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Abstract Clonal growth can be especially advantageous in spatially heterogeneous environments and some clonal plants are highly invasive or superdominant, especially in disturbed environments. However, their temporal dynamics in the absence of large disturbances are not well known. We assessed whether patches dominated by the native bracken fern Pteridium arachnoideum expanded or retracted in area over six years. We mapped the contour of eight patches occupied by P. arachnoideum in a savanna-forest transition every two years from 2009 to 2015. The area occupied by most patches was overall stable, indicating that forested patch boundaries may be unsuitable for an effective vegetative spread of P. arachnoideum. One patch fully retracted during the study period, possibly due to extensive herbivory by leafcutter ants. Thus, although clonal foraging may enable the spread of the species to more suitable sites from these patches, these results indicate that P. arachnoideum does not represent a threat to the biodiversity of savanna-riparian forest transitions in the absence of extensive disturbances, as the area of the largest patches remained stable or decreased during our study. These findings highlight that specific characteristics of the local disturbance regime may be key to the cost-effective management of some superdominant native species.

Recent studies have characterized the influence of agroecosystems on biodiversity. However, a set of components associated with the management of these areas is still neglected in landscape-level studies, especially in areas of recent agricultural intensification. The resources and conditions provided by agroecosystems to different species are highly variable in space and time, and failing to account for this variation may lead to misleading conclusions about the biodiversity status in these environments. In this perspective, we provide a conceptual overview to highlight why and which landscape components still need to be better explored to provide an adequate assessment of the agroecosystem effects on biodiversity. We used a Brazilian heterogeneous intensive-farming landscape as an example to outline the components that we believe are important for understanding biodiversity patterns in such landscapes. An in-depth description of agroecosystems can help us create better landscape-level management strategies and to design more effective green-way policies.

Several ecosystem processes and services provided by mangrove trees, such as the regulation of biogeochemical cycles, biological control, soil retention and protection against erosion, and especially CO2 assimilation and carbon storage are related to the photosynthetic process (Donato et al. 2011; Schaeffer-Novelli et al., 2016; Santos et al., 2017). Photosynthesis is directly related to chlorophyll present in the leaves, and assessment of chlorophyll concentrations may be used as an indicator of a plants’ physiological condition. Decreases in leaf chlorophyll concentrations occur in plants exposed to environmental stress, including stress caused by heavy metals (Chandra & Kang, 2016), nutrient deficiency (Kalaji et al., 2017), and petroleum pollution (Arellano et al., 2017), among others. Thus, estimates of chlorophyll concentrations may provide information on plant and ecosystem function (Heenkenda et al., 2015; Pastor-Guzman et al., 2015).

Conversion of natural to anthropogenic environments affects biodiversity, and the understanding of these impacts may be improved by assessing how different functional groups respond to such land conversion. We studied land conversion impacts on ant functional groups, as ants are ecologically important and respond well to various environmental changes. We hypothesized that conversion of natural to anthropogenic environments modifies the composition of functional groups, fostering generalist and opportunistic groups over specialist ones, with more responses of this type in tropical than in temperate regions. We recovered 412 papers from ISI Web of Science, of which we selected 17 studies, published between 1993 and 2018, that addressed our study’s question. We assessed whether each functional group responded positively or negatively to conversion of natural habitat into anthropogenic land uses and used Monte Carlo tests to assess significance. Ants were affected by natural habitat conversion into monoculture and polyculture and by the conversion of savannas and of tropical and subtropical forests. Land conversion affected six of the 13 functional groups assessed here. In the temperate zone, cryptic species, predators, subordinate Camponotini, cold-climate specialists and tropical-climate specialists were impaired, whereas hot-climate specialists were favored. In the tropics, land conversion negatively impacted fungus-growers and predators. In both climatic zones, several functional groups, mainly those with broad ecological niches, did not respond to land conversion. Our results corroborate that land conversion effects vary among ant functional groups and indicate that the ant fauna of temperate ecosystems may be more susceptible than that of tropical regions.

Abstract Deforestation can compromise ecological processes and biotic interactions, including the host–parasite relationship. While some parasites infect only one host, others require multiple hosts to complete their complex life cycles. In this context, different parasites may have different demands and traits and may have specific responses to habitat degradation. Here, we tested whether forest cover has different effects on different frogs' parasites, as chytrid (Batrachochytrium dendrobatidis; Bd) and helminths (Platyhelminthes and Nematoda). We collected data on two stream frog species (Crossodactylus caramaschii and Crossodactylus schmidti) from nine sites in the Brazilian Atlantic forest, with forest cover ranging from 20% to 99%. Bd presence and load increased with decreasing forest cover, but the opposite was observed for nematodes. Load of monoxenous and heteroxenous helminths increased with forest cover. We suggest that variations in potential host diversity, microclimate conditions, and host immune response may be responsible for the contrasting patterns found for micro‐(Bd) and macroparasites (helminths, except Platyhelminthes). Our work brings evidence of how habitat reduction can affect host–parasite relationships, including infection with the pathogen responsible for hundreds of global species extinctions.

Throughout the forest–tundra ecotone where trees and tall shrubs are becoming more abundant, knowledge of associations between shrubs and surrounding vegetation could inform predictions of their changing relationships. We assessed shrubs in 1 m × 1 m contiguous quadrats along two ∼450 m transects across tundra and ecotone landscapes near Churchill, Canada to determine patterns in relation to lakeshore edges, soil pH, microtopography, and other plant groups. We used wavelet analysis to assess patterns and generalized least squares for relationships with environmental variables. Shrubs were taller and more diverse at edges, particularly in tundra. The ecotone was more complex than tundra with greater variation in tall shrub and tree cover, shrub height, and microtopography. Shrub richness was positively correlated with microtopography but exhibited no relationship with pH. Bivariate relationships of shrubs with other plant groups varied for different scales. In tundra, shrub richness was negatively correlated with graminoids, forbs, and moss, but positively correlated with lichens within 1 m; opposite relationships were found at 4–60 m scales. Relationships in the ecotone were reversed and more complex at different scales. As trees encroach in the tundra, the spatial pattern of shrubs will become more complex at a variety of scales, likely with cascading effects on other plant types.

This article analyzes the phytotoxic activity of aqueous extracts from young and mature leaves of Serjania lethalis A. St.-Hil. on the germination and growth of Panicum maximum Jacq. seeds. We prepared aqueous extracts at concentrations of 2.5, 5.0, 7.5, and 10% from dry leaves and distilled water. Germination percentage, germination speed, and synchronicity were negatively affected by both extracts. The extracts exhibited phytotoxicity and reduced seedlings’ growth, and these effects depend on concentration. The different extract concentrations caused significant changes in the germination process and the growth of P. maximum seedlings, in some cases varying due to leaf maturation stage, but they did not differ from each other for most variables under analysis.

Este artigo analisa a atividade fitotóxica de extratos aquosos de folhas jovens e maduras de Serjania lethalis A. St. -Hil. sobre a germinação e o crescimento de sementes de Panicum maximum Jacq. Foram preparados extratos aquosos nas concentrações de 2,5, 5,0, 7,5 e 10% a partir de folhas secas e água destilada. A porcentagem de germinação, velocidade de germinação e sincronia foram afetadas negativamente pelos dois extratos. Os extratos exibiram fitotoxicidade e reduziram o crescimento de plântulas, e esses efeitos são dependentes da concentração. As diferentes concentrações dos extratos provocaram mudanças significativas no processo de germinação e crescimento de plântulas de P. maximum, em alguns casos variando devido ao estágio de maturação foliar, porém, não diferindo entre si para maioria das variáveis analisadas.

O objetivo deste trabalho foi realizar um estudo exploratório sobre as ações de educação ambiental desenvolvidas em unidades de conservação (UCs) brasileiras em relação a público, parcerias, linha pedagógica, objetivos, atividades, temas, avaliação e documentos de referência. Além disso, analisamos uma possível influência do Programa Nacional de Educação Ambiental (ProNEA) nessas práticas. Utilizamos dados de 56 UCs brasileiras coletados em questionário distribuído em 2007. Analisamos o total de UCs e dois grupos distintos: as que citaram e as que não citaram o ProNEA como referência. As ações educativas apresentam alguns princípios das novas tendências da educação ambiental e das políticas públicas elaboradas nos últimos anos no Brasil. Concluímos que embora uma política pública de larga escala, como o ProNEA, seja importante para orientar as mudanças desejadas, não é suficiente para que essas mudanças sejam incorporadas às práticas educativas.This paper presents the results of an exploratory study on actions in environmental education, developed in protected areas (PAs) of Brazil in relation to: the public; to partnership organizations; current pedagogical practice; intended objectives; activities realized; subject areas covered; assessments made and reference documents utilized. We also analyzed the influence on environmental education, of the National Environmental Education Program (ProNEA). We made use of data relating to 56 Brazilian PAs, collected from a questionnaire distributed in 2007. We analyzed all PAs together and also the PAs divided into two groups: PAs that cited and those that did not cite ProNEA as a reference document. The educational actions represent some of the principles emerging, as new trends in environmental education arise, and are reflected in public policy developed in Brazil over recent years. We conclude that although a large scale public policy, like ProNEA, is important in providing guidance for the desired changes, it is not sufficient to ensure that these changes be incorporated into educational practice.