Vegetation change 10 years after cattle removal in a savanna landscape

2020 ◽  
Vol 42 (2) ◽  
pp. 73 ◽  
Author(s):  
Jeanette E. Kemp ◽  
Alexander S. Kutt
Keyword(s):  
Species Richness ◽  
Vegetation Change ◽  
Floristic Composition ◽  
Grazing Pressure ◽  
Plant Functional Groups ◽  
Negative Results ◽  
Introduced Plants ◽  
Relative Cover ◽  
Stylosanthes Scabra ◽  
Pasture Legume

Following the establishment of a conservation reserve, changes in ground stratum vegetation following removal of cattle were examined in a northern Australian savanna over a 10-year period. The floristic composition of 40 vegetation plots in lowland savannas were surveyed shortly after acquisition of the property, and then surveyed twice in the following 10 years after cattle removal. Some notable ecosystem-transforming introduced species (weeds) such as Themeda quadrivalvis remained relatively stable, whereas the pasture legume Stylosanthes scabra increased in cover. The species richness of both native and introduced plants increased. Various plant functional groups changed in relative cover, with a decline in relatively unpalatable grasses and a corresponding increase in palatable grasses, responses that are consistent with recovery from grazing pressure. Our results show that removal of cattle in highly disturbed savanna ecosystems can have both positive and negative results for native ground stratum vegetation in the first decade of recovery.

Changes in Floristic Composition of Urban Bushland Invaded by Pittosporum undulatum in Northern Sydney, Australia

1997 ◽  
Vol 45 (1) ◽  
pp. 123 ◽  
Author(s):  
Stefan Rose ◽  
Peter G. Fairweather
Keyword(s):  
Species Richness ◽  
Exotic Species ◽  
Native Species ◽  
Floristic Composition ◽  
Individual Species ◽  
Community Pattern ◽  
Edaphic Conditions ◽  
Management Effort ◽  
Relative Cover ◽  
Native Species Richness

Differences in species composition of urban bushland sites that had been subjected to increasing degradation and progressive invasion of Pittosporum undulatum Vent. were assessed using nonparametric multivariate and other statistical techniques. Increasing suburb age was found to significantly affect community pattern as a whole, specifically through increased proportions of exotic species, decreased native species richness and sustained shifts in the relative importance of individual species. Older suburbs were typified by species that were mesic, fire-sensitive, shade-tolerant and adapted to relatively moist, nutrient-rich edaphic conditions. These species included P. undulatum and many invasive exotics. Many native species decreased substantially in rank importance with increasing suburb age, to the point of elimination in older suburbs. These included one vulnerable taxon (Tetratheca glandulosa Sm.). Overall community pattern was correlated with abundance of P. undulatum, fire and human disturbance. Relative cover of P. undulatum was found to be significantly correlated with increased proportions of exotic species and reduced native species richness and diversity. While most exotic species were concentrated within 30 m of the suburban edge, it is suggested that most management effort should be directed at those exotic species that commonly establish throughout bushland remnants. The study also provided an opportunity to test the application of the multivariate software package PRIMER in assessing environmental impact on vegetation communities.

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.

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.

scholarly journals Floristic composition of the Montane Forest in the Almadina-Barro Preto axis, Southern Bahia, Brazil

2014 ◽  
Vol 14 (1) ◽  
Author(s):  
Macielle Macedo Coelho ◽  
André Márcio Amorim
Keyword(s):  
Species Richness ◽  
Tropical Forests ◽  
Atlantic Forest ◽  
Floristic Composition ◽  
Woody Species ◽  
Life Forms ◽  
Montane Forest ◽  
Forest Remnants ◽  
Southern Bahia ◽  
Arboreal Habit

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.

scholarly journals Effects of reindeer grazing and recovery after cessation of grazing on the ground-dwelling spider assemblage in Finnish Lapland

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7330
Author(s):  
Teemu Saikkonen ◽  
Varpu Vahtera ◽  
Seppo Koponen ◽  
Otso Suominen
Keyword(s):  
Species Richness ◽  
Rangifer Tarandus ◽  
Forest Ecosystems ◽  
Grazing Pressure ◽  
Ground Vegetation ◽  
Total Abundance ◽  
Finnish Lapland ◽  
Species Specific ◽  
The Impact

The effect of reindeer Rangifer tarandus L. grazing on the ground-dwelling spider assemblage in Northern Finland was studied. Changes in species richness, abundance and evenness of spider assemblages were analyzed in relation to changes in vegetation and environmental factors in long term grazed and ungrazed sites as well as sites that had recently switched from grazed to ungrazed and vice versa. Grazing was found to have a significant impact on height and biomass of lichens and other ground vegetation. However, it seemed not to have an impact on the total abundance of spiders. This is likely caused by opposing family and species level responses of spiders to the grazing regime. Lycosid numbers were highest in grazed and linyphiid numbers in ungrazed areas. Lycosidae species richness was highest in ungrazed areas whereas Linyphiidae richness showed no response to grazing. Four Linyphiidae, one Thomisidae and one Lycosidae species showed strong preference for specific treatments. Sites that had recovered from grazing for nine years and the sites that were grazed for the last nine years but were previously ungrazed resembled the long term grazed sites. The results emphasize the importance of reindeer as a modifier of boreal forest ecosystems but the impact of reindeer grazing on spiders seems to be family and species specific. The sites with reversed grazing treatment demonstrate that recovery from strong grazing pressure at these high latitudes is a slow process whereas reindeer can rapidly change the conditions in previously ungrazed sites similar to long term heavily grazed conditions.

Using Lindenmayer systems to model morphogenesis in a tropical pasture legume Stylosanthes scabra

1999 ◽  
Vol 77 (3) ◽  
pp. 394-403 ◽  
Author(s):  
Peter A Wilson ◽  
James S Hanan ◽  
Peter M Room ◽  
Sukumar Chakraborty ◽  
David Doley
Keyword(s):  
Morphological Data ◽  
Growth Data ◽  
Lindenmayer Systems ◽  
Virtual Plant ◽  
Total Leaf ◽  
Systems Modelling ◽  
Plant Form ◽  
Pasture Plant ◽  
Stylosanthes Scabra ◽  
Pasture Legume

This paper summarizes the processes involved in designing a mathematical model of a growing pasture plant, Stylosanthes scabra Vog. cv. Fitzroy. The model is based on the mathematical formalism of Lindenmayer systems and yields realistic computer-generated images of progressive plant geometry through time. The processes involved in attaining growth data, retrieving useful growth rules, and constructing a "virtual plant" model are outlined. Progressive output morphological data proved useful for predicting total leaf area and allowed for easier quantification of plant canopy size in terms of biomass and total leaf area.Key words: Lindenmayer systems, modelling, Stylosanthes, morphogenesis, plant form.

Vegetation damage caused by high densities of burrowing bettongs (Bettongia lesueur) at Arid Recovery

2017 ◽  
Vol 39 (1) ◽  
pp. 33 ◽  
Author(s):  
Grant D. Linley ◽  
Katherine E. Moseby ◽  
David C. Paton
Keyword(s):  
Species Richness ◽  
Plant Species ◽  
Plant Species Richness ◽  
Grazing Pressure ◽  
Dodonaea Viscosa ◽  
Perennial Plant ◽  
Vegetation Condition ◽  
Acacia Aneura ◽  
Acacia Ligulata ◽  
Vegetation Damage

Burrowing bettongs (Bettongia lesueur) reached high densities within the fenced Arid Recovery reserve. Grazing pressure was assessed by comparing the vegetation inside and outside the reserve during April in 2012, 2013 and 2014. Mean numbers of bettong tracks crossing small 10 m × 1 m plots overnight in the main exclosure were 20 in 2012, decreasing to 4 in 2013 and 3 in 2014. Similar declines were present in the second expansion, where tracks decreased from 7 in 2012 to 3 in 2013 and 2 in 2014. Perennial plant species richness decreased significantly over the study period. Acacia aneura, Acacia ligulata, Atriplex vesicaria, Crotalaria eremaea, Dodonaea viscosa, Enchylaena tomentosa, Maireana astrotricha and Sida ammophila were the most heavily grazed species within the reserve. Overall, more than 25% of plants showed some form of conspicuous grazing. C. eremaea and E. tomentosa showed little damage outside the reserve. Inside the reserve many C. eremaea were dead and heavily browsed and few E. tomentosa remained. Recent recruitment of A. ligulata and D. viscosa was also much higher outside the reserve. High densities of burrowing bettongs were associated with declines in vegetation condition potentially impacting other species and the ecosystem as a whole.

scholarly journals Effects of environmental conditions and space on species turnover for three plant functional groups in Brazilian savannas

2019 ◽  
Vol 12 (6) ◽  
pp. 1047-1058 ◽  
Author(s):  
Hélio Menegat ◽  
Divino Vicente Silvério ◽  
Henrique A Mews ◽  
Guarino R Colli ◽  
Ana Clara Abadia ◽  
...  
Keyword(s):  
Functional Groups ◽  
Environmental Conditions ◽  
Environmental Gradients ◽  
Species Turnover ◽  
Geographic Distance ◽  
Floristic Composition ◽  
Environmental Variation ◽  
Variance Partitioning ◽  
Plant Functional Groups ◽  
Palm Species

Abstract Aims Different plant functional groups display diverging responses to the same environmental gradients. Here, we assess the effects of environmental and spatial predictors on species turnover of three functional groups of Brazilian savannas (Cerrado) plants—trees, palms and lianas—across the transition zone between the Cerrado and Amazon biomes in central Brazil. Methods We used edaphic, climatic and plant composition data from nine one-hectare plots to assess the effects of the environment and space on species turnover using a Redundancy Analysis and Generalized Dissimilarity Modeling (GDM), associated with variance partitioning. Important Findings We recorded 167 tree species, 5 palms and 4 liana species. Environmental variation was most important in explaining species turnover, relative to geographic distance, but the best predictors differed between functional groups: geographic distance and silt for lianas; silt for palms; geographic distance, temperature and elevation for trees. Geographic distances alone exerted little influence over species turnover for the three functional groups. The pure environmental variation explained most of the liana and palm turnover, while tree turnover was largely explained by the shared spatial and environmental contribution. The effects of geographic distance upon species turnover leveled off at about 300 km for trees, and 200 km for lianas, whereas they were unimportant for palm species turnover. Our results indicate that environmental factors that determine floristic composition and species turnover differ substantially between plant functional groups in savannas. Therefore, we recommend that studies that aim to investigate the role of environmental conditions in determining plant species turnover should examine plant functional groups separately.

The Douglas-fir forests of Banff and Jasper National Parks, Canada

1970 ◽  
Vol 48 (10) ◽  
pp. 1703-1726 ◽  
Author(s):  
Paul W. Stringer ◽  
George H. La Roi
Keyword(s):  
National Parks ◽  
Populus Tremuloides ◽  
Picea Glauca ◽  
Pinus Contorta ◽  
Vegetation Change ◽  
Floristic Composition ◽  
Stand Age ◽  
Physical Habitat ◽  
Regression Equations ◽  
Habitat Differences

Twenty stands of uniform, mature, undisturbed Pseudotsuga menziesii var. glauca forest were selected in Banff and Jasper National Parks, using a combination of airphoto and ground surveys. Quantitative sampling methods were used to describe their floristic composition, vegetation structure, and physical habitats.Scattered trees of Pinus contorta, Picea glauca, and Populus tremuloides occurred in the Pseudotsuga forests. The poorly developed shrub strata contained Shepherdia canadensis, Rosa acicularis, Spiraea lucida, Juniperus communis. Major herb, dwarf shrub, bryophyte, and lichen species were Elymus innovatus, Calamagrostis rubescens, Fragaria virginiana, Astragalus decumbens, Aster conspicuus; Arctostaphylos uva-ursi, Linnaea borealis; Hylocomium splendens, Abietinella abietina, Tortula ruralis; Peltigera canina. A cyclical pattern of vegetation change is related to the death, replacement, and maturation of Pseudotsuga trees.Relations between vegetation and physical habitat were analyzed by simple correlation and multiple regression. Available potassium in soil, stand age, and slope exposure were most influential in regression equations for tree stratum development. Understory strata were primarily correlated with tree stratum development.A two-dimensional stand ordination based on the vegetational similarity of subordinate vascular strata showed a pronounced separation of Banff and Jasper Pseudotsuga forests, and prompted recognition of two new climax associations (sensu Daubenmire): Pseudotsuga / Elymus innovatus in Jasper; Pseudotsuga / Calamagrostis rubescens – Elymus innovatus in Banff. Habitat differences between the two associations include macroclimate, parent materials, and soil moisture.

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