Morphological diversity and abundance of biological soil crusts differ in relation to landscape setting and vegetation type

2008 ◽  
Vol 56 (3) ◽  
pp. 246 ◽  
Author(s):  
A. Briggs ◽  
J. W. Morgan
Keyword(s):  
Vascular Plants ◽  
Vegetation Type ◽  
Biological Soil Crust ◽  
Biological Soil Crusts ◽  
Annual Rainfall ◽  
Soil Crust ◽  
Vegetation Types ◽  
Bare Ground ◽  
Soil Crusts ◽  
Morphological Composition

Biological soil crusts are common in many arid and semi-arid regions of the world, including Australia. Crusts alter soil factors including water availability, nutrient content and erosion susceptibility and are likely to both directly and indirectly affect vascular plants. Despite emerging recognition as important ecosystem components, these soil communities are understudied. We describe the morphological composition and distribution of lichens and bryophytes in soil crusts from the northern riverine plains, Victoria, in relation to landscape setting and vegetation type. Sampling was conducted across a geomorphological gradient in three different vegetation types (Callitris glaucophylla woodland, Eucalyptus woodland and red-soil native tussock grassland) with an annual rainfall of ~400 mm. Mean cover of biological soil crust for the study area was 18%, with mosses and crustose and foliose lichens the most conspicuous components. Total cover of biological soil crust increased as bare ground and vascular plant cover increased, and litter cover decreased. As a consequence, cover and morphological composition of biological soil crusts differed in the three vegetation types, with mosses responding differently from lichens and liverworts in relation to the cover of litter, bare ground and vascular plants. Hence, biological soil crusts were a conspicuous component in vegetation where they had not previously been described and may play an important role in regulating the structure and function of these plant communities.

Determinants of spatial variation in fire return period in a semiarid African savanna

2011 ◽  
Vol 20 (4) ◽  
pp. 540 ◽  
Author(s):  
T. G. O'Connor ◽  
C. M. Mulqueeny ◽  
P. S. Goodman
Keyword(s):  
Spatial Variation ◽  
Return Period ◽  
Vegetation Type ◽  
Fire Frequency ◽  
Fuel Load ◽  
Annual Rainfall ◽  
Vegetation Types ◽  
Terrestrial Vegetation ◽  
African Savanna ◽  
Data Set

Fire pattern is predicted to vary across an African savanna in accordance with spatial variation in rainfall through its effects on fuel production, vegetation type (on account of differences in fuel load and in flammability), and distribution of herbivores (because of their effects on fuel load). These predictions were examined for the 23 651-ha Mkuzi Game Reserve, KwaZulu-Natal, based on a 37-year data set. Fire return period varied from no occurrence to a fire every 1.76 years. Approximately 75% of the reserve experienced a fire approximately every 5 years, 25% every 4.1–2.2 years and less than 1% every 2 years on average. Fire return period decreased in relation to an increase in mean annual rainfall. For terrestrial vegetation types, median fire return periods decreased with increasing herbaceous biomass, from forest that did not burn to grasslands that burnt every 2.64 years. Fire was absent from some permanent wetlands but seasonal wetlands burnt every 5.29 years. Grazer biomass above 0.5 animal units ha–1 had a limiting influence on the maximum fire frequency of fire-prone vegetation types. The primary determinant of long-term spatial fire patterns is thus fuel load as determined by mean rainfall, vegetation type, and the effects of grazing herbivores.

scholarly journals Emission of nitrous acid from soil and biological soil crusts represents an important source of HONO in the remote atmosphere in Cyprus

2018 ◽  
Vol 18 (2) ◽  
pp. 799-813 ◽  
Author(s):  
Hannah Meusel ◽  
Alexandra Tamm ◽  
Uwe Kuhn ◽  
Dianming Wu ◽  
Anna Lena Leifke ◽  
...  
Keyword(s):  
Nitrous Acid ◽  
Biological Soil Crust ◽  
Ground Surface ◽  
Field Studies ◽  
Bare Soil ◽  
Biological Soil Crusts ◽  
Soil Crusts ◽  
Wide Range ◽  
Mediterranean Island ◽  
Water Holding

Abstract. Soil and biological soil crusts can emit nitrous acid (HONO) and nitric oxide (NO). The terrestrial ground surface in arid and semiarid regions is anticipated to play an important role in the local atmospheric HONO budget, deemed to represent one of the unaccounted-for HONO sources frequently observed in field studies. In this study HONO and NO emissions from a representative variety of soil and biological soil crust samples from the Mediterranean island Cyprus were investigated under controlled laboratory conditions. A wide range of fluxes was observed, ranging from 0.6 to 264 ng m−2 s−1 HONO-N at optimal soil water content (20–30 % of water holding capacity, WHC). Maximum NO-N fluxes at this WHC were lower (0.8–121 ng m−2 s−1). The highest emissions of both reactive nitrogen species were found from bare soil, followed by light and dark cyanobacteria-dominated biological soil crusts (biocrusts), correlating well with the sample nutrient levels (nitrite and nitrate). Extrapolations of lab-based HONO emission studies agree well with the unaccounted-for HONO source derived previously for the extensive CYPHEX field campaign, i.e., emissions from soil and biocrusts may essentially close the Cyprus HONO budget.

scholarly journals Emission of nitrous acid from soil and biological soil crusts represents a dominant source of HONO in the remote atmosphere in Cyprus

2017 ◽  
Author(s):  
Hannah Meusel ◽  
Alexandra Tamm ◽  
Uwe Kuhn ◽  
Dianming Wu ◽  
Anna Lena Leifke ◽  
...  
Keyword(s):  
Nitrous Acid ◽  
Biological Soil Crust ◽  
Ground Surface ◽  
Field Studies ◽  
Bare Soil ◽  
Biological Soil Crusts ◽  
Soil Crusts ◽  
Wide Range ◽  
Mediterranean Island ◽  
Water Holding

Abstract. Soil and biological soil crusts can emit nitrous acid (HONO) and nitric oxide (NO). The terrestrial ground surface in arid and semi-arid regions is anticipated to play an important role in the local atmospheric HONO budget, deemed to represent one of the unaccounted HONO sources frequently observed in field studies. In this study HONO and NO emissions from a representative variety of soil and biological soil crust samples from the Mediterranean island Cyprus were investigated under controlled laboratory conditions. A wide range of fluxes was observed, ranging from 0.6 to 264 ng m−2 s−1 HONO-N at optimal soil water content (20–30 % of water holding capacity, WHC). Maximum NO-N at this WHC fluxes were lower (0.8–121 ng m−2 s−1). Highest emissions of both reactive nitrogen species were found from bare soil, followed by light and dark cyanobacteria-dominated biological soil crusts (biocrusts), correlating well with the sample nutrient levels (nitrite and nitrate). Extrapolations of lab-based HONO emission studies agree well with the unaccounted HONO source derived previously for the extensive CYPHEX field campaign, i.e., emissions from soil and biocrusts may essentially close the Cyprus HONO budget.

scholarly journals Warming reduces the growth and diversity of biological soil crusts in a semi-arid environment: implications for ecosystem structure and functioning

2012 ◽  
Vol 367 (1606) ◽  
pp. 3087-3099 ◽  
Author(s):  
Cristina Escolar ◽  
Isabel Martínez ◽  
Matthew A. Bowker ◽  
Fernando T. Maestre
Keyword(s):  
Climate Change ◽  
Soil Stabilization ◽  
Arid Environment ◽  
Biological Soil Crusts ◽  
Water Dynamics ◽  
Annual Rainfall ◽  
Ecosystem Structure ◽  
Positive Effects ◽  
Soil Crusts ◽  
Semi Arid

Biological soil crusts (BSCs) are key biotic components of dryland ecosystems worldwide that control many functional processes, including carbon and nitrogen cycling, soil stabilization and infiltration. Regardless of their ecological importance and prevalence in drylands, very few studies have explicitly evaluated how climate change will affect the structure and composition of BSCs, and the functioning of their constituents. Using a manipulative experiment conducted over 3 years in a semi-arid site from central Spain, we evaluated how the composition, structure and performance of lichen-dominated BSCs respond to a 2.4°C increase in temperature, and to an approximately 30 per cent reduction of total annual rainfall. In areas with well-developed BSCs, warming promoted a significant decrease in the richness and diversity of the whole BSC community. This was accompanied by important compositional changes, as the cover of lichens suffered a substantial decrease with warming (from 70 to 40% on average), while that of mosses increased slightly (from 0.3 to 7% on average). The physiological performance of the BSC community, evaluated using chlorophyll fluorescence, increased with warming during the first year of the experiment, but did not respond to rainfall reduction. Our results indicate that ongoing climate change will strongly affect the diversity and composition of BSC communities, as well as their recovery after disturbances. The expected changes in richness and composition under warming could reduce or even reverse the positive effects of BSCs on important soil processes. Thus, these changes are likely to promote an overall reduction in ecosystem processes that sustain and control nutrient cycling, soil stabilization and water dynamics.

scholarly journals Metals in some dominant vascular plants, mosses, lichens, algae, and the biological soil crust in various types of terrestrial tundra, SW Spitsbergen, Norway

Polar Biology ◽  
2013 ◽  
Vol 36 (12) ◽  
pp. 1799-1809 ◽  
Author(s):  
B. Wojtuń ◽  
A. Samecka-Cymerman ◽  
K. Kolon ◽  
A. J. Kempers ◽  
G. Skrzypek
Keyword(s):  
Vascular Plants ◽  
Biological Soil Crust ◽  
Soil Crust
Sign in / Sign up

Export Citation Format

Share Document