scholarly journals Exotic species richness and native species endemism increase the impact of exotic species on islands

2011 ◽  
Vol 21 (8) ◽  
pp. 841-850 ◽  
Author(s):  
Jessica C. Walsh ◽  
Oscar Venter ◽  
James E. M. Watson ◽  
Richard A. Fuller ◽  
Tim M. Blackburn ◽  
...  
Keyword(s):  
Species Richness ◽  
Exotic Species ◽  
Native Species ◽  
The Impact

scholarly journals Effect of Urbanization on Vegetation in Riparian Area: Plant Communities in Artificial and Semi-Natural Habitats

2019 ◽  
Vol 12 (1) ◽  
pp. 204 ◽  
Author(s):  
Yang Cao ◽  
Yosihiro Natuhara
Keyword(s):  
Species Richness ◽  
Plant Communities ◽  
Native Species ◽  
Impervious Surface ◽  
Riparian Areas ◽  
Natural Habitats ◽  
Artificial Habitats ◽  
Management Actions ◽  
Impact Of Urbanization ◽  
The Impact

Riparian areas are local hot spots of biodiversity that are vulnerable and easily degraded. Comparing plant communities in habitats with different degrees of urbanization may provide valuable information for the management and restoration of these vulnerable habitats. In this study, we explored the impact of urbanization on vegetation communities between artificial and semi-natural habitats within two rivers with different levels of development. We compared species richness, types of vegetation, and composition patterns of the plants in our study. In artificial habitats, the sites with relatively high levels of urbanization had the highest species richness, while in semi-natural habitats, the highest species richness was recorded in the less urbanized sites. Furthermore, every component of urbanization that contributed to the variation of species richness was examined in the current study. In artificial habitats, the proportion of impervious surface was the strongest predictor of the variation in species richness and was associated with the richness of alien, native, and riparian species. In semi-natural habitats, most of the richness of alien and native species were associated with the distance to the city center, and the number of riparian and ruderal species was significantly related to the proportion of impervious surface. Moreover, we found that a high level of urbanization was always associated with a large abundance of alien and ruderal species in both artificial and in semi-natural habitats. We recommend the methods of pair comparison of multiple rivers to analyze the impact of urbanization on plant species in riparian areas and have suggested various management actions for maintaining biodiversity and sustainability in riparian ecosystems.

Vegetation change in an urban grassy woodland 1974 - 2000

2004 ◽  
Vol 52 (5) ◽  
pp. 597 ◽  
Author(s):  
J. B. Kirkpatrick
Keyword(s):  
Species Richness ◽  
Species Composition ◽  
Exotic Species ◽  
Native Species ◽  
Vegetation Change ◽  
Structural Changes ◽  
Linear Models ◽  
Tree Cover ◽  
Native Plant ◽  
Native Species Richness

Few temporal studies document vegetation change in Australian temperate grassy woodlands. Floristic and structural data were collected from 68 randomly located sites in the Queens Domain, an urban grassy woodland remnant, in 1974, 1984, 1994 and 2000 and a search made for rare species. Species of conservation significance were concentrated at highly disturbed sites, whereas vegetation types of conservation significance decreased in area as a result of increases in the numbers of Allocasuarina verticillata, which caused a change in many unmown areas from Eucalyptus viminalis grassy woodland to E. viminalis–A. verticillata woodland/forest or A. verticillata open/closed forest. Structural changes were associated with changes in species composition and an increase in native-species richness. Increases in tree cover occurred where fires were most frequent, possibly as a result of the lack of mammalian herbivores. The frequencies of herbs and annual grasses were strongly affected by precipitation in the month of sampling. Half of the species that showed a consistent rise or fall through time were woody plants, approximately twice the number expected. In the dataset as a whole, species-richness variables were largely explained by varying combinations of variables related to moisture availability, altitude and the incidence of mowing. The strongest influences on species composition were the same, although slope and time since the last fire also contributed to multiple regression and generalised linear models. Compositional stability was positively related to native-species richness, whereas high levels of exotic-species richness occurred at both low and high levels of native-species richness. The maintenance of native-plant biodiversity on the Domain requires such counterintuitive measures as the maintenance of exotic trees and the control of native trees, demonstrating the contingencies of conservation management in fragmented vegetation that consists of a mixture of native and exotic species.

scholarly journals Species richness, phylogenetic diversity and phylogenetic structure patterns of exotic and native plants along an elevational gradient in the Himalaya

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Kumar Manish
Keyword(s):  
Species Richness ◽  
Exotic Species ◽  
Native Species ◽  
Phylogenetic Diversity ◽  
Elevational Gradient ◽  
Species Assemblages ◽  
Native Plant ◽  
Phylogenetic Structure ◽  
Phylogenetic Overdispersion ◽  
The Himalaya

Abstract Background So far, macroecological studies in the Himalaya have mostly concentrated on spatial variation of overall species richness along the elevational gradient. Very few studies have attempted to document the difference in elevational richness patterns of native and exotic species. In this study, this knowledge gap is addressed by integrating data on phylogeny and elevational distribution of species to identify the variation in species richness, phylogenetic diversity and phylogenetic structure of exotic and native plant species along an elevational gradient in the Himalaya. Results Species distribution patterns for exotic and native species differed; exotics tended to show maximum species richness at low elevations while natives tended to predominate at mid-elevations. Native species assemblages showed higher phylogenetic diversity than the exotic species assemblages over the entire elevational gradient in the Himalaya. In terms of phylogenetic structure, exotic species assemblages showed majorly phylogenetic clustering while native species assemblages were characterized by phylogenetic overdispersion over the entire gradient. Conclusions The findings of this study indicate that areas with high native species richness and phylogenetic diversity are less receptive to exotic species and vice versa in the Himalaya. Species assemblages with high native phylogenetic overdispersion are less receptive to exotic species than the phylogenetically clustered assemblages. Different ecological processes (ecological filtering in case of exotics and resource and niche competition in case of natives) may govern the distribution of exotic and native species along the elevational gradient in the Himalaya.

scholarly journals Espécies nativas que podem substituir as exóticas no paisagismo

2015 ◽  
Vol 21 (2) ◽  
pp. 165 ◽  
Author(s):  
Elisabeth Regina Tempel Stumpf ◽  
Patrick Da Silva Silva ◽  
Isadora Dias Romagnoli ◽  
Síntia Zitzke Fischer ◽  
Márcio Paim Mariot
Keyword(s):  
Exotic Species ◽  
Native Species ◽  
Urban Spaces ◽  
Native Flora ◽  
Commercial Cultivation ◽  
Chemical Products ◽  
The Impact ◽  
Flora Diversity ◽  
Landscape Gardening

Beyond aesthetics, the contemporary landscaping intends to provide other benefits for humans and environment, especially related to the environmental quality of urban spaces and conservation of the species. A trend in this direction is the reduction in the use of exotic plants in their designs, since, over time, they can become agents of replacement of native flora, as it has occurred in Rio Grande do Sul with many species introduced by settlers. However, the use of exotic species is unjustifiable, because the flora diversity of the Bioma Pampa offers many native species with appropriate features to the ornamental use. The commercial cultivation and the implantation of native species in landscaped areas constitute innovations for plant nurseries and landscapers and can provide a positive reduction in extractivism, contributing to dissemination, exploitation and preservation of native flora, and also decrease the impact of chemical products on environment. So, this work intends to identify native species of Bioma Pampa with features and uses similar to the most used exotic species at Brazilian landscaping. The species were selected from consulting books about native plants of Bioma Pampa and plants used at Brazilian landscaping, considering the similarity on habit and architecture, as well as characteristics of leafs, flowers and/or fruits and environmental conditions of occurrence and cultivation. There were identified 34 native species able to properly replace exotic species commonly used. The results show that many native species of Bioma Pampa have interesting ornamental features to landscape gardening, allowing them to replace exotic species that are traditionally cultivated.

scholarly journals Patterns of Understory Diversity in Mixed Coniferous Forests of Southern California Impacted by Air Pollution

2007 ◽  
Vol 7 ◽  
pp. 247-263 ◽  
Author(s):  
Edith B. Allen ◽  
Patrick J. Temple ◽  
Andrzej Bytnerowicz ◽  
Michael J. Arbaugh ◽  
Abby G. Sirulnik ◽  
...  
Keyword(s):  
Air Pollution ◽  
Species Richness ◽  
Exotic Species ◽  
Native Species ◽  
Basal Area ◽  
N Deposition ◽  
Understory Vegetation ◽  
Species Number ◽  
San Bernardino Mountains ◽  
Long Term Study

The forests of the San Bernardino Mountains have been subject to ozone and nitrogen (N) deposition for some 60 years. Much work has been done to assess the impacts of these pollutants on trees, but little is known about how the diverse understory flora has fared. Understory vegetation has declined in diversity in response to elevated N in the eastern U.S. and Europe. Six sites along an ozone and N deposition gradient that had been part of a long-term study on response of plants to air pollution beginning in 1973 were resampled in 2003. Historic ozone data and leaf injury scores confirmed the gradient. Present-day ozone levels were almost half of these, and recent atmospheric N pollution concentrations confirmed the continued air pollution gradient. Both total and extractable soil N were higher in sites on the western end of the gradient closer to the urban source of pollution, pH was lower, and soil carbon (C) and litter were higher. The gradient also had decreasing precipitation and increasing elevation from west to east. However, the dominant tree species were the same across the gradient.Tree basal area increased during the 30-year interval in five of the sites. The two westernmost sites had 30–45% cover divided equally between native and exotic understory herbaceous species, while the other sites had only 3–13% cover dominated by native species. The high production is likely related to higher precipitation at the western sites as well as elevated N. The species richness was in the range of 24 to 30 in four of the sites, but one site of intermediate N deposition had 42 species, while the easternmost, least polluted site had 57 species. These were primarily native species, as no site had more than one to three exotic species. In three of six sites, 20–40% of species were lost between 1973 and 2003, including the two westernmost sites. Two sites with intermediate pollution had little change in total species number over 30 years, and the easternmost site had more species in 2003. The easternmost site is also the driest and has the most sunlight filtering to the forest floor, possibly accounting for the higher species richness. The confounding effects of the precipitation gradient and possibly local disturbances do not show a simple correlation of air pollution with patterns of native and invasive species cover and richness. Nevertheless, the decline of native species and dominance by exotic species in the two westernmost polluted sites is cause for concern that air pollution is affecting the understory vegetation adversely.

Impact of the introduced poeciliid Gambusia holbrooki (Girard, 1859) on the growth and reproduction of Pseudomugil signifer (Kner, 1865) in Australia

1997 ◽  
Vol 48 (5) ◽  
pp. 425 ◽  
Author(s):  
Effie Howe ◽  
Christopher Howe ◽  
Richard Lim ◽  
Margaret Burchett
Keyword(s):  
Exotic Species ◽  
Native Species ◽  
Deleterious Effect ◽  
Gambusia Holbrooki ◽  
Ovarian Weight ◽  
Total Length ◽  
The Impact ◽  
Growth And Reproduction

The impact of the presence of the introduced poeciliid Gambusia holbrooki on the Australian pseudomugilid Pseudomugil signifer was examined in open-air tank experiments. G. holbrooki profoundly affected the breeding of P. signifer. In the presence of G. holbrooki, P. signifer did not gain weight or grow in total length, ovarian weight and fecundity were greatly reduced, and the ovaries were morphologically undeveloped. No eggs of P. signifer were observed in tanks that also housed G. holbrooki. The results indicate that, at least in a captive situation, the presence of the exotic species had a very deleterious effect on the breeding and hence possible survival of the native species. These results are discussed with reference to the conservation of Australian pseudomugilid species, especially those inhabiting confined habitats.

scholarly journals Myrmecological diversity (Hymenoptera: Formicidae) in Tamaulipas, México

2021 ◽  
Vol 80 (04) ◽  
pp. 81-99
Author(s):  
Itzel Rodríguez de León ◽  
Lidia Guzmán-Díaz ◽  
Madai Rosas Mejía
Keyword(s):  
Species Richness ◽  
Exotic Species ◽  
Native Species ◽  
The State ◽  
Biological Collections

This investigation involved analyzing 77 publications, 6 national biological collections and an international collection and determining the myrmecological diversity of Tamaulipas, which consists of 195 species that belong to 60 genera, with 410 records in the state. The genera with the highest species richness were Camponotus Mayr (Formicinae), Pheidole Westwood (Myrmicinae) and Neivamyrmex Borgmeier (Dorylinae), with 17, 15 and 12 species, respectively. The ant fauna of Tamaulipas consists of 95% native species and 5% exotic species. The investigation determined that 25 municipalities had been sampled, and Gómez Farías, Victoria and Jaumave stood out with the highest number of ant species records; however, 18 municipalities that provide opportunities to increase the knowledge of Formicidae remain unexplored.

Effects of fire frequency and microhabitat on the ground layer in a grassy woodland

2020 ◽  
Vol 68 (6) ◽  
pp. 425
Author(s):  
Penny J. Watson ◽  
E. Charles Morris
Keyword(s):  
Species Richness ◽  
Exotic Species ◽  
Relative Abundance ◽  
Native Species ◽  
Fire Frequency ◽  
Ground Layer ◽  
Similar Time ◽  
Themeda Triandra ◽  
Total Species ◽  
Native Species Richness

Grassy woodlands worldwide are vertically structured by trees, a ground layer of grasses and forbs, and a variable mid-storey. In Western Sydney’s Cumberland Plain Woodland this mid-storey is increasingly dominated by the prickly shrub Bursaria spinosa Cav. subsp. spinosa. We investigated whether tree and shrub vegetation affects species richness and composition of ground layer microhabitats in this woodland, and whether fire frequency directly affects the ground layer in addition to any indirect effects via overstorey vegetation. Replicate sites were located in areas that had burnt with a frequency that was high, moderate or low. All sites had a similar time since last fire. Three microhabitats (open, under Bursaria, around tree) within each site were sampled for species richness and composition of native and exotic species. Native species richness was not significantly affected by either microhabitat or fire frequency, for total species, grasses or forbs; however the relative abundance of native grasses decreased significantly as fire frequency declined, while the relative abundance of native forbs increased. Exotic species richness was lowest at high fire frequency and significantly higher at low fire frequency. Species composition was significantly affected by both microhabitat and fire frequency combining independently. Planned burning at relatively short intervals can help managers retain grassy habitat for open patch species, habitat for ground layer species that do best under frequent fire, and a robust Themeda triandra Forssk. sward antagonistic to weeds.

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