bluuebunny/crossref_metadata_2025_split huggingface dataset:
Incidence of serum antibody titers against varicella zoster virus in Japanese patients with herpes zoster
Authors: Miyachi Motoko , Ihara Honoka , Imafuku Shinichi 
Published: December 2016

AbstractHerpes zoster is an internal reactivation of varicella zoster virus following establishment of latent infection in the dorsal root ganglia during primary infection, which presents as chickenpox. Therefore, serologically, herpes zoster patients already have anti‐varicella zoster virus immunoglobulin G at the onset of disease. Hence, positive serum antibody does not confirm the diagnosis of herpes zoster. We retrospectively investigated the incidence of varicella zoster virus‐specific complement fixation in 865 zoster patients at initial presentation to a dermatology clinic. As a result, 66% of patients showed negative complement fixation, with patient numbers decreasing as titer increased. Paired complement fixation tests conducted within a short period showed a marked elevation in titer, and complement fixation titer gradually decreased after a year. Furthermore, incidence showed no correlation with patient age. These observations indicate that the complement fixation titer at first visit is mainly influenced by the duration from onset to presentation at clinic. Our findings indicate that a positive complement fixation result by single‐point testing confirms at least recent onset of herpes zoster, while paired tests can confirm disease when primary tests are negative.
Tree species functional group is a more important driver of soil properties than tree species diversity across major European forest types
Authors: Dawud Seid Muhie , Raulund‐Rasmussen Karsten , Ratcliffe Sophia , Domisch Timo , Finér Leena , Joly François‐Xavier , Hättenschwiler Stephan , Vesterdal Lars 
Published: December 2016

Summary

The influence of tree species diversity and functional group on soil properties (carbon stock, pH and C/N ratio) has not been explored across major European forest types.

We evaluated the relative importance of tree species diversity and functional group for soil carbon (C) stocks, C/N ratio and pH in major European forest types in the six regions Finland, Poland, Germany, Romania, Italy and Spain. We sampled soils in 209 permanent plots along a species diversity gradient from monocultures to five‐species mixtures.

Carbon stocks in the topsoil (forest floor (FF), 0–10 cm and FF + 0–10 cm) were positively, but weakly, related to diversity across the regions. While the C/N ratio in the FF + 0–10 cm layer decreased significantly with increasing diversity in the Spanish region, pH was unrelated to species diversity across the regions. Tree species functional group (in terms of conifer proportion, CP) explained a larger proportion of the variability in soil properties than diversity. Conifer admixture increased C stock and C/N ratio, and decreased pH, but the impacts differed between the regions in some layers. Differences in mean annual temperature, actual evapotranspiration and soil texture between the regions were possible driving factors behind the different CP effects in Finland, Spain and Germany.

The results imply that targeted selection of tree species with desired characteristics, e.g. complementary traits for resource use, is a preferred management approach for influencing soil C stock, C/N ratio and pH in mixed forests rather than increasing tree species diversity per se.

A lay summary is available for this article.
Does water shortage generate water stress? An ecohydrological approach across Mediterranean plant communities
Authors: Barkaoui Karim , Navas Marie‐Laure , Roumet Catherine , Cruz Pablo , Volaire Florence 
Published: December 2016

Summary

The interactions between hydrological and ecological processes are key issues to improve our predictions of ecosystem responses to increasing droughts. However, predicting the dynamics and the impacts of vegetation water stress remains challenging because of complex ecohydrological feedbacks. The ecohydrological optimality approach proposes that functional adjustments within plant communities may buffer the increase in vegetation water stress despite local water shortage.

This study aimed to test whether vegetation water stress may be invariant across contrasting plant communities, reflecting possible optimality processes. We addressed the following question: does a lower soil water storage capacity under the same climate generate greater vegetation water stress over time? We hypothesized that vegetation water stress would be buffered around a low and constant level through the adjustment of vegetation biomass productivity net primary productivity (NPP), evapotranspiration (ET) and/or water‐use efficiency (WUE) in relation with local soil water storage capacity.

We monitored 12 native plant communities distributed along a gradient of soil water storage capacity (ranging from 20 mm to 120 mm) during five successive years. Net primary productivity, ET, WUE as well as soil water dynamics were assessed and modelled for each plant community throughout the 5 years of study. Vegetation water stress was determined for each plant community as the deviation of between actual ET and their maximum ETm rate achieved under non‐limiting conditions.

We found that NPP and ET were together proportionally related to local soil water storage capacity across the 5 years of study while WUE did not differ between plant communities. Vegetation water stress was found quite similar for all plant communities whatever the soil water storage capacity. These results suggested that vegetation water stress was strongly buffered by the community‐level plant growth rates and total water use along the soil gradient, but not by WUE.

Our results suggest that stressful environments rarely exist for plant communities. A dynamic scaling relationship between NPP and ET may underpin the control of vegetation water stress over seasonal and pluriannual time‐scales. Such results could contribute to better understanding processes associated with ecohydrological optimality and improve the predictions of vegetation dynamics under increasing droughts.

A lay summary is available for this article.
Resource selection and landscape change reveal mechanisms suppressing population recovery for the world's most endangered antelope
Authors: Ali Abdullahi H. , Ford Adam T. , Evans Jeffrey S. , Mallon David P. , Hayes Matthew M. , King Juliet , Amin Rajan , Goheen Jacob R. 
Published: December 2016

Summary

Understanding how bottom‐up and top‐down forces affect resource selection can inform restoration efforts. With a global population size of <500 individuals, the hirola Beatragus hunteri is the world's most endangered antelope, with a declining population since the 1970s. While the underlying mechanisms are unclear, some combination of habitat loss and predation are thought to be responsible for low abundances of contemporary populations.

Efforts to conserve hirola are hindered by a lack of understanding as to why population density remains low, despite eradication of the viral disease, rinderpest. To elucidate factors underlying chronically low numbers, we examined resource selection and landscape change within the hirola's native range. Because hirola are grazers, we hypothesized that the availability of open areas would be linked both to forage and safety from predators. We quantified: (i) changes in tree cover across the hirola's historical range in eastern Kenya over the past 27 years; (ii) how tree cover has influenced resource selection by hirola; and (iii) interactions between tree cover and predation.

Between 1985 and 2012, tree cover increased by 251% across the historical range of hirola. Tree encroachment was associated with a 98% decline of hirola and elephant Loxodonta africana populations, a 74% decline in cattle Bos indicus, an increase in browsing livestock by 327%, and a reduction in rainfall.

Although hirola avoided tree cover, we found no evidence that predation on hirola increased with increasing tree cover.

Synthesis and applications. Hirola may qualify as a refugee species, in which contemporary populations are restricted to suboptimal habitat and exhibit low survival, reproduction or both. The extinction of hirola would be the first of a mammalian genus on the African continent in modern history. We conclude that contemporary low numbers of hirola are due at least partly to habitat loss via tree encroachment, triggered by some combination of elephant extirpation, overgrazing, drought and perhaps fire suppression. We recommend a combination of rangeland restoration efforts (including conservation of elephants, manual clearing of trees, and grass seeding), increased enforcement of an existing protected area (Arawale National Reserve), and reintroductions to enhance recovery for this endangered species. These efforts will rely on enhanced support from the international conservation community and the cooperation of pastoralist communities with which the hirola coexist.
Prioritizing landscapes for restoration based on spatial patterns of ecosystem controls and plant–plant interactions
Authors: Barbosa Jomar M. , Asner Gregory P. 
Published: December 2016

Summary

The widespread degradation of natural ecosystems requires cost‐efficient restoration techniques that minimize risk and consider context‐specific restoration conditions. However, meeting these demands can be difficult because information on ecosystem‐level factors controlling vegetation and continuous spatial data on species interactions are often lacking.

Using airborne light detection and ranging (LiDAR) data from a Hawaiian dry forest, we delineated crowns and assessed the 3D structure of more than 700 000 shrubs and trees. We used Random Forest machine learning to assess the relative importance of resource availability, environmental conditions, and disturbance regimes on canopy density. We then modelled and scaled up plant–plant interactions (i.e. potential nursery effects) to landscape units using a LiDAR‐derived Canopy Coalescence (CC) index. We used the relative importance of ecosystem factors, canopy cover, and CC index to prioritize landscapes for restoration.

Here, we demonstrate a methodological framework that prioritizes landscapes in need of restoration (i.e. planting woody species) using two ecological perspectives: (i) ecosystem‐level controls on remnant woody vegetation, and (ii) potential interactions between established canopies and seedlings (e.g. nursery effect, competition).

Our results highlight the heterogeneous nature of ecosystem‐level drivers affecting forest structure along elevation gradients. Consequently, the degree of potential nursery interactions between established canopies and seedlings at the landscape‐scale was context‐specific.

Synthesis and applications. Our study provides a methodological approach that prioritizes landscapes for restoration by identifying the main controls on tree spatial distribution and by inferring the favourable conditions for seedlings. This approach can guide land managers to define cost‐efficient restoration strategies for large ecological areas.
Sweat bees on hot chillies: provision of pollination services by native bees in traditional slash‐and‐burn agriculture in the Yucatán Peninsula of tropical Mexico
Authors: Landaverde‐González Patricia , Quezada‐Euán José Javier G. , Theodorou Panagiotis , Murray Tomás E. , Husemann Martin , Ayala Ricardo , Moo‐Valle Humberto , Vandame Rémy , Paxton Robert J. 
Published: December 2016

Summary

Traditional tropical agriculture often entails a form of slash‐and‐burn land management that may adversely affect ecosystem services such as pollination, which are required for successful crop yields. The Yucatán Peninsula of Mexico has a >4000 year history of traditional slash‐and‐burn agriculture, termed ‘milpa’. Hot ‘Habanero’ chilli is a major pollinator‐dependent crop that nowadays is often grown in monoculture within the milpa system.

We studied 37 local farmers’ chilli fields (sites) to evaluate the effects of landscape composition on bee communities. At 11 of these sites, we undertook experimental pollination treatments to quantify the pollination of chilli. We further explored the relationships between landscape composition, bee communities and pollination service provision to chilli.

Bee species richness, particularly species of the family Apidae, was positively related to the amount of forest cover. Species diversity decreased with increasing proportion of crop land surrounding each sampling site. Sweat bees of the genus Lasioglossum were the most abundant bee taxon in chilli fields and, in contrast to other bee species, increased in abundance with the proportion of fallow land, gardens and pastures which are an integral part of the milpa system.

There was an average pollination shortfall of 21% for chilli across all sites; yet the shortfall was unrelated to the proportion of land covered by crops. Rather, chilli pollination was positively related to the abundance of Lasioglossum bees, probably an important pollinator of chilli, as well indirectly to the proportion of fallow land, gardens and pastures that promote Lasioglossum abundance.

Synthesis and applications. Current, low‐intensity traditional slash‐and‐burn (milpa) agriculture provides Lasioglossum spp. pollinators for successful chilli production; fallow land, gardens and pasture therefore need to be valued as important habitats for these and related ground‐nesting bee species. However, the negative impact of agriculture on total bee species diversity highlights how agricultural intensification is likely to reduce pollination services to crops, including chilli. Indeed, natural forest cover is vital in tropical Yucatán to maintain a rich assemblage of bee species and the provision of pollination services for diverse crops and wild flowers.
Ecological and evolutionary effects of selective harvest of non‐lactating female ungulates
Authors: Rughetti Marco , Festa‐Bianchet Marco , Côté Steeve D. , Hamel Sandra 
Published: December 2016

Summary

Female ungulates are often selectively harvested according to their reproductive status. Because ungulate population growth depends heavily on adult female survival, it is crucial to understand the effects of this selective harvest. Recent studies revealed persistent individual differences in female reproductive potential, with a positive correlation of reproductive success over consecutive years. If current reproduction is correlated with lifetime reproductive success, then selective harvest of non‐lactating females should remove individuals of low reproductive potential, with lower impact on population growth than random harvest. If lifetime reproductive success has a genetic basis, selective harvest may also increase the proportion of successful females.

We used an individual‐based model to understand the short‐term effects of harvest intensity and hunter selectivity on population dynamics, accounting for both heterogeneity in reproductive potential and orphan survival. We also explored the long‐term effect of harvest as a selective pressure on female heterogeneity.

Selective harvest of non‐lactating females reduced survival to primiparity compared to random harvest, because of high harvest rates of pre‐reproductive females. After primiparity, however, females of higher reproductive potential had higher survival under selective than random harvest. Therefore, the overall effect on population dynamics depends on a trade‐off between a high harvest of pre‐reproductive females and a reduced harvest of reproductive females with high reproductive potential.

Female heterogeneity and the length of the pre‐reproductive period affected this trade‐off. Over the short term, high heterogeneity in reproductive potential of pre‐reproductive females made selective harvest the most effective strategy to maintain a high population growth rate. With low heterogeneity and little effects of orphaning on juvenile mortality, however, random harvest had a lower impact on population growth than selective harvest. Over the long term, selective female harvest may increase the proportion of successful reproducers in the population.

Synthesis and applications. Selective harvests of non‐lactating females appear justified only if female heterogeneity in reproductive potential and/or orphan mortality are very high. Because pre‐reproductive females will be subject to intense harvest, selective harvest may reduce population growth rate compared to random harvest in species with late primiparity, especially if most pre‐reproductive female normally survive to primiparity. When heterogeneity in reproductive potential and orphan mortality are low, random female harvest appears preferable to selective harvest.
General allometric scaling of net primary production agrees with plant adaptive strategy theory and has tipping points
Authors: Jenkins David G. , Pierce Simon 
Published: December 2016

SummaryAllometric scaling of net primary production (NPP) with plant biomass (B) is important to ecological carbon dynamics and energetics. Metabolic theory predicts a nonlinear power law forNPPscaling, based on fractal vascular systems, resulting in a linear model when using logNPP/log B axes that are standard in allometry. Alternatively, two other hypotheses predict nonlinear models for log‐transformed data, with potential tipping points. Size‐based competition may cause a quadratic curve as larger plants limitNPPby smaller plants. More inclusively, the plant adaptive strategies hypothesis predicts a sigmoidal curve to represent those same competitive effects, plus stress and ruderal adaptations that maintain relatively lowNPPin habitats that are abiotically limiting or disturbed.We evaluated all three hypotheses for terrestrial vascular plants, using information theoretic model selection based on the Akaike Information Criterion (AICc). Published data (N = 709) were organised in subsets according to reported organisational level and plant growth form. Alternative curves were compared for a general model (using all data) and per subset. Potential tipping points were estimated using segmented regression.The plant adaptive strategies hypothesis was supported in general (AICc weight = 1·00) and via internal consistency for five of six subsets (86% of data). Competition was supported as affectingNPPat greater B, where quadratic and sigmoidal models often coincided. Only non‐woody assemblages most plausibly fit a power law model, perhaps related to sparse data at lowest B.Synthesis. Adaptive strategies and corresponding environmental conditions appear to constrain terrestrial net primary production scaling relative to metabolic theory's ideal. Moreover, tipping points in general nonlinear net primary production scaling (at c. 38 and 360 g m−2B) indicate thresholds for rapid changes in net primary production given changing B that occurs via changing climate, human appropriation and land use.
Species interactions increase the temporal stability of community productivity in Pinus sylvestris–Fagus sylvatica mixtures across Europe
Authors: del Río Miren , Pretzsch Hans , Ruíz‐Peinado Ricardo , Ampoorter Evy , Annighöfer Peter , Barbeito Ignacio , Bielak Kamil , Brazaitis Gediminas , Coll Lluís , Drössler Lars , Fabrika Marek , Forrester David I. , Heym Michael , Hurt Václav , Kurylyak Viktor , Löf Magnus , Lombardi Fabio , Madrickiene Ekaterina , Matović Bratislav , Mohren Frits , Motta Renzo , den Ouden Jan , Pach Maciej , Ponette Quentin , Schütze Gerhard , Skrzyszewski Jerzy , Sramek Vit , Sterba Hubert , Stojanović Dejan , Svoboda Miroslav , Zlatanov Tzvetan M. , Bravo‐Oviedo Andrés 
Published: December 2016

Summary

There is increasing evidence that species diversity enhances the temporal stability (TS) of community productivity in different ecosystems, although its effect at the population and tree levels seems to be negative or neutral. Asynchrony in species responses to environmental conditions was found to be one of the main drivers of this stabilizing process. However, the effect of species mixing on the stability of productivity, and the relative importance of the associated mechanisms, remain poorly understood in forest communities.

We investigated the way mixing species influenced the TS of productivity in Pinus sylvestris L. and Fagus sylvatica L. forests, and attempted to determine the main drivers among overyielding, asynchrony between species annual growth responses to environmental conditions, and temporal shifts in species interactions. We used a network of 93 experimental plots distributed across Europe to compare the TS of basal area growth over a 15‐year period (1999–2013) in mixed and monospecific forest stands at different organizational levels, namely the community, population and individual tree levels.

Mixed stands showed a higher TS of basal area growth than monospecific stands at the community level, but not at the population or individual tree levels. The TS at the community level was related to asynchrony between species growth in mixtures, but not to overyielding nor to asynchrony between species growth in monospecific stands. Temporal shifts in species interactions were also related to asynchrony and to the mixing effect on the TS.

Synthesis. Our findings confirm that species mixing can stabilize productivity at the community level, whereas there is a neutral or negative effect on stability at the population and individual tree levels. The contrasting findings regarding the relationships between the temporal stability and asynchrony in species growth in mixed and monospecific stands suggest that the main driver in the stabilizing process may be the temporal niche complementarity between species rather than differences in species’ intrinsic responses to environmental conditions.
Neither ‘foolish’ nor ‘finished’: identity control among older adults with HIV in rural Malawi
Authors: Freeman Emily 
Published: December 2016

AbstractPrevalence of HIV after age 50 is considerable, especially in southern Africa. Negative social constructions of HIV in older age, and the health consequences of ageing with the virus, mean that having HIV presents a challenge for many people's roles and social memberships, threatening to disrupt their sense of self. Using constructivist grounded theory and qualitative data from rural Malawi, this paper describes how older men and women deal with these identity challenges. Drawing on a symbolic interactionist framework, it uses identity control theory to explore how the study's participants presented their post‐diagnosis behaviours in ways that maintained their most significant pre‐diagnosis identities as ‘adults’, a label they gave to the core identity of being a person who belongs in the social world. Considering the processes through which older people with HIV navigated challenges to their identities in light of the intersectional influences of HIV and age‐related stigma and illness, provides insight into how older people might experience HIV, as well as informing theoretical understandings of identity formation and maintenance in light of chronic and/or stigmatising illness more broadly.