Resumo Objetivo Diversos fatores ecológicos afetam previsivelmente a diversidade beta - a dissimilaridade das comunidades entre locais ou através do tempo. Considerando o efeito da produtividade primária, existem divergências na literatura a respeito do tipo de relação que seria encontrada (positiva, negativa ou em formato de domo). Isto é relevante considerando a discussão do papel da produtividade primária na mudança das comunidades ecológicas através de processos determinísticos e estocásticos. O objetivo principal deste estudo foi elucidar a relação predominante encontrada entre a diversidade beta e a produtividade primária em artigos publicados, e quais fatores poderiam influenciar tal relação (escala, ambiente, organismo ou região biogeográfica). Métodos Realizamos uma análise cienciométrica seguindo o protocolo PRISMA para revisões sistemáticas. A busca dos artigos foi realizada através da base de dados ISI Web of Science®. Resultados O número de artigos abordando a relação entre a diversidade beta e a produtividade primária está crescendo ao longo do tempo mais do que o crescimento natural da ciência. Dos 465 artigos encontrados, somente 38 lidaram diretamente com a relação entre a diversidade beta e produtividade. Nestes 38 artigos, 76 relações foram encontradas, e a maioria destas foi positiva, em praticamente todos os fatores analisados. Somente relações negativas e estudos terrestres foram encontrados na região Afrotropical. Fica claro um viés para estudos com escalas grandes, ambientes terrestres, com vertebrados e nas regiões Neárticas e Paleárticas. Em ambientes aquáticos houve uma clara dominância dos estudos envolvendo invertebrados e micro-organismos/fungos. Conclusões O interesse em estudos envolvendo esta relação está aumentando. Relações positivas foram mais frequentemente encontradas nesta cienciometria. Lacunas no conhecimento foram evidenciadas, como a falta de estudos em escalas pequenas e médias, grupos além de plantas e vertebrados em ambientes terrestres, e estudos aquáticos nas regiões dos Afrotrópicos e Indo-Malaya.

Abstract Aim Several ecological factors are predicted to affect beta diversity - the dissimilarity of communities among localities or through time. Considering the effect of primary productivity, there is a divergence in the literature concerning if it is positive, negative or hump-shaped. This is relevant considering the discussion on the role of primary productivity on deterministic and stochastic processes shaping ecological communities. The main goal of this study was to review ecological literature to explore causes for variation in the predominant relationship between beta diversity and primary productivity. Methods We have performed a scientometric analysis following the PRISMA statement for systematic reviews and the articles search was made through the ISI Web of Science® database. Results The number of articles approaching the relationship between beta diversity and primary productivity is growing more than expected by the natural growth in published articles. From the 465 articles found, only 38 directly dealt with beta diversity-productivity relationship. From them, we extracted 76 relationships, most of them positive, in almost all factors analyzed. Even so, the proportion of negative studies was higher in aquatic environments. In the Afrotropic region, only negative relationships in terrestrial studies were found. There is a clear inclination towards studies regarding large spatial scales, terrestrial environments, with vertebrates and in the Neartic or Paleartic regions. In aquatic environments there was a clear dominance of studies using small-body organisms, contrasting with terrestrial studies that used more often vertebrates and plants. Conclusions There is an increasing interest in studies concerning this relationship. Positive relations can be explained by several ecological factors, and the more common negative relationships in aquatic environments can be explained by the fact that productivity can cause eutrophication. We also pointed out gaps in the knowledge, especially considering studies in small and medium spatial scales, groups beyond plants and vertebrates in terrestrial environments, and aquatic studies in Afrotropic and Indo – Malaya regions.

ABSTRACT Intensive growth of aquatic macrophytes interferes with water quality and ecosystem dynamics worldwide. Although mechanically removing macrophytes is the most commonly used method for their eradication, it can also cause undesirable disturbances in aquatic reservoir communities. We performed laboratory incubations of phytoplankton sampled before and after macrophytes were mechanically removed from the Piraquara II reservoir, South Brazil. We analyzed changes in growth and composition of the main phytoplankton groups with respect to nutrient shifting. Prior to removing the macrophytes, the phytoplankton community was dominated by low cell abundances of diatoms and flagellates. In contrast, growth rates of cyanobacteria (mainly Cylindrospermopsis raciborskii, Pseudanabaena sp., and Geitlerinema sp.) and of colonial chlorophytes were favored after macrophyte removal, while the abundances of diatoms and flagellates decreased. Our results suggest that removing macrophytes causes dramatic changes in phytoplankton composition and biomass and selects for toxigenic species of cyanobacteria. These changes were probably associated with the disturbance caused by removing the macrophytes, which immediately created new environmental conditions prone to species competition. These findings indicate that the use of mechanical techniques to manage macrophytes should be carefully considered, along with monitoring of harmful species and changes of limnological parameters.

ABSTRACT Latin America embodies countries of special interest for ecological studies, given that areas with great value for biodiversity are located within their territories. This highlights the importance of an evaluation of ecological research in the Latin America region. We assessed the scientific participation of Latin American researchers in ecological journals, patterns of international collaboration, and defined the main characteristics of the articles. Although Latin American publications have increased in fourteen years, they accounted up to 9% of publications in Ecology. Brazil leaded the scientific production in Latin America, followed by Argentina and Mexico. In general, Latin American articles represented a low percentage of most journals total publication, with particularly low expression in high impact-factor journals. A half of the Latin American publications had international collaboration. Articles with more than five authors and with international collaboration were the most cited. Descriptive studies, mainly based in old theories, are still majority, suggesting that Ecology is in a developing stage in Latin America.

ABSTRACT The toxigenic cyanobacterium Cylindrospermopsis raciborskii previously restricted to tropical latitudes, has been increasingly reported in temperate lakes in recent decades. The causes of its biogeographical expansion are under investigation, but efficient physiological adaptation to changes in temperature and light regimes are likely to be involved. The present study evaluated the morpho-physiological responses of a strain of C. raciborskii from southern Brazil to nine light intensities, from 9 to 250 µmol photons m-2 s-1. Blooms of this cyanobacterium are regularly recorded in the region. Morpho-physiological responses were measured based on growth rate and trichome length. Cylindrospermopsis raciborskii showed slow growth at low light intensities, 9 and 20 µmol photons m-2 s-1, and responded morphologically by increasing the length of trichomes. In turn, the strain displayed constant maximum growth rates at light intensities higher than 50 µmol photons m-2 s-1. These results support the hypothesis that C. raciborskii can survive under low light conditions and continue to produce viable trichomes. Moreover, the strain achieved high growth rates under a relatively wide range of light intensities, a physiological adaptation that can potentially be a competitive advantage in the phytoplankton community.

Um dos principais objetivos de monitorar as florações de cianobactérias em ambientes aquáticos é revelar a relação entre a abundância de cianobactérias e as variáveis ambientais. Esses estudos tipicamente correlacionam dados coletados simultaneamente. No entanto, as amostragens ocorrem esparsamente ao longo do tempo e não são capazes de revelar respostas de curto prazo na abundância de cianobactérias frente às mudanças ambientais. Neste estudo, testamos a hipótese de que relações mais fortes entre cianobactérias e variáveis ambientais no monitoramento de cianobactérias são encontradas quando a variabilidade temporal dos pontos de amostragem é incorporada nas análises estatísticas. Para isso, nós investigamos as relações entre cianobactérias e sete variáveis ambientais que foram amostradas duas vezes por ano, durante três anos, em 11 reservatórios, e dados de um monitoramento intensivo em um desses reservatórios. Relações fracas foram encontradas correlacionando dados coletados simultaneamente. De fato, o papel "altamente recorrente" do fósforo nas florações de cianobactérias não foi devidamente observado em todos os períodos de amostragem. Por outro lado, coeficientes de correlação mais fortes entre fósforo total e cianobactérias foram observados quando usamos a variabilidade dos pontos de amostragem. Nós também mostramos que as variáveis ambientais explicam melhor a densidade de cianobactérias quando um atraso é considerado. Nós concluímos que, no monitoramento de cianobactérias, a melhor abordagem para revelar os determinantes das florações de cianobactérias é considerar a variabilidade ambiental.

One of the main goals of monitoring cyanobacteria blooms in aquatic environments is to reveal the relationship between cyanobacterial abundance and environmental variables. Studies typically correlate data that were simultaneously sampled. However, samplings occur sparsely over time and may not reveal the short-term responses of cyanobacterial abundance to environmental changes. In this study, we tested the hypothesis that stronger cyanobacteria x environment relationships in monitoring are found when the temporal variability of sampling points is incorporated in the statistical analyses. To this end, we investigated relationships between cyanobacteria and seven environmental variables that were sampled twice yearly for three years across 11 reservoirs, and data from an intensive monitoring in one of these reservoirs. Poor correlations were obtained when correlating data simultaneously sampled. In fact, the 'highly recurrent' role of phosphorus in cyanobacteria blooms is not properly observed in all sampling periods. On the other hand, the strongest correlation values for the total phosphorus x cyanobacteria relationship were observed when we used the variation of sampling points. We have also shown that environment variables better explain cyanobacteria when a time lag is considered. We conclude that, in cyanobacteria monitoring, the best approach to reveal determinants of cyanobacteria blooms is to consider environmental variability.

Eunotia é um gênero de diatomáceas altamente diverso na região neotropical. A considerável variabilidade morfológica encontrada nas valvas de várias espécies deste gênero resultam em uma taxonomia muito confusa. Neste estudo, 12 táxons de Eunotia aderidos a Podostemumspp. foram investigados usando microscopia óptica (MO). Adicionalmente, microscopia eletrônica de varredura (MEV) foi utilizada para investigar a morfologia ultraestrutural de táxons mais abundantes. Amostras foram coletadas em quatro rios do Estado de Santa Catarina entre março de 2009 e julho de 2010. A diatomoflórula deste estado é pobremente conhecida em relação aos estados vizinhos no sul do país. Eunotia biseriatoides é um taxon com características intermediárias entre Eunotia e Perinotiae a circunscrição destes gêneros é discutida aqui.Eunotia odebrechtiana é muito similar morfologicamente a E. biseriatoides e a sinonimização é proposta, bem como a transferência da variedade E. odebrechtianavar. essequiboensis è espécie E. biseriatoides. A ultraestrutura de E. epithemioides é apresentada pela primeira vez em MEV, revelando a posição atípica da rimoportula dentro deste gênero. Uma nova variedade, E. pseudosudetica var.rotundata var. nov., foi proposta e comparada com a variedade típica. Com exceção de E. veneris, todos os outros 11 táxons apresentados aqui são novos registros para Santa Catarina.

Eunotia is a highly diverse diatom genus in the Neotropics. Considerable morphological variability of the valve showed in several species of the genus resulted in a quite confused taxonomy. Twelve Eunotiataxa attached to Podostemum spp. were investigated using the light microscopy (LM). Additionally, scanning electron microscopy (SEM) was used in order to investigate the fine morphology of most abundant taxa. Samples were collected from four rivers from the State of Santa Catarina between March 2009 and July 2010. The freshwater diatom flora from this south Brazilian state is poorly known in relation to its neighboring states. Eunotia biseriatoides has intermediate features betweenEunotia and Perinotia, and the circumscription of these genera is discussed here. Eunotia odebrechtiana is very similar in morphology to E. biseriatoides, and the synonymy is proposed, as well as the transfer of the variety E. odebrechtiana var.essequiboensis to the species E. biseriatoides. The fine structure of E. epithemioides is showed for the first time in SEM, revealing the unusual position of the rimoportula in this genus. A new variety, E. pseudosudetica var. rotundata var. nov., was proposed and compared with the typical one. Except by E. veneris, all other eleven taxa presented here are new records for the State of Santa Catarina, Brazil.