Conserving butterflies in fragmented plantation forests: are edge and interior habitats equally important?

Edge effects are increasing in forest-dominated landscapes worldwide, due to increased fragmentation by other land uses. Understanding how species respond to edges is therefore critical to define adequate conservation measures. We compared the relative importance of interior and edge habitats for butterflies in a landscape composed of even-aged pine plantations interspersed with semi-natural habitats. Butterfly assemblages were surveyed simultaneously at the edge and the interior of 68 patches belonging to four main habitat types: herbaceous firebreaks, clearcuts and young pine stands, older pine stands, and deciduous woodlands. Butterfly species richness was higher at edges than in interior habitats, especially for pine stands. Assemblage composition differed significantly between edge and interior habitats, except for firebreaks. Of the 23 most abundant butterfly species, seven were significantly more abundant in one or all edge habitat types, five in interior habitats, and 11 species showed no edge-interior preference. Modelling the presence of individual species in edge habitats revealed the importance of habitat variables such as the abundance of nectar and host-plants, but also of the abundance of the same species in the adjacent interior habitat. Moreover, our results suggest that most species use several, different habitat types to find supplementary or complementary resources, including micro-climatic refuges to escape hot temperatures during summer. The use of adjacent edge and interior habitats by butterflies is probably a key process in such mosaic landscapes and underlines the importance of landscape heterogeneity for butterfly conservation.     

Density of deer in relation to the prevalence of Borrelia burgdorferi s.1. in Ixodes ricinus nymphs in Rambouillet forest, France

The Rambouillet Forest, a Lyme disease-endemic area near Paris, France, was surveyed from September 1994 to October 1995 to determine the risk periods and zones for humans. Firstly, during the period of Ixodes ricinus activity, abundance of nymphs is greater in spring than in autumn. Secondly, we observed significant variation in nymphal abundance between zones according to the density of cervids. The polymerase chain reaction (PCR) was used to detect DNA of Borrelia burgdorferi sensu lato in 461 unfed nymphs. DNA was detected in 38 nymphs (8.2%). By genospecific PCR based on the OspA gene, we detected the three pathogenic spirochetes with occurrences of 10.3, 31.1 and 58.6 for B. burgdorferi s.s., Borrelia garinii and Borrelia afzelii, respectively, indicating that B. afzelii is probably the main Borrelia species in the Rambouillet Forest. Finally, 11.5% of positive nymphs exhibited a double infection. Infection rates of I. ricinus nymphs by B. burgdorferi s.l. were not significantly different throughout the year for a given area, indicating that the risk periods of acquiring Lyme disease are mainly linked to nymph activity and correspond to spring and autumn. Likewise infection rates of nymphs were not significantly different between zones with a high density of deer (more than 100 animals per 100 ha) and zones with lower deer density (less than 20 animals per 100 ha). In addition to the role of deer as an amplifier of tick populations, these data indicate that zones with a high density of cervids should be considered as higher risk areas. © Rapid Science Ltd. 1998     

Importance of semi-natural habitats for the conservation of butterfly communities in landscapes dominated by pine plantations

While the area of plantation forests continues to increase worldwide, their contribution to the conservation of biodiversity is still controversial. There is a particular concern on the central role played by natural habitat remnants embedded within the plantation matrix in conserving species-rich insect communities. We surveyed butterflies in maritime pine plantation landscapes in south-western France in 83 plots belonging to seven habitat types (five successional stages of pine stands, native deciduous woodlands and herbaceous firebreaks). The effect of plot, habitat and landscape attributes on butterfly species richness, community composition and individual species were analysed with a General Linear Model (GLM), partial Canonical Correspondence Analysis (CCA) and the IndVal method. The most important factors determining butterfly diversity and community composition were the presence of semi-natural habitats (deciduous woodlands and firebreaks) at the landscape scale and the composition of understorey vegetation at the plot scale. Pure effects of plot variables explained the largest part of community variation (12.8%), but landscape factors explained an additional, independent part (6.7%). Firebreaks were characterized by a higher species richness and both firebreaks and deciduous woodlands harboured species not or rarely found in pine stands. Despite the forest-dominated landscape, typical forest butterflies were rare and mainly found in the deciduous woodlands. Threatened species, such as Coenonympha oedippus and Euphydryas aurinia, were found in pine stands and in firebreaks, but were more abundant in the latter. In the studied plantation forest, the conservation of butterflies depends mainly on the preservation of semi-natural habitats, an adequate understorey management and the maintenance of soil moisture levels.     

Variations in Ixodes ricinus Density and Borrelia Infections Associated with Cattle Introduced into a Woodland in The Netherlands

The effect of introduced large herbivores on the abundance of Ixodes ricinus ticks and their Borrelia infections was studied in a natural woodland in The Netherlands. Oak and pine plots, either ungrazed or grazed by cattle, were selected. Ticks were collected weekly by blanket dragging. Borrelia infections were determined by PCR and restriction fragment length polymorphism. Rodent densities were estimated using mark-release-recapture methods. On occasion, the cattle were inspected for tick infestations. Meteorological data were recorded for each habitat. Significantly more ticks were collected in the ungrazed woodland than in the grazed woodland. The ungrazed oak habitat had higher tick densities than the pine habitat, while in the grazed habitats, tick densities were similar. Borrelia infection rates ranged from zero in larvae to 26% in nymphs to 33% in adult ticks, and B. afzelii, B. burgdorferi sensu stricto, B. garinii, and B. valaisiana were the species involved. Coinfections were found in five ticks. There was no effect of the presence of cattle on Borrelia infections in the ticks. In the ungrazed area, Borrelia infections in nymphs were significantly higher in the oak habitat than in the pine habitat. More mice were captured in the ungrazed area, and these had a significantly higher tick burden than mice from the grazed area. Tick burden on cattle was low. The results suggest that grazing has a negative effect on small rodents as well as on ticks but not on Borrelia infections. Implications of these results for management of woodland reserves and risk of Lyme disease are discussed.     

Borrelia Burgdorferi Sensu Lato in Ixodes Ricinus Ticks and Rodents in a Recreational Park in South-Western Ireland

Ixodes ricinus ticks infected with Borrelia burgdorferi sensu lato were numerous on the edges of paths and roads in a recreational park in south-western Ireland. The abundance of ticks at different sites was related to the presence of deer, but a negative relationship was shown between tick abundance and tick infection rates. This is thought to be due to the deposition of large numbers of uninfected ticks by deer, which are apparently not good reservoir hosts of B. burgdorferi s.l. Blood meal analysis only detected deer DNA in uninfected nymphs. Reservoir competent rodents, Apodemus sylvaticus and Clethrionomys glareolus, were abundant at all sites and a high proportion of captured specimens were infested with larval ticks. However, very few rodents were infected with B. burgdorferi s.l. and none of the unfed infected nymphs analysed for the identity of their larval blood meal had fed on rodents. The spirochaetes detected in I. ricinus in the study area may be poorly adapted to rodents or are not transmitted readily because of the absence of nymphal infestation. The majority of spirochaetes in these ticks were apparently acquired from non-rodent hosts, such as birds.     

Distribution of an increasing roe deer population in a fragmented Mediterranean landscape

This paper describes roe deer Capreolus capreolus distribution in central Spain, where the species has spread from the mountains into peripheral agricultural areas In this region, it is more abundant in forest fragments near the mountains than in those further away, in pine and oak woodlands than in sclerophyllous forests, and in forests with open water than in those lacking this resource The paper also analyzes whether habitat quality and geographic location of forests with respect to roe deer source areas are the two basic causes of its distribution, as predicted by some models of the species distribution in fragmented landscapes The results corroborate this hypothesis revealing that roe deer abundance is linked negatively to sclerophyllous forest cover and distance from mountains We conclude that this type of farmland seems to be sub-optimal for roe deer in comparison with forested, moist mountains     

Habitat-related variation in infestation of lizards and rodents with Ixodes ticks in dense woodlands in Mendocino County, California

During the spring and early summer of 2002, we examined the relative importance of Borrelia-refractory lizards (Sceloporus occidentalis, Elgaria spp.) versus potential Borrelia burgdorferi sensu lato (s.l.)-reservoirs (rodents) as hosts for Ixodes pacificus immatures in 14 woodland areas (six oak, five mixed oak/Douglas fir, and three redwood/tanoak areas) distributed throughout Mendocino County, California. Lizards were estimated to serve as hosts for 93-98% of all larvae and > or =99.6% of all nymphs infesting lizards or rodents in oak woodlands and oak/Douglas fir sites in the southern part of the county. In redwood/tanoak woodlands and oak/Douglas fir sites in northern Mendocino County, the contribution of rodents to larval feedings reached 36-69% but lizards still accounted for 94-100% of nymphal bloodmeals. From late April to mid-June, I. pacificus larvae were recovered from 95 to 96% of lizards and dusky-footed woodrats (Neotoma fuscipes) and from 59% of Peromyscus spp. mice. In contrast, 99% of lizards but few woodrats (15%) and none of the mice were infested by nymphs. Comparisons of tick loads for 19 lizard-Peromyscus spp. mouse pairings, where the lizard and mouse were captured within 10m of each other, revealed that the lizards harbored 36 times more larvae and >190 times more nymphs than the mice. In oak woodlands, loads of I. pacificus larvae decreased from late April/early May to late June for S. occidentalis lizards but increased for Peromyscus spp. mice. We conclude that the relative utilization of Borrelia-refractory lizards, as compared to rodents, by I. pacificus larvae was far higher in dry oak woodlands than in moister habitats such as redwood/tanoak and oak/Douglas fir woodlands in northern Mendocino County. Non-lizard-infesting potential enzootic vectors of B. burgdorferi s.l. (I. angustus and I. spinipalpis) were recorded from rodents in three of six oak woodland areas, two of five oak/Douglas fir woodland areas, and two of three redwood/tanoak woodland areas.     

Ticks in the ecotone: the impact of agri-environment field margins on the presence and intensity of Ixodes ricinus ticks (Acari: Ixodidae) in farmland in southern England

The present study aimed to assess whether agri-environment field margins provide a habitat for the sheep/deer tick Ixodes ricinus. Field studies were conducted in arable farmland in southern England in both extant and newly constructed field margins. The presence and intensity (i.e. the mean number of nymphs per transect, excluding zeros) of questing nymphs and adult I. ricinus were compared between field margins with three adjacent habitats: woodland, hedgerow and arable land. The presence and intensity of ticks within a field margin was also compared between three ecozones: the ecotone, the margin and the crop. It was found that field margins do support I. ricinus, although the intensity of ticks was associated with field margins with adjacent woodland, with a higher tick intensity along the ecotonal ecozone, compared with the rest of the margin or the crop edge. The presence of a hedge also increased the likelihood of finding questing nymphs in a field margin compared with a margin adjacent to arable land. This effect, however, was less pronounced than in field margins with adjacent woodland. The provision of footpaths within the margin (at least 1–2 m from the ecotone), or on the edge of the crop where paths run next to woodland known to be an important tick habitat, could be promoted to minimize tick exposure. In addition, based on the results of the present study, raising awareness that walking alongside woodlands also constitutes a tick risk could be promoted.     

Structure and utilisation of the early oakwoods

Summary

The paper explores whether any of the familar range of current oakwood structures in the west of Scotland can be used as realistic analogues for the prehistoric oakwoods. Even for the early historic oak woodlands we have no detailed knowledge of previous structures and composition.

The structure of today's oak woodlands, and to some extent even the legacy of species within that habitat, are a type of biocultural heritage. The oak woodlands that we see today are the product of a long interaction: between man's use of the woodlands and the ongoing natural processes within the oakwood ecosystem.

Grazing animals, especially domestic cattle and red deer, have played a key part in determining oak woodland structure in historic times, and perhaps have a future role too. Are there lessons to be drawn from knowledge of past management and regeneration of oak which are relevant to the present day, when most managers are finding it difficult to regenerate oak woodlands on any scale?

Understanding past utilisation and structure of oak woodlands is valuable mainly as a guide to future management. Indeed one might ask which models and structures are relevant for managing an oak woodland resource now regarded mainly as a wildlife habitat?     

Lichens — the biodiversity value of western woodlands

Summary

The Atlantic broad-leaved woodlands of Britain are of international renown for their lichen floras. They are inhabited by 517 lichens, representing 28.3% of the total lichen flora and 73.2% of all British woodland lichens, and they are the main habitat for 165 species. Of these, 31 have a marked southern distribution and do not reach Scotland, whereas 26 species are found in Scotland, but not England or Wales. Their British Red-listed species are outnumbered by the 86 species for which Britain has International Responsibility.

Within the Atlantic broad-leaved woodlands, only 30 lichens show a preponderance for oak. With the exception of some ancient oakwoods in southern England, a high lichen biodiversity is rarely dependent on a dominance of oak in the woodland canopy, more usually it is the result of a long ecological continuity, often a varied tree and shrub composition, a varied canopy density, and good air quality. Consequently, the oak stands within former ‘industrial’ woodlands have a much lower lichen biodiversity compared with woodlands that have a history as ‘pasture woodland’ or, as with some ravine woodlands, have otherwise escaped intensive management.

The life-history of an oak tree is considered in relation to the niches it provides for lichen colonisation with time. Some management scenarios are provided with the enhancement of the lichen interest of former ‘industrial’ oakwoods as an objective.     

Tick burden on European roe deer (<Emphasis Type="Italic">Capreolus capreolus</Emphasis>)

In our study we assessed the tick burden on roe deer (Capreolus capreolus L.) in relation to age, physical condition, sex, deer density and season. The main objective was to find predictive parameters for tick burden. In September 2007, May, July, and September 2008, and in May and July 2009 we collected ticks on 142 culled roe deer from nine forest departments in Southern Hesse, Germany. To correlate tick burden and deer density we estimated deer density using line transect sampling that accounts for different detectability in March 2008 and 2009, respectively. We collected more than 8,600 ticks from roe deer heads and necks, 92.6% of which were Ixodes spp., 7.4% Dermacentor spp. Among Ixodes, 3.3% were larvae, 50.5% nymphs, 34.8% females and 11.4% males, with significant seasonal deviation. Total tick infestation was high, with considerable individual variation (from 0 to 270 ticks/deer). Adult tick burden was positively correlated with roe deer body indices (body mass, age, hind foot length). Significantly more nymphs were found on deer from forest departments with high roe deer density indices, indicating a positive correlation with deer abundance. Overall, tick burden was highly variable. Seasonality and large scale spatial characteristics appeared to be the most important factors affecting tick burden on roe deer.     

Attachment site selection of ticks on roe deer, <Emphasis Type="Italic">Capreolus capreolus</Emphasis>

The spatio-temporal attachment site patterns of ticks feeding on their hosts can be of significance if co-feeding transmission (i.e. from tick to tick without a systemic infection of the host) of pathogens affects the persistence of a given disease. Using tick infestation data on roe deer, we analysed preferred attachment sites and niche width of Ixodes ticks (larvae, nymphs, males, females) and investigated the degree of inter- and intrastadial aggregation. The different development stages showed rather consistent attachment site patterns and relative narrow feeding site niches. Larvae were mostly found on the head and on the front legs of roe deer, nymphs reached highest densities on the head and highest adult densities were found on the neck of roe deer. The tick stages feeding (larvae, nymphs, females) on roe deer showed high degrees of intrastadial spatial aggregation, whereas males did not. Male ticks showed large feeding site overlap with female ticks. Feeding site overlap between larval-female and larval-nymphal ticks did occur especially during the months May–August on the head and front legs of roe deer and might allow pathogen transmission via co-feeding. Tick density, niche width and niche overlap on roe deer are mainly affected by seasonality, reflecting seasonal activity and abundance patterns of ticks. Since different tick development stages occur spatially and temporally clustered on roe deer, transmission experiments of tick-borne pathogens are urgently needed.     

Risk factors in habitats of the tick Ixodes ricinus influencing human exposure to Ehrlichia phagocytophila bacteria

Ixodes ricinus L. (Acari: Ixodida) were sampled during 1996-99 in southern Scotland, on vegetation using cloth drags, on humans by removal from clothing and on roe deer (Capreolus capreolus L.) by searching legs of culled deer. Developmental microclimate was recorded by automatic recorders and questing microclimate by portable instruments during tick collections. Ticks and deer were examined for infection with Ehrlichia phagocytophila bacteria (Rickettsiales) using microscopy and polymerase chain reaction. This pathogen causes tick-borne fever of sheep in Europe and human granulocytic ehrlichiosis in North America, but in Europe human clinical ehrlichiosis due to E. phagocytophila has not been recorded despite serological evidence of exposure. Among three types of habitat, coniferous woodland was most infested with questing ticks (560 ticks/km of drag; mean numbers collected on long trousers: 24.3 larvae, 13.5 nymphs and 0.8 adult ticks/km walked), deciduous woodland had slightly lower infestation (426 ticks/km drag) and upland sheep pasture had much lower infestation (220 ticks/km drag). Of the three main vegetation types, bracken was least infested (360 ticks/km drag), ericas most (430 ticks/km drag) and grassland had intermediate infestation density (413 ticks/km drag). Questing and developmental microclimates were poor predictors of exposure within these habitats, except lower infestation of pastures was attributed to greater illumination there. Collectors who walked a total of 300 km through all habitats (taking 360 h in all seasons), wearing cotton trousers hanging outside rubber boots, were bitten by only four nymphs and 11 larvae of I. ricinus (but no adult ticks). There was a negative correlation between densities of deer and ticks collected, although presence of deer remains a major indicator of exposure. The proportion of infected ticks was fairly uniform at four sites studied. Overall prevalence of E. phagocytophila in I. ricinus was 3.3% in nymphs (40/1203) but only approximately 1.5% in adults of both sexes (although males do not bite). It was estimated that nymphs of I. ricinus gave 4.4% probability of one infected bite/person/year (for occupational exposure during this research) due to presence in all seasons and habitats, their human biting rate of 0.011 nymphs/h or 0.013 nymphs/km and widespread infection with E. phagocytophila. The frequency distribution of intensity of infection in ticks was approximately normal (mean 98 morulae/nymph infected), thus there is a high risk of receiving a high dose from any one infected tick bite.     

Phylogeography of the white-breasted nuthatch (Sitta carolinensis): diversification in North American pine and oak woodlands

Pine and oak woodlands are common North American floral communities with distinct regional species composition. The white-breasted nuthatch (Aves: Sitta carolinensis) is a common resident bird of North American pine and oak woodlands, and is distributed continentally across the highly disjunct distribution of these woodlands. We propose three historical hypotheses to explain the evolution of the white-breasted nuthatch in its principal habitat. (i) The species evolved in situ in the regional pine-oak communities and the isolation of populations in these regions is captured in cryptic genetic variation. (ii) Migration of individuals between regions is frequent enough to maintain the widespread distributions and prevent regional divergence. (iii) The species have recently expanded to occupy their current distributions and an insufficient amount of time has passed for divergence to occur. Phylogenetic analysis of mitochondrial DNA (ND2 gene) variation (N = 216) in the white-breasted nuthatch reveals four reciprocally monophyletic clades concordant with the distribution of the regional North American pine and oak woodlands, and supports hypothesis 1 of in situ evolution of populations in the regional pine and oak communities. Within-clade population structure and demographic history are also discussed.     

Characteristics of woods used recently and historically by Lesser Spotted Woodpeckers Dendrocopos minor in England

Lesser Spotted Woodpecker Dendrocopos minor numbers have declined greatly in England since the early 1980s for reasons that are not yet fully understood. It has been suggested that the species’ decline may be linked to the increase in Great Spotted Woodpeckers Dendrocopos major, changes in woodland habitat quality (such as deadwood abundance) and landscape‐scale changes in tree abundance. We tested some of these hypotheses by comparing the characteristics of woods in southern England where the species is still relatively numerous with those of woods used in the 1980s before the major decline. In each time period, habitat, predator and landscape information from woods known to be occupied by Lesser Spotted Woodpeckers was compared with those found to be unoccupied during surveys. Before the main period of decline, Lesser Spotted Woodpeckers used oak‐dominated, mature, open woods with a large amount of standing deadwood. Habitat use assessed from recent data was very similar, the species being present in mature, open, oak‐dominated woodlands. There was a strong relationship between wood use probability and the extent of woodland within a 3‐km radius, suggesting selection for more heavily wooded landscapes. In recent surveys, there was no difference in deadwood abundance or potential predator densities between occupied and unoccupied woods. Habitat management should focus on creating and maintaining networks of connected woodlands in areas of mature, open woods. Finer‐scale habitat selection by Lesser Spotted Woodpecker within woodlands should be assessed to aid development of beneficial management actions.     

Deciduous woodland conservation under heavy deer browsing on Devils Tower National Monument, USA

Native deciduous woodlands comprise <5% of the vegetation in the Black Hills and northern plains of the USA and appear to be in decline. Because deciduous woodlands comprise 18% of the land cover on Devils Tower National Monument (DTNM), this natural area is potentially important for the conservation of these plant communities. Lack of tree regeneration and accumulation of dead wood suggest that the native deciduous woodlands on DTNM may die out under persistent, heavy deer (Odocoileus virginianus, O. hemionus) browsing. We monitored vegetation changes for seven years (1989–1996) inside and outside 6 deer exclosures on DTNM to determine the resilience of native woodland communities when protected from browsing, and to parameterize models that evaluate specific fencing scenarios for managing woodland communities. The herbaceous woodland understory was not directly, but indirectly affected by deer browsing because graminoid biomass declined as tall shrubs recovered. Tall shrubs, dominated by Prunus spp. showed the most rapid and consistent recovery across sites. Models of shrub growth indicated that rotational fencing for short durations (10 years) produced the highest long-term increase in tall-shrub densities and the greatest evenness among size classes. Because deciduous woodlands currently are resilient and occur in small patches, fencing may provide a practical management alternative to deer culling programs.     

Ixodes ricinus, transmitted diseases and reservoirs

The tick Ixodes ricinus has been recorded in most Italian regions especially in thermo-mesophilous woods and shrubby habitats where the relative humidity allow the tick to complete its 3 year developmental cycle, as predicted for the European climatic ranges. This tick acts both as vector and reservoir for a series of wildlife zoonotic pathogens, especially the agents of Lyme diseases, Tick borne encephalitis and Human Granulocytic Ehrlichiosis, which are emerging in most of Europe. To assess the spatial distribution of these pathogens and the infection risk for humans and animals within the territory of the Province of Trento, we carried out a long term study using a combination of eco-epidemiological surveys and mathematical modelling. An extensive tick collection with a GIS based habitat suitability analysis allowed us to identify the areas where tick occurs at various density. To identify the areas with higher infection risk, we estimated the values of R0 for Borrelia burgdorferi s.l., TBE virus and Anaplasma phagocytophila under different ecological conditions. We assessed the infection prevalence in the vector and in the wildlife reservoir species that play a central role in the persistence of these infections, ie the small mammals A. flavicollis and C. glareolus. We also considered the double effect of roe deer (Capreolus capreolus) which act as reservoir for A. phagocytophila but is an incompetent host for B. burgdorferi and TBE virus, thus reducing the infection prevalence in ticks of these last two pathogens. Infection prevalence with B. burgdorferi and A. phagocytophila in the vector was assessed by PCR screening 1212 I. ricinus nymphs collected by dragging in six main study areas during 2002. The mean infection prevalence recorded was 1.32% for B. burgdorferi s.l. and 9.84% for A. phagocytophila. Infection prevalence in nymphs with TBE virus, as assessed in a previous study was 0.03%. Infection prevalence in rodents was assessed by screening (with ELISA and PCR) tissues and blood samples collected from 367 rodent individuals trapped extensively during 2002 within 6 main study areas. A. flavicollis (N=238) was found to be infected with all three pathogens investigated, with infection prevalence ranging from 3.3% for TBE virus to 11.7% for A. phagocytophila, and 16.6% with B. burgdorferi s.l. C. glareolus (N=108) showed an infection prevalence of 6.5% with A. phagocytophila and 12.7% with B. burgdorferi s.l., while no individuals were infected with TBE virus. We also screened 98 spleen samples collected from roe deer with PCR, resulting in a mean prevalence of infection with A. phagocytophila of 19.8%. Using a deterministic model we explored the condition for diseases persistence under different rodent and roe deer densities. R0 values resulted largely above 1 for B. burgdorferi s.l. in the vast majority of the areas classified as suitable for I. ricinus occurrence in Trentino, while the condition for TBE persistence appeared to be more restricted by a combination of climatic condition and host densities.     

Evaluating the benefits of CAP reforms: Can afforestations restore bird diversity in Mediterranean Spain?

Current Common Agricultural Policy (CAP) subsidies in the Mediterranean region tend to prioritize afforestation on former arable land with oaks rather than pines because pine plantations would maintain lower biological diversities than native forests. Nevertheless, no thorough evaluations of the conservation values of pine plantations as compared to oak remnants have been carried out to date. We analyze the diversity and conservation value of bird assemblages breeding in 200 remnants of Holm oak Quercus ilex woodlands and 82 mature (>50-year-old) pine plantations in central Spain, a Mediterranean region mostly devoted to arable farming. Species–area relationships were compared between forest types. The conservation value of bird assemblages was assessed using the “Species of European Conservation Concern” (SPEC) classification of Burfield and van Bommel [(2004). Birds in Europe: Populations estimates, trends and conservation status. Cambridge: BirdLife International]. Overall numbers of bird species maintained by oak and pine archipelagoes were rather similar, but species–area relationships differed between forest types. Intercepts were higher in oak fragments, whereas slopes were steeper in pine plantations. Small oak fragments held more species (mainly Mediterranean Sylvia warblers) than plantations, whereas large plantations held more species than large oak remnants. Differences in species–area relationships seemed to be due to differences in vegetation structure, especially understorey shrub cover and tree height and cover. We recorded nine SPECs, all exclusive (6) or near-exclusive (3) to oak woodlands, although such woodlands do not appear to be critical for their conservation. Hence, we conclude that pine afforestations have played a role for maintaining and restoring forest bird communities in the farming landscapes of central Spain. Promoting large and shrubby plantations would enhance their conservation value for breeding birds, together with promoting growth, regeneration and expansion of Holm oak remnants by means of set-aside measures previous or alternative to oak reafforestation. The increasing importance of non-commercial as compared to commercial values of Mediterranean forests would justify subsidizing the proposed policy.     

Integrated Assessment of Behavioral and Environmental Risk Factors for Lyme Disease Infection on Block Island,Rhode Island

Peridomestic exposure to Borrelia burgdorferi-infected Ixodes scapularis nymphs is considered the dominant means of infection with black-legged tick-borne pathogens in the eastern United States. Population level studies have detected a positive association between the density of infected nymphs and Lyme disease incidence. At a finer spatial scale within endemic communities, studies have focused on individual level risk behaviors, without accounting for differences in peridomestic nymphal density. This study simultaneously assessed the influence of peridomestic tick exposure risk and human behavior risk factors for Lyme disease infection on Block Island, Rhode Island. Tick exposure risk on Block Island properties was estimated using remotely sensed landscape metrics that strongly correlated with tick density at the individual property level. Behavioral risk factors and Lyme disease serology were assessed using a longitudinal serosurvey study. Significant factors associated with Lyme disease positive serology included one or more self-reported previous Lyme disease episodes, wearing protective clothing during outdoor activities, the average number of hours spent daily in tick habitat, the subject’s age and the density of shrub edges on the subject’s property. The best fit multivariate model included previous Lyme diagnoses and age. The strength of this association with previous Lyme disease suggests that the same sector of the population tends to be repeatedly infected. The second best multivariate model included a combination of environmental and behavioral factors, namely hours spent in vegetation, subject’s age, shrub edge density (increase risk) and wearing protective clothing (decrease risk). Our findings highlight the importance of concurrent evaluation of both environmental and behavioral factors to design interventions to reduce the risk of tick-borne infections.