Institute Catala dOrnitologia ICO

Barcelona, Spain

Institute Catala dOrnitologia ICO

Barcelona, Spain
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Aizpurua O.,Center De Recherche Public Gabriel Lippmann | Paquet J.-Y.,Aves Natagora | Brotons L.,University of Barcelona | Brotons L.,Institute Catala dOrnitologia ICO | And 2 more authors.
Ecography | Year: 2015

Long-term biodiversity monitoring data are mainly used to estimate changes in species occupancy or abundance over time, but they may also be incorporated into predictive models to document species distributions in space. Although changes in occupancy or abundance may be estimated from a relatively limited number of sampling units, small sample size may lead to inaccurate spatial models and maps of predicted species distributions. We provide a methodological approach to estimate the minimum sample size needed in monitoring projects to produce accurate species distribution models and maps. The method assumes that monitoring data are not yet available when sampling strategies are to be designed and is based on external distribution data from atlas projects. Atlas data are typically collected in a large number of sampling units during a restricted timeframe and are often similar in nature to the information gathered from long-term monitoring projects. The large number of sampling units in atlas projects makes it possible to simulate a broad gradient of sample sizes in monitoring data and to examine how the number of sampling units influences the accuracy of the models. We apply the method to several bird species using data from a regional breeding bird atlas. We explore the effect of prevalence, range size and habitat specialization of the species on the sample size needed to generate accurate models. Model accuracy is sensitive to particularly small sample sizes and levels off beyond a sufficiently large number of sampling units that varies among species depending mainly on their prevalence. The integration of spatial modelling techniques into monitoring projects is a cost-effective approach as it offers the possibility to estimate the dynamics of species distributions in space and over time. We believe our innovative method will help in the sampling design of future monitoring projects aiming to achieve such integration. © 2014 The Authors.

Brotons L.,Autonomous University of Barcelona | Brotons L.,Institute Catala dOrnitologia ICO
Diversity and Distributions | Year: 2012

Aim Temporally replicated observations are essential for the calibration and validation of species distribution models (SDMs) aiming at making temporal extrapolations. We study here the usefulness of a general-purpose monitoring programme for the calibration of hybrid SDMs. As a benchmark case, we take the calibration with data from a monitoring programme that specifically surveys those areas where environmental changes expected to be relevant occur. Location Catalonia, north-east of Spain. Methods We modelled the distribution changes of twelve open-habitat bird species in landscapes whose dynamics are driven by fire and forest regeneration. We developed hybrid SDMs combining correlative habitat suitability with mechanistic occupancy models. We used observations from two monitoring programmes to provide maximum-likelihood estimates for spread parameters: a common breeding bird survey (CBS) and a programme specifically designed to monitor bird communities within areas affected by wildfires (DINDIS). Results Both calibration with CBS and DINDIS data yielded sound spread parameter estimates and range dynamics that suggested dispersal limitations. However, compared to calibration with DINDIS data, calibration with CBS data leads to biased estimates of spread distance for seven species and to a higher degree of uncertainty in predicted range dynamics for six species. Main conclusions We have shown that available monitoring data can be used in the calibration of the mechanistic component of hybrid SDMs. However, if the dynamics of the target species occur within areas not well covered, general-purpose monitoring data can lead to biased and inaccurate parameter estimates. To determine the potential usefulness of a given monitoring data set for the calibration of the mechanistic component of a hybrid SDM, we recommend quantifying the number of surveyed sites that are predicted to undergo habitat suitability changes. © 2012 Blackwell Publishing Ltd.

De Caceres M.,Autonomous University of Barcelona | Brotons L.,Autonomous University of Barcelona | Brotons L.,Institute Catala dOrnitologia ICO | Fortin M.-J.,University of Toronto
Journal of Biogeography | Year: 2013

Aim: We investigate first whether fire regimes resulting from the combination of climate change and fire-fighting policy may affect species distributions in Mediterranean landscapes, and second to what extent distributional dynamics may be constrained by the spatial legacy of historical land use. Location: Catalonia (north-eastern Spain). Methods: We modelled the distributional responses of 64 forest and open-habitat bird species to nine fire-regime scenarios, defined by combining different levels of climate change and fire suppression efficiency. A fire-succession model was used to stochastically simulate land-cover changes between 2000 and 2050 under these scenarios. We used species distribution models to predict habitat suitability and occupancy dynamics under either no dispersal or full dispersal assumptions. Results: Under many simulated scenarios, the succession from shrubland to forest dominated over the creation of new low-vegetation areas derived from wildfires. Consequently, open-habitat specialists were the group most affected by losses of suitable habitat. Fire regimes obtained under scenarios including high fire suppression efficiency resulted in a larger number of bird species experiencing reductions in their distribution area. Main conclusions: Anthropogenic factors, such as historical land-use change and fire suppression, can drive regional distribution dynamics in directions opposite to those expected from climatic trends. This raises the question of what drivers and interactions should be given priority in the prediction of biodiversity responses to global change at the regional scale. © 2013 Blackwell Publishing Ltd.

Sarda-Palomera F.,Center Tecnologic Forestal Of Catalonia | Sarda-Palomera F.,Institute Catala dOrnitologia ICO | Brotons L.,Center Tecnologic Forestal Of Catalonia | Brotons L.,Institute Catala dOrnitologia ICO | And 5 more authors.
Biodiversity and Conservation | Year: 2012

Field monitoring can vary from simple volunteer opportunistic observations to professional standardised monitoring surveys, leading to a trade-off between data quality and data collection costs. Such variability in data quality may result in biased predictions obtained from species distribution models (SDMs). We aimed to identify the limitations of different monitoring data sources for developing species distribution maps and to evaluate their potential for spatial data integration in a conservation context. Using Maxent, SDMs were generated from three different bird data sources in Catalonia, which differ in the degree of standardisation and available sample size. In addition, an alternative approach for modelling species distributions was applied, which combined the three data sources at a large spatial scale, but then downscaling to the required resolution. Finally, SDM predictions were used to identify species richness and high quality areas (hotspots) from different treatments. Models were evaluated by using high quality Atlas information. We show that both sample size and survey methodology used to collect the data are important in delivering robust information on species distributions. Models based on standardized monitoring provided higher accuracy with a lower sample size, especially when modelling common species. Accuracy of models from opportunistic observations substantially increased when modelling uncommon species, giving similar accuracy to a more standardized survey. Although downscaling data through a SDM approach appears to be a useful tool in cases of data shortage or low data quality and heterogeneity, it will tend to overestimate species distributions. In order to identify distributions of species, data with different quality may be appropriate. However, to identify biodiversity hotspots high quality information is needed. © 2012 Springer Science+Business Media B.V.

Romero J.L.,Institute Catala dOrnitologia ICO | Lammertink M.,CONICET | Lammertink M.,Cornell University | Canestro J.P.,Institute Catala dOrnitologia ICO | Canestro J.P.,Autonomous University of Barcelona
Ardeola | Year: 2013

Middle spotted woodpecker Dendrocopos medius is a scarce species in northern Spain and is listed as endangered in Catalonia. We show a marked increase over a 24-year period in a population of the middle spotted woodpecker in the Aran Valley in the eastern Pyrenees in Catalonia. The population increased from two pairs in 1990 to 27 pairs in 2010, expanding south and east into two arms of the valley. The estimated breeding density in 2010 was 0.22 pairs/10 ha. Out of 26 surveyed forests, 54% were occupied by the woodpecker. There was no difference in occupancy rates between small, medium-sized or large forest areas. Breeding territories in mixed-deciduous forest were characterised by the presence of large-diameter pedunculate oaks Quercus robur. We conclude that the middle spotted woodpecker is expanding its range in the Pyrenees, probably due to an increasing presence of mature oak forests. The as-yet-small population size of the middle spotted woodpecker in northeastern Spain, combined with its relatively low density, suggests that forest protection measures should remain in place for this regionally vulnerable species.

Moreno R.,University of Barcelona | Jover L.,University of Barcelona | Diez C.,University of Vigo | Sarda F.,Institute Catala dOrnitologia ICO | And 2 more authors.
PLoS ONE | Year: 2013

Major oil spills can have long-term impacts since oil pollution does not only result in acute mortality of marine organisms, but also affects productivity levels, predator-prey dynamics, and damages habitats that support marine communities. However, despite the conservation implications of oil accidents, the monitoring and assessment of its lasting impacts still remains a difficult and daunting task. Here, we used European shags to evaluate the overall, lasting effects of the Prestige oil spill (2002) on the affected marine ecosystem. Using δ15N and Hg analysis, we trace temporal changes in feeding ecology potentially related to alterations of the food web due to the spill. Using climatic and oceanic data, we also investigate the influence of North Atlantic Oscillation (NAO) index, the sea surface temperature (SST) and the chlorophyll a (Chl a) on the observed changes. Analysis of δ15N and Hg concentrations revealed that after the Prestige oil spill, shag chicks abruptly switched their trophic level from a diet based on a high percentage of demersal-benthic fish to a higher proportion of pelagic/semi-pelagic species. There was no evidence that Chl a, SST and NAO reflected any particular changes or severity in environmental conditions for any year or season that may explain the sudden change observed in trophic level. Thus, this study highlighted an impact on the marine food web for at least three years. Our results provide the best evidence to date of the long-term consequences of the Prestige oil spill. They also show how, regardless of wider oceanographic variability, lasting impacts on predator-prey dynamics can be assessed using biochemical markers. This is particularly useful if larger scale and longer term monitoring of all trophic levels is unfeasible due to limited funding or high ecosystem complexity. © 2013 Moreno et al.

Camprodon J.,Center Tecnologic Forestal Of Catalonia | Camprodon J.,University of Vic | Faus J.,Consorci per a la Proteccio i la Gestio dels Espais dInteres Natural del Ripolles | Salvanya P.,Mas el College | And 2 more authors.
Acta Ornithologica | Year: 2015

Monocultures of even-aged trees in short rotation are a forest system of low ecological complexity that has been described as unsuitable for the establishment of stable populations of forest birds. However, key habitat quality cues could make them attractive to forest specialists. This paper assesses the suitability of poplar plantations in the northeast of the Iberian Peninsula for a forest specialist, the Lesser Spotted Woodpecker Dendrocopos minor. Poplar stands occupy a small area of an agroforestry mosaic landscape where semi-natural Mediterranean woodland is predominant. Population size, nesting success, home ranges and habitat selection were studied by radio-tracking and monitoring during the breeding season and the winter. Poplar plantations were preferentially selected for breeding and foraging in the spring and the winter. Home ranges in the breeding season and the winter (32.4 and 438.5 ha, respectively) were similar to those observed in semi-natural woodlands that have been studied in Europe. However, population density (0.25 territories/100 ha) was lower than that described in most European semi-natural woodlands. Nesting success was low (0.54), due to strong competition with other cavity nesters, predation of nests by the Greater Spotted Woodpecker, and loss of one of the adults. Fifty per cent of the foraging activity during the breeding season took place in an area of 180 metres around the nest. The amount of standing dead wood in poplar stands was much higher than in the surrounding habitats and source areas. The moderate breeding success and the high rate of adult predation may suggest that poplar plantations act as an ecological trap, in which standing dead wood may be a habitat quality cue that attracts birds to this non-ideal habitat. Poplar plantations become even less suitable when most of the available habitat is felled at the same time. Suitable planning of poplar plantation rotations and recovery of riparian forest is the best way to ensure the survival of Lesser Spotted Woodpecker populations in the long term. © 2015, BioOne. All rights reserved.

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