Gardening for Wildlife: Tree canopy and small-scale planting influences on arthropod and bird abundance

Do urban gardens restored with native shrubs contribute towards conservation of birds? Portland, Oregon, is a mid-sized city with many restored yard habitats and nearby regional natural areas, with yards varying in the degree of native plantings and the sizes and groupings of the yards involved. We studied several of the purported ecological benefits attributed to these widespread, but small-scale, urban gardens. We measured the relative success of yard habitats in contributing to diversity and abundance of forest-habitat birds. We studied how the abundance and diversity of shrubs, arthropods, and birds were related. We compared two neighborhoods; one having high, native tree cover, and the second having lower, non-native tree cover. Both neighborhoods had nearby greenspaces. We selected 6 replicate yards in each neighborhood, each with at least a minimum number of native shrubs. We also measured bird species richness using citizen science data. The abundance of arthropods significantly predicted the bird species richness. Both the amount of regional and local tree cover had a stronger statistical signal than shrub cover. The presence of native species of shrubs in these yards was not a good predictor for abundance of arthropods

Digital record of specimens, including voucher material, from the study of a pollinator habitat restoration site under a commercial solar array in Jackson County, Oregon, 2019

Photovoltaic solar energy installation is booming, frequently near agricultural lands. Traditionally, the land underneath ground-mounted photovoltaic panels is unused, though some are repurposing it as habitat for pollinating insects. However, the impact of the solar panel canopy on the pollinator-plant community understory is unknown. In this study (Graham et al., 2020), we investigated the effects of solar arrays on plant composition, bloom timing and foraging behavior of pollinators in open fields (control), and in full shade and partial shade areas under solar panels in a predominant agricultural region of southern Oregon. Pollinating insect specimens were collected using hand nets, and identified to the lowest taxonomic group possible by M. Graham, A.R. Moldenke, and L.R. Best. A total of 85 voucher specimens were deposited into the Oregon State Arthropod Collection; accession record: OSAC_AC_2021_03_11_001-01

Taxonomic voucher specimens for study of post-wildfire forest habitat in Douglas County, Oregon

this publication provides data about voucher specimens deposited in the museum in conjunction with a research project on pollinators

Taxonomic voucher specimens for study of bee communities in intensively managed Douglas-fir forests in the Oregon Coast Range

Understanding how pollinators respond to anthropogenic land use is key to conservation of biodiversity and ecosystem services, but few studies have addressed this topic in coniferous forests, particularly those managed intensively for wood production. This study reports on voucher material generated as part of Zitomer et al. (2023), that assessed changes in wild bee communities with time since harvest in 60 intensively managed Douglas-fir (Pseudotsuga menziesii) stands in the Oregon Coast Range across a gradient in stand age spanning a typical harvest rotation (0-37 years post-harvest). We additionally assessed relationships of bee diversity and community composition to relevant habitat features, including availability of floral resources and nest sites, understory vegetation characteristics, and composition of the surrounding landscape. Specimens were collected using a combination of passive sampling methods-blue vane traps and white, blue, and yellow bowl traps- and hand-netting and were identified to the lowest possible taxonomic level by A.R. Moldenke and L.R. Best. Four hundred and ten taxonomic voucher specimens were deposited into the Oregon State Arthropod Collection (Accession# OSAC_AC_2023_01_09-001-01) to serve as a reference for future research

Wild bee diversity is enhanced by experimental removal of timber harvest residue within intensively managed conifer forest

The use of timber harvest residue as an energy source is thought to have environmental benefits relative to food-based crops, yet the ecological impact of this practice remains largely unknown. We assessed whether the abundance and diversity of wild bees (Apoidea) were influenced by the removal of harvest residue and associated soil compaction within managed conifer forest in western Oregon, USA. We sampled bees over two years (2014-2015) on study plots that were subjected to five treatments representing gradients in removal of harvest residue and soil compaction. We collected >7,500 bee specimens from 92 distinct species/morphospecies that represented five of the seven bee families. We trapped 3x more individuals in the second year of the study despite identical sampling effort in both years, with most trapped bees classified as ground-nesting species. Members of the sweat bee family (Halictidae) comprised more than half of all specimens, and the most abundant genus was composed of metallic green bees (Agapostemon, 33.6%), followed by long-horned bees (Melissodes, 16.5%), sweat bees (Halictus, 15.9%), and bumble bees (Bombus, 13.6%). In both years, abundance and observed species richness were greatest in the most intensive harvest residue treatment, with other treatments having similar values for both measures. Our study indicates that early successional managed conifer forest that has experienced removal of harvest residue can harbor a surprising diversity of wild bees, which are likely to have important contributions to the broader ecological community through the pollination services they provide

Abiotic and Biotic Soil Characteristics in Old Growth Forests and Thinned or Unthinned Mature Stands in Three Regions of Oregon

We compared forest floor depth, soil organic matter, soil moisture, anaerobic mineralizable nitrogen (a measure of microbial biomass), denitrification potential, and soil/litter arthropod communities among old growth, unthinned mature stands, and thinned mature stands at nine sites (each with all three stand types) distributed among three regions of Oregon. Mineral soil measurements were restricted to the top 10 cm. Data were analyzed with both multivariate and univariate analyses of variance. Multivariate analyses were conducted with and without soil mesofauna or forest floor mesofauna, as data for those taxa were not collected on some sites. In multivariate analysis with soil mesofauna, the model giving the strongest separation among stand types (P = 0.019) included abundance and richness of soil mesofauna and anaerobic mineralizable nitrogen. The best model with forest floor mesofauna (P = 0.010) included anaerobic mineralizable nitrogen, soil moisture content, and richness of forest floor mesofauna. Old growth had the highest mean values for all variables, and in both models differed significantly from mature stands, while the latter did not differ. Old growth also averaged higher percent soil organic matter, and analysis including that variable was significant but not as strong as without it. Results of the multivariate analyses were mostly supported by univariate analyses, but there were some differences. In univariate analysis, the difference in percent soil organic matter between old growth and thinned mature was due to a single site in which the old growth had exceptionally high soil organic matter; without that site, percent soil organic matter did not differ between old growth and thinned mature, and a multivariate model containing soil organic matter was not statistically significant. In univariate analyses soil mesofauna had to be compared nonparametrically (because of heavy left-tails) and differed only in the Siskiyou Mountains, where they were most abundant and species rich in old growth forests. Species richness of mineral soil mesofauna correlated significantly (+) with percent soil organic matter and soil moisture, while richness of forest floor mesofauna correlated (+) with depth of the forest floor. Composition of forest floor and soil mesofauna suggest the two groups represent a single community. Soil moisture correlated highly with percent soil organic matter, with no evidence for drying in sites that were sampled relatively late in the summer drought, suggesting losses of surface soil moisture were at least partially replaced by hydraulic lift (which has been demonstrated in other forests of the region)

Authentic Field Ecology Experiences for Teachers

This paper will focus on one teacher field research experience situated in the Pacific Northwes

Pollination ecology within the Sierra Nevada

Volume: 42Start Page: 223End Page: 28