Although invasive plants are a major source of terrestrial ecosystem degradation worldwide, it remains unclear which trophic levels above the base of the food web are most vulnerable to plant invasions. We performed a meta-analysis of 38 independent studies from 32 papers to examine how invasive plants alter major groupings of primary and secondary consumers in three globally distributed ecosystems: wetlands, woodlands and grasslands. Within each ecosystem we examined if green (grazing) food webs are more sensitive to plant invasions compared to brown (detrital) food webs. Invasive plants have strong negative effects on primary consumers (detritivores, bacterivores, fungivores, and/or herbivores) in woodlands and wetlands, which become less abundant in both green and brown food webs in woodlands and green webs in wetlands. Plant invasions increased abundances of secondary consumers (predators and/or parasitoids) only in woodland brown food webs and green webs in wetlands. Effects of invasive plants on grazing and detrital food webs clearly differed between ecosystems. Overall, invasive plants had the most pronounced effects on the trophic structure of wetlands and woodlands, but caused no detectable changes to grassland trophic structure.

Abstract. As the world continues to urbanize, ensuring that urban residents have access to green infrastructure and the ecosystem services it provides will be critical. Furthermore, the distribution of green infrastructure within cities should be equitable so that no socioeconomic group is underserved in terms of the benefits derived from ecosystem services. Our goal was to test whether there were any differences among socioeconomic groups in terms of (1) proximity to open space, (2) proximity to Lake Michigan, (3) tree canopy cover, or (4) bird biodiversity in census tracts across Chicago, IL (USA). These four variables were used as proxies for a number of different ecosystem services. We characterized the first three variables with GIS operations using classified Quickbird imagery and other datasets that describe the urban and natural environment. We used MaxEnt to model suitable bird habitat for 52 species that are regularly observed in the area and combined the habitat maps to estimate bird biodiversity in a spatially explicit manner. Our results suggest that census tracts with more low-to mid-income Hispanic residents were farther away from both open space and Lake Michigan, and had less tree canopy cover and bird biodiversity than other census tracts. Tracts characterized mostly by low-income African Americans were not statistically different in terms of proximity to open space, nor in terms of tree canopy cover or bird biodiversity, than those characterized by higher income residents. Those tracts were, however, significantly farther from Lake Michigan compared to the higher income census tracts. This research suggests the potential for environmental injustice in Chicago and we discuss some possible causes and implications of our findings.

Introduced millipede species in the family Julidae are common in the U.S. but little is known about how they interact with other organisms, such as mites. To start to determine the nature of the relationship, millipedes were sampled from across the eastern U.S.A. and the United Kingdom in [2008][2009]. Sixteen morphospecies of mites (Acari: Astigmata, Mesostigmata) were collected from these millipedes, 12 of which from a total of 13 species of julid millipedes. None of these 12 species was restricted to a single host species. However, 12 of the 16 mite species collected were restricted to either the U.S.A. or the U.K. These results are consistent with locality, rather than host, specificity.

Twospotted spider mite, Tetranychus urticae Koch (Trombidiformes: Tetranychidae), is an important, worldwide pest of watermelon, Citrullus lanatus L. (Thunb.) Matsum. & Nakai (Cucurbitales: Cucurbitaceae). Feeding results in chlorotic spots and leaf necrosis, which can substantially reduce yields. In watermelon, T. urticae is managed solely with acaricides. Issues with acaricide resistance and pesticide label restrictions on number of applications per season require research-based recommendations on products with effective, long-lasting residues. To improve recommendations for T. urticae management in watermelon and to measure possible effects on non-target beneficial mites, we conducted acaricide efficacy trials in two locations in South Carolina, United States. The adulticidal products abamectin, bifenazate, fenpyroximate, and tolfenpyrad and the ovicidal products spiromesifen and etoxazole were tested. We also conducted two bioassays to better determine duration of acaricide residues. In the field trials, all acaricides except tolfenpyrad reduced T. urticae abundance, but all acaricides also reduced abundance of the most common predatory mite, Neoseiulus fallacis (Garman) (Mesostigmata: Phytoseiidae). In the bioassays, abamectin and bifenazate residues caused high adult T. urticae mortality at up to 21 d after treatment, performing better than fenpyroximate and tolfenpyrad. Etoxazole and spiromesifen were longer lasting, with <1 offspring per treated female in the etoxazole treatment at 28 d after treatment. Based on efficacy, abamectin or bifenazate should be rotated with etoxazole for fast knockdown of active stages while reducing reproduction, respectively. However, development and registration of more selective acaricides in watermelon is needed to preserve biological control of T. urticae by predatory mites.

Soil health laws should account for global soil connections