Land use intensification can greatly reduce species richness and ecosystem functioning. However, species richness determines ecosystem functioning through the diversity and values of traits of species present. Here, we analyze changes in species richness and functional diversity (FD) at varying agricultural land use intensity levels. We test hypotheses of FD responses to land use intensification in plant, bird, and mammal communities using trait data compiled for 1600+ species. To isolate changes in FD from changes in species richness we compare the FD of communities to the null expectations of FD values. In over one-quarter of the bird and mammal communities impacted by agriculture, declines in FD were steeper than predicted by species number. In plant communities, changes in FD were indistinguishable from changes in species richness. Land use intensification can reduce the functional diversity of animal communities beyond changes in species richness alone, potentially imperiling provisioning of ecosystem services.

Resumo: Este trabalho apresenta um estudo sobre a diversidade da mandioca na região do médio Solimões, enfocando principalmente comunidades localizadas nas Reservas de Desenvolvimento Sustentável Mamirauá e Amanã, no Amazonas. O estudo associa dados quantitativos e etnográficos. A análise de dados de monitoramento de 13 comunidades de várzea e de terra firme revelou o seguinte padrão de diversidade de manivas (mandioca): riqueza total de 54 variedades, com distribuição ampla de poucas variedades e ocorrência localizada da maioria; riqueza média de dez variedades por comunidade; e coleções familiares com três variedades em média. Uma análise temporal das coleções familiares mostrou a natureza dinâmica da diversidade regional. Ao longo de cinco anos, praticamente todas as 55 famílias acompanhadas alteraram a composição de variedades, mas mudaram pouco o tamanho de suas coleções. Para discutir essa dinâmica da diversidade, realizamos pesquisa qualitativa em três comunidades. Buscamos entender as condições sociais e ambientais que os agricultores enfrentam, as preferências por certas manivas e os padrões de manejo das roças. Mostramos que a diversidade de manivas é resultado de uma prática de experimentação ativa e que a dinâmica das coleções é definida por um conjunto de fatores que inclui o contexto das práticas econômicas, as condições ambientais e a relação histórica da população regional com a mandioca.Palavras-chave: Agricultura familiar. Agrobiodiversidade. Mandioca. Maniva. Rio Solimões. Abstract:The paper presents a study on the manioc diversity in the Middle Solimões region, focusing largely on communities located in the Sustainable Development Reserves of Mamirauá and Amanã, state of Amazonas, Brazil. The study combines quantitative and ethnographic data. The analysis of survey data collected in 13 communities in the 'várzea' and in the 'terra firme' revealed the following pattern of manioc diversity: a total richness of 54 varieties, demonstrating a broad distribution of a small number of varieties and a local occurrence of the majority; an average richness of ten varieties per community; and an average of three varieties maintained per household. A temporal analysis of survey data collected at the household level illustrates the dynamic nature of this regional diversity. Over the course of five years, almost all the 55 accompanied families altered the composition of manioc varieties in their collections; however, the size of these collections showed little variation. To discuss the dynamics of diversity, we conducted qualitative research in three communities. This analysis sought to understand the social and environmental conditions with which farmers contend, patterns of manioc management, and the logic behind farmers' preferences for certain manioc varieties. The research demonstrates that maniva diversity is a result of active experimentation, and that collections of manivas maintained by farmers are dynamic and ever-changing. This dynamism is defined by a series of factors that include economic prac...

Melocactus violaceus is an endangered species due to habitat destruction and the overcollection of this species for ornamental use. The aim of this study was to test the effect of different temperatures on the germination of M. violaceus. Three treatments were conducted: a constant temperature of 25°C, a 20-35°C alternating temperature, both inside germination chamber, and an alternating temperature under room temperature (mean temperature ranged from 25-37°C). The fi nal seed germination rates at the alternating temperature treatments were not signifi cantly different (65% in the seed germinator and 62.5% at room condition). However, both treatments with alternating temperatures had signifi cantly higher germination rates compared to the treatment kept at the constant temperature (8%). Our study showed that alternating temperatures between 20 and 37°C provides satisfactory conditions to induce a high percentage of seed germination of M. violaceus, without the passage of seeds through the digestive tract of its natural disperser, the lizard Tropidurus torquatus. This condition contributes to effi ciently producing seedlings that can be reintroduced into conservation areas or used as ornamentals that may help reduce the overcollection of the remaining native populations.