scholarly journals Floristic patterns of the neotropical forests, savannas and scrublands with Trithrinax campestris (Arecaceae) in central Argentina

2021 ◽  
Vol 2 ◽  
pp. 5-18
Author(s):  
Sebastián R. Zeballos ◽  
Marcelo R. Cabido ◽  
Juan J. Cantero ◽  
Alicia T.R. Acosta ◽  
M. Virginia Palchetti ◽  
...  

Aims: Trithrinax campestris is one of the palm species with the southernmost distribution in the Neotropics. Despite that the vegetation types in which T. campestris occurs are nowadays heavily threatened by land use and land cover changes, their floristic composition and structure are still to be documented. In order to characterize T. campestris habitats, the aim of this study was to describe the floristic composition of the vegetation types in which this palm occurs and their relationships with different environmental factors. Study area: The survey was conducted in central Argentina in an area comprising the southern extreme of the distribution of T. campestris in the following phytogeographic areas: Espinal, Lowland and Mountain Chaco. Methods: Following the Braun-Blanquet approach we collected 92 floristic relevés recording a total of 601 vascular plant species. Vegetation was classified through the ISOPAM hierarchical analysis. Bioclimatic and elevation data were related to the floristic data through the ISOMAP ordination. Remote-sensed images (Landsat TM, ETM+ and OLI) were used to characterize the fire frequency in the 92 stands. Results: Four vegetation types that differed in floristic composition and in diagnostic species were discriminated: 1.1 Celtis tala/Sida rhombifolia closed forest; 1.2 Aspidosperma quebracho-blanco/Prosopis kuntzei open forest; 2.1 Jarava pseudoichu/Vachellia caven open savanna; and 2.2 Acalypha variabilis/Nassella cordobensis scrubland. The ISOMAP ordination showed that differences in floristic composition were related to elevation, topography and climatic variables.Out of the 92 stands, only 21 showed the occurrence of fires during the period 1999–2018. Conclusions: Our results evidenced that vegetation types (forests, savannas and scrublands) comprising T. campestris developed in a wide range of environmental conditions. This is the first study that focuses on all vegetation types in which T. campestris occurs in central Argentina and it is relevant for conservation and sustainable management of the only native palm species in the flora of this part of the country. Taxonomic reference: Catálogo de las Plantas Vasculares del Cono Sur (Zuloaga et al. 2008) and its online update (http://www.darwin.edu.ar). Abbreviations: ISOMAP = isometric feature mapping; ISOPAM = isometric partitioning around medoids.

Phytotaxa ◽  
2016 ◽  
Vol 249 (1) ◽  
pp. 118 ◽  
Author(s):  
FARSHID MEMARIANI ◽  
MOHAMMAD REZA JOHARCHI ◽  
HOSSEIN AKHANI

Ghorkhod Protected Area (GPA) is located in a transitional zone among different biogeographical units in North Khorassan Province, NE Iran. The study area is mainly a mountainous region in western extensions of Khorassan-Kopet Dagh floristic province. We investigated the floristic composition, life form spectrum and phytogeography of the study area through several random collection efforts and 200 vegetation samples (reléves) in selected vegetation types during 2007–2012. A total of 663 vascular plant species belonging to 367 genera and 81 families are recorded as native and naturalized in GPA. Angiosperms and Dicots are among the most diverse plant groups. The richest plant families are Asteraceae (88 species), Poaceae (78), Lamiaceae (45), Brassicaceae (43), Fabaceae (38), and Caryophyllaceae (32). The genera Allium L. (17 species), Astragalus L. (15) and Cousinia Cass. (12) are the richest ones, however, the majority of the species belongs to oligotypic and monotypic genera. Life form spectrum of the study area is dominated by hemicryptophytes (38.9%) and therophytes (23.4%). Allium transvestiens Vved., Agropyron desertorum Schult., Helictotrichon turcomanicum Czopanov and Piptatherum latifolium (Roshev.) Nevski are recorded as new to Iran. The core flora of the area has the Irano-Turanian origin. However, the wide-range and widespread elements are also well represented in the study area. GPA is inhabited by several endemic, rare and narrow-range plant species, indicating the biodiversity importance of the study area in NE Iran.


2017 ◽  
pp. 93-118
Author(s):  
G. S. Shushpannikova ◽  
S. M. Yamalov

The present study continues a series of publications by the authors on the diversity of the herb vegetation in the floodplains of the Vychegda and Pechora rivers and their tributaries (Komi Republic). The floristic classification of the orders Molinietalia Koch 1926 and Arrhenatheretalia R. Tx. 1931 was published earlier (Shushpannikova, Yamalov, 2013, 2014). The results of classification of communities belonging to the class Phragmito–Magno-Caricetea Klika in Klika et Novák 1941 are discussed in this paper in accordance with principles of the Braun-Blanquet approach (Braun-Blanquet, 1964; Mirkin, Naumova, 1998). Analysis was based on 268 relevés made in 1981–2016. The assessment of environmental parameters was performed by ecological methods by L. G. Ramensky (Ramensky et al., 1956). Syntaxonomic diversity of the vegetation of the class Phragmito–Magno-Caricetea in the floodplain of rivers Vychegda and Pechora is presented by 3 orders (Phragmitetalia W. Koch 1926, Oenanthetalia aquaticae Hejny in Kopecky et Hejny 1965 and Magno-Caricetalia Pignatti 1953), 4 alliances (Phragmition communis W. Koch 1926, Nardosmion laevigatae Klotz et Köck 1986, Equisetion arvensis Mirkin. et Naumova in Kononov et al. 1989 emend. Taran 1995 and Magnocaricion elatae Koch 1926) and 13 associations. The communities of the class Phragmito–Magno-Caricetea, as well as the order Molinietalia of Molinio–Arrhenatheretea, are located at all levels of the floodplains and are characterized by a variety of humidification conditions. However, the communities of the class Phragmito–Magno-Caricetea are characterized by higher humidification indices (72.2–86.3) compared to meadow vegetation the order Molinietalia of the class Molinio-Arrhenatheretea of (68.8–74.4). A lot of associations, heterogeneous in their floristic composition, can be divided into 9 subassociations and 10 variants. New 4 subassociations (caricetosum vesicariae, equisetosum fluviatilis, persicaretosum amphibiae and lysimachetosum vulgaris), are included into ass. Caricetum gracilis Savich 1926. The peculiarities of the floristic composition of the above mentioned associations, as well as their distribution and ecology are discussed. The distinguished associations are well differentiated by their elevation position on the floodplains. The communities of the ass. Caricetum gracilis are located at all levels of the floodplainons; these of Agrostio stoloniferae–Equisetetum arvensis — on the highest ones; Equisetetum fluviatilis — on the lowest part of the floodplains in the riparian zone. The described communities are located on the soils with various ecological indi­cators. The distinguished associations are differentiated by the levels of humidification (65.9–89.9), mean figures — 70.3–86.3. The communities of the ass. Agrostio stoloniferae–Equisetetum arvensis occupy the driest sites (65.9–72.9); these of associations ­Equisetetum fluviatilis and Nardosmietum laevigatae — the wettest ones (80.7–87.8). The ass. Caricetum aquatilis has a wide range of humidification (72.7–89.9). The variability of humidification varies from alternating to high values (6.4–12.0). The ­greatest differences in humidification are experienced by the communities of the ass. Caricetum gracilis (5.5–12.0). Тhe communities of the ass. Agrostio stoloniferae–Equisetetum arvensis occupy the richest (10.5–15.0) and alluvial soils (4.0–5.0). They are located on the low level in the riverine and middle zone of the floodplain and are formed by annual flooding on alluvial deposits. The distinguished associations are differentiated by pH (3.0–8.0), mean figures — 4.5–7.0. The communities of the associations Caricetum juncellae, Caricetum gracilis and Caricetum acutae–rostratae are located on the most acidic soil; these of the ass. Equisetetum fluviatilis — on the neutral ones. The associations are distributed by the scale of pasture digression in range 2.5–4.5, mean figures — 3.0–3.9. The communities are used for hay-making. The question of the boundary between the meadow vegetation, lowland swamp and semi-aquatic vegetation remains unsolved. The communities of the class Phragmito–Magno-Caricetea described in this paper belongs to meadows. Ass. Nardosmietum laevigatae (previously referred to the class Galio-Urticetea Pass. 1967) is included into the order Phragmitetalia W. Koch 1926. The communities of the ass. Agrostio stoloniferae–Equisetetum arvensis have a mesophilic species composition and low moisture values, so they represent a transition between the class Molinio-Arrhenatheretea order Molinietalia and class Phragmito–Magno-Caricetea. A comparison of species composition of the syntaxa in Komi Republic and that in other regions of the Eastern Europe and the Asian part of Russia showed that the semiaquatic communities of the Komi Republic have low species diversity. It is less than 16 species on sample plot. The richest are communities of the associations Caricetum gracilis and Carici acutae–Phalaroidetum arundinaceae. 101 vascular plant species are recorded in 268 geobotanical relevés of the class Phragmito–Magno-Caricetea. The aboveground phytomass varies from 30–80 g/m2 (Agrostio stoloniferae–Equisetetum arvensis) to 420 г/м2 (Phalaroidetum arundinaceae).


2017 ◽  
pp. 21 ◽  
Author(s):  
Silvia H. Salas-Morales ◽  
Alfredo Saynes-Vásquez ◽  
Leo Schibli

The Zimatan region of Oaxaca is characterized by the occurrence of several vegetation types and a large floristic diversity, primarily due to the large elevational range that it encompasses (from sea level to 2,580 m). In 1991 this region was proposed as a high-priority area for conservation in Oaxaca State, largely due to its extensive, well-preserved tracts of tropical dry forest. Nonetheless, little biological information is available for this area. In 1997 we initiated a series of studies aimed at supporting the conservation of the Zimatan region. Here we present floristic data based on 8,063 original botanical collections. The list includes 1,384 vascular plant species, distributed among 668 genera and 144 families. These collections make of the Zimatan region one of the most comprehensively collected areas and most diverse on the Mexican Pacific coast, along with the Chamela Biological Station in Jalisco State.


2014 ◽  
Vol 23 (2) ◽  
pp. 234 ◽  
Author(s):  
Ellis Q. Margolis

Piñon–juniper (PJ) fire regimes are generally characterised as infrequent high-severity. However, PJ ecosystems vary across a large geographic and bio-climatic range and little is known about one of the principal PJ functional types, PJ savannas. It is logical that (1) grass in PJ savannas could support frequent, low-severity fire and (2) exclusion of frequent fire could explain increased tree density in PJ savannas. To assess these hypotheses I used dendroecological methods to reconstruct fire history and forest structure in a PJ-dominated savanna. Evidence of high-severity fire was not observed. From 112 fire-scarred trees I reconstructed 87 fire years (1547–1899). Mean fire interval was 7.8 years for fires recorded at ≥2 sites. Tree establishment was negatively correlated with fire frequency (r=–0.74) and peak PJ establishment was synchronous with dry (unfavourable) conditions and a regime shift (decline) in fire frequency in the late 1800s. The collapse of the grass-fuelled, frequent, surface fire regime in this PJ savanna was likely the primary driver of current high tree density (mean=881treesha–1) that is >600% of the historical estimate. Variability in bio-climatic conditions likely drive variability in fire regimes across the wide range of PJ ecosystems.


2010 ◽  
Vol 23 (3) ◽  
pp. 185 ◽  
Author(s):  
Ulf Swenson ◽  
Jérôme Munzinger

Pycnandra is a genus of Sapotaceae (Chrysophylloideae), restricted to New Caledonia, and includes ~60 species. The genus is a member of the monophyletic Niemeyera complex of Australia and New Caledonia and it is characterised by the lack of staminodes and a fruit containing a single seed, plano-convex cotyledons and absence of endosperm. In New Caledonia, several segregate genera have been recognised, but weak cladistic support for these groups and homoplasious morphology renders a narrow generic concept untenable. Instead, a broad generic circumscription of Pycnandra with an infrageneric classification recognising the subgenera Achradotypus, Leptostylis, Pycnandra, Sebertia and Trouettia results in a stable nomenclature. Here we revise Pycnandra subg. Achradotypus that includes 14 species, of which five (P. belepensis, P. blaffartii, P. bracteolata, P. glabella, and P. ouaiemensis) are described as new. Members of subg. Achradotypus are distinguished from other subgenera on the basis of a character combination of two stamens opposite each corolla lobe (except P. litseiflora), glabrous leaves (except P. belepensis and P. decandra), a distinctive reticulate tertiary leaf venation (except P. comptonii), and sepal-like bracts that often are borne along the pedicel. All species are restricted to Grande Terre except for P. decandra, whose distribution also extends to nearby Art Island (Belep Islands), and P. belepensis, which is endemic to that same island. The members grow in a wide range of vegetation types from dry maquis to humid forest, from sea level to the highest mountain massif, and on ultramafic soils to schist and greywacke (not limestone). Because of past and present threats such as mining, logging and fire, preliminary IUCN Red List assessments are provided for all species. Five taxa (P. chartacea, P. decandra subsp. decandra, P. glabella, P. litseiflora, and P. neocaledonica) are proposed the IUCN status Endangered, and P. belepensis and P. ouaiemensis are proposed to be Critically Endangered. We suggest that some locations where these species occur should be given protection in the form of nature reserves.


2011 ◽  
Vol 20 (4) ◽  
pp. 540 ◽  
Author(s):  
T. G. O'Connor ◽  
C. M. Mulqueeny ◽  
P. S. Goodman

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.


2016 ◽  
Vol 3 (2) ◽  
pp. 33-47
Author(s):  
Gazi Mosharof Hossain ◽  
ABM Enayet Hossain

Effect of exotic tree plantation on floristic composition and phytodiversity status of Rema-Kalenga wildlife sanctuary of Bangladesh was studied. A total of 309 vascular plant species under 245 genera belonging to 83 families were found to constitute the vascular flora of the studied area. The maximum number of species (298) with the highest Shannon-Weiner diversity index value (3.882±0.090) was recorded from natural forest, which was followed by 194 and 165 plant species with 3.441±0.205 and 3.398±0.103 diversity index values recorded from Tectona and Acacia plantation sites respectively. The minimum number of plant species (142) with the lowest diversity index value (2.999±0.152) was recorded from Eucalyptus plantation site. The collected data on the selected forest sites of Rema-Kalenga wildlife sanctuary showed the trends of gradual decrease in floristic composition and phytodivesity status of three plantation sites (Tectona to Acacia to Eucalyptus) in respect to natural forest, which indicated that exotic tree plantations might have negative impact on floristic composition and phytodiversity of this semi-tropical forest area and the fast-growing exotic tree plantation of Acacia and Eucalyptus should be avoided for sustainable development of Rema-Kalenga wildlife sanctuary.Jahangirnagar University J. Biol. Sci. 3(2): 33-47, 2014 (December)


2017 ◽  
pp. 43
Author(s):  
Guadalupe Cornejo-Tenorio ◽  
Alejandro Casas ◽  
Berenice Farfán ◽  
José Luis Villaseñor ◽  
Guillermo Ibarra-Manríquez

A study of the flora and vegetation physiognomy was conducted at the core zones of the Monarch Butterfly Biosphere Reserve, in the states of México and Michoacán. Collection of plant specimens was carried out du ring one year of field work and this activity was supplemented by a review of voucher specimens previously collected in the area and deposited at the Mexican herbaria IEB, EBUM, and MEXU. A total of 423 vascular plant species including 32 infraespecific taxa and grouped in 86 families and 244 genera were identified, Families with the largest species richness were Asteraceae (103), Lamiaceae (21), Fabaceae (17), and Scrophulariaceae (17).The most speciose genera were Salvia (13), Stevia (8), and Ageratina (7). Mexican endemic species comprised 135 (31.9%) species, which included 13 infrae spec ific taxa; 40 of these species belong to Asteraceae. Herbs were represented by 326 species, followed by shrubs (5 1) and trees (33). The main vegetation types recognized were coniferous forest (including combinations of fir, pine, and oak forests), cloud forest, anthropogenic grass land, and Quercus forest.


2014 ◽  
Vol 70 (1) ◽  
pp. 47-60 ◽  
Author(s):  
E V. J. Cohn ◽  
B. Tokarska-Guzik ◽  
L. C. Trueman ◽  
G. Woźniak

This paper demonstrates the flora, plant communities and substrates of an old solvay process spoil tip in Upper Silesia, Poland. In an area of 15 000 m<sup>2</sup> there are growing 136 vascular plant species. The flora is characterised by the preponderance of Asteraceae - species and long-lived perennial herbs, many of them coming from meadows and grasslands. Ninety-five percent of species are apophytes despite the anthropogenic origin of the site. A majority of species are associated with moderately dry, base-rich soils with low or moderate levels of nitrogen. The site is shown to be an important refuge for some protected species, montane species and other elements uncommon in the local flora. An analysis of a series of samples used a methodology based on the assessment of percentage cover of particular species and multivariate analysis based on TWINSPAN. Both suggested a relatively high overall similarity between the samples with minor variations associated with moister substrates.Elemental analysis and pH determinations of soil samples associated with the relevés revealed a narrow range of pH and an absence of any strong concentrations of heavy metals. A redundancy analysis of the soil-plant relationships suggested that the strongest trend of differentiation was most closely associated with a phosphate gradient, and the next strongest was pH and possibly waterlogging. The most species-rich vegetation was associated with low phosphate and high pH levels. The results could be interpreted to suggest that processes of soil development and plant succession are slow but nevertheless perceptible, with implications for future loss of diversity. The vegetation constitutes an assemblage essentially of one type showing only weak relationships with described vegetation types such as <em>Molinio-Arrhenatheretea</em> meadow, <em>Festuco-Brometea</em> grassland and <em>Caricetalia davallianae</em> mire. The results also suggest that the vegetation of the site is of considerable value for nature conservation. The site should be protected and be the subject of further research.


PhytoKeys ◽  
2018 ◽  
Vol 113 ◽  
pp. 1-31 ◽  
Author(s):  
David J. Goyder ◽  
Nigel Barker ◽  
Stoffel P. Bester ◽  
Arnold Frisby ◽  
Matt Janks ◽  
...  

This paper aims to provide a baseline for conservation planning by documenting patterns of plant diversity and vegetation in the upper catchment of the Cuito River. 417 species are recorded from this region. Nine of these are species potentially new to science. Ten species are newly recorded from Angola, with an additional species only recorded previously within Angola from the northern enclave of Cabinda. The 108 new provincial records for Moxico clearly indicate the lack of collections from Angola’s largest province. We note the existence of extensive peat deposits in the Cuito river system for the first time and suggest that one of Barbosa’s vegetation types in the area needs to be reassessed.


Sign in / Sign up

Export Citation Format

Share Document