Invasive Species

The growing pace of international commerce has created an increased risk of invasion by alien species, which often take root and thrive in their new environment, often at great costs for the local biota and economy. The risk of introduction of harmful organisms into the United States is increasing exponentially, with costs to the American economy measured in hundreds of billions of dollars. This report offers recommendations to improve biosecurity measures at US ports, as well as a possible funding mechanism based upon the polluter-pays principle.

Over the last century, large-scale water development of the upper Rio Grande in the U.S. and Mexico, and of the Rio Conchos in Mexico, has resulted in progressive channel narrowing of the lower Rio Grande in the Big Bend region. We used methods operating at multiple spatial and temporal scales to analyze the rate, magnitude, and processes responsible for channel narrowing. These methods included: hydrologic analysis of historic stream gage data, analysis of notes of measured discharges, historic oblique and aerial photograph analysis, and stratigraphic and dendrogeomorphic analysis of inset floodplain deposits. Our analyses indicate that frequent large floods between 1900 and the mid-1940s acted as a negative feedback mechanism and maintained a wide, sandy, multi-threaded river. Declines in mean and peak flow in the mid-1940s resulted in progressive channel narrowing. Channel narrowing has been temporarily interrupted by occasional large floods that widened the channel, however, channel narrowing has always resumed. After large floods in 1990 and 1991, the active channel width of the lower Rio Grande has narrowed by 36-52%. Narrowing has occurred by the vertical accretion of fine-grained deposits on top of sand and gravel bars, inset within natural levees. Channel narrowing by vertical accretion occurred simultaneously with a rapid invasion of non-native riparian vegetation (Tamarix spp., Arundo donax) which created a positive feedback and exacerbated the processes of channel narrowing and vertical accretion. In two floodplain trenches, we measured 2.75 and 3.5 m of vertical accretion between 1993 and 2008. In some localities, nearly 90% of bare, active channel bars were converted to vegetated floodplain during the same period. Upward shifts of stage-discharge relations occurred resulting in over-bank flooding at lower discharges, and continued vertical accretion despite a progressive reduction in stream flow. Thus, although the magnitude of the average annual flood was reduced between 40 and 50%, over-bank flooding continued. These changes reflect a shift in the geomorphic nature of the Rio Grande from a wide, laterally unstable, multi-thread river, to a laterally stable, single-thread channel with cohesive, vertical banks, and few active in-channel bars.

Ecologists are searching for models, frameworks, and principles that provide a bridge between theory and the practice of restoration. Successional management has been proposed as a useful model for managing and restoring invasive-plant-dominated rangeland because it provides a framework in which ecological processes can be manipulated by managers to achieve a desired plant community. Successional management identifies three general causes of succession (site availability [disturbance], species availability [colonization], and species performance) and suggests that managers address the ecological process influencing each general cause in a coordinated fashion to direct plant community dynamics. We tested successional management using various techniques to restore invasive-weed-dominated rangeland. Our hypothesis was that successively modifying the factors influencing the causes of succession in an integrated fashion would favor the establishment and abundance of native grasses over singularly applied treatments. Thus, we anticipated that the majority of responses to multiple treatments would be explained by higher order interactions, especially in the final year of the study . To test this hypothesis, we used a model system within a Festuca campestris/Pseudoroegneria spicata habitat among pothole wetlands dominated by Centaurea maculosa and Potentilla recta, two invasive species. We used three herbicide treatments (none, 2,4-D, and picloram) to influence species performance; two seeding methods (imprinting, i.e., creating a small depression and broadcasting, and no-till drilling) to influence disturbance; three seeding rates (977, 1322, and 1557 seeds/m 2 ) to influence colonization; and two cover crop treatments (with and without Triticum aestivum) to influence soil N and favor native grasses. Treatments were factorially arranged and replicated four times in a randomized complete block design in 2001 and sampled in 2002 and 2004. As predicted, plant response to treatments was dominated by two-and three-way interactions in 2004. The highest seeding rate (colonization) combined with no-till drilling (disturbance) produced the highest native grass density in 2002. These effects persisted into 2004 for P. spicata, but not for F. campestris or F. idahoensis. Combining picloram with no-till drill seeding also produced a high density of P. spicata. Drill seeding at 977 seeds/m 2 favored F. idahoensis density, while no-till drilling at 1322 seeds/m 2 favored its biomass in 2004. F. idahoensis established well after drill seeding with a cover crop and applying 2,4-D. Herbicides reduced native forb density and/or biomass, with early season forbs being more sensitive to picloram and summer forbs being more sensitive to 2,4-D. Herbicides increased exotic grasses' density and biomass but had no effect on native grasses. In most cases, integrating treatments that addressed multiple causes of succession favored a desired plant community. Thus, we accomplished our goal of using successional management to direct plant communities toward native desired species, but the treatments used did not improve species richness. Since naturally occurring native forbs did not respond favorably to any treatment combination, ecological restoration using successional management may best be thought of as an iterative procedure where various components and processes of the system are methodically repaired or replaced over time.

One of the primary tools for raising awareness on biological invasions has been the publication of species accounts of the most prominent alien invaders. Until now such compilations have been available only for particular taxa, biomes and/or regions (Cronk and Fuller 2001; Weber 2003; Weidema 2000). In Europe, species accounts for selected invasive species have been published for a few countries or

Different international plant protection organisations advocate different schemes for conducting pest risk assessments. Most of these schemes use structured questionnaire in which experts are asked to score several items using an ordinal scale. The scores are then combined using a range of procedures, such as simple arithmetic mean, weighted averages, multiplication of scores, and cumulative sums. The most useful schemes will correctly identify harmful pests and identify ones that are not. As the quality of a pest risk assessment can depend on the characteristics of the scoring system used by the risk assessors (i.e., on the number of points of the scale and on the method used for combining the component scores), it is important to assess and compare the performance of different scoring systems. In this article, we proposed a new method for assessing scoring systems. Its principle is to simulate virtual data using a stochastic model and, then, to estimate sensitivity and specificity values from these data for different scoring systems. The interest of our approach was illustrated in a case study where several scoring systems were compared. Data for this analysis were generated using a probabilistic model describing the pest introduction process. The generated data were then used to simulate the outcome of scoring systems and to assess the accuracy of the decisions about positive and negative introduction. The results showed that ordinal scales with at most 5 or 6 points were sufficient and that the multiplication-based scoring systems performed better than their sum-based counterparts. The proposed method could be used in the future to assess a great diversity of scoring systems.

Here in Hawaii, the only ones in the rat race are mongooses, along with Federal and State officials wanting to kill both rats and mongooses.  However, there is a big flaw in the recent Federal and State proposal for statewide eradication of Hawaii's rodents and mongooses, currently under review.  Here is the argument against eradication.

Temporal trends in attributes of restored ecosystems have been described conceptually as restoration trajectories. Measures describing the maturity or ecological integrity of a restoration site are often assumed to follow monotonically increasing trajectories over time and to eventually reach an asymptote representative of a reference ecosystem. This assumption of simple, predictable restoration trajectories underpins federal and state policies in the United States that mandate wetland restoration as compensation for wetlands damaged during development. We evaluated the validity of this assumption by tracking changes in 11 indicators of floristic integrity, often used to determine legal compliance, in 29 mitigation wetlands. Each indicator was expressed as a percentile relative to the distribution of that indicator among .100 naturally occurring reference wetlands. Nonlinear regression was used to fit two alternative restoration trajectories to data from each site: an asymptotic (negative exponential) increase in the indicator over time and a peaked (double exponential) relationship. Depending on the particular indicator, between 48% and 76% of sites displayed trends that were at least moderately well described (R 2 . 0.5) by one of the two models. Floristic indicators based on species richness, including native richness, number of native genera, and the floristic quality index, rapidly increased to asymptotes exceeding levels in a majority of reference wetlands. In contrast, indicators based on species composition, including mean coefficient of conservatism and relative importance of perennial species, increased very slowly. Thus, some indicators of restoration progress followed increasing trajectories and achieved or surpassed levels equivalent to high-quality reference sites within five years, whereas others appeared destined to either not reach equivalency or to take much longer than mitigation wetlands are typically monitored. Finally, some indicators of restoration progress, such as relative importance of native species, often increased over the first five to 10 years and then declined, which would result in a misleading assessment of progress if based on typical time scales of monitoring. Therefore, the assumption of simple, rapid, and predictable restoration trajectories that underlies wetland mitigation policy is unrealistic.

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The economics of invasive species control and management: The complex road ahead As the world's economies continually grow more interconnected, an increasing number of species are being introduced into areas to which they are not native. Some of these non-native or alien species are considered invasive, with Executive Order 13112 defining an invasive species as ''an alien species whose introduction does or is likely to cause economic or environmental harm or harm to human health'' (ISAC, 2006; NISC, 2008). The Invasive Species Advisory Committee (ISAC) suggests expanding this definition to include species that adversely affect animal or plant health, and to clarify what is meant by causing harm. Specifically, an alien species would be considered invasive if it generates ecological and economic damages that exceed any offsetting benefits, such that the net impact is negative (ISAC, 2006). Only a small proportion of introduced non-native species-perhaps one out of every thousand, based on the 10-10-10 rule (Williamson, 1996)-are considered invasive by traditional definitions. But the associated damages can be so severe that invasive alien species (IAS) have become a real concern. IAS are believed to be the one of the most important causes of biodiversity loss worldwide (MEA, 2005; Holmes, 1998), as invaders may prey upon native species or outcompete native species for habitat and resources (ISAC, 2006). For instance, mute swans have displaced many native waterfowl in North America, feral goats in Maui have purged native Hawaiian plants that were maladapted for grazing, and lake trout are outcompeting native cutthroat trout in Yellowstone Lake (ISAC, 2006). Examples of pathogens spread from livestock to threatened wildlife include the Rinderpest virus which has spread from Zebu cattle to Serengeti wildebeest and cape buffalos (McCallum and Dobson, 1995; Plowright, 1982), the tapeworm Cysticercus tenuicollis which infects Andean deer in Chile, and several viruses (rabies, canine parvovirus, canine adenovirus, and canine distemper virus) which spread from domestic dogs to the endangered Ethiopian wolf (Laurenson et al., 1988). Additionally, IAS can spread diseases to people, livestock, and cultivated plants. West nile virus and avian influenza are examples of invasive pathogens spread to humans by wildlife. Avian influenza is also spread to domestic poultry from wild birds (Shim and Galvani, 2009). Some other pathogens that are spread from wildlife to domestic livestock include bovine tuberculosis, which is spread from white-tailed deer to cattle in Michigan (Schmitt et al., 1997), and brucellosis, which is spread from elk to cattle in Wyoming (Dobson and Meagher, 1996). IAS can also directly damage agricultural crops and nursery stocks. Soybean aphids, for example, have caused significant damage to soybean crops (Zhang et al., 2010), and emerald ash borer has destroyed millions of dollars of ash trees in nurseries, residential communities, and in the wild (Sydnor et al., 2007). Rangelands are also threatened by a variety of invasive species such as yellow starthistle (Centaurea solstitialis) in California (Eiswerth and van Kooten, 2002).

PL: Wieloletnia presja antropogeniczna wywarła głębokie zmiany w krajobrazie doliny Kłodnicy w Gliwicach. W artykule przedstawiono różne warianty rewitalizacji doliny rzeki Kłodnicy, możliwe do realizacji w ramach funduszy unijnych, krajowych, partnerstwa publiczno-prywatnego i budżetu obywatelskiego. Zdecydowana większość mieszkańców (81%) źle ocenia stan badanego odcinka doliny, wskazując na potrzebę jej rewitalizacji (76%). Zaproponowane w pracy rozwiązania, zgodne z koncepcją zielonej architektury, pozwoliłyby na odtworzenie potencjału ekohydrologicznego doliny Kłodnicy i stworzenie przyjaznej dla mieszkańców przestrzeni publicznej. Przywrócenie właściwego stanu ekosystemów rzeki umożliwiłoby uzyskanie wielu usług ekosystemowych (poprawa bezpieczeństwa powodziowego, poprawa warunków aerosanitarnych, estetyzacja krajobrazu), podnoszących jakość i standard życia mieszkańców. Przewidziane w projekcie obiekty i infrastruktura stanowiłyby interesującą ofertę spędzania czasu wolnego oraz służyłyby podniesieniu świadomości ekologicznej mieszkańców. EN: Long-term anthropopressure caused negative changes in the landscape of the Kłodnica valley in Gliwice. The article presents various variants of revitalization of the Kłodnica valley. They are possible to realize within European funds, national funds, public-private partnership and the civil budget. Most inhabitants (81%) poorly assessed the state of the studied section of the Kłodnica valley. The inhabitants pointed also at the need to the revitalization of the valley (76%). Solutions proposed in the article, according to green architecture concept, would allow the reconstruction of the ecohydrological potential of the Kłodnica valley and creating friendly public space. The restoration of the proper state of river ecosystems would allow many valuable ecosystem services (improving flood safety, micro-climate regulation, aesthetization of landscape), which increases the standard and quality of life of inhabitants. Objects and infrastructure proposed in the project would be an interesting offer for spending leisure time and would increase the ecological awareness of inhabitants.

We investigated the seasonal occurrence of Hemimysis anomala in the diets of fish that prey on macroinvertebrates at two sites with established Hemimysis populations east of Oswego, NY, during 2009-2010. In 2009, we examined 320 stomachs from 10 species and found Hemimysis only in alewife (Alosa pseudoharengus), rockbass (Ambloplites rupestris), and yellow perch (Perca flavescens). Of those species, alewife consumed Hemimysis most frequently and it represented a greater proportion of their diets. During 2009, the dry weight composition of Hemimysis in alewife diets varied seasonally between b 1% in June, 5% in July, 98.5% in August, and 18.8% in September. In contrast, we examined 667 stomachs from 15 species in 2010 and observed Hemimysis in only one alewife and two rockbass stomachs. For alewife from September 2009, we found no relationship between predator size and the number of Hemimysis consumed, or between the presence of Hemimysis in fish diets and the presence of other diet taxa or diet diversity. Fish diets collected as bycatch from other assessments revealed large numbers of Hemimysis in fishes that had not previously been observed consuming Hemimysis in Lake Ontario, including cisco (Coregonus artedi) and white perch (Morone americana).

Using a bio-economic model of zebra mussels (Dreissena polymorpha), we examine the expected economic value of prevention, control and eradication alternatives for the freshwater mussel in Lake Okeechobee (Florida, USA). We include two emerging technologies for zebra mussel (ZM) control: (1) a natural pesticide called Zequanox, and (2) hot wash stations at boat ramps. We employ water management district data, user data collected via a phone survey, and mitigation expenditures from infested locations elsewhere to estimate the potential damage from the introduction of zebra mussels in Florida. Methods used include static cost transfer estimation, econometric cost estimation, and stochastic-dynamic simulation. We use our bio-economic model to compare costs and risks with and without the emerging technologies. We also consider the impact of technology adoption rates by anglers, management policy efficacy, and opportunity costs associated with ZM control. Results indicate that, without investment in prevention, there is a very high probability that Florida waterways will be infested with zebra mussels by year 2025, and expected environmental damages and management costs are high. Slow response due to poor detection methods or insufficient control efforts will lead to a moderate probability of a significant infestation. Rapid reaction and enhanced prevention efforts are expected to greatly reduce the probability of ZM infesting Lake Okeechobee by 2025, and to generate much higher expected net benefits.

There is an increasing need and interest in including indicators of landscape fragmentation in monitoring systems of sustainable landscape management. Landscape fragmentation due to transportation infrastructure and urban development threatens human and environmental well-being by noise and pollution from traffic, reducing the size and viability of wildlife populations, facilitating the spread of invasive species, and impairing the scenic and recreational qualities of the landscape. This paper provides the rationale, method, and data for including landscape fragmentation in monitoring systems, using as an example the Swiss Monitoring System of Sustainable Development (Monet). We defined and compared four levels of fragmentation analysis, or fragmentation geometries (FGs), each based on different fragmenting elements, e.g., only anthropogenic, or combinations of anthropogenic and natural elements. As each FG has specific strengths and weaknesses, the most appropriate choice of FG depends on the context and objectives of a study. We present data on the current degree of landscape fragmentation for the five ecoregions and 26 cantons in Switzerland for all four FGs. Our results show that the degree of landscape fragmentation as quantified by the effective mesh size method is strongly supported by the postulates and indicator selection criteria of Monet, and we identify the most suitable FG focusing on the land area below 2,100 m (e.g., excluding lakes) and allowing for an equitable comparison of fragmentation degrees among regions that differ in area covered by lakes and high mountains. For a more detailed analysis of landscape fragmentation in the context of environmental impact assessments and strategic environmental assessments, a combination of all four FGs may provide a more informative tool than any single FG.

The present work was conducted in an area of cerrado sensu stricto in San Carlos, state of San Paulo, Brazil. It retracted the floral biology of Pyrostegia venusta, which isconsidered an invader creeper liana. We had done experimental crossings and nectar
collection, had observed the visitors, had described the flower morphology and had verifiedpollen viability. We have found a high number of abortions, which could be related to the low
pollen viability observed. The flower morphology indicates that hummingbirds should be theprincipal pollinator, the results we had obtained agreed whit that. We also detected that the
day period in which more birds visited the flowers coincided with the period of bigger nectarproduction. As a result we concluded that P. venusta invest a lot in the interaction with
hummingbirds in order to compensate the low viability of its pollen. The success of the plantseems to be a consequence of this strategy and vegetative reproduction.

The native distribution of the blue crab Callinectes sapidus in the western Atlantic extends from Nova Scotia to Argentina. Introduced to Europe at the beginning of the 20th century, it is currently recorded almost ubiquitously in the Mediterranean and in the Black Sea. An overview of the occurrence, abundance, and ecological impact of the species in southern European waters is provided; additionally, we present a pragmatic assessment of its management scenarios, explicitly considering the dual nature of C. sapidus as both an invasive species and a fishery resource. We emphasise that the ongoing expansion of C. sapidus in the region may represent a stimulating challenge for the identification and implementation of future strategies in the management of invasive crustaceans. The impact of the invader could be converted into an enhancement of the services delivered by southern European coastal ecosystems, while mitigation costs could be transformed into profits for local populations.

After removing invasive plants, whether by herbicides or other means, typical restoration design focuses on rebuilding native plant communities while disregarding soil microbial communities. However, microbial–plant interactions are known to influence the relative success of native versus invasive plants. Therefore, the abundance and composition of soil microorganisms may affect restoration efforts. We assessed the effect of herbicide treatment on phytosymbiotic pink-pigmented facultative methylotrophic (PPFM) bacteria and the potential consequences of native and invasive species establishment post-herbicide treatment in the lab and in a coastal sage scrub (CSS)/grassland restoration site. Lab tests showed that 4% glyphosate reduced PPFM abundance. PPFM addition to seeds increased seedling length of a native plant (Artemisia californica) but not an invasive plant (Hirschfeldia incana). At the restoration site, methanol addition (a PPFM substrate) improved native bunchgrass (Nassella...

Fifteen species of introduced ants, including eight cosmopolitan or tramp species, are recorded for the first time in the United Arab Emirates. They are Cardiocondyla emeryi, Camponotus compressus, Iridomyrmex anceps, Linepithema humile, Monomorium destructor, Monomorium indicum, Pachycondyla sennaarensis, Paratrechina flavipes, Paratrechina jaegerskioeldi, Paratrechina longicornis, Pheidole teneriffana, Solenopsis geminata, Tapinoma melanocephalum, Tapinoma simrothi and Tetramorium bicarinatum. A synopsis of their distribution, biology and pest status is given. Introduced species contribute an unusually high proportion of local ants and the ecological implications of their presence are discussed, including displacement of native fauna and impact upon human health. These ants abound in man-made, mesic environments and do not reach the characteristic sandy deserts of the region. Most invasive species are probably benign, but P.sennaarensis, M.destructor and S.geminata pose potential problems as public health and nuisance pests. The highly competitive S. geminata and L. humile may also threaten the local entomofauna and biodiversity.

Most atmospheric scientists agree that climate changes are going to increase the mean temperature in Europe with increased frequency of climatic extremes, such as drought, floods, and storms. Under such conditions, there is high probability that forests will be subject to increased frequency and intensity of stress due to climatic extremes. Therefore, impacts of climate change on forest health should be carefully evaluated. Given these assumptions, several fungal diseases on trees may become more devastating because of the following factors: (i) abiotic stresses, such as drought and flooding, are known to predispose trees to several pathogens; (ii) temperature and moisture affect pathogen sporulation and dispersal, and changes in climatic conditions are likely to favour certain pathogens; (iii) migration of pathogens triggered by climatic change may increase disease incidence or geographical range, when pathogens encounter new hosts and (or) new potential vectors; and (iv) new threats may appear either because of a change in tree species composition or because of invasive species. If infection success is dependent on temperature, higher mean temperatures may lead to more attacks. Pathogens that have been of importance in southern Europe may spread northward and also upward to mountains. Pathogens with evolutionary potential for greater damage should be identified to estimate the magnitude of the threat and to prepare for the changing conditions. A review of the above-mentioned cases is presented. Some priorities to improve the ability to predict impacts of climate change on tree diseases are discussed.

Tributaries of the Colorado River Basin, historically home to a complex of endemic omnivores collectively referred to as the 'three species'; flannelmouth sucker (Catostomus latipinnis), bluehead sucker (C. discobolus) and roundtail chub (Gila robusta), have experienced the establishment of numerous non-native fish species. In this study, we examine the impacts of the trophic ecology of non-native fishes on the 'three species' in the San Rafael River, Utah, USA. We employ a suite of abundance comparisons, stable isotope techniques and size-at-age back-calculation analyses to compare food web structure and growth rates of the 'three species' in study areas with and without established populations of non-native species. We found that the 'three species' are more abundant in areas with few non-native fishes present, regardless of habitat complexity. Stable isotope analyses indicate non-native fishes lengthen the food chain by 0.5 trophic positions. Further, the trophic niche spaces of the native fishes shift and are narrower in the presence of non-native fishes, as several non-native species' trophic niche spaces overlap almost entirely with each of the 'three species' (bluehead sucker and flannelmouth sucker 100%, roundtail chub 98.5%) indicating strong potential for competition. However, the 'three species' demonstrated no evidence of reduced growth in the presence of these non-native fishes. Collectively, these results suggest that while non-native fishes alter the food web structure presenting novel sources of predation and competition, mechanisms other than competition are controlling the size-structure of 'three species' populations in the San Rafael River.

Myths about invasive species are widespread in the general community, even when contrary to scientific evidence. Public revulsion against invasive cane toads (Bufo marinus) in Australia has encouraged the belief that toads pose a
significant risk to domestic poultry, by poisoning fowls that eat toads or that drink water contaminated by toads. Although discredited by scientists in 1938, within 2 years of the toads’ introduction to Australia, the myth continues to flourish. We conducted experimental trials to evaluate the vulnerability of chickens to toad-contaminated water, and to toad ingestion. No ill effects were seen, with one chicken consuming 45 small toads without falling ill. Thus, available evidence suggests that cane toads do not imperil domestic poultry.

We review plant conservation in the Mascarenes (Reunion, Mauritius, Rodrigues) and the granitic Seychelles islands. Sizes of angiosperm floras are: Seychelles (200 species, c. 70 endemics of which c. 70% are threatened), Mauritius (691 species of which 273 are single island endemics [SIE] and another 150 are Mascarene endemics [ME]), Rodrigues (150 species, 47 SIE, 72 ME), Reunion (550 species, c. 165 SIE, c. 140 ME). The main threats affecting plant diversity are small population sizes and fragmentation, and invasive alien species. While in Mauritius, Rodrigues and Seychelles <5% of intact habitat is left, this proportion is still 30% in Reunion. Consequently habitat restoration is a priority in Mauritius, Rodrigues and Seychelles. All islands have recently greatly advanced some aspects of plant conservation, while gaps are also apparent. Advances include conservation strategies (all), ex situ conservation (all), extent of protected areas (Reunion, Seychelles), new NGOs (Reunion...

The study examined the Air Pollution Tolerance Index (APTI) of seven different tree species growing around electricity generating houses within the Ahmadu Bello University (ABU) Main campus, Samaru. Four parameters, leaf relative water content (RWC), ascorbic acid content (AA), total chlorophyll (TCH) and pH of leaf extract were used to compute the APTI of the tree species. Results indicate the order of tolerance showing Azadirachta indica (9.8) < Carica papaya (11.5) < Albizia lebbeck (14.9) < Senna siamea (17.0) <Mangifera indica (17.8) <Khaya senegalensis (19.5) < Termonalia collii (20.9). Terminalia collii, the most tolerant could act as a possible sink for air pollutants around pollution emitting sources. On the other hand, A. indica, the most sensitive of the studied species could serve as a possible indicator of air pollution.

The problem of invasive species spread requires timely analysis of the biological dynamics that lead to spatial dispersion. Here, a spatial dynamic model captures the invasive behavior of the recently introduced emerald ash borer (EAB) (Agrilus planipennis) and its impacts on host ash (Fraxinus spp.) trees. Parasite-host system dynamics are extended spatially using the Spatial Modeling Environment. The resulting model can serve as a repository for changing knowledge about EAB biology and behavior. Studies of the rapid EAB infestation in Michigan are used to inform simulations of its spread in DuPage County, Illinois, USA. We use a geographic information system to create heterogeneous host landscapes and to test alternative policy scenarios. We test the effectiveness of three suppression scenarios: the Michigan eradication strategy, firewood quarantines, and ash tree thinning. Simulations demonstrate that EAB spatial spread accelerates with degraded host capacity, with results pointing to firewood quarantines as the most effective solution.

Mapping the cover of invasive species using remotely sensed data alone is challenging, because many invaders occur as mid-level canopy species or as subtle understorey species and therefore contribute little to the spectral signatures captured by passive remote sensing devices. In this study, two common non-parametric classifiers namely, the neural network and support vector machine were used to map four cover classes of the invasive shrub Lantana camara in a protected game reserve and the adjacent area under communal land management in Zimbabwe. These classifiers were each combined with a geographic information system (GIS) expert system, in order to test whether the new hybrid classifiers yielded significantly more accurate invasive species cover maps than the single classifiers. The neural network, when used on its own, mapped the cover of L. camara with an overall accuracy of 71% and a Kappa index of agreement of 0.61. When the neural network was combined with an expert system, the overall accuracy and Kappa index of agreement significantly increased to 83% and 0.77, respectively. Similarly, the support vector machine achieved an overall accuracy of 64% with a Kappa index of agreement of 0.52, whereas the hybrid support vector machine and expert system classifier achieved a significantly higher overall accuracy of 76% and a Kappa index of agreement of 0.67. These results suggest that integrating conventional image classifiers with an expert system increases the accuracy of invasive species mapping.

All else being equal, the faster an invading species spreads, the more dangerous its invasion. The projection of spread rate therefore ought to be a central part of the determination of invasion risk. Originally formulated in the 1970s to describe the spatial spread of advantageous alleles, integrodifference equation (IDE) models have since been co-opted by population biologists to describe the spread of populations. More recently, they have been modified to include population structure and environmental variability. We review how IDE models are formulated, how they are parameterized, and how they can be analyzed to project spread rates and the sensitivity of those rates to changes in model parameters. For illustrative purposes, we apply these models to Cytisus scoparius, a large shrub in the legume family that is considered a noxious invasive species in eastern and western North America, Chile, Australia, and New Zealand.

A population of a non-indigenous armoured catfish Pterygoplichthys aff. pardalis from the Dinh river basin (Khan Hoa province, Vietnam). We provide evidence that this is a fully naturalised self-reproducing population and present data on its reproduction. Batch spawning is noted. Possible threat presented by this population to the native habitat and its inhabitants is discussed along with its possible fate. We also analysed the patterns of the fish colouration, which is the main character used for the identification of the species of this genus. We provide evidence that morphometric traits and patterns of the body colouration do not form discrete clusters. Therefore, systematics of the genus should be revised and several species would likely be invalid.

Successful overwintering of a coccinellid species is partially dependent on quality of hibernacula, for surviving cold temperatures, for drowning risk, and for avoiding parasitism or infection by pathogens. The multicolored Asian lady beetle, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), an introduced species that has spread throughout North America since 1988, overwinters outside and inside houses or artiÞcial structures. Five experiments were conducted during winter 2003Ð2004 to evaluate winter survival of the invasive H. axyridis compared with the indigenous Coleomegilla maculata lengi Timberlake outside and inside human houses, to assess its contribution to the invasive success of the multicolored Asian lady beetle. We formulated the hypothesis that H. axyridis will survive during winter inside human houses and that no survival would be observed outside in Quebec, Canada. Survival of H. axyridis ranged from 25 to 53% in different experiments inside houses, whereas no survival was recorded outside. C. maculata did not survive inside houses, but 12.5% of the individuals survived outside. The indigenous species C. maculata had higher proportion of lipids than the invasive species H. axyridis, suggesting that H. axyridis is not physiologically adapted to overwinter in Canada. Selection of human houses as overwintering sites by the multicolored Asian lady beetle may constitute a "cold-free space," which could explain its great invasive success in northern regions.

Ailanthus altissima (tree of heaven) is a non-native invasive tree spreading within central Appalachia. This dioecious, deciduous, and allelopathic species copiously produces samaras, capable of traveling at least 200 m through primary wind-dispersal. Removal of A. altissima individuals prior to timbering and other forest disturbances may help prevent spread into forest interiors. To aid in species management, this study investigated the use of remote sensing to identify the location and abundance of samaras in mixed mesophytic forests through supervised classifications. From empirical measurements, the estimated number of seeds per classified unit area was determined and the relationship between quantified propagule sources and individual seed primary dispersal was spatially modeled using a cellular automata model. The predicted seed dispersion pattern was compared to empirical seed trap measurements. Secondary seed dispersal, germination and seedling survival parameters were determined through field experiments. Specifically, I found that remote sensing can be successfully used to distinguish A. altissima samara clusters from surrounding closed canopy vegetation. The identified total area of classified A. altissima samara clusters was determined to be linearly related to total canopy seed yield, however model predictions of seed dispersal patterns generally predicted greater numbers of seeds per seed trap compared to measured outcomes. Seed dispersal predictions using all classified A. altissima samara clusters provided no positive relationships with observed values (Site II, p=0.2997; negative relationship at Site III, p=0.0053). Manually delineating seed sources through photo interpretation resulted in a positive relationship between model estimates and observed seed rain (Site II, p=0.0225), but may still contain commission errors (Site III, p=0.7002). Microsite survey observations of seed germination indicate the frequency of safe sites was high in disturbed environments (canopy gaps), but seedling survival was negligible in the year this study was performed. Measurements of secondary dispersal on land and water (hydrochory) indicate the species can be dispersed with multiple dispersal agents. Hydrochory was shown to be able to contribute greatly to the species’ long distance dispersal, as seeds can reach water bodies, stay viable for long periods of immersion, and can be dispersed downstream distances more than two orders of magnitude greater than primary dispersal. This was the first demonstration of hydrochory in this species. From these studies, it appears that polychory may contribute greatly to this species dispersal and I can infer the same polychory occurs in other terrestrial species, and may contribute to invasive success.

English broom (Cytisus scoparius) is an aggressive invasive shrub in native sclerophyll forests of South Australia. We studied its relative growth rate (RGR) and competitive ability in soils from invaded and uninvaded woodlands, in comparison to three native species it commonly displaces:Hakea rostrata, Acacia verniciflua, and A. myrtifolia. Hakea was the slowest growing species throughout the year. Both native species had their highest RGR during spring. The RGR of broom was higher than that of both hakea and acacia in the winter and spring. Despite losing its leaves in the summer, the RGR of broom through the year was higher than that of either of the native species. Soil from the invaded stands had higher organic C, N and soluble P than that from uninvaded sites. Broom and acacia grew better in the higher nutrient soil than in the lower nutrient soil. Competition did not decrease the final biomass of any of the species in low nutrient soil. In the higher nutrient soil the biomass of broom was reduced by competition with acacia, but not by competition with hakea. Competition by broom reduced the biomass of hakea but not that of acacia. Broom's earlier and higher RGR, high competitiveness in nutrient rich soils, and probably its ability to change nutrient availability could be important contributors to the mechanisms by which it invades native woodlands.

The allelopathic effects of fresh shoot aqueous extract of Tithonia diversifolia (Hemsl.) A.Gray, an invasive species introduced into Africa from North and Central America, on the growth of seedlings of three woody species: Monodora tenuifolia, Dialium guineense and Hildegardia barteri were investigated. The fresh shoot aqueous extract of Tithonia diversifolia was applied to the established seedlings of the three woody species over a period of ten weeks. The fresh shoot aqueous extract of Tithonia diversifolia had a significant effect (inhibitory and stimulatory) on growth parameters such as shoot height, leaf area, number of leaves and chlorophyll content of the three woody species. The study revealed that the fresh shoot aqueous extract of Tithonia diversofolia have different effects (inhibitory and stimulatory) on the seedlings and the mode of action depends on the associated woody plant species.

When a community or ecosystem is lost, some of its properties may remain, leaving behind an ecological memory. The soil properties, spores, seeds, stem fragments, mycorrhizae, species, populations and other remnants of the previous inhabitants contribute to shaping the replacement community and building a new ecosystem. The loss of ecological memory for the natural stability domain of a site reduces ecosystem resilience and enables alien invasive species to become established more easily. These invasives may eventually create a new ecosystem with its own ecological memory and resilience. These new ecosystems are described here as novel ecosystems and are placed in the context of adaptive cycles. Ecological restoration of urban ecosystems requires removing the ecological legacy of invasive alien species. To be successful, invasive species control must address both internal within patch memory of invasives and external between patch memory. The restoration of Garry oak ecosystems (Quercus garryana), by students of the Restoration of Natural Systems Program at the University of Victoria, British Columbia, and a number of other examples are presented here that highlight why ecological memory is especially important in urban ecosystems.

Anoplophora glabripennis (Motschulsky) (Coleoptera: Cerambycidae), an invasive pest quarantined in the United States, is difÞcult to detect because the larvae feed unseen inside trees. Acoustic technology has potential for reducing costs and hazards of tree inspection, but development of practical methods for acoustic detection requires the solution of technical problems involving transmission of resonant frequencies in wood and high background noise levels in the urban environments where most infestations have occurred. A study was conducted to characterize sounds from larvae of different ages in cambium, sapwood, and heartwood of bolts from three host tree species. Larval sounds in all of the tested trees and tissues consisted primarily of trains of brief, 3Ð10-ms impulses. There were no major differences in the spectral or temporal pattern characteristics of signals produced by larvae of different ages in each tissue, but larval sounds in sapwood often had fewer spectral peaks than sounds in cambium and heartwood. A large fraction, but not all background sounds could be discriminated from larval sounds by automated spectral analyses. In 3-min recordings from infested bolts, trains containing impulses in patterns called bursts occurred frequently, featuring 7Ð 49 impulses separated by small intervals. Bursts were rarely detected in uninfested bolts. The occurrence of bursts was found to predict infestations more accurately than previously used automated spectral analyses alone. Bursts and other features of sounds that are identiÞable by automated techniques may ultimately lead to improved pest detection applications and new insight into pest behavior.