Large herbivore migrations are imperiled globally; however the factors limiting a population acro... more Large herbivore migrations are imperiled globally; however the factors limiting a population across its migratory range are typically poorly understood. Zambia's Greater Liuwa Ecosystem (GLE) contains one of the largest remaining blue wildebeest (Connochaetes taurinus taurinus) migrations, yet the population structure, vital rates, and limiting factors are virtually unknown. We conducted a long‐term demographic study of GLE wildebeest from 2012 to 2019 of 107 collared adult females and their calves, 7352 herd observations, 12 aerial population surveys, and concurrent carnivore studies. We applied methods of vital rate estimation and survival analysis within a Bayesian estimation framework. From herd composition observations, we estimated rates of fecundity, first‐year survival, and recruitment as 68%, 56%, and 38% respectively, with pronounced interannual variation. Similar rates were estimated from calf‐detections with collared cows. Adult survival rates declined steadily from ...
Viability criteria are ecological and biological conditions that are measurable and that must be ... more Viability criteria are ecological and biological conditions that are measurable and that must be met for steelhead to be considered at low risk of extinction. The scientific literature on this topic indicates that predicting the conditions for viability is inherently uncertain due to the ...
The hydro-ecological modeling group at CSUMB is attempting to predict these effects, using comput... more The hydro-ecological modeling group at CSUMB is attempting to predict these effects, using computer models so that the future impacts of land use change on water resources can be known in advance. This will lead to better-informed planning, and a community that is ...
Woodchip bioreactors are capable of removing nitrate from agricultural runoff and subsurface tile... more Woodchip bioreactors are capable of removing nitrate from agricultural runoff and subsurface tile drain water, alleviating human health hazards and harmful discharge to the environment. Water pumped from agricultural tile drain sumps to nearby ditches or channels could be cost effectively diverted through a woodchip bioreactor to remove nitrate prior to discharge into local waterways. Sizing the bioreactor to achieve targeted outlet concentrations within a minimum footprint is important to minimizing cost. Determining the necessary bioreactor size should involve a hydrological component as well as reaction type and rates. We measured inflow and outflow nitrate concentrations in a pumped open-channel woodchip bioreactor over a 13-month period and used a tanks-in-series approach to model hydrology and estimate parameter values for reaction kinetics. Both zero-order and first-order reaction kinetics incorporating the Arrhenius equation for temperature dependence were modeled. The zero-...
Large herbivore migrations are imperiled globally; however the factors limiting a population acro... more Large herbivore migrations are imperiled globally; however the factors limiting a population across its migratory range are typically poorly understood. Zambia's Greater Liuwa Ecosystem (GLE) contains one of the largest remaining blue wildebeest (Connochaetes taurinus taurinus) migrations, yet the population structure, vital rates, and limiting factors are virtually unknown. We conducted a long‐term demographic study of GLE wildebeest from 2012 to 2019 of 107 collared adult females and their calves, 7352 herd observations, 12 aerial population surveys, and concurrent carnivore studies. We applied methods of vital rate estimation and survival analysis within a Bayesian estimation framework. From herd composition observations, we estimated rates of fecundity, first‐year survival, and recruitment as 68%, 56%, and 38% respectively, with pronounced interannual variation. Similar rates were estimated from calf‐detections with collared cows. Adult survival rates declined steadily from ...
Viability criteria are ecological and biological conditions that are measurable and that must be ... more Viability criteria are ecological and biological conditions that are measurable and that must be met for steelhead to be considered at low risk of extinction. The scientific literature on this topic indicates that predicting the conditions for viability is inherently uncertain due to the ...
The hydro-ecological modeling group at CSUMB is attempting to predict these effects, using comput... more The hydro-ecological modeling group at CSUMB is attempting to predict these effects, using computer models so that the future impacts of land use change on water resources can be known in advance. This will lead to better-informed planning, and a community that is ...
Woodchip bioreactors are capable of removing nitrate from agricultural runoff and subsurface tile... more Woodchip bioreactors are capable of removing nitrate from agricultural runoff and subsurface tile drain water, alleviating human health hazards and harmful discharge to the environment. Water pumped from agricultural tile drain sumps to nearby ditches or channels could be cost effectively diverted through a woodchip bioreactor to remove nitrate prior to discharge into local waterways. Sizing the bioreactor to achieve targeted outlet concentrations within a minimum footprint is important to minimizing cost. Determining the necessary bioreactor size should involve a hydrological component as well as reaction type and rates. We measured inflow and outflow nitrate concentrations in a pumped open-channel woodchip bioreactor over a 13-month period and used a tanks-in-series approach to model hydrology and estimate parameter values for reaction kinetics. Both zero-order and first-order reaction kinetics incorporating the Arrhenius equation for temperature dependence were modeled. The zero-...
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Papers by Fred Watson