In this study, we hypothesized that the life history traits of Leiothrix spiralis and L. vivipara would be linked to soil factors of the rupestrian grasslands and that rosette size would be influenced by soil moisture. Soil analyses were performed from five populations of L. spiralis and four populations of L. vivipara. In each area, three replicates were employed in 19 areas of occurrence of Leiothrix species, and we quantified the life history attributes. The microhabitats of these species show low favorability regarding to soil factors. During the dry season, their rosettes decreased in diameter due the loss of its most outlying leaves. The absence of seedlings indicated the low fecundity of both species. However, both species showed rapid population growth by pseudovivipary. Both L. spiralis and L. vivipara exhibit a kind of parental care that was quantified by the presence of connections between parental-rosettes and ramets. The findings of the present study show that the life history traits are linked to soil factors.Keywords: life history, mountain habitats, pseudovivipary, soil factors; water scarcity. Efeitos de fatores do solo nos atributos de história de vida deLeiothrix spiralis e Leiothrix vivipara (Eriocaulaceae) nos campos rupestres no Sudeste do Brasil.
Herbivory is ubiquitous. Despite being a potential driver of plant distribution and performance, herbivory remains largely undocumented. Some early attempts have been made to review, globally, how much leaf area is removed through insect feeding. Kozlov et al., in one of the most comprehensive reviews regarding global patterns of herbivory, have compiled published studies regarding foliar removal and sampled data on global herbivory levels using a standardized protocol. However, in the review by Kozlov et al., only 15 sampling sites, comprising 33 plant species, were evaluated in tropical areas around the globe. In Brazil, which ranks first in terms of plant biodiversity, with a total of 46,097 species, almost half (43%) being endemic, a single data point was sampled, covering only two plant species. In an attempt to increase knowledge regarding herbivory in tropical plant species and to provide the raw data needed to test general hypotheses related to plant-herbivore interactions across large spatial scales, we proposed a joint, collaborative network to evaluate tropical herbivory. This network allowed us to update and expand the data on insect herbivory in tropical and temperate plant species. Our data set, collected with a standardized protocol, covers 45 sampling sites from nine countries and includes leaf herbivory measurements of 57,239 leaves from 209 species of vascular plants belonging to 65 families from tropical and temperate regions. They expand previous data sets by including a total of 32 sampling sites from tropical areas around the globe, comprising 152 species, 146 of them being sampled in Brazil. For temperate areas, it includes 13 sampling sites, comprising 59 species. Thus, when compared to the most recent comprehensive review of insect herbivory (Kozlov et al.), our data set has increased the base of available data for the tropical plants more than 460% (from 33 to 152 species) and the Brazilian sampling was increased 7,300% (from 2 to 146 species). Data on precise levels of herbivory are presented for more than 57,000 leaves worldwide. There are no copyright restrictions. Please cite this paper when using the current data in publications; the authors request to be informed how the data is used in the publications.
Density-dependent responses are an important component of the organism life-history, and the resource allocation theory is a central concept to the life-history theory. When resource allocation varies due to environmental changes, a plant may change its morphology or physiology to cope with the new conditions, a process known as phenotypic plasticity. Our study aimed to evaluate how plant density affects Eichhornia crassipes allocation patterns. A total of 214 individuals in high and low density were collected. The density effect was observed in all plant traits examined including biomass accumulation. All traits of E. crassipes demonstrated higher values in high density conditions, except for biomass of leaves. Density exhibited a high influence on vegetative traits of E. crassipes, but did not influence allocation pattern, since a trade-off among the vegetative traits was not found. The morphological plasticity and the a bsence of trade-offs were discussed as strategies to overcome neighbor plants in competition situations. In high density conditions, there were clear changes in the morphology of the plants which probably allows for their survival in a highly competitive environment. KEYWORDS: Phenotypic plasticity, Plant-environment relationships, Plastic morphology, Macrophyte Plasticidade morfológica dependente da densidade e compensação entre traços vegetativos em Eichhornia crassipes (Pontederiaceae) RESUMOAs respostas dependentes da densidade são um componente importante da história de vida de um organismo e a teoria da alocação de recursos é um conceito central para a teoria da história de vida. Quando a alocação de recursos varia de acordo com mudanças ambientais a planta pode alterar sua morfologia ou fisiologia para lidar com as novas condições, um processo chamado plasticidade fenotípica. Nosso estudo objetivou avaliar como a densidade de plantas afeta os padrões de alocação de Eichhornia crassipes. Foram coletadas 214 indivíduos em alta e baixa densidade. O efeito da densidade foi verificado nos traços vegetativos e na biomassa. Todas as características vegetativas medidas em E. crassipes foram maiores em condições de alta densidade com exceção da massa seca de folhas. A densidade apresentou grande influência sobre as características vegetativas de E. crassipes, mas não influenciou os padrões de alocação, já que não foram identificados 'trade-offs' entre as características vegetativas da planta.
Evolutionary theory (ET) is the unifying theory of Life Sciences, but it is largely misunderstood and the target of dispute in many countries, mainly because of conflicts with religious beliefs. Brazil is a country with a culture that is deeply rooted belief in God. In this paper, we report a study in Brazil where we applied a 12-question questionnaire to understand the relationship among the major field of study and the self-declared religious and philosophical context on the knowledge of evolutionary theory by Brazilian freshmen. We answer the following questions: (1) Is there a difference in ET comprehension according to the major field of study? (2) Are religious and philosophical contexts related to the comprehension of ET? (3) Are major field of study and religious/philosophical contexts together related to the comprehension of ET by Brazilian freshmen? A total of 153 freshmen students answered our questionnaire. Students from the Biological Sciences fared better than students from most other major field of study but were equal to students of Humanities. The philosophical perception of life had a major correlation with their knowledge about evolution, with self-declared atheists and agnostics showing better performance than religious students. There were no clear trends in the interaction of major field of study and philosophy of life. We discuss these results in the light of the rising ideological activism in Brazilian society since philosophy of life was the main driver of evolutionary theory perception. We highlight the importance of scientists and teachers in reassuring the role of science and scientific knowledge in modern societies. Supplementary Information The online version contains supplementary material available at 10.1007/s11191-021-00286-z.
Body size is one of the most important factors regarding herbaceous perennial plants life-histories, and several fitness components of these organisms are related to size. Clonal plants show distinct kinds of reproduction and can develop offspring by sexual or asexual ways. We aimed to understand how body size affects Comanthera nivea (Eriocaulaceae) sexual reproduction and to verify how clonal growth is related to flower head production in this species. We sampled 600 rosettes in rupestrian grasslands and performed linear regression analysis between body size and number of produced flower heads. We also compared the flower head production between isolated rosettes and rosettes within clones. Our results showed that body size was significantly related, but explained only a small part of flower head production. The flower head production was higher in rosettes within clones than in isolated ones. The clones presented a rosette or a small group of rosettes that concentrated the sexual reproduction. Clonality was positively associated with sexual reproduction. Clonality can represent an important way of allowing the persistence of plants by sexual reproduction in markedly seasonal stressful environments. The cases of clonality enhancing the sexual reproduction must be considered and put in focus on reproductive biology research.Keywords: body size, life history, clonality, reproductive strategies, sexual reproduction, Eriocaulaceae.Consequências do tamanho de corpo e da clonalidade para a reprodução sexuada de uma herbácea perene doa campos rupestres brasileiros Resumo O tamanho de corpo é um dos atributos de história de vida mais importantes para plantas herbáceas perenes e muitos componentes da aptidão desses organismos são relacionados ao tamanho. As plantas clonais apresentam diferentes tipos de reprodução e podem gerar prole por vias sexuadas ou assexuadas. Nosso objetivo foi compreender como o tamanho de corpo afeta a reprodução sexual em Comanthera nivea e verificar como o crescimento clonal relaciona-se à produção de capítulos dessa espécie. Nós amostramos 600 rosetas em campos rupestres e utilizamos regressões lineares para verificar a relação entre o tamanho de corpo e o número de capítulos produzidos pela planta. Nós também comparamos a produção de capítulos entre rosetas isoladas e rosetas pertencentes a clones. Nossos resultados mostram que o tamanho de corpo tem influência positiva significativa na produção de capítulos, mas explica apenas parte da variação nos dados. A produção de capítulos é maior em rosetas pertencentes a clones que em rosetas isoladas. Os clones geralmente apresentam uma roseta, ou um grupo de rosetas, que concentra a reprodução sexual. A clonalidade apresentou ligações significativas com a reprodução sexuada. Em ambientes sazonais a clonalidade pode representar uma importante forma de persistência das plantas já que pode permitir um melhor desempenho da reprodução sexuada em vista dos estresses ambientais. Os casos nos quais a clonalidade representa uma via de melhor dese...
Abstract:Fire occurrences are a common perturbation in Cerrado ecosystems, and may differently impact the local biodiversity. Arthropods are one of the taxa affected by fires, and among them, ants are known as good bioindicators. We aimed to evaluate the effect of anthropic fires on epigaeic and hypogaeic ant communities (species richness and composition) in Cerrado areas with different post-fire event recovery periods. We conducted the study in four Cerrado areas during two weeks of 2012 dry season: one unburned and three at different post-fire times (one month, one and two years). We sampled ants with pitfall traps in epigaeic and hypogaeic microhabitats. We collected 71 ant morpho-species from 25 genera. In the epigaeic microhabitat we sampled 56 morpho-species and 42 in the hypogaeic microhabitat. The area with the shortest recovery time presented lower epigaeic ant species richness (4.3 ± 2.00) in comparison to the other areas (8.1 ± 2.68 species on one year area; 10.3 ± 2.66 species on two years area; 10.4 ± 2.31 species on control area), but recovery time did not affect hypogaeic ant species richness. Regarding ant species composition, fire did not directly affect hypogaeic ant species, which remained the same even one month after fire event. However, two years were not enough to reestablish ant species composition in both microhabitats in relation to our control group samples. Our study is the first to assess anthropic fire effects upon epigaeic and hypogaeic ants communities; highlighting the importance of evaluating different microhabitats, to more accurately detect the effects of anthropic disturbances in biological communities. We concluded that ant communities are just partially affected by fire occurrences, and epigaeic assemblages are the most affected ones in comparison to hypogaeic ants. Furthermore the study provides knowledge to aid in the creation of vegetation management programs that allow Cerrado conservation. Rev. Biol. Trop. 64 (1): 95-104. Epub 2016 March 01.Key words: anthropic burning, brazilian savannah, post-fire recovery, conservation, bioindicators.The Brazillian Savanna (Cerrado) is a biodiversity hotspot presenting many endemic species (Myers, Mittermeier, Mittermeier, Fonseca, & Kent, 2000). Its vegetation can be characterized by sparse trees and continuous grassy fields and is influenced by seasonal rainy periods and various disturbances, with fire figuring as the major one (Huntley & Walker, 1982). Natural fires are common in the Savannas, chiefly caused by lightning reaching small patches in the rainy season (Ramos-Neto & Pivello, 2000), and have great importance in community dynamics maintenance in this biome (Townsend, Begon, & Harper, 2010). Fire can be considered one of the factors that allow the balance between tree and grass density, maintaining the main features of savanna vegetation (Higgins, Bond, & Trollope, 2000).Biological communities of savannas are widely adapted to fire action, having great resistance and resilience to this disturbance. This fact can be attrib...
Aquatic plants are able to alter their morphology in response to environmental condition variation, such as water level fluctuations. The aim of this study was to evaluate the effect of water level on Sagittaria montevidensis morphology through measures of vegetative structures formed in drought and flood periods. We hypothesised that the plant height and the biomass of S. montevidensis leaves will increase during flood periods, while the biomass and diameter of petioles, and the basal plant area will increase during dry periods. We sampled a total amount of 270 individuals in nine sediment banks per visit, totalling 1080 plants. In order to compare plant morphology between dry and flood periods, we measured the water level in each bank and took the following variables for each plant: diameter, height and diameter of the biggest petiole. In order to compare biomass allocation between dry and flood periods, we sampled a total amount of 90 individuals in nine sediment banks per visit, totalling 360 plants. Plants were dried and weighed in the laboratory. All measured morphologic traits, as well as the biomass of leaf blades and petioles, were higher during flood periods, indicating that water level highly influences the morphology of S. montevidensis individuals. Our results suggest that these morphological responses allow survival and maintenance of S. montevidensis populations under environmental stress. These results can be linked to the invasive potential of S. montevidensis and sheds light on basic management practices that may be applied in the future.Keywords: emergent macrophyte, drought, flood, water level, sediment banks.Plasticidade morfológica dependente do nível da água em Sagittaria montevidensis Cham. And Schl. (Alismataceae). ResumoAs plantas aquáticas são capazes de alterar a sua morfologia em resposta a variações nas condições ambientais, tais como mudanças no nível da água. Nosso objetivo foi avaliar o efeito do nível da água na morfologia de Sagittaria montevidensis através de medidas de estruturas vegetativas formadas em períodos de seca e de cheia. Nós hipotetizamos que a altura dos indivíduos e a biomassa das folhas de S. montevidensis aumentarão durante períodos de cheia, enquanto a biomassa e diâmetro dos pecíolos, além da área basal da planta, aumentarão durante períodos de seca. Nós amostramos um total de 270 indivíduos, distribuídos em nove bancos de sedimento, por visita, totalizando 1080 plantas. Para comparar a morfologia das plantas entre os períodos de cheia e seca nós medimos o nível de água em cada banco e tomamos as seguintes medidas para cada planta: diâmetro, altura e diâmetro do maior pecíolo. Para comparar a alocação de biomassa entre os períodos de cheia e seca nós amostramos um total de 90 indivíduos em nove bancos de sedimento por visita, totalizando 360 plantas. As plantas foram secas em estufa e pesadas em laboratório. As plantas foram maiores no período de cheia e também apresentaram maior número e biomassa de folhas, maior diâmetro e biomassa de pecíolos e mai...
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