Top 10 - May
Posted on 2021-06-111-Seasonally dry tropical forest temporal patterns are marked by floristic stability and structural changes
Cléber Rodrigo de Souza, Alisson Borges Miranda Santos, Vinícius Andrade Maia, Gabriela Gomes Pires de Paula, Nathalle Cristine Alencar Fagundes, Polyanne Aparecida Coelho, Paola Ferreira Santos, Jean Daniel Morel, Paulo Oswaldo Garcia, Rubens Manoel dos Santos
Abstract
Background: Seasonally Dry Tropical Forests (SDTF) are recognized by their great biological diversity, but little is known about their temporal patterns, which may be crucial in a changing world. Here we aimed to characterize the SDTF dynamic patterns in floristic and structural changes, and also to evaluate shifts in dynamic rates and structural attributes such as richness, number of trees and biomass. Our hypothesis is that SDTF tree communities have their dynamic characterized by temporal fluctuations related to an instability pattern, in according to the already found for others tropical forests. For this we used a data of 42 400 m² plots in three fragments in the Brazilian Arboreal Caatinga, measured in 2005, 2010 and 2015. We evaluated temporal changes in richness, species composition, trees density, biomass and rates of tree mortality and recruitment; and also rates of biomass gain and loss.
Results: We found a pattern of floristic composition stability, but with changes in structure and dynamics. There was a tree density decrease driven by constant mortality and by recruitment decrease, and biomass increase due to decrease in biomass loss and to increase in biomass gain. The biomass increase was main related to a small set of dominant species that are the most representative in the community dynamics.
Conclusion: SDTF dynamics are related to stability in species composition, but with structural changes towards higher biomass stocks. The results are main related to community dynamics and to SDTF attributes such as climatic seasonality that drives the local ecological processes.
Keywords: Biomass increase; Caatinga Domain; communities stability; ecological dominance
2-Biochemical attributes and establishment of tree seedlings in soil after Urochloa decumbens cultivation in soil with deposition of iron mining residues
Alexandre Carvalho Ribeiro Junior, Aline Oliveira Silva, Éder Rodrigues Batista, Filipe Sales Naves, Flávio Araújo Pinto, Jessé Valentim dos Santos, Marisângela Viana Barbosa,Ingrid Fernanda Santana Alvarenga, Marco Aurélio Carbone Carneiro
Abstract
Background: D
The recovery of areas impacted by mining activities is a major challenge and requires knowledge of how the biological and biochemical processes of the soil as well as the establishment of plant species are affected by mining residue. In this work, the influence of deposition of iron mining mud and tailings on soil biochemical attributes and the initial development of tree seedlings was studied in a simulated event in the greenhouse. Pots (n = 27) with natural soil (2.0 kg) received deposition (280 mL) of iron mining mud or tailings and by three-month was cultivated with Urochloa decumbens. At the end of this period, part of the pots was sampled and the soil biochemical activities were evaluated. Then tree seedlings (Schinus terebinthifolius and Eremanthus incanus) were planted and cultivated for a year, when then shoot (SDW) and roots (RDW) dry weight were evaluated.
Results: Deposition of iron mining mud and tailings did not affect microbial biomass carbon or basal soil respiration, however both conditions reduced (p < 0.05) β-glucosidase activities by up to 30%, and the easy extractable glomalin by about 19%. In addition, the mud deposition reduced (p < 0.05) the SDW and RDW of S. terebinthifolius by about 21% and 24%, respectively. Nevertheless, Uruchloa decumbens and Eremanthus incanus had no variation in dry weight production between treatments, so they have good ability to grow settle in soil affected by mining residue.
Conclusion: This study shows that the sequential planting of U. decumbens and E. incanus can be an alternative for use in environments with deposition of iron mining tailings.
Keywords: Degraded Areas, Soil Bioindicators, Revegetation, Dam collapse, Enzymatic activity.
3- Controlled release fertilizer in the rooting and performance of clones of Paratecoma peroba
Emanuel França Araújo, Elzimar de Oliveira Gonçalves, Aline Ramalho dos Santos, Elbya Leão Gibson, Marcos Vinicius Winckler Caldeira, José Eduardo Macedo Pezzopane
Abstract
Paratecoma peroba is a native forest species of great economic and ecological interest, currently at risk of extinction. In addition to the difficulty of finding adult individuals of this species, plant production is limited, so the use of mini-cuttings can facilitate the spread of P. peroba. Thus, the objective of this study was to analyse the effect of different doses of controlled release fertilizer (CRF) on rooting, growth, photosynthetic metabolism and nutritional balance of P. peroba clones propagated by mini-cuttings. Five doses of CRF (0, 2, 4, 6 and 8 kg.m-3) were tested, arranged in a completely randomized design with 12 repetitions and each repetition consisted of eight clones. Evaluations were carried out in the three stages of clones production: 1) Survival at 60 days in a greenhouse, 2) Rooting at 105 days in a shade house; and 3) Evaluation Productivity index, morphological variables, physiological metabolism, and nutritional through macronutrient contents, diagnosis and recommendation integrated system (DRIS) indices and the average nutritional balance index of clones at 120 days in the area of hardening. There was no influence of CRF on survival and rooting of mini-cuttings. The CRF favoured a higher productivity index, vegetative growth and physiological activity of the clones. The 6 kg.m-3 dose was sufficient to obtain nutritionally balanced clones.
Keywords: Adventitious rooting, Mini-cutting, Gaseous exchanges, Fertilization, DRIS
4-Mini-cutting of Plathymenia reticulata benth. with mini-stumps conducted in suspended seedbed and tubes
Giovanna Campos Mamede Weiss de Carvalho, David Pessanha Siqueira, Renata de Deus Silva, Maria Kalyane Farias da Silva, Deborah Guerra Barroso
Abstract
Background: Despite the importance of Plathymenia reticulata for forestry and ecological purposes, a protocol for the vegetative propagation of the species remains unclear mainly due to the low adventitious rooting of the propagules of the species. In this sense, this work aimed to evaluate the rooting of mini-cuttings of juvenile materials of P. reticulata and our hypothesis: (1) maintaining propagules under mist chamber for different periods affects the rooting process; (2) the mini-stump management system due to the restriction of the root system affects the production of mini-cuttings and the quality of clonal seedlings.
Results: It was not necessary for more than 30 days in a mist chamber to induce rooting. The highest percentage of rooting was obtained 50 days after staking. Mini-gardens set up in suspended seedbed and tubes (280 cm3) had the average mini-cuttings productivity of 4.32 and 2.06, respectively, over 270 days of exploration (monthly collections). At 120 days after staking, there was no difference in the survival and in the final quality of clonal seedlings produced. However, clonal seedlings from mini-garden in tubes had higher height, leaf area, and number of first-order roots. Regardless of the mini-garden management, the clonal seedling production index was 50%.
Conclusion: We can conclude that P. reticulata seedling production via mini-cutting technique is possible.
Keywords: Adventitious rooting, Cloning, Native forest species, Vegetative propagation
5- Potential distribution of two lynx species in europe underpaleo climatological scenarios and anthropogenic climate change scenarios
Akin Kiraç
Abstract
Background: Today’s European fauna was formed under the influence of Paleoclimatic change. The distribution of two wild cat species of Europe, Lynx pardinus and Lynx lynx, 22,000 and 6,000 years ago were determined by the MaxEnt method in relation to the Paleoclimatological scenarios (LGM and Mid-Holocene) and fossil records. Then, the current climate conditions and their distributions under the effect of anthropogenic climate change scenarios were analyzed with the current existence records.
Results: It was determined that these two wild cats were distributed according to preys on which they specialized, rather than the climate change that lasted for thousands of years. It was observed that Lynx Pardinus, which specialized only on European rabbit hunting, could not expand its distribution from past to present. Lynx lynx, on the other hand, expanded its distribution throughout the Palearctic region and adapted to different ecosystem varieties by means of its specialization on many preys from mouse to moose. Based on the climate envelope model results created with the help of MaxEnt which considers anthropogenic climate change scenarios (RCP2.6, RCP4.5, RCP6.0 and RCP8.5 2070) and today’s data of two existing Lynx species, suitable habitats for L. pardinus will decrease and suitable habitats will emerge in Western France. L. lynx , on the other hand, will limit its wide distribution to the North, except for the Alps, the Carpathians and the Caucasus, which will serve as refugial areas.
Conclusion: These results therefore require that measurements such as reducing climate change impacts over the next 50 years, protecting existing and potential habitats in advance, and reducing anthropogenic impact should be enforced.
Keywords: Lynx, Fossil, Climate Envelope Model, MaxEnt, Anthropogenic Impact
6- Canopy recovery four years after logging: a management study in a southern brazilian secondary forest
Janine Kervald Likoski, Alexander Christian Vibrans, Daniel Augusto da Silva, Alfredo Celso Fantini
Abstract
Background:Understanding forest dynamics after logging is essential to define forest management cycles and intensities. In secondary forest, especially in the Atlantic Forest Domain, these studies are still scarce. Monitoring of the canopy structure after tree harvesting can be performed by hemispherical photographs, where canopy opening is commonly analyzed. This study evaluated changes in canopy opening four years after tree harvesting in a secondary Atlantic Rainforest in southern Brazil. We used hemispherical photographs to determine the Canopy Openness (CO), Leaf Area Index (LAI), and Diffuse Fraction of Photosynthetically Active Absorbed Radiation (FAPARdif) in eleven permanent plots.
Results:We found that harvesting resulted in a momentary increase in canopy opening and light availability in the understory. Four years after harvesting, CO, LAI and FAPARdif recovered or even exceeded the original values of the forest. We observed a significant correlation between CO and number of trees harvested with DBH > 30 cm. Weak correlations were found between these canopy related variables and the logging intensity.
Conclusion:In conclusion, we recognized that changes of CO, LAI and FAPARdif after timber harvesting presented short duration. This indicates that the applied logging intensities, 21.8 to 51.1% of the total basal area, did not exceed the resilience of the forest canopy and it’s recovering four years later. However, additional studies should be carried out to observe vegetation dynamics, such as species composition, vertical structure, productivity and community stability, in order to improve management schemes of secondary stands in the Atlantic Forest.
Keywords: Atlantic Forest, canopy openness, leaf area index, diffuse fraction of photosynthetically active absorbed radiation, sustainable forest management
7-Genetic control of productivity and genotypes by environments interaction for Eucalyptus dorrigoensis in southern Brazil
Leonardo Vannucchi Munhoz, Osmarino Pires dos Santos, Brigida Maria dos Reis Teixeira Valente, Evandro Vagner Tambarussi
Abstract
Background: Eucalyptus dorrigoensis withstands cold weather and the occurrence of frost, making it a potential species for improvement programs in Southern Brazil where such conditions occur. However, the use of the species is still uncommon and its genetic variability remains poorly understood.d.
Results: For site called Sertão Santana, the narrow sense heritability ranged from 0.46 (H) to 0.64 (MAI) and for Lavras do Sul it ranged from 0.38 (H) to 0.47 (MAI). The coefficient of genetic variation varied from 8.1% (H) to 26.1% (MAI). There is significant genetic correlation between DBH and MAI, reaching a value of 0.97. The GxE interaction was significant and mostly complex (78.7%). The best genetic materials for each environment, along with the most stable genetic materials, were identified. In addition, a thinning simulation was performed and the genetic gains for Sertão Santana and Lavras do Sul were 12.62 and 7.43%, respectively.
Conclusion:The studied populations have genetic variability that can be used in breeding programs by selecting among progenies and individuals within progenies. The GxE interaction is complex, and as such, the best genetic material should be selected independently for each site. The results of this study have practical implications for the companies and offer advances in knowledge of the species for breeding programs.
Keywords: BLUP, Genetic Correlation, GGE Biplot, Quantitative Genetics, Tree Breeding
8- Leaflet phenotypic plasticity in three woody species in two strata of a gallery forest
Jamile dos Santos, Ricardo Antonio Marenco, Wendy Carniello Ferreira, Daniela Pereira Dias
Abstract
Background: Along the vertical canopy profile, natural light availability is variable and may induce leaves morphophysiological changes due to phenotypic plasticity. Morphological changes in juvenile and adult leaflet of compound leaves of plant species is still poorly understood, including in woody species of gallery forests. The present study evaluated the leaflet morphophysiological characteristics and plasticity index of three woody species in canopy and understory leaves in a gallery forest.
Results: All morphophysiological characteristics varied within species (Myracrodruon urundeuva Allemão, Copaifera langsdorffii Desf. and Tapirira guianensis Aubl.). The leaflets of canopy trees showed significantly higher values of petiole length (PL) and diameter (PD), leaflet thickness (fresh - FT and dry - DT), specific leaf mass (SLM), in relation to understory leaflets. On the other hand, relative water content (RWC) did not change between adult trees and saplings, except for T. guianensis. The plasticity index of leaflet characteristics varied significantly within species. Plasticity index of three morphophysiological characteristics (PL, PD and DT) varied between species. PL and PD had the highest plasticity index values across species, whereas RWC had the lowest plasticity.
Conclusion: Plasticity index of the tree species associates these leaflet morphophysiological traits (PL, PD and DT) with variations in the physical environment between strata of a gallery forest.
Keywords: Brazilian savanna, leaf structure, specific leaf mass, relative water contente
9- Study on rare and endangered plants under climate: maxent modeling for identifying hot spots in northwest China
Hua Zhang, Haoxiang Zhao
Abstract
Background:Climate warming has caused substantial changes in temporal and spatial environmental patterns. The study on hot spots of rare and endangered plants in Northwest China under predicted climate change can provide a scientific reference for the restoration and reconstruction of those degraded habitats, as well as the improvement of the protection systemin Northwest China.
Results:Based on MaxEnt algorithm, 813 effective distribution records and 11 environmental factor variables of rare and endangered plants in Northwest China, this study identified the changes of biodiversity hotspots of rare and endangered plants in Northwest China under predicted climate change. The results showed that: (1) the prediction accuracy of MaxEnt model is high, the area under the curve (AUC) is 0.876, and the total suitable area for potential geographical distribution of rare and endangered plants in Northwest China is 137.96×104km2, mainly including Western and Southwestern Xinjiang, Southern Gansu, parts of Eastern and Southern Qinghai Province, and Southern Shaanxi Province; (2) altitude, temperature and precipitation are the main environmental factors affecting the hot spots of rare and endangered plants in Northwest China; (3) under four climate change scenarios in the future, with the increase of emission scenarios from low to high forcing, Xinjiang would have the most obvious loss of hot spots of rare and endangered plants in Northwest China, and the most obvious increase of which would occur in Qinghai and Gansu provinces.
Conclusion: Under the climate change scenario in the future, with the emission scenario increasing from low forcing to high forcing, the most obvious loss of the hot spots of rare and endangered plants in Northwest China happens in Xinjiang Province, and that of the most obvious increase occurs in Qinghai and Gansu provinces.
Keywords: Northwest China; rare and endangered plants; MaxEnt model; hot spots; climate change
10- Pull-out strength of glued-in GFRP rods in timber connections by using of epoxy resin reinforced by nanoparticles
Mehrab Madhoushi
Abstract
Background:In timber structures, connections are the most important and critical section which supply the strength of each structural element. The aim of this study was evaluation the behavior of epoxy resin reinforced by nanoclay (at three levels) on the pull-out strength of glued-in GFRP rods in glulam. For this purpose, two rods with three lengths (50, 150 and 250 mm) and diameters (6.4, 12.7 and 19.1 mm) were inserted at two opposite sides of glulam blocks (with dimension of 8.89 x 8.89 x 29.94 cm) which were glued by epoxy resin. Samples underwent tensile testing and their tensile strength and shear strength were measured. The obtained data were analyzed statistically and the effects of studied factors on bond strength were evaluated.
Results:The results showed that the strength of bonding increased with the addition of a low amount of nanoclay, and the length of the rod had a greater effect than its diameter. Furthermore, the amount of nanoclay, rod length and diameter could not significantly affect simultaneously, the performance and strength of glued-in GFRP rods.
Conclusion: Nanoclay particle can be considered as a reinforcement for epoxy resin in glued-in GFRP rods and its effect may cause a considerable increase in the mechanical strengths of joints.
Keywords: Epoxy resin, Bonding Strength, GFRP, Glulam, Nanoclay