secondary species
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2021 ◽  
Vol 3 (2) ◽  
pp. 16-22
Author(s):  
Mihai Harpa ◽  
◽  
Lucian Dinca

Birch ssp. in the sub-Carpathians curvature can be found in composition with beech and other resinous species, unevenly distributed from the mountain peaks at around 1200 m down to 500-600, mainly from high hills to depressions at 600m, rarely seen on plain sites, crossing different geomorphological structures and overall accounting for 3857.1 ha. The main objective of the paper was to analyze the site and stand characteristics of Betula pendula ssp. Roth. in the subCarpathians curvature as followed: stand structure, stand types and stand site types, soils and different metrics, from growth to yields and its connectivity.The ecological adaptability to climate and soil and early fast growth, makes silver birch fulfill the overall requirements as a pioneer species, mostly naturally regenerated. Birch distribution is highly influenced by stand structure having low proportion in compositions, mean height of 15 m at age 50, and a diameter of 20m. Regarding the site, characteristics are more commonly found on fertile soils, corrugated or fragmented site type with a slope of 20-50° and it is distributed as secondary species in stands, averaging 750m in attitude, ranging from 500 to 1200m, 90% being in mixtures with other species with a mean annual increment of approximately 7 m³/year/ha regardless of stand site type. As an early successional species, it serves as a first colonizer but secondary species and quite often as an ecological instrument to improve the soil characteristics, biodiversity and prevent landslides in certain sites, lacking economic value other than fuel wood or other non-wood products.


2021 ◽  
Vol 130 (14) ◽  
pp. 143301
Author(s):  
N. M. Uchizono ◽  
A. L. Collins ◽  
C. Marrese-Reading ◽  
S. M. Arestie ◽  
J. K. Ziemer ◽  
...  
Keyword(s):  

Chemosphere ◽  
2021 ◽  
pp. 131807
Author(s):  
Hui Li ◽  
Yongliang Ma ◽  
Fengkui Duan ◽  
Tao Huang ◽  
Takashi Kimoto ◽  
...  

2021 ◽  
Vol 4 ◽  
Author(s):  
Roger Chambi-Legoas ◽  
Daigard Ricardo Ortega Rodriguez ◽  
Francisco de Marques de Figueiredo ◽  
Joel Peña Valdeiglesias ◽  
Percy Amílcar Zevallos Pollito ◽  
...  

Context: Gold mining is the most destructive activity in the natural forests of the Madre de Dios region in the southeastern Peruvian Amazon. Understanding the natural regeneration process of these degraded areas is necessary to develop forest restoration projects in such conditions.Aims: We aimed to evaluate forest recovery and identify the successional and structure patterns of vegetation governing natural regeneration over time.Methods: Structure, composition, richness, diversity, and successional status were evaluated in abandoned artisanal gold mine areas in Madre de Dios, southeastern Peru. Vegetation data were recorded in 61 plots of 250 m2 established in five sites varying from 1 to 19 years of abandonment. Vegetation in abandoned areas was compared with six undisturbed forests evaluated in previous inventories.Results: In the mining lands, tree density and basal area recovered quickly, while species richness and composition were slow. Forest recovery is an initial stage of transition from pioneer to early secondary species until at least 19 years after abandonment. The most abundant and frequent species were the fast-growing species Ochroma pyramidale and Cecropia engleriana. These species could be considered potential candidates to promote restoration plans. Pioneer species represented 63% of the number of species in plots of 1–4 years, 57% in plots of 5–7 years, and 50% in plots of 8–19 years. Early and late secondary species represented 34 and 16%, respectively, of the number of species in plots of 8–19 years. Abandoned mining and reference plots present less than 5% of species in common.Conclusion: Our results highlight a slow natural regeneration process in areas for up to 19 years after gold mining. Species from different successional statuses were identified as potential candidates for recovering vegetation in such areas. Our findings may have important implications for further research focusing on the ecological restoration in tropical forests severely degraded by gold mining.


2021 ◽  
Author(s):  
Christopher Cantrell ◽  
Vincent Michoud ◽  
Paola Formenti ◽  
Jean-Francois Doussin ◽  
Stephanie Alhajj Moussa ◽  
...  

<p>It is well known that the high population density of urban regions leads to significant degradation of the quality of the air because of the emissions of pollutants that are by-products of energy production, transportation, and industry. The composition and chemistry of urban air has been studied for many decades and these studies have led to detailed understanding of the factors controlling, for example, the formation of ozone, peroxyacetyl nitrate and other secondary species. In the last 20 to 30 years, significant progress has been made in reducing emissions of volatile organic compounds (VOCs) and oxides of nitrogen (NO<sub>x</sub>) in urban atmospheres. Substantial reductions in the abundance of secondary compounds, though, have been more elusive.</p><p>Research has continued to reveal more and more details of the complex processes involved in the atmospheric degradation of wide varieties of volatile organic compounds (VOCs) of anthropogenic and biospheric (BVOCs) origins. BVOCs include isoprene, monoterpenes and sesquiterpenes, and oxygenated VOCs (OVOCs, such as small alcohols). Emissions of BVOCs depend on several factors such as plant or tree species, temperature, and photosynthetically active radiation. They consist almost exclusively of unsaturated compounds with chemistry somewhat different from those of typical urban organic compound emissions. Oxidation of VOCs can lead to molecules of low volatility that are prone to uptake into the aerosol phase.</p><p>Recent studies conducted in megacities such as Paris, Mexico City, Los Angeles and those in China have led to significant advances in our understanding of the chemical evolution of urban plumes. However, important scientific questions remain on how mixing of anthropogenic and biogenic air masses modifies the composition of urban plumes and hence their impacts. Indeed, the proximity of cites to areas of strong biogenic emissions is not unusual. Many major cities at mid-latitudes are surrounded by forested areas.</p><p>ACROSS (Atmospheric ChemistRy Of the Suburban foreSt) is an integrative, innovative, multi-scale project awarded under the “Make Our Planet Great Again” (MOPGA) framework that seeks to definitively improve understanding of the impacts of mixing urban and biogenic air masses on the oxidation of atmospheric VOCs. The ACROSS working hypothesis is that this leads to changes in the production of oxygenated VOCs whose properties (e.g. vapor pressures) alter their importance in incorporation into SOA and their roles in production of ozone and other secondary species. Changes are also expected in the efficiency of radical recycling affecting the atmospheric oxidative capacity. Particularly important is NO<sub>x</sub> transport to suburban biogenic environments and the resulting modification of key chemical processes.</p><p>A key highlight of ACROSS is an intensive, multi-platform measurement campaign in the summer of 2022. It will use instruments staged on an airborne platform, a tower in the Rambouillet Forest near Paris, and other ground sites. The data collected from this campaign will be analyzed and studied to extract information about tropospheric oxidation chemistry generally, but also changes observed in the situation of mixed urban and biogenic air masses.</p><p>This presentation will summarize plans for the ACROSS campaign.</p>


2021 ◽  
Author(s):  
Lya Lugon ◽  
Karine Sartelet ◽  
Youngseob Kim ◽  
Jéremy Vigneron ◽  
Olivier Chrétien

This study presents the new version of the local-scale model MUNICH, capable to represent the formation of secondary species in gas and particulate phases. A sensitivity test is performed to investigate the formation of secondary aerosols in streets.


2021 ◽  
Author(s):  
Anders Hallan ◽  
Francesco Criscione ◽  
Alexander Fedosov ◽  
Nicolas Puillandre

The deep-sea malacofauna of temperate Australia remains comparatively poorly known. However, a recent influx of DNA-suitable material obtained from a series of deep-sea cruises has facilitated integrative taxonomic study on the Conoidea (Caenogastropoda:Neogastropoda). Building on a recent molecular phylogeny of the conoidean family Raphitomidae, this study focussed on the genera Gladiobela and Pagodibela (both Criscione, Hallan, Puillandre & Fedosov, 2020). We subjected a representative mtDNA cox1 dataset of deep-sea raphitomids to ABGD, which recognised 14 primary species hypotheses (PSHs), 9 of which were converted to secondary species hypotheses (SSHs). Following the additional examination of the shell and hypodermic radula features, as well as consideration of bathymetric and geographic data, seven of these SSHs were recognised as new to science and given full species rank. Subsequently, systematic descriptions are provided herein. Of these, five are attributed to Gladiobela (three of which are endemic to Australia and two more widely distributed) and two are placed in Pagodibela (one endemic to southern Australia and one widespread in the Pacific). The rarity of many ‘turrids’ reported in previous studies is confirmed herein, as particularly indicated by highly disjunct geographic records for two taxa. Additionally, several of the studied taxa exhibit wide Indo-Pacific distributions, suggesting that wide geographic ranges in deep-sea ‘turrids’ may be more common than previously assumed. Finally, impediments to deep-sea ‘turrid’ taxonomy in light of such comparative rarity and unexpectedly wide distributions are discussed.


2020 ◽  
Vol 5 (2) ◽  
pp. 253
Author(s):  
Vinícius Staynne Gomes Ferreira ◽  
Patrícia Carneiro Souto ◽  
César Henrique Alves Borges ◽  
Amanda Lira Freitas ◽  
Danilo Brito Novais ◽  
...  

Species arboreal, native of the Atlantic Forest biome, Poincianella pluviosa var. peltophoroides (Benth.) L.P. Queirozis widely used in urban landscaping due to the beauty of its flowering and indicated for the recovery of degradedareas as an initial or pioneer secondary species. The objective of the study was to characterize the fruits and seedsbiometrically, thus helping in its conservation and improvement. The work was conducted at the Federal Universityof Campina Grande, campus of Patos-PB, and the fruits were collected manually in matrices located on campus, usingas a selection criterion those who were mature. To obtain the biometric data, the fruits were selected and separated100 fruits and 100 seeds at random. To measure the biometric variables (length, width and thickness) of the fruitsand seeds, a digital caliper with a precision of 0.1 mm was used and then the amplitude of the classes of each analyzedvariable was calculated. The results showed that the fruits presented variation in the length of 4.51 to 10.53 cm,however, the predominance of fruit frequency was in the class of 6.03-6.77 cm. The seed length varied from 0.918 to1.208 cm, with a higher incidence in the class of 1.064-1.112 cm, where it concentrated about 45% of the seeds. It isconcluded that the fruits Poincianella pluviosa var. peltophoroides presented greater uniformity in the variable lengthand their seeds presented greater uniformity in the biometric variables in which they were evaluated, being this afavorable criterion for its propagation.


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