In this study, we aim to gain a better insight on how habitat filtering due to urbanization shapes bird communities of Vienna city parks. This may help to derive implications for urban planning in ...order to promote and maintain high diversity and ecosystem function in an increasing urbanized environment. The structure of wintering bird communities of 36 Vienna city parks – surveyed once a month in January 2009, December 2009, December 2012, and January 2013 – was described by species richness and the functional diversity measurements FRic (functional richness), FEve (functional evenness), and FDiv (functional divergence). Environmental filtering was quantified by park size, canopy heterogeneity within the park, and the proportion of sealed area surrounding each park. Species richness, FRic, and FDiv increased with increasing park size. Sealed area had a strong negative effect on species richness and FDiv. Canopy heterogeneity played a minor role in explaining variance in FDiv data. FEve did not respond to any of these park parameters. Our results suggest a loss of species richness and functional diversity, hence most likely indicate a decline in ecosystem function, with decreasing park size and increasing sealed area of the surrounding urban landscape matrix.
The functional diversity of wintering bird communities in city parks of Vienna was quantified to gain a better insight on how habitat filtering due to urbanisation shapes bird communities. Environmental filtering was quantified by park size, canopy heterogeneity within the park and the proportion of sealed area surrounding each park. Our results suggest a loss of species richness and functional diversity, hence most likely indicate a decline in ecosystem function, with decreasing park size and increasing sealed area of the surrounding urban landscape matrix.
Local and landscape-scale agricultural intensification is a major driver of global biodiversity loss. Controversially discussed solutions include wildlife-friendly farming or combining high-intensity ...farming with land-sparing for nature. Here, we integrate biodiversity and crop productivity data for smallholder cacao in Indonesia to exemplify for tropical agroforests that there is little relationship between yield and biodiversity under current management, opening substantial opportunities for wildlife-friendly management. Species richness of trees, fungi, invertebrates, and vertebrates did not decrease with yield. Moderate shade, adequate labor, and input level can be combined with a complex habitat structure to provide high biodiversity as well as high yields. Although livelihood impacts are held up as a major obstacle for wildlife-friendly farming in the tropics, our results suggest that in some situations, agroforests can be designed to optimize both biodiversity and crop production benefits without adding pressure to convert natural habitat to farmland.
Beyond preferences for particular species of tree, bark-foraging birds are associated with various tree characteristics such as decay stage, trunk diameter, or bark roughness. Our objectives were to ...study the winter foraging ecology of different bark-foraging bird species in the highly diverse floodplain forests of Donau-Auen National Park (Austria) by examining the importance of tree species and characteristics. We used 'first-foraging' observations on the great spotted woodpecker (
Dendrocopos major
), middle spotted woodpecker (
Leiopicus medius
), Eurasian nuthatch (
Sitta europaea
), treecreepers (
Certhia
spp.), great tit (
Parus major
), Eurasian blue tit (
Cyanistes caeruleus
), and marsh tit (
Poecile palustris
). We examined bird-tree relationships with a bird-plant network approach, where we compared traits of trees and their preferences among avian species. The five most important tree species relative to distance-weighted fragmentation were European white elm (
Ulmus laevis
), pedunculate oak (
Quercus robur
), common ash (
Fraxinus excelsior
), and white and black poplar (
Populus alba, P. nigra
). Avian taxa differed only in the use of tree condition, where woodpeckers used decayed and dead trees more than tits. Most species preferred trees of larger trunk diameter with rougher bark. We suspect that changes in these highly diverse floodplain forest stands will eventually lead to changes in bark-foraging bird assemblages. For the protection of such highly diverse floodplain forests, conservation-based water management practices will be crucial to maintaining a sufficient groundwater table. Our findings also suggest that forest management practices should focus on more diverse commercial forest stands with a critical amount of secondary tree species, a variety of size classes, varying tree conditions, and species with different bark roughness classes.
Habitat loss and degradation are key drivers of the current biodiversity crisis. Most research focuses on the question of which traits allow species to persist in degraded habitats. We asked whether ...a species' trophic position or niche width influences the resilience of species in degraded habitats and to what extent habitat degradation affects trophic interactions between species. We used nitrogen isotope ratios (15N:14N, expressed as δ15N value) to quantify and compare trophic positions and niche widths of understory birds inhabiting old‐growth and young secondary forests in the Pacific lowlands of Costa Rica. We found that a species' trophic position rather than its trophic niche width determined its persistence in secondary forests. Species feeding at lower trophic levels in old‐growth forests were less likely to persist in secondary forests than those occupying a higher trophic position in old‐growth forests. This pattern is likely induced by the occurrence of relatively large‐bodied habitat specialists with a flexible and high‐trophic level diet in secondary forests. These habitat specialists likely caused generalist bird species to lower their trophic position relative to conspecifics in old‐growth forests. Regarding trophic niche widths, species in secondary forests tend to have larger niche widths than old‐growth forest species. However, as old‐growth forest specialists and generalists did not differ in their niche widths, no systematic effect of trophic niche width on species persistence after forest disturbance was found. This is the first study that shows a systematic effect of trophic position on the persistence of a wide range of bird species in a disturbed forest ecosystem. It therefore provides important insights into species' responses to habitat degradation and the conservation value of secondary forests. To improve habitat quality for old‐growth forest birds and facilitate avian seed dispersal, the creation of large contiguous forest patches should be prioritised when implementing reforestation measures.
We studied whether an understory bird species' trophic position or niche width determines its persistence after forest disturbance in the Pacific lowlands of Costa Rica. Using stable isotope methodology, we found a significant effect of trophic position: Species feeding at low trophic levels in old‐growth forests were less likely to persist in secondary forests. The dataset provides insights into species' responses to habitat degradation and the conservation value of the secondary forests in the study area, which are useful for planning of future conservation measures in the region.
The female sex in honeybees (Apis spp.) comprises a reproductive queen and a sterile worker caste. Nurse bees feed all larvae progressively with a caste-specific food jelly until the prepupal stage. ...Only those larvae that are exclusively fed a large amount of royal jelly (RJ) develop into queens 1. RJ is a composite secretion of two specialized head glands: the mandibular glands, which produce mainly fatty acids 2, and the hypopharyngeal glands, which contribute proteins, primarily belonging to the major royal jelly protein (MRJP) family 3. Past research on RJ has focused on its nutritional function and overlooked its central role with regard to the orientation of the larva in the royal brood cell. Whereas workers are reared in the regular horizontal cells of the comb, the queen cells are specifically built outside of the normal comb area to accommodate for the larger queen 4, 5. These cells hang freely along the bottom of the comb and are vertically oriented, opening downward 6. Queen larvae are attached by their RJ diet to the cell ceiling. Thus, the physical properties of RJ are central to successful retention of larvae in the cell. Here, we show that the main protein of RJ (MRJP1) polymerizes in complex with another protein, apisimin, into long fibrous structures that build the basis for the high viscosity of RJ to hold queen larvae on the RJ surface.
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•Royal jelly ensures queen-bee development also by physical properties•High-royal-jelly viscosity holds the queen larvae in place•Nurse bees combine secretions of two head glands to ensure the high viscosity•A fibril network of two proteins determines royal jelly viscosity
Honeybee queen larvae are raised in specific cells which are vertically oriented, opening downwards. Nurse bees deposit protein rich royal jelly at the cell ceiling as larval food. Buttstedt et al. show that two of these proteins are crucial for queen development. They control royal jelly viscosity, preventing the larva to fall out of its cell.
Tropical species are considered to be more threatened by climate change than those of other world regions. This increased sensitivity to warming is thought to stem from the assumptions of low ...physiological capacity to withstand temperature fluctuations and already living near their limits of heat tolerance under current climatic conditions. For birds, despite thorough documentation of community‐level rearrangements, such as biotic attrition and elevational shifts, there is no consistent evidence of direct physiological sensitivity to warming. In this review, we provide an integrative outlook into the physiological response of tropical birds to thermal variation and their capacity to cope with warming. In short, evidence from the literature suggests that the assumed physiological sensitivity to warming attributed to tropical biotas does not seem to be a fundamental characteristic of tropical birds. Tropical birds do possess the physiological capacities to deal with fluctuating temperatures, including high‐elevation species, and are prepared to withstand elevated levels of heat, even those living in hot and arid environments. However, there are still many unaddressed points that hinder a more complete understanding of the response of tropical birds to warming, such as cooling capacities when exposed to combined gradients of heat and humidity, the response of montane species to heat, and thermoregulation under increased levels of microclimatic stress in disturbed ecosystems. Further research into how populations and species from different ecological contexts handle warming will increase our understanding of current and future community rearrangements in tropical birds.
Emprirical data from the literature show that tropical birds are not characterized by narrow thermal tolerance and may not be physiologically threatened by global warming in the short term.
Invasive species pose a major threat to forest biodiversity, particularly on islands such as the Galapágos. Here, invasive plants are threatening the remnants of the unique cloud forest and its ...iconic Darwin's finches. We posit that food web disturbances caused by invasive Rubus niveus (blackberry), have contributed to the rapid decline of the insectivourous green warbler finch (Certhidae olivacea). We compared the birds' dietary changes in long-term management, short-term management and unmanaged areas. We measured C:N ratios, and δ15N‑nitrogen and δ13C‑carbon values in both consumer tissues (bird-blood) and food sources (arthropods), as indicators of resource use change, and collected mass abundance, and arthropod diversity data. We characterised the birds' diets using isotope mixing models. The results revealed that finches in (blackberry-invaded) unmanaged areas foraged more on abundant, yet lower quality, arthropods present in the invaded understory. This suggests that blackberry encroachment leads to a decrease in food source quality with physiological consequences for green warbler finch chicks. Results also implied that blackberry control has a short-term impact on food source quantity, which led to a decrease in chick recruitment that we observed in our previous studies; despite this, in the long-term, these managed systems show signs of recovery within three years of restoration.
Schematic of whole system. Each spot in forest represents 10 mg dry mean mass of arthropods/m2, orange-canopy, dark yellow-moss, dark green-understory (nplots = 10, round 2, 2015). Long-term management area (LTM), recently controlled area (RC), and unmanaged area (NC). Bug colour represents arthropod nutritional quality, with dark green high quality, light green lower quality. Eggs in nests indicate mean relative breeding success (Cimadom et al., 2019). Bird size highlighting lower tarsus length in NC area (but not to scale). Bar charts below indicated proportion of bird diet derived from the different strata, orange-canopy, dark yellow-moss, dark green-understory based on isotope mixing model data. Display omitted
•Blood stoichiometry and stable isotope analysis reveal dietary changes of finches.•Disturbance of Scalesia forest by blackberry invasion caused changes in bird diet.•Analysis of bird's diet & its stoichiometry, disclosed trophic ladder alterations.•Higher C:N ratios of diet, possibly reduced bird's tarsus length in invaded areas.•Stable isotope analysis useful to investigate Galápagos or conservation species.
Immune checkpoint inhibition leads to response in some patients with head and neck squamous cell carcinoma (HNSCC). Robust biomarkers are lacking to date. We analyzed viral status, gene expression ...signatures, mutational load and mutational signatures in whole exome and RNA‐sequencing data of the HNSCC TCGA dataset (n = 496) and a validation set (DKTK MASTER cohort, n = 10). Public single‐cell gene expression data from 17 HPV‐negative HNSCC were separately reanalyzed. APOBEC3‐associated TCW motif mutations but not total single nucleotide variant burden were significantly associated with inflammation. This association was restricted to HPV‐negative HNSCC samples. An APOBEC‐enriched, HPV‐negative subgroup was identified, that showed higher T‐cell inflammation and immune checkpoint expression, as well as expression of APOBEC3 genes. Mutations in immune‐evasion pathways were also enriched in these tumors. Analysis of single‐cell sequencing data identified expression of APOBEC3B and 3C genes in malignant cells. We identified an APOBEC‐enriched subgroup of HPV‐negative HNSCC with a distinct immunogenic phenotype, potentially mediating response to immunotherapy.
What's new?
Head and neck squamous cell carcinoma (HNSCC) is sometimes susceptible to immune checkpoint inhibitors, and biomarkers are needed to help identify which tumors are most likely to respond. Using the Cancer Genome Atlas, these authors evaluated 496 HSNCCs by HPV status, gene expression signatures, mutational load, and mutational signatures. They found that increased inflammation was associated with APOBEC3‐induced mutations in HPV‐negative cancers. This newly identified APOBEC‐enriched, HPV‐negative subgroup showed higher immune checkpoint expression, and also more mutations in immune‐evasion pathways, suggesting this may be a way to identify candidates for immune checkpoint inhibitor therapy.
The clinical relevance of comprehensive molecular analysis in rare cancers is not established. We analyzed the molecular profiles and clinical outcomes of 1,310 patients (rare cancers, 75.5%) ...enrolled in a prospective observational study by the German Cancer Consortium that applies whole-genome/exome and RNA sequencing to inform the care of adults with incurable cancers. On the basis of 472 single and six composite biomarkers, a cross-institutional molecular tumor board provided evidence-based management recommendations, including diagnostic reevaluation, genetic counseling, and experimental treatment, in 88% of cases. Recommended therapies were administered in 362 of 1,138 patients (31.8%) and resulted in significantly improved overall response and disease control rates (23.9% and 55.3%) compared with previous therapies, translating into a progression-free survival ratio >1.3 in 35.7% of patients. These data demonstrate the benefit of molecular stratification in rare cancers and represent a resource that may promote clinical trial access and drug approvals in this underserved patient population. SIGNIFICANCE: Rare cancers are difficult to treat; in particular, molecular pathogenesis-oriented medical therapies are often lacking. This study shows that whole-genome/exome and RNA sequencing enables molecularly informed treatments that lead to clinical benefit in a substantial proportion of patients with advanced rare cancers and paves the way for future clinical trials.
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•The city of Vienna, Austria, has a large urban Eurasian kestrel population.•Kestrels prefer breeding in roof-openings on historical buildings in the center.•Kestrels seem to hunt in their immediate ...surroundings, like backyards and city parks.•A high proportion of avian prey negatively influences breeding success.•The choice of the urban habitat is associated with reduced reproductive rates.
The urban space is a permanently changing ecosystem, suffering from decreasing biodiversity, but also providing new anthropogenic habitats for some adaptable species. The Eurasian kestrel (Falco tinnunculus) is such an adaptable species, whose dense urban populations are ethologically different from rural populations in Europe. Several studies have indicated that urban kestrels increasingly prey on birds; this study even indicated avian prey as the main prey category in the inner-city habitat. We analyzed the selection of habitat and building structure parameters while controlling for differences in their availability in Vienna, Austria, a city of 1.7 million inhabitants. We then connected the nest-site selection of urban kestrels to their diet choice and annual reproduction rate. Our results indicated a trade-off between higher nest-site availability in the center and longer distances to larger open green space as optimal foraging ground. Between 2010 and 2012, a preference for breeding in close vicinity to green backyards was linked to earlier clutch dates, higher hatching rates and larger fledged brood sizes, but the overall productivity per nest still remained low in the center compared to the suburban area. In a survey of avian prey species, we found comparable abundances of prey-sized bird species in green backyards, parks and surrounding suburban areas. We thus hypothesize that kestrels use the immediate nest-surroundings to hunt, but are not as efficient in hunting avian prey as they are in hunting voles. Changes in modern city architecture and renovation of historical buildings pose conservation related threats to urban predators and prey.
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