Response of woody species to different fire frequencies in semiarid rangelands of central Argentina

2012 ◽  
Vol 34 (2) ◽  
pp. 191 ◽  
Author(s):  
Daniel V. Peláez ◽  
Romina J. Andrioli ◽  
Omar R. Elia ◽  
Eliana E. Bontti ◽  
María A. Tomas
Keyword(s):  
Woody Species ◽  
Fire Frequency ◽  
Perennial Grasses ◽  
Moderate Intensity ◽  
Similar Response ◽  
Managerial Implication ◽  
Central Argentina ◽  
Canopy Area ◽  
Controlled Burns ◽  
The Individual

The aim of the study was to assess the effect of different controlled fire frequencies on cover, density and mortality of the most common woody species in semiarid rangelands of the Caldenal district of central Argentina over a 20-year period. The study comprised three fire treatments: (1) high fire frequency (controlled burns every 3–4 years; HFF); (2) low fire frequency (controlled burns every 8 years; LFF); and (3) unburned control. Repeated burns of moderate intensity, regardless of frequency, reduced the cover and the individual height and canopy area of the most common woody species. Their density was barely affected and the mortality rates were negligible with woody species producing new sprouts after each burn. The woody species under study had a similar response to the high- and low fire frequency treatments. A controlled burn every 3–4 years, permitted the control of woody species cover, height and canopy area, which in turn may favour the production of desirable perennial grasses. The important managerial implication is that the repeated use of controlled fires of moderate intensities in the autumn, given appropriate grazing management, is likely to be essential to maintain these rangelands.

Response of grass species to different fire frequencies in semi-arid rangelands of central Argentina

2013 ◽  
Vol 35 (4) ◽  
pp. 385 ◽  
Author(s):  
Daniel V. Peláez ◽  
Romina J. Andrioli ◽  
Omar R. Elia ◽  
Eliana E. Bontti ◽  
María A. Tomas ◽  
...  
Keyword(s):  
Basal Area ◽  
Bare Soil ◽  
Fire Frequency ◽  
Perennial Grasses ◽  
Moderate Intensity ◽  
Grass Species ◽  
Central Argentina ◽  
Controlled Burns ◽  
Arid Rangelands ◽  
Semi Arid

The study was undertaken to quantify the effect of different controlled fire frequencies on foliar cover, density, individual basal area, and mortality of the most common perennial grass species in the semi-arid rangelands of the southern Caldenal in central Argentina over a 20-year period. Cover of bare soil was also assessed. The study comprised three fire treatments: (i) high fire frequency (controlled burns every 3–5 years; HFF); (ii) low fire frequency (controlled burns every 8 years; LFF); and (iii) unburned control (C). Fire treatments, regardless of frequency, induced an increase in foliar cover and density in desirable grasses, no changes in intermediate grasses, and a decrease in undesirable grasses. Individual basal area tended to be higher for desirable grasses and lower for intermediate and undesirable grasses when subject to fire. Most of the species under study exhibited higher mortality rates in the HFF treatment than in the LFF and C treatments. The results of the study suggest that recurrent controlled burns of moderate intensity may favour the herbage production of desirable perennial grasses. This, in turn, assuming appropriate grazing management, may have a beneficial impact on livestock production. Nevertheless, given the effects of fire on the cover of bare soil and mortality of grasses, further research is needed in order to determine the appropriate fire frequency in terms of rangeland sustainability.

scholarly journals Influence of woody species on aerial growth of perennial grasses in semi-arid rangelands of central Argentina

Phyton ◽  
2014 ◽  
Vol 83 (1) ◽  
pp. 397-405
Author(s):  
Blazquez FR ◽  
DV Pel醗z ◽  
RJ ◽  
rioli ◽  
OR Elia
Keyword(s):  
Woody Species ◽  
Perennial Grasses ◽  
Central Argentina ◽  
Aerial Growth ◽  
Arid Rangelands ◽  
Semi Arid

Influence of Woody Species on Aboveground Biomass Production and Quality of Two Perennial Grasses in Semi-arid Rangelands of Central Argentina

2020 ◽  
Vol 51 (1) ◽  
pp. 90-98
Author(s):  
Blazquez Francisco Rubén ◽  
Daniel Valerio Peláez ◽  
Romina Jessica Andrioli ◽  
Omar Raúl Elia
Keyword(s):  
Biomass Production ◽  
Aboveground Biomass ◽  
Woody Species ◽  
Perennial Grasses ◽  
Central Argentina ◽  
Arid Rangelands ◽  
Semi Arid

scholarly journals Demographic Effects of Severe Fire in Montane Shrubland on Tasmania’s Central Plateau

Fire ◽  
2021 ◽  
Vol 4 (3) ◽  
pp. 32
Author(s):  
Judy A. Foulkes ◽  
Lynda D. Prior ◽  
Steven W. J. Leonard ◽  
David M. J. S. Bowman
Keyword(s):  
Woody Species ◽  
Fire Frequency ◽  
Fire Season ◽  
Burned Area ◽  
Large Area ◽  
Seedling Regeneration ◽  
Central Plateau ◽  
Conservation Area ◽  
Severe Fire ◽  
Representative Area

Australian montane sclerophyll shrubland vegetation is widely considered to be resilient to infrequent severe fire, but this may not be the case in Tasmania. Here, we report on the vegetative and seedling regeneration response of a Tasmanian non-coniferous woody montane shrubland following a severe fire, which burned much of the Great Pine Tier in the Central Plateau Conservation Area during the 2018–2019 fire season when a historically anomalously large area was burned in central Tasmania. Our field survey of a representative area burned by severe crown fire revealed that more than 99% of the shrubland plants were top-killed, with only 5% of the burnt plants resprouting one year following the fire. Such a low resprouting rate means the resilience of the shrubland depends on seedling regeneration from aerial and soil seedbanks or colonization from plants outside the burned area. Woody species’ seedling densities were variable but generally low (25 m−2). The low number of resprouters, and reliance on seedlings for recovery, suggest the shrubland may not be as resilient to fire as mainland Australian montane shrubland, particularly given a warming climate and likely increase in fire frequency.

scholarly journals Changes in the woody component of an East African savanna during 25 years

1999 ◽  
Vol 15 (5) ◽  
pp. 545-564 ◽  
Author(s):  
Claudius A. D. M. Van De Vijver ◽  
Charles A. Foley ◽  
Han Olff
Keyword(s):  
Woody Species ◽  
Original Data ◽  
Fire Frequency ◽  
Tree Density ◽  
Severe Drought ◽  
East African ◽  
Large Numbers ◽  
Northern Tanzania ◽  
Total Tree ◽  
Large Decline

Changes in density, structure and species composition of the woody component of the two predominant savanna types in Tarangire National Park, northern Tanzania, during a period of 25 y were investigated. The park is known for its large, increasing elephant numbers and high frequency of fires. In 1996 a study on woody species density, composition and age structure, which was first performed in 1971, was repeated, using the same transects and method. Access to the original data of 1971 allowed for a full comparison of the changes and an investigation whether these could be related to changes in elephant numbers and fire frequency. The total tree density declined during the 25 y, but the decline was not evenly distributed over the different height classes. Although the density of trees taller than 5 m declined significantly, the greatest decline occurred in the density of trees shorter than 1 m. The density of trees in the intermediate height class of 1–5 m did not decline. Although damage to trees by elephants increased during the 25-y period, c. 25% showed no browse damage and, except for some severely damaged trees, elephant damage was not found to reduce tree vigour. Elephants affected the size distribution of the savanna woody component much more than the density, while the data suggest no significant effect of fire on changes in tree density. The large decline in density of small trees was attributed to a severe drought in 1993. Based on large numbers of elephants during the past decades and on relatively low elephant impact on the total tree density, the present study suggests that the current elephant number of 2300 can be sustained in the park without causing detrimental effects, provided that their current range is maintained.

scholarly journals Stimulus Level during Endurance Training: Effects on Lactate Kinetics in Untrained Men

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Michael Tuttor ◽  
Simon von Stengel ◽  
Michael Hettchen ◽  
Wolfgang Kemmler
Keyword(s):  
Interval Training ◽  
Stimulus Level ◽  
Moderate Intensity ◽  
Time To Exhaustion ◽  
Lactate Kinetics ◽  
High Intensity Interval ◽  
Underlying Mechanisms ◽  
The Individual ◽  
Total Workload ◽  
Continuous Running

Background/Objective. Not only but particularly due to their time efficiency, High-Intensity Interval Training (HIIT) is becoming increasingly popular in fitness-oriented endurance sports. The purpose of this study was to determine the effect of a HIIT running program versus a Moderate Intensity Continuous Exercise (MICE) training running program (16 weeks each) on lactate kinetics in untrained males. Methods. 65 healthy but untrained males (30-50 years, BMI: 27.2 ± 3.7kg/m2) were randomly assigned to either an HIIT (n=33) or a waiting-control/MICE group (n=32). HIIT consisted of intervals and intense continuous running bouts at or above the individual anaerobic threshold (IANS, 95-110% of IANS-HR), while MICE focused on continuous running at 70-82.5% IANS-HR. Both programs were adjusted for “total workload”. Study endpoints were time to IANS and time from IANS till “time to exhaustion” (TTE) as assessed by stepwise treadmill test. Results. In both exercise groups time to reach IANS (MICE: 320 ± 160 s versus HIIT: 198 ± 118 s) increased significantly (p<.001), with the groups differing significantly (p<.001). Time from IANS until TTE was prolonged significantly among the HIIT group (27 ± 66s, p=.030), while among the MICE group a significant reduction of time from IANS until TTE (59 ± 109s; p=.017) was determined. Between-group difference is significant (p=.003) for this parameter. In both groups TTE increased significantly (HIIT: 27.2 ± 17.7% versus MICE: 29.0 ± 19.4%, both p<.001) at a similar level (p=.279). Conclusion. HIIT and MICE protocols, when adjusted for total workload, similarly increased running performance in untrained male subjects; however, the underlying mechanisms differ fundamentally. Due to its effects on aerobic and anaerobic performance improvement, HIIT can be recommended for untrained individuals as a time-efficient alternative or complementary training method to MICE. However, our protocol did not confirm the general superiority of HIIT versus MICE on the key endurance parameter “time to exhaustion” that has been reported by other comparative exercise studies.

Edaphic properties as key drivers for woody species distributions in tropical savannic and forest habitats

2019 ◽  
Vol 67 (1) ◽  
pp. 70
Author(s):  
P. M. S. Rodrigues ◽  
J. O. Silva ◽  
C. E. G. R. Schaefer
Keyword(s):  
Plant Species ◽  
Species Distribution ◽  
Soil Texture ◽  
Woody Species ◽  
Nutrient Status ◽  
Significant Response ◽  
Unimodal Response ◽  
The Individual ◽  
Edaphic Gradients ◽  
Forest Habitats

Edaphic gradients can explain plant species distribution at a local scale in the neotropics and elsewhere, but few studies have evaluated the individual responses of species to such gradients. We collected data on species and soils in open savannic and forest formations (totalling five habitats in each formation), aiming to evaluate the importance of edaphic factors on the distribution of woody plant species in tropical habitats. Logistic regression was used to test the influence of predictor variables (soil texture and fertility) on plant occurrence (presence or absence). Most species (73%) responded to the edaphic gradients. However, the edaphic gradients did not explain the distribution of the remaining 27% of species, which implies the existence of other factors determining their occurrence. Soil fertility (nutritional status) was the major factor in forest habitats (65% of the species which showed significant response), while soil texture was the most explanatory factor for species occurrence in open habitats (55% of the species that showed a significant response). Thus, nutrient status was less limiting and soil texture was more limiting in savannic formations, whereas the opposite was observed for forest formations. Most species showing a relationship with edaphic gradients had a unimodal response, which is in accordance with the literature. Our study showed that soil properties largely regulate the distribution of plant species in tropical habitats, despite other factors not investigated here also having an effect on several of the studied species. Models of species distribution that take into account environmental heterogeneity are key for the elaboration of strategies for the conservation and restoration of ecosystems.

scholarly journals EFFICIENT METHOD OF DNA ISOLATION FROM BULKING SAMPLES OF SEEDLINGS

2021 ◽  
Vol 2021 (3) ◽  
pp. 29-48
Author(s):  
Irina Klimenko ◽  
Alexey Antonov ◽  
Vladimir Dushkin ◽  
Anastasia Shamustakimova ◽  
Yulian Mavlyutov
Keyword(s):  
Dna Isolation ◽  
Low Cost ◽  
Leaf Tissue ◽  
Perennial Grasses ◽  
Genetic Studies ◽  
Modified Method ◽  
Extraction Buffer ◽  
Low Efficiency ◽  
Commercial Kits ◽  
The Individual

Forage annual and perennial grasses are the difficult subject for molecular and genetic studies because of the problem with obtaining qualitative genomic DNA for PCR, due of high content of proteins, polysaccharides and polyphenols. The known methods of DNA extraction or the numerous commercial kits allow isolating purified nucleic acids from the leaf tissue, but characterized by low efficiency at seedlings using. The modified method of DNA isolation, based on the SDS-extraction buffer (sodium dodecil sulfate), is presented in this study. Significant modifications were introduced in the reagents compound and the steps of procedure accordingly to used type of plant tissue and the result was positive at usage on the bulking samples, as well as on the individual genotypes (the only seedling). Reliability of this method and the functionality of the obtained DNA samples were tested in PCR with different molecular markers (SSR, SRAP and PawS) in researches on revealing of forage legume grasses DNA polymorphism. The general advantages of the proposed method are simplicity and effectiveness, the possibility to isolate qualitative DNA without toxic reagents application, as well as relatively low cost and availability of reagents. This method can be useful for studying the genetic biodiversity and for decision the different tasks, required the rapid analysis of large plant populations.

scholarly journals Floristic patterns of the neotropical forests, savannas and scrublands with Trithrinax campestris (Arecaceae) in central Argentina

2021 ◽  
Vol 2 ◽  
pp. 5-18
Author(s):  
Sebastián R. Zeballos ◽  
Marcelo R. Cabido ◽  
Juan J. Cantero ◽  
Alicia T.R. Acosta ◽  
M. Virginia Palchetti ◽  
...  
Keyword(s):  
Vascular Plant ◽  
Floristic Composition ◽  
Fire Frequency ◽  
Vegetation Types ◽  
Neotropical Forests ◽  
Central Argentina ◽  
Partitioning Around Medoids ◽  
Wide Range ◽  
Palm Species ◽  
Floristic Data

Aims: Trithrinax campestris is one of the palm species with the southernmost distribution in the Neotropics. Despite that the vegetation types in which T. campestris occurs are nowadays heavily threatened by land use and land cover changes, their floristic composition and structure are still to be documented. In order to characterize T. campestris habitats, the aim of this study was to describe the floristic composition of the vegetation types in which this palm occurs and their relationships with different environmental factors. Study area: The survey was conducted in central Argentina in an area comprising the southern extreme of the distribution of T. campestris in the following phytogeographic areas: Espinal, Lowland and Mountain Chaco. Methods: Following the Braun-Blanquet approach we collected 92 floristic relevés recording a total of 601 vascular plant species. Vegetation was classified through the ISOPAM hierarchical analysis. Bioclimatic and elevation data were related to the floristic data through the ISOMAP ordination. Remote-sensed images (Landsat TM, ETM+ and OLI) were used to characterize the fire frequency in the 92 stands. Results: Four vegetation types that differed in floristic composition and in diagnostic species were discriminated: 1.1 Celtis tala/Sida rhombifolia closed forest; 1.2 Aspidosperma quebracho-blanco/Prosopis kuntzei open forest; 2.1 Jarava pseudoichu/Vachellia caven open savanna; and 2.2 Acalypha variabilis/Nassella cordobensis scrubland. The ISOMAP ordination showed that differences in floristic composition were related to elevation, topography and climatic variables.Out of the 92 stands, only 21 showed the occurrence of fires during the period 1999–2018. Conclusions: Our results evidenced that vegetation types (forests, savannas and scrublands) comprising T. campestris developed in a wide range of environmental conditions. This is the first study that focuses on all vegetation types in which T. campestris occurs in central Argentina and it is relevant for conservation and sustainable management of the only native palm species in the flora of this part of the country. Taxonomic reference: Catálogo de las Plantas Vasculares del Cono Sur (Zuloaga et al. 2008) and its online update (http://www.darwin.edu.ar). Abbreviations: ISOMAP = isometric feature mapping; ISOPAM = isometric partitioning around medoids.

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