Flash talks 1

Location, location, location: The Kansas High Plains Aquifer

Ethan
Addicott
Knob
10:30am
Location, location, location: The Kansas High Plains Aquifer (KHPA) supports the congressional district with the highest market value for agriculture in the nation. We find that economic jurisdiction plays a significant role in the value of groundwater and within state variation in groundwater value can be as large as across state variation. Taking the statewide estimation of changes in the value of groundwater in the KHPA by Fenichel et al. (2016), we repeat the approach within each of the five groundwater management districts over the KHPA. Considering each district separately better reflects spatial variation in the aquifer and the current management practices within districts, and limits arbitrage among water districts. Differences in district-wide accounting prices for groundwater create opportunities for arbitrage. As the accounting price is dictated by scarcity, a statewide approach may undervalue the resource. This implies that the average price of an acre foot of groundwater with district pricing should be greater than or equal to the statewide price of an acre foot of water. A district level approach to groundwater valuation recognizes that water transfers across districts may involve nontrivial transaction costs. This is especially pertinent as municipalities and districts seek state permission to transfer large quantities of groundwater to meet agricultural and municipal needs.

The Maasai Steppe of northern Tanzania supports a lucrative tourism

Mary
Burak
Knob
10:30am
The Maasai Steppe of northern Tanzania supports a lucrative tourism industry. But one species particularly charismatic to tourists - the African lion - is embroiled in human conflict. Increasing land use change by the Maasai tribe has heightened lion attacks on livestock. This inflicts both a cultural and economic loss on the Maasai, prompting them to retaliate by killing lions. Conservation initiatives seek to mediate this human-wildlife conflict but overlook how land development may threaten lion genetic connectivity - without which the longevity of lions is not guaranteed. My doctoral work will use techniques from landscape genetics, a new and burgeoning field, to evaluate the effect of anthropogenic activity on lion genetic connectivity. The objective of my doctoral work will be to map possible land management scenarios that foster human-lion coexistence. This will be done by assessing spatial trends of human land use, strengths and weaknesses of lion connectivity, as well as human tolerance of lions.

Grazing halos'barren areas of sand that surround coral patch reefs

Bart
DiFiore
Knob
10:30am
Grazing halos'barren areas of sand that surround coral patch reefs in otherwise continuous seagrass plains'form due to predator avoidance by herbivorous fish and echinoderms that preferentially graze seagrasses close to the safety of the reef structure. Grazing halos are readily visible from satellite imagery and halo size may be indicative of local predator abundance. This study analyzed grazing halos in the South Water Caye Marine Reserve (Belize) and the Florida Keys National Marine Sanctuary (U.S.A) using remote sensing techniques and field surveys. Twenty-one patch reefs were analyzed in both no take conservation zones and paired sites. At each patch reef herbivore behavior was determined using grazing assays deployed along transects from the reef edge. Fish abundance and reef rugosity were quantified at each patch. Mixed linear effects models were used to determine relationships between grazing and fish community structure with distance when controlling for substrate type and reef complexity. Grazing was found to differ as a function of predator size and herbivore abundance across all patches, and between no take protected sites and fished sites in the Florida Keys.

Understanding the processes that regulate the carbon and nitrogen cycles

Julia
Monk
Knob
10:30am
Understanding the processes that regulate the carbon and nitrogen cycles is an essential step in forecasting the effects of climate change. Some of these processes are driven by living organisms, and most research on this biotic component of nutrient cycling has focused on plants and microbes, as these abundant organisms sequester atmospheric carbon. However, theoretical studies have shown that animals may also play an important role in nutrient cycling: in fact, the amount of carbon sequestered or released through animal-mediated processes could be comparable to the CO2 emissions of large industrial nations. The role of animals in facilitating carbon and nutrient cycling may be especially important in nutrient-poor ecosystems with barren vegetation, such as the high-altitude dry steppe of San Guillermo National Park in the Argentine Andes. My research investigates how the activity of pumas, vicu'as, and scavengers impacts carbon and nutrient cycling in San Guillermo. Specifically, I will be studying the effects of carcass deposition (predation) on soil nutrients, and testing whether scavenger activity mediates the flow of nutrients from carcasses to soil. I will also assess the indirect effects of predation on nutrient cycling, investigating how predation risk may influence herbivore movement and territoriality and how these behavioral patterns could be driving the flow of nutrients from hotspots to low productivity sites. Results from this study should inform our understanding of the biotic processes that drive carbon and nutrient cycling in this arid region, illuminating the potential cascading effects of animal species loss on primary productivity and climate change.

This coastal protection study balances the cost of building coastal walls

Lun
Ou
Knob
10:30am
This coastal protection study balances the cost of building coastal walls against the benefits of reduced expected storm damage. We first calculate the probability of storm flooding using an extreme value function based on tidal data. We then calculate the flooding damage at each property in the area given the flood height of each potential storm and the property elevation. This leads to a probability distribution of aggregate storm damage. The analysis suggests that the optimal strategy for the studied community is to build a five-foot reinforced wall along the coast to eliminate the damage from all but very rare and harmful storms.

In field studies of the population ecology, knowing where fruits and seeds

Anna
Sugiyama
Knob
10:30am
In field studies of the population ecology, knowing where fruits and seeds are being produced is often required. In dioecious species, production of fruits/seeds and pollen is spatially separated and knowing the sex of individual plants is not always feasible when some reproductive individuals are not flowering or fruiting. Identifying the sex of individuals thus requires long-term phenology data on an individual basis but this is rarely available. In this study, we tested the feasibility of using the potential difference in pollen concentration in soil underneath the crowns of individual plants to identify the sex of plant overhead in a dioecious species. We hypothesized that the pollen concentration in soil beneath male plants would be significantly higher than beneath female plants because only males produce pollen and pollen deposition should accumulate in the soil underneath the male plants over time. We collected samples from surface soil under both sexes of an insect-pollinated dioecious shrub, Aucuba japonica (Garryaceae). Pollen grains were present in surface soil in both Oe and A horizons, and pollen concentration under males was significantly higher than under females. Pollen concentrations beneath males were positively correlated with male plant height, potentially reflecting greater pollen production by larger individuals. Considering the small plant size and relatively low pollen production of A. japonica, the method may hold promise for studying other species, especially in the tropics. Knowing the sex of individuals may be facilitated by our time-insensitive, relatively low-cost method using soil pollen beneath individual plants.