scholarly journals Estructura y composición florística del Cerrado en el Parque Nacional Noel Kempff Mercado, Santa Cruz, Bolivia

2017 ◽  
pp. 25
Author(s):  
Bonifacio Mostacedo-C. ◽  
Thimoty J. Killeen

We studied the structure and floristic composition of the Cerrado vegetation in two sites at the Parque Nacional "Noel Kempff Mercado", Santa Cruz, Bolivia. The results indicated that the sites are located within two different types of Cerrado communities: 1) cerrado and, 2) cerradao. The lower stratum (50 cm) was dominated by grasses, while higher strata were dominated by shrubs and sub-shrubs in the cerrado, and by trees in the cerradao. We founded 41 families, 90 genera, and 112 species in the cerrado, and 37 families, 39 genera and 106 species in the cerradao. For both sites, the plant families with greater coverage and species richness were: Gramineae (29 species, 51 % cover), Leguminosae (23 species, 4.8-5. 7% cover) and Guttiferae (3 species, 1-20% cover). Other important families were: Myrtaceae, Rubiaceae, Euphorbiaceae and Melastomataceae, with 7,6 species; 4,6 species; 8, 2 species; 2, 6 species for cerrado and cerradao, respectively. Herbs are the most important for the number of species, followed by grasses and shrubs in the cerrado and by shrubs, followed by herbs and grasses in the cerradao. Floristic similarity between the two communities was relatively low (39% according to Sorensen index).

Rodriguésia ◽  
2011 ◽  
Vol 62 (1) ◽  
pp. 139-152 ◽  
Author(s):  
Rafael Augusto Xavier Borges ◽  
Marco Antônio Alves Carneiro ◽  
Pedro Lage Viana

Abstract The variation in the species richness of herbaceous plants along an altitudinal gradient was analyzed in the Serra do Ouro Branco and Serra do Ribeiro, in the townships of Ouro Branco and Ouro Preto, respectively. Plant similarity between both serras was also assessed. Twenty spots were sampled along a 440 m (1105 m to 1545 m) altitudinal range; at each site, herbs were collected within ten 1 m2 plots, totaling 200 m2. We found 101 species distributed in 59 genera and 25 families. The richest plant families in Serra do Ouro Branco were Poaceae (22 spp.), Asteraceae (14 spp.) and Cyperaceae (10 spp.), while in Serra do Ribeiro, they were Poaceae (17 spp.), Cyperaceae (12 spp.) and Asteraceae (8 spp.). Variation between the number of species and altitude was not significant. The higher number of species in Serra do Ouro Branco may be due to different local environmental factors and to the occurrence of grazing and fires. The serras presented a high similarity value (J = 0.44), but cluster and ordination analysis indicated the formation of two distinct groups, reflecting the importance of local factors to determine the floristic composition of neighboring areas of campos rupestres.


2007 ◽  
Vol 29 (2) ◽  
pp. 181 ◽  
Author(s):  
L. I. López-Olmedo ◽  
J. A. Meave ◽  
E. A. Pérez-García

The magnitude of the biological differentiation between natural savannas and pastures (anthropogenic grasslands) coexisting in a single landscape, in terms of their floristic composition and community structure, was studied in the Nizanda region, Isthmus of Tehuantepec, Oaxaca State, southern Mexico. Vegetation samples of 15 m2 each were taken at 20 savanna and 11 pasture sites. Cover- and species richness-based diversity and dominance indices were calculated. Geomorphological and edaphic characteristics were also compared. Savannas generally occurred in hill summits with very shallow and stony, discontinuous and acidic soils; contrastingly, pastures were located in piedmonts and floodplains, with more neutral and less stony soils. Savanna sites differed from pasture sites in species richness and Shannon diversity. They did not differ in Simpson dominance index, but the identity of the dominant species was different in each community: Trachypogon spicatus (L.f.) Kuntze in savanna and Megathyrsus maximus (Jacq.) B.K.Simon et S.W.L.Jacobs in pasture. A low species-level similarity (Sørensen Index) was observed between them (8.2%), and genus-level similarity was only slightly higher (27.1%). The magnitude of the biological differentiation in both community floristics and structure between these two grass-dominated communities was larger than anticipated. Current management of savannas as pasture lands may potentially trigger a severe deterioration process involving both the landscape and its plant components.


Bothalia ◽  
1999 ◽  
Vol 29 (1) ◽  
pp. 119-137 ◽  
Author(s):  
D. J. Mcdonald

The flora of the southern Langeberg is rich, w ith 1 228 species and intraspecific taxa (referred to collectively as species) recorded in 361 genera and 105 families. An analysis of the montane flora of the southern Langeberg. Western Cape, South Africa based on an annotated checklist shows that the Asteraceae has the highest number of species per familv (167) and the genus  Erica has the most infrageneric taxa per genus (130) as well as the most endemic species (51). One endemic monotypic family, the Geissolomataceae, two endemic genera Geissoloma and Langebergia (Asteraceae) and a total of 167 endemic species are found on the southern Langeberg The plant families of the southern Langeberg flora are ranked according to species-richness of the families and compared with floras of other areas (mainly montane) in the Fynbos Biome and marginally to the east of this biome (the Amatole Mountains). The greatest similarity of ranking is evident betw een the plant families of the southern Langeberg and those of the Cape Hangklip Area.


Author(s):  
Misganaw Meragiaw ◽  
Zerihun Woldu ◽  
Vegard Martinsen ◽  
Bal R. Singh

AbstractDry evergreen montane forests in Ethiopia are severely threatened. The status of species composition and structure of forest vegetation are important indicators to understand the trends of threats on local plant communities. In the present study, we examined the floristic composition and structure of the Kibate Forest, Wonchi Highland, Ethiopia along environmental gradients. Sixty-six (30 m × 30 m) plots were established every 100 m interval along altitudinal gradients (2811‒3073 m a.s.l.) in five transect lines for vegetation and environmental data collection. In total, 125 vascular plant species belonging to 104 genera and 52 families were identified. Eighteen species (14%) were endemic to Ethiopia and Eritrea. The two most dominant families, Asteraceae (29 species) and Lamiaceae (eight species) accounted for 30% of the total number of species. The highest number of species (54%) was herbs. Four major community types (viz., Olinia rochetiana-Myrsine melanophloeos, Ilex mitis-Galiniera saxifraga, Erica arborea-Protea gaguedi, and Hagenia abyssinica-Juniperus procera) were identified. The highest species richness, evenness, diversity, and importance value index were in community types 2 and 4. About 82% of the species and all endemic taxa except five were recorded in these two community types. The most dominant woody species were O. rochetiana, E. arborea, Olea europaea subsp. cuspidata, Myrica salicifolia, I. mitis var. mitis, and H. abyssinica with different patterns of population structure. The results show that there was a weak correlation between species richness and altitude. Our findings confirm that environmental variables both with interactions (such as altitude) and without interactions (such as livestock grazing) significantly (p < 0.05) affect species richness. Anthropogenic activities and overgrazing by livestock appear to be the main threat in community types 2 and 3. Urgent management practices and conservation measures such as prohibiting forest clearing and overgrazing and planting indigenous trees through community participation should be considered in community types that are rich in endemic species but are highly threatened.


2017 ◽  
Vol 63 (2) ◽  
pp. 8-16 ◽  
Author(s):  
Corrado Battisti ◽  
Marco Giardini ◽  
Francesca Marini ◽  
Lorena Di Rocco ◽  
Giuseppe Dodaro ◽  
...  

We reported a study on breeding birds occurring inside an 80 m-deep karst sinkhole, with the characterization of the assemblages recorded along its semi-vertical slopes from the upper edge until the bottom. The internal sides of the sinkhole have been vertically subdivided in four belts about 20 m high. The highest belt (at the upper edge of the cenote) showed the highest values in mean number of bird detections, mean and normalized species richness, and Shannon diversity index. The averaged values of number of detections and species richness significantly differ among belts. Species turnover (Cody’s β-diversity) was maximum between the highest belts. Whittaker plots showed a marked difference among assemblages shaping from broken-stick model to geometric series, and explicited a spatial progressive stress with a disruption in evenness towards the deepest belts. Bird assemblages evidenced a nested subset structure with deeper belts containing successive subsets of the species occurring in the upper belts. We hypothesize that, at least during the daytime in breeding season, the observed non-random distribution of species along the vertical stratification is likely due to (i) the progressive simplification both of the floristic composition and vegetation structure, and (ii) the paucity of sunlight as resources from the upper edge to the inner side of the cenote.


2016 ◽  
Vol 51 (8) ◽  
pp. 958-966 ◽  
Author(s):  
Anderson Pedro Bernardina Batista ◽  
José Márcio de Mello ◽  
Marcel Régis Raimundo ◽  
Henrique Ferraço Scolforo ◽  
Aliny Aparecida dos Reis ◽  
...  

Abstract: The objective of this work was to analyze the spatial distribution and the behavior of species richness and diversity in a shrub savanna fragment, in 2003 and 2014, using ordinary kriging, in the state of Minas Gerais, Brazil. In both evaluation years, the measurements were performed in a fragment with 236.85 hectares, in which individual trees were measured and identified across 40 plots (1,000 m2). Species richness was determined by the total number of species in each plot, and diversity by the Shannon diversity index. For the variogram study, spatial models were fitted and selected. Then, ordinary kriging was applied and the spatial distribution of the assessed variables was described. A strong spatial dependence was observed between species richness and diversity by the Shannon diversity index (<25% spatial dependence degree). Areas of low and high species diversity and richness were found in the shrub savanna fragment. Spatial distribution behavior shows relative stability regarding the number of species and the Shannon diversity index in the evaluated years.


2015 ◽  
Vol 75 (1) ◽  
pp. 114-124 ◽  
Author(s):  
M. Rocha ◽  
CC. Santos Júnior ◽  
GA. Damasceno-Júnior ◽  
VJ. Pott ◽  
A. Pott

The rhizomatous Cyperus giganteus, abundant in the Pantanal wetland, can dominate extense floodable areas as monodominant communities. The Jacadigo lake has a large area of C. giganteus, where we performed an evaluation on community structure during two months in 2010, before it was hit by a wildfire which top-killed the vegetation, compared to ten months post-fire. We utilized 40 plots of 1m × 1m, along permanent trails, assessing two strata: the upper, near the inflorescence of adult plants, and the lower, close to the water level. Our results show that fire does not affect dominance of C. giganteus, as it maintained the same cover as before fire; species richness is not much altered either - 28 before fire and 34 thereafter. Fire changed the floristic composition, due to the annual variation of species and the ability of some plants to colonize gaps and to regrow after fire from underground organs and seeds. The stratification of the vegetation with characteristic species of upper and lower strata was similar after fire.


2002 ◽  
Vol 32 (2) ◽  
pp. 277-277 ◽  
Author(s):  
João Olegário Pereira de CARVALHO

Changes in the floristic composition over an eight-year period in a logged area at the Tapajós National Forest in Brazilian Amazonia arc discussed. Two treatments of different intensities of logging were compared with an undisturbed (control) forest. Data were collected from permanent sample-plots. The effects of logging on floristic composition were stronger in the more heavily logged treatment. The number of species decreased immediately after logging, but started to increase before the fifth year after logging and was higher at the end of the study period than before logging. The more heavily logged plots responded more to disturbances, as judged by the increase in the number of species during the period after logging. This forest appears to recover its initial floristic composition after disturbance without intervention.


2014 ◽  
Vol 14 (1) ◽  
Author(s):  
Macielle Macedo Coelho ◽  
André Márcio Amorim

The aim of this study is to survey the angiosperms of two montane forest remnants in the southern Bahia, Brazil: Corcovado (SCO) and Pedra Lascada (SPL). Both fragments are located in the municipality of Almadina and Barro Preto, respectively, and are 18 km distant from each other. We sampled 899 species of angiosperms distributed in 437 genera and 116 families. The SCO was the richest area with 678 species, distributed in 367 genera and 100 families. SPL showed 466 species in 269 genera and 88 families. The percentage of species identified was 85.8% and of this total, 37.7% are endemic to the Atlantic Forest, 11.2% are endemic to southern Bahia and northern Espírito Santo and 7% are disjunct between the Atlantic Forest and Amazon. The remaining percentages (44.3%) were of species widely distributed. The richest families in the two areas were Orchidaceae (10%), Rubiaceae (7%), Bromeliaceae (5.5%), Melastomataceae (4.2%) and Poaceae (4%). The richest genera were Psychotria (2%),Piper (1.8%), Ocotea (1.6%),Vriesea (1.5%) and Peperomia (1.4%). More than half of the recorded species showed non-arboreal habit, regarding life forms documented. That comes against the assertion that many authors in the tropical forests, where species richness in angiosperms is expected for non-woody species, especially in montane forests. Twelve species have been identified as new, but seven others already described from collections previously obtained in these two areas. Orchidaceae, Rubiaceae, Poaceae and Bromeliaceae showed significant richness in this study these families are commonly reported as the richest in other inventories in the Atlantic Forest in southern Bahia reinforcing their importance to the regional flora. The high levels of richness, endemism, and the growing numbers of new taxonomic discoveries from the SPL and SCO sites indicate the biological importance of these two forest remnants. The implementation of parks or other protected environmental reserves would be essential to the conservation of its species.


2009 ◽  
Vol 69 (2) ◽  
pp. 231-240 ◽  
Author(s):  
MV. Cianciaruso ◽  
MA. Batalha

In South America, the largest seasonal savanna region is the Brazilian cerrado. Our aim was to study temporal changes in some community descriptors, such as floristic composition, richness, species density, plant density, and cylindrical volume, in a seasonal cerrado, comparing it to a nearby hyperseasonal cerrado. In four different seasons, we placed randomly ten 1 m² quadrats in each vegetation form and sampled all the vascular plants. Seasonal changes in floristic composition, species density, and plant density were less pronounced in the seasonal than in the hyperseasonal cerrado. Floristic similarity between the vegetation forms was lower when the hyperseasonal cerrado was waterlogged. Richness and species density were higher in the seasonal cerrado, which reached its biomass peak at mid rainy season. The hyperseasonal cerrado, in turn, reached its biomass peak at early rainy season and, despite the waterlogging, maintained it until late rainy season. In the hyperseasonal cerrado, waterlogging acts as an environmental filter restricting the number of cerrado species able to withstand it. The seasonal cerrado community was more stable than the hyperseasonal one. Our results corroborated the idea that changes in the environmental filters will affect floristic composition and community structure in savannas.


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