Management Alternatives for Urochloa decumbens Stapf. (Poaceae) Biological Invasion in \ud Brazilian Savannas

Urochloa decumbens is an African grass, highly competitive and aggressive that was introduced in Brazil for \ud cattle feeding and became one of the most serious invasive species in Brazilian savannas - Cerrado -, threatening \ud the native biodiversity. The objective of this study was to evaluate the efficiency of different management \ud techniques to control the invasive grass Urochloa decumbens. The study was conducted in two Cerrado reserves \ud in São Paulo State, Brazil, from July/2007 toJuly/2009. Six cerrado patches infested by U. decumbens were \ud selected, and a randomized block design was applied with the treatments: clipping once a year (CRI) and twice a \ud year (CRII), clipping and soil grubbing once a year (CRSI) and twice a year (CRSII), shading with nylon mesh \ud (SOM), and smothering by covering with canvas (ABF). After the treatments all biomass in the blocks was cut \ud and separated into categories (U. decumbens, native grasses, and dicotyledonous species), in July/2008 (first \ud year) and July/2009 (second year). The analyses followed permutation tests. In the first year the treatments ABF, \ud CRII and CRSII statistically differed from control, showing to be the most effective to manage U. decumbens, \ud however in the second year the treatments CRI and CRSI also showed to be effective. Therefore, in two years of \ud management U. decumbens can be controlled by smothering and grubbing once a year (with or without soil \ud digging) in areas where the invasion is not very extensive, as edges or small isolated patches inside the native \ud fragments

Disturbance as a factor in breaking dormancy and enhancing invasiveness of African grasses in a Neotropical Savanna

The Cerrado is threatened by wildfires and invasive species. We aimed to evaluate in laboratory conditions whether temperature fluctuation at the soil surface, resulting from the absence of vegetation due to fire, can affect the germination of Urochloa decumbens and U. brizantha, two invasive African grasses. Seeds of both species were submitted to simulations: 1) temperature during fire at 1cm belowground (F); 2) temperature fluctuation at 1cm belowground without vegetation cover for a month (TF); 3) (F) + (TF); 4) control at 25ºC. After treatments, seeds were put to germinate at 25ºC for 40 days. We had four replicates per treatment and three temporal replicates. We compared germination percentage and the mean germination time among treatments using ANOVA. The treatments TF and F+TF had the highest germination values for both species. The results showed that fire per se could not stimulate seed germination, however, they suggest that a disturbance that produces a pattern of temperature fluctuation is able to break dormancy and enhance seed germination and, consequently, increase the invasiveness of the study species. Vegetation gaps resulting from disturbance may become new sites of invasion. This information is important for making management decisions regarding the control of these species.We thank the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) and the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES/DGU 227/2010) for financial support. M.J.B. acknowledges the support from the programme FORESTERRA ERA-Net (Medwildfirelab, PCIN-2013-140-C04-03) and PROMETEO II (Desestres es/2014/038)

BioTIME: A database of biodiversity time series for the Anthropocene.

MotivationThe BioTIME database contains raw data on species identities and abundances in ecological assemblages through time. These data enable users to calculate temporal trends in biodiversity within and amongst assemblages using a broad range of metrics. BioTIME is being developed as a community-led open-source database of biodiversity time series. Our goal is to accelerate and facilitate quantitative analysis of temporal patterns of biodiversity in the Anthropocene.Main types of variables includedThe database contains 8,777,413 species abundance records, from assemblages consistently sampled for a minimum of 2 years, which need not necessarily be consecutive. In addition, the database contains metadata relating to sampling methodology and contextual information about each record.Spatial location and grainBioTIME is a global database of 547,161 unique sampling locations spanning the marine, freshwater and terrestrial realms. Grain size varies across datasets from 0.0000000158 km2 (158 cm2) to 100 km2 (1,000,000,000,000 cm2).Time period and grainBioTIME records span from 1874 to 2016. The minimal temporal grain across all datasets in BioTIME is a year.Major taxa and level of measurementBioTIME includes data from 44,440 species across the plant and animal kingdoms, ranging from plants, plankton and terrestrial invertebrates to small and large vertebrates.Software format.csv and .SQL

Management efficiency to control two invasive grasses in cerrado fragments, in São Paulo State

Nos cerrados brasileiros, várias gramíneas africanas foram introduzidas, tornando-se invasoras e ameaçando a biodiversidade nativa. É, portanto, imprescindível a elaboração de medidas para seu controle. O objetivo deste estudo foi avaliar a eficiência e o custo de diferentes métodos para o controle das gramíneas invasoras Urochloa decumbens e Melinis minutiflora, em unidades de conservação de proteção ao cerrado. O trabalho foi desenvolvido no Cerrado Péde- Gigante e na Estação Ecológica de Itirapina (SP, Brasil), onde foram selecionadas seis manchas com dominância de U. decumbens e seis com M. minutiflora. Em cada mancha, aplicou-se um bloco randômico com os tratamentos: corte raso, uma vez (CRI, nov/2007) e duas vezes (CRII, nov/2007 e mar/2008), corte e revolvimento do solo, uma vez (CRSI, nov/2007) e duas vezes (CRSII, nov/2007 e mar/2008), sombreamento (SOM), abafamento (ABF), estes aplicados em julho/2007, permanecendo cobertos respectivamente com tela de nylon e lona até mar/2008. Ao final do experimento (jul/2008), a biomassa das parcelas foi cortada e separada em categorias (graminóides nativas, U. decumbens, M. minutiflora, dicotiledôneas). As análises basearam-se em testes de permutação. Posteriormente, foram calculados os custos de cada tratamento com mão-de-obra, materiais, ferramentas, transporte e descarte para o manejo das áreas. Para U. decumbens, os tratamentos mais eficientes para reduzir sua biomassa foram ABF, CRII e CRSII, sendo o ABF economicamente viável apenas para manejo de pequenas infestações; para áreas maiores, os tratamentos de corte mostram uma melhor relação benefício/custo. Para M. minutiflora, ABF, CRII, CRSII e CRSI são eficientes em reduzir sua biomassa e o tratamento CRSI é o que possui maior relação benefício/custo, portanto, o mais viável para o controle de desta gramínea.Several African grasses introduced in the Brazilian savannas for cattle feeding became invasive, and now they severely threaten the native biodiversity. It is, therefore, fundamental to look for effective methods to control them. The objective of this study was to evaluate the efficiency and cost of different management techniques to control the invasive grasses Urochloa decumbens and Melinis minutiflora. The study was conducted in the Cerrado Pé-de-Gigante and Itirapina Ecological Station (SP, Brazil). Six plots dominated by U. decumbens and six by M. minutiflora were selected and a random block design was applied including the treatments: clipping once ( CRI, nov/2007) and twice (CRII, nov/2007 and mar/2008), clipping and soil digging once (CRSI, nov/2007) and twice (CRSII, nov/2007 and mar/2008), shading (SOM), mugging (ABF), being the last two applied in July/2007 and remained covered until mar/2008, respectively with nylon mesh and canvas. At the end of the experiment (jul/2008), all biomass in the blocks was cut and separated into categories (native grasses, U. decumbens, M. minutiflora and dicotyledons). The analyses were based on permutation tests. The cost of each treatment was calculated taking into account materials, tools, labor, transportation and discharge. The most effective treatments to reduce U. decumbens biomass were ABF, CRII and CRSII, being ABF economically viable only for small patches; the double-clipping treatments showed best benefit/cost value in large areas. The treatments ABF, CRII, CRSI and CRSII were effective in reducing M. minutiflora biomass, being CRSI the one which showed a best benefit/cost value; therefore, clipping and digging is the best way to control that grass

A relação entre fogo e uma gramínea invasora no Cerrado: o fogo pode ser utilizado como uma estratégia de controle?

Espécies invasoras e queimadas não-controladas são consideradas atualmente grandes ameaças à diversidade do Cerrado. Gramíneas invasoras podem alterar propriedades do material combustível, afetando o comportamento e regime do fogo em áreas invadidas. Para algumas invasoras, no entanto, o uso do fogo, dependendo de sua época e intensidade, pode auxiliar no manejo e controle dessas espécies. Desta forma, o objetivo desta tese foi avaliar a relação de retroalimentação entre uma gramínea invasora, Urochloa brizantha e o fogo no Cerrado. Para isso, foram realizados experimentos de queima controlada (2012-2015) em uma área de campo sujo na Reserva Natural Serra do Tombador (Goiás), a fim de verificar como U. brizantha afeta o comportamento do fogo, comparando queimadas em áreas invadidas e não invadidas e, em diferentes estações do ano. Além disso, foi avaliado como o fogo em diferentes frequências (anual, bienal e não queima) e épocas (meio e final da seca) afetam a invasora e as espécies nativas. Ainda, por meio de experimentos em laboratório, foram testados os efeitos indiretos (flutuação de temperatura) e diretos (choques térmicos) do fogo em sementes de U. brizantha e de outras invasoras (U. decumbens e Melinis minutiflora), assim como em sementes de gramíneas nativas, a fim de verificar como a germinação destas espécies é afetada pelo fogo. A presença de U. brizanha modifica o comportamento do fogo no meio da estação seca, aumentando o tamanho das chamas. No entanto, no final da estação seca, o fogo em áreas invadidas é mais intenso. Verificamos também que, independentemente da frequência ou época, o fogo reduz a biomassa morta de U. brizantha. Queimadas bienais no final da estação seca reduziram a cobertura de U. brizantha, mas não sua biomassa, enquanto que queimadas bienais no meio da seca tendem a facilitar a invasão em novas áreas. Com exceção dos gramínoides, que tiveram sua cobertura reduzida, as espécies nativas não foram afetadas pelo fogo. Sementes de U. brizantha e U. decumbens têm sua dormência quebrada com as flutuações de temperatura, independente do fogo, aumentando desta forma, sua porcentagem de germinação. Quando submetidas a choques térmicos (altas temperaturas), as sementes de Melinias minutiflora se mostraram resistentes, enquanto que as sementes de U. brizantha resistem e germinam com temperaturas menores de 200°C. Por outro lado, a germinação de U. decumbens não é afetada, mas a viabilidade das sementes diminui a partir de 100ºC. U. brizantha afeta o comportamento do fogo e se regenera rapidamente pós-fogo, o que indica que o fogo sozinho não poderia controlar esta espécie, mas poderia ser utilizado como controle de material combustível. Os resultados deste estudo poderão auxiliar na compreensão dos processos de invasão de U. brizantha e, sua relação com o fogo e assim, subsidiar ações de manejo em unidades de conservação.Biological invasions and wildfires are considered major threats to the Cerrado biodiversity. Invasive grasses can change fuel properties, affecting the behavior and the fire regime in invaded areas. However, for some invasive species, prescribed fires could be used to manage and control them. Thus, the aim of this thesis was to evaluate the feedback relationship between an invasive grass, Urochloa brizantha, and fire in the Cerrado. Experimental burns were perfomed (2012-2015) in a “campo sujo” area at the Tombador Natural Preserve (Goiás), to evaluate how U. brizantha affects fire behavior, comparing invaded and non-invaded areas and different seasons. We also sought to verify how fire in different frequencies (annual, biennial and control) and seasons (mid-dry and late-dry) affect the invasive and native species. Moreover, we tested, in the laboratory, indirect (temperature fluctuation) and direct (heat shocks) effects of fire on seeds of invasive (U. brizantha, U. decumbens and Melinis minutiflora) and native grass species to verify how germination of these species was affected by fire. The presence of U. brizantha changed fire behavior in the mid-dry season by increasing flame height and in the late-dry season by increasing fire intensity in invaded areas. We also observed that, regardless of the fire frequency or season, fire reduced the dead biomass of U. brizantha. Biennial fires in the late-dry season reduced the cover of U. brizantha, but not its biomass, while biennial fires in the middle of the late-dry season tended to facilitate invasion into new areas. Except for graminoids, which had its cover reduced, native species were not affected by fire events. Regarding the germination experiments, temperature fluctuation, independent of fire, broke dormancy of U. brizantha and U. decumbens seeds, increasing their germination. When submitted to heat shocks M. minutiflora seeds were resistant, while U. brizantha seeds were able to germinate and resist temperatures lower than 200°C. On the other hand, germination of U. decumbens was not affected by the heat shocks, but the viability of its seeds decreased with 100°C. Finally, the results found in this study have shown that U. Brizantha affects fire behavior and regenerates rapidly after fire, indicating that fire by itself could not be used to control this species. However, fire, in this case, could be used as fuel control to avoid wildfires. These results are valuable in understanding the invasion process of U. brizantha and its relationship with fire and thus aid in future management decisions and actions in protected areas.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Allelopathic evidence in Brachiaria decumbens and its potential to invade the Brazilian Cerrados

The aim of this study was to look for evidence of allelochemicals in B. decumbens, in parts of the plant from where they could easily be released to the environment. The germination inhibition of Phalaris canariensis, Lactuca sativa (standard species) and Melinis minutiflora, another invasive African grass, was tested using B. decumbens germinating seeds and aqueous leachates of the roots, green and senescent leaves, at 5, 10 and 20% w/v. Both the germinating seeds and the aqueous leachates of B. decumbens reduced the germination of the species tested; the effectiveness of the aqueous leachates increased according to concentration. Apparently, the competitive advantage of B. decumbens in the cerrados could be amplified via allelopathy.<br>Invasão biológica é uma das maiores causas atuais da perda de biodiversidade. Várias espécies que se tornam invasoras produzem substâncias fitotóxicas que aumentam sua capacidade competitiva; assim, a alelopatia é uma estratégia capaz de potencializar o sucesso de invasão. Brachiaria decumbens, uma gramínea africana, invadiu os cerrados brasileiros e representa, atualmente, uma séria ameaça à biota regional. Neste ensaio, verificamos a presença de aleloquímicos em partes de B. decumbens das quais poderiam ser facilmente liberados para o ambiente. Testamos a inibição da germinação de Phalaris canariensis, Lactuca sativa (espécies padrão) e Melinis minutiflora (outra gramínea africana invasora) usando sementes de B. decumbens e soluções aquosas lixiviadas de suas raízes, folhas verdes e folhas senescentes, a 5, 10 e 20% de peso do material por volume de água. Tanto as sementes como as soluções lixiviadas de decumbens reduziram a germinação das outras espécies; a eficiência dos lixiviados aumentou de acordo com a concentração da solução. Acreditamos que a grande vantagem competitiva de B. decumbens no cerrado possa ser amplificada pela alelopatia

Does season affect fire behaviour in the Cerrado?

Fire has played an important role in the plant dynamics and diversity of the Cerrado for millions of years. We evaluated fire behaviour in different fire seasons in areas of an open savanna, providing information for fire management plans. It has been hypothesised that early fires (May – end of the rainy season) will be less intense than those conducted in the middle and end of the dry season (July and October) owing to the amount of dead biomass accumulated. Therefore, we compared fire behaviour in early, mid- and late dry season, evaluating the main fire and environmental variables. Fire intensity was mainly influenced by the combination of dead fuel percentage and fuel load. Even though this combination was the best model to explain fire intensity variability, fire parameters (including fire intensity) did not differ between fire seasons. Flame height was best explained by dead fuel percentage + fuel moisture content, dead fuel percentage + fuel load and also by dead fuel percentage. Our study showed that, in areas with fire exclusion for 2 years, fire season did not influence fire parameters and fire behaviour and the main factors influencing fire intensity were the proportion of dead biomass and total fuel load.This study was supported by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq, project (476334/2011–0) and scholarship (141854/2012-0), Fundação de Amparo à pesquisa do Estado de São Paulo (FAPESP, project 2015/06743–0), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES/DGU (grant 10805/13–3, project 227/2010), Neotropical Grassland Conservancy and Fundação Grupo o Boticário de Proteção à Natureza (0153_2011_PR). MJB acknowledges the support from the Foresterra ERA-Net (Medwildfirelab project PCIN-2013–140-C04–03) European Commission. AF receives a grant from CNPq (306170/2015–9)