scholarly journals Long-term fire resilience of the Ericaceous Belt, Bale Mountains, Ethiopia

2019 ◽  
Vol 15 (7) ◽  
pp. 20190357 ◽  
Author(s):  
Graciela Gil-Romera ◽  
Carole Adolf ◽  
Blas M. Benito ◽  
Lucas Bittner ◽  
Maria U. Johansson ◽  
...  
Keyword(s):  
Fire History ◽  
Time Perspective ◽  
Negative Impact ◽  
Current Knowledge ◽  
Landscape Management ◽  
Fire Occurrence ◽  
Controlled Burning ◽  
History Of ◽  
Grazing Systems

Fire is the most frequent disturbance in the Ericaceous Belt ( ca 3000–4300 m.a.s.l.), one of the most important plant communities of tropical African mountains. Through resprouting after fire, Erica establishes a positive fire feedback under certain burning regimes. However, present-day human activity in the Bale Mountains of Ethiopia includes fire and grazing systems that may have a negative impact on the resilience of the ericaceous ecosystem. Current knowledge of Erica –fire relationships is based on studies of modern vegetation, lacking a longer time perspective that can shed light on baseline conditions for the fire feedback. We hypothesize that fire has influenced Erica communities in the Bale Mountains at millennial time-scales. To test this, we (1) identify the fire history of the Bale Mountains through a pollen and charcoal record from Garba Guracha, a lake at 3950 m.a.s.l., and (2) describe the long-term bidirectional feedback between wildfire and Erica, which may control the ecosystem's resilience. Our results support fire occurrence in the area since ca 14 000 years ago, with particularly intense burning during the early Holocene, 10.8–6.0 cal ka BP. We show that a positive feedback between Erica abundance and fire occurrence was in operation throughout the Lateglacial and Holocene, and interpret the Ericaceous Belt of the Ethiopian mountains as a long-term fire resilient ecosystem. We propose that controlled burning should be an integral part of landscape management in the Bale Mountains National Park.

scholarly journals Fire Exclusion Destroys Habitats for At-Risk Species in a British Columbia Protected Area

Fire ◽  
2019 ◽  
Vol 2 (3) ◽  
pp. 48
Author(s):  
Kira M. Hoffman ◽  
Sara B. Wickham ◽  
William S. McInnes ◽  
Brian M. Starzomski
Keyword(s):  
British Columbia ◽  
Fire History ◽  
Prescribed Burning ◽  
Douglas Fir ◽  
Conifer Encroachment ◽  
Oak Trees ◽  
Composition And Structure ◽  
Fire Exclusion ◽  
History Of

Fire exclusion and suppression has altered the composition and structure of Garry oak and associated ecosystems in British Columbia. The absence of frequent low severity ground fires has been one of the main contributors to dense patches of non-native grasses, shrubs, and encroaching Douglas-fir trees in historical Garry oak dominated meadows. This case study uses remote sensing and dendrochronology to reconstruct the stand dynamics and long-term fire history of a Garry oak meadow situated within Helliwell Provincial Park located on Hornby Island, British Columbia. The Garry oak habitat in Helliwell Park has decreased by 50% since 1950 due to conifer encroachment. Lower densities and mortalities of Garry oak trees were associated with the presence of overstory Douglas-fir trees. To slow conifer encroachment into the remaining Garry oak meadows, we recommend that mechanical thinning of Douglas-fir be followed by a prescribed burning program. Reintroducing fire to Garry oak ecosystems can restore and maintain populations of plants, mammals, and insects that rely on these fire resilient habitats.

scholarly journals Insights into the evolution of social systems and species from baboon studies

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Julia Fischer ◽  
James P Higham ◽  
Susan C Alberts ◽  
Louise Barrett ◽  
Jacinta C Beehner ◽  
...  
Keyword(s):  
Current Knowledge ◽  
Social Systems ◽  
Population Expansion ◽  
Sub Saharan Africa ◽  
Future Research ◽  
Closely Related Species ◽  
Ecological Flexibility ◽  
History Of ◽  
Sub Saharan

Baboons, members of the genus Papio, comprise six closely related species distributed throughout sub-Saharan Africa and southwest Arabia. The species exhibit more ecological flexibility and a wider range of social systems than many other primates. This article summarizes our current knowledge of the natural history of baboons and highlights directions for future research. We suggest that baboons can serve as a valuable model for complex evolutionary processes, such as speciation and hybridization. The evolution of baboons has been heavily shaped by climatic changes and population expansion and fragmentation in the African savanna environment, similar to the processes that acted during human evolution. With accumulating long-term data, and new data from previously understudied species, baboons are ideally suited for investigating the links between sociality, health, longevity and reproductive success. To achieve these aims, we propose a closer integration of studies at the proximate level, including functional genomics, with behavioral and ecological studies.

Long-term relations among fire, fuel, and climate in the north-western US based on lake-sediment studies

2008 ◽  
Vol 17 (1) ◽  
pp. 72 ◽  
Author(s):  
Cathy Whitlock ◽  
Jennifer Marlon ◽  
Christy Briles ◽  
Andrea Brunelle ◽  
Colin Long ◽  
...  
Keyword(s):  
Fire History ◽  
Spatial Scales ◽  
Fire Regimes ◽  
Early Holocene ◽  
Summer Drought ◽  
Fire Occurrence ◽  
The North ◽  
Episode Frequency ◽  
North Western

Pollen and high-resolution charcoal records from the north-western USA provide an opportunity to examine the linkages among fire, climate, and fuels on multiple temporal and spatial scales. The data suggest that general charcoal levels were low in the late-glacial period and increased steadily through the last 11 000 years with increasing fuel biomass. At local scales, fire occurrence is governed by the interaction of site controls, including vegetation, local climate and fire weather, and topography. At subregional scales, patterns in the long term fire-episode frequency data are apparent: The Coast Range had relatively few fires in the Holocene, whereas the Klamath–Siskiyou region experienced frequent fire episodes. Fire regimes in the northern Rocky Mountains have been strongly governed by millennial- and centennial-scale climate variability and regional differences in summer moisture. At regional scales, sites in present-day summer-dry areas show a period of protracted high fire activity within the early Holocene that is attributed to intensified summer drought in the summer-dry region. Sites in summer-wet areas show the opposite pattern, that fire was lower in frequency than present in the early Holocene as result of strengthened monsoonal circulation then. Higher fire-episode frequency at many sites in the last 2000 years is attributed to greater drought during the Medieval Climate Anomaly and possibly anthropogenic burning. The association between drought, increased fire occurrence, and available fuels evident on several time scales suggests that long-term fire history patterns should be considered in current assessments of historical fire regimes and fuel conditions.

Fire history and the establishment of oaks and maples in second-growth forests

2008 ◽  
Vol 38 (5) ◽  
pp. 1184-1198 ◽  
Author(s):  
Todd F. Hutchinson ◽  
Robert P. Long ◽  
Robert D. Ford ◽  
Elaine Kennedy Sutherland
Keyword(s):  
Cross Sections ◽  
Fire History ◽  
Direct Relationship ◽  
Fire Occurrence ◽  
Fire Control ◽  
Second Growth ◽  
History Of ◽  
Stand Thinning ◽  
Large Pulse ◽  
Cut Stumps

We used dendrochronology to examine the influence of past fires on oak and maple establishment. Six study units were located in southern Ohio, where organized fire control began in 1923. After stand thinning in 2000, we collected basal cross sections from cut stumps of oak (n = 137) and maple (n = 204). The fire history of each unit was developed from the oaks, and both oak and maple establishment were examined in relation to fire history. Twenty-six fires were documented from 1870 to1933; thereafter, only two fires were identified. Weibull median fire-return intervals ranged from 9.1 to 11.3 years for the period ending 1935; mean fire occurrence probabilities (years/fires) for the same period ranged from 11.6 to 30.7 years. Among units, stand initiation began ca. 1845 to 1900, and virtually no oak recruitment was recorded after 1925. Most maples established after the cessation of fires. In several units, the last significant fire was followed immediately by a large pulse of maple establishment and the cessation of oak recruitment, indicating a direct relationship between fire cessation and a shift from oak to maple establishment.

Fires in temperate peatlands (southern Quebec): past and recent trends

2007 ◽  
Vol 85 (3) ◽  
pp. 263-272 ◽  
Author(s):  
Claude Lavoie ◽  
Stéphanie Pellerin
Keyword(s):  
Fire History ◽  
Fire Regime ◽  
Fire Frequency ◽  
Time Interval ◽  
Temperate Region ◽  
Forest Expansion ◽  
Short Period ◽  
History Of ◽  
Recent Trends

In this study, we reconstructed the long-term fire history of a set of ombrotrophic peatlands (bogs) located in a temperate region of southern Quebec (Bas-Saint-Laurent). Past and recent fire-free intervals (time interval between two consecutive fires) were compared using macrofossil analyses. During most of the Holocene epoch, fires were relatively rare events in bogs of the Bas-Saint-Laurent region. The fire-free intervals were approximately ten times longer (all sites considered) before the beginning of agricultural activities in the region (1800 AD) than after. This strongly suggests an anthropogenic influence on the fire regime prevailing in the bogs over the last 200 years. However, the shortening of the fire-free intervals was mainly the result of the ignition of one or two fires in almost every site during a relatively short period (200 years), rather than a higher fire frequency in each of the bogs. In some cases, fires had an influence on the vegetation structure of bogs, but it is more likely that a combination of several disturbances (fire, drainage, and drier than average summers) favoured the establishment of dense stands of pine and spruce, a forest expansion phenomenon that is now widespread in temperate bogs.

Solar photovoltaic applications: opportunities and challenges

2018 ◽  
Vol 34 (4) ◽  
pp. 503-528 ◽  
Author(s):  
Farihahusnah Hussin ◽  
Gulnaziya Issabayeva ◽  
Mohamed Kheireddine Aroua
Keyword(s):  
Fossil Fuels ◽  
Negative Impact ◽  
Photovoltaic Systems ◽  
Solar Photovoltaic ◽  
Water And Wastewater Treatment ◽  
History Of ◽  
Photovoltaic Technologies ◽  
Current Energy

Abstract The heavy reliance on fossil fuels, given their inevitable depletion and serious negative impact on the environment, has led to intensive scientific research to produce solutions which will ensure sustainable supply of energy based on renewable sources. Solar radiation is one of the major sources of clean and renewable energy with the potential to provide ample power for the growing human population in the long term. The current energy crisis is aggravated by the escalating concerns over the water quality especially in developing countries. There is great potential for utilisation of solar energy through solar photovoltaic systems throughout the world for electricity generation as well as water and wastewater treatment. Innovations in this area have opened new prospects to improve the quality of life for people as a whole. Hence, the focus of this review paper is to provide the reader with a brief history of solar photovoltaic systems, the various types of solar photovoltaic materials available and the solar cell efficiencies attained with the current solar photovoltaic technologies. Furthermore, applications of photovoltaic systems are discussed in terms of their societal economic and environmental effects.

Hyperinsulinism hyperammonaemia (HI/HA) syndrome due to GLUD1 mutation: phenotypic variations ranging from late presentation to spontaneous resolution

2020 ◽  
Vol 33 (5) ◽  
pp. 675-679
Author(s):  
Agnieszka Brandt ◽  
Neha Agarwal ◽  
Dinesh Giri ◽  
Zoe Yung ◽  
Mohammad Didi ◽  
...  
Keyword(s):  
Current Knowledge ◽  
Ammonia Level ◽  
Late Presentation ◽  
Spontaneous Resolution ◽  
Delayed Presentation ◽  
Hyperinsulinaemic Hypoglycaemia ◽  
Activating Mutations ◽  
Good Glycaemic Control ◽  
History Of

AbstractBackgroundThe hyperinsulinism/hyperammonaemia (HI/HA) syndrome is the second most common cause of hyperinsulinaemic hypoglycaemia, caused by activating mutations in GLUD1. In this article, we report a series of three unrelated patients with HI/HA syndrome who demonstrated variable phenotypes, ranging from delayed presentation to spontaneous resolution of hypoglycaemia, thereby expanding the current knowledge and understanding of GLUD1 mutations.Case presentationThis paper is a retrospective analysis of patients with HI/HA syndrome who demonstrated a variable disease course. Patient 1 presented with hypoglycaemic seizures at the age of 7 months and was diagnosed with HI/HA syndrome. Patient 2, a 5-year-old boy, on anti-convulsants since 8 months of age, was diagnosed with HI/HA at the age of 4 years. Patient 3, an 11-year-old girl with a history of transient neonatal hypoglycaemia, was diagnosed with HI/HA at the age of 12 months following evaluation for absence seizures. Patients 1 and 2 had raised ammonia levels, whilst patient 3 had normal ammonia level. The genetic analysis in all three patients confirmed GLUD1 mutation. Good glycaemic control was observed in all following diazoxide treatment. All patients have learning difficulties. Patient 1 demonstrated spontaneous resolution of hypoglycaemia at the age of 8 years, enabling discontinuation of diazoxide.ConclusionsThe cases highlight the diagnostic challenges in HI/HA syndrome due to a highly variable presentation. Knowledge of variable phenotypes would enable early diagnosis, thereby decreasing the risk of long-term neurological damage. Spontaneous resolution of hyperinsulinism could occur, and it is important to consider a trial off diazoxide therapy especially if the patients are on a small dose of diazoxide.

Reconstruction of the long-term fire history of an old-growth deciduous forest in Southern Québec, Canada, from charred wood in mineral soils

2005 ◽  
Vol 64 (1) ◽  
pp. 36-43 ◽  
Author(s):  
Brigitte Talon ◽  
Serge Payette ◽  
Louise Filion ◽  
Ann Delwaide
Keyword(s):  
Forest Fires ◽  
Sugar Maple ◽  
Fire History ◽  
Deciduous Forest ◽  
Old Growth ◽  
History Of ◽  
Mineral Soils ◽  
Tree Uprooting ◽  
Conifer Trees

AbstractCharcoal particles are widespread in terrestrial and lake environments of the northern temperate and boreal biomes where they are used to reconstruct past fire events and regimes. In this study, we used botanically identified and radiocarbon-dated charcoal macrofossils in mineral soils as a paleoecological tool to reconstruct past fire activity at the stand scale. Charcoal macrofossils buried in podzolic soils by tree uprooting were analyzed to reconstruct the long-term fire history of an old-growth deciduous forest in southern Québec. Charcoal fragments were sampled from the uppermost mineral soil horizons and identified based on anatomical characters. Spruce (Picea spp.) fragments dominated the charcoal assemblage, along with relatively abundant wood fragments of sugar maple (Acer saccharum) and birch (Betula spp.), and rare fragments of pine (Pinus cf. strobus) and white cedar (Thuja canadensis). AMS radiocarbon dates from 16 charcoal fragments indicated that forest fires were widespread during the early Holocene, whereas no fires were recorded from the mid-Holocene to present. The paucity of charcoal data during this period, however, does not preclude that a fire event of lower severity may have occurred. At least eight forest fires occurred at the study site between 10,400 and 6300 cal yr B.P., with a dominance of burned conifer trees between 10,400 and 9000 cal yr B.P. and burned conifer and deciduous trees between 9000 and 6300 cal yr B.P. Based on the charcoal record, the climate at the study site was relatively dry during the early Holocene, and more humid from 6300 cal yr B.P. to present. However, it is also possible that the predominance of conifer trees in the charcoal record between 10,400 and 6300 cal yr B.P. created propitious conditions for fire spreading. The charcoal record supports inferences based on pollen influx data (Labelle, C., Richard, P.J.H. 1981. Végétation tardiglaciaire et postglaciaire au sud-est du Parc des Laurentides, Québec. Géographie Physique et Quaternaire 35, 345-359) of the early arrival of spruce and sugar maple in the study area shortly after deglaciation. We conclude that macroscopic charcoal analysis of mineral soils subjected to disturbance by tree uprooting may be a useful paleoecological tool to reconstruct long-term forest fire history at the stand scale.

scholarly journals Long-term fire history of maple (Acer) forest sites in the central St. Lawrence Lowland, Quebec

2016 ◽  
Vol 46 (6) ◽  
pp. 822-831 ◽  
Author(s):  
Serge Payette ◽  
Vanessa Pilon ◽  
Pierre-Luc Couillard ◽  
Mathieu Frégeau
Keyword(s):  
Sugar Maple ◽  
Fire History ◽  
Mixed Forest ◽  
Acer Rubrum ◽  
Quebec City ◽  
Red Maple ◽  
Conifer Forest ◽  
Disturbance Factor ◽  
History Of

In the St-Lawrence lowlands, sugar maple (Acer saccharum Marsh.) is considered the dominant species of old-growth deciduous forests, whereas red maple (Acer rubrum L.) tends to dominate sites recently disturbed by logging and agricultural practices. Considering that the long-term influence of fire is not documented for such stands, we reconstructed the postglacial tree composition (as deduced from charcoal species) and fire history of a sugar maple stand (Ste-Françoise area) and a red maple stand (Villeroy area) located southwest of Québec City, Canada. The sites are 10 km apart and show contrasting soil and landform features. Using botanical identification and 14C dating of soil macrocharcoal, we found that fire struck both maple stands 14–20 times since deglaciation. Most fires occurred in the early Holocene and during the last 2000 years, with the mid Holocene being a period with low fire frequency or no fires. During the last 1600 years, the Villeroy stand shifted from a Tsuga canadensis (L.) Carrière – conifer forest to a mixed forest and, most recently, to a red maple stand as fire became more frequent, possibly due to human activities of the last 400 years. This study confirms the influence of fire on the development of maple forests. Fire should be considered as an important disturbance factor in the dynamics of temperate deciduous and mixed forests.

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