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Charles Yackulic

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This code was created to run a bioenergetics-based model of movement for Galapagos tortoises. It calculates energetic surplus or deficit at a daily time scale based on inputted temperature (6 times a day) and NDVI value (a single value per days), as well as the mass of an individual. It then uses dynamic programming to determine the optimal timing of movement between two foraging habitats, given time-series of NDVI in each habitat, and temperatures in both habitats and in a transition zone between habitats. The model relies on a variety of empirically derived relationships, including allometric relationships, derived for different groups of organisms (i.e., some relationships are based on analyses across multiples...
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These data represent a set of capture histories of rainbow trout (Oncorhynchus mykiss or RBT) captured in the Colorado River (CR) and(or) detected on the multiplexer array in the Little Colorado River (LCR). Capture trips to the Colorado River occurred in April 2012, July 2012, September 2012, January 2013, April 2013, July 2013, September 2013, January 2014, April 2014, July 2014, and September 2014. Rainbow trout were detected on the PIT array system (MUX) from October 2013 - April 2014.
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The Impacts of Climate Change and Water Supply Management on Fish in the Colorado River
The Colorado River and its major tributaries provide a crucial water supply for more than 40 million people in the American Southwest and in California. This water supply is primarily used in irrigated agriculture but also provides essential drinking water to many large metropolitan areas. Hydropower is also produced at many of the large dams on the river. River flows have declined during the past 15 years due to decreasing watershed runoff associated with a warming climate and ongoing drought. Climate projections indicate a continued decrease in future water availability as runoff continues to decline and temperatures warm. Water-users in the Colorado River basin are concerned about this declining water availability...
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Ambient-shade temperature was measured every 4 h with iButton thermochrons (Maxim Integrated Products, Inc., Sunnyville, CA, USA) placed at 1m above-ground level for a previous paper (Blake et al., 2012 – DOI 10.1111/1365-2656.12020). The Normalized Difference Vegetation Index (NDVI) of the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument (Huete et al. 2002 - http://dx.doi.org/10.1016/S0034-4257(02)00096-2) was used as an index of vegetation quantity. Monthly average NDVI values within the range of each tortoise population were derived based on grid sampling within the convex hull created by upland and lowland relocations of migratory individuals during their sedentary (non-migratory) phases of movement....
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