Andrés Giménez

Evaluation of Local Ecological Knowledge as a Method for Collecting Extensive Data on Animal Abundance

The use of local ecological knowledge (LEK) has been advocated for biodiversity monitoring and management. To date, however, it has been underused in studying wild populations of animals and, particularly, in obtaining quantitative abundance estimates. We evaluated LEK as a tool for collecting extensive data on local animal abundance and population trends. We interviewed shepherds in southeastern Spain, asking them to estimate the local abundance of the terrestrial tortoise Testudo graeca. We quantified reliability of abundance estimates derived from interviews by comparing them with those obtained from standard field-sampling protocols (distance sampling). We also explored the complementarity of these 2 approaches. LEK provided high-quality and low-cost information about both distribution and abundance of T. graeca. Interviews with shepherds yielded abundance estimates in a much wider range than linear transects, which only detected the species in the upper two-thirds of its abundance range. Abundance estimates from both methodologies showed a close relationship. Analysis of confidence intervals indicated local knowledge could be used to estimate mean local abundances and to detect mean population trends. A cost analysis determined that the information derived from LEK was 100 times cheaper than that obtained through linear-transect surveys. Our results should further the use of LEK as a standard tool for sampling the quantitative abundance of a great variety of taxa, particularly when population densities are low and traditional sampling methods are expensive or difficult to implement.

Breeding waterbirds in relation to artificial pond attributes: implications for the design of irrigation facilities

The growth of inter-basin water transfers and the development of new irrigation facilities in southeastern Spain are responsible for a variety of ecological impacts. In spite of this, the construction of artificial ponds to keep water for intensive agriculture may also provide new habitats for breeding waterbirds. We counted waterbirds during the breeding season in artificial ponds that had been built up using different materials and measured their abiotic and biotic attributes. We found that ponds were used as breeding and foraging habitat by 22 different waterbird species and breeding numbers of a few of them seemed to be larger in these artificial facilities than in nearby natural and semi-natural wetlands. Abundance and richness of breeding waterbirds was influenced by construction materials. Ponds constructed with low density polyethylene and covered with sand and stones held more species and their numbers were higher than those constructed with other plastic materials. The presence of emergent and submerged vegetation as well as abiotic attributes, such as pond size, accounted for most of the deviance when modelling richness and species abundance.

What is wrong with current translocations? A review and a decision-making proposal

Should a species be translocated? Uncertainty regarding the necessity and feasibility of many translocations complicates answering this question. Here, we review translocation projects, both published and unpublished. Our results indicate that most projects (1) addressed fewer than half of the basic criteria established for translocations and (2) were either unjustifiable from a conservation perspective or inadequately designed to guarantee success or preclude negative consequences. We propose a hierarchical decision-making system – an explicit method that integrates existing guidelines, thereby covering a key gap in conservation science – to reduce ambiguity when deciding whether to implement a given translocation project. This method will improve the likelihood of success in translocation projects and contribute to the efficient use of the limited resources available for these conservation efforts.

Habitat Selection by the Spur-thighed Tortoise Testudo graeca in a Multisuccessional Landscape: Implications for Habitat Management

As a result of human activities, natural Mediterranean landscapes (including agro-ecosystems) are characterised by a mosaic-like structure with habitat-patches at different successional stages. These systems have high biodiversity levels and are home to a large number of species protected by European laws whose habitats should be adequately managed. In the present work, we study habitat use from an applied point of view in the spur-thighed tortoise Testudo graeca, an endangered reptile present in semi-arid Mediterranean agro-ecosystems. Results show that, at a landscape scale, the species selects simplified vegetation structures and includes in its home range re-colonisation shrubland and small non-irrigated fields. Within the home range, habitat selection patterns vary and areas with higher vegetation cover and complexity are selected. Detected patterns are discussed in terms of the ecological requirements of the species and with a hierarchical view of resources and conditions. The implications of our findings for habitat management aimed at the conservation of the species are also discussed.

Surfing in tortoises? Empirical signs of genetic structuring owing to range expansion

Much of our current knowledge about the genetic dynamics in range expansions originates from models, simulations and microcosm experiments that need to be corroborated by field data. Here, we report a neutral genetic pattern that matches the predictions of the genetic surfing theory. Genetic surfing occurs when repeated founding events and genetic drift act on the wave of advance of an expanding population, promoting strong spatial structure. In the range expansion of the tortoise Testudo graeca from North Africa to southeastern Spain, we found several genetic signatures consistent with surfing: a decrease of genetic diversity with distance from the initial founder area, clinal patterns in allele frequencies, rare African alleles which have become common at distal sites in the Spanish range, and stronger spatial differentiation in the expanded range than in the original one. Our results provide support for the theory that genetic drift can be an important force in shaping the genetic structure of expanding populations.

Molecular Detection of Hemolivia (Apicomplexa: Haemogregarinidae) from Ticks of North African Testudo graeca (Testudines: Testudinidae) and an Estimation of Their Phylogenetic Relationships Using 18S rRNA Sequences

ABSTRACT: Hemolivia mauritanica is an apicomplexan parasite infecting the tortoises Testudo graeca and Testudo marginata as the intermediate vertebrate host, and the tick Hyalomma aegyptium as the definitive invertebrate host. Here, we used molecular techniques to detect an apparent H. mauritanica in the ticks H. aegyptium, attached to Testudo graeca from North Africa. Sequences from 18S rRNA were used to place the new sequences, and others retrieved from GenBank, in a phylogenetic framework. A single Hemolivia haplotype was recovered from 16 ticks. Prevalence was estimated at 22.6% of hosts having ticks infected with H. mauritanica.

Distribution of Testudo graeca in the western Mediterranean according to climatic factors

Despite being one of the most charismatic elements of the Mediterranean Basin fauna and its threatened status, the western Mediterranean range of Testudo graeca is at present very poorly known. The present work provides the most detailed geographical and ecological description for the North African clade of T. graeca so far. We gathered 283 occurrence data of T. graeca in North Africa and modelled the distribution by means of presence-only distribution modelling tools. The obtained model was then projected to southern Europe in order to explore whether the environmental characteristics of European populations fall into the predicted niche of the species in North Africa. T. graeca showed a wide environmental range in North Africa. Presence localities ranged from the sea level to 2090 m of altitude and from 116 to 1093 mm of annual precipitation. The presence-only model indicates that distribution in North Africa is mainly related to rainfall, specifically rainfall values in the wettest and coldest quarter of the year. The distribution model showed a range of ca. 1 000 000 km 2 . The projection of the model to southern Europe showed that the southern Iberian and Balkan Peninsulas, as well as most Mediterranean islands, present climatic conditions within those found in the range of the species in North Africa.

A qualitative examination of the social practices and representations towards a species of endangered tortoise

Context Understanding how people view, think and talk about wildlife and the link between wildlife and human behaviour are important for wildlife management to be effective. In this paper, we used the notion of social representations to understand people’s behaviour towards wildlife. We qualitatively studied social representations relating to the keeping in captivity of the endangered tortoise Testudo graeca in south-east Spain. Aims The aims were to elucidate social representations towards the spur-thighed tortoise, and to understand the link between social representation and the motivations for collecting and keeping tortoises in captivity. We discuss the conservation implications of social representation towards this tortoise species and provide some management recommendations. Methods We carried out 13 in-depth interviews with rural–agrarian, urban and neorural dwellers who kept tortoises in captivity to elucidate social representations towards the spur-thighed tortoise and to understand the link between social representation and the motivations for collecting and keeping tortoises. Key results The discourse analysis shows that the social representations of this tortoise as a tameable animal, pet and safeguarded animal co-exist in south-east Spain. Conclusions The fact that the social reality in south-east Spain has changed from a social–agrarian society to an urban and neorural society seems to explain these social representations. The conservationist discourse espoused by some respondents partly explains why the habit of keeping tortoises in captivity has prevailed despite social changes in recent decades and this activity being prohibited since the 1970s. Implications Our findings reveal the utility of the social representation notion in understanding the social dimensions of wildlife conservation and its applicability to wildlife management.

Understanding the decline and resilience loss of a long-lived social-ecological system: insights from system dynamics

Collapse of social-ecological systems (SESs) is a common process in human history. Depletion of natural resources, scarcity of human capital, or both, is/are common pathways toward collapse. We use the system dynamics approach to better understand specific problems of small-scale, long-lived SESs. We present a qualitative (or conceptual) model using the conceptualization process of the system dynamics approach to study the dynamics of an oasis in Mexico that has witnessed a dramatic transition to decline in recent decades. We used indepth interviews, participant observation, expert opinions, and official statistical data sets to define the boundaries, and structure in a causal loop diagram of our studied system. We described historical trends and showed the reference mode for the main system variables (observed data), and analyzed the expected system behavior according to the system structure. We identified the main drivers that changed the system structure, as well as structural changes, and the effects of these changes on the dynamics, resilience, and vulnerability of this SES. We found that the tendency of this SES toward collapse was triggered by exogenous factors (growth of modern agriculture in nearby valleys, and socio-political relocation), and was maintained by an endogenous structure. These structural changes weakened the resilience of this SES. One of these changes resulted in a long-term maladaptation of the SES, which increased its vulnerability to frequent system disturbances (hurricanes and droughts). The conceptual model developed provides an in-depth qualitative description of the system, with an important amount of qualitative and quantitative information, to establish the structural hypothesis of the observed behavior. Using this qualitative model, the next research steps are to develop a quantitative model to test the qualitative theories, and to explore future scenarios of system resilience for decision-making processes to improve local conditions and restore the well-functioning of the system.

Differences in helminth infections between captive and wild spur-thighed tortoises Testudo graeca in southern Spain: A potential risk of reintroductions of this species

Although the spur-thighed tortoise, Testudo graeca, is one of the most widely distributed species of tortoises, its natural populations are threatened through its whole range. Particularly at south-eastern Spain, the species is mainly threatened by habitat destruction and over-collection, given that this chelonian has been traditionally considered an appreciate pet. As south-eastern Spanish wildlife recovery centers shelter hundreds of captive animals mainly coming from illegal trade or captive-bred, there is a strong debate about what to do with these animals: maintaining them in captivity all along their lives or reintroducing them to wildlife. It is well known that the reintroduction of captive animals supposes a risk for the wild population due to the uncertainty of their genetic origin and to the possible spread of infectious diseases. However, despite the increasing evidence that infectious agents are a potential health hazard for wildlife, little is known about the risk that introduced parasites could suppose for the wild populations of spur-thighed tortoise. The present study investigates for the first time the presence of helminth eggs and worms in faeces from 107 wild and captive individuals collected from mid-March to mid-June 2010, and relates the findings to different environmental and host variables. Sixteen oxyurid species and the ascarid Angusticaecum holopterum were identified. This last nematode and the oxyurid species Tachygonetria palearticus and T. seurati had not been reported in Spanish wild T. graeca previously. The prevalence of oxyurid eggs and worms were 94% and 70%, respectively; while, ascarid eggs and worms were found in 26% and 5% of tortoises, respectively. Ascarid infections affected mostly captive animals and were associated to caparace deformities and symptoms of upper respiratory tract disease (p<0.05). Oxyurid infections were not associated to negative health traits and prevalence increased with age. In free-living tortoises, the distribution of pharingodonid genera also varied according to habitat; moreover, T. longicollis, T. pusilla, T. conica, T. robusta and Mehdiella stylosa where significantly more frequent in wild compared to captive tortoises (p<0.05). Study results highlight important differences in the nematode fauna of captive and free-living tortoises and questions one more time if the reintroductions of captive animals suppose a risk for the wild population since the former ones can harbor and distribute among free populations pathogens like ascarid nematodes.