Effects of Dominant Trees and Anthropogenic Disturbances on Species Richness and Floristic Composition of Secondary Communities in Southern Poland

1997 ◽  
Vol 34 (4) ◽  
pp. 861 ◽  
Author(s):  
Zbigniew Dzwonko ◽  
Stefania Loster
1992 ◽  
Vol 19 (2) ◽  
pp. 195 ◽  
Author(s):  
Zbigniew Dzwonko ◽  
Stefania Loster

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.


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.


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.


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.


2017 ◽  
Vol 65 (3) ◽  
pp. 1215 ◽  
Author(s):  
Ana Carolina Souza Brito ◽  
Alexandre Ferraro ◽  
Robyn J. Burnham ◽  
Ângela Lúcia Bagnatori Sartori ◽  
Vivian Almeida Assunção

In the Parana basin, the Serra de Maracaju juxtaposes the Seasonal Dry Forest and the cerradão (a phytophysiognomy of Cerrado), two distinct vegetation types that differ in canopy height, tree density, and composition of the understory. In the same way, these differences may be reflected in the composition of climbing plant species found in these two forest types. Thus, in this study we compared the climbing species in two forest fragments of Serra de Maracaju to understand: (1) Are species richness and floristic composition of climbing plants similar in cerradão and seasonal deciduous forest?, (2) What degree of floristic compositional difference exists between the two vegetation types?, (3) Do the two vegetation types differ significantly in climbing mechanisms, life forms, and dispersal syndromes represented among climbing species? For this, we established and sampled four plots per forest type over 24 months. Species were identified and each one classified, based on three discrete traits. Proportional differences were analyzed using chi-square tests. Our results showed that species richness and floristic composition of climbing plants in the cerradão and the seasonal deciduous forest were not similar. Climber species richness in cerradão was 37 while in the seasonal deciduous forest it was 31; they share only 13 species. Four families, Dioscoreaceae, Fabaceae, Malpighiaceae, and Sapindaceae, included over 60% of the climbing species. The morphological traits most common in both forest types were herbaceous life form, apical twining mechanism, and wind dispersal. Dioscoreaceae was found to be the dominant family, but is the first time to be reported for this condition in Brazil. Bignoniaceae and Passifloraceae ocurred only in the cerradão, and Asteraceae and Combretaceae in the seasonal deciduous forest; some species were found exclusively in a type of forest. Floristic composition of the cerradão and seasonal deciduous forest fragments were substantially different, in spite of physical proximity. However, their climbing species are not statistically distinct in morphological characteristics, possibly due to uniform climatic conditions and the similarity of species because of a shared ancestry (similar families).


2020 ◽  
Vol 38 ◽  
Author(s):  
I. QUINTERO-PERTÚZ ◽  
E. CARBONÓ-DELAHOZ ◽  
A. JARMA-OROZCO

ABSTRACT: This study was conducted to determine the richness and composition of weed communities associated with banana plantations in Magdalena department, Colombia. Between September 2016 and May 2017, a total of 164 hectares were assessed over four agroecological zones (Alta, Media, Baja and Norte); in each zone, three representative farms were selected where, through zigzag paths, botanical collections were made in cultivated lots. Information on life cycle, growth habit and origin of each species was included. The floristic composition was represented by 204 species distributed among 143 genera and 54 families. Poaceae, with 31 species, was the family with the highest species richness, followed by Fabaceae (12) and Asteraceae (11). From the total species recorded, 113 are perennial (55%) and 91 are annual (45%); 141 species are herbaceous (68%), 38 are climbers (20%), and 25 are arboreal or shrubby (12%). Native species predominate over introduced species. The species richness does not differ significantly between the sampling zones, but the weed community composition does. The presence of common species reported as important weeds worldwide was recorded in the four zones. However, some species were recorded in only one of the zones, generating a differential composition pattern. Comparison with local inventories showed changes in the composition of the weed complex over time. The presence of various species not previously considered weeds in the banana crops of this region is highlighted.


Zootaxa ◽  
2019 ◽  
Vol 4656 (2) ◽  
pp. 243-273
Author(s):  
ARTURO ARELLANO-COVARRUBIAS ◽  
MARYSOL TRUJANO-ORTEGA ◽  
ARMANDO LUIS-MARTÍNEZ ◽  
MERCEDES LUNA-REYES ◽  
JORGE LLORENTE-BOUSQUETS

Riodinidae are one of the most diverse families of Lepidoptera, mainly in the Neotropical region; however, their biology, ethology, taxonomy, systematics, and biogeography are poorly known. In Mexico, the regional and local distributions of the family are still incomplete. We review the distributional data of the genus Lasaia Bates (Lepidoptera: Riodinidae), based on records from four national and seven international collections. We record five species and seven subspecies in Mexico, with 2722 records, distributed in 314 localities of 24 states. The states with higher species richness are Chiapas, Oaxaca, and Veracruz; also, the genus was recorded in 11 of the 14 biogeographical provinces of Mexico. The tropical semi-deciduous and deciduous forests, below of 1000 m a.s.l., contain most of the diversity of Lasaia. Historical data are crucial for the study of local and regional diversity and ecological patterns at large temporal scales. Data presented here show the morphological and ecological variation of Lasaia over the last 80 years, mostly from the XX century when anthropogenic disturbances were intensified. This kind of studies is the first step in recording the historical distribution of these taxa, which will lead to more complex analyses on distribution range shifts, their causes and consequences. 


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