4/1/2023 0 Comments Imagej download for mac![]() The results of this research have been used to develop a suite of recommended best practices that can be implemented at the outset of a wetland mitigation project to reduce the risk of invasion. Our analysis revealed species-specific environmental drivers of invasion with a few factors consistently important across all targeted invaders – notably, canopy cover (light availability), hydrology, and a handful of important physiochemical variables. (cattail), three invasive species that are known to be problematic on wetland mitigation sites in the region. We targeted Arthraxon hispidus (joint-head grass), Microstegium vimineum (Japanese stiltgrass), and Typha spp. Data analysis involved a multi-metric statistical approach combining correlation, AIC, and CCA to arrive at a plausible model for invasion risk by species based on environmental correlates. We sampled vegetation and environmental variables (site hydrology, light availability, soil physiochemistry, site age) across invasion gradients at multiple wetland mitigation sites in the Coastal Plain and Piedmont physiographic provinces of Virginia. The purpose of this study was to characterize important environmental drivers of plant invasions on wetland mitigation sites. Invasive plant species can alter natural communities and degrade ecosystem function, yet the factors influencing species invasion are poorly understood. Experimental approaches or large-scale manipulative studies may be necessary to isolate the effects of ALAN on streams and fish in urban contexts. Our results imply that the relatively low-levels of ALAN observed in canopied streams may exert only subtle effects on small stream fish assemblages, which are difficult to detect amongst the multiple, confounded stressors impacting these relatively species-poor, urban systems. Species richness scaled negatively with total phosphorus and α-diversity scaled negatively with orthophosphate. Nutrient concentrations were negatively related to mean fish mass and fish assemblage diversity. Species richness and α-diversity (Hill numbers) scaled positively with mean stream depth. There were no differences in fish assemblages (i.e., abundance, relative abundance, biomass, diversity, guild composition) between lit and unlit reaches (> 100 m apart). Our results show that light trespass into urban streams is approximately doubled during leaf-off in winter months (1.97 lux ± 0.28) compared to leaf-on in summer months (1.00 lux ± 0.19), highlighting the important interceptive effect of canopy coverage in headwater systems. We investigated the effects of ALAN on fish assemblages in 20 lit-unlit paired stream reaches across 10 sites in Columbus, Ohio, USA across two years. Global site factor from SSP HP are highly correlated with traditional methods (R2 >0.9), while leaf area indexĮstimates are lower, especially in more closed canopies where traditional methods fail to capture fine gaps.Īrtificial light at night (ALAN) is pervasive in urban environments, yet its potential effects on biotic communities of urban streams are not fully understood. Sharper images of higher resolution, resulting in more definition of fine canopy structure. The SSP HP method leverages built-in features of current generation smartphones to produce I compared hemispherical photosĬaptured with a digital single lens reflex camera and 180◦ lens to those extracted from smartphone spherical ![]() Spherical panoramas produced by many smartphone camera applications. As an alternative, hemispherical images can be extracted from However, traditional HP methods requireĮxpensive equipment, are sensitive to exposure settings, and produce limited resolution which dramaticallyĪffects the accuracy of gap fraction estimates. Photography (HP) is a popular tool to estimate canopy attributes. Accurate estimates of forest canopy structure are central for a wide range of ecological studies.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |