Treesearch

Catchment hydrologists have long puzzled over the question: How can catchments rapidly generate storm flows and pulses of solutes in response to storm events? Conceptual models viewing catchments as composed of discrete source areas generating flow at unique time scales and with unique chemical characteristics have been used to explain the observed changes in flow and water chemistry. Surprisingly, those conceptual models usually do not treat the stream channel as one of the potential source areas. Here, we propose the channel-source hypothesis in which the stream itself should be considere...

Context Existing demographic models of California condors have not simultaneously considered individual condor movement paths, the distribution and juxtaposition of release sites, habitat components, or the spatial distribution of threats.Objectives Our objectives were to develop a dynamic spatially explicit and individual-based model (IBM) of California condor demography and to evaluate its ability to replicate empirical data on demography and distribution from California (1995–2019).Methods We built a female-only spatially explicit California condor IBM in HexSim, using a daily timestep...

Background: While benefits of greenness to health have been reported, findings specific to child respiratory health are inconsistent.Methods: We utilized a prospective birth cohort followed from birth to age 7 years (n = 617). Residential surrounding greenness was quantified via Normalized Difference Vegetation Index (NDVI) within 200, 400, and 800 m distances from geocoded home addresses at birth, age 7 years, and across childhood. Respiratory health outcomes were assessed at age 7 years, including asthma and lung function [percent predicted forced expiratory volume in the first second...

This study aimed to assess pesticide exposure and its determinants in children aged 5–14 years. Urine samples (n = 953) were collected from 501 participating children living in urban areas (participant n = 300), rural areas but not on a farm (n = 76), and living on a farm (n = 125). The majority provided two samples, one in the high and one in the low spraying season. Information on diet, lifestyle, and demographic factors was collected by questionnaire. Urine was analysed for 20 pesticide biomarkers by GC–MS/MS and LC-MS/MS. Nine analytes were detected in > 80% of samples, including six...

A combination of natural (tropical latitudes) and human induced (Climate Change, Urban heat island) conditions give rise and exacerbate extreme hot temperatures, but mechanisms are unclear. Land use and land cover change (LULC) is considered one of the main causes of Urban Heat Island (UHI) but its contribution varies depending on local conditions. This study focuses on determining the influence of land use change on the UHI effect in Tuxtla Gutiérrez City by investigating the relationship between LULC and land surface temperature (LST). Through Landsat 5 and Landsat 8 imagery, this study...

Determining the genetic consequences of both historical and contemporary events can clarify the effects of the environment on population connectivity and inform conservation decisions. Historical events (like glaciations) and contemporary factors (like logging) can disrupt gene flow between populations. This is especially true among species with specialized ecological requirements and low dispersal ability, like amphibians. We test for the genetic consequences of historical and contemporary disturbances in the coastal giant salamander (Dicamptodon tenebrosus) in the Pacific Northwest of...

Food web analyses offer useful insights into understanding how species interactions, trophic relationships, and energy flow underpin important demographic parameters of fish populations such as survival, growth, and reproduction. However, the vast amount of food web literature and the diversity of approaches can be a deterrent to fisheries practitioners engaged in on-the-ground research, monitoring, or restoration. Incorporation of food web perspectives into contemporary fisheries management and conservation is especially rare in riverine systems, where approaches often focus more on the...

Staff on the Entiat Ranger District of the Okanogan-Wenatchee National Forest in Washington state partnered with researchers to develop a strategy to improve the sustainability of the district’s recreation program. The need to pursue a sustainable recreation strategy came about in response to a series of severe wildfires that damaged recreation infrastructure and altered natural resource conditions. Concurrent to those wildfires was continued limited funding for infrastructure maintenance and recreation management. Researchers worked with Entiat Ranger District staff to develop and...

Climate change can act to facilitate or inhibit invasions of non-native species. Here, we address the influence of climate change on control of non-native common carp (hereafter, carp), a species recognized as one of the “world’s worst” invaders across the globe. Control of this species is exceedingly difficult, as it exhibits rapid population growth and compensatory density dependence. In many locations where carp have invaded, however, climate change is altering hydrologic regimes and may influence population demography and efficacy of human control efforts. To further evaluate these...

We document the response of a 2 day wildfire smoke event on a moist temperate coniferous old-growth forest in the western U.S. Wildfire smoke increased air temperature and suppressed relative humidity and total incoming radiation. Despite these conditions a ∼10% increase in ecosystem photosynthesis was observed. This was explained by a large increase (41%) in ecosystem-scale stomatal conductance, inferred from measurements of carbonyl sulfide. Increased stomatal conductance contradicts expected stomatal closure at high vapor pressure deficit and was likely caused by an increase in diffuse...