Giacomo Tavecchia

Mediterranean Institute for Advanced Studies (IMEDEA) | IMEDEA · Animal Demography and Ecology Unit Department of Animal and Microbial Biodiversity

The Mediterranean lizard Podarcis lilfordi is an emblematic species of the Balearic Islands. The extensive phenotypic diversity among extant isolated populations makes the species a great insular model system for eco-evolutionary studies, as well as a challenging target for conservation management plans. Here we report the first high quality chromo...

Animal conservation relies on assessing the distribution and habitat use of species, but for endangered/elusive animals this can prove difficult. The Monk Seal, Monachus monachus, is one of the world's most endangered species of pinniped, and the only one endemic to the Mediterranean Sea. During recent decades, direct observations have been few and...

Compared to other animal movements, prospecting by adult individuals for a future breeding site is commonly overlooked. Prospecting influences the decision of where to breed and has consequences on fitness and lifetime reproductive success. By analysing movements of 31 satellite-and GPS-tracked gull and tern populations belonging to 14 species in E...

Background Integrative studies of animals and associated microbial assemblages ( i.e. , the holobiont) are rapidly changing our perspectives on organismal ecology and evolution. Insular vertebrates provide ideal natural systems to understand patterns of host-gut microbiota coevolution, the resilience and plasticity these microbial communities over...

Small vertebrates on islands are expected to attain a larger body size, and a greater survival than their mainland counterparts. Comparative studies have questioned whether lizards exhibit this set of adaptations, referred to as the ‘island syndrome’. We collected data on 730 individuals the endemic Lilford's lizard (Podarcis lilfordi) throughout a...

Climate change may affect life on Earth in multiple ways. Whereas some populations may encounter detrimental conditions that cause extirpations, those occupying cooler thermal limits of a range may benefit by expanding. For sea turtles, egg maturation in the female oviduct and nest incubation are temperature-dependent and vulnerable to climate chan...

Synchrony can have important consequences for long-term metapopulations persistence, community dynamics and ecosystems functioning. While the causes and consequences of intra-specific synchrony on population size and demographic rates have received considerable attention only a few factors that may affect inter-specific synchrony have been describe...

Climate change is increasing the frequency of extreme events, such as droughts or hurricanes, with substantial impacts on human and wildlife communities. Extreme events can affect individuals through two pathways: by altering the fitness of adults encountering a current extreme, and by affecting the development of individuals born during a natal ex...

The food available in open-air landfills, one of the most common Predictable Anthropogenic Food Subsidies (PAFS), can have a profound impact on animal biodiversity. Understanding how and to what extent PAFS affect wildlife is crucial for a sustainable management of resources. Most large gulls behave as opportunistic foragers and constitute a good a...

Integrative studies of animals and associated microbial assemblages (i.e., the holobiont) are rapidly changing our perspectives on organismal ecology and evolution. Islands provide ideal natural systems to understand the biogeographic patterns that shape these symbiotic associations, their resilience and plasticity over temporal and spatial scales,...

Recently isolated populations offer a good biological model to infer the evolutionary forces responsible for the current divergences across populations. We coupled genetic, morphometric, ecological, and demographic analyses from three island populations of the endemic Balearic Wall Lizard, Podarcis lilfordi, (Balearic archipelago, Spain) to infer t...

Tres islotes situados frente a las costas de Mallorca albergan otras tantas poblaciones de lagartija balear, que han evolucionado de forma independiente debido al aislamiento, a su estructura demográfica y a ligeras variaciones en el medio físico.

Survival analyses are a key tool for demographers, ecologists, and evolutionary biologists. This chapter presents the most common methods and illustrates their use for species across the Tree of Life. It discusses the challenges associated with various types of survival data, how to model species with a complex life cycle, and includes the impact o...

The increase in the average air temperature due to global warming has produced an early onset of the reproduction in many migratory birds of the Paleartic region. According to the ‘mismatch hypothesis’ this response can lead to a decrease in the breeding output when the conditions that trigger the departure from the wintering areas do not match the...

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...

Large, long‐lived species with slow life histories and protracted pre‐breeding stages are particularly susceptible to declines and extinction, often for unknown causes. Here, we show how demographic modelling of a medium‐sized raptor, the Red kite Milvus milvus, can aid to re‐focus conservation research and attention on the most likely mechanisms d...

Factores que influyen en la dinámica poblacio-nal : 1. Condiciones climáticas y disponibilidad tróficas en zonas de invernada y reproducción: relación de la supervivencia con índices climáticos (SOI,NAO) (5). 2. Bycatch. Gran riesgo en zonas de alimentación (6 ,7). 3. Otros factores: Mareas rojas, vertidos, plásti-cos, contaminación lumínica, etc,...

Identifying important foraging areas is fundamental to detecting the demographic drivers of a species and ultimately to plan conservation measures. For some species, such as small pelagic seabirds, foraging grounds are difficult to locate and remain largely unknown. We used miniaturised GPS devices (∼0.95g) to study foraging movements of Mediterran...

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...

In many species with continuous growth, body size is an important driver of life-history tactics and its relative importance is thought to reflect the spatio-temporal variability of selective pressures. We developed a deterministic size-dependent integral projection model (IPM) for three insular neighbouring lizard populations with contrasting adul...

the annual cycle of most animals is structured into discrete stages, such as breeding, migration and dispersal. While there is growing appreciation of the importance of different stages of an organism's annual cycle for its fitness and population dynamics, almost nothing is known about if and how such seasonal effects can change through a species l...

The annual cycle of most animals is structured into discrete stages, such as breeding, migration and dispersal. While there is growing appreciation of the importance of different stages of an organism’s annual cycle for its fitness and population dynamics, almost nothing is known about if and how such seasonal effects can change through a species l...

Background: Poaching is a prominent source of ‘hidden hurdles’, cryptic impacts of human activities that may hinder the conservation of animal populations. Estimating poaching mortality is challenging, as the evidence for illegal killing is not outwardly obvious. Using resighting and recovery data collected on 141 marked red deer Cervus elaphus wit...

Despite it is widely accepted that intra-population variation is fundamental to ecological and evolutionary processes, this level of information has only recently been included into network analysis of species/population interactions. When done it has revealed non-random patterns in the distribution of trophic resources. Nestedness in resource use...

After a period of overfocus on the establishment of reserves, attention is increasingly being devoted to the capability of protected areas to maintain viable populations of endangered species. Here, we examined the trends and reproduction of the red kite Milvus milvus, a highly endangered raptor near-endemic to Europe, to illustrate the dual benefi...

The relative role of density‐dependent and density‐independent variation in vital rates and population size remains largely unsolved. Despite its importance to the theory and application of population ecology, and to conservation biology, quantifying the role and strength of density dependence is particularly challenging. We present a hierarchical...

The management of game species relies on robust estimates of hunting-related mortality. A relative measure of this mortality can be obtained by comparing survival estimates of animals across similar areas with different hunting pressures. We conducted live recapture-dead recovery analyses on wintering Eurasian Woodcocks Scolopax rusticola (hereinaf...

Discards from fisheries are the most important predictable anthropogenic food subsidies (PAFS) that are being incorporated into marine ecosystems. Changes on their availability and predictability can help us to understand the role that food availability (i.e. an important indicator of the carrying capacity) plays at different ecological levels, fro...

Supplementary Material

During the last few decades, many breeding waders have been declining worldwide, probably due to the reduction of suitable coastal habitats. Diagnosis of population parameters has become increasingly important for the conservation of waders. We used capture-recapture information of 214 adult Kentish Plovers Charadrius alexandrinus, marked between 1...

Estimates of survival probabilities in natural populations can be obtained through capture–mark–recapture (CMR) models. However, when capture sessions are unevenly spaced, age–dependent models can lead to erroneous estimates of survival when individuals change age class during the time interval between two capture occasions. We propose a solution t...

Recent European policies on the ban of fishing discards and the closure of open-air landfills are expected to reduce predictable and abundant food resources for generalist seabirds. In order to forecast the consequences of this reduction on seabird breeding investment it is important to understand whether diverse anthropogenic foraging resources ac...

Amphibian populations are declining worldwide but for many taxa, robust estimates of demographic parameters to assess population state or trend are scarce or absent. We provide robust estimates of adult apparent survival of the endemic Mallorcan midwife toad Alytes muletensis using individual capture-recapture data collected over 4 yr in a 60m2 cis...

Backgrounds Aedes albopictus (Diptera; Culicidae) is a highly invasive mosquito species and a competent vector of several arboviral diseases that have spread rapidly throughout the world. Prevalence and patterns of dispersal of the mosquito are of central importance for an effective control of the species. We used site-occupancy models accounting f...

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 spe...

The number of nesting leatherback turtles (Dermochelys coriacea) in the eastern Pacific Ocean has declined dramatically since the late 1980s. This decline has been attributed to egg poaching and interactions with fisheries. However, it is not clear how much of the decline should also be ascribed to variability in the physical characteristics of the...

Local recruitment and immigration play an important part in the dynamics and growth of animal populations. However, their estimation and incorporation into open populations models is, in most cases, problematic. We studied factors affecting the growth of a recently established colony of Eurasian spoonbill (Platalea leucorodia) and assessed the cont...

Current climatic changes have increased the need to forecast population responses to climate variability. A common approach to address this question is through models that project current population state using the functional relationship between demographic rates and climatic variables. We argue that this approach can lead to erroneous conclusions...

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 impac...

We investigated the sequence of environmental and biological processes driving the reproductive phenology and performance of the storm petrel (Hydrobates pelagicus) in the Western Mediterranean. The enhanced light and nutrient availability at the onset of water stratification (late winter/early spring) resulted in the annual consecutive peaks of ph...

The body growth rate in small reptiles is modulated by per-capita food resources and recent evidences 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. We used...

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 bias...

In evolutionary and ecological studies, demographic parameters are commonly derived from detailed information collected on a limited number of individuals or in a confined sector of the breeding area. This partial monitoring is expected to underestimate survival and recruitment processes because individuals marked in a monitored location may move t...

Temporal changes in adult sex ratio of animal populations might be due to differences in movements, survival or detection probabilities. We used data from an intensive capture–mark–recapture study of 720 lizards at the islet of Aire (Balearic Islands, Spain) to investigate the demographic mechanisms underlying the spring uneven sex ratio. We simult...

The deployment of electronic devices on animals is rapidly expanding and producing leapfrog advances in ecological knowledge. Even though their effects on the ecology and behaviour of the marked subjects are potentially important, <10% of the studies are accompanied by an evaluation of impact, and comprehensive, long-term assessments have been few....

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The control of overabundant vertebrates is often problematic. Much work has focused on population-level responses and overabundance due to anthropogenic subsidies. However, far less work has been directed at investigating responses following the removal of subsidies. We investigate the consequences of two consecutive perturbations-closure of a land...

Atmosphere-Ocean General Circulation Models (AOGCMs) predict changes in the sea ice environment and in atmospheric precipitations over larger areas of Antarctica. These changes are expected to affect the population dynamics of seabirds and marine mammals, but the extent of this influence is not clear. We investigated the future population trajector...

Some opportunistic vertebrates exploit, and may largely rely upon, food generated by human activities. Better understanding the influence of this additional anthropogenic food on species’ ecology would inform sustainable waste management. In the Balearic Archipelago of Spain, closure of an open-air landfill site provided an experimental setting to...

Some opportunistic vertebrates exploit, and may largely rely upon, food generated by human activities. Better understanding the influence of this additional anthropogenic food on species’ ecology would inform sustainable waste management. In the Balearic Archipelago of Spain, closure of an open-air landfill site provided an experimental setting to...

1.With ongoing climate change, many species are expected to shift their spatial and temporal distributions. To document changes in species distribution and phenology, detection/non-detection data have proven very useful. Occupancy models provide a robust way to analyze such data, but inference is usually focused on species spatial distribution, not...

The control of overabundant vertebrates is often problematic. Much work has focused on population-level responses and overabundance due to anthropogenic subsidies. However, far less work has been directed at investigating responses following the removal of subsidies. We investigate the consequences of two consecutive perturbations, the closure of a...

Billions of organisms, from bacteria to humans, migrate each year and research on their migration biology is expanding rapidly through ever more sophisticated remote sensing technologies. However, little is known about how migratory performance develops through life for any organism. To date, age variation has been almost systematically simplified...

Following the advent of MCMC engines Bayesian hierarchical models are becoming increasingly common for modelling ecological data. However, the great enthusiasm for model fitting has not yet encompassed the selection of competing models, despite its fundamental role in the inferential process. This contribution is intended as a starting guide for pr...

1.Estimating rates of population change is essential to achieving theoretical and applied goals in population ecology, and the Pradel (1996) temporal symmetry method permits direct estimation and modelling of the growth rate of open populations, using capture-recapture data from marked animals.2.We present a Bayesian formulation of the Pradel appro...