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1.
Ecol Evol ; 13(2): e9803, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36789333

RESUMO

Fire affects many critical ecological processes, including pollination, and effects of climate change on fire regimes may have profound consequences that are difficult to predict. Considerable work has examined effects of fire on pollinator diversity, but relatively few studies have examined these effects on interaction networks including those of pollinators other than bees. We examined the effects of a severe wildfire on hoverfly pollinators in a Mediterranean island system. Using data collected over 3 consecutive years at burnt and unburnt sites, we documented differences in species diversity, abundance, and functional traits, as well as hoverfly interactions with flowering plants. Hoverfly abundance and species richness peaked during the first post-fire flowering season (year 1), which coincided with the presence of many opportunistic species. Also in year 1, hoverfly pollination networks were larger, less specialized, more nested, and less modular at burnt (vs. unburnt) sites; furthermore, these networks exhibited higher phylogenetic host-plant diversity. These effects declined over the next 2 years, with burnt and unburnt sites converging in similarity to hoverfly communities and interaction networks. While data obtained over 3 years provide a clear timeline of initial post-fire recovery, we emphasize the importance of longer-term monitoring for understanding the responses of natural communities to wildfires, which are projected to become more frequent and more destructive in the future.

2.
Sci Total Environ ; 747: 141197, 2020 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-32777499

RESUMO

Hyperaccumulation describes plants' ability to take up high amounts of soil metals such as Ni and allocate them to aboveground tissues. Little is known, however, about the rate at which Ni is allocated to different plant parts, or about the consumers related to these parts, including their pollinator mutualists. In this study, we examine the interface between the serpentine endemic Ni-hyperaccumulator Odontarrhena lesbiaca and its consumers of different plant parts: leaves (consumers), floral parts (consumers and primitive pollinators), and floral rewards (true pollinators). The study was conducted at two serpentine areas on Lesvos, Greece. Over 13 rounds of sampling during the flowering period of O. lesbiaca in both areas we collected plant stems with flowers, consumers of different plant parts, and flower visitors. Collected animals were mainly insects and some spiders. Chemical analyses showed negligible Ni-concentration differences between the two areas. Among all plant parts, the lowest Ni concentration was found in pollen and the highest in leaves. Regarding animal dietary habits, folivores accumulated the highest Ni concentrations, therefore characterized as "high-Ni insects", while floral-reward consumers, both primary (bees) and secondary (Eristalis tenax, Pygopleurus spp., and wasps), bore low Ni loads. Ni-body load of predators that fed on animals that were passing by was also low. Among floral-reward consumers, short-range fliers (bees of the genera Andrena and Lasioglossum) accumulated higher Ni loads than long-range fliers (Apis mellifera, Bombus terrestris, Eristalis tenax). Solitary Andrena bees accumulated higher Ni concentration than eusocial honeybees (Apis mellifera) and bumblebees (Bombus terrestris); a group of Lasioglossum specimens encompassing both solitary and eusocial bees lay in between. Our results show that diet, foraging distance, and sociality are important factors for Ni transferred into consumers and mutualists, mostly insects that are directly associated with different plant parts of O. lesbiaca.


Assuntos
Brassicaceae , Níquel , Animais , Abelhas , Bioacumulação , Flores , Grécia , Humanos , Polinização
3.
Ecology ; 100(3): e02615, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30786023

RESUMO

Fire, a frequent disturbance in the Mediterranean, affects pollinator communities. We explored the response of major pollinator guilds to fire severity, across a fire-severity gradient at different spatial scales. We show that the abundance of all pollinator groups responded to fire severity, and that bees and beetles showed in addition a significant species-diversity response. Bees, sawflies, and wasps responded to fire severity at relatively small spatial scales (250-300 m), whereas flies and beetles responded at larger spatial scales. The response of bees, sawflies, and wasps was unimodal, as predicted by the intermediate disturbance hypothesis, whereas flies and beetles showed a negative response. A possible explanation is that the observed patterns (spatial scale and type of response) are driven by taxa-specific ecological and life-history traits, such as nesting preference and body size, as well as the availability of resources in the postfire landscape. Our observational study provides an insight into the effect of fire severity on pollinators. However, future research exploring the explicit link between the pre- and postfire landscape structure and pollinator traits and responses is required for further establishment and understanding of cause-effect relationships.


Assuntos
Besouros , Incêndios , Pinus , Animais , Abelhas , Ecologia , Florestas
4.
Hellenic J Cardiol ; 60(4): 241-246, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-29890282

RESUMO

OBJECTIVE: Angina is an important clinical symptom indicating underlying coronary artery disease (CAD). Its characteristics are important for the diagnosis and risk stratification of patients with CAD. Currently, we aimed to investigate the association of chest pain characteristics with the presence of obstructive CAD in a contemporary cohort of patients undergoing coronary angiography for suspected stable CAD. METHODS: Consecutive patients undergoing coronary angiography for suspected stable CAD (n = 686) in a single university hospital cardiology department were enrolled. Chest pain was classified as typical angina, atypical angina, nonangina chest pain, and lack of symptoms. The presence of significant angiographic CAD was diagnosed by standard coronary angiography. RESULTS: Typical angina symptoms were associated with a higher prevalence of CAD (odds ratio [OR], 3.47, p < 0.001), whereas atypical angina symptoms were associated with a lower prevalence of CAD (OR, 0.49, p = 0.003) than the nonangina symptoms/or asymptomatic status. In multivariate analysis, typical angina symptoms remained an independent predictor of CAD (OR, 2.54, p < 0.001), with a greater predictive accuracy than other clinical risk factors (area under the curve [AUC], 0.715, p < 0.001) and similar to the accuracy of the high-sensitivity C-reactive protein (AUC, 0.712, p < 0.001). In a multivariate model, the combination of all studied factors further improved the predictive accuracy (AUC, 0.81, p < 0.001). CONCLUSION: In a contemporary cohort of patients referred for coronary angiography for stable CAD, the presence of typical angina symptoms was the most important independent predictor of obstructive CAD. The association of atypical angina symptoms with low CAD prevalence compared to nonangina chest pain or absence of significant symptoms probably reflects different management and referral strategies in these groups of patients.


Assuntos
Angina Pectoris/classificação , Angina Pectoris/etiologia , Dor no Peito/diagnóstico , Constrição Patológica/patologia , Doença da Artéria Coronariana/diagnóstico por imagem , Idoso , Angina Pectoris/diagnóstico , Proteína C-Reativa/análise , Dor no Peito/classificação , Regras de Decisão Clínica , Comorbidade , Angiografia Coronária/métodos , Doença da Artéria Coronariana/epidemiologia , Doença da Artéria Coronariana/fisiopatologia , Feminino , Humanos , Inflamação/sangue , Masculino , Pessoa de Meia-Idade , Prevalência , Estudos Prospectivos , Fatores de Risco
5.
Ecol Appl ; 26(3): 796-807, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27411251

RESUMO

The structure of pollination networks is an important indicator of ecosystem stability and functioning. Livestock grazing is a frequent land use practice that directly affects the abundance and diversity of flowers and pollinators and, therefore, may indirectly affect the structure of pollination networks. We studied how grazing intensity affected the structure of plant-flower visitor networks along a wide range of grazing intensities by sheep and goats, using data from 11 Mediterranean plant-flower visitor communities from Lesvos Island, Greece. We hypothesized that intermediate grazing might result in higher diversity as predicted by the Intermediate Disturbance Hypothesis, which could in turn confer more stability to the networks. Indeed, we found that networks at intermediate grazing intensities were larger, more generalized, more modular, and contained more diverse and even interactions. Despite general responses at the network level, the number of interactions and selectiveness of particular flower visitor and plant taxa in the networks responded differently to grazing intensity, presumably as a consequence of variation in the abundance of different taxa with grazing. Our results highlight the benefit of maintaining moderate levels of livestock grazing by sheep and goats to preserve the complexity and biodiversity of the rich Mediterranean communities, which have a long history of grazing by these domestic animals.


Assuntos
Flores , Herbivoria , Insetos/fisiologia , Gado/fisiologia , Plantas/classificação , Polinização , Animais , Ecossistema , Monitoramento Ambiental , Grécia , Ilhas do Mediterrâneo
7.
J Clin Med Res ; 7(1): 65-8, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25368707

RESUMO

Natalizumab (NTM) represents an effective drug for the treatment of relapsing-remitting multiple sclerosis (RRMS). Progressive multifocal leucoencephalopathy (PML) is a potential life-threatening complication of NTM treatment. A close follow-up and MRI monitoring of patients under NTM are required to avoid such devastating complications. The case of a 47-year-old woman with RRMS (EDSS 1.5) treated with NTM for 44 months is reported. The patient had a relapse with mild cerebellar symptomatology and visual complaints. MRI revealed a new area of abnormal signal intensity in the subcortical white matter of the right parietal lobe with mild peripheral enhancement. Visual fields showed scotomata mostly of the left eye. NTM was discontinued. JC virus (JCV) polymerase chain reaction (PCR) in cerebrospinal fluid was negative. The patient received IV corticosteroids for 5 days and then monthly for 2 months with subsequent clinical and MRI improvement. On month 4, she presented with a new relapse with severe ataxia, mild behavioral change, increase of cerebellar symptoms and internuclear opthalmoplegia (EDSS 3.5). MRI showed reappearance of the right parietal lobe lesion, with decreased size and less pronounced contrast enhancement. A new 2-cm lesion was noted in the left cerebellar hemisphere with a speckled pattern of contrast enhancement. JCV PCR was negative and the patient was treated with IV corticosteroids. On month 12, she demonstrated clinical and MRI improvement. Although initially PML was highly suspected in this patient, the clinical and MRI findings were supportive of the presence of immune reconstitution inflammatory syndrome (IRIS).

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