Living on the Edge: Assessing the Extinction Risk of Critically Endangered Bonelli’s Eagle in Italy

Background: The population of Bonelli’s eagle (Aquila fasciata) has declined drastically throughout its European range due to habitat degradation and unnatural elevated mortality. There are less than 1500 breeding pairs accounted for in Europe, and the species is currently catalogued as Critically Endangered in Italy, where the 22 territories of Sicily, represent nearly 95% of the entire Italian population. However, despite national and European conservation concerns, the species currently lacks a specific conservation plan, and no previous attempts to estimate the risk of extinction have been made. Methodology/Principal Findings: We incorporated the most updated demographic information available to assess the extinction risk of endangered Bonelli’s eagle in Italy through a Population Viability Analysis. Using perturbation analyses (sensitivity and elasticity), and a combination of demographic data obtained from an assortment of independent methods, we evaluated which demographic parameters have more influence on the population’s fate. We also simulated different scenarios to explore the effects of possible management actions. Our results showed that under the current conditions, Bonelli’s eagle is expected to become extinct in Italy in less than 50 years. Stand-alone juvenile mortality was the most critical demographic parameter with the strongest influence on population persistence with respect to other demographic parameters. Measures aimed at either decreasing juvenile mortality, adult mortality or decreasing both juvenile and adult mortality resulted in equivalent net positive effects on population persistence (population growth rate l.1). In contrast, changes aimed at increasing breeding success had limited positive effects on demographic trends. Conclusions/Significance: Our PVA provides essential information to direct the decision-making process and exposes gaps in our previous knowledge. To ensure the long-term persistence of the species in Italy, measures are urgently needed to decrease both adult mortality due to poaching and juvenile mortality due to nest plundering, the top ranking mortality causes.PLL is supported by a “Juan de la Cierva” postdoctoral grant of the Spanish Ministry of Economy and Competitiveness (reference JCI-2011–09588)

A novel damage detection technique for laminated composite beams under the action of a moving load

The present paper investigates damage detection in laminated composite beams under the action of a moving load. A novel approach is introduced to present damage indices by utilizing the dynamic response of the beam. The equations of motion for the beam have been derived by considering in-plane and out-of-plane deformations, rotary inertia, and shear effects. To obtain the solution, the finite element method, in conjunction with the Newmark algorithm, has been employed. Three damage indices, namely the Displacement Variation Index (DVI), Velocity Variation Index (VVI), and Acceleration Variation Index (AVI) have been introduced. These indices are utilized to detect the location of damage based on the beam's displacement, velocity, and acceleration, respectively. Furthermore, the proposed approach enables to detect single and multiple damages at different severities, locations, and boundary conditions. Likewise, it is applicable to various velocities of moving forces and can effectively operate in both normal and noisy conditions. The results of this investigation demonstrate that the proposed damage indices are able to accurately detect damage along the entire length of the beam without prior knowledge of its healthy state. It is noteworthy that the acceleration-based index, among the indices pro-posed in this study, exhibits the highest efficiency in determining the precise location of the damage under operational conditions

Decoupling fracture modes in non-standard test specimens: state of the art

We call here as non-standard an interfacial fracture specimen that features an asymmetry w.r.t. the crack plane (e.g., bimaterial joint). Such specimens generally undergo mixed-mode (I/II) fracture even if they are loaded in pure mode (I or II). Aiming, however, to characterize the pure-mode fracture of them, several attempts have been made to decouple mode I and mode II. Ouyang et al. [1] focused on the bimaterial case. They stated that mode decoupling is achieved when the differential equation of the mode I (mode II) fracture is only governed by the interfacial normal (shear) stress and relative transverse (axial) displacement. A similar statement was recently made by Bennati et al. [2], who provided a more general decoupling condition covering the case where both adherents feature bending-extension coupling. The same topic was also investigated by Maimí et al. [3], who provided a different decoupling condition from that by Bennati et al. Wang et al.’s [4] “strain-based” decoupling condition is the same with that by Ouyang et al. based on an assumption (i.e., matching the axial strains of the two adherents) simpler than solving the mathematical problem. In parallel, individual authors sometimes adopt different decoupling criteria (e.g., matching the bending rigidities of the two adherents), usually without justifying their choice, though. The present work brings together and reviews the scattered—and sometimes overlapping—contributions, aiming to elucidate the confusion observed