2,505 research outputs found
Birds adapted to cold conditions show greater changes in range size related to past climatic oscillations than temperate birds
Investigation of ecological responses of species to past climate oscillations provides crucial information to understand the effects of global warming. In this work, we investigated how past climate changes affected the distribution of six bird species with different climatic requirements and migratory behaviours in the Western Palearctic and in Africa. Species Distribution Models and Marine Isotopic Stage (MIS) 2 fossil occurrences of selected species were employed to evaluate the relation between changes in range size and species climatic tolerances. The Last Glacial Maximum (LGM) range predictions, generally well supported by the MIS 2 fossil occurrences, suggest that cold-dwelling species considerably expanded their distribution in the LGM, experiencing more pronounced net changes in range size compared to temperate species. Overall, the thermal niche proves to be a key ecological trait for explaining the impact of climate change in species distributions. Thermal niche is linked to range size variations due to climatic oscillations, with cold-adapted species currently suffering a more striking range reduction compared to temperate species. This work also supports the persistence of Afro-Palearctic migrations during the LGM due to the presence of climatically suitable wintering areas in Africa even during glacial maxim
Vrba was right: historical climate fragmentation, and not current climate, explains mammal biogeography
Climate plays a crucial role in shaping species distribution and evolution over time. Dr Vrba's Resource‐Use hypothesis posited that zones at the extremes of temperature and precipitation conditions should host a greater number of climate specialist species than other zones because of higher historical fragmentation. Here, we tested this hypothesis by examining climate‐induced fragmentation over the past 5 million years. Our findings revealed that, as stated by Vrba, the number of climate specialist species increases with historical regional climate fragmentation, whereas climate generalist species richness decreases. This relationship is approximately 40% stronger than the correlation between current climate and species richness for climate specialist species and 77% stronger for generalist species. These evidences suggest that the effect of climate historical fragmentation is more significant than that of current climate conditions in explaining mammal biogeography. These results provide empirical support for the role of historical climate fragmentation and physiography in shaping the distribution and evolution of life on Earth.Agencia Estatal de Investigación | Ref. PID2021-123202NA-I00Universidade de Vigo/CISU
No bird database is perfect: citizen science and professional datasets contain different and complementary biodiversity Information
Citizen science has become a powerful tool for collecting big data on biodiversity. However, concerns have been raised about potential biases in these new datasets. We aimed to test whether citizen science bird databases have more biases than professional scientific databases. Our hypotheses were 1) citizen science databases will have more data on “easy to spot” species, that are widely distributed and have large body sizes; whereas 2) professional databases will have more endangered species and species of special interest for research. We analysed six Spanish bird databases: three professional, two citizen science and one mixed database. Our results show that, in general, occurrences in citizen science databases are better explained by the studied variables than professional databases, but no clear differences were found when analysed individually. Both citizen science and professional databases contain invaluable information on biodiversity but every database comes with a particular history and its stored data is the result of years of field sampling with heterogeneous goals, sampling methods and sampling effort. Consequently, raw observations should not be used directly as an ideal survey of the distribution or abundance of birds. We need to uncover these biases and develop new methods to properly incorporate the extensive and heterogeneous biodiversity data that is readily available to research. Galván, S., Barrientos, R. & Varela, S. (2022). No bird database is perfect: citizen science and professional datasets contain different and complementary biodiversity information. Citizen science has become a powerful tool for collecting big data on biodiversity. However, concerns have been raised about potential biases in these new datasets. We aimed to test whether citizen science bird databases have more biases than professional scientific databases. Our hypotheses were 1) citizen science databases will have more data on “easy to spot” species, that are widely distributed and have large body sizes; whereas 2) professional databases will have more endangered species and species of special interest for research. We analysed six Spanish bird databases: three professional, two citizen science and one mixed database. Our results show that, in general, occurrences in citizen science databases are better explained by the studied variables than professional databases, but no clear differences were found when analysed individually. Both citizen science and professional databases contain invaluable information on biodiversity but every database comes with a particular history and its stored data is the result of years of field sampling with heterogeneous goals, sampling methods and sampling effort. Consequently, raw observations should not be used directly as an ideal survey of the distribution or abundance of birds. We need to uncover these biases and develop new methods to properly incorporate the extensive and heterogeneous biodiversity data that is readily available to research. Galván, S., Barrientos, R. & Varela, S. (2022). No bird database is perfect: citizen science and professional datasets contain different and complementary biodiversity information. Ardeola, 69: 97-114La ciencia ciudadana se ha convertido en una poderosa herramienta para recopilar datos sobre biodiversidad. Sin embargo, a pesar de su disponibilidad para ser utilizados en investigaciones
científicas, sus posibles sesgos se encuentran bajo continuo debate. Por ello, en este trabajo pretendemos comprobar si estas bases de datos sobre avifauna de España presentan mayores sesgos que
aquellas científico-profesionales. Nuestras hipótesis son: 1) las bases de datos ciudadanas recogerán un mayor número de aves “fáciles de detectar” (ampliamente distribuidas y con mayores tamaños corporales), mientras que 2) las bases de datos profesionales recogerán preferentemente especies en peligro de extinción o con algún interés científico específico. Para comprobarlo, analizamos seis bases de
datos: tres profesionales, dos ciudadanas y una mixta. Nuestros resultados mostraron que, en general, las variables estudiadas explican mejor las observaciones de las bases de datos ciudadanas en comparación con aquellas de las bases de datos profesionales, aunque no se encontraron diferencias claras
cuando se analizaron individualmente. Así, tanto las bases de datos ciudadanas como las profesionales poseen una información muy valiosa sobre biodiversidad, aunque cada una de ellas posee una historia
particular y su información es el resultado de años de muestreo con objetivos, métodos y esfuerzos heterogéneos. En consecuencia, sus observaciones no deben utilizarse directamente como un reflejo
ideal de la distribución o la abundancia de estas aves. Así, es necesario detectar estos sesgos y desarrollar nuevos métodos para incorporar esta gran cantidad de datos sobre biodiversidad en futuras investigaciones. Galván, S., Barrientos, R. y Varela, S. (2022). Las bases de datos de ciencia ciudadana y profesionales poseen información diferente y complementaria sobre la avifauna. Ardeola, 69: 97-11
Climate change and the increase of human population will threaten conservation of Asian cobras
Asian cobras (genus Naja) are venomous snakes distributed from the Middle East to Southeast Asia.
Because cobras often live near humans settlements, they are responsible for a large part of snakebite
incidents and as such pose a challenge for public health systems. In the light of growing human
populations, correctly mapping the present and future ranges of Asian cobras is therefore important
for both biological conservation and public health management. Here, we mapped the potential
climatic niches of ten Asian cobra species for both the present and the future, with the aim to quantify
changes in climate and human population densities relative to their current and future ranges. Our
analyses reveal that cobras that are adapted to dry climates and inhabit islands have narrow climatic
niches, while those of mainland species with larger geographic ranges are much wider. We also found
a higher degree of fragmentation of future cobra distributions; within the next 50 years, Asian cobras
will lose an average of around 60% of their current suitable climatic range. In the near future, Naja
mandalayensis, N. sputatrix, N. samarensis, and N. philippinensis are likely to have no accessible
suitable climate space left. Besides, a further increase of human populations in this region may also
exponentially accelerate the effects of anthropogenic impacts. Solutions for conservation may involve
awareness and appropriate use of law to overcome the rate of habitat degradation and the increase
of animal trade of Asian cobras, while promoting investment on health systems to avoid snakebite
fatalities.German Academic Exchange Service | Ref. 9160910
Climatic constraints on the biogeographic history of Mesozoic dinosaurs
Dinosaurs dominated Mesozoic terrestrial ecosystems globally. However, whereas a pole-to-pole geographic distribution characterized ornithischians and theropods, sauropods were restricted to lower latitudes. Here, we evaluate the role of climate in shaping these biogeographic patterns through the Jurassic–Cretaceous (201–66 million years ago), combining dinosaur fossil occurrences, past climate data from Earth System models, and habitat suitability modelling. Results show that uniquely among dinosaurs, sauropods occupied climatic niches characterised by high temperatures and strongly bounded by minimum cold temperatures. This constrained the distribution and dispersal pathways of sauropods to tropical areas, excluding them from latitudinal extremes, especially in the Northern Hemisphere. The greater availability of suitable habitat in the southern continents, particularly in the Late Cretaceous, might be key to explaining the high diversity of sauropods there, relative to northern landmasses. Given that ornithischians and theropods show a flattened or bimodal latitudinal biodiversity gradient, with peaks at higher latitudes, the closer correspondence of sauropods to a subtropical concentration could hint at fundamental thermophysiological differences to the other two clades
Future climate change will impact the migration of New World migrant flycatchers (Tyrannidae)
Climate change is reaching several tipping points, likely resulting in habitat shifts at a global scale. Such changes could have serious consequences for migratory species. For instance, climatic changes may impact the distribution of breeding and non-breeding ranges, resulting in longer migration distances for some species. The flycatchers (Tyrannidae) are the largest family of birds in New World. They are small insectivorous birds with different distributions and migratory strategies, including both tropical and temperate species. Here, we aim to map the climatically suitable ranges for Tyrannidae in the future, compare them to their present ranges, and quantify the changes in range size and in migratory distance. We show different impacts on species that breed in the northern vs. southern hemisphere. Furthermore, results suggest that tropical and temperate species would suffer from different stressors. Neotropical austral migrant species would lose part of their breeding ranges, while Nearctic-Neotropical species would need to fly longer distances to reach the same climatic conditions of their current breeding ranges. Because past climate shifts have shaped the evolution of bird migration, these insights are also key for elucidating the mechanisms underlying the evolution and regulation of bird migration, and for conservation planning.conselho nacional de desenvolvimento científico e tecnológic
Mammal traits and soil biogeochemistry: Functional diversity relates to composition of soil organic matter
Mammal diversity affects carbon concentration in Amazonian soils. It is known that some species traits determine carbon accumulation in organisms (e.g., size and longevity), and are also related to feeding strategies, thus linking species traits to the type of organic remains that are incorporated into the soil. Trait diversity in mammal assemblages – that is, its functional diversity – may therefore constitute another mechanism linking biodiversity to soil organic matter (SOM) accumulation. To address this hypothesis, we analyzed across 83 mammal assemblages in the Amazon biome (Guyana), the elemental (by ED‐XRF and CNH analysis) and molecular (FTIR‐ATR) composition of SOM of topsoils (401 samples) and trait diversity (functional richness, evenness, and divergence) for each mammal assemblage. Lower mammal functional richness but higher functional divergence were related to higher content of carbonyl and aliphatic SOM, potentially affecting SOM recalcitrance. Our results might allow the design of biodiversity management plans that consider the effect of mammal traits on carbon sequestration and accumulation in soils.Xunta de Galicia | Ref. ED431C 2021/32Xunta de Galicia | Ref. ED481D 2019/024National Science Foundation | Ref. BE/CNH 05 0809
Mammal and tree diversity accumulate different types of soil organic matter in the northern Amazon
Diversity of plants and animals influence soil carbon through their contributions
to soil organic matter (SOM). However, we do not know whether mammal and
tree communities affect SOM composition in the same manner. This question is
relevant because not all forms of carbon are equally resistant to mineralization
by microbes and thus, relevant to carbon storage. We analyzed the elemental
and molecular composition of 401 soil samples, with relation to the species richness
of 83 mammal and tree communities at a landscape scale across 4.8 million
hectares in the northern Amazon. We found opposite effects of mammal and
tree richness over SOM composition. Mammal diversity is related to SOM rich
in nitrogen, sulfur and iron whereas tree diversity is related to SOM rich in
aliphatic and carbonyl compounds. These results help us to better understand
the role of biodiversity in the carbon cycle and its implications for climate change
mitigation.Xunta de Galicia | ED481D 2019/024Xunta de Galicia | ED431C2021/32European Commission | Ref. H2020, n. 947921National Science Foundation (NSF) | BE/CNH 05 0809
A predominant involvement of the triple seropositive patients and others with rheumatoid factor in the association of smoking with rheumatoid arthritis
The major environmental risk factor for rheumatoid arthritis (RA) is smoking, which according to a widely accepted model induces protein citrullination in the lungs, triggering the production of anticitrullinated protein antibodies (ACPA) and RA development. Nevertheless, some research findings do not fit this model. Therefore, we obtained six independent cohorts with 2253 RA patients for a detailed analysis of the association between smoking and RA autoantibodies. Our results showed a predominant association of smoking with the concurrent presence of the three antibodies: rheumatoid factor (RF), ACPA and anti-carbamylated protein antibodies (ACarPA) (3 Ab vs. 0 Ab: OR = 1.99, p = 2.5 × 10?8). Meta-analysis with previous data (4491 patients) confirmed the predominant association with the concurrent presence of the three antibodies (3 Ab vs. 0 Ab: OR = 2.00, p = 4.4 ×10?16) and revealed that smoking was exclusively associated with the presence of RF in patients with one or two antibodies (RF+ 1+2 vs. RF? 0+1+2: OR = 1.32, p = 0.0002). In contrast, no specific association with ACPA or ACarPA was found. Therefore, these results showed the need to understand how smoking favors the concordance of RA specific antibodies and RF triggering, perhaps involving smoking-induced epitope spreading and other hypothesized mechanisms
Breast cancer patient’s outcomes after neoadjuvant chemotherapy and surgery at 5 and 10 years for stage II–III disease
Introduction: Neoadjuvant chemotherapy in breast cancer offers the possibility to facilitate breast and axillary surgery; it is a test of chemosensibility in vivo with significant prognostic value and may be used to tailor adjuvant treatment according to the response. Material and Methods: A retrospective single-institution cohort of 482 stage II and III breast cancer patients treated with neoadjuvant chemotherapy based on anthracycline and taxans, plus antiHEr2 in Her2-positive cases, was studied. Survival was calculated at 5 and 10 years. Kaplan-Meier curves with a log-rank test were calculated for differences according to age, BRCA status, menopausal status, TNM, pathological and molecular surrogate subtype, 20% TIL cut-off, surgical procedure, response to chemotherapy and the presence of vascular invasion. Results: The pCR rate was 25.3% and was greater in HER2 (51.3%) and TNBC (31.7%) and in BRCA carriers (41.9%). The factors independently related to patient survival were pathology and molecular surrogate subtype, type of surgery, response to NACT and vascular invasion. BRCA status was a protective prognostic factor without reaching statistical significance, with an HR 0.5 (95%CI 0.1-1.4). Mastectomy presented a double risk of distant recurrence compared to breast-conservative surgery (BCS), supporting BCS as a safe option after NACT. After a mean follow-up of 126 (SD 43) months, luminal tumors presented a substantial difference in survival rates calculated at 5 or 10 years (81.2% compared to 74.7%), whereas that for TNBC was 75.3 and 73.5, respectively. The greatest difference was seen according to the response in patients with pCR, who exhibited a 10 years DDFS of 95.5% vs. 72.4% for those patients without pCR, p < 0001. This difference was especially meaningful in TNBC: the 10 years DDFS according to an RCB of 0 to 3 was 100%, 80.6%, 69% and 49.2%, respectively, p < 0001. Patients with a particularly poor prognosis were those with lobular carcinomas, with a 10 years DDFS of 42.9% vs. 79.7% for ductal carcinomas, p = 0.001, and patients with vascular invasion at the surgical specimen, with a 10 years DDFS of 59.2% vs. 83.6% for those patients without vascular invasion, p < 0.001. Remarkably, BRCA carriers presented a longer survival, with an estimated 10 years DDFS of 89.6% vs. 77.2% for non-carriers, p = 0.054. Conclusions: Long-term outcomes after neoadjuvant chemotherapy can help patients and clinicians make well-informed decisions
- …