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Press Release!

A new press release in the national newspaper "EL PAIS" about the work by A. Sanz-Aguilar y E. Arrondo here

New publication on scavangers and epizootic regulations!

Donázar, J.A., Cortés-Avizanda, A., Ceballos, O., Arrondo, E., Grande, J.M., Serrano, D. 2020. Epizootics and sanitary regulations drive long-term changes in fledgling body condition of a threatened vulture. Ecological Indicators, vol. 113. https://doi.org/10.1016/j.ecolind.2020.106188

Abstract:  Epizootics and deliberate changes in policies affecting the environment may affect large groups of species and the functioning of entire ecosystems. Although these effects often overlap in time, their simultaneous effect is rarely examined despite their importance as causes of current biodiversity loss. Here, based on the monitoring of an Egyptian vulture (Neophron percnopterus) population over thirty-three years (1986–2018), we increase our knowledge about the effects of anthropogenic-induced changes in food availability, both direct (sanitary policies limiting livestock carcass disposal) and indirect (a wild rabbit epizootic), on brood size and body condition of fledglings at nests. We compared the body mass of fledglings of broods with one chick (Single) and two chicks (within which we distinguished First and Second-hatched). The mass of Second-hatched chicks decreased after the plummet in rabbit populations (in the year 1990) and the regulations limiting carcass disposal (2005), reaching minimum values during the period with lowest food availability (i.e. 2005–2013). Recent sanitary legislation allowing carcass disposal by farmers coincides with a slight recovery in the observed body masses. Overall, this study shows that environmental changes of disparate origin can have synergistic effects on individual condition. Conservation of endangered vultures will require multi-targeted conservation plans aimed at ensuring nutritional requirements, in addition to detailed long-term monitoring, in order to detect obscure/masked drivers that affect body condition of fledglings.

New Publication on Urban vs Rural Burrowing owl!

Luna, Á., Palma, A., Sanz-Aguilar, A., Tella, J.L., Carrete, M. 2020. Sex, personality and conspecific density influence natal dispersal with lifetime fitness consequences in urban and rural burrowing owls. PLoS ONE 15(2): e0226089

Abstract: There is a growing need to understand how species respond to habitat changes and the potential key role played by natal dispersal in population dynamics, structure and gene flow. However, few studies have explored differences in this process between conspecifics living in natural habitats and those inhabiting landscapes highly transformed by humans, such as cities. Here, we investigate how individual traits and social characteristics can influence the natal dispersal decisions of burrowing owls (Athene cunicularia) living in urban and rural areas, as well as the consequences in terms of reproductive success and apparent survival. We found short dispersal movements among individuals, with differences between urban and rural birds (i.e., the former covering shorter distances than the latter), maybe because of the higher conspecific density of urban compared to rural areas. Moreover, we found that urban and rural females as well as bold individuals (i.e., individuals with shorter flight initiation distance) exhibited longer dispersal distances than their counterparts. These dispersal decisions have effects on individual fitness. Individuals traveling longer distances increased their reproductive prospects (productivity during the first breeding attempt, and long term productivity). However, the apparent survival of females decreased when they dispersed farther from their natal territory. Although further research is needed to properly understand the ecological and evolutionary consequences of dispersal patterns in transformed habitats, our results provide information about the drivers and the consequences of the restricted natal movements of this species, which may explain its population structuring through restricted gene flow between and within urban and rural areas.

New Publication on mate-finding in tortoises!

Jiménez-Franco, M.V., Giménez, A., Rodgríguez-Caro, R.C., Sanz-Aguilar, A., Botella, F., Anadón, J.D., Wiegand, T., Graciá, E. 2020. Sperm storage reduces the strength of the mate-finding Allee effect. Ecology and Evolution, https://doi.org/10.1002/ece3.6019
 
Abstract: Mate searching is a key component of sexual reproduction that can have important implications for population viability, especially for the mate‐finding Allee effect. Interannual sperm storage by females may be an adaptation that potentially attenuates mate limitation, but the demographic consequences of this functional trait have not been studied. Our goal is to assess the effect of female sperm storage durability on the strength of the mate‐finding Allee effect and the viability of populations subject to low population density and habitat alteration. We used an individual‐based simulation model that incorporates realistic representations of the demographic and spatial processes of our model species, the spur‐thighed tortoise (Testudo graeca).

Photo: wikipedia.org

This allowed for a detailed assessment of reproductive rates, population growth rates, and extinction probabilities. We also studied the relationship between the number of reproductive males and the reproductive rates for scenarios combining different levels of sperm storage durability, initial population density, and landscape alteration. Our results showed that simulated populations parameterized with the field‐observed demographic rates collapsed for short sperm storage durability, but were viable for a durability of one year or longer. In contrast, the simulated populations with a low initial density were only viable in human‐altered landscapes for sperm storage durability of 4 years. We find that sperm storage is an effective mechanism that can reduce the strength of the mate‐finding Allee effect and contribute to the persistence of low‐density populations. Our study highlights the key role of sperm storage in the dynamics of species with limited movement ability to facilitate reproduction in patchy landscapes or during population expansion. This study represents the first quantification of the effect of sperm storage durability on population dynamics in different landscapes and population scenarios.

GEDA and Vulture Conservation Foundation !

The novel project by A. Cortés-Avizanda was promoted by the Vulture Conservation Foundation (VCF). The VCF furnished the GPS/GSM devices that now are providing important data on vulture movements in Mallorca. Ainara's work has been supported by a "Vicenç Mut" fellowship granted by the Government of the Balearic Islands. A new press release on the local newspaper (in Spanish) here

New Publication on Red Palm Weevil!

Sanz-Aguilar, A., Cortés, I., Gascón, I., Martínez, O., Ginard, S., Tavecchia, G., 2020.Modelling pest dynamics under uncertainty in pest detection: the case of the red palm weevil. Biological Invasions. https://doi.org/10.1007/s10530-020-02208-6

Photo from wikimedia commons

Abstract. A common complication in invasive pest management is that the infectious state of the host can be wrongly assessed, leading to biases in the estimation of the prevalence of the pest and on the efficacy of mitigation actions. We designed a multievent model that accommodates uncertainty on host state to investigate the dynamics of the infestation of Phoenix canariensis by the invasive Rhynchophorus ferrugineus.  Since 2011, the council of Palma city (Mallorca Island, Spain) applied preventive, curative and destructive treatments to public Phoenix palms. A year later awareness campaigns focused on every palm owner in an attempt to control the plague. We estimated the probability of infestation and assessed the efficiency of mitigation measures, awareness campaigns and palm-dependent covariates. Our results show that infestation probabilities were higher for palms infested in the previous year than for healthy palms and it decreased substantially over time as a results of mitigation measures and awareness campaigns. Palms surrounded by treated palms had a lower probability of being infested than palms surrounded by untreated palms, i.e. private palms before awareness campaigns implementation. Our results highlight the key role of awareness campaigns and public participation for invasive species control.

New Publication on vultures and human activities!

Arrondo, E, Sanz-Aguilar, A., Pérez-Garcia, J., Cortés-Avizanda, A., Sánchez-Zapata, J.A., Donazár, J.A. 2020 Landscape anthropization shapes the survival of a top avian scavenger Biodiversity and Conservation.pp 1–15  https://doi.org/10.1007/s10531-020-01942-6)

Photo: M. Gomila

Abstract. Events of non-natural mortality in human-dominated landscapes are especially challenging for populations of large vertebrates with K strategies. Among birds, vultures are one of the most threatened groups experiencing sharp population declines due to non-natural mortality. Factors causing non-natural mortality are usually studied separately. However, the potential use of an integrated index able to predict large-scale mortality risks of avian scavengers could be especially useful for planning conservation strategies.
Here, we used the Human Footprint index to examine the impact of landscape anthropization on the survival rates of 66 GPS-tagged adult Eurasian griffon vultures (Gyps fulvus) in two Spanish regions. Foraging in more anthropized areas resulted in a significantly higher individual mortality risk mainly due to collisions with vehicles, poisonings, electrocutions and fatalities with wind turbines. Mean yearly survival rates were estimated at 0.817 ± 0.043 SE and 0.968 ± 0.018 SE for individuals from the more and less anthropized regions, respectively. Additional research should investigate whether some vulture populations could be acting as sinks unnoticed due to metapopulation dynamics. From a broader point of view, our study shows that a straightforward Human Footprint was a useful index to predict the survival of top scavengers and can be highly applicable to planning large-scale conservation measures.
A recent press release (in Spanish) here