Vincetoxicum rossicum is an invasive alien vine introduced from Europe in the late 1800s that is now an emerging pest in upstate New York and eastern Ontario. The plant can form dense, monotypic stands in woodlots and old fields, and may be displacing native vegetation. As a consequence, V. rossicum may be displacing arthropod fauna associated with native vegetation. In June and August 2002, we sampled V. rossicum and three other old field plants (Asclepias syriaca, Solidago altissima, and mixed graminoids) for arthropods using pitfall traps and by sampling individual plants. A total of 7868 arthropods were counted on plants and 18,195 individuals were trapped; these were sorted by feeding guild. Overall, stands of V. rossicum supported the lowest abundance of both stem-and ground-dwelling individuals, as well as the lowest number of arthropods in most phytophagous guilds. Some feeding guilds are entirely absent: V. rossicum stands are completely devoid of gall-makers and miners, and support few pollinators. This study suggests that arthropod diversity will decline if V. rossicum displaces native old-field plants.

Many macroecological patterns of biodiversity, including the relationship between latitude and species richness, are well-described. Data collected in a repeatable, standardized manner can advance the discipline beyond the description of patterns and be used to elucidate underlying mechanisms. Using standardized field methods and a hyper-diverse focal taxon, viz. Coleoptera, we aim to (1) describe large-scale latitudinal patterns of taxonomic diversity, functional diversity, and assemblage structure across northern Canada, and (2) determine which climatic, spatial, and habitat variables best explain these patterns. We collected terrestrial beetles at twelve locations in the three northernmost ecoclimatic zones in North America: north boreal, subarctic, and high arctic (51–81°N, 60–138°W). After identifying beetles and assigning them to a functional group, we assessed latitudinal trends for multiple diversity indices using linear regression and visualized spatial patterns of assemblage structure with multivariate ordinations. We used path analysis to test causal hypotheses for species and functional group richness, and we used a permutational approach to assess relationships between assemblage structure and 20 possible climatic and environmental mechanisms. More than 9,000 beetles were collected, representing 464 species and 18 functional groups. Species and functional diversity have significant negative relationships with latitude, which are likely explained by the mediating effects of temperature, precipitation, and plant height. Assemblages within the same ecoclimatic zone are similar, and there is a significant relationship between assemblage structure and latitude. Species and functional assemblage structure are significantly correlated with many of the same climatic factors, particularly temperature maxima and minima. At a large spatial extent, the diversity and assemblage structure of northern beetles show strong latitudinal gradients due to the mediating effects of climate, particularly temperature. Northern arthropod assemblages present significant opportunities for biodiversity research and conservation efforts, and their sensitivity to climate make them ideal targets for long-term terrestrial diversity monitoring.

The classical theory of island biogeography , which predicts species richness using island area and isolation, has been expanded to include contributions from marine subsidies, i.e. subsidized island biogeography (SIB) theory . We tested the effects of marine subsidies on species diversity and population density on productive temperate islands, evaluating SIB predictions previously untested at comparable scales and subsidy levels. We found that the diversity of terrestrial breeding bird communities on 91 small islands (approx. 0.0001–3 km 2 ) along the Central Coast of British Columbia, Canada were correlated most strongly with island area, but also with marine subsidies. Species richness increased and population density decreased with island area, but isolation had no measurable influence. Species richness was negatively correlated with marine subsidy, measured as forest-edge soil δ 15 N. Density, however, was higher on islands with higher marine subsidy, and a negative interaction between area and subsidy indicates that this effect is stronger on smaller islands, offering some support for SIB. Our study emphasizes how subsidies from the sea can shape diversity patterns on islands and can even exceed the importance of isolation in determining species richness and densities of terrestrial biota.

1. Introduced insects often incorporate native plants into their diets and might be expected to show a predilection for novel hosts that are phylogenetically related to their normal hosts. The lily leaf beetle, Lilioceris lilii (Coleoptera: Chrysomelidae), is an introduced pest of cultivated lilies. Oviposition behaviour, larval behaviour, and development of L. lilii was examined on a range of potential host plants, as well as on the normal host, Asiatic hybrid lilies Lilium sp.2. Neonate larval feeding behaviour was quantified on 15 food plant species: 10 from the Liliales, three from the Asparagales and two eudicots. Larvae fed plants closely related to the genus Lilium were more likely to initiate feeding, less likely to abandon their food leaf, and consumed more leaf area.3. In no‐choice tests, females oviposited on the novel hosts Lilium philadelphicum, Medeola virginiana, Clintonia borealis, Streptopus amplexifolius, and Polygonatum biflorum; however, all but L. philadelphicum received very few eggs. Non‐Lilium novel hosts were not used for oviposition when presented along with Asiatic lilies in choice tests.4. A single individual was reared to the adult stage on the novel host S. amplexifolius. Several larvae survived to the pupal stage on M. virginiana, although no adults emerged from those pupae. Larvae reared on the native wood lily L. philadelphicum performed equally well or better than on the Asiatic cultivar.5. Our results indicate that the lily leaf beetle poses a threat to native Liliaceae. Several native Lilium species, including L. philadelphicum, are threatened or endangered in certain jurisdictions throughout their range; these species should be monitored closely for colonisation by the beetle.

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Rapid environmental changes in arctic, subarctic and boreal biomes are fuelling the need for effective biodiversity monitoring programs in these regions. Terrestrial arthropods are ideal focal taxa for monitoring, but quantitative comparisons of the efficacy and outcomes of different sampling protocols are limited. Here, the influence of trap type (yellow pan trap or traditional pitfall) and habitat (wet or mesic) on the abundance and diversity of ground‐dwelling arthropods is determined for samples collected in the three northernmost ecoclimatic zones of Canada, using over 32 000 specimens of beetles and spiders. Trap and habitat both influence the abundance, richness, and assemblage composition of arthropods collected, but these effects differ between ecoclimatic zones and depend on taxonomic resolution. Sampling in different habitats yields greater diversity than sampling with different traps in the high arctic, while the inverse is true in the north boreal zone, and neither factor appears to have a significant effect on the diversity of arthropods collected in the subarctic. In all zones, the addition of recessed yellow pan traps to a traditional pitfall trap‐based sampling regime results in the capture of many additional unique species, suggesting that colour is an attractant for at least some ground‐dwelling taxa. These findings have significant implications for large‐scale terrestrial diversity monitoring programs being established or implemented in northern systems. It is recommended that sampling regimes be designed to maximize the diversity of arthropods collected, by including a minimum of two distinct habitats and by using yellow pitfall traps.

Seasonal patterns in the taxonomic and functional structure of epigeic Coleoptera assemblages in wet and mesic habitats were studied in Kugluktuk, Nunavut, Canada. Using pan and pitfall traps, 2638 beetles were collected between 21 June and 13 August 2010. Fifty species (including 17 new territory records) in 11 families were identified. The biomass of each specimen was estimated, and each was assigned to a functional group. Species composition differed between habitats throughout the active season and there was a rapid compositional turnover even though species diversity was similar in both habitats and among sampling periods. The functional beetle assemblages in the two habitats were different, and both assemblages experienced seasonal turnover in function; this effect was more pronounced in the mesic habitats. The beetle fauna in both habitats was predominantly entomophagous. We also examined the influence of seasonal weather patterns on assemblage structure: there is a significant relationship between mean daily temperature and assemblage structure. This relationship indicates that changes in weather (or longer-term changes in climate) could affect the diversity and ecological function of insects in this system. Given the significance of insects in the north, this could result in important changes to northern ecology.

A comparison of methods for assessing age structure and abundance 279-286.