Gregory R. Houseman, PhD

Gregory R. Houseman, PhD

Assistant Professor of Biology

Office: 519 Hubbard Hall

Phone: (316) 978-5841

Email: greg.houseman@wichita.edu

Education Degree Year Field of Study

Michigan State University PhD 2004 Plant Biology / EEBB

Illinois State University MS 1998 Biology

AuSable Institute 1992 Naturalist Certificate

Cornerstone University BA 1990 Biology

Professional Experience

Research Interests

External Research Grants

Peer-Reviewed Publications

Courses Taught

Professional Experience 2008-present. Assistant Professor, Wichita State University

2006-2008. Post-doctoral Fellow, University of Kansas

2004-2006. Research Associate, Kellogg Biological Station, Michigan State University

2006. Adjunct Professor, Kalamazoo College

Research Interests I am broadly interested in the processes that control the development and maintenance of

ecological communities, with emphasis on patterns of species diversity, invasion, and the

ecosystem production. I approach these topics by testing ecological theory and look for new

ideas that can be used to guide the management and restoration of ecosystems. Below are some

specific examples my research:

Effects of Soil Heterogeneity on Plant Diversity

Environmental heterogeneity is one of the most intuitive explanations for variation in diversity.

For example, plant diversity is expected to increase with soil heterogeneity. A large number of

observational studies that have measured resources such as light, soil moisture, soil nitrogen or

other soil variables report an increase in plant diversity with increased heterogeneity of these

resources. Surprisingly, experimental field experiments have found little support for this

relationship. Using a novel approach, Brandon Williams and I have found that plant diversity

increases with experimentally created soil heterogeneity at least during the early phases of

community assembly (see images and citation below). Currently, we monitoring whether these

patterns are maintained over time and tracking how community assembly develops from initially

homogeneous or heterogeneous conditions.

Vertical soil profile illustrating different

rooting activity

Example of soil patch structure allocated to

heterogeneous and homogeneous plots (type

for is a mixture of strata 1-3)

see Williams & Houseman 2013 Journal of Plant Ecology

Williams, B. M. and G. R. Houseman. 2013. Experimental evidence that soil heterogeneity

enhances plant diversity during community assembly. Journal of Plant Ecology

DOI:10.1093/jpe/rtt056. Abstract

Effects of Seed Arrival Patterns on Plant Diversity

Stratum2

Stratum1

Mixed StratumCombination of

all 3 strata

Stratum3

Heterogeneous soils

4 4 4 4 4 4

4 4 4 4 4 4

4 4 4 4 4 4

4 4 4 4 4 4

4 4 4 4 4 4

4 4 4 4 4 4

Homogeneous soils

It is now well-documented that species pools limit plant diversity in grasslands (see publications

list). However, nearly all these studies use uniform seed addition patterns. In nature, seed

dispersal is very patchy depending on the size and density of the focal species. The

consequences of patchy dispersal are relatively unknown and have potentially important

implications for restoration approaches, which often use uniform application. Currently, I am

testing these ideas in a large field experiment in a species-poor, Kansas prairie. Early results

from this work suggest that weaker seedling competitors may benefit from patchy seed arrival

leading to an increase in species evenness and potentially richness (depending on scale). Work

on this project continues!

Houseman, G. R. 2013. Aggregated seed arrival alters plant diversity in grassland communities.

Journal of Plant Ecology DOI:10.1093/jpe/rtt044. Abstract

Invasive Species: searching for an Achilles’ heel

Although invasive species can have large negative effects on the structure and function of native

ecosystems, they do provide an interesting opportunity to test underlying ecological principles

while trying to find ways to minimize their effects. Currently, we are testing how propagule

pressure (immigration rate) influences the probability of invasion among systems that vary in

soil fertility and disturbance regimes. We are also testing in the field and lab several potential

competitive mechanisms by which Lespedeza cuneata (sericea) invades native grasslands in

Kansas.

Coykendall, K. E. and G. R. Houseman. 2013. Lespedeza cuneata invasion alters oils

facilitating its own growth. Biological Invasions DOI:10.1007/s10530-013-0623-8. Abstract

Houseman, G. R., B. L. Foster and C. E. Brassil. 2013 Propagule pressure-invasibility

relationships: Testing the influence of soil fertility and disturbance with Lespedeza cuneata.

Oecologia DOI:10.1007/s00442-013-2781-x. Abstract

Wong, B. M., G. R. Houseman, S. E. Hinman and B. L. Foster. 2013. Invasive Plant Science

and Management 5:487-493. Abstract

Community Assembly and the Development of Diversity

While species pools and immigration are likely to influence diversity, it is unclear whether the

results are sensitive to the sequence of colonization events (community assembly). If

communities are structured by the interaction between species traits and environmental

conditions, community assembly is predicted to be a deterministic process. However, neutral

theory predicts that community assembly is a stochastic process driven by births, deaths,

immigration and evolution. Currently, Bryan Foster and I are testing the relative importance of

these neutral and niche based processes on community assembly in northeast Kansas. In this

experiment, we are manipulating species diversity and composition of plant species. After

removing extant species, we seeded 240 plots in various combinations of plant species diversity

and species traits. We are monitoring changes in diversity through time as a function of initial

species composition (note differences among plots marked by the white posts in the pictures

below) In addition to providing a strong test of ecological theory, the results will quantify how

initial diversity and species composition impact the development and maintenance of plant

diversity in grassland restorations.

Community Responses to Perturbations

Because the outcome of species interactions is dependent on environmental conditions, climate

change—including alteration of atmosphere deposition of N—may alter the structure of

communities. One interesting way to test this for communities is to quantify the variability

(dispersion) of communities in response to perturbations. For example, in a long-term nutrient

addition experiment in low-productivity sand prairie, we found that increased fertility reduced

diversity at small scales, but also led to greater variability in plant community composition than

unfertilized plots. This increased variability following perturbation suggests that it may be

difficult to predict the response of communities to human alteration of environmental conditions.

Currently, we have an experiment underway to test how initial conditions may influence the

community dispersion in grassland systems.

Houseman, G. R., G. G. Mittelbach, H. L. Reynolds, and K. L. Gross. 2008. Perturbations alter

community convergence, divergence, and formation of multiple community states Ecology

89:2172-2180. Abstract

Effects of herbivore diversity on native plant communities

Herbivores can have strong effects on native plant biomass, but little is known about how

different herbivore groups may independently or interactively effect plant species. Leland

Russell and I are testing this idea by reducing the access by insect and non-bovine mammals in a

restored Kansas grassland (see below). Additionally, fertilizer is applied to half of the plots to

test whether the effects of these herbivore groups vary with soil fertility.

Community

State

Community

State

Community

State

1 community

state

1 community

state

A

multiple

community

states

D

B

Initial Perturbed

Community

State

C

1 or no clear

community state

Convergence

Divergence

(Alternate States)

Peer-Reviewed Publications Shah, M. A., R. M. Callaway, T. Shah, G. R. Houseman, R. W. Pal, S. Xiao, W. Luo, C.

Rosche, Z. A. Reshi, D. P. Khasa and S. Chen. 2014. Conyza canadensis suppresses plant

diversity in its nonnative ranges but not at home: A transcontinental comparison. New

Phytologist DOI:10.1111/nph.12733 . Abstract

Williams, B. M. and G. R. Houseman. 2013. Experimental evidence that soil heterogeneity

enhances plant diversity during community assembly. Journal of Plant Ecology

DOI:10.1093/jpe/rtt056. Abstract

Houseman, G. R., B. L. Foster and C. E. Brassil. 2013 Propagule pressure-invasibility

relationships: Testing the influence of soil fertility and disturbance with Lespedeza cuneata.

Oecologia DOI:10.1007/s00442-013-2781-x. Abstract

Houseman, G. R. 2013. Aggregated seed arrival alters plant diversity in grassland communities.

Journal of Plant Ecology DOI:10.1093/jpe/rtt044. Abstract

Coykendall, K. E. and G. R. Houseman. 2013. Lespedeza cuneata invasion alters oils

facilitating its own growth. Biological Invasions DOI:10.1007/s10530-013-0623-8. Abstract

Wong, B. M., G. R. Houseman, S. E. Hinman and B. L. Foster. 2013. Invasive Plant Science

and Management 5:487-493. Abstract

Houseman, G. R. and K. L. Gross. 2011. Linking grassland plant diversity to species pools,

sorting and plant traits. Journal of Ecology 99:464-472. Abstract

B. L. Foster, K. Kindscher, G. R. Houseman, C. A. Murphy. 2009. Effects of hay management

and native species sowing on grassland community structure, biomass, and restoration.

Ecological Applications 19:1884-1896. Abstract

Houseman, G. R., G. G. Mittelbach, H. L. Reynolds, and K. L. Gross. 2008. Perturbations alter

community convergence, divergence, and formation of multiple community states Ecology

89:2172-2180. Abstract

Reynolds, H. L., G. G. Mittelbach, T. Darcy-Hall and G. R. Houseman, K. L. Gross. 2007. No

effect of varying soil resource heterogeneity on plant species richness in a low fertility grassland.

Journal of Ecology 95:723-733. Abstract

Houseman, G. R. and K. L. Gross. 2006. Does ecological filtering across a productivity gradient

explain variation in species pool-richness relationships? Oikos 115:148-154. Abstract

Suding, K. N., K. L. Gross, and G. R. Houseman. 2004. Alternative states and positive

feedbacks in restoration ecology. Trends in Ecology and Evolution 19:46-53. Abstract

Houseman, G. R. and R. C. Anderson. 2002. Effects of jack pine plantations on Kirtland’s

warbler nest habitat and barrens flora. Restoration Ecology 10:27-36. Abstract

Anderson, R. C., R. M. Anderson and G. R. Houseman. 2002 American Ginseng. Native Plants

Journal 3:93-97, 100-105. Abstract

External Research Grants NSF Kansas EPSCoR (2010) “Can spatial variability created by dispersal explain the

accumulation of biodiversity” ($39,000)

USDA-NRI (2006) “Does propagule pressure change invasion risk under different agricultural

management regimes” ($125,000)

NSF Doctoral Dissertation Improvement Grant 0308856 with Kay Gross (2003) “Species pools

and plant traits as constraints on species diversity across productivity gradients” ($10,000)

Courses Taught at Wichita State University BIOL211 General Biology II

BIOL503 Taxonomy and Geography of Flowering Plants

BIOL560-561 Plant Ecology

BIOL610 Ecosystem Management and Restoration