scholarly journals Non-Native Herbivores Promote Plant Invasions Away From Mountain Roads in the Andes

2021 ◽  
Author(s):  
Valeria Aschero ◽  
Agustina Barros ◽  
Lorena Bonjour ◽  
Ana Mazzolari ◽  
Martín Pérez Sosa ◽  
...  
Keyword(s):  
Protected Areas ◽  
Native Species ◽  
Plant Invasions ◽  
Natural Vegetation ◽  
Livestock Grazing ◽  
Native Plant ◽  
The Road ◽  
The Andes ◽  
The Impact

Abstract While the role of environmental filters, usually described by elevation as proxy, and anthropogenic disturbance as drivers of non-native plant diversity and abundance in mountains have been extensively studied, the impact of herbivores are less explored. Livestock grazing can facilitate the introduction of non-native species by seed dispersal and reduce biotic resistance due to consumption and trampling of native plants, even in the highest protected areas in the Andes. We here explored the effects of elevation, livestock and distance to the road on non-native and native plant distributions. Our results confirm the largely negative relationship of non-native plant richness and cover with elevation, with a peak in richness and cover at low to intermediate elevations. Similarly, we show a strong decline in non-native richness with increasing distance to the road, especially at low elevations, accompanied by a strong negative effect of roads on native species richness. Most importantly, however, we show that the presence of non-native herbivores greatly increases the cover of non-native species away from the roadside, identifying herbivore disturbance as a potential catalyst of non-native plant invasion into natural vegetation of high-Andean protected areas. Our results confirm the often-shown role of disturbance as driver of plant invasions in mountains, yet highlight the interactive effects of disturbance by roads and herbivory: roads funnel non-native species towards higher elevations, while non-native herbivores can promote non-native plant success away from the roadside and into the natural vegetation. Hence, regulating soil and non-native herbivory disturbance is important for minimizing plant invasions at high elevation in the Arid Andes.

Plant invasions: the role of biotic interactions - an overview.

2020 ◽  
pp. 1-25
Author(s):  
Anna Traveset ◽  
David M. Richardson
Keyword(s):  
Plant Invasion ◽  
Native Species ◽  
Biotic Resistance ◽  
Biotic Interactions ◽  
Invasion Biology ◽  
Plant Invasions ◽  
Ecological Communities ◽  
Native Plant ◽  
Common Garden Experiments

Abstract Diverse biotic interactions between non-native plant species and other species from all taxonomic groups are crucial mediators of the dynamics of plant invasions. This chapter reviews the key hypotheses in invasion ecology that invoke biotic interactions to explain aspects of plant invasion dynamics. We examine the historical context of these hypotheses and assess the evidence for accepting or rejecting their predictions. Most hypotheses invoke antagonistic interactions, mainly competition, predation, herbivory interactions and the role of pathogens. Only in the last two decades have positive (facilitative/mutualistic) interactions been explicitly included in invasion biology theory (as in ecological theory in general). Much information has accumulated in testing hypotheses relating to biotic resistance and Enemy Release Theory, although many of the emerging generalizations are still contentious. There is growing consensus that other drivers of plant invasion success, such as propagule pressure and disturbance, mediate the outcome of biotic interactions, thereby complicating our ability to make predictions, but these have rarely been assessed in both native and adventive ranges of non-native invasive species. It is also widely acknowledged that biogeographic comparisons, more than common garden experiments, are needed to shed light on many of the contradictory results. Contrasting findings have also emerged in exploring the roles of positive interactions. Despite strong evidence that such interactions are crucial in many communities, more work is needed to elucidate the factors that influence the relative importance of positive and negative interactions in different ecosystems. Different types of evidence in support of invasional meltdown have emerged for diverse habitats and across spatial scales. In light of increasing evidence that biotic indirect effects are crucial determinants of the structure, dynamics and evolution of ecological communities, both direct and indirect interactions involving native and non-native species must be considered to determine how they shape plant invasion patterns and the ecological impacts of non-native species on recipient communities. Research that examines both biotic interactions and the factors that mediate their strength and alter interaction outcomes is needed to improve our ability to predict the effects of novel interactions between native and non-native species, and to envisage how existing invaded communities will respond to changing environmental conditions. Many opportunities exist for manipulating biotic interactions as part of integrated control strategies to reduce the extent, density and impacts of non-native plant invasions. These include the introduction of species from the native range of the non-native plant for biological control, diverse manipulations of plant - herbivore interactions and many types of interaction to enhance biotic resistance and steer vegetation recovery following non-native plant control.

scholarly journals Hiking trails as conduits for the spread of non-native species in mountain areas

2019 ◽  
Vol 22 (3) ◽  
pp. 1121-1134 ◽  
Author(s):  
Rebecca Liedtke ◽  
Agustina Barros ◽  
Franz Essl ◽  
Jonas J. Lembrechts ◽  
Ronja E. M. Wedegärtner ◽  
...  
Keyword(s):  
Native Species ◽  
Control Plant ◽  
Plant Invasions ◽  
Native Plant ◽  
Mountain Areas ◽  
Central Chile ◽  
Hiking Trails ◽  
Local Plant ◽  
Southern Central ◽  
Recreational Use

AbstractRoadsides are major pathways of plant invasions in mountain regions. However, the increasing importance of tourism may also turn hiking trails into conduits of non-native plant spread to remote mountain landscapes. Here, we evaluated the importance of such trails for plant invasion in five protected mountain areas of southern central Chile. We therefore sampled native and non-native species along 17 trails and in the adjacent undisturbed vegetation. We analyzed whether the number and cover of non-native species in local plant assemblages is related to distance to trail and a number of additional variables that characterize the abiotic and biotic environment as well as the usage of the trail. We found that non-native species at higher elevations are a subset of the lowland source pool and that their number and cover decreases with increasing elevation and with distance to trails, although this latter variable only explained 4–8% of the variation in the data. In addition, non-native richness and cover were positively correlated with signs of livestock presence but negatively with the presence of intact forest vegetation. These results suggest that, at least in the region studied, hiking trails have indeed fostered non-native species spread to higher elevations, although less efficiently than roadsides. As a corollary, appropriate planning and management of trails could become increasingly important to control plant invasions into mountains in a world which is warming and where visitation and recreational use of mountainous areas is expected to increase.

Assessing the invasion threat of non-native plant species in protected areas using Herbarium specimen and ecological survey data. A case study in two rangeland bioregions in Queensland

2017 ◽  
Vol 39 (1) ◽  
pp. 85
Author(s):  
Michael R. Ngugi ◽  
Victor John Neldner
Keyword(s):  
Protected Areas ◽  
Survey Data ◽  
Native Species ◽  
Native Plants ◽  
Herbarium Specimen ◽  
Native Plant ◽  
Economic Productivity ◽  
Ecological Survey ◽  
National Significance

Naturalised non-native plants that become invasive pose a significant threat to the conservation of biodiversity in protected areas (areas dedicated and managed for long-term conservation of nature), economic productivity of agricultural businesses, and societal impacts including community, culture infrastructure and health. Quantifying the spread, potential dominance and invasion threat of these species is fundamental to effective eradication and development of threat mitigation policy. But this is often hampered by the lack of comprehensive data. This study used existing ecological survey data from 2548 sites and 64 758 Herbarium specimen records to document the status and abundance of non-native plants in two case study bioregions, Cape York Peninsula (CYP) and the Desert Uplands (DEU) in Queensland covering a total area of 186 697 km2. There were 406 non-native species in the CYP, 186 (45.6%) of which are known environmental weeds and 159 non-natives in DEU, of which 69 (43.5%) are environmental weeds. Inside the protected areas, there were 98 species of environmental weeds in CYP, 27 of which are listed as weeds of State significance (Weeds of National Significance (WONS), Queensland declared and non-declared pest plants categories). In DEU, there were 18 environmental weeds inside protected areas and none of them was listed as a weed of State significance. Non-native species that recorded foliage cover dominance in the ecological site data are generally recognised as environmental weeds in Queensland. The threat of weeds from outside of protected areas was serious, with 41 weeds of State significance found in CYP, five of which are WONS, and 25 weeds of State significance found in DEU, 10 of which are WONS.

Plant invasions: the role of biotic interactions

2020 ◽  
Keyword(s):  
Introduced Species ◽  
Plant Invasion ◽  
Native Species ◽  
Native Plants ◽  
Biotic Interactions ◽  
Plant Invasions ◽  
Invasion Dynamics ◽  
Experimental Approaches ◽  
Antagonistic Interactions

Abstract This book contains 23 chapters divided into seven parts. Part I reviews the key hypotheses in invasion ecology that invoke biotic interactions to explain aspects of plant invasion dynamics; and reviews models, theories and hypotheses on how invasion performance and impact of introduced species in recipient ecosystems can be conjectured according to biotic interactions between native and non-native species. Part II deals with positive and negative interactions in the soil. Part III discusses mutualistic interactions that promote plant invasions. Part IV describes antagonistic interactions that hinder plant invasions, while part V presents the consequences of plant invasions for biotic interactions among native species. In part VI, novel techniques and experimental approaches in the study of plant invasions are shown. In the last part, biotic interactions and the management of ecosystems invaded by non-native plants are discussed.

Individuals matter: predicting koala road crossing behaviour in south-east Queensland

2018 ◽  
Vol 40 (1) ◽  
pp. 67 ◽  
Author(s):  
C. E. Dexter ◽  
R. G. Appleby ◽  
J. Scott ◽  
J. P. Edgar ◽  
D. N. Jones
Keyword(s):  
Mitigation Strategies ◽  
Urban Landscapes ◽  
Phascolarctos Cinereus ◽  
The Road ◽  
Crossing Structures ◽  
Dramatic Decline ◽  
Road Mitigation ◽  
The Impact ◽  
Road Crossing

The ability to predict the frequency with which koalas (Phascolarctos cinereus) cross roads is an important step in developing mitigation strategies aimed at maintaining metapopulation viability for this species. In south-east Queensland, Australia, rapid urban development, including fragmentation and vehicle-related mortality, has contributed to a dramatic decline in local koala populations. Assessment of wildlife crossing structures that mitigates the impact of roads demonstrates these to be beneficial for many species. However, building enough structures to enable animals to move freely across impacted landscapes may be prohibitive in complex urban landscapes. The focus for this study was to consider the role of differing characteristics for species at risk. We examined the frequency of road crossings by individual koalas among six subpopulations in south-east Queensland. We explored the influence of potential predictor variables including: age, sex, and distance from roads. We established that road crossings were limited to a subset of individuals, with only 18 of 51 (~35%) koalas studied ever crossing a road. We found that koalas were disproportionately more likely to cross a road if they had initially been found within a distance of 100 m of that road. Males were more likely to cross roads than females, as were koalas aged less than five years. We suggest that successful wildlife road mitigation can be improved by better understanding the road-crossing behaviour of species such as the koala.

Factors influencing pasture productivity in Atlantic Canada

1993 ◽  
Vol 73 (4) ◽  
pp. 699-713 ◽  
Author(s):  
Y. A. Papadopoulos ◽  
H. T. Kunelius ◽  
A. H. Fredeen
Keyword(s):  
Festuca Arundinacea ◽  
Native Species ◽  
Phleum Pratense ◽  
Gastrointestinal Parasites ◽  
Livestock Grazing ◽  
Grass Species ◽  
Atlantic Canada ◽  
The Impact ◽  
Grazing Livestock ◽  
Pasture Productivity

Most pastures in Atlantic Canada are classified as permanent and contain primarily native species. Well-managed native swards have the potential of supporting profitable animal output. Productive cultivars of cool-season perennial grass species such as timothy (Phleum pratense L.), orchardgrass (Dactylis glomerata L.), tall fescue (Festuca arundinacea Schreb.), reed canarygrass (Phalaris arundinacea L.) and legumes such as white clover can increase pasture productivity in the region and ameliorate seasonal fluctuations in dry matter yield associated with native swards. Improved swards gradually revert to native species, partly because forage cultivars and mixtures are not assessed for persistence under grazing.Soil acidity and deficiencies in soil nutrients were shown to reduce herbage yield, legume content of the grazed swards and mineral content of the herbage, all of which may adversely affect livestock performance. High concentrations of K, observed in swards heavily fertilized with N, are likely to cause problems in the metabolism of Ca and Mg in lactating ruminant livestock grazing such swards.Supplemental pasture crops, including annual ryegrass (Lolium multiflorum Lam.) and Brassica species, extend the productive grazing season from approximately 4 to 7 mo, and permit the production of large quantities of biomass close to the barn.Rotational grazing and forward creep-grazing techniques at high stocking rates can improve the number of animal grazing days and average daily gains. Previous experience with grazing and exposure to pasture species before and during weaning appear to influence grazing behavior and species preference of newly weaned livestock. The use of previous grazing experience may help create the desired pasture sward or improve the efficiency of sward utilization by the grazing animal. The high rainfall climate of the Atlantic region, which promotes good herbage production, also encourages heavy and prolonged infestations of infective free-living stages of gastrointestinal parasites on pastures. Permanent pasture is the main source of initial herd infection, which then spreads to newly seeded pastures. Strategic treatments of grazing livestock with anthelmintic drugs are recommended to minimize the impact of these parasites on the productivity of grazing livestock in this region. Key words: Pasture, Atlantic Canada, productivity, grazing management, fertility management, Brassica spp., grasses, legumes

Effect of Aqueous Leaf Extract of Parthenium hysterophorus L. on the Germination and Shoot Growth of Two Native Species

2013 ◽  
Vol 726-731 ◽  
pp. 4348-4351 ◽  
Author(s):  
Gang Hu ◽  
Zhong Hua Zhang ◽  
Bao Qing Hu
Keyword(s):  
Seed Germination ◽  
Native Species ◽  
Shoot Growth ◽  
Southern China ◽  
Parthenium Hysterophorus ◽  
Native Plant ◽  
Leaf Extracts ◽  
Allelopathic Potential ◽  
Plantago Asiatica ◽  
The Impact

In order to evaluate the allelopathic potential of an exotic invasive weed,Parthenium hysterophorusL., the effect of different concentrations of aqueous extracts (5%, 25%, 50%, 75% and 100%) prepared from leaves ofP. hysterophoruswere studied on the seed germination and seedling shoot growth of two common native herbs,Plantago asiaticaL. andYoungia japonica(L.) DC., through laboratory bioassays. The aqueous leaf extracts at the concentrations of 25%, 75% and 100% significantly inhibited the seed germination and seedling shoot growth of two target species. There was complete failure of seed germination ofY. japonicain 75% and 100% aqueous leaf extracts. The inhibitory effect increased with increasing extract concentration. These results suggested that allelopathy may play a role in the impact ofP. hysterophorusinvasion on native plant recruitment of invaded communities in southern China.

scholarly journals Herbivory may promote a non-native plant invasion at low but not high latitudes

2019 ◽  
Vol 124 (5) ◽  
pp. 819-827 ◽  
Author(s):  
Xinmin Lu ◽  
Minyan He ◽  
Saichun Tang ◽  
Yuqing Wu ◽  
Xu Shao ◽  
...  
Keyword(s):  
Invasive Species ◽  
Native Species ◽  
Invasive Plant ◽  
Field Survey ◽  
Common Garden ◽  
Middle Latitude ◽  
Plant Invasions ◽  
Alternanthera Philoxeroides ◽  
Native Plant ◽  
Low Latitude

Abstract Background and Aims The strengths of biotic interactions such as herbivory are expected to decrease with increasing latitude for native species. To what extent this applies to invasive species and what the consequences of this variation are for competition among native and invasive species remain unexplored. Here, herbivore impacts on the invasive plant Alternanthera philoxeroides and its competition with the native congener A. sessilis were estimated across latitudes in China. Methods An common garden experiment spanning ten latitudinal degrees was conducted to test how herbivore impacts on A. philoxeroides and A. sessilis, and competition between them change with latitude. In addition, a field survey was conducted from 21°N to 36.8°N to test whether A. philoxeroides invasiveness changes with latitude in nature as a result of variations in herbivory. Key Results In the experiment, A. sessilis cover was significantly higher than A. philoxeroides cover when they competed in the absence of herbivores, but otherwise their cover was comparable at low latitude. However, A. philoxeroides cover was always higher on average than A. sessilis cover at middle latitude. At high latitude, only A. sessilis emerged in the second year. Herbivore abundance decreased with latitude and A. philoxeroides emerged earlier than A. sessilis at middle latitude. In the field survey, the ratio of A. philoxeroides to A. sessilis cover was hump shaped with latitude. Conclusion These results indicate that herbivory may promote A. philoxeroides invasion only at low latitude by altering the outcome of competition in favour of the invader and point to the importance of other factors, such as earlier emergence, in A. philoxeroides invasion at higher latitudes. These results suggest that the key factors promoting plant invasions might change with latitude, highlighting the importance of teasing apart the roles of multiple factors in plant invasions within a biogeographic framework.

scholarly journals Metabolomics of Myrcia bella Populations in Brazilian Savanna Reveals Strong Influence of Environmental Factors on Its Specialized Metabolism

Molecules ◽  
2020 ◽  
Vol 25 (12) ◽  
pp. 2954
Author(s):  
Luiz Leonardo Saldanha ◽  
Pierre-Marie Allard ◽  
Adlin Afzan ◽  
Fernanda Pereira de Souza Rosa de Melo ◽  
Laurence Marcourt ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Native Species ◽  
Abiotic Factors ◽  
Soil Nutrient ◽  
Brazilian Savanna ◽  
Soil Conditions ◽  
Native Plant ◽  
Specialized Metabolism ◽  
Temperature Radiation ◽  
The Impact

Environmental conditions influence specialized plant metabolism. However, many studies aiming to understand these modulations have been conducted with model plants and/or under controlled conditions, thus not reflecting the complex interaction between plants and environment. To fully grasp these interactions, we investigated the specialized metabolism and genetic diversity of a native plant in its natural environment. We chose Myrcia bella due to its medicinal interest and occurrence in Brazilian savanna regions with diverse climate and soil conditions. An LC-HRMS-based metabolomics approach was applied to analyze 271 samples harvested across seven regions during the dry and rainy season. Genetic diversity was assessed in a subset of 40 samples using amplified fragment length polymorphism. Meteorological factors including rainfall, temperature, radiation, humidity, and soil nutrient and mineral composition were recorded in each region and correlated with chemical variation through multivariate analysis (MVDA). Marker compounds were selected using a statistically informed molecular network and annotated by dereplication against an in silico database of natural products. The integrated results evidenced different chemotypes, with variation in flavonoid and tannin content mainly linked to soil conditions. Different levels of genetic diversity and distance of populations were found to be correlated with the identified chemotypes. These observations and the proposed analytical workflow contribute to the global understanding of the impact of abiotic factors and genotype on the accumulation of given metabolites and, therefore, could be valuable to guide further medicinal exploration of native species.

Conservation of the Grassy White Box Woodlands: Relative Contributions of Size and Disturbance to Floristic Composition and Diversity of Remnants

1995 ◽  
Vol 43 (4) ◽  
pp. 349 ◽  
Author(s):  
SM Prober ◽  
KR Thiele
Keyword(s):  
Species Richness ◽  
Native Species ◽  
Species Abundance ◽  
Livestock Grazing ◽  
General Character ◽  
Native Plant ◽  
Weed Invasion ◽  
Total Species Richness ◽  
Eastern Australia ◽  
Native Species Richness

Before European settlement, grassy white box woodlands were the dominant vegetation in the east of the wheat-sheep belt of south-eastern Australia. Tree clearing, cultivation and pasture improvement have led to fragmentation of this once relatively continuous ecosystem, leaving a series of remnants which themselves have been modified by livestock grazing. Little-modified remnants are extremely rare. We examined and compared the effects of fragmentation and disturbance on the understorey flora of woodland remnants, through a survey of remnants of varying size, grazing history and tree clearing. In accordance with fragmentation theory, species richness generally increased with remnant size, and, for little-grazed remnants, smaller remnants were more vulnerable to weed invasion. Similarly, tree clearing and grazing encouraged weed invasion and reduced native species richness. Evidence for increased total species richness at intermediate grazing levels, as predicted by the intermediate disturbance hypothesis, was equivocal. Remnant quality was more severely affected by grazing than by remnant size. All little-grazed remnants had lower exotic species abundance and similar or higher native species richness than grazed remnants, despite their extremely small sizes (< 6 ha). Further, small, littlegrazed remnants maintained the general character of the pre-European woodland understorey, while grazing caused changes to the dominant species. Although generally small, the little-grazed remnants are the best representatives of the pre-European woodland understorey, and should be central to any conservation plan for the woodlands. Selected larger remnants are needed to complement these, however, to increase the total area of woodland conserved, and, because most little-grazed remnants are cleared, to represent the ecosystem in its original structural form. For the maintenance of native plant diversity and composition in little-grazed remnants, it is critical that livestock grazing continues to be excluded. For grazed remnants, maintenance of a site in its current state would allow continuation of past management, while restoration to a pre-European condition would require management directed towards weed removal, and could take advantage of the difference noted in the predominant life-cycle of native (perennial) versus exotic (annual or biennial) species.

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