Post-pyrogenic changes in vegetation cover and biological soil crust in steppe ecosystems

The study of the processes of restoration of species richness and productivity of steppe ecosystems after fires is an urgent problem that affects not only the conservation of biodiversity but also the maintenance of pasture resources. This article presents the results of a study of post-pyrogenic effects in steppe ecosystems, taking into account changes in the species composition of cyanoprokaryotes and algae that are art of the biological soil crust, which performs ecologically important functions in xerophytic ecosystems. The investigations were carried out in virgin and post-pyrogenic steppe ecosystems of the “Troitsk Clough” reserve (Zaporizhia region, Ukraine). For three years, the dynamics of the projective cover and the height of the vegetation cover in virgin areas of herbs-fescue-feather-grass and fescue-feather-grass steppes was studied as well as within two ecosystems of post-pyrogenic development after fires that occurred in the spring and winter periods. We discovered that restoration of the herbs-fescue-feather-grass and fescue-feather-grass steppes after fires occurs at different rates. The cause of the slow restoration of vegetation cover can be its severe damage by fire at the beginning of the vegetation season and the development of erosion processes. The number of species of cyanoprokaryotes and algae in the biological soil crust of virgin and post-pyrogenic ecosystems is not significantly different. It varies from 35 to 49 species. The greatest diversity is noted for Cyanoprokaryota. Chlorophyta is in the second place. Among the dominants, the filamentous forms of Cyanoprokaryota prevail. Nostoc edaphicum was noted as a nitrogen fixing representative. The similarity of the species lists of cyanoprokaryotes and algae of post-pyrogenic and virgin ecosystems, according to the calculated Jaccard coefficient, varies from 49.1% to 55.3%. This indicates a strong specificity of the composition of cyanoprokaryotes and algae in post-pyrogenic biological soil crusts. Changes in their composition reflect different stages of post-pyrogenic succession. In the first year after a fire, there is a slight increase in species richness, which is a consequence of the favorable effect of increasing the amount of mineral substances in the soil after the organic matter has burned out. The “pioneer” group includes: Phormidium autumnale, Ph. dimorphum, Ph. retzii, Ph. (Leptolyngbya) henningsii, Luticola mutica, Hantzschia amphioxys. Gradually this effect is leveled and the species richness of cyanoprokaryotes and algae is stabilized at a level peculiar for this type of ecosystem.

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Variation in Biological Soil Crust Bacterial Abundance and Diversity as a Function of Climate in Cold Steppe Ecosystems in the Intermountain West, USA

Microbial Ecology ◽

10.1007/s00248-017-0981-3 ◽

2017 ◽

Vol 74 (3) ◽

pp. 691-700 ◽

Cited By ~ 13

Author(s):

Erika S. Blay ◽

Stacy G. Schwabedissen ◽

Timothy S. Magnuson ◽

Ken A. Aho ◽

Peter P. Sheridan ◽

...

Keyword(s):

Bacterial Abundance ◽

Biological Soil Crust ◽

Soil Crust ◽

Intermountain West ◽

Steppe Ecosystems ◽

Abundance And Diversity

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Biological soil crust communities 12–16 years after wildfires in Idaho, USA

10.5194/bg-2017-178 ◽

2017 ◽

Author(s):

Heather T. Root ◽

John C. Brinda ◽

E. Kyle Dodson

Keyword(s):

Species Richness ◽

Functional Groups ◽

Fire Severity ◽

Biological Soil Crust ◽

Vascular Plant ◽

Fire Regimes ◽

Arid Ecosystems ◽

Plant Functional Groups ◽

Ecosystem Functions ◽

Soil Crust

Abstract. Changing fire regimes in western North America may impact biological soil crust (BSC) communities that influence many ecosystem functions, such as soil stability and C and N cycling. However, longer-term effects of wildfire on BSC abundance, species richness, functional groups, and ecosystem functions after wildfire (i.e. BSC resilience) is still poorly understood. We sampled BSC lichen and bryophyte communities at four sites in Idaho, USA, within foothill steppe communities that included wildfires from 12 to 16 years old. We established six plots outside each burn perimeter and compared them with six plots of varying severity within each fire perimeter at each site. BSC cover was most strongly negatively impacted by wildfire at sites that had well-developed BSC communities in adjacent unburned plots. BSC species richness was estimated to be 65 % greater in unburned plots compared with burned plots. In contrast, there was no evidence that vascular plant functional groups or fire severity (as measured by satellite metrics dNBR or RdNBR) significantly affected longer-term BSC responses. Three BSC functional groups (squamulose lichens, vagrant lichens, and tall turf mosses) exhibited a significant decrease in abundance in burned areas relative to adjacent unburned areas. The decreases in BSC cover and richness along with decreased abundance of several functional groups suggest that wildfire can negatively impact ecosystem function in these semi-arid ecosystems for at least one to two decades. This is a concern given that increased fire frequency is predicted for the region due to exotic grass invasion and climate change.

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Recovery of biological soil crust richness and cover 12–16 years after wildfires in Idaho, USA

Biogeosciences ◽

10.5194/bg-14-3957-2017 ◽

2017 ◽

Vol 14 (17) ◽

pp. 3957-3969 ◽

Cited By ~ 11

Author(s):

Heather T. Root ◽

John C. Brinda ◽

E. Kyle Dodson

Keyword(s):

Species Richness ◽

Functional Groups ◽

Fire Severity ◽

Biological Soil Crust ◽

Vascular Plant ◽

Plant Functional Groups ◽

Ecosystem Functions ◽

Soil Crust ◽

Differenced Normalized Burn Ratio ◽

Normalized Burn Ratio

Abstract. Changing fire regimes in western North America may impact biological soil crust (BSC) communities that influence many ecosystem functions, such as soil stability and C and N cycling. However, longer-term effects of wildfire on BSC abundance, species richness, functional groups, and ecosystem functions after wildfire (i.e., BSC resilience) are still poorly understood. We sampled BSC lichen and bryophyte communities at four sites in Idaho, USA, within foothill steppe communities that included wildfires from 12 to 16 years old. We established six plots outside each burn perimeter and compared them with six plots of varying severity within each fire perimeter at each site. BSC cover was most strongly negatively impacted by wildfire at sites that had well-developed BSC communities in adjacent unburned plots. BSC species richness was estimated to be 65 % greater in unburned plots compared with burned plots, and fire effects did not vary among sites. In contrast, there was no evidence that vascular plant functional groups or fire severity (as measured by satellite metrics differenced normalized burn ratio (dNBR) or relativized differenced normalized burn ratio (RdNBR)) significantly affected longer-term BSC responses. Three large-statured BSC functional groups that may be important in controlling wind and water erosion (squamulose lichens, vagrant lichens, and tall turf mosses) exhibited a significant decrease in abundance in burned areas relative to adjacent unburned areas. The decreases in BSC cover and richness along with decreased abundance of several functional groups suggest that wildfire can negatively impact ecosystem function in these semiarid ecosystems for at least 1 to 2 decades. This is a concern given that increased fire frequency is predicted for the region due to exotic grass invasion and climate change.

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The effect of wildfires on vegetation cover and dune activity in Australia's desert dunes: a multisensor analysis

International Journal of Wildland Fire ◽

10.1071/wf10150 ◽

2012 ◽

Vol 21 (4) ◽

pp. 459 ◽

Cited By ~ 20

Author(s):

N. Levin ◽

S. Levental ◽

H. Morag

Keyword(s):

Vegetation Cover ◽

Vegetation Index ◽

Biological Soil Crust ◽

Soil Crust ◽

Spectral Indices ◽

Spatial And Temporal Scales ◽

Normalised Difference Vegetation Index ◽

Sand Movement ◽

Desert Dunes ◽

Dune Activity

Most of Australia’s desert dune fields are stable; however, wildfires may reduce vegetation and biological soil crust cover so that sand movement may take place until vegetation recovers. In this study, we aimed to study the recovery rate of vegetation cover in spinifex (Triodia)-dominated desert dunes following wildfires using satellite imagery-derived spectral indices to: (1) determine for how long after fire these dunes may be active until critical levels of vegetation cover are attained; (2) determine which spectral index is the most suitable for monitoring vegetation recovery in this area. We have used a combination of MODIS, Landsat, Aster and QuickBird images to analyse vegetation cover following fire at various spatial and temporal scales, in the Great Victoria Desert, WA. The following spectral indices were compared: Brightness Index, Biological Soil Crust Index (BSCI), Crust Index, Enhanced Vegetation Index, Normalised Burn Ratio, Normalised Difference Vegetation Index, Soil Adjusted Vegetation Index and the Stress-related Vegetation Index. The BSCI was found to outperform the other spectral indices in monitoring vegetation cover in this area. Whereas full recovery of vegetation following wildfires in the study area was attained only after 25–30 years, critical thresholds of vegetation cover limiting sand movement were attained after just 1–5 years. The frequency and intensity of wildfires is therefore an important factor controlling dune activity in Australia’s deserts.

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Do biotic interactions modulate ecosystem functioning along stress gradients? Insights from semi-arid plant and biological soil crust communities

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2010.0016 ◽

2010 ◽

Vol 365 (1549) ◽

pp. 2057-2070 ◽

Cited By ~ 93

Author(s):

Fernando T. Maestre ◽

Matthew A. Bowker ◽

Cristina Escolar ◽

María D. Puche ◽

Santiago Soliveres ◽

...

Keyword(s):

Climate Change ◽

Species Richness ◽

Abiotic Stress ◽

Ecosystem Functioning ◽

Biological Soil Crust ◽

Biotic Interactions ◽

Arid Ecosystems ◽

Soil Crust ◽

Stress Gradients ◽

Semi Arid

Climate change will exacerbate the degree of abiotic stress experienced by semi-arid ecosystems. While abiotic stress profoundly affects biotic interactions, their potential role as modulators of ecosystem responses to climate change is largely unknown. Using plants and biological soil crusts, we tested the relative importance of facilitative–competitive interactions and other community attributes (cover, species richness and species evenness) as drivers of ecosystem functioning along stress gradients in semi-arid Mediterranean ecosystems. Biotic interactions shifted from facilitation to competition along stress gradients driven by water availability and temperature. These changes were, however, dependent on the spatial scale and the community considered. We found little evidence to suggest that biotic interactions are a major direct influence upon indicators of ecosystem functioning (soil respiration, organic carbon, water-holding capacity, compaction and the activity of enzymes related to the carbon, nitrogen and phosphorus cycles) along stress gradients. However, attributes such as cover and species richness showed a direct effect on ecosystem functioning. Our results do not agree with predictions emphasizing that the importance of plant–plant interactions will be increased under climate change in dry environments, and indicate that reductions in the cover of plant and biological soil crust communities will negatively impact ecosystems under future climatic conditions.

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Biological soil crust distribution on the Boardman Conservation Area

10.3411/col.04072147 ◽

2010 ◽

Cited By ~ 1

Author(s):

Adrien Elseroad ◽

Joseph St. Peter ◽

Maile Uchida

Keyword(s):

Biological Soil Crust ◽

Soil Crust ◽

Conservation Area

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Functional ecology of the biological soil crust in semiarid SE Spain: sun and shade populations of Diploschistes diacapsis (Ach.) Lumbsch.

The Lichenologist ◽

10.1017/s0024282905015021 ◽

2005 ◽

Vol 37 (5) ◽

pp. 425-432 ◽

Cited By ~ 38

Author(s):

Ana PINTADO ◽

Leopoldo G. SANCHO ◽

T. G. Allan GREEN ◽

José Manuel BLANQUER ◽

Roberto LÁZARO

Keyword(s):

Water Content ◽

Chlorophyll Content ◽

Unit Area ◽

Biological Soil Crust ◽

Dry Weight ◽

Mean Annual Precipitation ◽

Plant Colonization ◽

Soil Crust ◽

Active Time ◽

Exposed Population

The Tabernas badlands in semiarid south-east Spain is one of the driest regions in Europe with a mean annual precipitation of c. 240 mm. The landscape is deeply dissected, with canyons, ramblas and sparsely vegetated eroded badland slopes. The vegetation is predominantly a biological soil crust consisting of different types of lichen-rich communities, one of the more conspicuous being dominated by Diploschistes diacapsis (Ach.) Lumbsch. This lichen is mainly restricted to the north- facing slopes, where it forms extensive whitish carpets and probably plays an important role in preventing erosion of the slopes and allowing plant colonization. South-facing slopes are much more eroded and generally lack vegetation. %The photosynthetic performance of north (shade) and south-facing (sun) populations of D. diacapsis was studied to determine if these different populations showed any adaptations to the microclimatic conditions of their individual habitats. The response of CO2 exchange to light intensity, temperature and water content was measured under controlled conditions in the laboratory. Dry weight-based net photosynthetic rates were higher in the southern-exposed population but quantum efficiency, and light compensation points were similar. Thallus weight per unit area (LMA) was considerably higher for shade specimens but maximum water content and optimal water content were very similar and chlorophyll content on a dry weight basis was also similar. Chlorophyll content on an area basis was higher in the northern-exposed population and always much larger than those reported in other studies on the same species (up to 8 times larger) with the result that NP values on a chlorophyll basis were relatively low. The larger LMA meant that shade thalli stored more water per unit area which should ensure longer active periods than sun thalli. The results support a strategy pair of high NP and short active time versus low NP and long active time, both having been reported for other soil crust species. However, the visibly larger biomass of the shade D. diacapsis suggests that the lichen is at the limit of its adaptability in these habitats.

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