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.

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.

Tree pasture interactions at a range of tree densities in an agroforestry experiment. I. Rooting patterns

1990 ◽  
Vol 41 (4) ◽  
pp. 683 ◽  
Author(s):  
J Eastham ◽  
CW Rose
Keyword(s):  
Root Growth ◽  
Root Systems ◽  
Tree Density ◽  
Root Production ◽  
Total Length ◽  
Rooting Patterns ◽  
Root:Shoot Ratios

The effects of tree density on the distribution of tree and pasture roots under an agroforestry experiment were investigated. Trees were planted in a Nelder fan design, and three planting densities of 2150,304 and 82 stems per hectare were chosen for this study. Proximity to trees and increase in tree density reduced pasture root growth, with lowest concentrations of pasture roots occurring under the highest tree density. Tree root systems were deeper and denser at high tree densities, although total length and mass of roots produced per tree decreased with increasing tree density. Tree root:shoot ratios increased as tree density decreased owing to greater root production at low tree densities.

Microscale pattern of vascular plant distribution in two high arctic plant communities

1984 ◽  
Vol 62 (10) ◽  
pp. 2033-2042 ◽  
Author(s):  
E. H. Sohlberg ◽  
L. C. Bliss
Keyword(s):  
Distribution Pattern ◽  
Vascular Plants ◽  
Vascular Plant ◽  
Extreme Environments ◽  
Niche Differentiation ◽  
Bare Soil ◽  
High Arctic ◽  
Plant Distribution ◽  
Wind Speeds ◽  
Point Quadrat

Microscale pattern is of crucial importance in determining the distribution of vascular plants in the extreme environments of the High Arctic. Point-quadrat analysis of the distribution of the vascular plants in a mesic cryptogam–herb meadow and a xeric Puccinellia barren found a nonrandom distribution of vascular species. Most species were found growing in moss turfs versus crustose lichen or bare soil surfaces in the meadow and in desiccation cracks in the barren. Two species showed an opposite distribution pattern in the meadow indicating that incipient niche differentiation occurs in the High Arctic. Quadrat sampling showed that seed distribution was random in the meadow and only slightly skewed toward cracks in the barren. Microsites appeared to be crucial to the seedling establishment and adult distribution pattern for Papaver radicatum but less important for Ranunculus sabinei. Microclimate analyses showed that soil temperatures were higher, wind speeds were lower, soil moisture content was greater, and nitrate levels were higher in the microsites usually preferred by plants.

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.

Vascular plant communities of a polar oasis at Alexandra Fiord (79° N), Ellesmere Island, Canada

1989 ◽  
Vol 67 (4) ◽  
pp. 1126-1136 ◽  
Author(s):  
M. Muc ◽  
B. Freedman ◽  
J. Svoboda
Keyword(s):  
Cluster Analysis ◽  
Plant Species ◽  
Plant Community ◽  
Plant Communities ◽  
Vascular Plants ◽  
Vascular Plant ◽  
Detrended Correspondence Analysis ◽  
High Arctic ◽  
Ellesmere Island ◽  
Community Types

A cluster analysis was used to apportion 136 stands in a High Arctic lowland among six vascular plant community types. These communities are described on the basis of the average prominence values of vascular species and the total cover of macroalgae, bryophytes, lichens, and vascular plants within the designated clusters of stands. The relationships among the community types was explored by a detrended correspondence analysis. The ordination of stands showed considerable floristic overlap among the most widespread plant communities on the lowland. This largely reflects the microtopographic heterogeneity of the sites, the relatively depauperate flora of the High Arctic, and the considerable ecological amplitude of the most prominent vascular plant species.

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.

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.

Zonation in the plant cover on the Wrangel Island: syntaxonomical approach

2013 ◽  
pp. 89-121 ◽  
Author(s):  
S. S. Kholod
Keyword(s):  
Vascular Plants ◽  
Plant Cover ◽  
Arctic Tundra ◽  
High Arctic ◽  
Horizontal Structure ◽  
Wrangel Island ◽  
Number Of Species ◽  
The Status ◽  
Minimum Number ◽  
Altitudinal Belts

Hierarchical subdivision of the Wrangel Island was realized using syntaxonomic method. Following criteria were used: syntaxonomic spectrum and percentage share of syntaxa on zonal and intrazonal sites, the status of syntaxa in the system of altitudinal belts, the indexes of zonation and intrazonation, the index of dissimilarity between syntaxa (І-diversity) and mean number of species per relevй. The system of zonocontinuums and the criterion of typomorphic groups were applied to represent the character of syntaxa distribution. Furthermore, the indexes of “species-area relationships”, zonal-geographical groups of species, cover of the different groups of species and its variation, horizontal structure of communities and above ground phytomass were reviewed. All numerical characteristics allowed to make a differentiation of the island vegetation between 4 variants. Among these 2 ones are southern and nothern variants of arctic tundra subzones, 1 — is northern variant of typical tundra subzone and 1 — is southern (coastal) variant of polar deserts. The last are delimited fr om other zonal categories in highest rank —as geobotanical zone. They are characterized by minimum number of syntaxa in zonal sites (4) and in flood-plains (2), absence of any syntaxa at the slopes of southern exposure. All other indexes of diversity are of a least value: dissimilarity between syntaxa (43.7), and average number of species in relevй (5.9). Differentiate syntaxa for all sites (except plakkat) and typomorphic groups are absent. It is a least value of і-diversity: the parameter b1 in regression equation is1.17. Moreover, the cover of vascular plants decreases to 10–20 %, but cover of lichens increases to 30 %. The cover of bryophytes and all vegetation are characterized by essential changes of variation coefficient (0.6–0.7 and 0.4–0.5 respectively), above ground phytomass of vascular plants is decreases to 49.9 g/m2. The part of arctic zonal-geographical groups is increases greatly to 61.4 %, but total part of hypoarctic and boreal is decreases to 3.8 %. Sporadic-spotted type of horizontal structure is exclusively peculiar to this zone. Northern variant of typical tundra is characterized by a relatively large number of syntaxa at slopes of southern exposure (19) and high value of index of abruptness (0.56). Number of syntaxa with diagnostic meaning of altitudinal changes is greater — 13. The index of І-diversity by means average number of species in relevй is 9.5 and by means dissimilarity between syntaxa is 55.1 %. High diversity of syntaxa (9) differentiating at slopes of southern exposure is inherent to this zonal variant. Besides, large role of hypoarctic species (10.8 %), irregular-mosaic type of horizontal structure and relatively large overground phytomass of vascular plants (89.9 g/m2) are characterized for this zonal category. Here it is the highest value of і-diversity (b1 = 3.07). Southern and northern variants of arctic tundra are characterized by parameters distinguished from the plant cover of polar deserts zone and typical tundra subzone. These parameters are: number of syntaxa at slopes of southern exposure (11 and 8), their index of abruptness (0.36 and 0.29), number of syntaxa with diagnostic meaning of altitudinal changes (8 and 5), indexes of І-diversity (60.0 and 58.5 — dissimilarity between syntaxa, 7.9 and 8.2 — average number of species in relevй). Moreover, similar values of і-diversity (b1 = 2.30 and 2.50), zonal-geographical spectrum (wh ere total part of hypoarctic and boreal groups is smaller essentially then in typical tundra, but part of arctic group is equal to one of polar deserts) and above ground phytomass of vascular plants (83.5 g/m2and 80.1 g/m2) are peculiar to these two variants. Several vegetation indexes contribute to reveal southern and northern zonal variants. The last region is referred to the High Arctic. Also diagnostic amount of syntaxa and analytical characteristics for zonal categories of definite rank were determined. Typical syntaxa have a special significance for zonal categories of higher rank (tundra zone as whole and the subzone of arctic tundra).

Responses of Ranunculus sabinei and Papaver radicatum to removal of the moss layer in a high-arctic meadow

1987 ◽  
Vol 65 (6) ◽  
pp. 1224-1228 ◽  
Author(s):  
E. H. Sohlberg ◽  
L. C. Bliss
Keyword(s):  
Soil Moisture ◽  
Plant Growth ◽  
Vascular Plants ◽  
Vascular Plant ◽  
High Arctic ◽  
Moss Layer

Within the High Arctic, vascular plants of small size often grow in dense turfs of moss. The effect of moss removal on vascular plant growth was examined over a 2-year period for Ranunculus sabinei and Papaver radicatum. Aboveground non-repoductive parts of flowering R. sabinei were significantly (p < 0.05) larger for individuals in moss removal and moss clipped treatments than those in control plots. Similar but nonsignificant differences were found for nonflowering individuals of R. sabinei. Papaver radicatum had significantly (p < 0.05) larger aboveground, nonreproductive biomass in moss removal and replacement plots than in the moss clipped treatment and the controls. We suggest that the responses of Ranunculus sabinei to moss clipping or removal and of Papaver radicatum to moss removal and moss replacement are examples of the interaction between moss and vascular plants in relation to microsite conditions. Moss turf provides more soil moisture during drought periods as well as higher levels of nutrients. Moss removal results in warmer and more aerated soils. We interpret these results as commensalism rather than competition.

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.

Sign in / Sign up

Export Citation Format

Share Document