Blood parasites may act as modulators of their hosts' ecology, life histories and fitness. We studied the prevalence of Plasmodium sp., Haemoproteus sp. and Leucocytozoon sp. and their effects on morphological, biochemical and haematological variables and on breeding effort of Great Tits Parus major. Total prevalence (percentage of individuals infected by any parasite) ranged from 7.7% to 61.1%. There was an overall positive association in prevalence between the three haematozoan parasites. No effect of sex or age on infection status was observed. Negative impacts of infection on physiological condition depended largely on year and ⁄ or season and included effects on body condition index, plasma protein and haemoglobin index. There were also indications that parasite infection increased immune response and stress levels and activated antioxidant defence mechanisms. Males with higher fledging success had a higher probability of Haemoproteus infection, and females laying heavier eggs had a higher probability of Plasmodium infection. However, clutch size was negatively associated with the probability of infection by Leucocytozoon and Haemoproteus. Surprisingly, males raising second broods had a lower prevalence of both Haemoproteus and Leucocytozoon. Only 5.7% of first-brood nestlings were infected, but those in infected nestboxes had a lower heterophil ⁄ lymphocyte ratio. This study confirms the pathogenicity of blood parasites to the host by demonstrating negative effects of infection on both physiology and breeding performance.

BackgroundFew studies have assessed the effectiveness of the Protected Area networks on the conservation status of target species. Here, we assess the effectiveness of the Portuguese Natura 2000 (the European Union network of protected areas) in maintaining a species included in the Annex I of the Bird Directive, namely the population of a priority farmland bird, the little bustard Tetrax tetrax.MethodsWe measured the effectiveness of the Natura 2000 by comparing population trends across time (2003–2006 and 2016) in 51 areas, 21 of which within 12 Special Protection Areas (SPA) that were mostly designated for farmland bird conservation and another 30 areas without EU protection.ResultsOverall, the national population is estimated to have declined 49% over the last 10–14 years. This loss was found to be proportionally larger outside SPA (64% decline) compared to losses within SPA (25% decline). However, the absolute male density decline was significantly larger within SPA .DiscussionIn spite of holding higher population densities and having prevented habitat loss, we conclude that Natura 2000 was not effective in buffering against the overall bustard population decline. Results show that the mere designation of SPA in farmland is not enough to secure species populations and has to be combined with agricultural policies and investment to maintain not only habitat availability but also habitat quality.

Habitat loss and non-native species are two key drivers of biodiversity decline. The importance of their interactions is widely recognized, but remains poorly understood. We used the endemic-rich bird assemblage of São Tom e Island to study this type of interactions. We built species-specific binomial generalized linear models for 33 terrestrial bird species, based on presence-absence data from 2398 sampling points. Meta-analysis techniques revealed that land use was more important in explaining distribution than topographic variables, rainfall, or distance to coast for the studied bird species. Native species were more likely to occur in remote rainy forests at higher altitudes, whereas non-native species were more likely to occur in non-forested ecosystems, being associated with humanized lowland areas in the drier flat regions of São Tom e. The susceptibility of anthropogenic ecosystems to the establishment of non-native birds suggests that disturbance favours these species. An analysis of species feeding guilds further suggests that these habitat associations might be linked to resource availability, as a large proportion of non-native species rely on seeds, which are clearly more available outside the best-preserved forests. Contrarily, very few native birds seem to be using this resource, and instead rely on more complex ecological interaction, such as carnivory and frugivory. This difference may reduce the chance of negative interactions between native and non-native species (e.g. competition), but this should not be misunderstood for a lack of negative effects of the latter. Our results indicate that land-use intensification is the key driver of biodiversity changes on São Tom e, potentially facilitating the expansion of non-native species and demoting ecological complexity. Therefore, protecting the best-preserved forests is the single most important measure to ensure the conservation of native species. Animal Conservation.

SummarySão Tomé holds 20 endemic bird species, including the little known and ‘Critically Endangered’ Dwarf Olive Ibis Bostrychia bocagei, São Tomé Fiscal Lanius newtoni and São Tomé Grosbeak Neospiza concolor. We conducted a systematic survey of the core forest area, performing 1,680 point counts and compiling occasional observations, which enabled the identification of new areas of occurrence for the target species. MaxEnt distribution modelling suggested that the ibis and fiscal have roughly half of the potential area of occurrence that had been assumed (127 and 117 km2, respectively), while it more than doubled that of the grosbeak (187 km2). The south-west central region of the island, most of which is included in the São Tomé Obô Natural Park, has the highest potential for the Critically Endangered birds. We confirmed the association of all target species with native forest. The ibis preferred high tree density, while the fiscal selected low tree density and intermediate altitudes. Despite very restricted ranges, population sizes seem to be larger than previously assumed. These results suggest that the fiscal and grosbeak might be better classified as ‘Endangered’, while the ibis should maintain its status under different criteria, due to a very restricted range during the breeding season. This work provides vital ecological knowledge to support conservation action focusing on these species and their habitats, highlighting the need to improve the effectiveness of the São Tomé Obô Natural Park in protecting its unique biodiversity.