The 2017 Workshop on capture-recapture has ended

The Workshop on capture-mark-recapture-recovery analyses has ended. It has been very interesting to know abut new exciting systems, marking methods, ecological questions and above all to meet new colleagues. We learned about turtles, shearwaters, voles, goose, vulture, penn shells..etc..


 Thanks for coming! 
The next workshop in 2018, last week of November, as always!

New publication on Storm Petrel population dynamics !

Matović, N, Cadiou, B, Oro, D. and Sanz-Aguilar A. 2017. Disentangling the effects of predation and oceanographic fluctuations in the mortality of two allopatric seabird populations

 Population Ecology, 59:225–238, doi: 10.1007/s10144-017-0590-5

 

Photo By A. Caldas (Flickr)

Abstract : Life-history traits of migratory seabirds are influenced by changing conditions at breeding and wintering grounds. Climatic conditions and predation are known to impact populations’ survival rates, but few studies examine their effect simultaneously. We used multievent capture–recapture models to assess mortality due to environmental conditions and predation in breeding European storm petrels (Hydrobates pelagicus) in two allopatriccolonies  (Mediterranean and Atlantic). Predatory mortality at the colonies showed annual variation, being around 0.05 in certain years. Mortality at sea differed between the two oceanic basins, and was lower in the Mediterranean colony [0.11, 95% CI (0.09, 0.14)] when compared to the Atlantic colony [0.18, 95% CI (0.15, 0.22)]. The Western Mediterranean Oscillation index (WeMOi)  explained 57%of the temporal variability in mortality of Mediterranean breeders. In comparison, 43% of the temporal variability in mortality of Atlantic breeders was explained by the winter St Helena index (wHIX) and El Niño-Southern Oscillation index (wENSO). Our results suggest that Mediterraneanbreeders remain in this basin for wintering where they may face lower migratory costs and more favourable environmental conditions. In contrast, Atlantic breeders’ mortality may be due to higher cost of migration, changing upwelling conditions in the Benguela current  and heavy storms over their migratory route during La Niña events. This study underlines the importance of modelling separately different causes of mortality when testing the effects of climatic covariates.

 

New publication : surviving at high elevation !

Bastianelli, G., Tavecchia, G., Meléndez, L. Seoane, J., Obeso, J. R. and Laiolo, P. 2017.
Surviving at high elevations: an inter- and intra-specific analysis in a mountain bird community Oecologia doi:10.1007/s00442-017-3852-1

Photo: e.wikipedia.org

Abstract: Elevation represents an important selection agent on self-maintenance traits and correlated life histories in birds, but no study has analysed whether life-history variation along this environmental cline is consistent among and within species. In a sympatric community of passerines, we analysed how the average adult survival of 25 open-habitat species varied with their elevational distribution and how adult survival varied with elevation at the intra-specific level. For such purpose, we estimated intra-specific variation in adult survival in two mountainous species, the Water pipit (Anthus spinoletta) and the Northern wheatear (Oenanthe oenanthe) in NW Spain, by means of capture–recapture analyses. At the inter-specific level, high-elevation species showed higher survival values than low elevation ones, likely because a greater allocation to self-maintenance permits species to persist in alpine environments.

Photo : larsfoto.es

At the intra-specific level, the magnitude of survival variation was lower by far. Nevertheless, Water pipit survival slightly decreased at high elevations, while the proportion of transient birds increased. In contrast, no such relationships were found in the Northern wheatear. Intra-specific analyses suggest that living at high elevation may be costly, such as for the Water pipit in our case study. Therefore, it seems that a species can persist with viable populations in uplands, where extrinsic mortality is high, by increasing the investment in self-maintenance and prospecting behaviours.

Workshop on Capture-Recapture and -Recovery at MUSE ended

The Workshop on Capture-Recapture and -Recovery at MUSE in collaboration with Dr. S. Tenan ended last Friday. It has been a very nice and interesting meeting with data on wolves, migratory birds, wild boards, gulls... surrounded by Trento mountains. Thank you all and thank to Simone for organizing this. The next workshop is scheduled in Mallorca this November.

New Publication on Storm Petrels !

Hernández, N., Oro, D and Sanz-Aguilar, A., Environmental conditions, age and senescence differentially influence survival and reproduction in the Storm Petrel. 2017. Journal of Ornithology. Volume 158, pp 113–123. DOI: 10.1007/s10336-016-1367-x

Abstract: Demographic parameters in wild populations are expected to be shaped by individual covariates and environmental variability. Thus, the understanding of the effects of age and/or environmental conditions on variability in vital rates is of special importance in ecological and evolutionary studies. Early age-related improvements in survival and reproduction and later declines due to senescence are expected, above all in long-lived species. Survival in these species is predicted to be a more conservative parameter than reproduction, thereby giving rise to less temporal variability. We studied age-dependent patterns of survival and breeding success in a long-lived seabird, the Mediterranean Storm Petrel Hydrobates pelagicus melitensis, and the additive influence of individual heterogeneity and environmental climatic variables using 22 years of individual-based data (1993–2014). The North Atlantic Oscillation index (NAO) and sea surface temperature (SST) were selected as proxies of environmental conditions in both breeding and wintering areas. Our results show that vital rates improved with age for both survival and breeding success. A slow effect of senescence at older ages was detected for breeding success, whereas models did not disentangle the occurrence or the absence of actuarial senescence. Reproduction was also influenced by the age of first observed reproduction: at the same age, more experienced birds that recruited earlier had a higher breeding success than less experienced ones. Breeding success (but not survival) also showed great temporal variability in accordance with theoretical predictions. Neither the NAO nor the SST explained this variability, probably because petrels feed on lower trophic levels than most pelagic seabirds and other physical features such as river runoffs and winds may be involved, as well as other environmental stressors such as predation by sympatric gulls.

The Capture-Recapture-Recovery Workshop 2016 has ended : see you next year !

The introductory course on “CAPTURE-RECAPTURE AND CAPTURE–RECOVERY ANALYSIS FOR THE STUDY OF ANIMAL POPULATIONS” has ended. 
It has been an occasion to share thoeretical and practical aspects of CMR analyses, to learn about snails, feral cats, tropical frogs & Co.  See you next year, last week of November! (visit also our facebook page)

New Publication on modelling dispersal to unobservable sites !

Tavecchia, G., Sanz-Aguilar, A. and Cannell, B. Modelling survival and breeding dispersal to unobservable nest stes. Wildlife Research 43(5) 411-417 http://dx.doi.org/10.1071/WR15187

Context: Demographic parameters in wildlife populations are typically estimated by monitoring a limited number of individuals in observable sites and assuming that these are representative of the whole population. If individuals permanently disperse to unobservable breeding sites, recruitment and immature survival are expected to be negatively biased and breeding-site fidelity cannot be measured.

Photo: Leighton De Barros

Aims: To develop a method to obtain unbiased estimates of survival, recruitment and breeding dispersal when individuals can move to, or recruit in, unobservable sites.
Methods: We used the flexibility of multi-event capture–recapture models to estimate dispersal and recruitment to unobservable sites, merging observations made at two sites within the same breeding locations. We illustrated the model with data on little penguin (Eudyptula minor) breeding in artificial as well as in natural nests. Natural nests are unknown or inaccessible and birds in these sites remain unobservable. Encounters at beaches surrounding the colony suggested that marked animals can permanently move to unobservable nests. We built the multi-event model considering two possible states of the individuals (alive breeding in a nest box and alive in a natural nest) and three types of observations (encountered at a nest only, encountered at the beach only and encountered at both places). This model ensured that the breeding dispersal to unobservable places became estimable.
Key results: Results indicate that the estimated survival was 8% higher than when recaptures at artificial nests were analysed alone. Also, fidelity to artificial nests was 12% lower than to natural nests. This might reflect the greater availability of natural sites or, alternatively, a heterogeneity between these two types of nest.
Conclusions: We obtained an estimate of local survival of little penguins breeding at Penguin Island that incorporates the permanent migration to unobservable sites and found an asymmetric dispersion towards natural nests.
Implication: Our conclusions suggest a need for more careful treatment of data derived from artificial sites alone, as demographic parameters might be underestimated if animals prefer natural breeding sites or if they are in greater proportion compared with artificial ones. The analytical approach presented can be applied to many biological systems, when animals might move into inaccessible or unobservable breeding sites.

WORKSHOP ON CAPTURE-RECAPTURE AND -RECOVERY ANALYSIS, 21-25 November, Mallorca, Spain

UPCOMING WORKSHOP : WORKSHOP ON CAPTURE-RECAPTURE AND -RECOVERY ANALYSIS

21-25 November 2016, Mallorca, SPAIN

Photo: F. Sergio

The course aims to introduce students, researchers and environmental managers to the theory and practical aspects of the analysis of capture-mark-recapture and –recovery data to estimate survival, recruitment and dispersal probabilities. The course is based on theoretical classes as well as practical sessions with real and simulated data.



Information here  or contact directly  g.tavecchia-at-uib.es
 
 Dead line for registration: October 2016
Places: 20

New Publication on the rescue effect in Scopoli's Shearwaters !

Sanz-Aguilar, A.; Igual, J.M.; Tavecchia, G.; Genovart, M; Oro, D. 2016. When immigration mask threats: The rescue effect of a Scopoli’s shearwater colony in the Western Mediterranean as a case study. Biological Conservation, 198, 33–36. doi:10.1016/j.biocon.2016.03.034

Photo: M. Gomila

Abstract: Populations of long-lived species are highly sensitive to increases in mortality, but a loss of breeders can be compensated for by recruitment of local individuals or immigrants. Populations maintained through immigration can be sinks, jeopardizing the viability of the metapopulation in the long term when additive mortality from anthropogenic impacts occurs. Thus, the correct identification of whether a breeding population is maintained by local recruitment or by immigration is of special importance for conservation purposes. We developed robust population models to disentangle the importance of local recruitment and immigration in the dynamics of a Western Mediterranean population of Scopoli's shearwater Calonectris diomedea showing low adult survival but stable breeding numbers. Our results show that the shearwater population is not self-maintained but rescued by immigration: yearly immigrants recruiting in the population represents ~ 10–12% of total population size. We believe that this situation may be common to other Western Mediterranean populations, currently acting as sinks. We recommend urgent demographic studies at large core colonies to evaluate the global conservation status of the species.

 
A press release of the publication has just appeared. You can read the spanish version here

New Publication on Indo-Pacific bottlenose dolphins !

Pérez-Jorge, S., Gomes, I., Hayes, K., Corti, G., Louzao, M., Genovart, M. and Oro, D. 2016 : Effects of nature-based tourism and environmental drivers on the demography of a small dolphin population Biological Conservation: doi:10.1016/j.biocon.2016.03.006

Abstract: Many marine top predators are experiencing significant declines due to anthropogenic impacts, and therefore reliable monitoring is essential to understand their population dynamics. We used Pollock's robust design capture–recapture modelling to assess the influence of oceanographic variables, artisanal fisheries and human disturbance on several demographic parameters (abundance, temporary emigration and survival) of the Indo-Pacific bottlenose dolphin (Tursiops aduncus), using long-term data on marked individuals from East Africa.

Photo-identification data was collected over 551 boat-based surveys between 2006 and 2009, with 137 individuals identified. Our best fitting model indicated that exposure to tourism (represented by the number of tourist boats) increased the probability of dolphins seasonally emigrating from the study area. The return rate of temporary emigrants was negatively linked to the seasonal sea surface temperature, probably associated with food availability. That model supported the existence of heterogeneity in annual local survival estimates, with transient dolphins showing a lower value than resident individuals (0.78 and 0.98, respectively). Furthermore, abundance estimates showed a small population size ranging from 19 individuals (95% CI: 11–33) to a maximum of 104 dolphins (95% CI: 78–139). This small population, together with their high site fidelity and coastal distribution, might be particularly vulnerable to human disturbances. This study highlights the influence of environmental and anthropogenic factors on dolphin demography and population dynamics and the need to integrate these drivers to provide robust evidences for conservation stakeholders in an adaptive management framework.

YLG 2016 campaign just started !

Photo F.Pezzo

The 2016 Yellow Legged Gull campaign has just started at Dragonera island. 
Birds are building their nests while few are already incubating. A good moment to read rings.

New Publication on Lilford's wall lizard !!

Rotger, A., Smith, J.J., Igual, J.-M. and Tavecchia, G., 2016: Relative role of population density and climatic factors in shaping the body growth rate of Lilford’s Wall Lizard (Podarcis lilfordi). Canadian Journal of Zoology. doi: 10.1139/cjz-2015-0188

 Abstract: The growth rate in small reptiles is modulated by per-capita food resources and recent evidence suggested that this constraint is the mechanism underlying differences between cohorts. Per-capita food resources depend on population size and climatic factors, but their relative role in explaining the variations in growth rate is unclear.

Photo: G. Tavecchia

We used morphological data collected over 6 years to model the body growth of an insular lizard (Lilford’s Wall Lizard, Podarcis lilfordi (Günther, 1874)). We used nonlinear equations to describe the appropriate length-at-age relationship. For each sex, seasonal growth was observed and the oscillatory von Bertalanffy curve was fitted to the data. Three age classes were recognized, and we investigated the relative role of density, spring rainfall, and temperature in explaining the variation of the growth rate in each sex-by-age class. Results showed that the relative role of density and climatic factors varied according to the age considered. While population size and temperature had a negative effect on the growth rate of juveniles, rainfall had a positive influence on the growth of subadults. Adult growth was near zero and constant over time. The different role of density-dependent and climatic factors in explaining age-dependent growth rate provides an important insight in understanding lizard population dynamics and life-history tactics.

Ph.D. defense: Carles Carboneras Malet !

From Carboneras et al. 2013 Pop Ecol

Carles Carboneras succesfully defended his Ph. D. titled: "Birds population dynamics in the wintering season: the case of  the Mediterranean Gull, Larus Melanocephalus" at the University of Barcelona.

Photo: C Carboneras

 

Carles' work focussed on the wintering startegy and migratory routes of Mediterranean Gulls marked in several breeding areas in middle and northern Europe.

The Ph.D was supervised by Dr G. Tavecchia and Dr. M. Genovart.


You can read Carles' s work here

Carboneras, C., 2016. Birds Population dynamics in the wintering season: the case of  the Mediterranean Gull, Larus Melanocephalus. University of Barcelona, Spain.
 
Well done Carles!

New publication on Lesser kestrel demography in Sicily!

Di Maggio, R., Campobello, D., Tavecchia, G. and Sará M. 2016: Habitat- and density-dependent demography of a colonial raptor in Mediterranean agro-ecosystems  Biological Conservation, vol 193 pag 116-123. doi:10.1016/j.biocon.2015.11.016

Abstract: Agricultural intensification is considered the major cause of decline in farmland bird populations, especially in the Mediterranean region. Food shortage increased by the interaction between agricultural intensification and density-dependent mechanisms could influence the population dynamics of colonial birds. We used demographic data on lesser kestrels (Falco naumanni), a key species of Mediterranean pseudo-steppes, to understand the importance of land-use changes and density-dependent mechanisms in the light of its fluctuating conservation status in the Western Palearctic. Our analysis indicated an important influence of land uses (artichokes, arable and grassland fields) and colony size on kestrel survival rates.

The strong habitat effect revealed the unsuitability of intensive arable lands with respect to extensive grasslands for lesser kestrels. Notably, artichokes, a winter-intensive crop, proved to be a high-quality habitat as they were associated with survival values equal to those of grassland. This is likely due to prey availability and reveals that non-traditional crops may provide suitable habitats for lesser kestrels. Information theory gave strong support to the negative influence of colony size on fecundity, albeit a small one, for its positive effect on survival probability. The estimated population growth rate was negative for all three habitats, indicating a decline over time and urging conservation actions in all of the areas studied. This decline was much higher in colonies surrounded by arable fields. In sensitivity analyses, λ indicated that adult survival was the parameter with the greatest effect on population growth, followed by survival of fledglings and fecundity. Our study showed how the costs and benefits of group living interact with agricultural intensification to drive species demography. In addition, we integrated significant information on one of the largest lesser kestrel populations to fine tune the most effective conservation strategy to prevent the collapse of the species in a relevant part of its range

The 2015 Introductory Course on CMRR analysis has ended: see you next year!

The 2015 Introductory Course on CMRR analysis has ended last friday. Thanks to all participants. We had the opportunity to learn about Oryx and Wolves, Cormorants, Bears, Butterflies, Small mammals, Woodcocks, about hunting, conservations and wind farms.  It has been the opportunity to address scientific questions and, on top of all, to meet nice people.  Thank you again.

Debating about GOF and AIC, of course (apologises for the missing persons, it is the only pic I have)

See you next year, last week of November, as always.

New publication on the survival of Burrowing owls (Athene cunicularia) !

Rebolo-Ifrán, N.,  Carrete, M., Sanz-Aguilar, A., Rodríguez-Martínez, S., Cabezas, S., Marchant, T., Bortolottu, G. and Tella, J. L. (2015). Links between fear of humans, stress and survival support a non-random distribution of birds among urban and rural hábitats. Scientific Reports 5:13723.  DOI: 10.1038/srep13723

Photo: Natalia Rebolo

Abstract:Urban endocrine ecology aims to understand how organisms cope with new sources of stress and maintain allostatic load to thrive in an increasingly urbanized world. Recent research efforts have yielded controversial results based on short-term measures of stress, without exploring its fitness effects. We measured feather corticosterone (CORT_f, reflecting the duration and amplitude of glucocorticoid secretion over several weeks) and subsequent annual survival in urban and rural burrowing owls. This species shows high individual consistency in fear of humans (i.e., flight initiation distance, FID), allowing us to hypothesize that individuals distribute among habitats according to their tolerance to human disturbance. FIDs were shorter in urban than in rural birds, but CORT_f levels did not differ, nor were correlated to FIDs. Survival was twice as high in urban as in rural birds and links with CORT_f varied between habitats: while a quadratic relationship supports stabilizing selection in urban birds, high predation rates may have masked CORT_f-survival relationship in rural ones. These results evidence that urban life does not constitute an additional source of stress for urban individuals, as shown by their near identical CORT_f values compared with rural conspecifics supporting the non-random distribution of individuals among habitats according to their behavioural phenotypes.

GEP at the DEVOTES SUMMER SCHOOL

Sergi Pérez Jorge from the GEP presented the study “Integrative assessment of human dimension on the conservation of the Indo-Pacific bottlenose dolphin in Kenya” at the DEVOTES-EUROMARINE Summer School in Donostia-San Sebastian.

The course explored the potential and recent advances in the integrative assessment of marine systems (based upon strong new monitoring tools, such as genomics), including the various ecosystem components (from plankton to marine mammals), at different scales (from water bodies to regional seas), and in management applications (e.g. to the European Marine Strategy Framework Directive (MSFD), the Water Framework Directive (WFD)).

Introductory course : CAPTURE-MARK-RECAPTURE AND –RECOVERY ANALYSIS

UPCOMING WORKSHOP : 21-26 November 2016 !!!!!

23-27 November 2015, Mallorca, SPAIN

The course aims to introduce students, researchers and environmental managers to the theory and practical aspects of the analysis of capture-mark-recapture and –recovery data to estimate survival, recruitment and dispersal probabilities. The course is based on theoretical classes as well as practical sessions with real and simulated data.

Dead line for registration: 24 September 2015 
Places: 20

New publication on Raptors on Islands

Sanz-Aguilar A, de Pablo F, Donázar JA. Age-dependent survival of island vs. mainland populations of two avianscavengers: delving into migration costs. Oecologia, in press (doi:10.1007/s00442-015-3355-x) 

Abstract: Large terrestrial long-lived birds (including raptors) are typically sedentary on islands, even when they are migratory on the mainland. Density-dependent variation in the age at first breeding has been described as responsible for the long-term persistence of long-lived bird populations on islands. However, sedentary island populations may also benefit from higher survival rates derived from the absence of migration costs, especially for young individuals. Thus, sedentary island populations can mimic a natural experiment to study migration costs. 

Photo: Felix de Pablo

We estimated the age-dependent survival of two sedentary raptors on Menorca Island (Egyptian vultures Neophron percnopterus and red kites Milvus milvus) and compared these estimates with those reported for other migratory and sedentary populations. In Menorca, Egyptian vultures, but not red kites, showed low levels of human-related mortality resulting in extremely high survival probabilities, probably due to different diet choices and behavioral patterns. Juvenile Egyptian vultures and red kites in the studied population had lower survival probabilities than adults. This difference, however, was smaller than those reported for mainland migrant populations, which showed a lower juvenile survival rate. In fact, between-population comparisons suggested that survival of the young in migrant populations may be triggered by mortality factors in wintering areas. In contrast, adult survival may respond to mortality factors in breeding areas. Our results suggest that raptor species that become sedentary on islands may benefit from higher pre-breeder survival prospects in comparison with their mainland migrant counterparts. This fact, in combination with an earlier age at first reproduction, may facilitate their persistence.

Still growing...PhD at the GEP

Enrique Real Garcías joined the GEP for a Ph.D. supported by the MINECO. He will deal with the difficult task of estimating fishery induced mortality of seabirds. His challenge will be to couple bycatch data, seabird surveys and capture-recapture data to estimate the mortality caused by fishery. The project will be developed in collaboration with the Balearic Center of Oceanography (IEO). Welcome Enrique.