The influence of plant diversity on the resilience of harvester termites to fire

1995 ◽  
Vol 2 (3) ◽  
pp. 279 ◽  
Author(s):  
Max Abensperg-Traun ◽  
Dion Steven ◽  
Lyn Atkins
Keyword(s):  
Western Australia ◽  
High Intensity ◽  
Experimental Studies ◽  
Grazing Pressure ◽  
Livestock Grazing ◽  
Floristic Diversity ◽  
Long Term Effects ◽  
Burnt Area ◽  
Food Species

The harvester termites in floristically rich mallee-heath of southern Western Australia appear resilient to high-intensity fire. This contrasts with the temporary extinction of harvesters occupying a narrow food niche in floristically simple, intensely burnt spinifex Triodia angusta grassland in tropical Western Australia. The present study examines the effects of high-intensity fire on harvester termites Drepanotermes tamminensis in vegetation of intermediate floristic diversity and compares its findings with these earlier studies. We sampled 20 mounds (termitaria) in both an unburnt and (adjacent) burnt stand of Allocasuarina campestris shrubland. Although partially regenerated three years after the fire, 40% of mounds in the burnt area were abandoned, contrasting with 10% in the unburnt stand. No harvested chaff was found in any of the abandoned mounds. The extent of mound occupation by D. tamminensis was considerably lower, and ant invasion higher, in the burnt stand. These findings are consistent with the hypothesis that high floristic diversity enhances the resilience of harvester termites to fire. The most likely mechanism is the availability of a range of plant (food) species with different regenerative responses to high-intensity fire. The death of spinifex and the associated harvester termites after fire may be atypical. We argue, however, that temporary extinction of harvester populations in arid Australia may not be exceptional, particularly where fire coincides with drought and high livestock grazing pressure. Rigorous experimental studies are necessary to enhance our understanding of the long-term effects of fire on harvester termite populations in different vegetation types and climatic zones.

Experimental studies on the long-term effects of methylphenidate hydrochloride

Toxicology ◽  
1995 ◽  
Vol 103 (2) ◽  
pp. 77-84 ◽  
Author(s):  
June K. Dunnick ◽  
James R. Hailey
Keyword(s):  
Experimental Studies ◽  
Long Term Effects

scholarly journals Early Life Exposure to Fructose and Offspring Phenotype: Implications for Long Term Metabolic Homeostasis

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Deborah M. Sloboda ◽  
Minglan Li ◽  
Rachna Patel ◽  
Zoe E. Clayton ◽  
Cassandra Yap ◽  
...  
Keyword(s):  
Maternal Obesity ◽  
Experimental Studies ◽  
Long Term Effects ◽  
Obesity Epidemic ◽  
Fructose Intake ◽  
The Metabolic Syndrome ◽  
Early Life Exposure ◽  
High Fructose ◽  
Rising Incidence

The consumption of artificially sweetened processed foods, particularly high in fructose or high fructose corn syrup, has increased significantly in the past few decades. As such, interest into the long term outcomes of consuming high levels of fructose has increased significantly, particularly when the exposure is early in life. Epidemiological and experimental evidence has linked fructose consumption to the metabolic syndrome and associated comorbidities—implicating fructose as a potential factor in the obesity epidemic. Yet, despite the widespread consumption of fructose-containing foods and beverages and the rising incidence of maternal obesity, little attention has been paid to the possible adverse effects of maternal fructose consumption on the developing fetus and long term effects on offspring. In this paper we review studies investigating the effects of fructose intake on metabolic outcomes in both mother and offspring using human and experimental studies.

scholarly journals Correlation between Heart Rate Variability and Claustrum Stimulation – Hypothesis, Experimental Studies and Future Perspectives

2021 ◽  
Vol 31 (3) ◽  
pp. 529-536
Author(s):  
Bogdan PAVEL ◽  
◽  
Mihaela Roxana POPESCU ◽  
Carmen-Denise-Mihaela ZAHIU ◽  
Patricia Demetria POPOVICI ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Experimental Studies ◽  
Insular Cortex ◽  
Long Term Effects ◽  
Cardiovascular Prognosis ◽  
External Capsule ◽  
Motor Effects ◽  
The Brain

Heart rate variability (HRV) has long been associated with cardiovascular risk, especially after a myocardial infarction, but also in general. HRV refl ects and is used as a surrogate for the balance between sympathetic and parasympathetic systems in modulating the cardiovascular activity. A low HRV, traditionally associated to sympathovagal imbalance, is associated with a worse cardiovascular prognosis. Deep brain stimulation (DBS) is a surgical technique used for severe cases of Parkinson’s disease and other neurologic pathologies. DBS is performed in various areas of the brain and through different protocols. The claustrum, an area located between the external capsule and the insular cortex, was recently shown to be connected to Parkinson’s motor symptoms. As DBS in other regions of the brain has proven non-motor effects, like infl uencing the HRV, we sought to document the effect of claustrum stimulation on the sympatho-vagal balance (SVB). Our preliminary data indicates that claustrum stimulation inclines the SVB toward the latter, but more studies are required to observe the long-term effects of this type of stimulation.

Response of birds to a wildfire in the Great Western Woodlands, Western Australia.

2013 ◽  
Vol 19 (4) ◽  
pp. 188 ◽  
Author(s):  
Harry F Recher ◽  
William E Davis Jr
Keyword(s):  
Western Australia ◽  
Fire Frequency ◽  
First Year ◽  
Large Area ◽  
Burnt Area ◽  
Open Country ◽  
Second Year ◽  
Eucalypt Woodland ◽  
Number Of Individuals

In December 2005, a wildfire burnt a large area of semi-arid eucalypt woodland along ~10 km of the Norseman- Coolgardie Road north of Norseman in the Great Western Woodlands (GWW), Western Australia. Few birds used the burnt area in the first year after the fire and these were mainly ground and shrub foraging insectivores. There was no influx of seed-eaters or open-country species as reported for post-fire habitats elsewhere in southern Australia. The greatest number of individuals and species of birds occurred in the second year post-fire when ground and shrub vegetation was floristically most diverse. Canopy foragers were attracted to the burnt area in the second year by an outbreak of psyllid insects on seedling eucalypts. At the same time, bark dwelling arthropods associated with the standing stems of fire-killed eucalypts attracted bark-foragers. From the third year, small insectivorous ground, shrub, and canopy foragers dominated the avifauna on the burnt area. These foraged on fire-killed shrubs, as well as living vegetation, including the lignotuberous regrowth of eucalypts. Bark foragers were uncommon after the second year. Throughout the study, the burnt area had fewer species and individuals than adjacent unburnt habitats. Compared with unburnt woodlands there were few differences in how species foraged on the burnt plots, but most species foraged lower reflecting the stature of the vegetation in the burnt woodland. Nectar-feeders, fruit-eaters, large insectivores, raptors, and parrots, although common in the unburnt woodland, were absent or rare in the burnt area. This reflected the limited regrowth of vegetation on the burnt area, which lacked the structural and floristic complexity of nearby unburnt woodlands. Ground foragers probably commenced nesting on the burnt area in the first year, with shrub and canopy foragers nesting from the second year. However, after five years, there was no evidence of large insectivores, nectar-feeders, raptors, seed-eaters, or foliage-eaters (i.e., parrots) nesting despite their abundance in adjacent unburnt woodland. Some of the unburnt woodlands monitored in this study were even-aged regeneration estimated to be 30–50 years post-fire or logging. Regardless of origin, these even-aged plots lacked the diverse avifauna associated with mature woodlands and suggest that post-fire recovery of birds and vegetation in these woodlands is likely to take decades and probably more than 100 years. If so, human activities that increase fire frequency in the GWW, including climate change and fuel-reduction burns, will have long-term adverse impacts on regional biodiversity exceeding those associated with wildfires in less arid forests and woodlands where rates of recovery are more rapid.

Long-term effects of high-intensity exercise training in patients with COPD: a controlled study

2019 ◽  
Author(s):  
Tobias Boeselt ◽  
Christoph Nell ◽  
Lea Lütteken ◽  
Martina Veith ◽  
Bjoern Beutel ◽  
...  
Keyword(s):  
Exercise Training ◽  
High Intensity ◽  
High Intensity Exercise ◽  
Controlled Study ◽  
Long Term Effects

Higher filtration fraction in formerly early-onset preeclamptic women without comorbidity

2015 ◽  
Vol 308 (8) ◽  
pp. F824-F831 ◽  
Author(s):  
Tsjitske J. Toering ◽  
Anne Marijn van der Graaf ◽  
Folkert W. Visser ◽  
Henk Groen ◽  
Marijke M. Faas ◽  
...  
Keyword(s):  
Early Onset ◽  
Experimental Studies ◽  
Estimating Equation ◽  
Renal Hemodynamics ◽  
Ang Ii ◽  
Long Term Effects ◽  
Filtration Fraction ◽  
Increased Risk ◽  
Stage Renal Disease

Formerly preeclamptic women have an increased risk for developing end-stage renal disease, which has been attributed to altered renal hemodynamics and abnormalities in the renin-angiotensin-aldosterone system. Whether this is due to preeclampsia itself or to comorbid conditions is unknown. Renal hemodynamics and responsiveness to ANG II during low Na+ intake (7 days, 50 mmol Na+/24 h) and high Na+ (HS) intake (7 days, 200 mmol Na+/24 h) were studied in 18 healthy normotensive formerly early-onset preeclamptic women (fPE women) and 18 healthy control subjects (fHP women), all selected for absence of comorbidity. At the end of each diet, renal hemodynamics and blood pressure were measured before and during graded ANG II infusion. Both HS intake and former preeclampsia increased filtration fraction (FF) without an interaction between the two. FF was highest during HS intake in fPE women [0.31 ± 0.12 vs. 0.29 ± 0.11 in fHP women, generalized estimating equation analysis (body mass index corrected), P = 0.03]. The renal response to ANG II infusion was not different between groups. In conclusion, fPE women have a higher FF compared with fHP women. As this was observed in the absence of comorbidity, preeclampsia itself might exert long-term effects on renal hemodynamics. However, we cannot exclude the presence of prepregnancy alterations in renal function, which, in itself, lead to an increased risk for preeclampsia. In experimental studies, an elevated FF has been shown to play a pathogenic role in the development of hypertension and renal damage. Future studies, however, should evaluate whether the subtle differences in renal hemodynamics after preeclampsia contribute to the increased long-term renal risk after preeclampsia.

scholarly journals Response of endemic afroalpine rodents to the removal of livestock grazing pressure

2011 ◽  
Vol 57 (6) ◽  
pp. 741-750 ◽  
Author(s):  
Flavie Vial ◽  
David W. Macdonald ◽  
Daniel T. Haydon
Keyword(s):  
Grazing Pressure ◽  
Livestock Grazing ◽  
Experimental Investigations ◽  
Close Monitoring ◽  
Apparent Lack ◽  
Mole Rat ◽  
Domestic Livestock ◽  
Animal Communities ◽  
Rodent Populations

Abstract The Bale Mountains of Ethiopia represent the world’s largest continuous extent of afroalpine habitat. With a peak combined density of over 8000 individuals/km2, the endemic giant mole rat Tachyoryctes macrocephalus, Blick’s grass rat Arvicanthis blicki and the brush-furred mouse Lophuromys melanonyx are the dominant wild herbivores within this ecosystem and may be affected by the presence of high densities of domestic livestock. The purpose of this study was to establish whether these endemic rodent populations could respond to the removal of grazing pressure inside three 0.25 hectare livestock exclosures (paired with grazed control plots) and to determine whether such response was mediated through concomitant changes in the vegetation structure. We hypothesised that livestock grazing negatively affects endemic rodent populations through competition or increased predation risk and we predicted an increase in rodent biomass following the removal of grazing pressure. We found no evidence of rodent populations responding to the removal of livestock after fourteen months. The short-term nature of the experimental design, environmental fluctuations and the ecosystem’s inherent stochasticity may explain the apparent lack of a significant response. However, while this study is inconclusive, it emphasises the need for more long-term experimental investigations to assess the effects of domestic grazers on vegetation and on dependent communities. The effects of rapidly increasing livestock numbers in the Bale Mountains will require continued close monitoring of vegetation and endemic animal communities as the afroalpine is altered by external biotic and abiotic forces.

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