Edge effects impact species richness and composition as a result of environmental changes caused by fragmentation. This study analyzed edge effects on a community of terrestrial ferns and lycophytes in an Araucaria forest in Brazil at sites subjected to differing edge conditions: (1) a site bordering a road running through the interior of a conservation unit, and (2) a site bordering an agricultural property. Twelve 10 × 10 m plots were selected at the edge and in the interior of each site, and accounted for a total of 48 plots. The edges had lost their characteristic floristic identity, suggesting that many species are sensitive to variations in environmental conditions. The edge effect had a negative impact on species richness as shown by the greater average numbers of fern and lycophyte species in forest interiors at both sites. The results showed that the forest fragments in contact with agricultural areas were subjected to more intense edge effects than the fragments bordering a road within a conservation unit.

Viticulture is an activity of economic importance in the state of Rio Grande do Sul, especially in Serra Gaúcha, which is the major grape-producing region. However, an increase in cultivated areas has been observed in other municipalities in the state. The aim of this study is to characterize mite diversity and community behavior on different varieties, recognizing which predatory species have potential to control phytophagous mites associated with Europan varieties in the Taquari Valley, Rio Grande do Sul state. The study was conducted in vineyards located in the municipalities of Marques de Souza: ‘BRS Vitória’ and cv ‘Itália’ “m”; Imigrante: cv ‘Itália’ “i”; Dois Lajeados: cv ‘Itália’ (c and f), ‘Tannat’ and ‘Chardonnay’; and Putinga: ‘Champanhe’ and ‘Moscato’. Samplings were carried out monthly in the period ranging from March 2017 to March 2018, during which twenty plants were randomly collected from each variety. Three leaves were clipped from each plant; one from the apical third, one from the median third, and one from the basal third, totaling 60 leaves per area. A total of 10,533 specimens were collected, belonging to 12 families, 38 genera, and 53 species, along with those belonging to the suborder Oribatida. The ‘Itália’ “c” variety had the highest abundance (2,012), followed by ‘Moscato’ (1,788) and ‘BRS Vitória’ (1,593). Phytoseiidae had the highest diversity among the mite families observed, with 20 species followed by Tetranychidae (8). The most abundant species were Polyphagotarsonemus latus (Banks) (3,420) and Euseius concordis (Chant) (565), present throughout the study period. ‘Chardonnay’ variety had the highest similarity (72.55%) among mite fauna compositions and the highest dissimilarity occurred between ‘BRS Vitória’ and ‘Champanhe’ varieties (95.48%). Environments evaluated in Dois Lajeados and Putinga were the most homogeneous concerning mite fauna diversity and abundance.

Riparian forests are essential to the maintenance of biodiversity and foster the development of ferns that are indicators of environmental quality. However, these forests have been degraded due mainly to high population density, pattern of urban settlement and agricultural expansion in rural areas. This study evaluated the environmental quality of 111 Estrutura comunitária de samambaias em mata ciliar …

Dicksonia sellowiana Hook. (Dicksoniaceae) is target of extractive exploitation and is threatened with extinction. We analyzed the population structure, the spatial distribution pattern of D. sellowiana and its relationship with environmental parameters within three fragments of Araucaria Forest in Rio Grande do Sul, Brazil. The fragments are of different sizes, namely, large (H1LF) with 246 ha, medium (H2MF) with 57 ha and small (H3SF) with 5.2 ha. Within each site, 1 ha was delimited, divided into 100 subplots (100 m2), of which 20 were selected with a draw. In each subplot, counting of the individuals, the registration of the caudice height and the coverage of leaves (SC) (m2), measurements of photosynthetically active radiation (PAR), canopy opening degree (CO), soil moisture (SM) and litter thickness (LT). The temperature (T) was measured inside each site. A total of 792 plants were sampled, of which 551 were concentrated in H1LF, 108 in H2MF and 133 in H3SF. An average of 1320 ha-1 individuals were estimated. Of the total including the three fragments, 96.9% of the individuals are in the first class of height (up to 0.8 m), indicating a great potential of population development. The spatial distribution pattern (AI) was aggregated in the three populations and the plants presented a heterogeneous total coverage, between 4.73 m2 (H2MF) and 2,223.47 m2 (H1LF). The highest values ​​of SC and SM were more related to the distribution of individuals in H1LF whereas the opposite was recorded in H2MF. The highest values ​​of PAR, LT and CO correlated with the distribution of D. sellowiana in H3SF. In addition to revealing that the H1LF population is among the most dense in southern Brazil, the results demonstrated a significant structural distinction between the interior populations of the fragments, in spite of them being located near to one another and being part of the same natural field matrix.

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Bioindicator organisms, such as edaphic invertebrates, are constantly used to assess disturbance, as they exhibit responses such as reduced community and changes in diversity, affecting the local ecosystem. The aim of this study was to compare the impacts of disturbance on the edaphic invertebrate community in both a pasture area and a native forest area, during summer and winter. Samplings were conducted for nine days using pitfalls. Bray-Curtis analyses, NMDS, ANOSIM, and SIMPER were applied. There was difference in richness and diversity between areas and seasons. Native forest pitfalls had higher similarity in abundance and diversity in both seasons than pasture pitfalls. Specimens belonging to 20 orders were collected; of those, Collembola, Hymenoptera, Diptera, and Hemiptera had the highest number of individuals. Seasonal influence on the organisms was evident. The impact on edaphic invertebrate community located in the pasture area showed that native forest has higher complexity and structural stability.

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