Natural Forest Areas Research Articles

Survey of the Culicide community (Diptera: Culicidae) in the Caatinga Biome, Bom Jesus City, Piauí, Brazil

Mosquitoes are insects of great medical importance, acting as vectors of arboviruses and other pathogens that could be transmitted to humans. With the climate change many species of mosquitoes have adapted to survive in these altered conditions. The goal of this study was to describe the community of Culicidae in three gradients of environment within the Caatinga biome in the Bom Jesus municipality, Brazil. The environmental gradients included ​​native forest, rural and urban areas. Mosquitoes were collected and the following variables were analyzed: total and relative species abundance, total and relative species frequency, diversity, domain, the correlation among meteorological data, genus and the similarity between areas. The captures were made monthly for three consecutive days for a one-year period. Passive capture was performed using CDC traps placed a minimum distance of 50 meters apart in each sampling site. The mosquitoes collected were identified as: Aedeomyia spp., Aedes spp., Anopheles spp., Culex spp., Coquillettidia spp., Psorophora spp. and Uranotaenia spp. The genres Aedes, Anopheles, Culex, Coquillettidia and Psorophora were present year-round in at least one of the areas. The most abundant genres were the Anopheles and Culex, respectively. The native forest contained the highest diversity. However, the highest abundance of individuals was found in the rural areas, suggesting species adaptation to anthropized environments. Overall, the high abundance of the genus Anopheles and Culex is a public health concern as these genres are known to be involved in the transmission of malaria, human filariasis, and arboviruses.

Arbuscular Mycorrhizal Fungal Assemblages in Conservation Unit of Atlantic Forest Areas Under Native Vegetation and Natural Regeneration.

Arbuscular mycorrhizal fungi (AMF) play an important role in the dynamic of plant community in the south American Atlantic Rainforest biome. Even in protected areas, this biome is under several anthropic impacts, which can cause shifts in the soil microbiota, including AMF. This study aimed to determine the structure and composition of AMF community in areas of native Atlantic Forest and in natural regeneration and to identify which abiotic factors are influencing this community in these areas. Soil samples were collected at Monte Pascoal National and Historical Park, in Southern Bahia, in native and natural regeneration areas of Atlantic Forest in two seasons (rainy and dry). Greater number of glomerospores and richness and diversity of AMF were found in the area under regeneration, with differences between seasons being observed only for the number of glomerospores. Seventy-seven species of AMF were recorded, considering all areas and seasons, with Acaulospora and Glomus being the most representative genera. Greater abundance of species of the genera Acaulospora, Claroideoglomus, and Septoglomus was found in the regeneration area. The AMF community differed between the study areas, but not between seasons, with soil attributes (pH, K, Al, Mg, m, and clay) structuring factors for this difference in the AMF community. Atlantic Forest areas in natural regeneration and the soil edaphic factors provide changes in the structure and composition of the AMF community, increasing the richness and diversity of these fungi in conservation units.

Stock and indices of carbon management under different soil use systems

The aim of this study was to evaluate the stock of total organic carbon (TOC) and to perform the physical-granulometric fractionation of soil organic matter (SOM) in different management systems (MS). Three MS and one reference area of Native Forest (NF) were studied, and the three systems were sugarcane (SC), permanent pasture (PP) and no-tillage system (NTS). Soil samples were collected in the 0–0.05, 0.05–0.10, 0.10–0.20-m layers. Soil density (Sd), TOC, stratification index (SI), carbon stock (StockC), variation in StockC (∆StockC), carbon content of particulate organic matter (C-POM) and mineral organic matter (C-MOM), carbon stock index (CSI), lability (L), lability index (LI), and carbon management index (CMI) were determined. The MS presented higher Sd than the NF area. The NF area had higher TOC contents in the first layers, reaching 25.40 g kg-1 in the 0–0.05-m layer, with the PP area having higher values than the NF in the 0.10–0.20-m layer. The NF area showed the highest levels of C-POM (15.25 g kg-1) and C-MOM (10.15 g kg-1) in the first layer. In the 0.10–0.20-m layer, the PP and NTS systems were superior to the others. Regarding the C-MOM content, SC and PP showed higher levels in the 0.10–0.20-m layer. The highest CMI values were observed in the NTS and PP areas in the 0.10–0.20-m layer. The MS increased the Sd and reduced the TOC levels. The different MS modified the POM fraction, and the MOM fraction was most impacted by the SC area. The lability of the SOM was altered by the MS in the most superficial layers.

Insecta and Collembola as bioindicators of ecological restoration in the Ombrophilous Dense Forest in Southern Brazil

Abstract The objective of this study was to evaluate the capacity as bioindicators of litter arthropodofauna in pasture restoration in the Atlantic Forest Biome. Areas of native forest under natural regeneration, and pastures treated with different ecological restoration techniques were evaluated, with pitfall traps. The sampling period was from April/2017 to October/2018, bimonthly. Families Ptiliidae, Staphylinidae, and Leiodidae, species Pheidole cf. sarcina (Formicidae) and Mastigoceras sp. 1 and Szeptyckitheca sp. 1 (Collembola) were indicators of well-conserved areas, whereas families Cicadellidae and Delphacidae, Formicidae species Wasmannia auropunctata (Roger, 1863) and Camponotus melanoticus Emery, 1894 were indicators of degraded areas. From the springtail community, species richness is a metric that can be used as a bioindicator. It was observed that all taxonomic identification levels allowed for the differentiation of the environmental conditions of the sampling areas, with less specific identification levels, such as family, possibly indicating changes in areas under the restoration process.

Assessment of the impact of the urbanized territory of Yekaterinburg city on the formation of undergrowth in the forest park zone

The parameters of the undergrowth in the forbs and berry groups of pine forest types in 9 parks in Yekaterinburg and areas of natural forest have been investigated. Data on the species composition, density, and distribution by groups of heights of plants that make up the undergrowth collected. It has been established that the transformation of the undergrowth by an urbanized environment neutralizes the influence of the growing conditions of the considered forest types on it. In the forest-park zone, an increase in the density of the undergrowth is observed in comparison with the natural forest. The specificity of the forest park undergrowth is the floristic contamination with adventive species, the number of which is close to 50% of the total number of undergrowth species. The coefficient of floristic similarity of the undergrowth, according to the Sorensen coefficient between forest parks and a site of natural forest, was 0.26-0.46. In quantitative terms, the self-seeding of adventive species in the undergrowth is less than that of native plants. The invasive activity of ash-leaved maple in city parks and its dynamics over a 10-year period are considered, using the example of one of the parks.

Long-term effects of tillage systems on liming efficiency, soil chemical properties and wheat yield in Southern Brazil

Context Sustainable management of the soil is one of the pillars of conservation agriculture (CA). Aims The objective of this study was to evaluate the long-term effects of soil management systems (SMS) on liming efficiency, soil chemical properties and wheat yield. Methods This study was part of a long-term experiment established in 1986 in Passo Fundo, Rio Grande do Sul, Brazil, but using data from 2008 to 2015 to explore the effects of agricultural lime applied in 2008. The experiment was laid out in a split-plot design where the main plot (SMS) were arranged in randomised blocks and the cropping systems (sub-plot treatments) were randomised within the main plots. This study assessed the effects of the SMS; i.e. two CA systems [no-tillage (NT) and reduced tillage] and two conventional tillage (CT) systems (disk ploughing + disk harrowing annually, and mouldboard ploughing + disk harrowing annually). Key results The NT system was the most sustainable due to improvements in soil organic carbon concentration. After liming, CT systems were more effective than CA systems in decreasing Al3+ toxicity and increasing soil pH and Ca2+ and Mg2+ concentrations at deeper soil layers. The NT system had a considerable advantage over other SMS, due to a greater average wheat yield (18%). Conclusions The SMS evaluated in this study modified chemical properties when compared with the native forest area. The NT system was the least detrimental to soil organic carbon, an important indicator of soil quality. Implications The NT system provided greater average wheat yield (18%), and thus was the most viable SMS for subtropical spring wheat production.

Edaphic Invertebrates as Indicators of Soil Integrity Quality

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.

Remote Sensing Based Analysis of Land Use/Cover Change Impact in the Interface Between Magamba Nature Reserve and Surrounding Villages in Lushoto District, Tanzania

Several studies in Tanzania focus on land use/cover change (LULC) at coarse scale and without considering the adjoining (interface) landscapes i.e. landscape link community farming systems and forest/nature reserves. In the Eastern Arc Mountains in particular, LULC change that confront the interface between surrounding community landscape and nature reserves and the associated livelihood are not well understood. A study was conducted in the Usambara Mountains, Tanzania to explore the potential impacts of LULC on the interface between Magamba Nature Reserve (MNR) and the landscape of the surrounding community villages. Remote sensing and GIS techniques were used to quantify and analyse the trend in LULC changes over the past 31 years whereby satellite images of 1984, 1995 and 2015 were used. Household surveys, field observations and focus group discussions to 72 households in 3 villages surrounding the nature reserve were employed to capture data on human activities in the interface. The change detection was done by post classification approach using image interpreter| GIS analysis| matrix tool in QGIS software and processed in an intensity analysis program (Pontius matrix excel sheet). Descriptive statistical analysis (frequency counts and percentages) was used to explain human activities of communities adjacent to the MNR. Qualitative data were analysed using content and structural functional analytical techniques. Over the period (1984-2015) natural forest covering the major part of reserve decreased by 14%. The declining trend for forests in the study area is largely attributed to the increasing agricultural activities, settlements and infrastructure. Results revealed further that natural forest area and wetlands had active intensity of gain over the period 1984-1995 while in the 1995-2015 period had active intensity of loss. The most common human activities related to the spatial and temporal dynamics of LULC change in the MNR interface were firewood collection for household use, collection of medicinal plants, illegal timber harvesting, animal grazing, cutting trees for building poles and charcoal burning. Firewood collection is the most important human activity associated with forest degradation in MNR interface. Collection of medicinal plants from the reserve is associated with forest destructive process in the sense that it involves uprooting plants, root cutting, and tree ring debarking. The study recommends that policy makers as well as nongovernmental organizations should identify and establish potential low cost alternative sources of energy for usage by rural domestic household. Further research to predict and map spatial and temporal LULC dynamics at landscape scale should consider future scenarios on the evolution of forest-rural landscape interfaces and their impact on the provisioning of ecosystem services (ESS).

An Automated Approach for Extracting Forest Inventory Data from Individual Trees Using a Handheld Mobile Laser Scanner

Many dendrometric parameters have been estimated by light detection and ranging (LiDAR) technology over the last two decades. Handheld mobile laser scanning (HMLS), in particular, has come into prominence as a cost-effective data collection method for forest inventories. However, most pilot studies were performed in domesticated landscapes, where the environmental settings were far from those presented by (near)natural forest ecosystems. Besides, these studies consisted of numerous data processing steps, which were challenging when employed by manual means. Here we present an automated approach for deriving key inventory data using the HMLS method in natural forest areas. To this end, many algorithms (e.g., cylinder/circle/ellipse fitting) and machine learning models (e.g., random forest classifier) were used in the data processing stage for estimation of the tree diameter at breast height (DBH) and the number of trees. The estimates were then compared against the reference data obtained by field measurements from six forest sample plots. The results showed that correlations between the estimated and reference DBHs were very strong at the plot level (r=0.83–0.99, p<0.05). The average RMSE for tree DBHs was 1.8 cm at the forest landscape level. As for tree detection, 92.5% of 292 trunks were correctly classified on point cloud data. In general, estimation accuracy was sufficient for operational forest inventory needs. However, they could markedly decrease in »hard plots« located at rocky terrains with dense undergrowth and irregular trunks. We concluded that area-based forest inventories might hugely benefit from the HMLS method, particularly in »easy plots«. By improving the algorithmic performances, the accuracy levels can be further increased by future research.

Soil chemical properties in vineyard areas in the southern region of the state of Santa Catarina, Brazil

Abstract The objective of this work was to evaluate changes in the soil chemical properties and the critical environmental limit for phosphorus (CEL-P) in vineyards, in the southern region of the state of Santa Catarina, Brazil. Soil samples were collected at 0-5, 5-10, 10-20, and 20-40 cm soil depths, in vineyards aged 22, 36, and 60 years, and in the area of an adjacent native forest. The following parameters were analyzed: granulometry, pH in water, and exchangeable Al levels, to obtain potential acidity and Al saturation; and available levels of P and K, and exchangeable levels of Ca and Mg, to determine base saturation, cation exchange capacity; and soil organic matter (SOM). In comparison with the forest soil, the vineyard soils showed increased pH values, P, K, Ca, Mg, Cu, Zn, and SOM levels, and base saturation, as well reduced Al saturation, with more accentuated effects in areas with the longest cultivation time. The vineyards show changes in soil chemical properties with time and P levels above the CEL-P, at least in one of the soil layers.

Edaphic fauna affects soybean productivity under no-till system

This study aimed to evaluate the relationship of edaphic fauna under a no-tillage system with different levels of soybean productivity [High (NTH), Medium (NTM) and Low (NTL)] in the west of Santa Catarina (Brazil), identifying which chemical and physical variables most affect them, and the best indicators that can be used. Native forest (NF) areas were used as a reference. A total of 207 samples of soil fauna were collected by soil monolith and pitfall trap methods over two years of evaluation in four municipalities. Based on edaphic fauna data, Shannon-Wiener (H’), Pielou (J), Dominance (D), Margalef and Fisher Alpha (α) indices were generated, in addition to the average richness and abundance. Data from NTs were submitted to analysis of variance and compared by Tukey's test (p > 0.05). The NF was used as a reference and compared with the agriculture system by Dunnett test (p > 0.05), and regressions between soybean productivity and diversity indices. The H’, Margalef, α indices, and average richness for soil fauna sampled by soil monoliths followed the productivity gradient NTH > NTM > NTL, showing a positive correlation with the increase of soybean productivity. NTH has a diversity index similar to that of NF. Soybean productivity is affected by the richness and diversity of edaphic fauna, but abundance was not sensitive in predicting treatments under no-tillage; Fisher's alpha index was more sensitive in treatment separation with soil monoliths. The environmental variables aluminum, organic matter, phosphorus, potassium and penetration resistance affect the fauna edaphic.

氮沉降对杉木人工林土壤可溶性有机质数量和结构的影响

氮沉降作为现在乃至未来气候变化的趋势之一，其可能深刻影响土壤可溶性有机质的数量和结构。选取我国中亚热带杉木人工林不同深度土壤（0-10 cm和10-20 cm）进行氮沉降试验，利用光谱技术研究氮沉降对土壤可溶性有机质数量和结构的影响。试验设对照（CT，0 kg hm^-2 a^-1）、高氮（HN：80 kg hm^-2 a^-1）、低氮（LN：40 kg hm^-2 a^-1）3种处理。结果表明：（1）在0-10 cm和10-20 cm土层，HN、LN处理的土壤可溶性有机碳和可溶性有机氮含量显著高于CT。（2）在0-10 cm和10-20 cm土层，1月时HN、LN处理的芳香性指数和腐殖化程度都显著高于CT，而4月时HN、LN处理的芳香性指数和腐殖化程度都显著低于CT。除了氮含量的直接影响外，RDA （冗余分析）表明，两土层中土壤含水量、pH和土壤有机碳是驱动氮沉降对土壤DOM数量和结构的重要环境因子。因此，氮沉降对土壤DOM的影响是复杂的，未来尤其应该注重氮沉降对生态系统影响的季节模式。;Nitrogen deposition, in relation with cliamte change, is anticipated to increase in the following decades. It is a potential factor that might profoundly affect ecosystem functioning. Enhanced nitrogen deposition might result in stoichiometric imbalance or other changed soil environment, and thereby affect plant growth and soil processes. Soil DOM (dissolved organic matter) plays an important role in ecosystem biogeochemical cycles. It is central to the questions of carbon sequestration in soils and nutrient availability to microorganisms. For example, in the early stage of plant litter decomposition, non-structural compounds are lost to soils mainly by the vehicle of DOM, which in return forms mineral-stabilized soil organic matter. Soil DOM is thus often considered to be a senstitive indicator of the interaction among plant, soil and microorganisms. Although many experiments on nitrogen deposition have been reported, inconsistency still remains about how soil DOM will respond to nitrogen deposition, especially in subtropical China.. Natural evergreen broad-leaved trees make up the typical vegetation in the subtropical zone of China, but large areas of natural forests have been transformed to Cunninghamia lanceolata plantations. Therefore, it is critical that we should explore the effects of nitrogen deposition on the dynamic changes of soil DOM in these plantations. In this study, we conducted a mesocosm field experiment in a Cunninghamia lanceolata plantations that stimulated nitrogen deposition. DOM from soils of 0-10 cm and 10-20 cm depth were examined by spectroscopic characterization, to explore the effect of nitrogen deposition on the quantity and structure of soil DOM. Three treatments (three replicates per treatment) were assigned to 9 plots: CT (control), HN (80 kg hm^-2 a^-1) and LN (40 kg hm^-2 a^-1). The results showed that (1) compared with CT, nitrogen deposition significantly increased the quantity of soil DOC (dissolved organic carbon) and soil DON (dissolved organic nitrogen) for both 0-10 cm and 10-20 cm soil layers. (2) The aromaticity index and humification index of DOM from both 0-10 cm and 10-20 cm soil layers were significantly enhanced by nitrogen deposition treaments in January, whereas an opposite pattern were observed in April. Besides the direct impact of nitrogen content, RDA (redundancy analysis) revealed that soil moisture, pH and soil organic carbon content were also main drivers regulating soil DOM. Our study suggests that nitrogen deposition might regulate soil DOM in either a direct way or an indirect way. More attention should be paid on the seasonal pattern of the influence of nitrogen deposition on ecosytem functioning.

RADICULAR BIOMASS AND ORGANIC CARBON OF THE SOIL IN FOREST FORMATIONS IN THE SOUTHERN AMAZONIAN MESOREGION

ABSTRACT The soils of the Amazon region, despite being under one of the densest forests in the world, are mostly characterized by the low availability of nutrients, with litter being the main route of nutrient entry. The objective of this study was to quantify the biomass of fine roots in the dry and rainy seasons of the year, including the organic carbon of the soil, and to compare the results in different study environments. The study was carried out in environments of native forest and reforestation aged over 20 years, located in the municipality of Humaitá – AM state. To assess the root biomass, collections were carried out in two periods of the year: dry and rainy seasons. In each of the study areas, five trenches, 0.40 m deep by 0.40 m wide, were dug manually at depths of 0-5, 5-15, and 15-30 cm. For the organic carbon analysis, soil samples were collected in the form of clods at the same depths. The production of root biomass in the native forest environment occurred more intensely in the rainy season, reaching values of 8.19 t. ha-1, greater than 3.57 t. ha-1 found in reforestation. The density as a function of the soil volume showed that the highest concentration is found in the first 5 centimeters of depth, differing significantly in the 5-15 and 15-30 cm layers for native forest area. The organic carbon of the soil showed significance between the dry and rainy seasons for the natural forest environments and reforestation with genipap.

Influence of Arbuscular Mycorrhizae on the Development and Attack of Leaf-Cutting Ants in Clonal Seedlings of Eucalyptus urophylla x Eucalyptus camaldulensis

The present study aimed to evaluate the effect of the mycorrhizal association in the development and attack of leaf-cutting ants Atta sexdens (Linnaeus, 1758) in clonal seedlings of Eucalyptus urophylla x Eucalyptus camaldulensis hybrid. The treatments consisted of inoculated and uninoculated seedlings with 100 grams of sand containing spores from arbuscular mycorrhizal fungi (AMF) collected on native soil from four different areas of the amazon: native forest area (NF), permanent preservation area recovered to three years (PPA03), permanent preserved area degraded (PPAD) and permanent preservation area recovered to four years (PPA04). At 45 and 90 days after inoculation (d.a.i.), height, fresh and dry matter of shoot and root, root development, number of leaves, stem diameter and tolerance to leaf-cutting ants were evaluated. In the first group of plants (45 d.a.i.), mycorrhizal plants presented the higher root volume with the use of APP04, APP03 and NF all with 6.16 mm. For the second group of plants (90 d.a.i.), the highest root volume was also found on mycorrhizal plants with the soil of APP03 and control with 7.16 mm. For the attractiveness test of ants, 16 discs were taken from the non-inoculated seedlings. Regarding the disks of mycorrhizal seedlings with the soil of APP04, only 9 were taken. Although the use of AMF to stimulate plant resistance to attack by leaf-cutting ants is a new study, studies related to the influence of mychorrizas on plant development are quite common and the results presented in this study did not evidence the influence of mychorrizas on plant development. However, it was observed that the early inoculation of the seedlings can reduce the attractiveness of leaf-cutting ants by the seedlings of the hybrid Eucalyptus urophylla x Eucalyptus camaldulensis, already in the first 45 d.a.i of the seedlings and the inoculum used can interfere in this process.

Egg parasitoids of Thaumetopoea pityocampa (Den & Schiff.) (Lepidoptera: Thaumetopoeidae) and natural effectiveness in Terzioğlu Campus (Çanakkale)

The study was conducted in the natural forest area in Terzioğlu campus of Çanakkale Onsekiz Mart University in 2018. The purpose of the study was to determine the natural effectiveness of the egg parasitoids of Thaumetopoea pityocampa (Den & Schiff.) on red pines. Eggs collected in September and October were transferred into glass tubes, then they were placed in a climate chamber with 24±1Cº temperature and 60-70% r.h. Eggs were checked daily and emerged adults were transferred to new glass tubes to examine adult longevity. Total number of egg batches was 72 with a mean number of 250.27 eggs on each batch, and parasitism rate of eggs was 18.16% (1.13%-97.32%) from a total of 18018 eggs. Ratio of the species were 26% Anastatus bifasciatus Geoffroy, 32% Baryscapus servadeii Geoffroy and 42% Ooencrytus pityocampae Mercet. In 24±1Cº tempreature and 60-70% r.h., adult longevities of O. pityocampae, B. servadeii and A. bifasciatus were determined as 18.77, 8.46 and 8.85 days, respectively.

SOIL CARBON STOCK IN DIFFERENT USES IN THE SOUTHERN CONE OF MATO GROSSO DO SUL

This study aimed to assess the soil density (Sd) and the total organic carbon contents and stocks in different management systems and implementation times in the municipality of Iguatemi, MS, Brazil. A completely randomized design with four replications was applied to four areas: conventional tillage (CT), reformed pasture (RP), and degraded pasture (DP), in addition to a native forest (NF) area with no anthropic action. Disturbed and undisturbed soil samples were collected at depths of 0–0.05, 0.05–0.1, and 0.1–0.2 m. The determination of Sd and total organic carbon content (TOC) allowed calculating the carbon stock (Cstock), the stratification index (SI), and the carbon stock variation (ΔCstock), with subsequent multivariate analysis. The NF area presented the highest TOC contents at all depths compared to the managed areas, with a value of 17.45 g kg−1 at a depth of 0–0.05 m. The RP and NF areas showed similar SI, which was higher in PD, with a value of 2.54. Except for RP, the other managed areas showed a negative ΔCstock in the soil profile relative to the NF area. The RP and NF areas promoted the maintenance of TOC in the soil, while DP and CT compromised the edaphic quality.

Anthropogenic Factors Control the Distribution of a Southern Conifer Phytophthora Disease in a Peri-Urban Area of Northern Patagonia, Argentina

Several mid-sized urban areas have established boundaries overlapping with the distribution of Austrocedruschilensis (D.Don) Pic.Serm. & Bizzarri forests in Patagonia. These forests suffer a disease whose primary cause is the aggressive pathogen Phytophthora austrocedri. This study analyzes the factors related to Austrocedrus disease in an urban and peri-urban environment, showing that anthropogenic factors related to Phytophthora dispersion predominantly influence the disease distribution. The study was developed in urban and suburban areas of San Carlos de Bariloche county (Río Negro Province, Argentina). A database of requests to fell A. chilensis trees, from the Forest Department of Río Negro Province, was cleaned up and improved through satellite images analysis and field sampling. Data were analyzed in order to set up a layer of Austrocedrus disease presence. From this layer, and from anthropogenic and environmental layers (distance to houses, distance to roads, precipitation, slope, aspect, altitude, distance to water courses), a risk model was developed using the Maximum Entropy (MaxEnt) algorithm. In turn, data from the field sampling were assessed by contingency tables and chi square analysis. The results show that disease occurrence in San Carlos de Bariloche county is associated with the insertion of the urban network over areas of native forests. Distance to houses, distance to roads and distance to gardens with irrigation were the most important variables associated with the disease occurrence. A risk model was generated for the study area, which shows the current risk situation for the disease. Urbanization’s advance over the forest modifies key variables related to Phytophthora dispersion, such as the distance from cypress trees to houses and roads, thus progressively increasing the area at risk of becoming diseased. Based on these results, plausible measures and actions are proposed.

Estrutura e síndromes de dispersão da vegetação arbórea em floresta nativa e agrofloresta, na Amazônia Meridional: Structure and dispersal syndromes of forest and agroforest

The choice of native species used in the management of agroforestry systems for the recovery of anthropized environments, are fundamental for maintaining biodiversity and ecological processes. In this study, we evaluated the structural complexity and diversity of plants in a teak agroforestry, compared to a native forest tangent to the planted area. Thus, we set up 33 plots in the area of ​​native forest and 24 in agroforestry, both with dimensions of 10 × 10 m, at Fazenda Sao Nicolau, Cotriguacu, Mato Grosso, Brazil. We collected data on the structure of vegetation and calculated the descriptive phytosociological parameters of the community structure. We used i) PCoA to evaluate the floristic similarity between native forest and agroforestry, ii) GLM to determine the influence of the canopy opening on the vegetation structure, and iii) ANOVA to analyze the structural characteristics by dispersion syndrome. We registered 395 tree individuals belonging to 98 species and 35 families, including the exotic species Tectona grandis. We considered abundance and the basal area in relation to the dispersion syndrome, where we noticed, the zoocoria significantly higher when compared to anemocoria and autocoria. Thus, we consider the zoochoric dispersion syndrome as a factor that best explains the relationship between the types of forests in the Southern Amazon.

Density and morphological characterization of bacteria in integrated and exclusive production systems

The different integrated production systems can directly interfere with its bacterial community. The present study aimed to assess density, bacterial diversity and the influence of dry and rainy season in different integrated and an exclusive production system. The fallow and a native forest area was assessed to. Samples were collected in 2012 March and September. The isolation were carried out into Petri dishes containing DYGS medium. The number of colony forming units (CFU) was counted after 48 hours and. The bacterial density ranged between 106 and 107 CFU g-1 soil. The crop system affected the dynamics of the bacterial community only in the rainy season. The rainy season showed greater density of total bacteria when compared to the dry period regardless of the cropping system. The dendrograms with 80 % similarity showed thirteen and fourteen groups in the rainy and dry seasons. Isolates with the capacity to solubilize phosphate in vitro were obtained from all areas in the two seasons, but this feature has been prevalent in bacteria isolated during the rainy season.

An Analysis of the Impact of Forest Policy on Rural Areas of Chile

The relationship between the forest sector and the well-being of people that depend on it for their economic livelihoods in rural areas is of strong interest in forest policy. In this sense, Chile has developed a forest policy that has had positive impacts, particularly on economic and productive aspects, but also negative impacts, such as the reduction of natural forest area, biodiversity, and provision of ecosystem services, as well as the increase in social conflicts and land abandonment. However, there are few studies that have evaluated the impacts of forest policy on rural population and development of the territory. Therefore, the objective of this research is to evaluate the impacts of Chilean forest policy on rural communities, particularly in terms of demographic variables and indicators of community well-being. The study area corresponds to the Bio Bio and Ñuble Regions (Chile), and the analysis includes productive, demographic, socioeconomic, and educational characteristics of population. The results show that the forestry policy implemented was able to generate a significant increase in the proportion of forest area. However, when this increase is mainly of the type of exotic forest plantations, it is associated with a demographic and socio-economic detriment of the population in some counties of the study area.