Restauração florestal em áreas de antigas pastagens dominadas por Urochloa brizantha

In the present study it was evaluated the density of recruits in an area  previously occupied by Urochloa brizantha pasture undergoing forest restoration and in a Semideciduous Forest. Was evaluated the effect of the available light on the biomass of the exotic grass, and investigated associations of recruit density with soil variables and understory light availability. The seed rain in both areas was also evaluated. The biomass of U. brizantha was positively associated with available light and, a negative association was found between recruit density and available light when considering the two areas together. A negative associatio between recruit density and soil pH was found. The results suggest that the low soil fertility did not limited recruitment in the semideciduos forest. The results showed that high resource availability favors the competitivity of U. brizantha, impairing the forest restoration in area previously used as pastures. So, pratices that result in decreasing in light availability would favors the  forest restoration in areas previously used as pasture.No presente estudo foi avaliada a densidade de recrutas em uma área em restauração florestal previamente ocupada por pastagem de Urochloa brizantha e em uma Floresta Semidecidual. Foi avaliado o efeito da luz disponível sobre a biomassa da grama exótica e investigamos as associações da densidade de recrutamento com as variáveis do solo e a disponibilidade de luz no sub-bosque. A chuva de sementes em ambas as áreas também foi avaliada. A biomassa de U. brizantha foi associada positivamente com a luz disponível e, uma associação negativa foi encontrada entre a densidade de recrutamento e a luz disponível quando consideradas as duas áreas em conjunto. Foi encontrada uma associação negativa entre densidade de recrutamento e pH do solo. Os resultados sugerem que a baixa fertilidade do solo não limitou o recrutamento na Floresta Semidecidual. Os resultados mostraram que a alta disponibilidade de recursos favorece a competitividade da U. Brizantha com espécies nativas, dificultando a restauração florestal em áreas anteriormente utilizadas como pastagens. Assim, práticas que resultem na diminuição da disponibilidade de luz favoreceriam a restauração florestal em áreas nessas condições

A flórula rupestre do Pico de Itabirito, Minas Gerais, Brasil: lista das plantas vasculares

O presente trabalho apresenta um novo inventário de espécies de plantas vasculares de campos rupestres da Cadeia do Espinhaço. A área de estudos insere-se no Quadrilátero Ferrífero de Minas Gerais, na região do Pico de Itabirito, município de Itabirito, cujas coordenadas geográficas centrais são 20º 13′ 43″ S e 43º 51′ 39″ W. A área amostrada possui 1193 ha, com cotas superiores a 1300 m acima do nível do mar, cuja vegetação é constituída predominantemente por campos rupestres ferríferos e quartzíticos. Foram encontradas 722 espécies distribuídas em 100 famílias e 384 gêneros. As dez famílias com maior riqueza específica são Asteraceae (99 spp.), Orchidaceae (62 spp.), Melastomataceae (50 spp.), Leguminosae (36 spp.), Poaceae (30 spp.), Rubiaceae (26 spp.), Apocynaceae (23 spp.), Myrtaceae (22 spp.), Malpighiaceae (18 spp.), Cyperaceae (15 spp.), Eriocaulaceae (14 spp.) e Solanaceae (13 spp.). 47 espécies constam da revisão de 2012 das Listas das Espécies da Flora Ameaçadas de Extinção do Estado de Minas Gerais

Germinação de sementes de Senna macranthera, Senna multijuga e Stryphnodendron polyphyllum

With the aim of contributing to the knowledge about the wood legume Senna macranthera and Senna multijuga (Caesalpinaceae), and Stryphnodendron polyphyllum (Mimosaceae) seed germination, the seed imbibition curves were determined to identify the coat-imposed dormancy, and the procedures to overcome it with mechanical or chemical scarification. The coat impermeability was present in these three species and, the mechanical scarification was the most effective treatment to break the dormancy (germination percent up 80%). In S. macranthera, the chemical scarification with sulfuric acid by 12 minutes showed similar efficiency to the mechanical scarification. A variation in coat permeability between non-scarified seeds of S. polyphyllum was observed.Com o objetivo de contribuir para o conhecimento sobre a germinação de Senna macranthera e Senna multijuga (Caesalpinaceae) e Stryphnodendron polyphyllum (Mimosaceae), foram determinadas as curvas de embebição das sementes para identificar o grau de dormência imposta pelo tegumento e os procedimentos para superá-la (escarificação mecânica ou química). Nas três espécies verificou-se a presença de tegumento impermeável e a escarificação mecânica foi o tratamento mais eficiente para quebrar a dormência, com porcentagem de germinação superior à 80%. Em S. macranthera a escarificação química em ácido sulfúrico durante 12 minutos apresentou eficiência similar à escarificação mecânica. Observou-se também uma variação na permeabilidade do tegumento entre as sementes não-escarificadas de S. polyphyllum

Reproductive efficiency of nellore (Bos indicus) cows subject to both ftai and homeopathic supplementation

The aim of this work was to determine the effect of homeopathic supplementation on both ovarian dynamics and conception rate in Nellore cows subjected to fixed-time artificial insemination (FTAI). Cows (n = 150) were randomly distributed to the control (CG) and the homeopathy group (HG). The HG cows were supplemented with Pró-cio in the mineral salt for 60 days and both experimental groups were further subjected to FTAI. Cows were evaluated for ovarian dynamics (n = 16), progesterone (P4) concentration (n = 16), and conception rates (n = 150). Ovarian dynamics determined by ultrasonography and showed similar findings for CG and HG, respectively. Thus follicular diameter (8.7 ± 1.0 mm vs. 10.0 ± 0.8 mm), mean pre-ovulatory follicle volume (0.46 ± 0.15 mL vs. 0.61 ± 0.12 mL), and mean follicular growth (3.65 ± 1.41 mm vs. 4.60 ± 1.21 mm) did not differ between groups. Moreover, corpus luteum diameter was similar between groups (CG: 16.28 ± 0.7 mm vs. HG: 15.6 ± 0.8 mm; P > 0.05), although P4 levels did differ (CG: 2.55 ± 0.85 ng mL-1 vs. HG: 6.52 ± 1.19 ng mL-1; P 0.05). In conclusion, the homeopathic supplementation Pró-cio increases P4 concentrations but does improve the reproductive efficiency of Nellore cows subject to FTAI

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio