Biennial Spring Research Articles

The population dynamics of four grass species in relation to burning in the KwaZulu-Natal Drakensberg

Marked tillers of Heteropogon contortus, Trachypogon spicatus, Tristachya leucothrix and Harpochloa falx were sampled regularly over a two-year period in Highland Sourveld burnt annually in winter and biennially in spring. Parameters recorded were height of shoot apex, tiller mass, number of new lateral tillers and time of flowering. Monitoring of marked tillers before and after each burn enabled the life history of populations of tillers to be followed. In all species investigated, flowering was found to be of minimal importance with most tillers remaining vegetative until death. Shoot apices remained close to the soil surface (<20 mm) enabling them to survive frequent burns. All species exhibited smooth survivorship curves, suggesting that dramatic fluctuations in climate and severe defoliation, as by fire, had little impact on mortality. The differential response of the four grass species was explained by their different reproductive capacities and reproductive rates. The predicted responses to fire regime were verified by changes that took place at the study area from 1981 to 2019, showing the importance of applying appropriate burning regimes to maintain the bud bank. A biennial spring burn was best for maintaining these important grass species at current levels of abundance in the KwaZulu-Natal Drakensberg.

How stable is the tuft structure of a mesic Drakensberg grassland under various burning regimes?

Management options to maintain the stability of Drakensberg grasslands need to incorporate their dynamic nature in response to fire. This study addressed the lack of information on the spatial and temporal changes of these grasslands at a small (tuft) scale. The basal area of every tuft in three 0.25 m2 quadrats per replicate (3) of four burning treatments was mapped over two years in a long-term burning trial using a pantograph. The extent of change in size and shape of tufts indicated the dynamic nature of these grasslands from year to year. Basal cover of Themeda triandra was high in the annual winter (62.5%) and biennial spring (50.5%) burns, lower in the five-year burn (36.1%) and low in the biennial summer burn (11.5%). The bare area in the biennial summer burn increased by 5.6%, remained the same in the annual winter, and decreased in the biennial spring (6.1%) and five-year (7.8%) burns. The disappearance of Stiburus alopecuroides from the summer burn and increase in basal cover of Tristachya leucothrix indicates a directional change in composition that is likely to be irreversible. The biennial spring burn, where the three dominant species were in a state of equilibrium, is recommended for stability.

Natural Canopy Damage and the Ecological Restoration of Fire-Indicative Groundcover Vegetation in an Oak-Pine Forest

An important goal of restoring fire to upland oak-dominated communities that have experienced fire exclusion is restoring groundcover plant species diversity and composition indicative of fire-maintained habitats. Several studies have shown that fire alone, however, may not be sufficient to accomplish this goal. Furthermore, treatment-driven declines in rare forest specialists could negate the benefits of ecological restoration in these ecosystems. I present the results of an experiment examining effects of tornado-generated canopy openings and biennial spring burning on groundcover vegetation at an oak-pine forest in north Mississippi, USA. Results from four years of monitoring showed that species richness and abundance of species indicative of fire-maintained open habitats were greater at sites with canopy damage than at sites with undamaged canopies, especially in years without drought. Annual ruderals increased initially following canopy damage but then decreased. Few forest indicator species changed in abundance, and the few that did increased. Canopy openings appeared to have a greater effect than fire on groundcover vegetation, although some legumes and panicgrasses appeared to benefit directly from fire. Results suggest that fire restoration treatments must include both canopy openings and fire to effectively increase the diversity and distinctiveness of groundcover vegetation in mixed oak-pine forests. Prescribed burning after years of fire exclusion, by itself, does not constitute effective restoration of fire (at least in the short term), but it also does not appear to reduce the abundance of rare, forest-specialist groundcover species.

The long-term effects of fire regime on primary production of montane grasslands in South Africa

Natural grasslands deliver essential ecosystem services through plant production, which enhances water supply, nutrient cycling, soil retention and greenhouse gas mitigation. Although the condition of montane grasslands for provision of ecosystem services is maintained by regular annual or biennial burning, controversy exists over the impact of different frequencies and seasons of burning on grassland productivity. The objective of this study was to determine the long-term effects of different burning regimes on primary production and quality of the montane grasslands of the KwaZulu-Natal Drakensberg. There were no significant differences in the mean standing live mass between 30 years of annual winter and biennial spring burning. However, in unburnt areas productivity was 20% lower (118.2 g m−2) than in regularly burnt grassland (144.7–154.5 g m−2). Crude protein did not vary between the annual winter and biennial spring treatments (95–113 kg ha−1), but was significantly lower in unburned areas (45 kg ha−1). However, an infrequent fire in a protected area caused a temporary spike in crude protein (16%) compared with regular burning (5–10%), which can benefit wildlife. We conclude that montane grasslands can be burnt annually or biennially in the dormant season to promote long-term productivity.

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Australasian Journal of DermatologyVolume 52, Issue s2 p. 1-13 Biennial Spring Conference First published: 11 October 2011 https://doi.org/10.1111/j.1440-0960.2011.00810.xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Volume52, Issues2Special Issue: Abstracts presented at the Biennial Spring Conference, 13-16 October 2011, Hobart, Tasmania, AustraliaOctober 2011Pages 1-13 RelatedInformation

Author Index 2011

Australasian Journal of DermatologyVolume 52, Issue s2 p. 14-14 Author Index 2011 First published: 11 October 2011 https://doi.org/10.1111/j.1440-0960.2011.00811.xRead the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume52, Issues2Special Issue: Abstracts presented at the Biennial Spring Conference, 13‐16 October 2011, Hobart, Tasmania, AustraliaOctober 2011Pages 14-14 RelatedInformation

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Australasian Journal of DermatologyVolume 50, Issue s2 p. A47-A57 Free Access Biennial Spring Conference First published: 31 August 2009 https://doi.org/10.1111/j.1440-0960.2009.00551.xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Volume50, Issues2Special Issue: Abstracts of the Australasian College of Dermatologists Biennial Spring Conference, 8–11 October 2009, Hunter Valley, New South Wales, AustraliaOctober 2009Pages A47-A57 RelatedInformation

Biennial Spring Activity of Human Metapneumovirus in Austria

Human metapneumovirus (HMPV) is considered an important respiratory pathogen in young children. To gain insight into the seasonality and epidemiologic characteristics of HMPV infection, this study determined the frequency of HMPV infections in hospitalized infants during a 7-year period. By use of real-time reverse-transcriptase polymerase chain reaction, nasopharyngeal aspirates from 1612 infants less than 2 years of age who were hospitalized for acute respiratory tract illness were tested for the presence of HMPV. Weekly HMPV testing data were analyzed to assess the timing of HMPV activity. Season variability was estimated by comparing the onset, duration, peak, and end of outbreaks from October 2000 through October 2007. Overall, 109 (6.8%) of 1612 cases of acute respiratory illness were associated with HMPV infection. Seasonal HMPV activity varied substantially from year to year, both in prevalence rates of HMPV cases and in seasonal timing of outbreaks. HMPV activity was characterized by a biennial rhythm, with spring seasons occurring every second year, and these accounted for a substantial proportion, up to 30%, of hospitalized cases of acute respiratory tract illness. HMPV activity varies substantially from year to year, both in the frequency and timing of illness and shows a biennial pattern of alternating winter and spring activity.

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Soil Wind Erosion Hazard of Spring Wheat–Fallow as Affected by Long‐Term Climate and Tillage

We hypothesized that drought accelerates wind erosion by increasing plant and soil factors of erodibility together, compounding the erosion hazard. Erodibility factors measured in biennial spring wheat–fallow on Pachic and Typic Haploborolls soil were (i) soil‐inherent wind erodibility (SIWE) by rotary sieving, (ii) surface roughness by pin meter and chain methods, (iii) standing residue profile, and (iv) residue coverage photographically. Four tillage treatments ranged from low residue (LR) to no‐till (NT). The erodible fraction of surface soil (a SIWE measure) changed from 53% during a dry period (1989–1990) to a less erodible 26% during a wet period (1992–1994). Median erosion protection values calculated from flat and standing residue measurements made after seeding were, respectively, 16 and 43% in 1989 to 1990, and 80 and 76% in 1992 to 1994. Soil losses estimated by RWEQ model equations were 11 to 6100 times greater during 1989 to 1990, compared with 1992 to 1994. No‐till was protective, and estimated soil losses on LR were up to 3000 times greater than those on NT. However, low residue yields in 1988 (930 vs. 3640 kg/ha avg.) resulted in inadequate protection after seeding in 1990, even in NT; and soil losses in LR and NT were 13 and 8 Mg/ha, respectively. Results indicate biennial small grain–fallow is nonsustainable in the long term from a soil‐erosion perspective.

The dynamics ofThemeda Triandratillers in relation to burning in the natal Drakensberg

Abstract Marked tillers of Themeda triandra were sampled regularly over a two year period in Highland Sourveld burnt annually in winter, biennially in spring and after a single summer and early winter burning treatment. Parameters recorded were height of shoot apex, tiller mass, number of new lateral tillers and time of flowering. Monitoring of marked tillers before and after each burn enabled the life history of populations of tillers to be followed. There were no significant differences in survivorship between tillers in the annual winter and biennial spring burn treatments but winter burning stimulated the development of a greater number of daughters per parent. Both populations exhibited a constant death rate over the two year period. Only 8% of the marked T. triandra tillers survived the single summer burning treatment.

Soil Arthropod Response to Prairie Burning

Soil arthropod response to altered litter production in a Wisconsin prairie was examined after a long established biennial spring burning program was modified by substituting raking for burning in some experimental blocks, and substituting no disturbance for burning in others. Very few species were favored by increased surface litter in undisturbed blocks. After two biennial burnings or rakings, a drop in species numbers, density of individuals, and diversity of herbivore—decomposers occurred in undisturbed, and to a lesser extent, in raked blocks. Predatory soil arthropod species showed no response. These results suggest that soil detritus levels dropped slowly in response to decreased plant productivity in undisturbed blocks. The drop in soil arthropod community diversity which occurred in undisturbed blocks indicates a direct productivity—diversity relationship. Other field experiments show the same direct productivity—diversity relationship among consumers or terrestrial producers, but an inverse relationship among aquatic producers.