Situation of the Egyptian mongoose (Herpestes ichneumon) in Castilla-La Mancha, effects on its prey and social perception
- Autores: Esther Descalzo Sánchez
- Directores de la Tesis: Pablo Ferreras (dir. tes.), Miguel Delibes Mateos (codir. tes.)
- Lectura: En la Universidad de Castilla-La Mancha ( España ) en 2022
- Idioma: inglés
- Tribunal Calificador de la Tesis: Francisco Palomares Fernández (presid.), Beatriz Arroyo López (secret.), Yolanda Melero Cavero (voc.)
- Programa de doctorado: Programa de Doctorado en Ciencias Agrarias y Ambientales por la Universidad de Castilla-La Mancha
- Materias:
- Enlaces
- Tesis en acceso abierto en: RUIdeRA
- Resumen
Some factors as habitat, land use and climatic changes have produced the global decline of carnivore top predators involving an increase of some mesocarnivore species. Part of the human population is concerned about this increase mainly because of negative impact on species with economic value (livestock and game species), resulting in major human-wildlife conflicts. One of such mesopredators is the Egyptian mongoose (Herpestes ichneumon), the target species of this doctoral thesis. Some collectives (hunters, landowners and farmers) complain about the abundance and spread of this species, which they consider as a pest because its alleged impact on small game populations. However, there is a lack of scientific knowledge about this mongoose in its distribution limit in Europe, which prevents the reduction of the above-mentioned conflicts involving the mongoose. The main objective of this PhD thesis is to update the scientific knowledge about the ecology of the Egyptian mongoose in its Iberian range edge.
This doctoral thesis is focused on the current situation of the Egyptian mongoose in its European distribution limit. Monitoring the distribution of this mongoose requires knowing and assessing the most efficient methods for its detection. Firstly, the success rate of scat identification of the Egyptian mongoose was assessed and compared with that of the red fox (Vulpes vulpes) (chapter I). Searching for the mongoose characteristic hairs in the laboratory increased the rate of correct scat identification of this mongoose from 75.6% in field identification to 93% after lab identification. This methodology represents an alternative to molecular analyses which require high DNA and analyses quality and the collection of fresh scats which is economically very costly. In addition, this thesis results show that Egyptian mongoose scats are generally found in places different to those where those of red foxes are found (i.e. the edge of the scrubland and riverbanks vs the edge of trails). Occupancy models were used to estimate the detection probability of the mongoose obtained with different survey methods (sign surveys, hair-traps and camera-traps) in four study areas (chapter II). Camara-trapping was the most efficient single method followed by sign surveys. Nevertheless, the combination of camera-traps, transects on foot looking for signs and hair-traps increases the detection probability of this mongoose and improves the estimates accuracy.
To update the distribution of this carnivore, an on-line questionnaire survey was conducted to environmental rangers from Castilla-La Mancha (CLM) and records from researchers and technicians were also collected (chapter III). Data gathered in this study showed that the Egyptian mongoose currently is present in almost all Portugal and the Southwest of Spain, occupying almost all Extremadura, Southwest of Andalucía, West of CLM and some isolated areas in North and East of Spain. Another questionnaire to hunters from CLM provided additional mongoose records whose reliability was assessed through a comparison with those records provided by rangers (professionals). The great congruence between hunters and professionals suggests that the formers are a reliable source of information on the distribution of non-game wildlife species, and thus that their engagement in citizen science initiatives is highly recommended (chapter IV).
Through an approximation based on biogeographic models, information on mongoose occurrence collected in the questionnaire survey to rangers and environmental variables, the current and future potential distributions of the Egyptian mongoose in CLM were modelled (chapter V). The current distribution model showed a potential distribution mainly concentrated on Toledo and Ciudad Real provinces, where intermediate-high favourability values were prevalent. According to the ecological model in the South and West of Albacete province showed favourable environmental conditions for the species occurrence in the future. This study proved the reliability of these models to assess the current and potential distribution of this mongoose and other wildlife species. Through the combination of occupancy models and records of the Egyptian mongoose provided by rangers in three different periods, the factors related to the occurrence and expansion of this mongoose were assessed (chapter VI). The results confirm and quantify the range expansion of this predator in central Spain in the last two decades. The average annual temperature and the length of waterways were related to the probability of mongoose occupancy in different periods. However, its range expansion was apparently not limited by environmental factors because no environmental covariate was associated with the colonization probability.
The analyses of scats and stomach contents conducted in this thesis revealed that the Egyptian mongoose in its distribution edge has a diverse diet (chapter VII), being the European rabbit (Oryctolagus cuniculus) the most consumed prey overall. Nevertheless, in areas with low rabbit densities the mongoose replaces rabbits with other available prey, such as reptiles and small mammals. Its diet also varies according to the season, being more diverse in summer, when the diversity of available foods is highest. The predation impact of the Egyptian mongoose on rabbits and red-legged partridges (Alectoris rufa) was assessed by estimating the mongoose diet and the densities of the predator and its prey in three areas within CLM (chapter VIII). The estimated mongoose densities were close in the three study areas (0.40-0.57 mongooses/km2), despite the large variations in prey availability (e.g. 8.7-369.5 rabbits/ km2) and the presence in one of the areas of Iberian lynx (Lynx pardinus), the top predator that could limit mongoose populations. The impact on rabbits was low (<12% of the rabbit population) in the study area with the highest rabbit density, whereas it was high (35%-66%) in the study areas with lower rabbit density. The predation impact on the red-legged partridge was apparently low since this prey was only found in two Egyptian mongoose scats. However, this result must be taken with caution because of very low partridge densities in the three study areas.
Finally, the knowledge and perception of different groups (i.e. hunters, rural and urban residents in CLM) on the Egyptian mongoose were assessed through online questionnaires (chapter IX). Most hunters recognised the mongoose, but unexpectedly most of the rural population were unaware of the species in spite of being potentially in contact with nature. Most urban people were unaware of the species, as expected from their reduced contact with nature. The Potential Conflict Index (PCI2) was used to assess the variations in the perceptions about the mongoose between respondents. According to the PCI2 values, hunters generally agreed with the negative impacts of the Egyptian mongoose on the ecosystems and human livelihood (e.g. impact of predation on small-game and protected species). Opinions of rural people regarding mongoose detrimental effects were more neutral, and those of urban people were mainly in disagreement with such statements. The opposite pattern was detected for potential benefits associated with the occurrence of the mongoose, with hunters being those most in disagreement and urban people agreeing mostly. Furthermore, there were differences in the perception of both beneficial and detrimental effects of the species between the knowledgeable and unknowledgeable respondents. Knowing the perception and knowledge of human population about wildlife is a key piece of information to be considered in management and conservation programs of wildlife.
This thesis contributes with new data about the current situation of the Egyptian mongoose in its range edge of distribution. The selection of the most efficient methods to detect this mongoose allowed to update the current distribution of the Egyptian mongoose in Spain. Its distribution provided the information necessary to assess its recent expansion in Castilla-La Mancha and the factors that determined it, and the potential areas that this mongoose will likely occupy in the future according to the environmental factors. Besides, this carnivore is a generalist predator, therefore its expansion will not be limited by the kind of food. The current expansion of the Egyptian mongoose in Spain will generate more conflicts with human population due to the social perception about the carnivore species. Hunters usually consider that the Egyptian mongoose reduces the population of small game species, but the predation impact estimates showed that the effect of Egyptian mongoose predation on rabbit demography apparently is not strong. In conclusion, a continuous monitoring of the Egyptian mongoose in Spain will allow to carry out management or conservation plans according to the requirements of the mongoose situation.
