Araucaria Forest Research Articles

The Faxinal System in the State of Paraná: a Review

The Faxinal System is a traditional silvopastoral system located in fragments of Araucaria Forest in the state of Paraná (PR). In these areas, there is extensive animal husbandry between properties associated with the selective exploitation of forest resources. The Faxinal has been the subject of study by various branches of science, so new gaps and methods have emerged as research has progressed on the subject. To verify the evolution and new challenges of research on faxinals, a bibliometric review was carried out based on 125 articles collected by the Publish or Perish 8 program. The articles were organized according to the decade of publication (1980s; 1990s; 2000s; 2010s and early 2020s), the topic researched (economy, territory, cultural and environmental)and the geographical location of the faxinals. The number of articles on the Faxinal System has increased in recent decades, with a tendency for an even greater increase by 2029. Research has shown that, due to capitalist expansion,the strengthening of agribusiness and environmental problems, the Faxinal is failing to sustain itself in the traditional way and its long-term continuity is under threat. Considering this, we see the need for an integrated approach that promotes cooperation between the community, the private sector and government entities. In addition, initiatives aimed at research, education, training, technical support, and monitoring are fundamental to maintaining the Faxinal System, taking advantage of its sustainable potential.

Protection measures for the Araucaria Forest and their efficiency in the conservation of Araucaria angustifolia in southern Brazil

Protection measures for the Araucaria Forest and their efficiency in the conservation of Araucaria angustifolia in southern Brazil

Insect herbivory on ferns from a midland Atlantic Rainforest locality, southern Brazil: implications for interpreting fossil plant–insect interaction

ABSTRACT This work contains the results of fern–arthropod interactions from a midland Atlantic Rainforest locality and addresses the taphonomic, morphological and ecological implications of insect damage on ferns to interpret them on fossil plant assemblages. Six functional feeding groups – margin feeding, hole feeding, surface feeding, piercing and sucking, mining and galling – are present on the three fern species inhabiting the understory of an Araucaria Forest in the Atlantic Forest biome, southern Brazil. We recognised 19 damage types (DTs), including 14 arthropod-induced DTs, three of which are newly proposed herein. Five of the DTs found were first recorded on ferns. Of the DTs found, the proportion of guilds such as mining and galling shows a significant similarity with those of an upland locality. Products of arachnids and insect behaviour on ferns made up 25% of all fern–arthropod interactions in the midland locality, which included dead bodies and byproducts from processes of arthropod life cycle, which are unlikely to be preserved in the fossil record. This rate of arthropod products consists of significant evidence of interactions to unveil deep-time relationships between arthropods and plants. Lastly, leaf damage on living ferns is more frequent than those occurring in fossil plant assemblages.

Influence of large wood dynamics on flow and channel morphology in a forest stream

The riparian zone is a dynamic ecosystem formed by the interaction of aquatic and terrestrial components of rivers and serves as a source of the large wood (LW). We aimed to understand the LW dynamics and the LW influence on river morphology, sediment distribution, and flow velocity within three reaches of a low-order stream. The study was performed in a segment (770 m in length) of the Perdizes stream, located in Aparados da Serra National Park, southern Brazil. We framed the study by focusing three issues: i) the processes explaining the LW dynamics in the Araucaria Forest biome; ii) the effects of LW on the flow velocity along the study reaches, and iii) the presence of LW affecting the sediment longitudinal connectivity. The methodology consisted of: (i) collection of hydrological data (rainfall, discharge, and streamflow velocity), (ii) Perdizes stream characterization by topo-bathymetric survey and river-flow simulation with HEC-RAS 5.0.7 1D. and (iii) detailed field surveys of LW and bed sediments. The LW descriptions were performed at four moments (July 10, 2019; November 19, 2019; July 24, 2020; and December 18, 2020). Abundant LW, mainly from araucaria (Araucaria angustifolia (Bertol.) Kuntze), was observed before meanders. A notable reduction in LW volume and an increased proportion of araucaria, compared to deciduous trees, were observed within the channel. Mass balance analysis indicated fluctuations in riparian vegetation biomass, emphasizing the connectivity between vegetation and the river. Streamflow velocity decreased in LW presence, from occurrence to the margin. Bed sediment diameters were consistently smaller in cross-sections with LW presence. The accumulation of smaller sediments with LW indicated partial downstream sediment disconnectivity. HEC-RAS simulations confirmed increased LW deposition in lower velocity zones. This understanding of fluvial dynamics contributes to effective natural environment management, especially in the Araucaria Forest context.

Climate- and scale-dependent sex ratio in threatened Araucaria forests

Male and female dioecious trees often differ in their sensitivity to environmental stress, resulting in unbalanced sex ratios that can affect forest regeneration. Dioecious species are thus especially vulnerable to climate change, which can intensify their sexual bias. We investigated the sex ratio in endangered pehuén (Araucaria araucana) forests to determine whether there is an imbalance in ratio at different spatial scales, and if so, whether this is climate-dependent. To assess deviations in sex ratios on local and regional scales, we quantified the proportion of males along 37 transects within 11 patches in two populations. To assess the sex–climate relationship, we used WorldClim data; for the biogeographic scale, we added published sex ratio information from other populations. We found a bias towards males, both locally and regionally. On a local scale, this bias was related to heterogeneous temperature conditions, especially in patches with particularly wet or hot summers. On a biogeographic scale, this bias increased in warmer and humid conditions. The male bias we found implies a direct reduction in the effective size of these already threatened forests. Considering climate change projections for Patagonia, predicting an increase in temperatures and their anomalies, our results suggest that males would be less affected than females; this points to an intensification of the male bias, and thus to increased vulnerability of these already endangered pehuén forests. This study provides evidence of climate-dependent sex bias in threatened dioecious forests, and discusses its importance in the context of climate change.

Late Quaternary Araucaria forest and Campos (grasslands) vegetation dynamics inferred from a high-resolution pollen record from Lagoa Dourada in southern Brazil

Forest-grassland mosaics are ecosystems with sharp contrasts. Factors controlling their heterogeneity have interested researchers worldwide. To date, only few natural remains of these ecosystems exist, such as the Araucaria and Campos region in southern Brazil. Different paleoecological studies elucidate the vegetation and climate history of the region, documenting shifts between forests and grasslands since the Middle Holocene. However, uncertainty remains about whether system shifts were sudden or gradual and on the importance of driving factors and triggers such as climate, change and disturbance. We reconstruct the paleoecological history of the Araucaria forest-grassland mosaics in Paraná state in decadal to sub-decadal resolution during the Holocene. High resolution pollen analysis documents that in this region the expansion of woodlands occurred gradually while sedimentological analyses reveal stepwise shifts of the precipitation regime of the region. During the Early Holocene (10300-8300 cal yr BP), the landscape was characterized by grassland-dominated Campos vegetation, with sporadic occurrences of arboreal taxa. Araucaria angustifolia was present initially in small abundances. In the Mid-Holocene (8300-4000 cal BP), a transition to more humid conditions fostered the development of woodlands. The establishment of Araucaria angustifolia near the lake occurred around 7300 cal yr BP, together with a general expansion of woodlands. In the Late Holocene (4000-150 cal yr BP), Araucaria angustifolia became dominant within forest patches with a second stepwise expansion around 3300 cal yr BP. The onset of Euro-American land use during the last two centuries intensified erosion and altered species composition, reflected in sediment and pollen data. In addition, Lagoa Dourada documents vegetational changes that seem to coincide with the 8.2 ka event and the Little Ice Age.

Evaluating the impact of historical climate and early human groups in the Araucaria Forest of eastern South America

It has been hypothesized that the Araucaria Forest in southern Brazil underwent expansions in the past, driven either by human groups or by climate fluctuations of the Holocene and Pleistocene. Fossil pollen records of the Paraná pine Araucaria angustifolia, a dominant tree in that forest, provide some insights into when those may have occurred. Still, the timing of those expansions has never been estimated. To infer past range shifts and shed light on their main drivers, we employed next‐generation DNA sequencing (ddRADseq), machine learning, and a comprehensive database of fossil pollen records into a study of historical demographic inference and paleo‐distribution modeling of the Paraná pine. We found that A. angustifolia comprises two populations expanding at different times: one in the Mantiqueira mountain chain, the other in the southern Brazilian plateau. The southern population began to expand during the Last Glacial Period ~ 70 kya, long before human arrival in South America. Still, genetic analyses support that humans later impacted this population, resulting in lower genetic diversity, higher inbreeding, and high levels of gene flow over large distances with a weak pattern of isolation‐by‐distance. It is possible this resulted from human influence on seed dispersal and germination on the southern Brazilian plateau. The Mantiqueira population, in contrast, expanded only recently (~ 3 kya). This timing coincides with Holocene climatic changes and human settlements established further south, although, to date, there is little archeological evidence of human impact in the Mantiqueira. In addition, multitemporal species distribution models built from a combination of present‐day and pollen records infer a range expansion of the Araucaria Forest during glacial times until the cold humid HS1 event (~ 16 kya), when the forest was most widespread, with no evidence of glacial refugia. The combination of genomic and spatial analyses suggests that both human and climatic controls played a role in the dynamics of the Araucaria Forest.

Mineral changes in the rhizospheres of conifer plantations for a weathered subtropical soil

AbstractTree species can have great impacts on soil. Since the rhizosphere is more responsive to external inputs than the surrounding bulk soil, we investigated the rhizosphere effect of the exotic slash pine and the native araucaria in long‐term conifer monocultures in southern Brazil. Araucaria trees in a natural section of a nearby mixed araucaria forest were taken as the control. We assessed physical, chemical, and mineralogical properties of the underlying subtropical highly weathered soil. We did not find rhizosphere effects for most chemical and physical soil attributes, yet principal component analysis clearly distinguished the effects of the exotic and native conifers on rhizosphere properties by separating slash pine cluster from reforested and native araucaria clusters. Reductions in silt and sand contents under slash pine reforestation led to increases in clay and well‐crystallized iron oxides contents. The clay mineralogy comprised kaolinite, mica/illite, and hydroxy‐interlayered minerals, with kaolinite enrichment in the rhizospheres of both araucaria sites, mica/illite depletion in the rhizospheres of both araucaria and pine monocultures, and prevalence of well‐crystallized iron oxyhydroxides in the slash pine rhizosphere. This study demonstrates a tendency toward increasing soil weathering in the conifer monocultures, potential negative impacts of the faster growing slash pine reforestation on soil organic carbon, available P, and total K possibly by mica/illite depletion, while araucaria had lower impacts on soil properties. These results show long‐term potential loss of soil fertility and quality, which should be considered when monitoring soil changes in human modified ecosystems.

Sustainability Assessment of Araucaria Forest Remnants in Southern Brazil: Insights from Traditional Forest Inventory Surveys

Sustainability Assessment of Araucaria Forest Remnants in Southern Brazil: Insights from Traditional Forest Inventory Surveys

Traditional Yerba Mate Agroforestry Systems in Araucaria Forest in Southern Brazil Improve the Provisioning of Soil Ecosystem Services

Soils are a source of natural capital that provide and regulate a range of ecosystem services (ES) and play an important role in sustaining human welfare. Nonetheless, the quality and quantity of soil ecosystem services (SES) delivery over the long term depend on the use of sustainable land management practices. In the present study, we assessed seven SES using a set of soil quality indicators in four production systems based on yerba mate (Ilex paraguariensis A. St.-Hil) in the Araucaria Forest biome of Southern Brazil: two sites were under traditional agroecological agroforestry management, one was a silvopastoral system with dairy pasture, and the last one was a monoculture yerba mate production system. The SES measured were soil fertility, carbon sequestration, erosion control, nutrient cycling, plant provision, biodiversity, and health. Soil samples were collected at various depths and analysed for chemical, physical, and biological attributes. A principal component analysis on the dataset showed that the soil quality indicators that best represent the variance between the systems at the 0–10 cm layer were acidity, microbial activity (FDA), total nitrogen, (TN), structural stability index (SSI), cation exchange capacity (CEC), pH, sum of bases (SB), microbial quotient (qMic), density of earthworms (EwD), bulk density (BD), and carbon stocks (Cstock). Soil quality indicators ranging from 0 to 1 were used to graphically represent the set of SES. The indicator-based approach used to explain the differences among the four production systems was able to capture the soil functions and offered a good starting point for quantifying SES provision.

Co-Creating Strategies to Optimize Traditional Silvopastoral Systems through the Management of Native Trees in Caívas in Southern Brazil

The conservation of forest remnants in southern Brazil is closely related to historical land use, for example in systems such as caívas that occur within remnants of the Araucaria Forest and include livestock production and the extraction of yerba mate. Over the last decade, technologies adapted for these systems have been developed that promote a significant increase in animal productivity, without harming forest regeneration or the maintenance of the tree layer. However, the fertilization of pastures proposed in the technology has also promoted greater growth of native trees, with a consequent increase in shade levels. This, in turn, has affected the maintenance of pasture and yerba mate in the understory. Thus, this study sought to develop a methodology to adjust shade levels based on forest management that adheres to the limits permitted by current legislation. The objective was to evaluate the effect of tree management to maintain 50% shade levels on environmental indicators in a caíva that has been implementing pasture improvement technology since 2013. Native tree management occurred in 2020 and 2022 and the results were compared with data from the floristic survey of the area carried out in 2013. The results indicate that although the adoption of forest management to adjust shade levels reduced the density of individuals, it did not affect forest diversity, nor the basal area of the caíva tree layer. As such, it is possible to maintain pasture and yerba mate production in the area. Strategies like this are fundamental so that the forest landscape can continue to offer a source of production while also supporting environmental conservation.

Factors influencing early natural regeneration in areas under passive restoration in Araucaria Forest, southern Brazil

Factors influencing early natural regeneration in areas under passive restoration in Araucaria Forest, southern Brazil

Genetic diversity and fine-scale genetic structure of the conifer Podocarpus lambertii in a forest-grassland mosaic from Southern Brazil

Abstract Podocarpus lambertii (Podocarpaceae) is an endangered conifer, endemic to Brazil and occurring in continuous forest and forest-grassland landscapes from the Araucaria Forest. Aiming to support conservation efforts for P. lambertii populations and gain insights into the preservation of forest-grassland mosaics in southern Brazil, we assessed the spatial pattern, genetic diversity, and fine-scale genetic structure (FSGS) within a population situated in a forest-grassland mosaic. The study was conducted in a 9-ha plot in forest-grassland mosaic. All P. lambertii individuals with height ≥ 0.1 m were sampled and the population was stratified into four demographic categories (Seedling, Juvenile, Immature, and Reproductive). For each of these categories, we used 13 allozyme markers to evaluate the spatial pattern, genetic diversity and FSGS. All individuals occurred inside the forest-patches, presenting an aggregated pattern of distribution. Low genetic diversity was recorded for all categories and for the population ( H ⌢ E = 0.046 {\mathord{\buildrel{\lower3pt\hbox{$\scriptscriptstyle\frown$}}\over H} _E} = \,0.046 ), as well as a high number of rare alleles (20). Positive and significant FSGS was estimated only for the Juveniles ( θ ⌢ x y = 0.012 {\mathord{\buildrel{\lower3pt\hbox{$\scriptscriptstyle\frown$}}\over \theta } _{xy}} = \,0.012 ) up to maximum distance of 7.1 m, and the minimum viable area for the long-term conservation of Reproductive genetic diversity was approximately 68 ha. The set of our findings suggests that conservation actions need to enhance connectivity among forest-patches to prevent the loss of rare alleles due to genetic drift. Additionally, we highlight the significance of preserving forest-patches as repositories of species diversity and as crucial connectors between populations.

Aprimoramento de barras de cereais de aveia com adição de farinha de Araucaria angustifolia: semente, amêndoa ou casca

ABSTRACT: The feasibility of enhancing oat cereal bars, widely recognized for their health benefits, was investigated by replacing up to 5% oats with whole seed, almond, or steam-cooked pinhão husk flour. Pinhão contributes with resistant starch, antioxidant compounds, and minerals. The control oat bar (30.5% of the mixture), without pinhão flours but containing brown sugar (25.5%), raisins (15.0%), glucose (15.0%), coconut oil (3.0%), gelatin (0.5%), and water (10.0%), provides 75.53 kcal, with 15.66% carbohydrates (on a dry basis), 2.88% insoluble fiber, 0.70% soluble fiber, 1.82% protein, 0.62% lipids, and 0.32% minerals. Bars replacing up to 5% of oats with almond, husk, or whole seed flour showed statistically similar compositions, except for lipids, few minerals, phenolic compounds, and antioxidant activity. Concerning daily recommendations, a 22 g bar offers low energy (3.78%, Brasil, 1998) and proportionally high mineral content, including potassium (34.64%), zinc (81.58%), magnesium (108.55%), iron (421.18%), copper (192.98%), calcium (395.13%), and manganese (1,027.00%). Additionally, they exhibit a significant content of total phenolic compounds (8.66 mg GAE/g) and antioxidant capacity (24.43 mg Trolox/g). These innovative bars were well-received in sensory evaluations and demonstrated good commercial potential. Notably, a bar that replaced 5% oats with husk flour could be a viable option for microenterprises due to simplified technology, contributing to waste valorization and encouraging the preservation of the Araucaria Forest.

Leaf-Litter Anurans in An Agricultural Landscape in the araucaria Forest: A Case Study for Southern Brazil

Leaf-Litter Anurans in An Agricultural Landscape in the araucaria Forest: A Case Study for Southern Brazil

Restoration plantings in the Atlantic Forest use a small, biased, and homogeneous set of tree species

Investigating which species are planted in active restoration initiatives is useful for identifying underrepresented species and functional groups, which in turn can inform and improve the practice and policies of forest restoration. The Atlantic Forest is one of the global hotspots for biodiversity conservation and a region where many forest restoration initiatives have been carried out in recent decades. We conducted a taxonomic and functional analysis of a database with 1073 forest restoration plantings implemented from 2002 to 2018 in the Brazilian Atlantic Forest. We assessed how well restoration plantings represent the dispersal syndromes, successional groups, and the ratio of nitrogen-fixing, and threatened species, based on a comparison with 268 Atlantic Forest remnants. Comparisons were made for the entire biome as well as three subtypes: Atlantic Rainforest, Araucaria Forest and Seasonal Forest. We found 423 tree species planted in the restoration efforts, which represent less than 8 % of the Atlantic Forest tree flora. In comparison with the forest remnants, restoration plantings have a greater proportion of nitrogen-fixing tree species (17 % in plantings vs. 9 % in remnants) but underrepresent non-pioneer (67 % vs. 85 %), animal-dispersed (56 % vs. 74 %), and threatened species (18 species found in plantings vs. 83 in remnants). Our results indicate a bias towards N-fixing, non-animal-dispersed, and pioneer species in restoration plantings and towards using the same set of species across different regions of the Atlantic Forest. We recommend actions to increase the representation of the native tree flora in Atlantic Forest restoration plantings, especially concerning inclusion of animal-dispersed and threatened species and groups of species that are less likely to colonize restoration sites, such as large-seeded animal-dispersed species.

Allied species with Dicksonia sellowiana Hook. in a High Montane Araucaria Forest Remnant, in Southern Brazil

The Araucaria Forest in highlands is an environment characteristic of regions with altitudes greater than 1200 above sea level, in southern Brazil. The species that occur in this place are adapted to conditions of low temperatures and high humidity, where the presence of Dicksonia sellowiana Hook., a tree-sized pteridophyte with expressive importance value in many remnants. This research aimed to identify the associations of this species in a remnant of Araucaria Forest in the mountain region of Santa Catarina. The site was inventoried with permanent plots of fixed area of 200 m², which were systematically and contiguously distributed in 3 transects following the slope gradient of the terrain (1411 to 1940 m). The surveys evaluated the scientific name, geographic coordinates and DBH, with an inclusion limit of 5 cm for each individual. Subsequently, 14 individuals of D. sellowiana were randomly selected and used as a reference to the center of the sampling units of Prodan method, than the six closest trees were measured, identified and measured the distance from the center of the unit sampling to the sixth tree (R6) to determine its area. As the measurements of the permanent plots contain the geographic coordinates of all trees, the selection of Prodan sampling units and the collection of data (R6, N.ha-1, G.ha-1) were performed using ArcGis Software. The average basal area value was 69.5 m².ha-1 and the average density was 1628 ind.ha-1, values compatible with those obtained in the permanent plots (69.4 m².ha-1 and 1630 ind.ha-1 respectively), obtaining sample sufficiency by the collector curve. Dicksonia sellowiana showed association with 14 species, being inserted in characteristic environments with less sun exposure, slopes and presence of watercourses, generating an environment with low floristic diversity, however, with a high degree of endemism in the Atlantic Forest.

Colonization and transformation of landscapes in the Araucaria Forest in the twentieth century

RESUMO Este artigo interpreta parte dos processos migratórios e de colonização ocorridos no Sul do Brasil e em Misiones, na Argentina, na área da floresta com araucárias, impulsionados por companhias colonizadoras privadas e políticas públicas de repovoamento do século XX. Utiliza estudos de engenheiros agrônomos e de outros estudiosos argentinos que identificaram a área de distribuição da Araucaria angustifolia (Bertol.) Kuntze em Misiones. Discute, assim, o processo de exploração da araucária e de outras espécies arbóreas nativas no desenvolvimento econômico de Misiones e as correspondentes redução e fragmentação dos ecossistemas florestais, a construção de paisagens e a perda de biodiversidade.

Toxicological and chemoprevention studies of Brazilian brown propolis from Araucaria sp

ABSTRACT Brazilian brown propolis (BBP) is a natural product derived predominantly from the south region of Brazil, where Araucaria forests are dominant. Despite its potential as a source of bioactive compounds with leishmanicidal, anti-inflammatory, nociceptive, and antimicrobial properties, BBP has not been comprehensively studied compared to green propolis. Therefore, this study aimed to determine the safety and chemopreventive potential of BBP. The cytotoxicity attributed to BBP was assessed using two different assays, while the Salmonella/microsome assay was employed to evaluate mutagenicity. The acute toxicity attributed to BBP was determined using a zebrafish model, while the chemopreventive potential was investigated utilizing Chinese hamster lung (V79) cell lines. Data demonstrated that BBP exerted cytotoxic effects at concentrations greater than or equal to 10 µg/ml and did not exhibit mutagenicity in Salmonella typhimurium strains TA98 and TA100. However, at the highest concentration tested (4000 µg/plate), BBP induced a significant increase in revertant colonies in S. typhimurium TA102 strain. The LC50 equivalent to 8.83 mg/L was obtained in the acute toxicity evaluation in zebrafish. BBP also showed antigenotoxic effect by significantly reducing chromosomal damage induced by the mutagen doxorubicin in V79 cell cultures at a concentration of 2.5 μg/ml. Compared to Brazilian green and red propolis, BBP exhibited greater toxicity. On the other hand, at lower concentrations, BBP displayed chemopreventive potential, which may be associated with the antioxidant capacity of the extract. These findings contribute to a better understanding of the biological properties and potential applications of BBP in treating various diseases.

Natural Regeneration and Conservation Status of the Tree Community of Forest Remnants in Urban Parks in Southern Brazil

Purpose: The study characterised the dynamics of the natural regeneration process of urban remnants in four Curitiba (PR, Brazil) urban parks, aiming to contribute to the green infrastructure management process in Araucaria Forest areas. Theoretical framework: Urban forests offer significant socio-environmental benefits, being relevant for maintaining ecosystem services for cities and their inhabitants. Studying the regeneration of forest remnants in urban environments is essential for analysing their conservation status. Method/design/approach: The floristic diversity, structure, and population dynamics of the shrub-regenerating component of urban forest remnants were studied through the analysis of phytosociological parameters and the similarity between the shrub-regenerating, and arboreal components was verified. Results and conclusion: Significant dissimilarity was found between the study areas' regenerating shrub and tree components. The forest remnant of the Municipal Zoo, located in a locality with greater integration of different green areas, showed the best conservation status and a more advanced process of forest succession. Research implications: The analysis of the natural regeneration of urban remnants serves as an essential diagnosis regarding their conservation status and the capacity of species to perpetuate in the place, in addition to inferring about the connectivity with other urban remnants, being of great importance for the planning of actions aimed at the management of urban forests. Originality value: Analyzing natural regeneration generates information on forest remnants' conservation status and resilience, which is essential for planning actions for urban forest management.