The Australian bee Hylaeus ( Gnathoprosopis ) euxanthus (Hymenoptera: Colletidae) in Argentina: Nesting biology, floral preferences and parasitism

Use of reed stalk trap nests by insects within the reed beds and in nearby steppic habitats

Biological invasions are regarded as one of the main drivers of habitat degradation in island ecosystems. Mediterranean islands have been subjected to a high degree of land conversion over the past 60 years, resulting in a massive reduction in the amount of rural land and the sprawl of tourist activities. The aims of this paper are to evaluate the current level of invasion of alien plant species in semi-natural vegetation types that have developed after the abandonment of agriculture and to analyze the relationships between non-native species, native flora, and environmental characteristics. Two Italian islands (Ponza and Ventotene) were surveyed using a random-stratified sampling. The occurrence and relative cover of alien plant species were compared and separate analyses were performed for the native flora. Abundance patterns of both native and alien species were then studied in the light of the environmental and anthropogenic features. Although we found that some non-native species are extremely widespread, their relative cover at the plot level is low. Permutational Multivariate Analysis of Variance and Indicator Species Analysis revealed dissimilarities in the native species composition, while Mann–Whitney and Kruskal–Wallis tests showed differences in the ecological requirements (moisture, soil reaction, and nitrogen) of the native species pool. Canonical Correspondence Analysis pointed to the importance of the proximity to agricultural areas, human disturbance, and past land management, particularly residual terraces, in determining the difference between plant communities on the two islands. The results of our study suggest that traditional forms of agriculture may represent a key element for countering the establishment and spread of non-native plants in Mediterranean areas.

Invasive exotic (alien) species have not been taken into enough consideration concerning the European Water Framework Directive (WFD) and other European directives until recently. The Dutch ministry responsible for water management is looking for ways to establish the impacts that invasive alien species may have on specified water types. This paper concentrates on the vulnerability of such water types to the introduction of exotic species. This new approach focusses on the system where the alien species are introduced into rather than only on the alien species themselves. We propose an equation that combines threats to and in water types with effects of particular species (observed or prognosticated). Numerical values used in the formula have been found by scoring a number of properties in different water types and species, which are specified in questionnaires. The results of the calculations are given as relative vulnerability scores (scale 1–10). By testing as many as 8 water types and 13 species, we demonstrate that this method is flexible and easy to use for water managers. Our results can be translated into classes of vulnerability, which are represented on geographical maps with colour codes to indicate different degrees of vulnerability in the different water bodies. This readily corresponds to the way countries are required to report to the European Union in the context of the WFD. The method can also be generalized using functional groups of (exotic) species instead of particular species.

Obtaining colonies of stingless bees in the wild for the formation or expansion of meliponaries and other purposes is permitted by law in Brazil using bait containers or trap nests, and other non-destructive methods. We tested the efficiency of trap nests made from plastic bottles for attraction and nesting of stingless bees in the central Brazilian Amazon. We used 2-L and 5-L bottles and three types of attractants (cerumen and geopropolis from Melipona seminigra, M. interrupta and a mix of the two). We used 216 trap nests distributed in three experimental areas during 13 months. Visitation by six species of stingless bees in 58 (26.9%) trap nests, and nesting by three species in 12 (5.6%) trap nests in two areas near meliponaries was recorded. There was no significant difference between trap-nest size, nor among attractants for visitation or nesting, suggesting that the availability of cavities or hollows is more important than odor for nesting. Monthly pooled visitation and nesting events were not correlated with monthly rainfall. Based on our results, we can conclude that, despite the low capture rate, the acquisition of swarms through nest traps is a viable alternative to obtain new colonies of stingless bees for meliponaries.

Biological invasions are synonymous with international trade. The direct effects of trade have largely been quantified using relationships between imports and the number of alien species in a region or patterns in the global spread of species linked to shipping and air traffic networks. But trade also has an indirect role on biological invasions by transforming the environments and societies of exporting and importing nations. Here, both the direct and indirect roles of trade on biological invasions, as well as their interaction, are examined for the first time. Future trends in international trade, including e-commerce, new trade routes, and major infrastructure developments, will lead to the pressure on national borders soon outstripping the resources available for intervention. The current legislative and scientific tools targeting biological invasions are insufficient to deal with this growing threat and require a new mindset that focuses on curbing the pandemic risk posed by alien species.

Much has been written about the influence of exotic or nonindigenous species on natural habitats and communities of organisms, but little is known of the physical or biological conditions that lead to successful invasion of native habitats and communities by exotics. We studied invasivity factors in headwater streams of the Susquehanna River West Branch, which drains portions of the northern Appalachian Plateau. A replicated (two major tributaries) 3 × 3 factorial design was used to determine landscape effects of size (stream order) and quality (land use) on abiotic (physical and chemical) and biotic (fish community structure and function) stream attributes. Seven (21%) of thirty-four fish species (brown trout, common carp, mimic shiner, bluegill, smallmouth bass, fantail darter, and banded darter) collected in the eighteen streams sampled were nonindigenous to the basin. Watershed size (stream orders 1, 3, and 5) significantly affected stream geomorphologic and habitat variables (gradient, width, depth, current velocity, diel water temperature, bank overhang, canopy cover, and woody debris density) but not water-quality variables, while land use in watersheds (conservation, mining, and agriculture) significantly affected measured water-quality variables (alkalinity and concentrations of manganese, calcium, chloride, nitrate, and total dissolved solids) but not stream physical or habitat quality. Both watershed size and land use affected fish-community variables such as presence of particular species, species density, species diversity, tolerance diversity, and mean fish size, but in both cases the effect was transparent to native-origin status of fish species. No relationships were found between occurrence of nonindigenous species in watersheds and trophic structure or functional diversity. Therefore, the hypothesis that reduced species diversity increases vulnerability to nonindigenous species was not supported. However, the spatial variation associated with both water-quality and habitat-quality factors was greater in streams with mixed (those with nonindigenous species) than with exclusively native assemblages. These findings suggest that the mechanism for successful invasion by nonindigenous or exotic species is through change in water or habitat quality associated with human or natural disturbances, such as agriculture and mining activities in watersheds. Biotic factors appear to play no or a lesser role in the invasibility of northern Appalachian lotic systems.

BackgroundUrban forests are under increased pressure from invasion by exotic (alien) species. The vegetation present in the matrix of urban sites is a rich source of alien invasive propagules, which increases the risk of alien invasion in forests within an urban space, leading to a decline in indigenous species. Therefore, determining the distribution patterns of native and exotic species as influenced by environmental factors can assist in quantifying the impact of exotic species at broad scales based on responses on a finer scale. Quantifying the effects of multiple environmental factors on the distribution patterns of both indigenous and alien species in the ecosystem may help in prescribing suitable management efforts.MethodsFifteen forest patches were sampled in the eThekwini (Durban) Municipality and data collected from 74 100-m2 plots with different degrees of invasion. Indigenous and alien species of trees, shrubs and climbers occurring in ten and more plots were considered for analysis and the CANOCO 5.1 package was used to run various constrained ordination analyses. Variation partitioning analysis was used to assess the impact of environmental variables at different spatial scales, namely the plot and patch scales.ResultsCanopy gaps are the major controlling factor for invasive alien plants (IAPs) occurrence at fine scale. At patch level, residential and industry areas outside the boundaries (buffer area) of forest patches have a high influence on the distribution of IAPs. Communities dominated by the invasive Chromolaena odorata (L.) R.M. King are most common on the lowland coastal forests while communities dominated by either Litsea glutinosa (Lour.) C.B.Rob. or Cardiospermum grandiflorum Sw. can prevail in both lowland coastal and scarp forests.ConclusionsCanopy gaps in lowland forests can facilitate the transition of native forests to novel communities containing a variety of alien plant species. Communities of shrub, climber and tree IAPs occur in lowland coastal forests while climber and tree IAPs dominate the high-elevation scarp forests. The resilience shown by some native species to the tree, shrub and climber IAPs by remaining when IAPs establish makes these species very suitable for restoration projects. Forest patches surrounded by a high incidence of residential and industrial areas in the buffer matrix are likely to have a high diversity of IAPs. Larger patch size and high connectivity to nearby native forests are key in reducing invasion by IAPs.

Due to potential impact of invasive alien (exotic) species to the natural ecosystems, inventory of exotic species in the Cibodas Botanic Gardens (CBG) remnant forest area is an urgent need for CBG. Inventory of exotic species can assist gardens manager to set priorities and plan better responses for possible or existed invasive plants in the CBG remnants forest. The objectives of this study are to do inventory of the exotic species in the CBG remnant forest and to determine whether several environmental variables play role to the existence of exotic species in the CBG remnant forests. There are 26 exotic plant species (23 genera, 14 families) found and recorded from all four remnant forests in CBG. Cluster analysis of four environmental variables shows that clustering of environmental factors of exotic species correlates with the abundances of those exotic species. The relation between environmental factor clusters and the abundance of those exotics signify the role of environmental variables on the existence of exotic plant species. The information of exotic plant species in the remnants forest is the base information for gardens manager to manage exotic species in CBG remnants forest. The relation of several environmental factors with exotic species abundance could assist gardens manager to understand better the supportive and or suppressor factors of exotics in the CBG remnants forest. Further study on these species is needed to set priorities to decide which species should be treated first in order to minimize the impact of exotic plant species to native ecosystem of CBG.

When organisms are moved from their natural range to new ecosystems, they are considered nonindigenous, invasive, or exotic species. Movement of exotic or native species may be international or from areas within Canada. Historically, Canada's forests have felt the effects of nonindigenous species introductions, as for example, Dutch elm disease, white pine blister rust, gypsy moth, and pine shoot beetle. With changes in global trade patterns, novel introductions will continue to occur. Although most of the research and regulatory efforts to control the movement of nonindigenous species has focused on insects, projects are underway to study fungal organisms and their association with insect vectors. International quarantine standards are being developed to minimize the risk associated with solid wood packing materials, a major entry pathway for nonindigenous organisms. Research needs include the development of enhanced detection capabilities, improved diagnostic tools, effective mitigation measures, as well as socio-economic impact assessments and basic biological information about nonindigenous species and their interactions with hosts.

A rating system for potential exotic bird and mammal pests

The last decade has seen a rapid development of scientific, logistic and tourist activities, especially in the Antarctic region with the mildest climatic conditions: the Antarctic Peninsula. This region is also exhibiting rapid regional warming and all of the already diagnosed alien species in the Antarctic Treaty Area were found within the Antarctic Peninsula. Identifying potential invasive species that can threaten this pristine area of the Earth helps us to take specific preventive actions. This article is a commentary on Hughes et al., 26, 2702-2716.

Simple SummaryIsland environments of the Southwest Pacific, like New Caledonia, generally present poorly diversified bee fauna. Thus, they are particularly prone to the establishment of introduced bee species. These exotic species may compete with native bees for plant resources, disrupt pollination of native plants, and enhance the reproduction of exotic ones. To conserve local plant–pollinator interactions, it is essential to assess the factors favoring the presence and the activity of exotic bees. Here, we focused on the effects of urbanization on plant–pollinator interactions. We set up experimental plant communities composed of four exotic species in two contrasted habitats—a natural environment vs. an urban environment—and observed plant–pollinator interactions. We showed that the urban environment was largely dominated by exotic bees. We also showed that some exotic bee species can interact preferentially with a single exotic ornamental plant species. Overall, our results indicate that Nouméa is an entry point for exotic bees, which should encourage local authorities to maintain biosecurity measures to effectively limit the arrival of exogenous bees. Lastly, the use of exotic horticultural plants in green public spaces should be questioned regarding their potential attractiveness to exotic bees.Land-use changes through urbanization and biological invasions both threaten plant-pollinator networks. Urban areas host modified bee communities and are characterized by high proportions of exotic plants. Exotic species, either animals or plants, may compete with native species and disrupt plant–pollinator interactions. These threats are heightened in insular systems of the Southwest Pacific, where the bee fauna is generally poor and ecological networks are simplified. However, the impacts of these factors have seldom been studied in tropical contexts. To explore those questions, we installed experimental exotic plant communities in urban and natural contexts in New Caledonia, a plant diversity hotspot. For four weeks, we observed plant–pollinator interactions between local pollinators and our experimental exotic plant communities. We found a significantly higher foraging activity of exotic wild bees within the city, together with a strong plant–pollinator association between two exotic species. However, contrary to our expectations, the landscape context (urban vs. natural) had no effect on the activity of native bees. These results raise issues concerning how species introduced in plant–pollinator networks will impact the reproductive success of both native and exotic plants. Furthermore, the urban system could act as a springboard for alien species to disperse in natural systems and even invade them, leading to conservation concerns.

<p>Coastal environments are exposed to anthropogenic activities such as frequent marine traffic and restructuring, i.e., addition, removal or replacing with man-made structures. Although maritime shipping and coastal infrastructures provide socio-economic benefits, they both cause varied perturbations to marine ecosystems. The ports and marinas receiving a high frequency of international vessels, act as ‘hot-spots’ for marine invasions. The disturbed and modified habitats found in harbours and ports provide opportunities for non-native species to settle due to their competitive traits. Once established, the non-native species may spread to neighbouring habitats, thereby modifying the adjacent natural environment, its biodiversity, ecosystem structure and functioning. Up to 70% of coastlines around the world have now been modified and is expected to rise in future. New bioinvasions are still being reported even with various biosecurity and management approaches across the globe. It is essential to understand the potential factors influencing the bioinvasions to have effective biosecurity measures and management plans. The overall aim of this thesis is to determine the influence of man-made structures on the marine biodiversity and presumptive fitness of native and non-native species on these structures. This thesis investigates ports and harbours as man-made environments, their impacts on marine biodiversity and the species status – native, non-native and cryptogenic, and the factors facilitating the spread of non-native species. Chapter 2 focussed on two large national-scale baseline port surveys; a) Australian Port Survey (APS), and b) New Zealand Port Survey (NZPS). The two datasets were analysed to determine the community structure and species status, i.e., native, non-native and cryptogenic as a function of the surveyed ports, port type (major vs minor ports) (based on the volume of vessels) and latitudinal groups. A) APS: The results for community composition indicated significant effects as a function of surveyed ports, port type and latitudinal group. The community composition was relatively more abundant at major ports than at minor ports. The factor, the latitudinal group indicated significant results, and a distinct separation in community composition was observed between low (15, 20oS) and high (35, 40oS) latitudes. The species status showed a significant and positive relationship between native vs non-native, indicating with an increase in the number of native species there was an increase in the number of non-native species. The species status indicated significant results for the factors; surveyed ports, port type and latitudinal group. The native species were abundant throughout the study. However, the non-native species were relatively abundant at major ports compared to minor ports. Regarding the latitudinal groups, the abundance of non-native species was observed to increase at higher latitudes (latitudinal gradients). B) NZPS: The community composition and species status showed significance among the 27 surveyed ports; however, no significant results were observed for the factor port type (major vs minor). The community composition significantly varied as a function of latitudinal groups, with species at higher latitudes (45oS) being better discriminator explaining the differences. Latitudinal groups, however, highlighted sub-groupings of ports with similar community composition (e.g. Bluff and Dunedin; Nelson, Wellington and Picton; Lyttelton and Timaru; Whangarei, Tauranga and Taranaki; Auckland, Gulf Harbour Marina and Opua Marina). The ports in question are within close proximity of each other (distance). This suggests the possibility of natural dispersal of species between ports on top of the human-mediated dispersal. The responses in Australia were very different from those in New Zealand, which suggests that the responses are regional or country-specific and not global. Chapter 3 describes fieldwork using settlement tile arrays to examine the effects of man-made built structures and natural rocky reefs on marine biological community composition and successional patterns over two years. The work also tests the preference of native and non-native species in terms of habitat type (natural reef vs man-made habitat) and substratum type (PVC vs slate tile). The results showed a rapid increase in species settlement on bare tiles as the available bare space was 30% just after 3 months of submersion. The community composition significantly differed as a function of the interaction of factors, habitat × substratum × sample interval. However, differences between the habitat types and substratum types, respectively, were explained by the difference in abundance of the same suite of species. The species were abundant at marina sites compared to reef sites; however, in terms of substrata, the species were abundant on slate (natural) tiles than on PVC tiles. The succession patterns of species over time (8 sample intervals) showed a similar trend on both the habitat type and substratum type, with differences in the average abundances of each species. The differences in abundances highlight the influence of species dispersal patterns, recruitment patterns and post-settlement processes of species between habitat type and substratum type, respectively. Subsequently, the species status indicated significance as a function of habitat type, substratum type and sample intervals. The cryptogenic species were abundant throughout the study. The cryptogenic species, however, decreased in abundance over time, with an increase in abundance of native and non-native species. Subsequently, the non-native species significantly varied between habitat type, with relatively higher abundance at marina (man-made) sites compared to reef (natural) sites. However, the non-native species did not show significant variation as a function of substratum type (PVC vs slate). The results are discussed in the context of the recruitment of species on a new barren substrate, and the preference of habitat type and substratum type by native, non-native and cryptogenic species. In Chapter 4, the reproduction output (gonadosomatic index, GSI) of the Southern hemisphere, native (SHMg) and Northern hemisphere, non-native (NHMg) lineages of the blue mussel, Mytilus galloprovincialis were measured. The GSI and shell length of NHMg and SHMg were compared between habitat type; reef (natural) vs marina (man-made) sites. This study aimed to identify reproductive patterns (i.e., timing and magnitude of spawning events) and differences in performance (presumptive fitness) of the native and non-native blue mussel lineages at the natural and man-made habitats. The results for shell length indicated significance for habitat type and no significance as a function of lineage. The mussels were relatively bigger mussels at marina sites compared to reef sites; however, the differences were trivial. The GSI values as a function of habitat type, lineage and sampling time showed a significant difference between habitat type, with high GSI values at reef sites than at marina sites. However, this indicates that the blue mussels at marina sites had comparatively higher spawning activity than at reef sites. The temporal variation of GSI of NHMg and SHMg showed a similar reproductive trend (i.e., spawning and gametogenesis) at both habitats. However, significant spawning activity was observed in July and November when compared between reef and marina habitats. The results are discussed in the context of management implications and strategies regarding the establishment and success of non-native M. galloprovincialis lineage and whether their eradication is necessary or even possible. The findings of this research are summarised and discussed in relation to our understanding of biological community composition and diversity on man-made habitats and the subsequent invasion in the neighbouring natural habitats. This study, from an eco-engineering perspective, highlights the importance of complex habitats and surfaces, and not just material type. However, from a biosecurity and management approach, even though Australia and New Zealand have one of the strong international biosecurity country-specific legislation; the continuous arrival of non-native species in these countries indicates that such marine legislation is not sufficiently compelling on its own. This study highlights the interaction of non-native species at proximity ports, and it provides recommendations towards regional-scale management measures concentrating on intra-coastal transfer of invaders through domestic maritime traffic or natural dispersal. The life-history traits, recruitment timing and post-settlement processes, plays an essential role in determining long term patterns. Lastly, this research indicated that native and non-native species with ecologically similar responses lead to limited management options to some extent. Therefore, from a manager’s perspective, the eradication of non-native species may not be necessary if it does not cause any negative impacts to the biodiversity or the environment.</p>

Alien species, after becoming locally dominant, invade natural communities and become Invasive Alien Species (IAS). The impacts of exotic plants on community structure and ecosystem processes are poorly understood in India. A total 173 species in 117 genera are invasive alien plants, representing 1 % of the Indian flora. The agricultural economy in India is vulnerable to threat from exotic pests/ diseases. In India, 116 alien insect species mainly belong to the order Coleoptera and Lepidoptera. Over 300 alien fish species including 291 ornamental species, 31 aquaculture species and 2 larvicidal fishes are recorded. Examining the ecology and genetic make-up of the IAS is important for developing management strategies. Monitoring of invasion can be done through species inventory, phyto-sociological methods, mapping using ground-based methods, and remotely-sensed images. The Government of India in 2003 has approved the notification of a new plant quarantine order harmonizing India’s regulatory framework with the International plant protection convention and internationally accepted standards and the tenets of the SPS agreement of the World Trade Organization. Community based approaches, for alien species management, can best be complemented with biological control. Brief description of alien species and their present management strategies in India are discussed in this communication along with a note on strengthening the said strategy. Key words: Anthropogenic activities, threat to biodiversity, prevention, detection, eradication.

Human activity is creating a global footprint by changing the climate, altering habitats and reshuffling the distribution of species. The movement of species around the globe has led to the naturalization and accumulation of multiple non-native species within ecosystems, which is frequently associated with habitat disturbance and changing environmental conditions. However, interactions among species will also influence community composition, but little is known about the full range of direct and indirect interactions among native and non-native species. Here, we show through a meta-analysis of 1,215 pairwise plant interactions between 274 vascular plant species in 21 major habitat types that interactions between non-native plants are asymmetrical with interactions between non-native and native plants. Non-native plants were always bad neighbours, but the negative effect of non-natives on natives was around two times greater than the effect of non-natives on other non-natives. In contrast, the performance of non-native plants was five times higher in the presence of a neighbouring native plant species than in the presence of a neighbouring non-native plant species. Together, these results demonstrate that invaded plant communities may accumulate additional non-native species even if direct interactions between non-natives species are negative. Put another way, invasions may be more likely to lead to more invasions, requiring more active management of ecosystems by promoting native species restoration to undermine invasive positive feedback and to assist native species recovery in invaded ecosystems.