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Invasive grass removal with herbicide is an important component of the restoration process in many prairie and grassland ecosystems. Management of invasive grasses in areas with high concentrations of native plants necessitates investigation of off-target herbicide effects on sensitive native species. Two graminoid-specific herbicides, Fusilade (active ingredient fluazifop-P-butyl) and Envoy Plus (active ingredient clethodim), are frequently used to control invading broadleaf pasture grasses in Pacific Northwest prairies with little knowledge of how these chemicals impact native plants. One such native plant, common camas (Camassia quamash), is a characteristic forb of these prairies that often grows in areas treated with these herbicides. Because camas is a critical resource for native pollinators and holds ethnoecological significance to native peoples, it is important that management methods do not negatively impact this plant. The objective of this study was to understand if and how various seasonal applications of clethodim and fluazifop may impact camas. We implemented a factorial design testing the effects of herbicide type (fluazifop, clethodim, control) and application season-frequency (combinations of mid-spring, late-spring, fall) on camas growth, foliar cover, reproduction, and palatability to herbivores. Our results show that herbicide treatments may reduce leaf length and increase flower and seed production, but do not influence seed viability or palatability to herbivores. The observed effects are not likely to be ecologically detrimental, suggesting that repeat applications of either fluazifop or clethodim can be safely used in areas with high concentrations of this iconic prairie species.
Fire exclusion has contributed to substantial basal accumulations of forest floor fuels in many historically fire-prone forests in western North America. These accumulations can contribute to undesired impacts (e.g., elevated tree mortality, more smoke production). Thus, managers interested in limiting some of these impacts require a better understanding of the spatial factors contributing to forest floor fuel variation in long-unburned forests. To address this need, we measured the forest floor mound size and depth of each layer at four distances from the tree (base, half, edge, and beyond) in each cardinal direction from the tree, and a subset of density measures for each layer and position around 25 large sugar pine (Pinus lambertiana) in the Klamath Mountains of California. Based on our study we found: 1) duff depths were greater than litter depths and both decreased with distance from tree; 2) duff densities were typically greater than litter but were highly variable with distance to tree; 3) litter and duff depths were positively correlated with loading; 4) use of a previously developed depth-to-loading equation performed well, but tended to underestimate litter loading and overestimate duff loading; and 5) tree size was the most strongly related to basal accumulations of forest floor fuels. Our results indicate there are consistent tree characteristics that can help predict the accumulation of forest floor fuels. This research can help provide managers with site-specific equations to inform fuel and fire treatments in areas with substantial basal accumulation in forests with large sugar pine.
The dynamic nature of large rivers is often diminished by anthropogenic alterations resulting in simplified stream networks with decreased floodplain connectivity and ecological function which adversely impact native organisms. However, little is known about the importance of large river floodplains to fish communities in the Pacific Northwest, especially during winter high flows. Our objectives were to document seasonal use of a Willamette River floodplain for native and non-native fish by measuring: 1) fish community characteristics (species richness, native versus non-native status, relative abundance), 2) spawning and rearing, 3) timing of use and movement, and 4) use by federally protected juvenile spring Chinook salmon (Oncorhynchus tshawytscha). During fall 2011 through spring 2012, a floodplain was sampled with a backpack electrofisher and out-migrant trap. A total of 12 native and 11 non-native species were detected. During nine electrofishing samples, 691 fish were collected, of which 95% were native. An estimated 42,297 fish were captured by the out-migrant trap; 98% of which were native and most were age-0 threespine stickleback (Gasterosteus aculeatus). Native species were detected on the floodplain prior to non-native species and tended to emigrate from the floodplain before non-native species, leading to a higher potential of stranding for non-native species as waters recedes. This study documents use of floodplain habitat by native and non-native fish species for seasonal flood refuge, rearing and spawning. Our results demonstrate native fish communities could potentially benefit from conservation of existing floodplains and restoration of floodplains changed by land use practices and altered flow regimes.
Timber cruise data can provide useful information not available elsewhere. Measurements of timber volume (timber cruises) from the early 20th century for Coos County, Oregon, were used to assess the degree to which tree species distribution and timber volume varied with edaphic and climatic factors. The study area has diverse geology in a moderate maritime climate, and represents an area of forest transition between the Coast Range and the Klamath Mountains. Species distribution was determined from 629 cruised 1-mi2 (2.59 km2) sections, and timber volume from 252 sections of old-growth forest. Most forests were dominated by Douglas-fir (Pseudotsuga menziesii); Sitka spruce (Picea sitchensis), although least frequent, had the second-most timber volume. All six commercial conifer species differed substantially in distribution in relation to geography and to environment. Both distribution and volume of grand fir (Abies grandis) varied with geologic unit and general soil type: Sitka spruce, with soil and maximal summer temperature (–sign); Douglas-fir, with temperature ( ) and summer precipitation ( ); western hemlock (Tsuga heterophylla), with precipitation ( ); Port-Orford-cedar (Chamaecyparis lawsoniana), with precipitation (–); and western redcedar (Thuja plicata), with no factor. Importance of Douglas-fir and hemlock increased on geologic units with sediments from inland plutonic sources, which reduced importance of Port-Orford-cedar. Some species varied significantly among soil units within a geological formation, and vice-versa. When choosing which species to plant, these cruise data can supplement or replace guidelines based on plant associations.
Overland movement of recreational boaters between waterbodies is a significant pathway for spreading aquatic invasive species (AIS). Boater awareness of AIS and proper boat cleaning procedures may prove beneficial in reducing the transport, introduction, and establishment of invaders. Our objectives were to observe the use and determine the efficacy of a public boat wash station, gain a better understanding of boater knowledge on AIS and boat cleaning procedures, and help guide future educational outreach and AIS management. We conducted a three-tier human subjects survey at Tenmile Lake, Oregon over a two-year period in which a boat wash station was installed, allowing comparison of boater behavior and attitudes before and after the station was operational. The survey consisted of an observational survey, a short form (quick answer) survey, and an in-depth survey in which boaters could elaborate on their knowledge of AIS and regulations. The comparison between boaters surveyed before and after the installation of a boat wash station indicated discrepancies between what boaters say they will do and how they behave. While 76% of boaters said they would use a boat wash station prior to its installation, only 39% of boaters were observed using the station after it was installed. Additionally, the surveys identified knowledge gaps of boater AIS awareness, with > 20% of boaters unable to name any AIS. Our research indicates that even with innovative tools and targeted outreach, knowledge of AIS is still limited among the boating community and other education and management techniques need exploration.
A native population of arctic grayling (Thymallus arcticus) exists in the upper Missouri River drainage of Montana. While formerly abundant, agricultural practices, predation, angling pressure, barriers to mobility, and competition from other species appear to be the causes of decreased presence of artic grayling in the Northwest (Skaar 1989). The purpose of this study was to augment the information base of the swimming ability of arctic grayling and to examine the effect of repeated trials using the same fish. Forty hatchery-raised grayling were separated into two cohorts and reared in an artificial stream. The mean fork length of all fish was 290 mm (SD ± 16). Cohort 1 was tested in a swim chamber experiment once per week for three consecutive weeks. Cohort 2 was tested only once in the swim chamber sixteen weeks later. Each fish was tested by placing it in the chamber initially operating at a low water velocity (30.5 cm s-1) and then regularly increasing the velocity until the fish rested on the screen at the downstream end of the chamber. The maximum water velocity against which each fish held its position was observed, and is reported as the sprint speed (Usprint). Overall the mean Usprint observed was 5.64 BL (body length) s-1 (SD ± 0.78) equal to an absolute velocity of 1.66 m s-1 (SD ± 0.19). Cohort 1 had a mean Usprint of 5.40 BL s-1 (1.62 m s-1) and Cohort 2 had a mean Usprint of 6.33 BL s-1 (1.77 m s-1). There were significant differences, and a generally increasing trend, in Usprint between the successive trials using Cohort 1.
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