Publicação
Bio-ecology of the Egyptian mongoose (Herpestes ichneumon) in Portugal
| Resumo: | The Egyptian mongoose (Herpestes ichneumon Linnaeus, 1758) is a carnivore that in Europe is restricted to the Iberian Peninsula and whose distribution in Portugal was previously confined to the South of the Tagus River until the mid-1990's. During the last decades, this species has been expanding geographically, from inland to the coast and from South to North. Some populations of Egyptian mongoose are already found in the Atlantic biogeographical region, where they find new ecological, climate and habitat conditions. The Egyptian mongoose is negatively perceived by the hunting community who believes it to predate mostly on small game species with great economic interest, such as the European rabbit, the red-legged partridge and its eggs, and to generate multiple and numerous litters. However, these concerns lack scientific clarification. Ecological aspects of Egyptian mongoose are known mainly from scientific work carried out on the population of the Doñana region (Spain) or Israel. Studies on the ecology of the Portuguese populations of this carnivore are scarce or restricted to certain geographic areas. The ecology of the Egyptian mongoose on a biogeographic scale, covering different ecological and climatic patterns or human pressure is unknown and lacks comprehension and scientific evidence. This work aims to contribute to the knowledge of the fundamental, trophic and reproductive ecological aspects of the Egyptian mongoose, both in its historical distribution areas, and in the expansion and recently colonized areas. In this study, 678 mongooses were sampled from accidental road-kills (33), density correction actions and legal acts of hunting (645) in the territory of mainland Portugal. In this context, the main objectives of this study include: 1) description and analysis of biometric parameters; 2) determination and analysis of the factors that regulate immune competence and body condition; 3) identification of the main prey and evaluation of its trophic ecology, according to gender, age classes, seasons and regions, shaped by different environmental characteristics, climatic conditions and human pressures; 4) the identification of reproductive, pregnancy and lactation periods, determination of litter size and analysis of reproductive patterns. The results obtained indicate for the first time sexual dimorphism in body size in the Egyptian mongoose populations of the Portuguese territory, in which males are larger than females, in addition to clear biometric differences between regions. The reported variations are suggested to be regulated by sexual selection, food availability, human pressure and by different habitat use patterns. For the first time, the average weight and main body measurements of juvenile type I, type II and sub-adults were determined. Variations in immune competence were identified throughout the year, which was higher in males, justified by the reproductive behavior, parasitism, or diseases. A statistically significant relationship between immune competence and body condition was detected, which also differs between genders and ages due to trophic and reproductive ecology. Diet analysis indicates that small game species represent less than half of the consumed food spectrum. In this study the average sizes (3) (=2.75), range (1 a 4), and mode (3) of the litters were also determined. Additionally, the active periods of reproductive organs, pregnancy and lactation were identified, which are associated to the increasing photoperiod and to primary productivity, starting at the peak of winter and elapsing until the beginning of summer. Finally, we found male-specific conflicts in resource allocation between mating effort/parental investment and body condition, as well as with immune function, supporting the notion of an energetic trade-off and fitness cost associated with reproductive performance. With the information drawn from this research, we hope to shed light on mongoose’s bio-ecology and to create a framework for future research, either related to health or climate change. This work is also a contribution for the reassessment of the hunting status and improvement of the Egyptian mongoose management in Portugal. |
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| Autores principais: | Bandeira, Victor José |
| Assunto: | Dimorfismo sexual (Animais) Sacarrabos - Ecologia Biometria |
| Ano: | 2016 |
| País: | Portugal |
| Tipo de documento: | tese de doutoramento |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade de Aveiro |
| Idioma: | inglês |
| Origem: | RIA - Repositório Institucional da Universidade de Aveiro |
| Resumo: | The Egyptian mongoose (Herpestes ichneumon Linnaeus, 1758) is a carnivore that in Europe is restricted to the Iberian Peninsula and whose distribution in Portugal was previously confined to the South of the Tagus River until the mid-1990's. During the last decades, this species has been expanding geographically, from inland to the coast and from South to North. Some populations of Egyptian mongoose are already found in the Atlantic biogeographical region, where they find new ecological, climate and habitat conditions. The Egyptian mongoose is negatively perceived by the hunting community who believes it to predate mostly on small game species with great economic interest, such as the European rabbit, the red-legged partridge and its eggs, and to generate multiple and numerous litters. However, these concerns lack scientific clarification. Ecological aspects of Egyptian mongoose are known mainly from scientific work carried out on the population of the Doñana region (Spain) or Israel. Studies on the ecology of the Portuguese populations of this carnivore are scarce or restricted to certain geographic areas. The ecology of the Egyptian mongoose on a biogeographic scale, covering different ecological and climatic patterns or human pressure is unknown and lacks comprehension and scientific evidence. This work aims to contribute to the knowledge of the fundamental, trophic and reproductive ecological aspects of the Egyptian mongoose, both in its historical distribution areas, and in the expansion and recently colonized areas. In this study, 678 mongooses were sampled from accidental road-kills (33), density correction actions and legal acts of hunting (645) in the territory of mainland Portugal. In this context, the main objectives of this study include: 1) description and analysis of biometric parameters; 2) determination and analysis of the factors that regulate immune competence and body condition; 3) identification of the main prey and evaluation of its trophic ecology, according to gender, age classes, seasons and regions, shaped by different environmental characteristics, climatic conditions and human pressures; 4) the identification of reproductive, pregnancy and lactation periods, determination of litter size and analysis of reproductive patterns. The results obtained indicate for the first time sexual dimorphism in body size in the Egyptian mongoose populations of the Portuguese territory, in which males are larger than females, in addition to clear biometric differences between regions. The reported variations are suggested to be regulated by sexual selection, food availability, human pressure and by different habitat use patterns. For the first time, the average weight and main body measurements of juvenile type I, type II and sub-adults were determined. Variations in immune competence were identified throughout the year, which was higher in males, justified by the reproductive behavior, parasitism, or diseases. A statistically significant relationship between immune competence and body condition was detected, which also differs between genders and ages due to trophic and reproductive ecology. Diet analysis indicates that small game species represent less than half of the consumed food spectrum. In this study the average sizes (3) (=2.75), range (1 a 4), and mode (3) of the litters were also determined. Additionally, the active periods of reproductive organs, pregnancy and lactation were identified, which are associated to the increasing photoperiod and to primary productivity, starting at the peak of winter and elapsing until the beginning of summer. Finally, we found male-specific conflicts in resource allocation between mating effort/parental investment and body condition, as well as with immune function, supporting the notion of an energetic trade-off and fitness cost associated with reproductive performance. With the information drawn from this research, we hope to shed light on mongoose’s bio-ecology and to create a framework for future research, either related to health or climate change. This work is also a contribution for the reassessment of the hunting status and improvement of the Egyptian mongoose management in Portugal. |
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