scholarly journals Effects of Native Species Diversity and Resource Additions on Invader Impact

2008 ◽  
Vol 172 (S1) ◽  
pp. S18-S33 ◽  
Author(s):  
John L. Maron ◽  
Marilyn Marler
2021 ◽  
Vol 24 (4) ◽  
pp. 389-401
Author(s):  
Soo-Dong Lee ◽  
Seung-Jun Back ◽  
Hyun-Kyung Kang

Background and objective: The purpose of this study is to investigate the ecological status of six areas around Geumgang River that used to be farmlands before they were restored as a riverine ecobelt. This study aims to analyze the correlation between the location environment and ecological status of the sites to identify the environmental factors affecting them. Methods: The sites are classified into four types according to restoration: terraced paddy fields, flat paddy fields, artificial wetland, and landscape forest. The survey items were divided into land use status, plant ecology, and animal ecology. Results: In terms of plant ecology, terraced paddy fields showed favorable naturality with the rate of native species above 90% and the naturalization index below 10%. In terms of animal ecology, the total number of species found in these areas was biggest in terraced paddy fields, followed by flat paddy fields, artificial wetland, and landscape forest. Regarding species diversity, terraced paddy fields also showed abundant species with an average of 1.05 to 1.09. The results of the correlation analysis showed that the forest area around the sites had the most significant effect on species diversity. The grassland and open water area showed a positive correlation with the total number of animal species and the number of dragonflies, confirming that the marshy grassland had a positive effect. As the cultivated land and urbanized area around the sites increased, it had a negative effect on the distribution of native species and the number of animal species that appeared, and a positive effect on the naturalization index. Conclusion: It is necessary to establish preemption and restoration plans for sites such as grasslands adjacent to the forest and terraced paddy fields in order to promote resilience of the diverse species returning to the purchased lands.


2018 ◽  
Vol 63 (12) ◽  
pp. 1514-1522 ◽  
Author(s):  
Justin S. Kemp ◽  
Feng Tang ◽  
David C. Aldridge

1981 ◽  
Vol 8 (1) ◽  
pp. 109 ◽  
Author(s):  
DN Jones

The suburban bird community of Wagga Wagga, N.S.W., was surveyed during December 1978-January 1979 and May 1979, at nine sites selected to cover all ages of residential areas from predevelopment to oldest suburbs and to demonstrate how the bird community will change with time in response to changing habitat. Non-residential sites were also sampled. Sites were censused by foot transect. House sparrows which were present in all sites, were the first species to colonize new residential areas and made up over 95% of the individual count of four sites Of native species, 40% were found in undeveloped sites only. The population density of undeveloped sites was only half that of developed sites, but the greatest species diversity was found in undeveloped sites and the lowest in the most altered sites. There was strong evidence for a steady linear increase in numbers of individuals, numbers of species, biomass and population density with increasing age of residential area, reaching a peak at about 30 years.


2020 ◽  
Vol 55 (4) ◽  
pp. 469-486
Author(s):  
Reid M. Ipser ◽  
Wayne A. Gardner

Abstract The red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), and ground-dwelling ant species native to Georgia were observed and studied in tree-canopied and open uncanopied habitats in two state parks in central Georgia. Population density, native species diversity, and interactions of native species with each other and with the invasive S. invicta were determined and compared in the two habitats. Sampling methods included pitfall traps, baits, collection of leaf litter, and visual searches. In comparison to the open uncanopied habitats, red imported fire ant population density was lower in tree-canopied habitats, and native ant species diversity was greater in the canopied habitats. We also observed native species competing with red imported fire ants more intensely in canopied than in open habitats primarily by foraging activity and by predation of S. invicta reproductives. Our results suggest that native ant species can suppress S. invicta population numbers and density and that competition by native ant species should be considered in approaches of managing red imported fire ant.


2010 ◽  
Vol 16 (3) ◽  
pp. 162 ◽  
Author(s):  
Maggie Lilith ◽  
Michael Calver ◽  
Mark Garkaklis

We took advantage of cat regulations enacted within differing subdivisions in the City of Armadale, Western Australia, to test the hypotheses that the species diversity (measured by the Shannon-Weiner index) and abundance of small and medium-sized mammals should be higher in native bushland within or adjacent to subdivisions where cats are restricted compared to similar areas where cats are not restricted. There were three different regimes of cat regulation: no-cat zone (strict prohibition of cat ownership applying in one site), compulsory belling of cats and night curfew at one site, and unregulated zones (free-roaming cats applying at two sites). Both sets of cat regulations were in place for approximately 10 years prior to our survey. We also measured structural and floristic features of the vegetation at each site that might influence the species diversity and abundance of small and medium-sized mammals independently or interactively with cat activity. No significant differences in species diversity were found across the sites and KTBA (known-to-be-alive) statistics for Brushtail Possums Trichosurus vulpecula and Southern Brown Bandicoots Isoodon obesulus, the two most abundant medium-sized mammals present, were similar across all sites. The smaller Mardo Antechinus flavipes, which could be regarded as the most susceptible to cat predation of all the native species trapped because of its size, was trapped mostly at an unregulated cat site. Total mammals trapped at the unregulated cat sites exceeded those caught at the two sites with restrictions, but these unregulated sites also had significantly denser vegetation and there was a borderline (p = 0.05) rank correlation between vegetation density and mammal captures across all sites. It appears that pet cats are not the major influence on the species diversity or abundance of small and medium-sized mammals at these sites and that vegetation characteristics may be more important.


Author(s):  
T.H. Oliver

Human activities in the Anthropocene are influencing the twin processes of biodiversity generation and loss in complex ways that threaten the maintenance of biodiversity levels that underpin human well-being. Yet many scientists and practitioners still present a simplistic view of biodiversity as a static stock rather than one determined by a dynamic interplay of feedback processes that are affected by anthropogenic drivers. Biodiversity describes the variety of life on Earth, from the genes within an organism to the ecosystem level. However, this article focuses on variation among living organisms, both within and between species. Within species, biodiversity is reflected in genetic, and consequent phenotypic, variations among individuals. Genetic diversity is generated by germ line mutations, genetic recombination during sexual reproduction, and immigration of new genotypes into populations. Across species, biodiversity is reflected in the number of different species present and also, by some metrics, in the evenness of their relative abundance. At this level, biodiversity is generated by processes of speciation and immigration of new species into an area. Anthropogenic drivers affect all these biodiversity generation processes, while the levels of genetic diversity can feed back and affect the level of species diversity, and vice versa. Therefore, biodiversity maintenance is a complex balance of processes and the biodiversity levels at any point in time may not be at equilibrium. A major concern for humans is that our activities are driving rapid losses of biodiversity, which outweigh by orders of magnitude the processes of biodiversity generation. A wide range of species and genetic diversity could be necessary for the provision of ecosystem functions and services (e.g., in maintaining the nutrient cycling, plant productivity, pollination, and pest control that underpin crop production). The importance of biodiversity becomes particularly marked over longer time periods, and especially under varying environmental conditions. In terms of biodiversity losses, there are natural processes that cause roughly continuous, low-level losses, but there is also strong evidence from fossil records for transient events in which exceptionally large loss of biodiversity has occurred. These major extinction episodes are thought to have been caused by various large-scale environmental perturbations, such as volcanic eruptions, sea-level falls, climatic changes, and asteroid impacts. From all these events, biodiversity has shown recovery over subsequent calmer periods, although the composition of higher-level evolutionary taxa can be significantly altered. In the modern era, biodiversity appears to be undergoing another mass extinction event, driven by large-scale human impacts. The primary mechanisms of biodiversity loss caused by humans vary over time and by geographic region, but they include overexploitation, habitat loss, climate change, pollution (e.g., nitrogen deposition), and the introduction of non-native species. It is worth noting that human activities may also lead to increases in biodiversity in some areas through species introductions and climatic changes, although these overall increases in species richness may come at the cost of loss of native species, and with uncertain effects on ecosystem service delivery. Genetic diversity is also affected by human activities, with many examples of erosion of diversity through crop and livestock breeding or through the decline in abundance of wild species populations. Significant future challenges are to develop better ways to monitor the drivers of biodiversity loss and biodiversity levels themselves, making use of new technologies, and improving coverage across geographic regions and taxonomic scope. Rather than treating biodiversity as a simple stock at equilibrium, developing a deeper understanding of the complex interactions—both between environmental drivers and between genetic and species diversity—is essential to manage and maintain the benefits that biodiversity delivers to humans, as well as to safeguard the intrinsic value of the Earth’s biodiversity for future generations.


2020 ◽  
Vol 15 (2) ◽  
pp. 225-228
Author(s):  
P V Rami Reddy

Decline in honey bee populations has become a matter of concern and their conservation is very essential to sustain essential ecosystem services. They provide making available continuous supply of floral resources is of immense value in conserving honey bees. The effectiveness of an ornamental creeper, Antigonon leptopus Hook. & Arn as a sustainable bee forage plant was evaluated. It attracts four major native species of honey bees viz., Apis cerana, A. florea, A. dorsata and Tetragonula iridipennis. The wild little bee, A. florea was the most dominant forager followed by the Indian bee, A. cerana. The plant is amenable for easy multiplication through seeds as well as cuttings and meets both aesthetic and ecological needs. Using Antigonon, different studies related to honey bees like assessing species diversity, foraging behaviour, temperature driven shifts etc. can be carried out. Popularising perennial bee flora like Antigonon would help in conserving honey bees in both natural and urban habitats. Since Antigonon attracts all species of honey bees throughout the year, it could be utilized as a potential bioindicator of honey bee populations in a given environment.


2019 ◽  
Vol 116 (15) ◽  
pp. 7382-7386 ◽  
Author(s):  
Qinfeng Guo ◽  
Songlin Fei ◽  
Kevin M. Potter ◽  
Andrew M. Liebhold ◽  
Jun Wen

Nonnative pests often cause cascading ecological impacts, leading to detrimental socioeconomic consequences; however, how plant diversity may influence insect and disease invasions remains unclear. High species diversity in host communities may promote pest invasions by providing more niches (i.e., facilitation), but it can also diminish invasion success because low host dominance may make it more difficult for pests to establish (i.e., dilution). Most studies to date have focused on small-scale, experimental, or individual pest/disease species, while large-scale empirical studies, especially in natural ecosystems, are extremely rare. Using subcontinental-level data, we examined the role of tree diversity on pest invasion across the conterminous United States and found that the tree-pest diversity relationships are hump-shaped. Pest diversity increases with tree diversity at low tree diversity (because of facilitation or amplification) and is reduced at higher tree diversity (as a result of dilution). Thus, tree diversity likely regulates forest pest invasion through both facilitation and dilution that operate simultaneously, but their relative strengths vary with overall diversity. Our findings suggest the role of native species diversity in regulating nonnative pest invasions.


Diversity ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 579
Author(s):  
Lilian A. Palomino-Alvarez ◽  
Xochitl G. Vital ◽  
Raúl E. Castillo-Cupul ◽  
Nancy Y. Suárez-Mozo ◽  
Diana Ugalde ◽  
...  

Autonomous reef monitoring structures (ARMS) have been proposed as a standardized, passive, nondestructive sampling tool. This study assessed the ability of ARMS to capture the cryptic species diversity of two coral reefs by recording species richness and taxonomic representativeness using conventional taxonomy. The capacity of ARMS, as artificial substrates, to favor the establishment of nonindigenous species over native species was also evaluated. The use of ARMS allowed the detection of 370 species morphotypes from nine phyla, yielding 13 new records of geographic distribution expansion, one exotic species for the Gulf of México and the Caribbean Sea, and six newly described species. It was also possible to make spatial comparisons of species richness between both reefs. ARMS captured cryptic diversity exceptionally well, with the exception of echinoderms. Furthermore, these artificial structures did not hinder the colonization ability of native species; in fact, the colonization patterns on the structures themselves represented the spatial differences in the structure of benthic assemblages. This study represents the first effort to make a conventional taxonomic description of the cryptic fauna of the Yucatan Peninsula using ARMS. It is recommended to assess coral reef species diversity, but more taxonomists specialized in marine invertebrates are needed.


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