Microbiotic soil crusts - a review of their roles in soil and ecological processes in the rangelands of Australia

Soil Research ◽  
1994 ◽  
Vol 32 (3) ◽  
pp. 389 ◽  
Author(s):  
DJ Eldridge ◽  
RSB Greene
Keyword(s):  
Vascular Plants ◽  
Surface Condition ◽  
Vascular Plant ◽  
Plant Cover ◽  
Chemical Properties ◽  
Soil Surface ◽  
Ecological Processes ◽  
Soil Crusts ◽  
Soil Surface Roughness ◽  
Microbiotic Crusts

Microbiotic crusts are assemblages of non-vascular plants (mosses, liverworts, algae, lichens, fungi, bacteria and cyanobacteria) which form intimate associations with surface soils. They play a major role in infiltration processes through changes to soil physico-chemical properties, and through their influence on soil surface roughness. Whilst some research suggests that they may restrict infiltration, Australian experience is that they are generally associated with enhanced infiltration. Unlike physical soil crusts, microbiotic crusts stabilize the soil against water and wind erosion, increasing landscape stability, particularly in areas of low vascular plant cover. Microbiotic crusts are thus useful indicators of soil surface condition, and cyanobacteria in the crusts fix nitrogen which may be utilized by developing vascular plant seedlings. Little is known, however, about how they interact with vascular plants and soil invertebrates. Their role in rangeland ecosystems has received renewed attention over the past few years with an increasing interest in ecologically sustainable development of arid and semi-arid grazing systems. In this review we discuss the characteristics and distribution of microbiotic crusts in the rangelands of Australia, their roles in soil and ecological processes and the impacts of fire and grazing. Finally we propose a new system for classifying crusts into functional groups and identify areas requiring further investigation.

In memory of Vera Antonovna Martynenko (1936-2018)

2018 ◽  
pp. 149-154
Keyword(s):  
Vascular Plants ◽  
Ussr Academy ◽  
Vascular Plant ◽  
Plant Cover ◽  
Komi Republic ◽  
Great Contribution ◽  
North East ◽  
The North ◽  
Natural Flora

Vera Antonovna Martynenko (17.02.1936–06.01.2018) — famous specialist in the field of studying vascular plant flora and vegetation of the Far North, the Honored worker of the Komi Republic (2006), The Komi Republic State Scientific Award winner (2000). She was born in the town Likhoslavl of the Kali­nin (Tver) region. In 1959, Vera Antonovna graduated from the faculty of soil and biology of the Leningrad State University and then moved to the Komi Branch of USSR Academy of Science (Syktyvkar). From 1969 to 1973 she passed correspondence postgraduate courses of the Komi Branch of USSR Academy of ­Science. In 1974, she received the degree of candidate of biology (PhD) by the theme «Comparative analysis of the boreal flora at the Northeast European USSR» in the Botanical Institute (St. Petersburg). In 1996, Vera Antonovna received the degree of doctor of biology in the Institute of plant and animal ecology (Ekaterinburg) «Flora of the northern and mid subzones of the taiga of the European North-East». The study and conservation of species and coenotical diversity of the plant world, namely the vascular plants flora of the Komi Republic and revealing its transformation under the anthropogenic influence, was in the field of V. A. Martynenko’ scientific interests. She made great contribution to the study of the Komi Republic meadow flora and the pool of medi­cinal plants. She performed inventorying and mapping the meadows of several agricultural enterprises of the Republic, revealed the species composition and places for harvesting medicinal plants and studied their productivity in the natural flora of the boreal zone. The results of her long-term studies were used for making the NPA system and the Red Book of the Komi Republic (1998 and 2009). Vera Antonovna participated in the research of the influence of placer gold mining and oil development on the natural ecosystems of the North, and developed the method of long-term monitoring of plant cover. Results of these works are of high practical value. V. A. Martynenko is an author and coauthor of more than 130 scientific publications. The most important jnes are «Flora of Northeast European USSR» (1974, 1976, and 1977), «Floristic composition of fodder lands of the Northeast Europe» (1989), «The forests of the Komi Republic» (1999), «Forestry of forest resources of the Komi Republic» (2000), «The list of flora of the Yugyd va national park» (2003), «The guide for vascular plants of the Syktyvkar and its vicinities» (2005), «Vascular plants of the Komi Republic» (2008), and «Resources of the natural flora of the Komi Republic» (2014). She also was an author of «Encyclopedia of the Komi Republic» (1997, 1999, and 2000), «Historical and cultural atlas of the Komi Republic» (1997), «Atlas of the Komi Republic» (2001, 2011). V. A. Martynenko made a great contribution to the development of the botanical investigations in the North. Since 1982, during more than 10 years, she was the head of the Department of the Institute of Biology. Three Ph. D. theses have been completed under her leadership. Many years, she worked actively in the Dissertation Council of the Institute of biology Komi Scientific Centre UrB RAS.  The death of Vera Antonovna Martynenko is a heavy and irretrievable loss for the staff of the Institute of Biology. The memory of Vera Antonovna will live in her numerous scientific works, the hearts of students and colleagues.

BIODIVERSITY AND INTERSLOPE DIVERGENCE OF VASCULAR PLANTS CAUSED BY MICROCLIMATIC DIFFERENCES AT “EVOLUTION CANYON”, LOWER NAHAL OREN, MOUNT CARMEL, ISRAEL

1999 ◽  
Vol 47 (1) ◽  
pp. 49-59 ◽  
Author(s):  
Eviatar Nevo ◽  
Ori Fragman ◽  
Amots Dafni ◽  
Avigdor Beiles
Keyword(s):  
Natural Selection ◽  
Species Diversity ◽  
Vascular Plants ◽  
Vascular Plant ◽  
Plant Cover ◽  
Life Forms ◽  
Valley Bottom ◽  
Content Sharing ◽  
The North ◽  
Evolution Canyon

Species diversity of plants was recorded in 1992 and 1993 at seven stations of the “Evolution Canyon” microsite. Higher solar radiation on the South-Facing Slope (SFS) causes warm, xeric savannoid formation versus temperate, cool, mesic, dense maquis on the North-Facing Slope (NFS), and riverine, segetal plant formations on the Valley Bottom (VB). In an area of 7000 m2, we recorded 320 vascular plant species in 217 genera and 59 families. Plant cover varied from 35% (SFS) to 150% (NFS). Annuals predominated among all life forms (61.3% of all species). SFS and NFS varied in species content, sharing only 31–18% of species. Phytogeographical types varied among the two slopes and valley bottom. Inter-and intraslope species composition varied drastically due to differential microclimatic stresses, thereby demonstrating at a microscale natural selection in action.

scholarly journals Unassisted establishment of biological soil crusts on dryland road slopes

Web Ecology ◽  
2019 ◽  
Vol 19 (1) ◽  
pp. 39-51 ◽  
Author(s):  
Laura Concostrina-Zubiri ◽  
Juan M. Arenas ◽  
Isabel Martínez ◽  
Adrián Escudero
Keyword(s):  
Species Composition ◽  
Soil Properties ◽  
Vascular Plant ◽  
Plant Cover ◽  
Critical Role ◽  
Biological Soil Crusts ◽  
Functional Structure ◽  
Ecosystem Recovery ◽  
Natural Habitats ◽  
Soil Crusts

Abstract. Understanding patterns of habitat natural recovery after human-made disturbances is critical for the conservation of ecosystems under high environmental stress, such as drylands. In particular, the unassisted establishment of nonvascular plants such as biological soil crusts or biocrust communities (e.g., soil lichens, mosses and cyanobacteria) in newly formed habitats is not yet fully understood. However, the potential of biocrusts to improve soil structure and function at the early stages of succession and promote ecosystem recovery is enormous. In this study, we evaluated the capacity of lichen biocrusts to spontaneously establish and develop on road slopes in a Mediterranean shrubland. We also compared taxonomic and functional diversity of biocrusts between road slopes and natural habitats in the surroundings. Biocrust richness and cover, species composition, and functional structure were measured in 17 road slopes (nine roadcuts and eight embankments) along a 13 km highway stretch. Topography, soil properties and vascular plant communities of road slopes were also characterized. We used Kruskal–Wallis tests and applied redundancy analysis (RDA) to test the effect of environmental scenario (road slopes vs. natural habitat) and other local factors on biocrust features. We found that biocrusts were common in road slopes after ∼20 years of construction with no human assistance needed. However, species richness and cover were still lower than in natural remnants. Also, functional structure was quite similar between roadcuts (i.e., after soil excavation) and natural remnants, and topography and soil properties influenced species composition while environmental scenario type and vascular plant cover did not. These findings further support the idea of biocrusts as promising restoration tools in drylands and confirm the critical role of edaphic factors in biocrust establishment and development in land-use change scenarios.

scholarly journals Vascular plants affect properties and decomposition of moss-dominated peat, particularly at elevated temperatures

2020 ◽  
Vol 17 (19) ◽  
pp. 4797-4813
Author(s):  
Lilli Zeh ◽  
Marie Theresa Igel ◽  
Judith Schellekens ◽  
Juul Limpens ◽  
Luca Bragazza ◽  
...  
Keyword(s):  
Climate Change ◽  
Vascular Plants ◽  
Elevated Temperatures ◽  
Vascular Plant ◽  
Chemical Properties ◽  
Pyrolysis Product ◽  
Calluna Vulgaris ◽  
Mean Annual Temperature ◽  
Multiple Parameters ◽  
Vegetation Shift

Abstract. Peatlands, storing significant amounts of carbon, are extremely vulnerable to climate change. The effects of climate change are projected to lead to a vegetation shift from Sphagnum mosses to sedges and shrubs. Impacts on the present moss-dominated peat remain largely unknown. In this study, we used a multiproxy approach to investigate the influence of contrasting vascular plant types (sedges, shrubs) on peat chemistry and decomposition. Peat cores of 20 cm depth and plant material (Sphagnum spp., Calluna vulgaris and Eriophorum vaginatum) from two ombrotrophic peatlands in the Italian Alps with a mean annual temperature difference of 1.4 ∘C were analyzed. Peat cores were taken under adjacent shrub and sedge plants growing at the same height above the water table. We used carbon, nitrogen and their stable isotopes to assess general patterns in the degree of decomposition across sampling locations and depths. In addition, analytical pyrolysis was applied to disentangle effects of vascular plants (sedge, shrub) on chemical properties and decomposition of the moss-dominated peat. Pyrolysis data confirmed that Sphagnum moss dominated the present peat irrespective of depth. Nevertheless, vascular plants contributed to peat properties as revealed by, e.g., pyrolysis products of lignin. The degree of peat decomposition increased with depth as shown by, e.g., decreasing amounts of the pyrolysis product of sphagnum acid and increasing δ13C with depth. Multiple parameters also revealed a higher degree of decomposition of Sphagnum-dominated peat collected under sedges than under shrubs, particularly at the high temperature site. Surprisingly, temperature effects on peat decomposition were less pronounced than those of sedges. Our results imply that vascular plants affect the decomposition of the existing peat formed by Sphagnum, particularly at elevated temperature. These results suggest that changes in plant functional types may have a stronger impact on the soil carbon feedback in a warmer world than hitherto assumed.

Testing sudden shifts in drylands through manipulative mesocosm experiments

2020 ◽  
Author(s):  
Susana Bautista ◽  
Francisco Fornieles ◽  
David Fuentes ◽  
Anna M Urgeghe ◽  
Diana Turrión ◽  
...  
Keyword(s):  
Experimental Approach ◽  
Experimental Testing ◽  
Surface Condition ◽  
Plant Cover ◽  
Soil Surface ◽  
Bare Soil ◽  
Mesocosm Experiments ◽  
Small Change ◽  
The Impact ◽  
Lower Capacity

<p>A variety of theoretical and observational works indicate that drylands may experience sudden shifts from functional to degraded states in response to gradual increases in human and climatic pressures. However, there is little experimental testing of the factors and processes that control sudden shifts in drylands. Adopting a combination of mesocosms and manipulative experimental approach, we assessed the occurrence of sudden transitions towards degraded states in response to increasing pressure, and investigated the mechanisms underlying the observed dynamics. We mimicked a gradually increasing pressure of grazing and wood gathering by removing increasing amounts of vegetation on a series of experimental plots and mesocosms. We then monitored the impact of such gradient of pressure on runoff and sediment yield, vegetation dynamics, bare-soil connectivity and soil-surface condition over a 7-year period.  Overall, our results support that decreasing plant cover nonlinearly increases the loss of resources from the system and may trigger a change to a degraded state. Within the range from 40% to 30 % vegetation cover, a small change in the cover percentage resulted in a turning point in both the vegetation and the hydrological dynamics, driving the system to a new state that exhibited lower capacity for resource conservation all over the study period.</p>

Root growth in a polar semidesert environment

1978 ◽  
Vol 56 (20) ◽  
pp. 2470-2490 ◽  
Author(s):  
Katherine L. Bell ◽  
L. C. Bliss
Keyword(s):  
Root Growth ◽  
Vascular Plants ◽  
Vascular Plant ◽  
Plant Cover ◽  
Root Systems ◽  
High Arctic ◽  
Moisture Gradient ◽  
Small Roots ◽  
Total Plant ◽  
Root:Shoot Ratios

Within the northwestern islands of the High Arctic, the vegetation and flora of King Christian Island are very representative. Five plant communities were recognized in a moisture gradient from a moss–rush moist meadow with 22 species of vascular plants and 13% cover (total plant cover 93%) to lichen barrens on low ridges with 8 species of vascular plants and 3% cover (total plant cover 24%). Root systems of 30 of the 34 known vascular plant species were examined. Root:shoot ratios (alive) are generally 0.2 to 0.7. Roots are estimated to live 1.5 years in Phippsia algida, 3.4–3.7 years in Alopecurus alpinus and Puccinellia vaginata, and 7–13 years in Luzula nivalis, L. confuse), and Cerastium arcticum. Optimal root growth occurs at 12 to 20 °C but cold field soils (1 to 3 °C) reduce these rates by 90%. Root growth was also reduced by low soil water potentials (< − 14 bars (1 bar = 100 kPa)), conditions seldom encountered in these sites. Limited root growth due to cold soils is combined with the adaptive advantages of small roots to produce small plants and sparse cover in these polar semidesert lands.

scholarly journals Reintroduction of fen plant communities on a degraded minerotrophic peatland

Botany ◽  
2016 ◽  
Vol 94 (11) ◽  
pp. 1041-1051 ◽  
Author(s):  
Line Rochefort ◽  
Marie-Claire LeBlanc ◽  
Vicky Bérubé ◽  
Sandrine Hugron ◽  
Stéphanie Boudreau ◽  
...  
Keyword(s):  
Vascular Plants ◽  
Vascular Plant ◽  
Plant Cover ◽  
Water Levels ◽  
Site Conditions ◽  
Effective Solution ◽  
Restoration Techniques ◽  
Minerotrophic Peatland ◽  
Fen Plants ◽  
Surface Peat

We have developed an approach to restore bogs after peat extraction, but, when sedge-peat layers are exposed, the minerotrophic remnant peat conditions require restoration towards a fen ecosystem. Three restoration techniques, all including rewetting actions, were tested to assist fen vegetation recovery. None of the restoration techniques were effective at establishing fen bryophytes. However, for vascular plants, two techniques gave promising results in terms of species composition, although the vascular plant cover remained lower than in the reference fens. Depending on the site conditions, we suggest applying two restoration techniques to restore peatlands in areas of exposed sedge peat. In areas where sparse cover of fen species may have spontaneously established, rewetting should be carried out to raise water levels and create favourable conditions for their expansion. In areas covered with undesirable species or with inadequate topography for rewetting, surface peat should be remodeled and vegetation introduced. Since mechanized diaspore transfer did not result in a satisfactory cover of fen plants, other means of introduction could be considered, alone or in combination. A complementary fertilization experiment showed that fertilization with phosphorus could be an effective solution to enhance the establishment of mechanically introduced plant diaspores.

scholarly journals Vascular plants affect properties and decomposition of moss-dominated peat, particularly at elevated temperatures

2020 ◽  
Author(s):  
Lilli Zeh ◽  
Theresa Marie Igel ◽  
Judith Schellekens ◽  
Juul Limpens ◽  
Luca Bragazza ◽  
...  
Keyword(s):  
Climate Change ◽  
Vascular Plants ◽  
Elevated Temperatures ◽  
Vascular Plant ◽  
Chemical Properties ◽  
Pyrolysis Product ◽  
Calluna Vulgaris ◽  
Mean Annual Temperature ◽  
Multiple Parameters ◽  
Vegetation Shift

Abstract. Peatlands, storing significant amounts of carbon are extremely vulnerable to climate change. The effects of climate change are projected to lead to a vegetation shift from Sphagnum mosses to sedges and shrubs. Impacts on the present moss-dominated peat remain largely unknown. In this study, we used a multi proxy approach to investigate the influence of contrasting vascular plant types (sedges, shrubs) on peat chemistry and decomposition. Peat cores of 20 cm depth and plant material (Sphagnum spp., Calluna vulgaris, Eriophorum vaginatum) from two ombrotrophic peatlands in the Italian Alps with a mean annual temperature difference of 1.4 °C were analysed. Peat cores were taken under adjacent shrub and sedge plants growing at the same height above the water table. We used carbon, nitrogen and their stable isotopes to assess general patterns in the degree of decomposition across sampling locations and depths. In addition, analytical pyrolysis was applied to disentangle effects of vascular plants (sedge, shrub) on chemical properties and decomposition of the moss-dominated peat. Pyrolysis data confirmed that Sphagnum moss dominated the present peat irrespectively of depth. Nevertheless, vascular plants contributed to peat properties as revealed by e.g. pyrolysis products of lignin. The degree of peat decomposition increased with depth as shown by e.g. decreasing amounts of the pyrolysis product of sphagnum acid and increasing δ13C with depth. Multiple parameters also revealed a higher degree of decomposition of Sphagnum-dominated peat collected under sedges than under shrubs, particularly at the high temperature site. Surprisingly, temperature effects on peat decomposition were less pronounced than those of sedges. Our results imply that vascular plants affect the decomposition of the existing peat formed by Sphagnum, particularly at elevated temperature. These results suggest that changes in plant functional types may have a stronger impact on the soil carbon feedback in a warmer world than hitherto assumed.

The precursor environment for vascular plant colonization

1985 ◽  
Vol 309 (1138) ◽  
pp. 143-145 ◽  
Keyword(s):  
Land Surface ◽  
Vascular Plants ◽  
Vascular Plant ◽  
Plant Cover ◽  
Biologically Active ◽  
Plant Colonization ◽  
Physico Chemical ◽  
History Of ◽  
Lower Palaeozoic ◽  
Soil Forming Processes

There is evidence, although inconclusive, that a biologically active soil cover existed long before the late Silurian. The earliest vascular plants may have colonized a land surface containing well-developed soils which were functioning biologically and biochemically in similar ways to modern soils. In any discussion of the late Silurian-early Devonian ‘invasion of the land’, two basic questions arise in relation to the history of the land cover and its soils: (i) Did vascular plants colonize a barren landscape or did biologically functioning soils already exist? (ii) What changes did the vascular plant cover cause to the land surface and its soils? This latter question has been tackled by Retallack (this symposium) and the following is a discussion of some aspects of the former. Many soil-forming processes are purely physical or physico-chemical in origin and examples of such pedogenic modifications of the land surface have now been documented from the Precambrian and lower Palaeozoic (Retallack 1981). However, there is also some evidence that these early soils were biologically active and were associated with microbial communities. Golubic & Campbell (1979) have compared the mid Precambrian microfossil, Eosynechnococcus moorei Hofmann with the extant cyanobacterium Gloeothece coerulea Geitler, which is a subaerial form. They have suggested that prokaryotic communities may have colonized the land surface as long ago as the early Precambrian. Organic-rich palaeosols are known from Blind River Formation of Ontario (Campbell 1979) which is 2.4 Ga old.

Differentiation of new coenomorph in context of the Belgard’s ecomorph system development

2017 ◽  
Vol 28 (1-2) ◽  
pp. 28-35 ◽  
Author(s):  
B. A. Baranovski
Keyword(s):  
Environmental Factors ◽  
Plant Species ◽  
Vascular Plants ◽  
Deciduous Forest ◽  
System Development ◽  
Vascular Plant ◽  
Tabular Form ◽  
Ecological Scales ◽  
The One ◽  
Different Levels

Nowadays, bioecological characteristics of species are the basis for flora and vegetation studying on the different levels. Bioecological characteristics of species is required in process of flora studying on the different levels such as biotopes or phytocenoses, floras of particular areas (floras of ecologically homogeneous habitats), and floras of certain territories. Ramensky scale is the one of first detailed ecological scales on plant species ordination in relation to various environmental factors; it developed in 1938 (Ramensky, 1971). A little later (1941), Pogrebnyak’s scale of forest stands was proposed. Ellenberg’s system developed in 1950 (Ellenberg, 1979) and Tsyganov’s system (Tsyganov, 1975) are best known as the systems of ecological scales on vascular plant species; these systems represent of habitat detection by ecotopic ecomorphs of plant species (phytoindication). Basically, the system proposed by Alexander Lyutsianovich Belgard was the one of first system of plant species that identiified ectomorphs in relation to environmental factors. As early as 1950, Belgard developed the tabulated system of ecomorphs using the Latin ecomorphs abbreviation; he also used the terminology proposed in the late 19th century by Dekandol (1956) and Warming (1903), as well as terminology of other authors. The article analyzes the features of Belgard’s system of ecomorphs on vascular plants. It has certain significance and advantages over other systems of ecomorphs. The use of abbreviated Latin names of ecomorphs in tabular form enables the use shortened form of ones. In the working scheme of Belgard’s system of ecomorphs relation of species to environmental factors are represented in the abbreviated Latin alphabetic version (Belgard, 1950). Combined into table, the ecomorphic analysis of plant species within association (ecological certification of species), biotope or area site (water area) gives an explicit pattern on ecological structure of flora within surveyed community, biotope or landscape, and on environmental conditions. Development and application by Belgrard the cenomorphs as «species’ adaptation to phytocenosis as a whole» were completely new in the development of systems of ecomorphs and, in this connection, different coenomorphs were distinguished. Like any concept, the system of ecomorphs by Belgard has the possibility and necessity to be developed and added. Long-time researches and analysis of literature sources allow to propose a new coenomorph in the context of Belgard’s system of ecomorphs development: silvomargoant (species of forest margin, from the Latin words margo – edge, boundary (Dvoretsky, 1976), margo – margin, ad margins silvarum – along the deciduous forest margins). As an example of ecomorphic characterization of species according to the system of ecomorphs by Belgard (when the abbreviated Latin ecomorph names are used in tabular form and the proposed cenomorph is used), it was given the part of the table on vascular plants ecomorphs in the National Nature Park «Orelsky» (Baranovsky et al). The Belgard’s system of ecomorphs is particularly convenient and can be successfully applied to data processing in the ecological analysis of the flora on wide areas with significant species richness, and the proposed ecomorph will be another necessary element in the Belgard’s system of ecomorphs. 

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