucalyptus edges, embedded in landscapes with variable amounts and spatial configurations of forest plantations. Bird diversity declined away from edges, including that of woodland, farmland and ground-nesting birds. Positive edge responses were also found for overall and woodland bird abundances, and for five of the nine most widespread and abundant species (Galerida larks, stonechat, linnet, goldfinch and corn bunting). Strong negative edge effects were only recorded for steppe birds, with reduced abundances near edges of calandra larks and short-toed larks, but not of little bustards and tawny pipits. Edge contrast affected the magnitude of edge effects, with a tendency for stronger responses to old and tall eucalyptus plantations (hard edges) than to young and short oak plantations (soft edges). There were also species-specific interactions between edge and fragmentation effects, with positive edge responses tending to be strongest in less fragmented landscapes, whereas steppe birds tended to increase faster away from edges and to reach the highest species richness and abundances in large arable patches. Results suggest that forest plantations may increase overall bird diversity and abundance in adjacent farmland, at the expenses of steppe birds of conservation concern
- Distance to edges, edge contrast and landscape fragmentation: interactions affecting farmland birds arounf forest plantationsPublication . Fabião, António; Reino, Luís; Osborne, Patrick E.; Beja, Pedro; Morgado, Rui; Rotenberry, John T.Afforestation often causes direct habitat losses for farmland birds of conservation concern, but it is uncertain whether negative effects also extend significantly into adjacent open land. Information is thus required on how these species react to wooded edges, and how their responses are affected by edge and landscape characteristics. These issues were examined in Mediterranean arable farmland, using bird counts at 0, 100, 200, 300 and >300 m from oak, pine and eucalyptus edges, embedded in landscapes with variable amounts and spatial configurations of forest plantations. Bird diversity declined away from edges, including that of woodland, farmland and ground-nesting birds. Positive edge responses were also found for overall and woodland bird abundances, and for five of the nine most widespread and abundant species (Galerida larks, stonechat, linnet, goldfinch and corn bunting). Strong negative edge effects were only recorded for steppe birds, with reduced abundances near edges of calandra larks and short-toed larks, but not of little bustards and tawny pipits. Edge contrast affected the magnitude of edge effects, with a tendency for stronger responses to old and tall eucalyptus plantations (hard edges) than to young and short oak plantations (soft edges). There were also species-specific interactions between edge and fragmentation effects, with positive edge responses tending to be strongest in less fragmented landscapes, whereas steppe birds tended to increase faster away from edges and to reach the highest species richness and abundances in large arable patches. Results suggest that forest plantations may increase overall bird diversity and abundance in adjacent farmland, at the expenses of steppe birds of conservation concern.
- Effects of changed grazing regimes and habitat fragmentation on Mediterranean grassland birdsPublication . Reino, Luís; Porto, Miguel; Morgado, Rui; Moreira, Francisco; Fabião, António; Santana, Joana; Delgado, Ana; Gordinho, Luís; Cal, João; Beja, PedroIn Iberian cereal-steppes, decoupling of payments from current production levels through the Single Farm Payment raised concerns regarding the potential for land abandonment and replacement of sheep by cattle, with eventual negative consequences for declining grassland birds. This study addressed this issue by analysing the responses of five grassland bird species of conservation concern to spatial land use gradients, which are expected to reflect changes potentially associated with the CAP reform. Our results show that both habitat fragmentation and grazing regimes were major drivers of breeding bird densities, though responses to these factors were species-specific. Thekla larks were most abundant in landscapes with small grassland patches and high edge density, whereas calandra larks were abundant only in large expanses of continuous open farmland habitat. Little bustard and short-toed lark densities declined in highly fragmented landscapes, but they appeared to tolerate or even benefit from low to moderate levels of open habitat fragmentation. Corn buntings were little affected by landscape patterns. At the field scale, little bustard and corn bunting densities were highest in fields grazed by cattle, whereas short-toed larks were mostly associated with sheep pastures. Short-toed larks and Thekla larks were most abundant in old fallow fields where cattle was largely absent, whereas corn buntings showed the inverse pattern. These results confirm the view that the same agricultural policies may be favourable for some species of conservation concern but detrimental to others, and so they cannot be assumed to bring uniform conservation benefits.
- A food web approach reveals the vulnerability of biocontrol services by birds and bats to landscape modification at regional scalePublication . Herrera, José M.; Silva, Bruno; Jiménez-Navarro, Gerardo; Barreiro, Silvia; Melguizo-Ruiz, Nereida; Moreira, Francisco; Vasconcelos, Sasha; Morgado, Rui; Rodriguez-Perez, JavierPest control services provided by naturally occurring species (the so-called biocontrol services) are widely recognized to provide key incentives for biodiversity conservation. This is particularly relevant for vertebrate-mediated biocontrol services as many vertebrate species are of conservation concern, with most of their decline associated to landscape modification for agricultural purposes. Yet, we still lack rigorous approaches evaluating landscape-level correlates of biocontrol potential by vertebrates over broad spatial extents to better inform land-use and management decisions. We performed a spatially-explicit interaction-based assessment of potential biocontrol services in Portugal, using 1853 pairwise trophic interactions between 78 flying vertebrate species (birds and bats) and 53 insect pests associated to two widespread and economically valuable crops in the Euro-Mediterranean region, olive groves (Olea europaea subsp. europaea) and vineyards (Vitis vinifera subsp. vinifera). The study area was framed using 1004 square cells, each 10 × 10 km in size. Potential biocontrol services were determined at all those 10 × 10 km grid-cells in which each crop was present as the proportion of the realized out of all potential pairwise interactions between vertebrates and pests. Landscape correlates of biocontrol potential were also explored. Our work suggests that both birds and bats can effectively provide biocontrol services in olive groves and vineyards as they prey many insect pest species associated to both crops. Moreover, it demonstrates that these potential services are impacted by landscape-scale features and that this impact is consistent when evaluated over broad spatial extents. Thus, biocontrol potential by vertebrates significantly increases with increasing amount of natural area, while decreases with increasing area devoted to target crops, particularly olive groves. Overall, our study highlights the suitability of our interaction-based approach to perform spatially-explicit assessments of potential biocontrol services by vertebrates at local spatial scales and suggest its utility for integrating biodiversity and ecosystem services in conservation planning over broad spatial extents
- Grassland vegetation height affects bird responses to forest edges in Mediterranean open farmlandPublication . Faria, João; Reino, Luís; Beja, Pedro; Gonçalves, David; Sánchez-Oliver, Juan S.; Moreira, Francisco; Catry, Inês; Rotenberry, John T.; Morgado, Rui; Brotons, Lluís; Dullinger, Stefan; Schindler, Stefan; Santana, JoanaAfforestation affects Mediterranean farmland biodiversity due to loss and fragmentation of grassland habitats. While the influence of landscape context and plantation edges on farmland bird responses to afforestation is well-documented, less is known about the influence of grassland vegetation height and how it interacts with afforestation to influence bird communities. Here, we examined how changes in grassland vegetation height affect bird responses to afforestation in a farmland region in southern Portugal, and how these are affected by plantation type and edge. This region has experienced afforestation with eucalyptus, pine and oak stands, agricultural intensification, and frequent dry periods. To capture local and landscape-level changes, we collected data in two periods (2005 and 2014–15). Grassland vegetation height varied between sampling periods, emerging as a key factor affecting changes observed. Ground-nesting and cereal-associated species increased in abundance with taller vegetation in 2014–15, while in 2005, with drier weather and shorter vegetation, the species associated with ploughed fields were more abundant. Vegetation height effects on bird assemblages depended on plantation type and distance to plantation edges. Farmland bird abundance, including ground-nesting and cereal crops-associated species, increased with taller vegetation, particularly near oak and pine plantations. Conversely, species associated with ploughed fields declined with taller vegetation, especially near eucalyptus plantations. Results highlight complex interactions between vegetation height, plantation type, and edge proximity shaping avian assemblages. This study supports the importance of field and landscape-level management with special focus on grassland vegetation height and landscape heterogeneity for preserving open-farmland birds in fast-changing Mediterranean farmland landscapes.
- Influence of landscape characteristics on carnivore diversity and abundance in Mediterranean farmlandPublication . Pita, Ricardo; Mira, António; Moreira, Francisco; Morgado, Rui; Beja, PedroPredation is increasingly pointed out as one of the factors contributing to population declines of groundnesting farmland birds, though it remains poorly understood how ongoing transformations of agricultural landscapes affect predator assemblages. This study addressed this issue, estimating the contribution of landscape composition and configuration to spatial variation in species richness and abundances of mammalian carnivores across a gradient of agricultural intensification in southern Portugal. The carnivore assemblage was diverse (10 species), but it was largely dominated by just three widespread and abundant species of generalist predators: domestic dog (Canis familiaris), red fox (Vulpes vulpes) and Egyptian mongoose (Herpestes ichneumon). The number of domestic carnivore species and the abundance of cats (Felis catus) increased along with farmland occupation by human dwellings, whereas dogs were not responsive to landscape variables. The species richness of wild carnivores was highest in landscapes with a patchwork of arable fields and semi-natural habitats such as forests and shrubland, though it was also high in irrigated landscapes with dense networks of irrigation channels and tree lines bordering agricultural fields. Irrigation was also positively associated with the abundance of otters (Lutra lutra) and mongooses. Cats, foxes, badgers (Meles meles), and total and wild carnivore abundances, were positively affected by increasing cover by eucalyptus and pine forest plantations. In general, results suggest that the highest diversity and abundance of carnivores in Mediterranean farmlandmay occur inmosaic landscapes with small agricultural fields, high cover by woody vegetation patches and corridors, and many human dwellings. Preventing scrub encroachment and afforestation may thus be necessary to maintain a low predation risk in open farmland habitats, which are often inhabited by ground-nesting birds of high conservation concern. Conversely, keeping shrubland and forest patches within farmed landscapes may be essential where carnivore persistence is a relevant conservation goal
- Mixed effects of long-term conservation investment in Natura 2000 farmlandPublication . Santana, Joana; Reino, Luís; Stoate, Chris; Borralho, Rui; Carvalho, Carlos Rio; Schindler, Stefan; Moreira, Francisco; Bugalho, Miguel N.; Ribeiro, Paulo Flores; Santos, José Lima; Vaz, Alexandre; Morgado, Rui; Porto, Miguel; Beja, PedroEvaluating the effectiveness of conservation funding is crucial for correct allocation of limited resources. Here we used bird monitoring data to assess the effects of long-term conservation investment in a Natura 2000 (N2000) bird protection area (PA), which during two decades benefited from protection regulations, conservation projects, and agri-environment schemes. Variation between 1995–1997 and 2010–2012 in richness and abundance of flagship (Otis tarda, Tetrax tetrax, and Falco naumanni) and specialized fallow field species were more favorable (i.e., increased more or declined less) inside the PA than in a nearby control area. However, the reverse was found for total bird species, farmland, ground-nesting and steppe species, species associated to ploughed fields, and species of European conservation concern. Enhancing the effectiveness of conservation investment in N2000 farmland may require a greater focus on the wider biodiversity alongside that currently devoted to flagship species, as well as improved matching between conservation and agricultural policies.
- Preserving wintering frugivorous birds in agro-ecosystems under land use change: Lessons from intensive and super-intensive olive orchardsPublication . Morgado, Rui; Pedroso, Rui; Porto, Miguel; Herrera, José M.; Rego, Francisco Castro; Moreira, Francisco; Beja, Pedro1. Fleshy fruit production is becoming more intensive worldwide, but how this affects frugivorous birds is poorly known. In the Mediterranean region, intensive and super-intensive olive orchards are fast expanding, potentially affecting millions of wintering songbirds. Here, we test the idea that intensification may benefit frugivorous birds, at least locally, due to increased fruit availability, while negatively affecting the wider wintering bird community due to intensive management, structural simplification and landscape homogenisation. 2. We estimated olive abundance and surveyed birds in early, mid-and late winter, at traditional, intensive and super-intensive orchards in southern Portugal. We used Hierarchical Modelling of Species Communities to relate species richness, prevalence and abundance to management intensity, winter period, olive availability and landscape context, and evaluated the role of frugivory in modulating observed responses. 3. Olive availability was much higher throughout the winter in more intensive than in traditional orchards, both in trees and on the ground. Frugivorous bird abundance was higher in more intensive orchards, and the most abundant frugivorous species (blackcap, song thrush, robin) were positively affected by olive availability and/or increasing landscape cover by olive orchards, while intensification level had relatively minor effects after accounting for other variables. Non-frugivorous richness and abundance were higher in traditional orchards, and many non-frugivorous species had lower prevalence in more intensive orchards or were negatively affected by landscapes dominated by olive cultivation. 4. Synthesis and applications. While negatively affecting the wider bird community, our results suggest that olive farming intensification can contribute to sustaining large numbers of frugivorous birds in the Mediterranean region. As frugivorous birds are not seen as damaging by olive farmers, there is an opportunity to promote their conservation in intensive and super-intensive orchards, which requires management to increase habitat heterogeneity, and to reduce risks such as mortality associated with mechanical harvest and contamination with pesticide residues. Overall, we recommend that efforts to manage farmland biodiversity should consider the impacts and conservation opportunities of fruit crop intensification