New Publication: Don't mess with encounter probabilities!

Tavecchia, G., Gimenez, O., Choqut, R., Oro, D., Tenan, S. and Sanz-Aguilar, A. 2021.The trap of hidden processes: Why ‘quick & dirty’ methods to estimate mortality are not always good. A comment to De Pascalis et al. (2020) Biological Conservation, 109057, doi: 10.1016/j.biocon.2021.109057

CMRR models can be difficult to build and many conservation biologists are tempted to shortcut them for simpler, ‘quick & dirty’, methods, trading difficulty with the lack of precision. In some particular cases, it is a winning trade, however, in most cases, it is a very hazardous practice. The proportion of animal seen alive vs those seen dead depends, by definition, on the detection probability, p, that an animal alive is detected and on the probability, λ, that a dead animal is found or retrieved (c) and the tag reported (r), with λ = c*r. Not taking thi into acocunt would lead to biased estimates. Explore scenarios through an R shiny application provided at https://github.com/oliviergimenez/bias_recovery.

Yellow Legged Gull campaign on the starting blocks!

The Yellow-legged gull campaign is on the starting blocks. Last year it has been difficult due to the lockdown in the middle of the breeding season. This year we are ready to catch up with a new fieldwork campaign in Ibiza and some extra help. We are warming up with some press notes and radio interview.

Illustration by Pelopanton

A press note about the project here and a radio interview by Dr. Ana Sanz-Aguilar here 

Ph.D. with the GEDA

Guillermo Gomez Perez will begin his doctorate in Ecology at the Universidad Cumplutense of Madrid on the demography of Griffon vultures in central Spain. 

He will be supervised by Dr Ana Sanz-Aguilar (GEDA- IMEDEA, CSIC/UIB), Dr. Martina Carrete (Pablo Olavide University) and Dr Guillermo Blanco (Natural History Museum, CSIC). Welcome Guillermo!

New publication on seabirds and stable isotopes !

Ramírez F, Vicente-Sastre D, Afán I, Igual JM, Oro D, Forero MG (2021) Stable isotopes in seabirds reflect changes in marine productivity patterns. Mar Ecol Prog Ser 662:169-180. https://doi.org/10.3354/meps13615

 ABSTRACT: Seabirds have been proposed as suitable candidates for tracking and monitoring changes in marine systems (bioindicators). However, their suitability depends on our ability to link the large degree of environmental variability inherent to marine systems with a few, relevant, and accessible signals (biomarkers) informing on changes in their feeding behavior or reproductive performance. We combined satellite remote-sensing records with stable isotope data (δ¹⁵N and δ¹³C) and breeding parameters (fledging success) spanning several years (2001-2014) to investigate the ecological responses to environmental variability by 2 sympatric seabirds inhabiting the western Mediterranean: Scopoli’s shearwater Calonectris diomedea and Cory’s shearwater C. borealis. 

Both species showed similar annual variations in their stable isotopic composition, likely as a response to the trophic consequences of changes in the magnitude and timing of the annual peak in marine productivity (as proxied by satellite imagery of chlorophyll a concentrations). In contrast, no relevant responses were observed in their breeding performance, suggesting that their life-history strategy has evolved to constancy in breeding success, which diminishes its value as a biomarker of changes in marine productivity patterns. Despite this limitation, combining remote sensing and stable isotopes in seabirds is a reliable and powerful tool for the early detection of fine-scale, climate-driven changes in marine productivity patterns and its cascading effects across communities and trophic levels, especially under the current scenario of ocean warming. 

New publication on eradication of introduced fish !

Tiberti, R, Buchaca, T, Boiano, D, Knapp, R. A., Rovira, Q. P, Tavecchia, G, Ventura, M, Tenan, S., 2021. Alien fish eradication from high mountain lakes by multiple removal methods: Estimating residual abundance and eradication probability in open populations. J Appl Ecol. 2021; 00: 1– 14. https://doi.org/10.1111/1365‐2664.13857

1. Invasive alien species are among the most important threats to biodiversity. Plans for their eradication have been implemented worldwide but estimating residual population size and eradication probability to assess removal success is complicated by the imperfect detection of residual individuals.
2. Most methods to assess residual abundance and eradication probability rely on the often unrealistic assumption that a population is closed to mortality and recruitment processes during the implementation of removal actions. We extended existing removal models and developed a novel analytical approach to estimate residual population size and derive eradication probability in open populations while accounting for multiple removal methods.
3. We apply this approach to 20 eradication projects in Europe and the United States that used mechanical methods to return high mountain lakes to their original fishless condition.
4. The new removal model incorporates (a) a mechanistic description of the ecological process underlying survival and recruitment probabilities during the eradication period and (b) the use of multiple, concomitant removal methods (i.e. electrofishing, gillnetting, fyke‐netting) at multiple sites simultaneously.
   
5. We used a subset of ‘control’ lakes where eradication success was confirmed by more than 5 years of post‐removal surveys to validate the model. For these lakes, eradication success, evaluated by whether the 95% Bayesian credible interval for estimated residual population size encompassed values of <2 individuals, was confirmed in 13 out of 15 lake‐by‐species case studies. In addition, the model correctly assigned an eradication probabilities equal to 0 for the eradications that are still in progress.
6. Synthesis and applications. Our study provides insights into the dynamics of fish populations subject to eradication in high mountain lakes of different countries. In addition, the analytical approach proposed accounts for demographic processes and multiple removal methods in multiple sites and seasons. It can represent an informative tool to estimate residual population size and eradication probability of alien species to optimize eradication efforts and efficacy of conservation actions. The extension to open populations makes the approach useful to evaluate long‐term eradication plans.

New Publication on White Stork and landfill!

Lopéz-Garcia, A., Sanz-Aguilar, A. and Aguirre, J. I. 2021.The trade-offs of foraging at landfills: Landfill use enhances hatching success but decrease the juvenile survival of their offspring on white storks (Ciconia ciconia) Science of the Total Environment doi.org/10.1016/j.scitotenv.2021.146217

Abstract:During the last decades, landfills have become a valuable food source for wildlife, being in some cases determinants of large avian population increases. Superabundant food resources at landfills can increase reproductive and/or survival parameters; however, negative effects such as intoxication, plastic ingestion, skeletal deformities, unbalanced oxidative stress, and other health problems have also been reported. White stork (Ciconia ciconia) commonly benefits from landfill resources. Here, we evaluate potential landfill effects on demographic parameters (reproduction and offspring survival) at the individual level in a single population. Our results show that a more intense use of landfills by breeders has a positive effect on hatching success but a negative effect on juvenile survival probability after emancipation, at least during the first year of life. High amount of food and proximity to landfill may explain their beneficial effect on reproductive parameters. On the other hand, poor quality food, pollutants, and pathogens acquired during early development from a diet based on refuse may be responsible for reduced future survival probability. Consequently, both positive and negative effects were detected, being foraging at landfills at low to medium levels the better strategy. Although our study shows that intense foraging on rubbish can imply both costs and benefits at an individual level, the benefits of superabundant food provisioning observed at population level by other studies cannot be ignored. Management actions should be designed to improve natural food resources, reduce non-natural mortality and/or human disturbances to guarantee the species viability under current European Union regulations designed to ban open-air landfills in a near future.

From Lopéz-García et al.

 

 

 

New Publication on vulture natal dispersal!

Serrano, D., Cortés-Avizanda, A., Zuberogoitia, I., Blanco, G. et al. 2021. Phenotypic and environmental correlates of natal dispersal in a long-lived territorial vulture. Scientific Reports 11, 5424, doi:10.1038/s41598-021-84811-8

Abstract: Natal dispersal, the movement between the birth and the first breeding site, has been rarely studied in long-lived territorial birds with a long-lasting pre-breeding stage. Here we benefited from the long-term monitoring programs of six populations of Egyptian vultures (Neophron percnopterus) from Spain and France to study how the rearing environment determines dispersal. For 124 vultures, we recorded a median dispersal distance of 48 km (range 0–656 km). Linear models were used to assess the effect of population and individual traits on dispersal distance at two spatial scales. Dispersal distances were inversely related to vulture density in the natal population, suggesting that birds perceive the abundance of conspecifics as a signal of habitat quality. This was particularly true for declining populations, so increasing levels of opportunistic philopatry seemed to arise in high density contexts as a consequence of vacancies created by human-induced adult mortality. Females dispersed further than males, but males were more sensitive to the social environment, indicating different dispersal tactics. Both sexes were affected by different individual attributes simultaneously and interactively with this social context. These results highlight that complex phenotype-by-environment interactions should be considered for advancing our understanding of dispersal dynamics in long-lived organisms.

New publication on albatross and large petrels!

Beal, M, Dias, M.P,...[Igual, J.-M.]...,Catry, P., 2021.Global political responsibility for the conservation of albatrosses and large petrels. Science Advances doi: 10.1126/sciadv.abd7225

Abstract: Migratory marine species cross political borders and enter the high seas, where the lack of an effective global management framework for biodiversity leaves them vulnerable to threats. Here, we combine 10,108 tracks from 5775 individual birds at 87 sites with data on breeding population sizes to estimate the relative year-round importance of national jurisdictions and high seas areas for 39 species of albatrosses and large petrels. Populations from every country made extensive use of the high seas, indicating the stake each country has in the management of biodiversity in international waters. We quantified the links among national populations of these threatened seabirds and the regional fisheries management organizations (RFMOs) which regulate fishing in the high seas. This work makes explicit the relative responsibilities that each country and RFMO has for the management of shared biodiversity, providing invaluable information for the conservation and management of migratory species in the marine realm

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New Publication on ecosystem service mapping!

Ceausu, S., Apaza-Quevedo, A., Schmid,M., Martín-López, B., Cortés-Avizanda,A., Maes, J., Brotons, L., Queiroz, C., Pereira, H.M., 2021 Ecosystem service mapping needs to capture more effectively the biodiversity important for service supply. Ecosystem services 101259

Abstract:Large scale mapping of ecosystem services and functions (ES) is an important tool for researchers and policy makers to inform nature management and policies but it relies mainly on ES modelled with biophysical data such as land cover, henceforth biophysical ES. Other ES, henceforth species-based ES, are modelled at small scales based on species providers. 

As species-based ES are rarely included in multi-service, large-scale spatial assessments, we do not know if these assessments provide accurate information for managing the biodiversity important for species-based ES. We calculate and map weighted provider richness (WPR) for 9 species-based ES by weighting species data in Europe by their functional efficiency derived from functional trait databases. We compare WPR spatial patterns with those of 9 biophysical ES at continental and national scales in Europe. We find positive correlations at continental scale, and weaker positive correlations or neutral relationships at national scale between biophysical ES and WPR. Patterns of synergies and trade-offs for WPR are different from those of biophysical ES and change from continental to national scale. WPR for most species-based ES are synergistic with each other but WPR for existence value has the weakest synergies with other WPRs. Biodiversity data is still insufficient to truly map species-based ES at large scales but WPR can represent the next step forward for spatial ES assessments. A lack of spatial information on species-based ES in large-scale assessments leads to inaccurate information on ES distribution, and their synergies and trade-offs, which can lead to misguided management and conservation decisions.