Endogenous and exogenous constraints in the population changes of wild boar (sus scrofa Linnaeus, 1758)

The population dynamics of wild boar (Sus scrofa) was studied in a time series over 26 years using data from the Regional Hunting Reserve of Somiedo (northern Spain). This population is controlled by a complex negative feedback system that acts with one (main) and two (secondary) years of delay (lags). The primary feedback might be explained by intraspecific competition for food resulting from fluctuations in mast production (acorns and beech), and the secondary feedback might be explained by the influence of weather conditions or the delay of a cohort to reach reproductive status. We used a stochastic model that takes environmental variability into consideration when testing the demographical analysis that’s obtains simulations from real data

The interaction of Sika deer (Cervus nippon Temminck 1838) with lowland heath mosaics.

Sika deer (Cervus nippon) has become an invasive species in many parts of the world. In the south of England large populations appear to be concentrated in landscapes comprising of mosaics of lowland heath, woodlands and grassland. Despite the association between the distribution of Sika deer and that of lowland heath, little is known regarding the extent to which Sika deer utilize lowland heath and their impacts on its plant and animal communities. The aim of this thesis was to investigate the ecological interaction of Sika deer with lowland heath set in a mosaic of other habitats. Specifically, the main three objectives of this thesis were: i) to investigate the different ecological factors affecting the distribution and habitat use by Sika deer; iii) to explore consistency in Sika deer habitat associations as a potential tool to predict the distribution and abundance ofSika deer; iii) to investigate the ecological impacts of the usage of areas of lowland heath by Sika deer upon plant and animal communities oflowland heath. Results showed that Sika deer distribution and habitat use are affected by the availability of habitats, landscape structure and human disturbance at both the landscape and home range scale (i.e. few hundred of hectares and few dozens of hectares respectively). At the landscape scale, Sika deer seemed to use the requirement for safe access to pastures as the main criteria for their habitat selection. At the home range scale, the criteria of choice in the use of resources by Sika deer seemed to be related to a requirement for an appropriate balance of food and cover as the selection of pastures and cover were inversely related to their availability. However, human disturbance, as a form of perceived risk, was also a limiting factor of habitat use at the home range scale. Consistencies in the habitat selection by Sika deer at the landscape scale between areas with similar landscape were detected, which could potentially be used to develop models to predict the distribution and abundance of Sika deer and their subsequent impacts in areas of lowland heath. This study has found a different response of plant and animal communities between dry and wet heath to levels in usage of areas of heath by Sika deer. The existence of a threshold in the local density of Sika deer on areas of heath above which dry lowland heath showed signs of decline in quality has also been identified

The interaction of Sika deer (Cervus nippon Temminck 1838) with lowland heath mosaics

Sika deer (Cervus nippon) has become an invasive species in many parts of the world. In the south of England large populations appear to be concentrated in landscapes comprising of mosaics of lowland heath, woodlands and grassland. Despite the association between the distribution of Sika deer and that of lowland heath, little is known regarding the extent to which Sika deer utilize lowland heath and their impacts on its plant and animal communities. The aim of this thesis was to investigate the ecological interaction of Sika deer with lowland heath set in a mosaic of other habitats. Specifically, the main three objectives of this thesis were: i) to investigate the different ecological factors affecting the distribution and habitat use by Sika deer; iii) to explore consistency in Sika deer habitat associations as a potential tool to predict the distribution and abundance ofSika deer; iii) to investigate the ecological impacts of the usage of areas of lowland heath by Sika deer upon plant and animal communities oflowland heath. Results showed that Sika deer distribution and habitat use are affected by the availability of habitats, landscape structure and human disturbance at both the landscape and home range scale (i.e. few hundred of hectares and few dozens of hectares respectively). At the landscape scale, Sika deer seemed to use the requirement for safe access to pastures as the main criteria for their habitat selection. At the home range scale, the criteria of choice in the use of resources by Sika deer seemed to be related to a requirement for an appropriate balance of food and cover as the selection of pastures and cover were inversely related to their availability. However, human disturbance, as a form of perceived risk, was also a limiting factor of habitat use at the home range scale. Consistencies in the habitat selection by Sika deer at the landscape scale between areas with similar landscape were detected, which could potentially be used to develop models to predict the distribution and abundance of Sika deer and their subsequent impacts in areas of lowland heath. This study has found a different response of plant and animal communities between dry and wet heath to levels in usage of areas of heath by Sika deer. The existence of a threshold in the local density of Sika deer on areas of heath above which dry lowland heath showed signs of decline in quality has also been identified.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Heathland creation on improved grassland using sulphur: is there a conflict between optimal application rates for plant and animal communities?

We examined the effectiveness of using elemental sulphur (a soil acidifier) as a method for creating heathland on improved pasture. We determined i) optimal rate of sulphur application to control mesotrophic grasses ii) if invertebrates avoid areas of sulphur application. Results indicated that optimal sulphur application attracted invertebrates

Distribución y Aspectos Poblacionales del Lobo Ibérico en la Provincia de Ourense / Distribution and Population Aspects of the Iberian Wolf in the Province of Ourense, Spain

Para determinar el área de distribución del lobo en la provincia de Ourense (noroeste de España) se realizaron prospecciones de campo consistentes en itinerarios de muestreo para localizar indicios y se enviaron cuestionarios a los Agentes del Servicio de Conservación de la Naturaleza de la Xunta de Galicia y a las Sociedades de Cazadores del área de estudio. Los resultados se registraron sobre cuadrículas U.T.M. 10x10 Km. Se constata presencia del lobo en el 79,2% de las cuadrículas estudiadas, estimando el área de distribución en la provincia en 6.400 km2. Para la localización de los grupos familiares inicialmente se prospectó el territorio a nivel de cuadrículas U.T.M. 10x10 Km y en función de los resultados y la información recibida se eligieron determinadas zonas para realizar estaciones de escucha y espera. Determinamos durante el periodo de estudio la existencia de 25 grupos familiares. La densidad estimada en la provincia es de 2,10 – 3,28 lobos /100 km2. De los casos de mortalidad conocidos entre enero de 1999 y abril de 2002 (n=37), un elevado porcentaje se debió a atropellos (70,27%) principalmente en dos vías concretas y un 8,10% correspondió a envenenamientos. Actualmente la densidad del lobo en Ourense es superior a la obtenida en provincias limítrofes, pero amenazas de origen antrópico tanto directas (veneno, persecución ilegal...) como indirectas (incendios forestales, grandes infraestructuras viales, parques eólicos...) pueden estar condicionando la existencia de grupos familiares e incluso la presencia de la especie en determinadas zonas

Distribución y Aspectos Poblacionales del Lobo Ibérico (Canis lupus signatus) en las Provincias de Pontevedra y A Coruña (Galicia)/Distribution and Population Aspects of the Iberian Wolf (Canis lupus signatus) in the Provinces of Pontevedra and A Coruña (Galicia, Spain)

Wolf distribution range in Pontevedra and A Coruña provinces (north-west of the Iberian Peninsula) was determined by field surveys involving sampling routes to locate wolf signs and by questionnaires sent to agents of the Regional Government of Galicia’s Nature Conservation Service and to game societies in the study area. Results were recorded using 10x10 UTM squares. Wolf presence was detected in 67.05% of the squares in the study area, wolf distribution range in both provinces being estimated at approximately 9,600 km2 (6,400 km2 in A Coruña province and 3,200 km2 in Pontevedra province). Wolf distribution is continuous between both provinces, covering mainly the Dorsal Gallega mountain system and the west of A Coruña province. The latter is connected with the rest of the wolf distribution range in Galicia via the north of Pontevedra province. The entire study area was surveyed using 10x10 squares. The areas where most signs were recorded were selected for howling stations and observation points in order to locate packs (cubs and adults). We detected 29 packs (14 and 15 in A Coruña and Pontevedra provinces, respectively), with breeding being confirmed in 52% of them. Population size was estimated at 87-129 wolves in A Coruña province (1.36-2.02 wolves/100 Km2) and 95-140 wolves in Pontevedra province (2.97-4.38 wolves/100 km2). Areas with high wolf density (core populations) were chiefly along the Dorsal Gallega mountain system. Some packs were in highly humanized areas, which may explain why the main cause of the deaths recorded between January 2000 and October 2003 (n=29) was road collision (n=21)