NS Seminar

Date and Location

Apr 26, 2017 - 4:45pm to 5:45pm
Bldg 434, rm 122


Quantitative Tools for Non-Social Scientists in International Development (presented by Devin Cornell, Dept of Sociology)

This project proposes a tool for helping local communities and international development groups interpret large datasets collected as a part of government surveys. The interpretation is intended to help people think through various aspects of problems using data and network analysis/visualization. Although great effort goes into collecting big data via mass surveys, local stakeholders are still not able to take advantage of this data to address problems on the ground. This presentation shows the mathematical basis and results from analysis of stunting (low height-for-age) data in Guatemala using 2012 and 2014 data from USAID.


Below-ground plant–fungus network topology is not congruent with above-ground plant–animal network topology (presented by Taom Sakal, Dept of Ecology, Evolution, and Marine Biology)

Toju, H., Guimarães, P. R., Olesen, J. M., & Thompson, J. N. (2015). Below-ground plant–fungus network topology is not congruent with above-ground plant–animal network topology. Science advances, 1(9), e1500291.

In nature, plants and their pollinating and/or seed-dispersing animals form complex interaction networks. The commonly observed pattern of links between specialists and generalists in these networks has been predicted to promote species coexistence. Plants also build highly species-rich mutualistic networks below ground with root-associated fungi, and the structure of these plant–fungus networks may also affect terrestrial community processes. By compiling high-throughput DNA sequencing data sets of the symbiosis of plants and their root-associated fungi from three localities along a latitudinal gradient, we uncovered the entire network architecture of these interactions under contrasting environmental conditions. Each network included more than 30 plant species and hundreds of mycorrhizal and endophytic fungi belonging to diverse phylogenetic groups. The results were consistent with the notion that processes shaping host-plant specialization of fungal species generate a unique linkage pattern that strongly contrasts with the pattern of above-ground plant–partner networks. Specifically, plant–fungus networks lacked a “nested” architecture, which has been considered to promote species coexistence in plant–partner networks. Rather, the below-ground networks had a conspicuous “antinested” topology. Our findings lead to the working hypothesis that terrestrial plant community dynamics are likely determined by the balance between above-ground and below-ground webs of interspecific interactions. [We will also discuss what nestedness is and how this metric could describe competition and cooperation other fields.]