ABSTRACT The “campos” of the Pampa are unique Brazilian ecosystems, which provide key environmental services, including C storage. These grassy ecosystems have been rapidly converted to intensive land-uses, mainly intensive grain crops (soybeans) and Eucalyptus silviculture. These new land-uses could decrease soil C stocks, depending on soil management. This study aimed to assess soil organic carbon (SOC) changes after the conversion of native grasslands to cropland (soybeans/cover crops under no-tillage) and forestry (Eucalyptus). Eight representative sites in this biome were selected for soil sampling (Alegrete-ALE, Aceguá-ACE, Jari-JAR, Jaguarão-JAG, Pinheiro Machado-PIM, Lavras-LAV, Santo Antônio das Missões-SAM, São Gabriel-SAG). Soil sampling was conducted in dug pits (0.30 m wide × 0.30 m long × 0.40 m depth) spaced by 50 m at each site, to 0.30 m depth. Soil bulk density and SOC were obtained by samples obtained with volumetric rings. Soil organic C was analyzed by dry combustion. Soil C stocks were calculated per layer and cumulatively (0.00-0.20 and 0.00-0.30 m). Soil C content was higher under grasslands in soils from sites with finer, clayey texture (ACE, JAG), and lower in soils at sites with sandier topsoil. Land-use conversion to silviculture and cropland minimally affected SOC stocks. The same pattern was observed with soil N, because of the tight connection between C and N cycles. Soil bulk density was similar across sites and layers, but higher values were measured in sites with coarser texture. Mean SOC stock of the grassland sites was 62 ± 24.6 Mg ha-1, similar to 66 Mg ha-1 reported for grasslands soils of Rio Grande do Sul State, and higher than that reported by IPCC for this region (55 ± 4.4 Mg ha-1). Adopting these default values would lead to underestimation of baseline SOC stocks in the region. Land-use conversion to cropland did not affect SOC stocks significantly, probably because of the adoption of no-tillage system with winter cover crops. Soil C stocks were lower in Eucalyptus stands in the 0.00-0.30 m soil layer, which could be attributed to intensive soil management at planting and lower soil fertility in some sites. This lack of effect of conversion on soil C was attributed to the short time since conversion and adoption of soil conservation practices (no-tillage) in cropland. The study contributed to reduce existing soil data gaps in the region and supports Brazilian public initiatives like the ABC Program and National Greenhouse Gas Inventories. campos “campos services storage landuses, landuses land uses, uses soybeans (soybeans (SOC soybeans/cover soybeanscover notillage no tillage Eucalyptus. . (Eucalyptus) AlegreteALE, AlegreteALE Alegrete ALE, ALE (Alegrete-ALE AceguáACE, AceguáACE Aceguá ACE, ACE Aceguá-ACE JariJAR, JariJAR Jari JAR, JAR Jari-JAR JaguarãoJAG, JaguarãoJAG Jaguarão JAG, JAG Jaguarão-JAG MachadoPIM, MachadoPIM Machado PIM, PIM Machado-PIM LavrasLAV, LavrasLAV Lavras LAV, LAV Lavras-LAV MissõesSAM, MissõesSAM Missões SAM, SAM Missões-SAM GabrielSAG. GabrielSAG Gabriel SAG Gabriel-SAG) 030 0 30 (0.3 0.3 040 40 0.4 depth 5 site rings combustion 0.000.20 000020 0.00 0.20 00 20 (0.00-0.2 0.000.30 000030 0.00-0.3 m. m) finer (ACE , JAG) topsoil Landuse Land use cycles layers 6 246 24 24. ha1, ha1 ha 1, 1 ha- State 55 (5 44 4 4. ha1. ha-1) significantly (no-tillage Inventories (Eucalyptus Gabriel-SAG 03 3 (0. 0. 04 000 0.000.2 00002 0.0 020 0.2 2 (0.00-0. 0.000.3 00003 0.00-0. ( (0 0.000. 0000 02 (0.00-0 0.00-0 0.000 (0.00- 0.00- (0.00 (0.0

Resumo Objetivo A quantidade e a qualidade da água são essenciais para manutenção de muitos serviços ecossistêmicos, biodiversidade e bem-estar humano. No presente trabalho, utilizamos um experimento de campo para avaliar a percepção visual do público em relação à perda de qualidade da água associada à eutrofização e esverdeamento da água. Nós hipotetizamos que, com um aumento na eutrofização (ou seja, esverdeamento da água devido ao aumento da clorofila-a), as pessoas podem detectar uma perda de qualidade da água e ameaças aos serviços ecossistêmicos. Métodos Nós utilizamos uma área experimental composta por seis mesocosmos (caixas d'água de 500L) com gradiente de clorofila-a variando de águas claras (sem clorofila-a) até mesocosmos eutróficos (águas muito verdes). Um total de 100 pessoas visitaram a área experimental in-situ, e 83 pessoas visualizaram imagens dos mesocosmos. Resultados Nossos resultados indicaram que as pessoas foram capazes de detectar a perda de qualidade da água associada ao aumento das concentrações de clorofila-a, e reconheceram que estas eram menos adequadas para atividade recreativa e consumo. Além disso, essa percepção não variou por gênero, educação formal ou frequência de visitas aos ecossistemas aquáticos. Conclusões Os resultados evidenciam potencial da percepção visual do público como uma estratégia simples, rápida e de alerta precoce para programas de monitoramento da qualidade da água e também uma abordagem que fortalece o vínculo entre ciência e sociedade.

Abstract Aim The quantity and quality of water are essential to many ecosystem services, biodiversity and human well-being. In the present paper, we used a field experiment to evaluate the visual perception of the public regarding the loss of water quality associated with eutrophication and greening of water. We hypothesized that with an increase in eutrophication (i.e. greening of water due to increased Chlorophyll-a), people can detect a loss of water quality and threats to ecosystem services. Methods We used an experimental area composed of six mesocosms (500L water tanks) with a gradient of chlorophyll-a varying from clear water (without chlorophyll-a) up to eutrophic mesocosms (very green water). A total of 100 people visited the experimental area in-situ, and 83 people visualized pictures of the mesocosms. Results Our results indicated that people were able to detect the loss of water quality associated with increased concentrations of chlorophyll-a, and recognized that these were less suitable for recreational activity and consumption. Moreover, this perception did not vary by gender, formal education, or frequency of visits to aquatic ecosystems. Conclusions The results highlight the clear potential of visual public perception to be used as a simple, rapid, early-warning strategy for monitoring programs of water quality and also an approach that strengthens the link between science and society.

RESUMO Passiflora actinia Hook (nome popular: ‘maracujá-do-mato’) é uma espécie medicinal relevante devido às suas propriedades sedativas e ansiolíticas. Para uma exploração comercial da planta, no entanto, são necessários estudos de propagação, especialmente visando melhorar o enraizamento em estacas caulinares. O presente estudo foi desenvolvido para avaliar o efeito do extrato da alga marinha parda (Ascophyllum nodosum (L.) Le Jol.) aplicado na base de estacas caulinares de P. actinia. Foram avaliadas cinco concentrações do extrato diluído em água destilada: 0% (água destilada pura), 10%, 20%, 30% e 40%. O delineamento experimental foi o inteiramente casualizado com 4 repetições e 12 estacas por unidade amostral. As estacas foram avaliadas 45 dias após o plantio. Os dados foram analisados por meio de análise de regressão polinomial e coeficientes de correlação de Pearson foram calculados para todas as variáveis. Em média, verificou-se 51,27% de enraizamento. A porcentagem de enraizamento aumentou linearmente de acordo com as concentrações de extrato de alga marinha. Quando comparado ao tratamento controle, observou-se aumento de 10% no enraizamento quando as estacas foram tratadas com 40% de extrato de alga marinha. A resposta de retenção foliar às concentrações de A. nodosum também foi ajustada em modelo linear positivo. Um aumento de 15,6% na retenção foliar foi observado na concentração de 40% de extrato de alga quando comparado ao controle. Correlações positivas foram observadas para retenção de folhas e porcentagem de enraizamento e retenção de folhas e comprimento de raízes. A imersão das bases de estacas de P. actinia em extrato de A. nodosum em uma concentração de 40% pode promover efeitos positivos no enraizamento e facilitar a propagação desta espécie.

ABSTRACT Passiflora actinia Hook (common name: ‘maracujá do mato’) is an important medicinal species due to significant sedative and anxiolytic activities. In order to commercially exploit the plant, however, studies on propagation to improve rooting in stem cuttings are needed. The present study was designed to evaluate the effect of the brown seaweed (Ascophyllum nodosum (L.) Le Jol.) extract when applied on P. actinia stem cuttings bases. Five concentrations of the extract in distilled water were evaluated: 0% (pure distilled water), 10%, 20%, 30% and 40%. The experimental design was completely randomized with 4 repetitions and 12 cuttings per experimental unit. Cuttings were evaluated 45 days from planting. Data were analyzed through polynomial regression analysis and Pearson's correlation coefficients were calculated for all the variables. On average, 51.27% rooting was achieved. Rooting percentage increased linearly according to the brown seaweed extract concentrations. When compared to the control treatment, about 10% increase in rooting was observed at the treatment with 40% seaweed extract. Leaf retention response to A. nodosum increasing concentrations was also adjusted in a positive linear model. A 15.6% increase in leaf retention was observed at the 40% seaweed concentration when compared to the control. Positive correlations were observed for leaf retention and rooting percentage and leaf retention and roots length. The immersion of P. actinia stem cuttings bases in A. nodosum extract at a concentration of 40% promote positive effects on rooting and facilitate the species propagation.