Ecology and management of alien annual grasses in the deserts of southwest North America
John H. Brock
College of Integrative Sciences and Arts, Arizona State University Polytechnic, Mesa, Arizona, USA
Seven alien invasive annual grasses are found in the southwest region of the United States and northern Mexico. All of these annual grasses germinate with autumn and winter rainfall. They begin rapid growth as temperatures increase in February and March and reach peak standing crop late in the spring, either May or June depending on their distribution by elevation. When in the vegetative mode, they are consumed by grazing animals, but when they produce seed heads, grazing essentially ceases. Their seeds are easily dispersed and in general have about a three-year life in the seed bank. All of these species were introduced from Europe/Asia. The dominant genus is Bromus and includes: Bromus rubens syn. B. madritensis (red bromegrass), B. tectorum (downy bromegrass), B. carthicus (rescue grass), B. japonicus (Japanese bromegrass), and B. diandrus (ripgut brome). Schimus barbatus (Mediterranean grass) a short lived small grass is found primarily in the warm deserts. Avena fatua (wild oats) provides good forage in the spring and is currently found at elevations of less than 1,500 m. All of these grasses compete with native vegetation and can promote wild fires. Management of these species includes targeted grazing by domestic livestock, prescribed burning, mowing and the use of both pre and post emergence herbicides.
Parks as sources of invasion and refugia for threatened native species
Jan Pergl, Martin Vojík, Petr Petřík, Jiří Sádlo, Matěj Man and Petr Pyšek
Institute of Botany, Czech Academy of Sciences, Zámek 1, 252 43 Průhonice, Czech Republic
Ornamental plants and human made habitats are traditionally studied separately from natural or semi-natural sites. Chateau parks act as sources of new alien plants recruiting from introduced ornamentals escaping from cultivation, but these habitats can also be threatened by invasive plants. To assess the role that chateau parks play in the invasion process, we studied parks as sources of new neophytes and as an environment providing protection for already present alien species.
We present results of a survey in 98 parks in the Czech Republic, that were located in urban areas, chateaus, palace gardens and countryside parks, in various landscape and socioeconomic contexts. Our study aims at (i) providing comprehensive information on spontaneously spreading alien taxa planted in parks or arriving from their surroundings, (ii) analysing their diversity, status, frequency and abundance, (iii) correlating the species data with socioeconomic factors and management practices used in the parks, and (iv) assessing the invasion potential of the taxa.
Our results show that (i) the number of escaping invaders and their population sizes are not as high as we expected, with many cultivated taxa in the parks; (ii) the parks are threatened by many invasive plants arriving from the surrounding urban landscapes; and (iii) many parks are refugia for threatened native species and vegetation. We found 242 alien taxa spreading from ornamental plantings in the parks, seven of them were cultivars of native taxa, 21 were new spreading alien taxa for the Czech Republic, and 26 were native taxa that were part of the garden planting out of their natural area. The most abundant species was the native Hedera helix, which often also behaves expansively in its natural habitats. The most abundant alien species were the invasive neophytes, Impatiens parviflora and Robinia pseudoacacia. The most common aliens recorded in the parks comprise naturalized and invasive species, which spread from the planting in almost 70% of cases, while the corresponding figure for casual aliens was only 18%.
Ecological impacts of dominant alien and native plants on vegetation and soil: does origin matter?
Jan Pergl, Michaela Vítková, Martin Hejda, Josef Kutlvašr, Petr Petřík, Jiří Sádlo, Martin Vojík, Anna Lučanová and Petr Pyšek
The Czech Academy of Sciences, Institute of Botany, Průhonice 252 43, Czech Republic
There is an ongoing debate on whether invasive alien species impose a greater threat to biodiversity compared to native species which are spreading in current landscapes heavily transformed by humans. However, a quantitative assessment on whether the impacts of these two groups of contrasting origins differ is missing. We measured the impacts of dominant invasive alien and native expanding plants in the Czech Republic, Central Europe, on plant communities (species composition and diversity) and soil ecosystem (physico-chemical properties and activity of soil biota). Quantifying the difference in impact between the two groups of dominant species makes it possible to express the net impact of invasive aliens.
Here, we present first results from soil analyses in sites dominated by native vs alien species. We studied five native dominants (Calamagrostis epigejos, Filipendula ulmaria, Phalaris arundinacea, Rubus idaeus and Urtica dioica) and five alien dominants (Impatiens glandulifera, Lupinus polyphyllus, Reynoutria sp., Solidago sp. and Telekia speciosa). Seasonal nutrient availability and soil microbial activity were sampled three times during the vegetation season, for four weeks in each sampling period time. For nutrient availability, we used PRS ion exchange probes that measured NO3–-N, NH4+-N, P, K, S, Ca, Mg, Mn, Al, Fe, Cu, Zn, B, Pb, and Cd. Microbial activity and soil fauna were analysed by burying bags with pure cellulose paper and three different mesh sizes to account for different size groups of fauna (0.1 mm – permeable to bacteria, fungi and protozoa; 1 mm – permeable to microflora, micro-and meso-arthropods; and 4 mm – freely permeable to soil fauna). The differences among the impacts of dominant native and alien plants will be discussed.
Optimising the long-term management of invasive species affecting biodiversity and the rural economy using adaptive management
Bárbara Langdon1,2, David Burslem3, Paul Caplat4, Thomas Cornulier3, Laura Fasola5, Alessandra Fidelis6, Julio Lancelotti7, Lía Montti8, Martín Nuñez9, Steve Palmer3, Aníbal Pauchard1,2, Euan Phimister3, Priscila Powell10, Ignacio Rodriguez11, Ignacio Roesler12, Justin Travis3, Claudio Verdugo13, Xavier Lambin3 and the CONTAIN Consortium
1Laboratorio de Invasiones Biológicas (LIB), Facultad de Ciencias Forestales, Universidad de Concepción, Chile
2Instituto de Ecología y Biodiversidad (IEB), Chile
3Institute of Biological and Environmental Sciences, University of Aberdeen, Scotland
4School of Biological Sciences, Queen’s University of Belfast, Ireland
5 Dirección Regional Patagonia Norte, Administración Parques Nacionales, Argentina / CONICET/ Aves Argentinas-Asociación Ornitológica del Plata.
6 Departamento de Botânica, Instituto de Biociências (Rio Claro), Universidade Estadual Paulista, Brazil
7 Centro Nacional Patagónico (IPEEC-CENPAT), Argentina / CONICET
8 CONICET-Instituto de Investigaciones Marinas y Costeras, Universidad Nacional de Mar del Plata, Buenos Aires / Instituto de Ecología Regional (IER-CONICET), Argentina
9 Grupo de Ecología de invasiones (INBIOMA-CONICET), Universidad Nacional Del Comahue, Argentina.
10 Instituto de Ecología Regional, Universidad Nacional de Tucumán, Argentina / CONICET
11 Centro de Humedales Rio Cruces (CEHUM), Universidad Austral de Chile, Chile
12 Laboratory of Ecology and Animal Behavior, Faculty of Exact and Natural Sciences, University of Buenos Aires, Argentina / IEGEBA-CONICET/Aves Argentinas-Asociación Ornitológica del Plata
13 Instituto Patología Animal, Facultad de Ciencias Veterinarias, Universidad Austral de Chile, Chile
A large number of highly damaging invasive non-native species (INNS) have become established in South America. They affect native species, ecosystems and livelihoods. Many INNS are now so widespread that eradication is not an option. Their spread must be contained and their density reduced, in the long-term, in those areas where taking no action is not acceptable. This must be done as cost effectively as possible, considering questions as: by how much should INNS density be reduced, What harm would be caused in the future if no action was taken? How should the desired reduction be achieved?, Where should the species be reduced? A further important consideration is that INNS are mobile. They have been able to spread when they first invaded and can re-invade areas from which they have been removed through dispersal.
This project aims to design and introduce to stakeholders a user-friendly decision tool that hopefully will become widely used in Latin America. To make sure that the approach is relevant for different contexts in Latin America, work will be done with example species that have large impacts, and for which data already exist (invasive pines, privet, and mink). Plausible scenarios for data-poor pine species, exotic grasses and carnivorous wasps, which impact local communities in Brazil, Argentina and Chile will also be modeled. The most effective strategic management will be found using sophisticated computer simulations considering species ecology, dispersal and intervention costs in a spatial context. Where new data would most effectively reduce uncertainty on the best course of action will be identified. The problem this project aims to tackle is complex, and it will be embedded in a process of co-operative adaptive management, so that managers continually improve their effectiveness by confronting different models to data. The project will also be used as a way to build research capacity in Latin America, by training early career researchers and PhD students by means of research visits, continuous collaboration and workshops. This project will have a tangible positive and immediate impact on people and biodiversity in Latin America by delivering a step-change in the management of problematic INNS.
The invasive potential of forestry species in South Central Chile: first steps towards management planning
Bárbara Langdon1,2, Aníbal Pauchard1,2 and Ramiro O. Bustamante2,3
1Laboratorio de Invasiones Biológicas (LIB), Facultad de Ciencias Forestales, Universidad de Concepción, Victoria 631, Barrio Universitario, Concepción, Chile
2Instituto de Ecología y Biodiversidad (IEB), Chile
3Laboratorio de Ecología Geográfica, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
Tree invasions are a threat to biodiversity conservation and although it is difficult to predict the future spread of invasive tree species, there are tools available which could allow some estimations. The last report on Chilean Forest Resources, shows that commercial plantations reach 2,447,591 ha, with P. radiata (1,469,718 ha), E. globulus (563,813 ha), Eucalyptus nitens (246,726 ha), Pinus ponderosa (27,775 ha), and Pseudotsuga menziesii (16,222 ha) among the main planted species. The same report indicates that according to annual plantation surface, P. radiata is still the most planted species, followed by Eucalyptus species, located mostly in the South-Central Regions of Chile.
We aimed to (i) assess whether forestry species, such as Eucalyptus globulus, Eucalyptus grandis, Eucalyptus nitens, Pinus contorta, Pinus ponderosa, Pinus radiata and Pseudotsuga menziesii, used with commercial purposes in South-Central Chile, conserve their niche in the new environment, and (ii) estimate the invasion stage of each species. Bioclimatic variables and occurrences at the native and the invaded (i.e. South-central Chile) ranges were used to elucidate whether climatic niche requirements are conserved (or not) in the invaded region, and whether the distribution has allowed a geographical equilibrium in the invaded range. Global and Regional (South-central Chile) Species Distribution Models (SDM) were constructed to discern what fraction of the fundamental niche is expressed in the invaded range. Results showed that the Global SDM has a significantly better fit than the regional or native SDMs. From the seven species assessed, none of them are at equilibrium with the environment, and only two of them, Pinus contorta and Pseudotsuga menziesii, conserve their climatic niche. The same trend is shown in the global-regional comparison. Populations from the studied species, are far from stabilizing, with a high proportion of them establishing outside the predicted areas.
According to our results, these forestry species are in an early stage of the invasion process in Chile, when comparing with the situation registered in other regions. This opens an opportunity to avoid major impacts, which should reduce managing costs. These results are fundamental keys to develop biosecurity tools, which will allow decision makers and managers to prioritize between species and areas to manage invasions, enhancing efficiency of management activities.
Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) thematic assessment of invasive alien species and their control
Aníbal Pauchard1,2, Helen Roy3 and Peter Stoett4
1Laboratorio de Invasiones Biológicas (LIB), Facultad de Ciencias Forestales, Universidad de Concepción, Chile
2Instituto de Ecología y Biodiversidad (IEB), Chile
3Biological Records Centre, NERC Centre for Ecology and Hydrology – Wallingford, Crowmarsh Gifford, Oxfordshire OX10 8BB, United Kingdom
4Faculty of Social Science and Humanities, University of Ontario, Oshawa, ON, Canada
Invasive alien species were highlighted as one of five main direct drivers of global diversity declines within the recently published Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) Global Assessment report on biodiversity and ecosystem services. Recently IPBES announced the scope for a thematic assessment of invasive alien species and their control; this will be the first comprehensive assessment. The assessment will comprise six chapters: 1. Introduction; 2. Analysis and synthesis of past and future trends in the spread, pathways, evolutionary change and distribution of invasive alien species and gaps in existing knowledge; 3. Analysis and synthesis of direct and indirect drivers responsible for the introduction, spread, abundance and dynamics of invasive alien species; 4. Global and overall analysis and synthesis of the environmental, economic and social impact of invasive alien species; 5. Effectiveness of past and current programmes and tools for the global, national and local prevention and management of invasive alien species and their impacts; 6. Future options for the prevention and management of invasive alien species and analysis of possible support tools for decision makers. A number of overarching themes are being developed to guide the assessment including interactions of invasive alien species climate change.
The IPBES assessment of invasive alien species and their control will bring together more than 70 experts spanning diverse disciplines. The completed assessment will be presented to the tenth session of the IPBES Plenary composed of representatives from over 130 member States.
A plea for multiple responses to invasive plant species exemplified by the case of Ailanthus altissima
Department of Ecology, Ecosystem Science/Plant Ecology, Technische Universität Berlin, D-12165 Berlin, Germany
Widespread invasive plant species can negatively affect biodiversity and are thus often subject to legal regulations, prevention and control. Yet, these actions require substantial resources, do not guarantee success, and carry the risk of losing the benefits that may be associated with invasive species. Therefore, I advocate for the increased use of multiple responses to invasive species. These responses should be evidence-based and consider the context dependence of invasion processes, associated risks and benefits, as well as, the underlying societal values, including the aim of biodiversity conservation. The case of Ailanthus altissima (tree of heaven), a widespread invasive tree species in Europe and beyond, exemplifies limitations of a general ban of invasive species since invasion risks and invasion impacts cannot be generalized for natural, rural or urban ecosystems. The case of A. altissima further shows significant advantages to be obtained with multiple responses to widespread invasive species. These findings can be useful in adapting regulations or management plans for A. altissima and other widespread invasive plant species.
Grindelia squarrosa – economically useful or an invasive plant in Europe ?
Myroslav Shevera1, Oksana Kucher1, Liudmyla Zavialova1, Katarzyna Bzdęga2, Teresa Nowak2, Adrian Zarychta2 and Barbara Tokarska-Guzik2
1I.M.G. Kholodny Institite of Botany, National Academy of Sciences of Ukraine, Kyiv, Ukraine 2Department of Botany and Nature Protection, Faculty of Biology and Environmental Protection, University of Silesia in Katowice, Poland
Grindelia squarrosa (Pursh) Dunal is a species of North American origin which was introduced to Europe as a medicinal plant at the beginning of the 19th century. At the turn of the 19th and 20th centuries, it was known from botanical gardens in Montpellier, Berlin or Kew. The first records of the species outside cultivation were reported from Belgium (1920), Lithuania (1946) and Ukraine (1949). From the middle of the 20th century, the species has been recorded in 16 European countries and recently also in Georgia (Fig.1). In some countries, the species has shown rapid spread over a short period of time. In the Ukraine, for example, in the years 1970-1980, the number of records increased from 26 to 53, while during the following 20 years G. squarrosa was recorded in 91 new sites. Current data (published and herbarium materials) document the occurrence of G. squarrosa in 301 localities. Further spread of the species is likely, especially in countries in which it has been recorded in a single or at few localities. Additionally, the traits of the species may further promote its spread. Grindelia squarrosa is one of those plant species that are very well acclimatized to conditions of low precipitation, low nutrient, high elevation and large variations in temperature. It is able to colonise various type of habitats, including arid ones. Due to its healing properties, the plant is grown on plantations (e.g. in Poland). More importantly, the species is considered a promising biofuel, which has characteristics in its properties close to biojet fuel. The plants may therefore potentially be cultivated for biofuel production in semiarid and arid lands. The advantages of using this biologically derived fuel could be substantial. Furthermore, uses of G. squarrosa as a substitute to abietic acid, may also include agrochemical, medicinal, and the naval stores industries. Considering both the biological characteristics of the species and its utility for humans, it is necessary to monitor the spread of the species jointly with the assessment of its impact on native biodiversity.
Advancing understanding of invasion ecology with Pines.
Susan Nuske1, Paul Kardol1, David Wardle2, Marie-Charlotte Nilsson Hegethorn1, Jane Smith3, Aníbal Pauchard4, Alex Fajardo5, Duane Peltzer6, Martin Nuñez7 and Michael Gundale1
1Swedish University of Agricultural Sciences, Department of Forest Ecology and Management, Umeå, Sweden
2Nanyong Technological University, Asian School of the Environment, College of Science, Singapore
3US Forestry Service, Pacific Northwest Research Station, Corvallis, USA
4Universidad de Concepción, Departamento de Manejo de Bosques y Medio Ambiente, Facultad de Ciencias Forestales, Chile
5Centro de Investigación en Ecosistemas de la Patagonia (CIEP), Ecosistemas Terrestres, Chile
6Landcare Research, Lincoln, New Zealand
7National University of Comahue, Centro Regional Universitario Bariloche, Neuquén, Argentina
Pine species have been introduced around the world for timber, soil stabilization and wind breaks. Selection for highly productive species and provenances has led to productive forestry, but also to species that can readily spread and become invasive in otherwise productive pasture land, or biodiverse native grass- or shrub-land. Our research uses Pinus contorta as a model species to investigate the mechanisms that underpin invasion ecology. Our international network of field sites enabled us to compare native ranges (USA and Canada) with the introduced and invaded ranges (New Zealand, Chile and Argentina). In order to disentangle the relative effects of genetics, abiotic nutrients and microbial community on seedling growth, we performed an experiment that combined sterilization treatments, provenances and measurements of soil nutrients and fungal communities of soil and roots while keeping environmental conditions stable in a growth chamber ‘home-versus-away’ design. Our research allows us to compare multiple hypotheses at once, advancing understanding of invasion ecology.
Unravelling context dependency in invasion science
Department of Geography, King’s College London, London, UK
The context of invasion matters: it can determine whether, when and where invaders fail or succeed; which systems are resistant or vulnerable to invasions and when; the impacts that invaders cause and the approaches through which they may be managed. Unravelling this context dependence is a critical challenge in invasion science, and an essential step towards greater generality and predictive ability. Drawing on experimental, observational and theoretical examples from around the world, I will demonstrate how process-based understanding derived from community ecology can help us unpack and understand context dependencies in plant invasions.