scholarly journals A weed risk analytical screen to assist in the prioritisation of an invasive flora for containment

NeoBiota ◽  
2021 ◽  
Vol 66 ◽  
pp. 95-116
Author(s):  
F. Dane Panetta ◽  
Alasdair Grigg
Keyword(s):  
Risk Assessment ◽  
Risk Analysis ◽  
Plant Species ◽  
Plant Communities ◽  
Native Plant ◽  
Long Distance ◽  
Christmas Island ◽  
Invasive Flora ◽  
Closed Canopy ◽  
Scrub Forest

Prioritising weeds for control and deciding upon the type of control and its associated investment are fundamental to weed management planning. Risk analysis is central to this process, combining the activities of risk assessment, risk management and risk communication. Risk assessment methodology has a rich history, but management feasibility has typically been a secondary matter, dealt with separately or not at all. Determinants of management feasibility for weeds include the stage of invasion, weed biology, means of control and cost of weed control. Here, we describe a simple weed risk analytical screen that combines risk assessment with species traits that influence management feasibility. We consider stage of invasion, species biological/dispersal characteristics and plant community invasibility in a preliminary analysis of the risk posed by the non-native plant species on Christmas Island in the Indian Ocean. For each of 31 high-risk species considered to be ineradicable under existing funding constraints, we analyse the risk posed to two major plant communities: evergreen closed-canopy rainforest and semi-deciduous scrub forest. Weed risk ratings are combined with ratings for species-intrinsic feasibility of containment (based on a measure that combines time to reproduction with potential for long distance dispersal) to create preliminary rankings for containment specific to each community. These rankings will provide a key input for a more thorough analysis of containment feasibility – one that considers spatial distributions/landscape features, management aspects and the social environment. We propose a general non-symmetric relationship between weed risk and management feasibility, considering risk to be the dominant component of risk analysis. Therefore, in this analysis species are ranked according to their intrinsic containment feasibility within similar levels of risk to produce an initial prioritisation list for containment. Shade-tolerant weeds are of particular concern for the closed-canopy evergreen rainforest on Christmas Island, but a greater diversity of weeds is likely to invade the semi-deciduous scrub forest because of higher light availability. Nevertheless, future invasion of both communities will likely be conditioned by disturbance, both natural and anthropogenic. The plant communities of Christmas Island have undergone significant fragmentation because of clearing for phosphate mining and other purposes. With a substantial number of invasive plant species firmly established and having the potential to spread further, minimising future anthropogenic disturbance is paramount to reducing community invasibility and therefore conserving the island’s unique biodiversity.

Competition between native and non-native plants.

2020 ◽  
pp. 291-307
Author(s):  
Elizabeth M. Wandrag ◽  
◽  
Jane A. Catford ◽  
◽  
◽  
...  
Keyword(s):  
Plant Species ◽  
Plant Communities ◽  
Native Species ◽  
Abiotic Factors ◽  
Invasion Biology ◽  
Competitive Interactions ◽  
Native Plant ◽  
Native Plant Species ◽  
New Locations ◽  
Strength Of Competition

The introduction of species to new locations leads to novel competitive interactions between resident native and newly-arriving non-native species. The nature of these competitive interactions can influence the suitability of the environment for the survival, reproduction and spread of non-native plant species, and the impact those species have on native plant communities. Indeed, the large literature on competition among plants reflects its importance in shaping the composition of plant communities, including the invasion success of non-native species. While competition and invasion theory have historically developed in parallel, the increasing recognition of the synergism between the two themes has led to new insights into how non-native plant species invade native plant communities, and the impacts they have on those plant communities. This chapter provides an entry point into the aspects of competition theory that can help explain the success, dominance and impacts of invasive species. It focuses on resource competition, which arises wherever the resources necessary for establishment, survival, reproduction and spread are in limited supply. It highlights key hypotheses developed in invasion biology that relate to ideas of competition, outlines biotic and abiotic factors that influence the strength of competition and species' relative competitive abilities, and describes when and how competition between non-native and native plant species can influence invasion outcomes. Understanding the processes that influence the strength of competition between non-native and native plant species is a necessary step towards understanding the causes and consequences of biological invasions.

scholarly journals Decoupled recovery of ecological communities after reclamation

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7038 ◽  
Author(s):  
Zachary A. Sylvain ◽  
David H. Branson ◽  
Tatyana A. Rand ◽  
Natalie M. West ◽  
Erin K. Espeland
Keyword(s):  
Plant Species ◽  
Plant Communities ◽  
Oil And Gas ◽  
Plant Cover ◽  
Reference Conditions ◽  
Soil Conditions ◽  
Ecological Communities ◽  
Native Plant ◽  
Ecosystem Recovery ◽  
Nematode Communities

Grassland restoration is largely focused on creating plant communities that match reference conditions. However, these communities reflect only a subset of the biodiversity of grassland systems. We conducted a multi-trophic study to assess ecosystem recovery following energy development for oil and gas extraction in northern US Great Plains rangelands. We compared soil factors, plant species composition and cover, and nematode trophic structuring between reclaimed oil and gas well sites (“reclaims”) that comprise a chronosequence of two—33 years since reclamation and adjacent, undeveloped rangeland at distances of 50 m and 150 m from reclaim edges. Soils and plant communities in reclaims did not match those on undeveloped rangeland even after 33 years. Reclaimed soils had higher salt concentrations and pH than undeveloped soils. Reclaims had lower overall plant cover, a greater proportion of exotic and ruderal plant cover and lower native plant species richness than undeveloped rangeland. However, nematode communities appear to have recovered following reclamation. Although total and omni-carnivorous nematode abundances differed between reclaimed well sites and undeveloped rangeland, community composition and structure did not. These findings suggest that current reclamation practices recover the functional composition of nematode communities, but not soil conditions or plant communities. Our results show that plant communities have failed to recover through reclamation: high soil salinity may create a persistent impediment to native plant growth and ecosystem recovery.

scholarly journals A century of ecosystem change: human and seabird impacts on plant species extirpation and invasion on islands

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2208 ◽  
Author(s):  
Thomas K. Lameris ◽  
Joseph R. Bennett ◽  
Louise K. Blight ◽  
Marissa Giesen ◽  
Michael H. Janssen ◽  
...  
Keyword(s):  
Species Richness ◽  
Exotic Species ◽  
Plant Species ◽  
Plant Communities ◽  
Soil Depth ◽  
Rapid Change ◽  
Ecosystem Change ◽  
Native Plant ◽  
Native Plant Species ◽  
Species Cover

We used 116 years of floral and faunal records from Mandarte Island, British Columbia, Canada, to estimate the indirect effects of humans on plant communities via their effects on the population size of a surface-nesting, colonial seabird, the Glaucous-winged gull (Larus glaucescens). Comparing current to historical records revealed 18 extirpations of native plant species (32% of species historically present), 31 exotic species introductions, and one case of exotic introduction followed by extirpation. Contemporary surveys indicated that native species cover declined dramatically from 1986 to 2006, coincident with the extirpation of ‘old-growth’ conifers. Because vegetation change co-occurred with an increasing gull population locally and regionally, we tested several predictions from the hypothesis that the presence and activities of seabirds help to explain those changes. Specifically, we predicted that on Mandarte and nearby islands with gull colonies, we should observe higher nutrient loading and exotic plant species richness and cover than on nearby islands without gull colonies, as a consequence of competitive dominance in species adapted to high soil nitrogen and trampling. As predicted, we found that native plant species cover and richness were lower, and exotic species cover and richness higher, on islands with versus without gull colonies. In addition, we found that soil carbon and nitrogen on islands with nesting gulls were positively related to soil depth and exotic species richness and cover across plots and islands. Our results support earlier suggestions that nesting seabirds can drive rapid change in insular plant communities by increasing nutrients and disturbing vegetation, and that human activities that affect seabird abundance may therefore indirectly affect plant community composition on islands with seabird colonies.

scholarly journals Plant communities along the Eerste River, Western Cape, South Africa: Community descriptions and implications for restoration

Koedoe ◽  
2013 ◽  
Vol 55 (1) ◽  
Author(s):  
Clifton S. Meek ◽  
Dave M. Richardson ◽  
Ladislav Mucina
Keyword(s):  
Ecosystem Services ◽  
Plant Species ◽  
Plant Communities ◽  
Riparian Vegetation ◽  
Riparian Zone ◽  
Cape Floristic Region ◽  
Conservation Value ◽  
Western Cape ◽  
Native Plant ◽  
Alien Plant

Riparian plant communities fulfil many functions, including the provision of corridors linking protected areas and other zones of high conservation value. These habitats across much of South Africa’s Cape Floristic Region, especially in the lowlands, have been heavily impacted and degraded by human activities. There is increasing interest in the restoration of degraded riparian zones and the ecosystem services they provide to enhance the conservation value of landscapes. Previous studies of riparian vegetation in the Cape Floristic Region focused on pristine headwater systems, and little is known about human-impacted communities that make up most of the riparian vegetation in downstream areas. More information is needed on the composition of these plant communities to establish a baseline for management intervention. The riparian zone of the Eerste River in South Africa’s Western Cape province provides a good opportunity to study the features of riparian vegetation along the entire gradient, from pristine vegetation in a protected area through different levels of human-mediated degradation. Riparian vegetation was surveyed in 150 plots along the entire length of the Eerste River (ca. 40 km). Data were analysed using the vegetation classification and analysis software package JUICE. Final groupings were plotted onto a two-dimensional detrended correspondence analysis plane to check the position of the communities in the reduced multidimensional space. Ten distinct plant communities were identified, including several novel communities dominated by alien plant species. Descriptions of each plant community are presented. Diagnostic, constant and dominant species are listed and the major structural and ecological characteristics of each community are described.Conservation implications: Major changes to hydrological and soil properties, nutrient dynamics and disturbance regimes and plant species composition along sections of the riparian zone mean that restoration of many of these habitats to their historic condition is not feasible. However, several native plant species that provide key ecosystem services persist in and adjacent to transformed communities, offering substantial opportunities for restoration to achieve certain goals.

scholarly journals A century of ecosystem change: human and seabird impacts on plant species extirpation and invasion on islands

2016 ◽  
Author(s):  
Thomas K Lameris ◽  
Joseph R Bennett ◽  
Louise K Blight ◽  
Marissa Giesen ◽  
Michael H Janssen ◽  
...  
Keyword(s):  
Species Richness ◽  
Exotic Species ◽  
Plant Species ◽  
Plant Communities ◽  
Soil Depth ◽  
Rapid Change ◽  
Ecosystem Change ◽  
Native Plant ◽  
Native Plant Species ◽  
Species Cover

We used 116-years of floral and faunal records from Mandarte Island, British Columbia, Canada, to estimate the indirect effects of humans on plant communities via their effects on the population size of a surface-nesting, colonial seabird, the Glaucous-winged gull (Larus glaucescens). Comparing current to historical records revealed 18 extirpations of native plant species (32% of species historically present), 31 exotic species introductions, and one case of exotic introduction followed by extirpation. Contemporary surveys indicated that native species cover declined dramatically from 1986 to 2006, coincident with the extirpation of ‘old-growth’ conifers. Because vegetation change co-occurred with an increasing gull population locally and regionally, we also tested predictions from the hypothesis that the presence and activities of seabirds help to explain those changes. Specifically, we predicted we would observe high nutrient loading and exotic plant species richness and cover on nearby islands with versus without gull colonies as a consequence of competitive dominance in species adapted to high soil nitrogen and trampling. As predicted, we found that native plant species cover and richness were lower, and exotic species cover and richness higher, on islands with versus without gull colonies. In addition, we found that soil carbon and nitrogen on islands with nesting gulls were positively related to soil depth and exotic species richness and cover across plots and islands. Our results suggest that gulls have the potential to drive rapid change in insular plant communities by increasing nutrients and disturbing vegetation. Because human activities have contributed to long-term change in gull populations, our results further suggest compelling, indirect links between human management decisions and plant community composition on islands of the Georgia Basin.

scholarly journals Adaptive foraging behaviour of individual pollinators and the coexistence of co-flowering plants

2014 ◽  
Vol 281 (1776) ◽  
pp. 20132437 ◽  
Author(s):  
Zhiyuan Song ◽  
Marcus W. Feldman
Keyword(s):  
Population Dynamics ◽  
Plant Species ◽  
Plant Communities ◽  
Foraging Behaviour ◽  
Adaptive Behaviour ◽  
Native Plant ◽  
Flower Constancy ◽  
Individual Level ◽  
The Individual ◽  
Adaptive Foraging

Although pollinators can play a central role in determining the structure and stability of plant communities, little is known about how their adaptive foraging behaviours at the individual level, e.g. flower constancy, structure these interactions. Here, we construct a mathematical model that integrates individual adaptive foraging behaviour and population dynamics of a community consisting of two plant species and a pollinator species. We find that adaptive foraging at the individual level, as a complementary mechanism to adaptive foraging at the species level, can further enhance the coexistence of plant species through niche partitioning between conspecific pollinators. The stabilizing effect is stronger than that of unbiased generalists when there is also strong competition between plant species over other resources, but less so than that of multiple specialist species. This suggests that adaptive foraging in mutualistic interactions can have a very different impact on the plant community structure from that in predator–prey interactions. In addition, the adaptive behaviour of individual pollinators may cause a sharp regime shift for invading plant species. These results indicate the importance of integrating individual adaptive behaviour and population dynamics for the conservation of native plant communities.

The long-term ability of phosphite to control Phytophthora cinnamomi in two native plant communities of Western Australia

2001 ◽  
Vol 49 (6) ◽  
pp. 761 ◽  
Author(s):  
K. M. Tynan ◽  
C. J. Wilkinson ◽  
J. M. Holmes ◽  
B. Dell ◽  
I. J. Colquhoun ◽  
...  
Keyword(s):  
Plant Species ◽  
Plant Communities ◽  
Western Australia ◽  
Foliar Application ◽  
Phytophthora Cinnamomi ◽  
Native Plant ◽  
In Planta ◽  
Eucalyptus Marginata ◽  
Application Rates ◽  
The Impact

This study examined the ability of foliar applications of the fungicide phosphite to contain colonisation of Phytophthora cinnamomi in a range of plant species growing in natural plant communities in the northern sandplain and jarrah (Eucalyptus marginata) forest of south-western Australia. Wound inoculation of plant stems with P. cinnamomi was used to determine the efficacy of phosphite over time after application. Colonisation by P. cinnamomi was reduced for 5–24 months after phosphite was applied, depending on the concentration of phosphite used, plant species treated and the time of phosphite application. Plant species within and between plant communities varied considerably in their ability to take up and retain phosphite in inoculated stems and in the in planta concentrations of phosphite required to contain P. cinnamomi. As spray application rates of phosphite increased from 5 to 20 g L–1, stem tissue concentrations increased, as did the ability of a plant species to contain P. cinnamomi. However, at application rates of phosphite above 5 g L–1 phytotoxicity symptoms were obvious in most species, with some plants being killed. So, despite 10 and 20 g L–1 of phosphite being more effective and persistent in controlling P. cinnamomi, these rates are not recommended for application to the plant species studied. The results of this study indicate that foliar application of phosphite has considerable potential in reducing the impact of P. cinnamomi in native plant communities in the short-term. However, in order to maintain adequate control, phosphite should be sprayed every 6–12 months, depending on the species and/or plant community.

scholarly journals Establishing sustainable roadside vegetation communities of high botanical and aesthetic value: the basic concept statement and experimental justification

2019 ◽  
Vol 64 (2) ◽  
pp. 238-254
Author(s):  
I. P. Voznyachuk ◽  
N. B. Vlasava ◽  
I. M. Stepanovich ◽  
A. T. Godneva ◽  
V. N. Reshetnikov
Keyword(s):  
Plant Species ◽  
Plant Communities ◽  
Management Practices ◽  
Native Plant ◽  
Aesthetic Value ◽  
Native Plant Species ◽  
Native Flora ◽  
Roadside Vegetation ◽  
The Republic ◽  
Mowing Regime

The basic principles for the development of a new greening system for the region of Belarus aimed at creation and restoration of sustainable roadside plant communities of high botanical and aesthetic value are formulated on the basis of the use of conservation, restoration and “incorporation” methods of flowering native plant species, characteristic of a particular region. The statements of the concept are developed and recommended for roadways and highways in the Republic of Belarus and tested on the model site between the city of Myadel and the resort village of Naroch of Highway P28. Roadside vegetation management practices in other countries as well as our research has shown that along the investigated roads there is a high adaptive potential of native flora; by changing the mowing regime, sustainable plant communities can be established while enhancing the aesthetics and expressiveness of key elements of the landscape of the roadsides. The implementation of the strategy for each geobotanical region depends on the development of an assortment of native plant species that can be used for the greening of roadside areas. This should be done by taking into account their geobotanical and edaphic features, creation of a seed bank for grass mixtures, the formation of natural genetic reserves (field banks) of meadow flora to conserve the local and overall ecosystem and genetic balance. For examples, the atlas of plants “Roadside flowers” developed for the National Park “Narochansky” is recommended for use in roadsides (verges) greening within the boundaries of the Oshmyany– Minsk geobotanical district. To expand the use of gained positive experience on increasing the biodiversity of roadside ecosystems and reducing the cost of their maintenance, it is desirable to implement this strategy for the entire road network of Belarus, which will require adjustment in technologies for managing roadside ecosystems, based on priorities of conservation, restoration and formation of native plant communities, including meadows and wetlands.

scholarly journals The effects of local filtering processes on the structure and functioning of native plant communities in experimental urban habitats

2021 ◽  
Author(s):  
Dorothy Borowy ◽  
Chris Swan
Keyword(s):  
Plant Species ◽  
Functional Diversity ◽  
Plant Communities ◽  
Native Species ◽  
Urban Environments ◽  
Functional Composition ◽  
Native Plant ◽  
Urban Habitats ◽  
Over Time ◽  
Local Filtering

Despite a growing literature-base devoted to documenting biodiversity patterns in cities, little is known about the processes that influence these patterns, and whether they are consistent over time. In particular, numerous studies have identified the capacity of cities to host a rich diversity of plant species. This trend, however, is driven primarily by introduced species, which comprise a large proportion of the urban species pool relative to natives. Using an experimental common garden study, we assessed the relative influence of local assembly processes (i.e., soil environmental filtering and competition from spontaneous urban species) on the taxonomic and functional diversity of native plant communities sampled over four seasons in 2016-2018. Taxonomic and functional diversity exhibited different responses to local processes, supporting the general conclusion that species- and trait-based measures of biodiversity offer distinct insights into community assembly dynamics. Additionally, we found that neither soil nor competition from spontaneous urban species influenced taxonomic or functional composition of native species. Functional composition, however, did shift strongly over time and was driven by community-weighted mean differences in both measured traits (maximum height, Hmax; specific leaf area, SLA; leaf chlorophyll a fluorescence, chl a) and the relative proportions of different functional groups (legumes, annual and biennial-perennial species, C4 grasses, and forbs). In contrast, taxonomic composition only diverged between early and late seasons. Overall, our results indicate that native species are not only capable of establishing and persisting in vacant urban habitats, they can functionally respond to local filtering pressures over time. This suggests that regional dispersal limitation may be a primary factor limiting native species in urban environments. Thus, future regreening and management plans should focus on enhancing the dispersal potential of native plant species in urban environments, in order to achieve set goals for increasing native species diversity and associated ecosystem services in cities.

scholarly journals Effects of the invasive plant Xanthium strumarium on diversity of native plant species: A competitive analysis approach in North and Northeast China

PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0228476
Author(s):  
Mazher Farid Iqbal ◽  
Ming-Chao Liu ◽  
Aafia Iram ◽  
Yu-Long Feng
Keyword(s):  
Species Richness ◽  
Plant Species ◽  
Plant Communities ◽  
Northeast China ◽  
Invasive Plant ◽  
Diversity Index ◽  
Diversity Indices ◽  
Xanthium Strumarium ◽  
Native Plant ◽  
Native Plant Species

Xanthium strumarium is native to North America and now has become one of the invasive alien species (IAS) in China. In order to detect the effects of the invader on biodiversity and evaluate its suitable habitats and ecological distribution, we investigated the abundance, relative abundance, diversity indices, and the number of the invasive and native plants in paired invaded and non-invaded quadrats in four locations in North and Northeast China. We also analyzed the effects of monthly mean maximum and minimum temperatures, relative humidity (%), and precipitations (mm). Strong positive significant (P < 0.01) correlation and maximum interspecific competition (41%) were found in Huailai between invaded and non-invaded quadrats. Shannon’s Diversity Index showed that non-invaded plots had significantly (P < 0.05) more diversified species than invaded ones. The significant (P < 0.05) Margalef’s Richness Index was found in Huailai and Zhangjiakou in non-invaded recorded heterogeneous nature of plant communities. Similarly, significant (P < 0.05) species richness found in Huailai and Zhangjiakou in non-invaded quadrats compared to invaded ones. Maximum evenness of Setaria feberi (0.47, 0.37), Seteria viridis (0.43) found in Fushun and Zhangjiakou recorded more stable in a community compared to other localities. Evenness showed positive relationship of Shannon Entropy within different plant species. The higher dissimilarity in plant communities found in Huailai (87.06%) followed by Yangyuan (44.43%), Zhangjiakou (40.13%) and Fushun (29.02%). The significant (P < 0.01) value of global statistics R (0.943/94.3%) showed high species diversity recorded in Huailai followed by Zhangjiakou recorded by non-metric multidimensional scaling and analysis of similarity between invaded and non-invaded plots. At the end it was concluded that the diversity indices reduced significantly (P < 0.05) in invaded quadrats indicated that native plant species become less diverse due to X. strumarium invasion. The degrees of X. strumarium invasion affected on species richness resulted to reduce diversity indices significantly in invaded quadrats.

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