scholarly journals Do habitat fragmentation and fire influence variation of plant species composition, structure and diversity within three regional ecosystems on the Sunshine Coast, Queensland, Australia?

2014 ◽  
Vol 62 (1) ◽  
pp. 36 ◽  
Author(s):  
Rohan Etherington ◽  
Alison Shapcott
Keyword(s):  
Species Richness ◽  
Habitat Fragmentation ◽  
Forest Ecosystem ◽  
Patch Size ◽  
Floristic Composition ◽  
Vegetation Types ◽  
Time Since Fire ◽  
Fixed Sample ◽  
Open Forest ◽  
Composition Structure

Habitat fragmentation is considered to be one of the greatest threats to biodiversity. Species richness is predicted to decrease with decreasing patch size and increasing isolation, and this has been shown in some ecosystems. However, few studies have specifically investigated the effects of fragmentation on specific vegetation types, or compared different vegetation types within the same region. In this study, we assessed the influence of habitat fragmentation and time since fire on the floristic composition, structure and diversity of three ecosystems with varying fire proneness within the Sunshine Coast region. This study found that the tall-open forest ecosystem (RE 12.9-10.14) had higher overall species richness within fixed sample areas used for this study than did either open forest (RE 12.5.3) or gallery rainforest (RE 12.3.1), because it was composed of species typical of each of these ecosystem types. Open forest species richness was found mostly in the lower stratum, whereas gallery rainforest diversity was found in the upper stratum. Species richness decreased with increasing isolation in the open forest ecosystem where seeds are mostly abiotically dispersed. However, this study did not find strong evidence for reduced species richness within smaller patches in any ecosystem type studied; instead, finding species richness decreased with increasing patch size in the open forest ecosystem. Overall, across ecosystems, time since fire affected vegetation structure, but in fire-prone ecosystems, time since fire was not a determinant of species richness within the sites studied.

scholarly journals Liana species composition differs, in spite of trait similarities, in two adjacent forest types in Central Brazil

2017 ◽  
Vol 65 (3) ◽  
pp. 1215 ◽  
Author(s):  
Ana Carolina Souza Brito ◽  
Alexandre Ferraro ◽  
Robyn J. Burnham ◽  
Ângela Lúcia Bagnatori Sartori ◽  
Vivian Almeida Assunção
Keyword(s):  
Species Richness ◽  
Deciduous Forest ◽  
Morphological Characteristics ◽  
Floristic Composition ◽  
Dry Forest ◽  
Forest Fragments ◽  
Vegetation Types ◽  
Forest Types ◽  
Climbing Plants ◽  
Dispersal Syndromes

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).

A comparison of Mopaneveld vegetation in South Africa, Namibia and Zimbabwe

Bothalia ◽  
2003 ◽  
Vol 33 (1) ◽  
pp. 121-134 ◽  
Author(s):  
F. Siebert ◽  
G. J. Bredenkamp ◽  
S. J. Siebert
Keyword(s):  
South Africa ◽  
Species Richness ◽  
Plant Communities ◽  
Environmental Gradients ◽  
Floristic Composition ◽  
Alpha Diversity ◽  
Environmental Data ◽  
Annual Rainfall ◽  
Vegetation Types ◽  
Rainfall Events

Data from fifteen phytosociological studies were merged and classified to describe and compare the vegetation of geo­graphically separated and climatically different Mopanev eld types in South Africa. Namibia and Zimbabw e. Seven v egetation types and ten major plant communities were identified using TW INSPAN. Vegetation types were separated according to geo­graphical regions. There were significant floristic affinities even though there w ere geological and climatic differences between the regions. Plant communities were described according to vegetation structure, habitat and floristic composition. Although environmental data were not adequate for a detailed ordination. DECORANA reflected the distribution of vegetation types and major plant communities along environmental gradients. Limitations of large phytosociological syntheses were also addressed. Species richness (alpha diversity) was calculated for each geographical region. The Musina (Messina) region north of the Soutpansberg. South Africa, has the highest species richness, and Kaokoland. Namibia, the lowest Due to irregular annual rainfall patterns in semi-arid Mopaneveld, it is suggested that variance in species richness is associated with temporal vegeta­tion states induced by rainfall events. Species richness of Mopaneveld was further compared w ith other sav anna types.

scholarly journals Distribution Patterns and Floristic Analysis of the Colymbada Tauromenitana (Guss.) Holub Populations in Sicily (Italy)

2014 ◽  
Vol 73 (2) ◽  
pp. 385-410 ◽  
Author(s):  
Saverio Sciandrello ◽  
Sonia D’agostino
Keyword(s):  
Species Richness ◽  
Floristic Composition ◽  
Distribution Patterns ◽  
Vegetation Types ◽  
Ecological Data ◽  
Risk Status ◽  
The Third ◽  
Floristic Analysis ◽  
Components Analysis ◽  
Main Factor

AbstractColymbada tauromenitana(Guss.) Holub (Asteraceae) is a rare paleoendem-ic, chasmophyte species, occurring on calcareous cliffs in the eastern part of Sicily (Italy). The aim of this work is to analyze the structure and floristic composition of theC. tauromenitanacommunity, in order to characterize the diversity of populations in relation to different ecological data. In all, 61 plots were examined. For each plot, the floristic composition and the cover of the species were determined using the standard relevé method. Three vegetation types emerged from canonical components analysis (CCA), correlated to a gradient of environmental conditions ranging from the coast to inland areas. The first group withLomelosia creticaandDianthus rupicolasubsp.rupicolawas correlated to thermo-xerophilous conditions (lower thermo-Mediterranean belt), the second group withSilene fruticosaandColymbada tauromenitanawas linked to thermophilous conditions (upper thermo-Mediterranean belt) and the third withDianthus siculusandOdontites boc-coneiwas correlated to mesophilous conditions (meso-Mediterranean belt). Altitude is the main factor influencing both species richness and floristic composition. The density ofC. tauromenitanais influenced mainly by rainfall. Finally, we propose a new risk status for this rare species.

scholarly journals Floristic composition, structure and soil-vegetation relations in three white-sand soil patches in central Amazonia

2018 ◽  
Vol 48 (1) ◽  
pp. 46-56 ◽  
Author(s):  
Layon Oreste DEMARCHI ◽  
Veridiana Vizoni SCUDELLER ◽  
Livia Carvalho MOURA ◽  
Randolpho Gonçalves DIAS-TERCEIRO ◽  
Aline LOPES ◽  
...  
Keyword(s):  
Species Richness ◽  
Species Composition ◽  
Forest Structure ◽  
Vegetation Type ◽  
Structural Parameters ◽  
Floristic Composition ◽  
Soil Parameters ◽  
Similar Species ◽  
White Sand ◽  
Composition Structure

ABSTRACT The Amazonian white-sand vegetation presents a set of unique features, such as the dominance of a few species, high endemism and low species richness, which differentiate it from other Amazonian forests. Soil parameters have long been recognized as the main drivers of white-sand vegetation (WSV) characteristics. However, how they influence the composition, richness and structure of this vegetation type is still poorly understood. In this study we investigated the variation in floristic composition between patches and the soil-vegetation relations in three central Amazonian WSV patches. We tested whether slight differences in soil properties are linked with differences in floristic composition, species richness and forest structure in adjacent patches. In each patch three plots of 50 x 50 m were sampled (a total of 2.25 ha). Soil samples were collected for each plot. The sampling cutoff for arboreal individuals was DBH ≥ 5 cm. We sampled a total of 3956 individuals belonging to 40 families and 140 species. In each patch only a few species were dominant, but the dominant species varied among patches. Differences among patches were significant, but plots in the same patch tended to have similar species composition. The variable sum of bases (SB) was directly related to species composition, however, species richness and forest structure were not related to soil parameters. Even small variations in soil parameters can change species composition in WSV, although these variations do not necessarily influence the richness and other structural parameters.

scholarly journals Effect of forest fire on floristic composition, structure, dominance and species richness in subtropical pine forest of Ponda watershed, Rajouri, J&K

2014 ◽  
Vol 15 (1&2) ◽  
pp. 61-68
Author(s):  
Junaid Ahmed ◽  
Sanjay Sharma
Keyword(s):  
Species Richness ◽  
Forest Fire ◽  
Basal Area ◽  
Floristic Composition ◽  
Pine Forest ◽  
Total Density ◽  
Forest Stands ◽  
Forest Sites ◽  
Composition Structure ◽  
Trees And Shrubs

Forest fires have profound impacts on physical environment including land cover, land use, forest ecosystem and biodiversity. In the present study the effect of fires on floristic composition, structure, dominance and species richness in subtropical pine forest of Ponda watershed, Rajouri, J&K, lying at an altitude range of 800 m to 1000 m above mean sea level, was assessed. The forests in the study area were divided into two strata i.e., burnt and un-burnt forest. Random sampling was carried out by laying out forty sample plots in all, with twenty sample plots in each strata covering burnt and unburnt forest sites of the study area. The plot dimensions of 20m x 20m were used for studying trees and 5m x 5m for shrubs (laid within the plots for trees). The density, basal area and IVI along with diversity and concentration of dominance of trees and shrubs in both forest sites were studied. Similarity index was also calculated for burnt and unburnt forest of the study area. The results show that the total density and total basal area of trees and shrubs was highest in un-burnt forest sites with density values of 468.75 and 5284 individuals/ha and 85.33 m2/ha and 25.42 m2/ha, respectively. The results on the basis of the comparison of IVI values of all species in both forest stands also reveal that the respective dominant tree and shrub species were Pinus roxburghii and Carissa opaca. The calculated values of Shannon-Wiener, Margalef and Menhinick indices i.e. 1.93, 2.53 and 0.82 for trees and 1.80, 2.08 and 0.44 for shrubs, respectively, reveal that the species richness and diversity was high for unburnt forest stand whereas, Simpson’s index value of tree (0.48) and shrub (0.75) show that an concentration of dominance was highest in burnt forest stands. The calculated value of Sorenson’s and Jaccard’s index of similarity for trees (0.60 and 0.43) was maximum as compare to shrubs (0.47 and 0.31) which shows that forest fire have profound effect on shrub than trees.

Habitat fragmentation causes collapse of kelp recruitment

2020 ◽  
Vol 648 ◽  
pp. 111-123
Author(s):  
C Layton ◽  
MJ Cameron ◽  
M Tatsumi ◽  
V Shelamoff ◽  
JT Wright ◽  
...  
Keyword(s):  
Habitat Fragmentation ◽  
Patch Size ◽  
Life Stage ◽  
Extended Period ◽  
Anthropogenic Disturbances ◽  
Anthropogenic Sources ◽  
Kelp Forests ◽  
Natural Disturbances ◽  
Short Term ◽  
Turf Algae

Kelp forests in many regions are experiencing disturbance from anthropogenic sources such as ocean warming, pollution, and overgrazing. Unlike natural disturbances such as storms, anthropogenic disturbances often manifest as press perturbations that cause persistent alterations to the environment. One consequence is that some kelp forests are becoming increasingly sparse and fragmented. We manipulated patch size of the kelp Ecklonia radiata over 24 mo to simulate persistent habitat fragmentation and assessed how this influenced the demography of macro- and microscopic juvenile kelp within the patches. At the beginning of the experiment, patch formation resulted in short-term increases in E. radiata recruitment in patches <1 m2. However, recruitment collapsed in those same patches over the extended period, with no recruits observed after 15 mo. Experimental transplants of microscopic and macroscopic juvenile sporophytes into the patches failed to identify the life stage impacted by the reductions in patch size, indicating that the effects may be subtle and require extended periods to manifest, and/or that another life stage is responsible. Abiotic measurements within the patches indicated that kelp were less able to engineer the sub-canopy environment in smaller patches. In particular, reduced shading of the sub-canopy in smaller patches was associated with proliferation of sediments and turf algae, which potentially contributed to the collapse of recruitment. We demonstrate the consequences of short- and longer-term degradation of E. radiata habitats and conclude that habitat fragmentation can lead to severe disruptions to kelp demography.

Diversity metrics, species turnovers and nestedness of bird assemblages in a deep karst sinkhole

2017 ◽  
Vol 63 (2) ◽  
pp. 8-16 ◽  
Author(s):  
Corrado Battisti ◽  
Marco Giardini ◽  
Francesca Marini ◽  
Lorena Di Rocco ◽  
Giuseppe Dodaro ◽  
...  
Keyword(s):  
Species Richness ◽  
Random Distribution ◽  
Diversity Index ◽  
Species Turnover ◽  
Floristic Composition ◽  
Bird Assemblages ◽  
Β Diversity ◽  
Stick Model ◽  
Karst Sinkhole

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.

Regularity of species richness relationships to patch size and shape

Ecography ◽  
2007 ◽  
Vol 30 (4) ◽  
pp. 589-597 ◽  
Author(s):  
Einar Heegaard ◽  
Rune H. Økland ◽  
Harald Bratli ◽  
Wenche E. Dramstad ◽  
Gunnar Engan ◽  
...  
Keyword(s):  
Species Richness ◽  
Patch Size ◽  
Size And Shape

scholarly journals Effect of fire on a monodominant floating mat of Cyperus giganteus Vahl in a neotropical wetland

2015 ◽  
Vol 75 (1) ◽  
pp. 114-124 ◽  
Author(s):  
M. Rocha ◽  
CC. Santos Júnior ◽  
GA. Damasceno-Júnior ◽  
VJ. Pott ◽  
A. Pott
Keyword(s):  
Species Richness ◽  
Community Structure ◽  
Annual Variation ◽  
Floristic Composition ◽  
Large Area ◽  
Characteristic Species ◽  
Cyperus Giganteus ◽  
Pantanal Wetland ◽  
Floating Mat ◽  
Adult Plants

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.

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