Here we correct an error in the calculation of the percent change in peak discharges associated with timber harvest and road construction in small, experimentally treated basins by Jones and Grant [1996]. This correction reduces the estimated magnitude of changes, but it does not affect the direction or statistical significance of changes nor our interpretation of mechanisms. References Jones, J. A., and G. E. Grant, Peak flow responses to clear-cutting and roads in small and large basins, western Cascades, Oregon, Water Resour. Res., 32, 959-974, 1996.

We examined the roles of dispersal mechanism, a biological barrier; light availability, an environmental barrier; and level of disturbance, a physical barrier, in explaining the spatial patterns of exotic plant species along road and stream segments in a forest landscape in the western Cascade Range of Oregon (U.S.A). The presence or absence of 21 selected exotic plant species and light levels were observed along 0.3-to 1.0-km transects within four habitat types. Each habitat represented a different level of disturbance: high-use roads, low-use roads, abandoned roads, and streams in the H. J. Andrews Experimental Forest. Nearly 300 50 ϫ 2-m sampling units were surveyed along five transects in each habitat type. We used ordination (nonmetric multidimensional scaling) and logistic regression to analyze data. All of the nearly 200 sampling units along roads with high and low levels of vehicle traffic contained at least one exotic plant species, and some contained as many as 14. Streams that were most recently disturbed by floods 20-30 years ago and abandoned spur roads with no traffic for 20-40 years also had numerous exotic species. Roads and streams apparently serve multiple functions that enhance exotic species invasion in this landscape: they act as corridors or agents for dispersal, provide suitable habitat, and contain reservoirs of propagules for future episodes of invasion. Species-specific dispersal mechanisms, habitat characteristics, and disturbance history each explain some, but not all, of the patterns of exotic species invasion observed in this study.Disponibilidad de Luz y Mechanismos de Dispersión e Invasión de Plantas Exóticas a lo Largo de Caminos y Arroyos en el Bosque Experimental H. J. Andrews, Oregon Resumen: Para explicarnos los patrones espaciales de plantas exóticas a lo largo de segmentos de caminos y de arroyos en un paisaje boscoso del Cascade Range, Oregon, examinamos el papel de los mecanismos de dispersión (una barrera biológica), de la luz (una barrera ambiental) y del nivel de perturbación (una barrera física). Se observaron la presencia o ausencia de 21 especies de plantas exóticas y los niveles lumínicos a lo largo de transectos de 0.3 a 1.0 km en cuatro tipos de hábitat. Cada hábitat presentaba diferentes niveles de perturbación: caminos de uso frecuente, caminos de uso no frecuente, caminos abandonados y arroys en el Bosque Experimental H. J. Andrews. Se trabajó en cerca de 300 unidades de muestreo de 50 ϫ 2 m, a lo largo de cinco transectos en cada tipo de hábitat. Para el análisis de datos utilizamos ordenamiento (escala multidimensional no-numérica) y regresión logística. Las cerca de 200 unidades de muestreo a lo largo de caminos con uso frecuente y no frecuente presentaron por lo menos una especie de planta exótica y algunas presentaron hasta 14. Los arroyas recientemente perturbados por inundaciones (20-30 años) y los caminos abandonados hace 20 -40 años también presentaron numerosas especies exóticas. Aparentemente, los caminos y arroyos realizan varias funciones que acrec...

MotivationThe BioTIME database contains raw data on species identities and abundances in ecological assemblages through time. These data enable users to calculate temporal trends in biodiversity within and amongst assemblages using a broad range of metrics. BioTIME is being developed as a community‐led open‐source database of biodiversity time series. Our goal is to accelerate and facilitate quantitative analysis of temporal patterns of biodiversity in the Anthropocene.Main types of variables includedThe database contains 8,777,413 species abundance records, from assemblages consistently sampled for a minimum of 2 years, which need not necessarily be consecutive. In addition, the database contains metadata relating to sampling methodology and contextual information about each record.Spatial location and grainBioTIME is a global database of 547,161 unique sampling locations spanning the marine, freshwater and terrestrial realms. Grain size varies across datasets from 0.0000000158 km2 (158 cm2) to 100 km2 (1,000,000,000,000 cm2).Time period and grainBioTIME records span from 1874 to 2016. The minimal temporal grain across all datasets in BioTIME is a year.Major taxa and level of measurementBioTIME includes data from 44,440 species across the plant and animal kingdoms, ranging from plants, plankton and terrestrial invertebrates to small and large vertebrates.Software format.csv and .SQL.

Spatial models of under-canopy temperature show that old-growth forests are cooler in spring months than mature forest plantations.

Based on field surveys and analysis of road networks using a geographic information system (GIS), we assessed the hydrologic integration of an extensive logging‐road network with the stream network in two adjacent 62 and 119 km2 basins in the western Cascades of Oregon. Detailed surveys of road drainage for 20 percent of the 350 km road network revealed two hydrologic flow paths that link roads to stream channels: roadside ditches draining to streams (35 percent of the 436 culverts examined), and roadside ditches draining to culverts with gullies incised below their outlets (23 percent of culverts). Gully incision is significantly more likely below culverts on steep (< 40 percent) slopes with longer than average contributing ditch length. Fifty‐seven percent of the surveyed road length is connected to the stream network by these surface flowpaths, increasing drainage density by 21 to 50 percent, depending on which road segments are assumed to be connected to streams. We propose a conceptual model to describe the hydrologic function of roads based on two effects: (1) a volumetric effect, increasing the volume of water available for quickflow and (2) a timing effect, altering flow‐routing efficiency through extensions to the drainage network. This study examines the second of these two effects. Future work must quantify discharge along road segments connected to the stream network in order to more fully explain road impacts on basin hydrology.