Biodiversity - Invasive species

Title

Reference

Forests 2011, 2(2), 486-504; doi:10.3390/f2020486
Part EU-funded

Author(s)

Jan Stenlid, Jonàs Oliva, Johanna B. Boberg and Anna J.M. Hopkins

Study type

Peer Review Journal

Abstract

New diseases in forest ecosystems have been reported at an increasing rate over the last century. Some reasons for this include the increased disturbance by humans to forest ecosystems, changed climatic conditions and intensified international trade. Although many of the contributing factors to the changed disease scenarios are anthropogenic, there has been a reluctance to control them by legislation, other forms of government authority or through public involvement. Some of the primary obstacles relate to problems in communicating biological understanding of concepts to the political sphere of society. Relevant response to new disease scenarios is very often associated with a proper understanding of intraspecific variation in the challenging pathogen. Other factors could be technical, based on a lack of understanding of possible countermeasures. There are also philosophical reasons, such as the view that forests are part of the natural ecosystems and should not be managed for natural disturbances such as disease outbreaks. Finally, some of the reasons are economic or political, such as a belief in free trade or reluctance to acknowledge supranational intervention control. Our possibilities to act in response to new disease threats are critically dependent on the timing of efforts. A common recognition of the nature of the problem and adapting vocabulary that describe relevant biological entities would help to facilitate timely and adequate responses in society to emerging diseases in forests.

Policy theme(s)

Biodiversity >> Threats to biodiversity >> Invasive species
Forests >> Forest protection >> Forest pests and diseases

Keywords

biosecurity; communicating biological concepts; forest health; global change; invasive pathogens; legislation; pathway analysis; species concepts

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jan.stenlid@slu.se

Title

Reference

Journal of Vegetation Science
DOI: 10.1111/j.1654-1103.2011.01340.x

Author(s)

Benjamin S. Ramage, Alison B. Forrestel, Max A. Moritz, Kevin L. O'Hara

Study type

Peer Review Journal

Abstract

Questions
How is sudden oak death disease progression affected by forest type? Which specific factors influence mortality rates and patterns? How do these trends vary across spatial scales?
Location
Point Reyes National Seashore, California, USA.
Methods
Sudden oak death, caused by the exotic pathogen Phytophthora ramorum, is affecting forests throughout coastal California. We investigated disease progression in tanoak (Notholithocarpus densiflorus syn. Lithocarpus densiflorus), the most susceptible species, in two distinct forest types: coast redwood (Sequoia sempervirens) and Douglas-fir (Pseudotsuga menziesii var. menziesii). Within each forest type, we used a variant of a split-plot design to sample proximate areas at two different stages of disease progression (relatively unaffected vs severely impacted), and used generalized linear mixed effects models to analyse these data.
Results
Annual mortality rates were much higher in Douglas-fir (10.1–26.2%) than in redwood (3.2–8.2%) forest, and data suggested that similarly divergent rates will continue into the future (proportions of surviving trees with disease symptoms remained constant from the beginning to the end of the study period). Across both forest types, survival probabilities were lower for tanoaks with larger diameters and tanoaks in plots (1/20 ha) and neighbourhoods (3-m radius) with greater basal area of previously killed tanoak. All variables were significant when included in the same model, suggesting that disease spread is occurring simultaneously at two local spatial scales. Several other biotic and abiotic variables were unrelated to tanoak survival probability.
Conclusions
We detected mortality rates that exceed any rates previously associated with sudden oak death, while demonstrating that these rates can vary substantially between adjacent forest types. However, because the Douglas-fir forests of our study area are adjacent to the ocean, which is somewhat uncommon for this forest type, our findings do not necessarily indicate that all Douglas-fir forests with a substantial tanoak component are at risk of similar impacts. Our data also suggest that, in both forest types, local patchiness in disease presence/severity is an ephemeral condition resulting primarily from stochastic processes (e.g. long-distance dispersal events), while intra-plot spread around infected trees is deterministic and probably inevitable. Our findings should inform scientists and managers throughout the world attempting to understand disease progression in regions recently invaded by P. ramorum (e.g. Europe) and/or affected by other exotic forest pathogens.

Policy theme(s)

Biodiversity >> Threats to biodiversity >> Invasive species
Forests >> Forest protection >> Forest pests and diseases

Keywords

Disease ecology; Douglas-fir; Exotic pathogen; Forest disease; Lithocarpus densiflorus; Mortality rate; Notholithocarpus densiflorus; Phytophthora ramorum;
Pseudotsuga menziesii; Redwood; Sequoia sempervirens; Tanoak

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http://onlinelibrary.wiley.com/doi/10.1111/j.1654-1103.2011.01340.x/full
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bsramage@berkeley.edu

Title

Reference

Ecology Letters
Volume 14, Issue 11, pages 1108–1116, November 2011

Author(s)

Sarah E. Haas, Mevin B. Hooten, David M. Rizzo, Ross K. Meentemeyer

Study type

Peer Review Journal

Abstract

Empirical evidence suggests that biodiversity loss can increase disease transmission, yet our understanding of the 'diversity-disease hypothesis' for generalist pathogens in natural ecosystems is limited. We used a landscape epidemiological approach to examine two scenarios regarding diversity effects on the emerging plant pathogen Phytophthora ramorum across a broad, heterogeneous ecoregion: (1) an amplification effect exists where disease risk is greater in areas with higher plant diversity due to the pathogen's wide host range, or (2) a dilution effect where risk is reduced with increasing diversity due to lower competency of alternative hosts. We found evidence for pathogen dilution, whereby disease risk was lower in sites with higher species diversity, after accounting for potentially confounding effects of host density and landscape heterogeneity. Our results suggest that although nearly all plants in the ecosystem are hosts, alternative hosts may dilute disease transmission by competent hosts, thereby buffering forest health from infectious disease.

Policy theme(s)

Biodiversity >> Threats to biodiversity >> Invasive species
Forests >> Forest protection >> Forest pests and diseases

Keywords

Bayesian hierarchical model; emerging infectious disease; forest ecosystem; landscape epidemiology; Phytophthora ramorum; spatial autocorrelation; species diversity; sudden oak death; zero-inflation

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http://onlinelibrary.wiley.com/doi/10.1111/j.1461-0248.2011.01679.x/abstract
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shaas1@uncc.edu

Title

Benefits and risks of exotic biological control agents

Reference

Volume 56, Number 4, 681-698, DOI: 10.1007/s10526-011-9372-8

Author(s)

Patrick De Clercq, Peter G. Mason and Dirk Babendreier

Study type

Peer Review Journal

Abstract

The use of exotic (=alien) arthropods in classical and augmentative biological control programs has yielded huge economic and ecological benefits. Exotic species of arthropods have contributed to the suppression of key pests in agriculture and forestry or have aided in restoring natural systems affected by adventive species. However, adverse non-target effects of exotic biological control agents have been observed in a number of projects. Non-target effects range from very small effects, e.g. 2% parasitization on a non-target insect on a local level, to massive effects on a large scale. Until now, no consensus on how to judge the magnitude of non-target effects and whether these effects can be tolerated or are unacceptable has emerged. In this paper, we briefly review both the benefits of biological control as well as the associated risks including to human and animal health, plant health and particularly the environment. We also make an attempt at identifying the major challenges for assessing risks and for balancing benefits and risks. There is general agreement that sound risk assessment procedures should precede the release of exotic invertebrate biological control agents and a recent shift-especially for arthropod biological control-from introductions done without meaningful risk assessment studies to projects conducting thorough host range testing can be observed. However, overly stringent regulations that would preclude promising agents from being developed must be avoided.

Policy theme(s)

Agriculture >> Agricultural management >> Crop management
Biodiversity >> Threats to biodiversity >> Invasive species

Keywords

Augmentative biological control ;Augmentation;Classical biological control;Exotic species;Non-target effects;Risk assessment;Risk-benefit analysis

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http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2338.1997.tb00611.x/abstract
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Joop.vanLenteren@medew.ento.wau.nl

Title

Predicting the invasion risk by the alien bee-hawking Yellow-legged hornet Vespa velutina nigrithorax across Europe and other continents with niche models

Reference

Biological Conservation
Volume 144, Issue 9, September 2011, Pages 2142-2150

Author(s)

Claire Villemant , Morgane Barbet-Massin, Quentin Rome

Study type

Peer Review Journal

Abstract

Vespa velutina nigrithorax, an Asian bee-hawking hornet, has been unintentionally introduced in south-western France before 2004 and is currently widely spreading across the country. Its arrival in northern Spain was reported in 2010. The potential invasion risk of the species is assessed using climatic suitability models. We used eight different modelling techniques within an ensemble forecast framework to show that the invasion success in south-western France could have been predicted using data from the native Asian range of the species, while we further used data from both the native and invaded ranges (including a recently established population in Korea) to better predict its potential invasion range across all continents. Results are discussed in terms of the interest of ecological niche modelling for invasion biology, realised niche of the invasive wasp, potential threats to native entomofauna and economic impacts of this new predator. A particular attention is paid to beekeeping activities that are nowadays already threatened by a wide panel of adversary factors.

Policy theme(s)

Biodiversity >> Threats to biodiversity >> Invasive species

Keywords

Beekeeping; Invasive species; Native range; Niche modelling; Vespidae; Social Hymenoptera

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http://www.sciencedirect.com/science/article/pii/S0006320711001315
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villeman@mnhn.fr

Title

Diversity, Loss, and Gain of Malaria Parasites in a Globally Invasive Bird

Reference

PLoS ONE 6(7): e21905. doi:10.1371/journal.pone.0021905

Author(s)

Alfonso Marzal , Robert E. Ricklefs, Gediminas Valkiūnas, Tamer Albayrak, Elena Arriero, Camille Bonneaud, Gábor A. Czirják, John Ewen, Olof Hellgren, Dita Hořáková, Tatjana A. Iezhova, Henrik Jensen, Asta Križanauskienė, Marcos R. Lima , Florentino de Lope, Eyofinn Magnussen, Lynn B. Martin, Anders P. Møller , Vaidas Palinauskas, Péter L. Pap, Javier Pérez-Tris, Ravinder N. M. Sehgal, Manuel Soler, Eszter Szöllősi, Helena Westerdahl, Pavel Zetindjiev, Staffan Bensch

Study type

Peer Review Journal   

Abstract

Invasive species can displace natives, and thus identifying the traits that make aliens successful is crucial for predicting and preventing biodiversity loss. Pathogens may play an important role in the invasive process, facilitating colonization of their hosts in new continents and islands. According to the Novel Weapon Hypothesis, colonizers may out-compete local native species by bringing with them novel pathogens to which native species are not adapted. In contrast, the Enemy Release Hypothesis suggests that flourishing colonizers are successful because they have left their pathogens behind. To assess the role of avian malaria and related haemosporidian parasites in the global spread of a common invasive bird, we examined the prevalence and genetic diversity of haemosporidian parasites (order Haemosporida, genera Plasmodium and Haemoproteus) infecting house sparrows (Passer domesticus). We sampled house sparrows (N = 1820) from 58 locations on 6 continents. All the samples were tested using PCR-based methods; blood films from the PCR-positive birds were examined microscopically to identify parasite species. The results show that haemosporidian parasites in the house sparrows' native range are replaced by species from local host-generalist parasite fauna in the alien environments of North and South America. Furthermore, sparrows in colonized regions displayed a lower diversity and prevalence of parasite infections. Because the house sparrow lost its native parasites when colonizing the American continents, the release from these natural enemies may have facilitated its invasion in the last two centuries. Our findings therefore reject the Novel Weapon Hypothesis and are concordant with the Enemy Release Hypothesis

Policy theme(s)

Biodiversity >> Threats to biodiversity >> Invasive species

Keywords

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http://www.plosone.org/article/info:doi/10.1371/journal.pone.0021905
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Staffan.Bensch@zooekol.lu.se

Title

Climatic Factors Driving Invasion of the Tiger Mosquito (Aedes albopictus) into New Areas of Trentino, Northern Italy

Reference

PLoS ONE 6(4): e14800. doi:10.1371/journal.pone.0014800

Author(s)

David Roiz, Markus Neteler, Cristina Castellani, Daniele Arnoldi, Annapaola Rizzoli

Study type

Peer Review Journal

Abstract

Background
The tiger mosquito (Aedes albopictus), vector of several emerging diseases, is expanding into more northerly latitudes as well as into higher altitudes in northern Italy. Changes in the pattern of distribution of the tiger mosquito may affect the potential spread of infectious diseases transmitted by this species in Europe. Therefore, predicting suitable areas of future establishment and spread is essential for planning early prevention and control strategies.
Methodology/Principal Findings
To identify the areas currently most suitable for the occurrence of the tiger mosquito in the Province of Trento, we combined field entomological observations with analyses of satellite temperature data (MODIS Land Surface Temperature: LST) and human population data. We determine threshold conditions for the survival of overwintering eggs and for adult survival using both January mean temperatures and annual mean temperatures. We show that the 0°C LST threshold for January mean temperatures and the 11°C threshold for annual mean temperatures provide the best predictors for identifying the areas that could potentially support populations of this mosquito. In fact, human population density and distance to human settlements appear to be less important variables affecting mosquito distribution in this area. Finally, we evaluated the future establishment and spread of this species in relation to predicted climate warming by considering the A2 scenario for 2050 statistically downscaled at regional level in which winter and annual temperatures increase by 1.5 and 1°C, respectively.
Conclusions/Significance
MODIS satellite LST data are useful for accurately predicting potential areas of tiger mosquito distribution and for revealing the range limits of this species in mountainous areas, predictions which could be extended to an European scale. We show that the observed trend of increasing temperatures due to climate change could facilitate further invasion of Ae. albopictus into new areas.

Policy theme(s)

Biodiversity >> Threats to biodiversity >> Invasive species
Climate change and energy >> Climate change adaptation >> Biodiversity impacts

Keywords

N/A

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davidroiz@gmail.com

Title

Abundance of introduced species at home predicts abundance away in herbaceous communities.

Reference

Ecology Letters, 2011; 14 (3): 274 DOI: 10.1111/j.1461-0248.2010.01584.x

Author(s)

Jennifer Firn, Joslin L. Moore, Andrew S. MacDougall et al.

Study type

Peer Review Journal

Abstract

Many ecosystems worldwide are dominated by introduced plant species, leading to loss of biodiversity and ecosystem function. A common but rarely tested assumption is that these plants are more abundant in introduced vs. native communities, because ecological or evolutionary-based shifts in populations underlie invasion success. Here, data for 26 herbaceous species at 39 sites, within eight countries, revealed that species abundances were similar at native (home) and introduced (away) sites - grass species were generally abundant home and away, while forbs were low in abundance, but more abundant at home. Sites with six or more of these species had similar community abundance hierarchies, suggesting that suites of introduced species are assembling similarly on different continents. Overall, we found that substantial changes to populations are not necessarily a pre-condition for invasion success and that increases in species abundance are unusual. Instead, abundance at home predicts abundance away, a potentially useful additional criterion for biosecurity programmes

Policy theme(s)

Biodiversity>>Threats to biodiversity >> Invasive species

Keywords

Biogeography; biosecurity; disturbance; global meta-study; homogenization of communities; invasion paradox; mechanisms of invasion; Nutrient Network; plant invasion; propagule pressure

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http://onlinelibrary.wiley.com/doi/10.1111/j.1461-0248.2010.01584.x/abstract
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jennifer.firn@qut.edu.au

Title

Universal criteria for species conservation priorities? Findings from a survey of public views across Europe The New Conservation Debate: Beyond Parks vs. People

Reference

Biological Conservation
Volume 144, Issue 3, March 2011, Pages 998-1007

Author(s)

Anke Fischer, Birgit Bednar-Friedl, Fransje Langers, Marta Dobrovodská, Nicoleta Geamana, Ketil Skogen and Myriam Dumortier

Study type

Peer Review Journal

Abstract

Decisions on biodiversity management and conservation are increasingly based on indicators. These imply, explicitly or implicitly, a number of criteria such as nativeness, rarity, endangeredness and (economic) value. We investigated to which degree such criteria matter to members of the general public and conducted a survey in eight sites across Europe (n = 2378). We explored the relationships between perceived desirability of a species' population increase and six species-related attributes, including previous population change, rarity, vulnerability, harmfulness, value, attractiveness, and nativeness.
For all three species types investigated, previous population change, followed by perceived harmfulness and value, had the strongest relationship with desirability of future increase. Perceived nativeness played only a minor role in informing a species' desirability. A strong relationship between previous change and desirability of future increase could also be found in a number of additional species and six different habitat types, suggesting that previous change is a key criterion that the general public draws on to inform their attitudes towards biodiversity management.
We compare the roles of such criteria for the general public to those used in the scientific and political discourse, and draw conclusions for the use of indicators in the conservation debate, arguing that biodiversity management that is strongly focused on nativeness might fall short of the interests of the citizenship, whereas other criteria, such as population trends, harmfulness and role and value of a species in the ecosystem strongly resonate with the views of the general public.

Policy theme(s)

Biodiversity>>Threats to biodiversity>>Invasive species
Environmental information services>>Environmental communication>>Stakeholder/public engagement

Keywords

Attitudes, Biodiversity, Conservation criteria, Species, Non-native, Invasive

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http://www.sciencedirect.com/science/article/pii/S0006320710004994
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a.fischer@macaulay.ac.uk

Title

Alien Marine Fishes Deplete Algal Biomass in the Eastern Mediterranean

Reference

PLoS ONE 6(2): e17356.
doi:10.1371/journal.pone.0017356

Author(s)

Enric Sala , Zafer Kizilkaya, Derya Yildirim, Enric Ballesteros

Study type

Peer Review Journal

Abstract

One of the most degraded states of the Mediterranean rocky infralittoral ecosystem is a barren composed solely of bare rock and patches of crustose coralline algae. Barrens are typically created by the grazing action of large sea urchin populations. In 2008 we observed extensive areas almost devoid of erect algae, where sea urchins were rare, on the Mediterranean coast of Turkey. To determine the origin of those urchin-less ‘barrens’, we conducted a fish exclusion experiment. We found that, in the absence of fish grazing, a well-developed algal assemblage grew within three months. Underwater fish censuses and observations suggest that two alien herbivorous fish from the Red Sea (Siganus luridus and S. rivulatus) are responsible for the creation and maintenance of these benthic communities with extremely low biomass. The shift from well-developed native algal assemblages to ‘barrens’ implies a dramatic decline in biogenic habitat complexity, biodiversity and biomass. A targeted Siganus fishery could help restore the macroalgal beds of the rocky infralittoral on the Turkish coast.

Policy theme(s)

Biodiversity>>Threats to biodiversity>>Invasive species
Marine ecosystems>>Biodiversity

Keywords

N/A

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esala@ngs.org

Title

Socioeconomic legacy yields an invasion debt

Reference

PNAS January 4, 2011 vol. 108 no. 1 203-207

Author(s)

Franz Essl et al

Study type

Peer Review Journal

Abstract

Globalization and economic growth are widely recognized as important drivers of biological invasions. Consequently, there is an increasing need for governments to address the role of international trade in their strategies to prevent species introductions. However, many of the most problematic alien species are not recent arrivals but were introduced several decades ago. Hence, current patterns of alien-species richness may better reflect historical rather than contemporary human activities, a phenomenon which might be called 'invasion debt'. Here, we show that across 10 taxonomic groups (vascular plants, bryophytes, fungi, birds, mammals, reptiles, amphibians, fish, terrestrial insects, and aquatic invertebrates) in 28 European countries, current numbers of alien species established in the wild are indeed more closely related to indicators of socioeconomic activity from the year 1900 than to those from 2000, although the majority of species introductions occurred during the second half of the 20th century. The strength of the historical signal varies among taxonomic groups, with those possessing good capabilities for dispersal (birds, insects) more strongly associated with recent socioeconomic drivers. Nevertheless, our results suggest a considerable historical legacy for the majority of the taxa analyzed. The consequences of the current high levels of socioeconomic activity on the extent of biological invasions will thus probably not be completely realized until several decades into the future.

Policy theme(s)

Biodiversity >> Threats to biodiversity >> Invasive species

Keywords

exotic plants and animals, species establishment, time lag

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http://www.pnas.org/content/108/1/203.short
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stefan.dullinger@univie.ac.at

Title

Turning back the tide of American mink invasion at an unprecedented scale through community participation and adaptive management

Reference

Biological Conservation
doi:10.1016/j.biocon.2010.10.013

Author(s)

Rosalind Bryce, Matthew K. Oliver, Llinos Davies, Helen Gray, Jamie Urquhart and Xavier Lambin

Study type

Peer Review Journal

Abstract

Successful eradications of harmful invasive species have been mostly confined to islands while control programs in mainland areas remain small, uncoordinated and vulnerable to recolonisation. To allow the recovery of threatened native species, innovative management strategies are required to remove invasives from large areas. We took an adaptive approach to achieve large scale eradication of invasive American mink in North East Scotland. The project was centred on the Cairngorms National Park (Scotland), with the primary aim of protecting endangered water vole populations. The project was initiated by scientists and supported and implemented through a partnership comprising a government agency, national park authority and local fisheries boards. Capitalising on the convergent interests of a diverse range of local stakeholders, we created a coordinated coalition of trained volunteers to detect and trap mink. Starting in montane headwaters, we systematically moved down river catchments, deploying mink rafts, an effective detection and trapping platform. Volunteers took increasing responsibility for raft monitoring and mink trapping as the project progressed. Within 3 years, the project removed 376 mink from 10570 km2 with the involvement of 186 volunteers. Capture rate within sub-catchments increased with greater connectivity to mink in other sub-catchments and with proximity to the coast where there is more productive habitat. The main factor underpinning the success of this project was functional volunteer participation. The project is a reason for optimism that the tide of invasion can be rolled back on a large scale where the convergent interest of local communities can be harnessed.

Policy theme(s)

Biodiversity >> Threats to biodiversity >> Invasive species
Environmental information services >> Environmental communication >> Stakeholder/public engagement

Keywords

American mink, Invasive alien species, Eradication, Volunteer participation,
Adaptive management, Community conservation

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http://www.sciencedirect.com/science/article/pii/S0006320710004568
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X.lambin@abdn.ac.uk