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Full-Text Articles in Life Sciences

Modeling Vegetation Cover At Mount St Helens Using Highly Correlated Vegetation Indices, Sara Livingston Nov 2022

Modeling Vegetation Cover At Mount St Helens Using Highly Correlated Vegetation Indices, Sara Livingston

Geography and the Environment: Graduate Student Capstones

The eruption of Mount St. Helens in 1980 devastated the landscape and obliterated all ground vegetation within a 620 km2 blast zone radius. The destructive forces of the lateral blast, debris avalanche, tephra plume, and lahar flow created a complex mosaic of disturbance zones, that subsequently yielded various rates of landscape recovery. Remote sensing is an efficient method for monitoring landscape-scale changes by recording the distinct spectral reflectance of vegetation. Based on statistically significant correlations between Vegetation Indices and vegetation parameters, an empirical model can be developed for vegetation cover predictions. This capstone analysis found that NDVI holds the strongest …


Responses Of Arthropods To Fire And How Pollinators And Pollination Services Are Affected By Fire Severity, Blyssalyn V. Bieber Jan 2022

Responses Of Arthropods To Fire And How Pollinators And Pollination Services Are Affected By Fire Severity, Blyssalyn V. Bieber

Electronic Theses and Dissertations

Fires impact ecosystems globally and due to climate change, there are shifts in fire regimes that impact ecological communities which provide essential ecosystem services. Focusing on arthropods, fire can influence this ubiquitous animal group in various way. We performed a comprehensive meta-analysis evaluating how fires impact differing arthropod functional groups. We found that overall, fire negatively effects community level responses for most functional groups with herbivores as the only exception showing some positive effects of fire. We also studied mixed-severity fires that burned >20 years ago and compared floral visitor communities across fire severities. We implemented a pollinator exclusion experiment …


Environmental Gradients Impact Key Leaf Traits In Riparian Trees, Amanda Malone Jan 2022

Environmental Gradients Impact Key Leaf Traits In Riparian Trees, Amanda Malone

Electronic Theses and Dissertations

Specific leaf area (SLA) reflects a plant’s carbon investment per area and relates to generalized leaf economics spectrum growth strategies (LES). To fill gaps of knowledge about intraspecific SLA variation and why it is often inconsistent with the LES, we studied the response of two riparian tree species along the urban-rural gradient in Northeastern Colorado: an invasive, nitrogen-fixer with broad tolerances and a nitrogen-limited and shade-intolerant native. Despite these differences, the two species responded similarly, apart from the response to the urban-rural gradient, in which lower nitrogen in rural areas was associated with a more conservative strategy in the native …


Poor Acclimation To Experimental Field Drought In Subalpine Forest Tree Seedlings, Alex Goke, Patrick H. Martin Jan 2022

Poor Acclimation To Experimental Field Drought In Subalpine Forest Tree Seedlings, Alex Goke, Patrick H. Martin

Biological Sciences: Faculty Scholarship

The ability of tree species to acclimate and tolerate projected increases in drought frequency and intensity has fundamental implications for future forest dynamics with climate change. Inquiries to date on the drought tolerance capacities of tree species, however, have focused almost exclusively on mature trees with scant in situ work on seedlings, despite the central role that regeneration dynamics play in forest responses to changing conditions. We subjected naturally established seedlings of co-dominant subalpine conifer species (Abies lasiocarpa and Picea engelmannii) in the southern Rocky Mountains to 2 years of in situ summer precipitation exclusion, simulating summer drought …