Natural Forest Areas Research Articles

Causes and consequences of Cedrela odorata invasion in West African semi-deciduous tropical forests

Most of the West African forests have disappeared or have been deeply fragmented. This deforestation dynamic is still ongoing under a strong demographic pressure, forests being mostly replaced by agricultural lands. On the other hand, some reforestation projects are also undertaken, in particular by planting non-native species like Cedrela odorata. To our knowledge, this study is the first to investigate the causes and consequences of Cedrela odorata spread in West African natural forests. We studied a 400ha area of natural forest where 100ha of permanent plots have been affected by a major fire in 1983. Within these permanent plots, 21,444 trees were mapped, botanically determined and their diameters at breast height were measured in 2018. Using a bayesian hierarchical framework, we modelled the causes of the spread of Cedrela odorata in the studied plots, and its consequences on aboveground biomass and tree community diversity. Regarding the causes, the occurrence of Cedrela odorata is significantly linked to the fire occurence 25 years ago, to the proximity of the forest edge and to the presence of hydromorphic soils. Regarding the consequences, Cedrela odorata invasion doesn’t have any significant impact on the above-ground biomass but has a strong negative effect on the tree community diversity, as far as decreasing Simpson diversity in Hill numbers from 27 equivalent species in slightly invaded plots to 2 equivalent species in largely invaded plots. Our results highlight the long-lasting impacts of human disturbance (fire, Cedrela odorata introduction) on forest ecosystems and the need to use local species for ongoing reforestation plans in West African semi-deciduous forests.

APPLICABILITY OF THE SWAT HYDROLOGICAL MODEL IN THE MUCURI RIVER BASIN

ABSTRACT Land-use changes promote significant variations in streamflow regimes, and hydrological models allow studying their impacts. Based on this approach, this study aimed to assess the applicability of the SWAT model for different land-use scenarios and their respective impacts on the flow regime of the Mucuri River. The average monthly and daily water balance was generated after the calibration and validation of the SWAT model in the basin. Three land-use scenarios were analyzed in relation to the current land use, as follows: replacement of the agricultural area by the eucalyptus crop, replacement of the native forest area by the sugarcane crop, and replacement of pasture by exposed soil. The results showed that the SWAT model is adequate to simulate the land-use change and its impact on the flow regime of the Mucuri River; the replacement of agriculture by eucalyptus in the basin led to a decrease in the average and minimum reference streamflows; and the replacement of the forest cover by sugarcane and pasture by exposed soil provided an increase in the average and minimum reference streamflows.

Carbono orgânico e estoque de carbono do solo em diferentes sistemas de manejo

O presente estudo teve como objetivo avaliar os teores de carbono orgânico total (COT) e os estoques de carbono (EstC) em diferentes sistemas de manejo conduzidos ao longo do tempo no município de Iguatemi (MS), Brasil. Foi utilizado o delineamento inteiramente casualizado com quatro repetições, sendo estudadas quatro áreas situadas em uma mesma propriedade rural, conduzidas com diferentes sistemas de manejo, sendo elas: lavoura em sistema de preparo convencional, pastagem permanente e eucalipto, além da área de mata nativa sem ação antrópica. A coleta de solos foi efetuada nas camadas de 0-5, 5-10 e 10-20 cm, com realização das seguintes análises: densidade do solo (Ds), teores de COT, com posteriores cálculos do índice de estratificação (IE), EstC e variação do estoque de carbono (ΔEstC), tendo a área de mata como referência. Posteriormente as variáveis foram agrupadas em análise multivariada. Todas as áreas manejadas apresentaram valores de Ds acima do limite crítico, superiores à área de mata, chegando a 1,73 Mg m-3. A área de mata obteve teores e estoques de carbono superiores em todas as camadas, quando comparada às áreas manejadas, sendo que estas não apresentaram potencial de acúmulo de carbono no solo, apresentando ΔEstC negativo em todas as camadas avaliadas. Todas as áreas estudadas apresentaram IE superior a 1,00, com a área de mata superior às áreas manejadas, sendo estas semelhantes entre si. A análise multivariada formou dois grupos distintos, um contendo a área de mata e outro contendo os sistemas de manejo.

Growing Site Characteristics of Agathis labillardieri Warb in the Natural Forests of Siwi Momiwaren, West Papua

Agathis labillardieri Warb is one of the copal-producing tree species that only distributed in Papua. In connection with regional development, the existence of this species has been a significant concern. Therefore, it is necessary to study the characteristics of A. labillardieri Warb in their natural growing areas in the natural protected forest of Siwi Momiwaren. The data were collected by using the line plot method systematic sampling method with nesting plot. The data were then analyzed to determine the species relative density, frequency, dominance, important value index (IVI), and growth characteristics. The results showed that A. labillardieri Warb had the highest IVI at all levels of growth, with the highest diversity index at the seedling level of 3,49. When viewed from the relationship of the presence of species with the characteristics of the growing site, the content of Mg and Na significantly affected the presence of this species in the natural forest area of South Manokwari Siwi Momiwaren.Keywords: Agathis labillardieri Warb, growing site characteristics, Siwi Momiwaren, West Papua

Associação entre síndrome cardiopulmonar do hantavírus em humanos e configuração da paisagem na região do Cerrado de Minas Gerais, Brasil

The objective of this study was to analyze the spatiotemporal distribution of 193 autochthonous cases that were confirmed as hantavirus cardiopulmonary syndrome (HCPS) from 1998 to 2007 and its association with landscape configuration in the Cerrado region of Minas Gerais, Brazil. Among the 193 autochthonous cases, the probable sites of infection (PSI) of 129 cases (66.8%) were geoprocessed. We then evaluated the association between the HCPS cases and landscape variables through a multivariate analysis of the main components. Particularly, the mesoregion of Triângulo Mineiro/Alto Paranaiba had 130 autochthonous cases (67.3%). In addition, the chance of conglomeration of cases in municipalities located in this mesoregion was greater than that in other mesoregions. HCPS cases were positively associated with the increase in the area of planted pastures and natural forests in the Cerrado region. Rice, beans, maize, and sugar cane cultivations were less associated with HCPS. We concluded that the changes in the Cerrado ecosystem due to agricultural activities propitiate the maintenance of rodent populations and HCPS virus reservoirs. Additional training for health professionals for early diagnosis and reduction of the causes of the disease must be carried out in the endemic areas of Minas Gerais.

Conservation value of national forest roadless areas

AbstractConservation scientists call for establishing additional protected areas amidst ongoing threats of expanding human development. Nevertheless, some existing protected areas are being downsized and demoted of their existing conservation protections. In 2001, the Roadless Area Conservation Rule prohibited road construction and timber harvest in 240,000 km2 of inventoried roadless areas (IRAs) located on United States Department of Agriculture Forest Service lands. IRAs represent a non‐legislative protected status that is in jeopardy of conservation demotion or “degazettement,” and few national protected area assessments recognize the IRA designation. Since the rule's conception two decades ago, little research has been conducted to assess the conservation values of IRAs and the values they could add to the existing system of highly protected areas in the continental United States. To increase understanding of these conservation values, we assessed three aspects of roadless areas: (a) how wild and intact are IRA lands compared to state, national, and protected lands, (b) how do IRAs complement the size, connectedness, and representation of protected lands, and (c) how do IRAs contribute to protection of important ecosystem services (drinking water and annual carbon capture)? Through this analysis we found that many IRAs are among the most wild, undeveloped areas both in the nation and within their respective states. IRAs increase the size of—and reduce isolation between—protected areas, likely buffering them from external stressors. In some places, IRAs protect watersheds that deliver drinking water to hundreds of thousands of people. IRAs also add significantly to the total carbon captured by existing protected areas. The results of our evaluation demonstrate the potential of IRAs to contribute to the conservation value of the U.S. protected area system and to deliver important ecosystem services.

Native forests but not agroforestry systems preserve arbuscular mycorrhizal fungal species richness in southern Ethiopia

The rapid conversion of native forests to farmland in Ethiopia, the cradle of biodiversity, threatens the diversity of the arbuscular mycorrhizal fungi (AMF) pivotal to plant nutrition and carbon sequestration. This study aimed to investigate the impact of this land-use change on the AMF species composition and diversity in southern Ethiopia. Soil samples were collected from nine plots in each of three land-use types: native forest, agroforestry, and khat monocropping. The plots of the three land-use types were located adjacent to each other for each of the nine replicates. Three 10 × 10m subplots per plot were sampled. AMF spores were extracted from the soil samples, spore densities were determined, and species composition and diversity were evaluated through morphological analysis. Both spore density and species richness were statistically significantly higher in the native forest than in the agroforestry plots with no clear difference to khat, whereas the true diversity (exponential of Shannon–Wiener diversity index) did not differ among the three land-use types due to high evenness among the species in agroforestry. In total, 37 AMF morphotypes belonging to 12 genera in Glomeromycota were found, dominated by members of the genera Acaulospora and Glomus. The highest isolation frequency index (78%) was recorded for Acaulospora koskei from native forest. Consequently, the agroforestry system did not appear to aid in preserving the AMF species richness of native forests relative to perennial monocropping, such as khat cultivation. In contrast, the native forest areas can serve as in situ genetic reserves of mycorrhizal symbionts adapted to the local vegetative, edaphic, and microbial conditions.

Land Use Change in the Continental United States: Are There Tipping Points?

Land use in US is driven by multiple forces operating at the global level, as income and population growth, yield and productivity improvement, trade policy, climate change, and changing diets. Future land use have implications for biodiversity, run-off, carbon storage, ecosystem values, agriculture, and the broader economy. We investigate those forces in the US and their implications from a multisector, multisystem dynamics (MSD) perspective focused on understanding dynamics and resilience in complex interdependent systems. Historical trends show slightly increased grassland and natural forest areas and decreases in cropland. We project these trends are intensified under higher pressures for agriculture land or reduced under lower pressures, with no evidence of tipping points toward larger agricultural land abandonment or deforestation. However, US sectoral output and trade, fertilizer use, N2O and CH4 emissions from agriculture activities and CO2 emissions from land use changes are substantially impacted under several land use forcing scenarios.

Pedoindicators attributes in the variation of CO2 efflux in Indian black earth and non-anthropic soils

In the last decades, the studies involving the mechanisms of the CO2 emissions dynamics have been studied in several ecosystems with varied soil classes. The objective of this study was to evaluate the relationship between physical and chemical attributes of soils and the variation of CO2 efflux in Indian Black Earth (IBE) and non-anthropogenic soils in the Amazon. The study areas are located in the southern region of Amazonas, specifically in the municipalities of Humaitá and Apuí. Respectively in the natural field and forest areas, grids with dimensions of 70 m x 70 m and 10 m regular spacing between sample points, in the depth of 0.0–0.20 m, totaling 64 samples were delimited. In the IBE area, a 42 x 88 m grid was established, marking points at a 6 x 8 m spacing, totalizing 88 sampling points in the depth of 0.0–0.2 m. The soil physical analyzes performed were bulk density, soil penetration resistance, macroporosity, microporosity, total porosity and texture, and the soil chemical analyzes were composed by organic carbon, organic matter and carbon stocks. The soil CO2 emission (FCO2) was recorded with a portable automated LI-COR soil flow system (LI-8100). The soil temperature (Tsolo) was monitored concomitantly with the soil CO2 emission evaluations using a temperature sensor that is an integral part of the LI-8100 system. Soil moisture was recorded using a Time Domain Reflectometry (TDR) apparatus - Campbel® Hydrosense ™ Campbell Scientific. The data were submitted to descriptive statistical analyzes and multiple linear regression with the pedotransfer functions model criterion. The study demonstrates the variation of physical and chemical attributes of the soil and its influence on CO2 efflux variation, since the different environments studied presented differentiated scales and attributes for each situation, due to the correlations presented.

Soil-water physical attributes under different managements systems in the humid tropics in Maranhão

This study was conducted to evaluate the physical properties modifications of an Oxisol under different conditions of use and management. The research was conducted at Fazenda Sítio Novo and in native forest area, respectively in the municipalities of São Benedito do Rio Preto/MA and Chapadinha/MA. The research followed a completely randomized design with 3 treatments and 4 replications, with the following uses and management: no-tillage (PD); conventional planting (CP) and native forest (MN). The following physical properties were analyzed: bulk density, porosity and soil moisture and penetration resistance at depths of 0.0-0.20 m and 0.20-0.40 m. The water properties analyzed were: basic infiltration velocity, total soil water capacity and vertical hydraulic conductivity. The soil presented higher density and low conservation of moisture in PD and PC. Native forest presented higher total porosity and higher conservation of soil moisture. Total soil water capacity was higher in MN (39.89 mm) followed by PC (25.33 mm) and PD (18.84 mm). The uses and management employed in the soils analyzed on the farm reflect the degradation of the physical properties of the soil in relation to native forest.

Object-oriented and fuzzy logic classification methods for mapping reforested areas with exotic species in Rio Canoas State Park—Santa Catarina, Brazil

Reforestation with exotic plans may alter the natural flora due to uncontrolled expansion of the inserted species. This study evaluated the potential of the object-oriented classification method using fuzzy logic algorithm for the differentiation of forest areas in intermediate/advanced stage and areas reforested with exotic species around the Rio Canoas State Park in Santa Catarina State of Brazil, using high spatial resolution SPOT6 imagery. The study region has regional importance for the preservation of mixed ombrophilous forest remnants and is belonging to the Biosphere Reserve of the Atlantic Rainforest, and hence, it is important to monitor the advance of exotic species in the region. The methodology consisted of the creation of the hierarchical network and process tree with numerous descriptor tests in Trimble Ecognition software, principal component analysis, multi-resolution segmentation algorithm and fuzzy logic functions. It was concluded that the use of principal components associated with the red band by a simple ratio of digital levels is extremely effective for identifying the areas reforested with exotic species. Fuzzy logic pertinence functions are the key in discriminating natural forest areas and areas reforested with exotic species in the study region accurately. The object-oriented classification was validated by points collected in the field and presented an overall accuracy level of 0.83 and Kappa index of 0.78, concluding that it is an efficient methodology in the delimitation of exotic species reforestation areas around Rio Canoas State Park.

Seed rain as an ecological indicator of forest restoration in the Pampa biome

This study evaluated seed rain in different forest formation soil uses in the Serra do Sudeste region, Pampa biome. Four area were selected: active restoration (Area 1), passive restoration (Area 2), eucalyptus commercial plantation (Area 3) and native forest (Area 4). Ten permanent collectors of 1 m² each were installed in each area, being suspended 1 meter above the soil surface. Collections were made monthly for twelve months in 2018. The analyzed variables were: the number of morphospecies, number of individuals, the indices of Margalef richness, Pielou evenness, Shannon diversity, Jaccard floristic similiarity, and possible correlations by detrended correspondence analysis (DCA). Total number of seeds sampled during the period was 239,988, distributed across 116 morphospecies. The area under active restoration (Area 1) did not differ statistically by the Kruskall-Wallis test (p < 0.05) of the native forest (Area 4) for the number of seeds. Area 1 presented a higher number of morphospecies and greater diversity of species, followed by Area 4. Seed rain can be a promising ecological indicator for the conditions of the present study.

The effect of the ‘Las Maquinas’ wildfire of 2017 on the hydrologic balance of a high conservation value Hualo (Nothofagus glauca (Phil.) Krasser) forest in central Chile

The large wildfires of January 2017 burned more than 500,000 ha, including areas of high conservation value native forest, in central Chile. Runoff, streamflow and water balance were measured in a native forest catchment for 7 years before and 2 years after the fires. The annual peak flows and runoff coefficients decreased after the fire as did summer flows and total streamflow. These reductions in flow were despite rainfall being higher in the two years after the fire than in the two years before the fire. The forest re-sprouted vigorously after the fire and evapotranspiration in the second year after the fire was approximately two thirds of the rate before the fire. While the forest water use is recovering rapidly, streamflow in the two years after the fire was reduced relative to the seven years before the fire. In the two years after the fires, more than 50% of rainfall is not accounted for by either evapotranspiration or by streamflow. Potential explanations for this gap in the water balance include recovery in storage after the fire and increased bypass flow below the measuring weirs.

USE OF DIFFERENT INFILTROMETERS TO ASSESS ENVIRONMENTAL DAMAGE CAUSED BY DIFFERENT LAND USES

The present work had an objective to compare the stable infiltration rate obtained by infiltrometers with reduced dimensions and varied forms in different land uses. The infiltration tests were carried out in areas planted with cowpea, crotalaria, pigeon pea and millet, as crops previous corn planting, and managed with no-tillage, minimum tillage and conventional tillage and native forest area. In order to compare and analyze the results of the stable infiltration rates obtained between the alternative infiltrometers and the considered standard, the criteria involving the standard error of estimation (EPE), the standard error of estimation adjusted (EPEa), the standard error of estimation adjusted by origin (EPEao) and coefficients of adjustments of the linear equations with their respective determination coefficients (R2) were used. It was verified that the double-ring reduced, single-ring and double square infiltrometers provided a water saving of 57.06%, 66.19% and 38.54% respectively, relative to the standard. The alternative infiltrometers overestimated the stable infiltration rate in relation to the standard. The single-ring infiltrometer obtained a stable infiltration rate correction equation that showed results very close to the standard and the best statistical indices of stable infiltration rate results were obtained by the reduced double-ring infiltrometer.

Agricultural activity: Legal Amazon: Ambiental degradation

Urban sprawl, agricultural and livestock sprawl, are the main activities involved in economic development in the Midwest and Northern regions of Brazil and are directly associated with the conversion of native vegetation areas to pasture formation and agricultural production. The objective of this work was to carry out a review research regarding the deforestation arc due to the pressure of the agricultural borders. Information about the production systems in the Arc of Deforestation was collected through bibliographic references and web graphics. From 1988 to 2018, 13.72% of forest cover occurred, which lost natural forest areas, mainly due to the implementation of agricultural and urban expansion activities in the Midwest and Northern regions of Brazil. Regarding production areas, observe all states that are part of the deforestation arc. It requires the adoption of measures aimed at environmentally sound production, trying to combine the conservation of the Amazon Forest's natural resources with agricultural production.

Análise de resíduos de produtos fitossanitários em erva-mate (Ilex paraguariensis) proveniente de áreas de sistema agroflorestal do Planalto Norte Catarinense

A erva-mate produzida em áreas de floresta é influenciada pelos fatores sombreamento, altitude e umidade do solo, os quais favorecem o diferencial de qualidade e sabor intitulado a esse produto. O planalto nortecatarinense caracteriza-se como uma das principais regiões produtoras de erva-mate em áreas de floresta noBrasil. Sendo assim, objetivou-se realizar a quantificação das áreas de florestas, utilizando imagens do satélite C-bers 4 e analisar, em amostras de erva-mate cancheada, indícios de contaminação por produtos fitossanitários visando subsidiar a indicação geográfica (IG) da cultura. Ensaios de multiresíduos de produtos fitossanitários foram realizados por meio de cromatografia a líquido/espectrometria de massa sequencial (LS/MS/MS) conforme métodos da AOAC (2012), e não foram encontradas contaminação por nenhuma das 151 substâncias avaliadas na análise. Dentre todos os usos das terras avaliados, 44% são de áreas de florestas nativas. A expressiva presença de áreas de floresta e ausência de contaminação por produtos fitossanitários na erva-mate cultivada nessa região favorece ainda mais IG da cultura.

Impact of logging operations on forest ecosystem in the Khantai mountain region and forest cover mapping

Forests in Mongolia yield low productivity and are vulnerable to disturbances from drought, fire, pests, and illegal logging. Such forests can quickly lose their ecological balance. Logging activities in these areas are limited in monitoring and controls. This study assesses two different logging operations for their natural regeneration capacity by comparing the composition of the soil, soil organisms, physical and chemical properties, and forest cover change after the completion of logging operations. The logging operations were analyzed in two different regions, the Khartsai and Tariakhtai threshold in Selenge soum, Bulgan province. A skyline logging operation was undertaken on Khartsai threshold in 1983 and a tractor logging operation (clear-cutting) on Tariakhtai threshold in 1987. After the completion of the logging, the forests were naturally regenerated. In 2002, soil samples were collected and soil organisms and physical and chemical properties were examined. Satellites images were also used to evaluate forest cover changes after the end of the logging operations. Significant differences in the naturally regenerated tree species in the skyline logging, tractor logging, and natural forest areas were observed. Average tree ring growth was 0.9 mm in the skyline logging site, 0.6 mm in the tractor logging site, and 1.2 mm in the natural forest. Based on forest cover changes observed in satellite images, the density of naturally regenerated tree species in the natural forest area was higher than that in the skyline logging area. In contrast, the latter recorded a higher density than that in the tractor logging area. Therefore, processing of satellite images of forest cover changes with high-resolution data provides valuable information for the local forest community and helps decision-makers in their further actions.

Riparian Reserves Promote Insectivorous Bat Activity in Oil Palm Dominated Landscapes

The expansion of oil palm agriculture has contributed to biodiversity loss in Southeast Asia and elsewhere in the tropics. Riparian reserves (areas of native forest along waterways) have the potential to maintain forest biodiversity and associated ecological processes within these agricultural landscapes. Using acoustic sampling, we investigated the value of riparian reserves for insectivorous bats in oil palm plantations in Sabah, Malaysian Borneo. We compared general bat activity, foraging activity, and species occupancy between riparian areas in forest and riparian reserves in oil palm plantations. Overall bat activity varied little between riparian reserves in oil palm and riparian forest. Rather, activity was greatest in areas with a high forest canopy, irrespective of how much forest was available within or outside the riparian reserve. Bat foraging activity, as well as the occupancy of two species, was greatest in the forest sites, and while bats were detected in the oil palm riparian reserves, both foraging and occupancy were more associated with topographic ruggedness than forest amount or height. Our results indicate that habitat structure within riparian reserves may be more important than reserve size for supporting insectivorous bat diversity within oil palm landscapes. These findings provide important insights into the extent of the ecological benefits provided by conservation set-asides in forest-agricultural landscapes in the tropics.

Specific Gravity and Dimensional Stability of Boron-Densified Wood on Three Lesser-Used Species from Indonesia

Effect of pre-treatment and compression ratio on specific gravity (SG) and dimensional stability improvement of three lesser-used wood species from natural forest area of North Kalimantan Province, Indonesia had been investigated. Hot soaking at 80 °C for 3 hours within 2 and 5% of boron solution was applied as pre-treatment, while compression ratio applied was 20 and 40% from the initial thickness. Densification was conducted using hot pressing machine at 30 kg/cm2 of pressure and 160 °C of temperature for 15 minutes. Specific gravity was measured gravimetrically, while dimensional stability was evaluated through thickness swelling and water absorption as the indicator. Results show that SG of densified wood was influenced by wood species and compression ratio, but not by pre-treatment applied; while dimensional stability was influenced by wood species, compression ratio, and pre-treatment. Specific gravity and water absorption of densified wood was improved significantly. Specific gravity increased 28.86‒63.03%, while water absorption decreased 12.80‒15.89%. Thickness swelling of 20% densified wood was lower than that of 40% densified wood.

Predation of the invasive gecko Hemidactylus angulatus Hallowell, 1854 (Squamata: Gekkonidae) by the wandering spider Ancylometes bogotensis Keyserling, 1877 (Araneae: Ctenidae) in Tolima, Colombia

We report the predation on the gecko Hemidactylus angulatus by the spider Ancylometes bogotensis, in the Tropical Dry Forest life zone located at Northern Tolima (Colombia). This short note is a contribution to the knowledge about the natural history of the referenced species because of the potential of A. bogotensis as a biological control agent of geckos that decreases its invasive potential. This is important due to the possibility to make populations of the gecko decline and to restrict the entry of these saurians to natural forested areas.