scholarly journals Ecophysiological response and morphological adjustment of Argania spinosa L. Skeels under contrasting climates: case study of marginal populations

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Mohamed Ait Bihi ◽  
Fatima Ain-Lhout ◽  
Abdelhakim Hatimi ◽  
Fadma Fahmi ◽  
Saida Tahrouch
Keyword(s):  
Stomatal Density ◽  
Photochemical Efficiency ◽  
Carbon Assimilation ◽  
Distribution Area ◽  
Summer Drought ◽  
The South ◽  
Marginal Populations ◽  
Southern Limit ◽  
Argania Spinosa ◽  
The North

In this paper, we investigated the seasonal physiological performance and morphological adjustment of Argania spinosa growing under contrasting climatic and biogeographic conditions.Two marginal populations were selected in the main distribution area of the species, one at the Northwest and the other one at the South-west. Trees from the North showed a Mediterranean pattern in Photosynthetic performances, exhibiting maximal carbon assimilation during spring and minimum in summer. In contrast, trees from the South showed a different pattern with maximum values recorded in winter and minimum in spring. Photochemical efficiency of PSII results evidenced the absence of damage to PSII in both sites, probably due to an efficient energy dissipation processed by carotenoid pigments. We recorded increased LMA values in the South, which improves drought resistance. Increasing stomatal length and decreasing stomatal density were registered during the drought season in both populations. A. Spinosa is sensitive to changes in the length of drought stress at its Southern limit. The scarcity of rainfall leading to persistent drought has limited the distribution of the species to the banks of dry Wadis and depressions, where it finds some water compensations during summer. In the North, the summer drought severely impacted the species carbon assimilation.

scholarly journals Global change affects differently at local scales animal populations: why Starlings still expands to the south while other temperate species go to the north?

2021 ◽  
Author(s):  
Alexandra Rodriguez ◽  
Giuseppe La Gioia ◽  
Patricia Le Quilliec ◽  
Damien Fourcy ◽  
Philippe Clergeau
Keyword(s):  
Climate Change ◽  
Global Change ◽  
Sturnus Vulgaris ◽  
European Starling ◽  
Distribution Area ◽  
The South ◽  
The North ◽  
Animal Populations ◽  
The World ◽  
Landscape Transformations

Global change, which regroups global warming, landscape transformations and other anthropic modifications of ecosystems, has effects on populations and communities and produces modifications in the expansion area of species. While some species disappear, other ones are beneficiated by the new conditions and some of them evolve in new adapted forms or leave their ancient distribution area. As climate change tends to increase the temperature in several regions of the world, some species have been seen to leave areas in equatorial regions in order to join colder areas either towards the north of the northern hemisphere or towards the south of the southern one. Many birds as have moved geographically in direction to the poles and in many cases they have anticipated their laying dates. Actually, two tit species that use to lay their eggs in a period that their fledging dates synchronize with the emerging dates of caterpillars are now evolving to reproductive in periods earlier than before the climate change. Several species are reacting like that and other ones are moving to the north in Europe for example. Nevertheless, and very curiously, European starling, Sturnus vulgaris, populations are behaving on the contrary: their laying dates are moving towards later spring and their distribution area is moving towards the south. In this study we explore and discuss about different factors that may explain this difference from other birds.

Le synclinal danien-eocene de La Mourotte (Var)

1962 ◽  
Vol S7-IV (1) ◽  
pp. 87-91 ◽  
Author(s):  
Fernand Touraine
Keyword(s):  
Upper Jurassic ◽  
The South ◽  
Northern Limit ◽  
Southern Limit ◽  
The North ◽  
Bird Eggs ◽  
Tectonic Study ◽  
Dinosaur Eggs

Abstract Results of a stratigraphic and tectonic study of the Mourotte syncline, Provence, France, divide the structure into three parts. The northern part is composed of Hauterivian littoral beds containing Danian dinosaur eggs. The Danian limestone-sandstone series disappears at La Neuve while the marly upper Danian beds continue to the extreme northern limit of the syncline. In the central part the Hauterivian wedges out, and toward its southern limit the substratum is entirely upper Jurassic. In the southern part, the Danian limestones are only visible on the northeast border. Bird eggs collected in the area assign the southern part of the syncline to the Thanetian. Overturning is less noticeable in the north, becoming acute toward the south where the syncline is tightly overturned.

Phytoplankton Succession and Primary Production in Babine Lake, British Columbia

1975 ◽  
Vol 32 (12) ◽  
pp. 2413-2427 ◽  
Author(s):  
John G. Stockner ◽  
K. R. S. Shortreed
Keyword(s):  
Primary Production ◽  
Sockeye Salmon ◽  
Mixed Layer Depth ◽  
Carbon Assimilation ◽  
Annual Production ◽  
Phosphate Limitation ◽  
The South ◽  
South Basin ◽  
The North ◽  
Principal Factors

Ten stations located in six zones (subbasins) were sampled biweekly from May to October 1973 to detect possible regional differences in production in this large, 155 km long, dystrophic lake. The spring bloom occurred in all zones while a fall bloom occurred only in Zones 5 and 6. Carbon assimilation showed two peaks in south basin zones, but only one (spring) at zones north of Topley Landing. Seasonal variation in phytoplankton numbers and volume, seston, and chlorophyll a followed a pattern similar to that noted for primary production. Mean production was 100 mg C∙m−2∙day−1 in Zones 1–4, but was 145 in Zones 5 and 6. Annual production was estimated at 25 g C∙m−2 in the north basin and 40 in the south basin. Reasons for the regional disparities are discussed, with greatest significance given to regional variations in mixed layer depth, surface inflows (loading), and basin mean depth. The development and sustainment of the autumnal bloom of Tabellaria fenestrata is thought to be one of the principal factors responsible for greater production in the south basin.An estimated 0.05 g TP∙m−2 enters the lake yearly. This can vary depending on the return of adult sockeye salmon (Oncorhynchus nerka), whose carcasses contribute up to 20% of the total. An estimated 30% is lost via the Babine River, and it is speculated that of the remaining 70%, most is lost to the sediments. Phosphate limitation is implied as a chief factor limiting primary production in the north basin stations, but not in the south basin. On the basis of total phosphorus load the lake is classed as oligotrophic, but in terms of annual production and its humic stained waters it is more correctly considered mixotrophic.

scholarly journals The Proterozoic mobile belt in the Ammassalik region, South-East Greenland (Ammassalik mobile belt): an introduction and re-appraisal

1989 ◽  
Vol 146 ◽  
pp. 5-12
Author(s):  
B Chadwick ◽  
P.R Dawes ◽  
J.C Escher ◽  
C.R.L Friend ◽  
R.P Hall ◽  
...  
Keyword(s):  
Shear Zones ◽  
Granulite Facies ◽  
Mobile Belt ◽  
The South ◽  
Southern Limit ◽  
Late Archaean ◽  
Early Proterozoic ◽  
The North ◽  
Layer Cake ◽  
Dyke Swarms

The Ammassalik mobile belt is characterised by a regional layer cake structure of tectonically interleaved sheets of quartzo-feldspathic orthogneisses and supracrustal rocks. The sheets of supracrustal rocks are most abundant in the north of the belt and they include semi-pelitic kyanite-sillimanite gneisses, graphitic schists, marble, amphibolites and local peridotite. The sheets are regarded as parts of a disrupted supracrustal sequence, here termed the Siportoq supracrustal association. Preliminary isotopic age data suggest that most of the orthogneisses are late Archaean, although some have early Proterozoic ages. The Siportoq supracrustal association has yielded an early Proterozoic age. Amphibolite dyke swarms were emplaced at various stages in the evolution of the mobile belt. The Ammassalik belt has an ill-defined northern limit marked by heterogeneous retrogression of a granulite facies terrain up to 100 km wide. Most of the belt is at amphibolite facies, with its southern limit lying to the south of the area considered here. The structure in the south is dominated by nappes and shear zones dipping NE within a wide tract of late Archaean orthogneisses intruded by amphibolite dyke swarms with relatively well preserved primary characteristics. The structure in the north is characterised by more pervasive deformation which gave rise to complex sequences of thrusting and nappe development propagating from the north. Large domes were superimposed on the nappe pile, perhaps as buoyancy phenomena. The dioritic Ammassalik Intrusive Complex (c. 1885 Ma) with its granulite facies assemblages is regarded as a late kinematic phenomenon. Major post-tectonic complexes of granite, diorite and gabbro (c. 1580 Ma) were intruded at a high level well after the close of the tectonism in the Ammassalik mobile belt.

Phytogeography of the subtribe Leipoldtiinae (Mesembryanthemaceae)

Bothalia ◽  
1987 ◽  
Vol 17 (2) ◽  
pp. 205-212 ◽  
Author(s):  
H. E. K. Hartmann
Keyword(s):  
Distribution Area ◽  
The South ◽  
Winter Rainfall ◽  
Species Frequency ◽  
The North ◽  
Centres Of Diversity ◽  
Present Distribution

An investigation of distribution and species frequency of the nine genera of the subtribe Leipoldtiinae shows that two centres of diversity can be distinguished. These coincide more or less with the 'Gariep centre’ in the north and the ’Vanrhynsdorp centre' in the south (both sensu Nordenstam 1969). Speciation seems to have occurred in both centres. The subtribe may have evolved in an arid winter rainfall area which could have been situated outside its present distribution area. The centres of distribution coincide with those observed in both subfamilies of the Mesembryanthemaceae.

scholarly journals Nutrient regimes control phytoplankton ecophysiology in the South Atlantic

2014 ◽  
Vol 11 (2) ◽  
pp. 463-479 ◽  
Author(s):  
T. J. Browning ◽  
H. A. Bouman ◽  
C. M. Moore ◽  
C. Schlosser ◽  
G. A. Tarran ◽  
...  
Keyword(s):  
Photochemical Efficiency ◽  
South Atlantic ◽  
The South ◽  
Southern Boundary ◽  
The North ◽  
Incubation Experiments ◽  
Circumpolar Current ◽  
Control Patterns ◽  
The Antarctic ◽  
Fe Addition

Abstract. Fast Repetition Rate fluorometry (FRRf) measurements of phytoplankton photophysiology from an across-basin South Atlantic cruise (as part of the GEOTRACES programme) characterised two dominant ecophysiological regimes which were interpreted on the basis of nutrient limitation. South of the South Subtropical Convergence (SSTC) in the northern sub-Antarctic sector of the Antarctic Circumpolar Current (ACC) in the Eastern Atlantic Basin, waters are characterised by elevated chlorophyll concentrations, a dominance by larger phytoplankton cells, and low apparent photochemical efficiency (Fv / Fm). Shipboard 24 h iron (Fe) addition incubation experiments confirmed that Fe stress was primarily responsible for the low Fv / Fm, with Fe addition to these waters, either within the artificial bottle additions or naturally occurring downstream enrichment from Gough Island, significantly increasing Fv / Fm values. To the north of the SSTC at the southern boundary of the South Atlantic Gyre, phytoplankton are characterised by high values of Fv / Fm which, coupled with the low macronutrient concentrations and increased presence of picocyanobacteria, are interpreted as conditions of Fe replete, balanced macronutrient-limited growth. Spatial correlation was found between Fv / Fm and Fe:nitrate ratios, supporting the suggestion that the relative supply ratios of these two nutrients can control patterns of limitation and consequently the ecophysiology of phytoplankton in subtropical gyre and ACC regimes.

scholarly journals Coexistent Heteroblastic Needles of Adult Pinus canariensis C.Sm. ex DC. in Buch Trees Differ Structurally and Physiologically

Forests ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 341
Author(s):  
Beatriz Fernández-Marín ◽  
Marcos Adrián Ruiz-Medina ◽  
José Carlos Miranda ◽  
Águeda María González-Rodríguez
Keyword(s):  
Vascular Tissue ◽  
Stomatal Density ◽  
Photochemical Efficiency ◽  
Carbon Assimilation ◽  
Pinus Canariensis ◽  
Adult Transition ◽  
Needle Anatomy ◽  
Leaf Mass Area ◽  
Adult Trees ◽  
Gap Opening

Great variation in shape and size between primary (juvenile) and secondary (adult) needles, so-called leaf-heteroblasty, occurs in several Pinus species. Most of them loss primary needles during the juvenile-to-adult transition of the tree. An exception to this is Pinus canariensis (a Canary Islands endemism) in which basal resprouting twigs of adult trees frequently wear both primary and secondary needles. Taking advantage of this extraordinary study-case-species, we conducted an exhaustive comparison of both needle types through quantitative analyses of needle anatomy, photochemical performance, gas exchange, and resistance to extreme dehydration and to extreme needle temperature. We hypothesized that primary needles would show lower investment to leaf structure but higher photosynthetical efficiency. Primary needles had less stomatal density and thicker and less wettable cuticles. In cross section, primary needles showed smaller structural fraction (e.g., percent of hypodermis, endodermis and vascular tissue) and higher fraction of photosynthetic parenchyma. Significant differences between primary and secondary needles were not found in net carbon assimilation not in their leaf mass area values. Interestingly, secondary needles showed higher electron transport rate, and they were additionally much more efficient in retaining water under severe and controlled desiccant conditions. When subjected to extreme temperatures (−10° to +50 °C), primary needles recovered better their photochemical efficiency than secondary needles, after +46° and +48 °C heat-shock treatments. Our results indicate that both needle types broaden the diversity of physiological responses against environmental constrains in basal twigs of adult P. canariensis trees. Considering that this is a fire-resistant and resprouting species, this advantage could be particularly useful after a drastic environmental change such a fire or a gap opening in the forest.

scholarly journals Le Domérien-Toarcien Inférieur De La Ride De Fert Elbir (Rides Sud-Rifaines, Maroc)

2017 ◽  
Vol 13 (36) ◽  
pp. 132
Author(s):  
Mohamed Erragragui ◽  
Aïssa Masrour ◽  
Hicham Benbaqqal ◽  
Mostafa Gretaa
Keyword(s):  
Biological Diversity ◽  
The South ◽  
Southern Limit ◽  
The North ◽  
Facies Associations ◽  
Northwestern Margin ◽  
History Of ◽  
Paleoenvironmental Evolution ◽  
The Many

The South-Rifain ridges are located at 30 Km in the North of Meknes City, they constitute the extreme southern limit of the Rifaine chain. Globally, these ridges integrate into the history of African northwestern margin evolution. Mainly, the frame of this ridge is composed of the Jurassic sedimentation. The Fert Elbir ridge, subject of this study, is among the leading reliefs in the South-Rifain ridges. Generally, in this ridge, two geological sections have been studied, in the objective to determine and to understand the history of sedimentological, bio-stratigraphical and paleoenvironmental evolution of the Jurassic sedimentary series. Essentially, it includes the carbonates and marls deposits, composed mainly by several facies and micro-facies, grouped in eight facies associations. They contain a very important biological diversity especially at the level of the middleDomerian. Paleo-environmentally, this sedimentation series was deposited in the many diversified environments, having the areas of deposit essentially very close to the coast (proximal), or located in distal position with several hundred meters from the shore.

Reconnaissance of the Central San Joaquin Valley

1941 ◽  
Vol 7 (2Part1) ◽  
pp. 123-133 ◽  
Author(s):  
Gordon W. Hewes
Keyword(s):  
San Joaquin Valley ◽  
Base Line ◽  
The South ◽  
Northern Limit ◽  
Southern Limit ◽  
Central California ◽  
The North ◽  
East And West ◽  
California Archaeology ◽  
Central San Joaquin Valley

A survey of the central San Joaquin Valley has demonstrated a threefold cultural sequence north of Stockton, upsetting the earlier view that central California archaeology lacked evidence of change; south of Tulare Lake are indications of similar cultural stratification. Before the survey the 160 miles between Stockton and Tulare Lake was known only from scattered specimens and occasional correspondence with local collectors.The area of the 1939 reconnaissance is bounded on the north by the southern limit of Schenck and Dawson's 1929 report, the Mount Diablo Base Line; on the south, by Gifford and Schenck's northern limit, the southern end of Tulare Lake; on the east and west, by the Valley drainage limits. This territory includes the basin of the second largest river in California, and was formerly occupied by the bulk of the Yokutsspeaking peoples, and by some of the Miwok and Mono.

scholarly journals Nutrient regimes control phytoplankton ecophysiology in the South Atlantic

2013 ◽  
Vol 10 (7) ◽  
pp. 11969-12008
Author(s):  
T. J. Browning ◽  
H. A. Bouman ◽  
C. M. Moore ◽  
C. Schlosser ◽  
G. A. Tarran ◽  
...  
Keyword(s):  
Photochemical Efficiency ◽  
South Atlantic ◽  
The South ◽  
Western Atlantic ◽  
Southern Boundary ◽  
The North ◽  
Circumpolar Current ◽  
Control Patterns ◽  
Chlorophyll Concentrations ◽  
Fe Addition

Abstract. Fast Repetition Rate fluorometry (FRRf) measurements of phytoplankton photophysiology from an across-basin South Atlantic cruise (as part of the GEOTRACES programme) characterized two dominant ecophysiological regimes which were interpreted on the basis of nutrient limitation. South of the South Subtropical Convergence (SSTC) in the northern sub-Antarctic sector of the Antarctic Circumpolar Current (ACC) in the Eastern Atlantic Basin, waters are characterized by elevated chlorophyll concentrations, a dominance by larger phytoplankton cells, and low apparent photochemical efficiency (Fv / Fm). Shipboard 24 h iron (Fe) addition incubation experiments confirmed that Fe stress was primarily responsible for the low Fv / Fm, with Fe addition to these waters, either within the artificial bottle additions or naturally occurring downstream enrichment from Gough Island, significantly increasing Fv / Fm values. Satellite images suggest a broader region of enhanced chlorophyll concentrations around the SSTC in the Western Atlantic relative to the Eastern Atlantic: hypothesized to be a result of higher iron supply from the South American continent. To the north of the SSTC at the southern boundary of the South Atlantic Gyre, phytoplankton are characterized by high values of Fv / Fm which, coupled with the low macronutrient concentrations and increased presence of picocyanobacteria, are interpreted as conditions of Fe replete, balanced macronutrient-limited growth. Spatial correlation was found between Fv / Fm and Fe:nitrate ratios, supporting the suggestion that the relative supply ratios of these two nutrients can control patterns of limitation and consequently the ecophysiology of phytoplankton in subtropical gyre and ACC regimes.

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