Displacement Of Native Species Research Articles

Responses of Common Reed ( Phragmites australis ) to Nitrogen and Temperature Manipulations

Invasion of introduced lineage of common reed ( Phragmites australis ) into water-saturated communities in the Great Plains has modified habitats and ecosystem services. In several areas it grows alongside and out-competes its native counterpart. We investigated ecophysiological responses of the two lineages to nitrogen (N) fertilization and temperature (19°, 25°, and 32°C). Photosynthesis (A max ) did not differ between lineages at temperatures of 19° and 25°C but was higher in the native lineage at 32°C. Fertilization improved A max at all temperatures, and was more pronounced in the native than in the introduced lineage. Native P. australis had higher δ 13 C and water use efficiency (wue) compared to the introduced lineage. Differences in maximum photochemical efficiency of photosystem II (F v /F m ), carboxylation efficiency (V cmax ), and electron transport (J max ) were observed between lineages, and generally responded positively to treatments. Our results indicated that the native P. australis may better withstand water fluctuations and warmer temperatures than its introduced counterpart, and could contribute to diverse plant communities under warmer climate scenarios. In contrast, under cool temperatures, the introduced lineage has an advantage that could lead to further displacement of native species in water-saturated communities.

Features of phytoplankton community in the southern Caspian Sea, a decade after the invasion of Mnemiopsis leidyi

Phytoplankton study has become more significant in the Caspian Sea due to the occurrence of ecological events such as algal blooms and the introduction of the invader species(Ctenophore, Mnemiopsis leidyi ). A seasonal study was conducted to investigate the features of phytoplankton community one decade after this invasion in the Iranian coast of Caspian Sea during 2009-2010. According to the results, 195 species in eight phyla of phytoplanktons were identified. In spring, Bacillariophyta and Pyrrophyta were the dominant phyla with 40 and 29% of total abundance, respectively. In summer and winter the dominant phyla were made by Cyanophyta (92%) and Bacillariophyta (94%), respectively. The Bacillariophyta (57%) and Cyanophyta (28%) were the first and second dominant phyla in autumn . It seems that the ctenophore invasion into the Caspian Sea (due to the changes in nutrient levels and decline of phytoplankton grazers) and human's destructive activities play an effective role on phytoplankton community during the period. These changes were mainly accompanied with appearance of new and harmful species (with the ability of severe bloom making) and consequently, displacement of native species in this semi-enclosed ecosystem.

Differential susceptibility in a specialised aphidophagous ladybird, Platynaspis luteorubra (Coleoptera: Coccinellidae), facing intraguild predation by exotic and native generalist predators

The establishment of exotic generalist predators raises concern about possible domination of the invaded community and displacement of native species. In this respect, recent studies suggest that specialists are likely to be more at risk of niche displacement than generalists, thereby compromising biological control in agroecosystems. Under laboratory conditions, we examined the susceptibility of a specialised myrmecophilous ladybird, Platynaspis luteorubra Goeze, as intraguild (IG) prey of generalist native (Oenopia conglobata L. and Adalia bipunctata L.) and exotic (Harmonia axyridis Pallas) coccinellid species. We described parameters of predatory behaviour (for example, attack rate and effectiveness of antipredator defence) and their variation among predators. Furthermore, we estimated the effect of these parameters on the time to predation using a Cox proportional hazards model. We found that A. bipunctata was the most effective IG predator of P. luteorubra, with the highest rate of successful attacks; however, P. luteorubra was not very susceptibile to attack by O. conglobata or H. axyridis, and these species exhibited lower rates of successful attack and predation. Our results, together with field observations, suggest that IG predation is a factor that fosters niche specialization in P. luteorubra and decreases the realised niche of this species in central Italy. Furthermore the lower susceptibility of P. luteorubra to H. axyridis may be due to a lack of historical co-occurrence between preimmaginal stages, possibly arising from differental selection of oviposition sites.

Expansion of invasive alien plant species in the republic of Bashkortostan, the Southern Urals: Analysis of causes and ecological consequences

The causes and ecological consequences of alien plant species invasions in the Southern Urals are analyzed. Aggressive invasive species of North American origin—Ambrosia trifida L., A. psylostachya DC., Cyclachaena xanthiifolia (Nutt.) Fresen., Hordeum jubatum L., Oenothera biennis L., Bidens frondosa L., etc.—have invaded synanthropic and natural plant communities and became dominant, with their proportion varying from 10 to 99%. The biomass of these plants may reach 6 kg/m2; density, more than 1000 shoots per square meter; and seed production, up to 30000 seeds per plant, which explains their dominance in communities. The ecological hazard they pose lies in the displacement of native species, overgrowing of disturbed land areas, and allergenicity of their pollen.

Invasion by Rattus rattus into native coastal forests of south‐eastern Australia: are native small mammals at risk?

AbstractThe black rat, Rattus rattus, is an alien rodent in Australian ecosystems where niche overlap with native small mammals may lead to competition for resources and displacement of native species. In coastal habitats surrounding Jervis Bay in south‐eastern Australia, R. rattus co‐occurs with the native bush rat, Rattus fuscipes, and brown antechinus, Antechinus stuartii. Relative distributions and abundances, and fine‐scale space use suggest invasive and native rodents compete for use of space and habitat. Such competitive interactions were not evident between R. rattus and native A. stuartii, which was negatively influenced more by disturbance to habitat. Differences in rodent communities between spatially separate forests forming the northern and southern peninsulas of Jervis Bay potentially reflect symmetrical competition and differences in competitive outcomes. In southern forests, R. rattus was largely restricted to patches of disturbed forest associated with campgrounds. Competitive interference by native rodent populations inhabiting surrounding intact forests may have so far limited R. rattus colonization of these areas. In northern forests, R. rattus was the predominant rodent irrespective of disturbance, while populations of R. fuscipes were unusually low seemingly due to poor juvenile recruitment. Native individuals avoided areas frequented by adult R. rattus and given that species did not partition use of microhabitats, R. rattus most likely precluded R. fuscipes from suitable habitat and in doing so limited native populations. We discuss how natural disturbance of habitat and human activity have potentially facilitated successful invasion by R. rattus of the northern forests. Studies that manipulate rodent populations are required to support these interpretations of observed patterns.

Mechanisms of invasion resistance: competition among intertidal mussels promotes establishment of invasive species and displacement of native species

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 383:187-197 (2009) - DOI: https://doi.org/10.3354/meps07982 Mechanisms of invasion resistance: competition among intertidal mussels promotes establishment of invasive species and displacement of native species J. S. Shinen1,*, S. G. Morgan2 1Estación Costera de Investigaciones Marinas, Departamento de Ecología, Pontificia Universidad Católica de Chile, Alameda 340, Santiago, Chile 2Bodega Marine Laboratory, Department of Environmental Science and Policy, University of California Davis, PO Box 247, Bodega Bay, California 94923, USA *Email: jlshinen@bio.puc.cl ABSTRACT: Understanding interactions between invasive species and recipient communities is essential to determining whether invasive species will become established and spread. In this study, we explored the role of competition and the specific mechanisms of interaction in limiting the spread of the Mediterranean bay mussel Mytilus galloprovincialis within a Pacific Northwest invasion front. We examined the role of direct (interference) and indirect (exploitation) mechanisms of competition among M. galloprovincialis and 2 native mussels (M. trossulus and M. californianus). As the fastest-growing organisms are often competitively dominant in space-limited systems, such as rocky intertidal communities, we used changes in relative performance (growth and survival) in monocultures and polycultures to assess interactions among mussels. Performance of M. galloprovincialis was always greater than that of the 2 native species of mussels in both field and laboratory manipulations of species composition and density, indicating that interspecific competition did not strongly limit the growth or survival of the invader. Moreover, the presence of M. galloprovincialis consistently led to both reduced growth and survival of M. trossulus. Laboratory studies of mussel feeding and behavior revealed M. galloprovincialis to be a robust interference competitor. The invader restricted movement, smothered and interfered with filter feeding of the 2 native species of mussels. Rather than limiting invasion, interference competition gave M. galloprovincialis a competitive advantage over the native mussels. Our results suggest M. galloprovincialis may have contributed to the displacement of M. trossulus along much of its historic southern range. KEY WORDS: Exploitation competition · Interference competition · Mytilus · Rocky intertidal communities Full text in pdf format PreviousNextCite this article as: Shinen JS, Morgan SG (2009) Mechanisms of invasion resistance: competition among intertidal mussels promotes establishment of invasive species and displacement of native species. Mar Ecol Prog Ser 383:187-197. https://doi.org/10.3354/meps07982 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 383. Online publication date: May 14, 2009 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2009 Inter-Research.

Native predators and exotic prey –an acquired taste?

Only a small proportion of exotic species invasions give rise to hyper‐successful nuisance species, but those that do have dramatic negative impacts on ecosystems, such as the displacement of native species and disruption of native food webs. For a native predator, such changes may mean a major transformation in its resource base and a decline in its fitness. However, native predators may adapt to become more effective at feeding on exotic prey, either rapidly, via existing phenotypic plasticity, or more slowly, via natural selection. Despite a rapidly growing number of publications on the importance of species invasions as a driver of contemporary evolution in both invading and native species, we know little about how the arrival of exotic prey affects native predators. We propose that native predators could be important in regulating the long‐term dynamics of invading species and, consequently, that the overexploitation of predators could facilitate biological invasions.

Recent invasions of alien macroinvertebrates and loss of native species in the upper Rhine River, Germany

In the summers of 2003-2005 we sampled the macroinvertebrate community of the upper Rhine River at 28 locations between kilometer 351.9 and 399.5 with a dredge and a hydraulic grab from a ship, or by hand sampling. Additionally, 16 samples were obtained from the cooling water intake screens of a thermal power plant in 2003. A total of 133 species and higher taxa were identified from approximately 140,000 organisms. A total of 33 neozoa (alien) species were identified, including the first record of Chelicorophium robustum in the Rhine River. Neozoa contributed approximately 74% to the total number of organisms collected from the ship-based samples and 85% to those from the power plant cooling water. Almost 64% of all individuals from the cooling water intake belonged to the Ponto-Caspian amphipod Dikerogammarus villosus. Similarly, only 13 taxa, four native and nine alien species, numerically dominated in the ship-based samples, representing 95% and 98% of all organisms in 2003 and 2004, respectively. The nine alien species contributed 74.7% and 72.1%, respectively, to the number of organisms. Only six species occurred abundantly in the main channel of the Rhine River, five of which were neozoa: Jaera istri, Dikerogammarus villosus, Dreissena polymorpha, Chelicorophium curvispinum, and Hypania invalida. The six abundant species colonized nearshore substrates, whereas only few species were retrieved at low densities from the bottom gravel of the central shipping lane. Species diversity was generally higher and relative abundance of neozoa was lower in backwater areas than in the main river channel. Some pronounced changes in the abundance of three numerically dominant species, including the neozoa D. polymorpha and C. curvispinum, occurred between 2003 and 2004, which likely correlated with differences in water levels and temperatures. Overall, our results demonstrate that the macroinvertebrate community of the upper Rhine River has been severely altered by the invasion of several highly successful alien species and the disappearance or population decline of native species, and that these processes are still ongoing. Changes in species composition and relative numerical abundance indicate both a displacement of native species by invasive species, and a relative rapid succession in the numerical dominance of “old“ neozoa and “new“ neozoa.

Weaving Our Stories Worldwide: An indigenous approach to global economics and ecology

The Treaty of Waitangi, signed in 1840 between Māori, the indigenous people of New Zealand, and the British Crown allowed British governance in New Zealand, while affirm- ing Māori authority over their traditional territories (Orange 1995). However, the establishment of a settler dominated parliament undermined Māori authority over customary re- sources (Orange 1995). In addition an aspect of coloniza- tion that has been termed ‘ecological imperialism’ (Cros- by 1996), characterized by the widespread dispersal of animal and plant species across the world, has distorted the environmental and cultural landscape of New Zealand and other countries. Displacement of native species by in- troduced species as well as land management practices that were highly destructive to existing ecosystems (Park 1995) has resulted in a major physical reconstruction of the natural landscapes. Furthermore, the practice of tak- ing natural resources from around the world, and repack- aging and distributing them primarily by functional value or potential economic opportunity, failed to recognise the cultural and spiritual associations between indigenous people and the environment. Long established ecological and human connections have been severed in deference to these demands and this is one of the legacies of our global marketplace.

Controlling Rhododendron ponticum in the British Isles: an economic analysis

What resources should be committed to the control of invasive species? This study is based on a survey of nature conservation and forestry authorities, wildlife trusts and private landowners which investigated the extent of the ecological and economic impacts of the invasive non-native plant Rhododendron ponticum in the British Isles. There are data on 52,000 ha of land affected by R. ponticum, more than 30,000 ha of it in nature reserves. For nearly all nature reserves, displacement of native species and habitat changes were both reported. In 2001, respondents controlled 1275 ha of R. ponticum at a cost of £670,924. To test the optimality of this, we apply a model of social expenditure. The external costs of R. ponticum control are estimated from the probability that it will spread to contiguous sites and the damage done on invaded sites. These are then used to calculate the socially optimal level of expenditure on R. ponticum control, and the funding gap it identified by comparing the result with current levels of expenditure. The results suggest that a socially optimal level of control effort requires a significant increase in social funding for R. ponticum control, although the size of the increase varies between landholders.

LONG-TERM ECOSYSTEM IMPACTS OF AN INTRODUCED GRASS IN THE NORTHERN GREAT PLAINS

Introduced plants can have negative effects on native species and diversity, but their impacts on ecosystem function are less apparent. At the northern edge of the Great Plains, we examined five stands in each of undisturbed prairie, successional prairie (fields abandoned for ;50 yr that had undergone succession to native grasses), and abandoned fields of similar age planted with Agropyron cristatum, aC 3 perennial tussock grass intro- duced from northern Asia. We attributed differences between successional prairie and A. cristatum stands to the introduced species and not to cultivation. A. cristatum fields con- tained few native species, resulting in significantly lower species richness and diversity. Growth forms most similar to A. cristatum, i.e., C3 grasses, were most likely to be excluded. Soils under A. cristatum had significantly less available N, total N, and total C than soils under successional prairie. A. cristatum fields had significantly higher shoot mass than successional prairie, but root : shoot ratios in A. cristatum fields were less than half those under successional prairie, because root mass was significantly higher under native grasses. C:N ratios did not vary significantly between A. cristatum and native grasses, suggesting that the lower N and C content of soils under A. cristatum was not caused by differences in nutrient concentrations. Instead, the relatively low root mass of the introduced grass was probably responsible for decreased rates of N and C addition to the soil. Because total C was 25% less in soils under A. cristatum than under successional prairie, the planting of A. cristatum over millions of hectares of the Great Plains may have left 3.3-4.8 3 10 14 g of C in the atmosphere that would otherwise have been stored as soil organic matter by native grasses. In contrast to the large effects of A. cristatum, almost no significant dif- ferences were found between undisturbed and successional prairie. Thus, the identity of the species dominating after disturbance played a larger long-term role in determining ecosystem function than did the disturbance itself. The results suggest that the effects of this introduced species extend beyond the displacement of native species and the reduction of diversity, and include the alteration of pools and flows of energy and nutrients in the prairie ecosystem.

Imidazolinone Herbicides Improve Restoration of Great Plains Grasslands

The productivity and native species diversity of Great Plains grasslands have been substantially reduced by past management that facilitated the establishment of invasive exotic weeds and displacement of native species. Management strategies are needed to rapidly restore the productive capacity and biological diversity of these degraded grasslands. Critically important phases of the grassland restoration process are the reintroduction and establishment of native species. Weed interference is the primary constraint to successful establishment of native plants. The goal of our research is to develop strategies that use multiple technologies, including herbicides, to expedite grassland revegetation with native grasses and forbs. Imidazolinone herbicides (AC 263,333, imazapyr, and imazethapyr) were used successfully to improve establishment of native perennial grasses (big bluestem, switchgrass, little bluestem) and selected forbs (blackeyed-susan, purple prairieclover, Illinois bundleflower, trailing crownvetch, and upright prairie coneflower) on cropland and as components of a strategy to revegetate leafy spurge-infested rangeland with native tallgrasses. Imazethapyr at 70 or 110 g ai/ha applied at planting resulted in stands of big bluestem and little bluestem that were similar or superior to stands established where atrazine was applied. Seedling grasses were susceptible to imazapyr at two of three study sites. Imazapyr at 560 g ai/ha plus sulfometuron at 100 g ai/ha applied in fall was the optimum treatment for suppression of leafy spurge and exotic cool-season grasses and establishment of big bluestem and switchgrass on degraded rangeland sites. Establishment of selected forbs was improved by PRE treatment with AC 263,222 or imazethapyr at 70 g ai/ha. This research provides evidence that the imidazolinone herbicides can be important components of integrated weed management strategies designed to reverse deterioration of grasslands by reestablishing native species, improving grassland productivity, and decreasing the prevalence of exotic weeds.