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BIOLOGICAL SCIENCES

   Gregory R. Houseman, PhD  

Gregory Houseman

Gregory R. Houseman, PhD
Associate Professor of Biology

Office: 519 Hubbard Hall
Phone: (316) 978-5841
Email: greg.houseman@wichita.edu

ResearchGate Profile
 

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
2014-present.  Associate Professor, Wichita State University
2008-2014. 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 ecosystem production. I approach these topics by testing ecological theory and look for ways to use this understanding 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 observed species diversity patterns.  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 is higher under experimentally enhanced 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 strata associated with soil forming processes and rooting activity Example of soil patch structure allocated to heterogeneous and homogeneous plots (type 4 is a mixture of strata 1-3)

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Vertical soil profile illustrating different strata associated with soil forming processes and rooting activity Example of soil patch structure allocated to heterogeneous and homogeneous plots (type 4 is a mixture of strata 1-3)

 

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Process of creating plots.  Lower center/right illustrates plant community after three growing seasons.  
   
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.    

 


Effects of Seed Arrival Patterns on Plant Diversity
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 seed arrival 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, restored 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!
 

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Houseman, G. R. 2013. Aggregated seed arrival alters plant diversity in grassland communities. Journal of Plant Ecology DOI:10.1093/jpe/rtt044.     


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. We tested 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.

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Coykendall, K. E. and G. R. Houseman. 2013. Lespedeza cuneata invasion alters soils facilitating its own growth. Biological Invasions DOI:10.1007/s10530-013-0623-8.    

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.    

Wong, B. M., G. R. Houseman, S. E. Hinman and B. L. Foster. 2012. Targeting vulnerable life-stages of sericea lespedeza (Lespedeza cuneata) with prescribed burns. Invasive Plant Science and Management 5:487-493.    
 


 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 access to grassland plots 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.  

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Experiment ongoing....

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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 (see reference below). 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 (see community assembly experiment below).  Additionally, I am part of a working group (Avolio, La Pierre, Isbell, Grman, Johnson, Wilcox) attempting to extend these ideas to responses to global change.
 

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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.    
 


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, I am collaborating with Bryan Foster’s lab to test 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.
 

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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.

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.
 


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 .    

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.    

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.    

Houseman, G. R. 2013. Aggregated seed arrival alters plant diversity in grassland communities. Journal of Plant Ecology DOI:10.1093/jpe/rtt044.    

Coykendall, K. E. and G. R. Houseman. 2013. Lespedeza cuneata invasion alters soils facilitating its own growth. Biological Invasions DOI:10.1007/s10530-013-0623-8.    

Wong, B. M., G. R. Houseman, S. E. Hinman and B. L. Foster. 2012. Targeting vulnerable life-stages of sericea lespedeza (Lespedeza cuneata) with prescribed burns. Invasive Plant Science and Management 5:487-493.    

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

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

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

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

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

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

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

Anderson, R. C., R. M. Anderson and G. R. Houseman. 2002 American Ginseng. Native Plants Journal 3:93-97, 100-105


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
 

Biol. 211. General Biology II. (4). 3R; 2L. (OFFERED FALL & SPRING) Introduces fundamental concepts of biology as they apply to levels of organization from organisms through ecosystems. Focuses on morphology, physiology, diversity and ecology of organisms. Introduces growth and anatomy, transport of materials, regulatory mechanisms and reproduction in plants; and, nutrient procurement, circulation, neural and hormonal regulation, reproduction, immune responses and behavior in animals. Principles of ecology presented include population growth and regulation; interspecific interactions and food webs; and, energy flow and material cycling though ecosystems. The laboratory includes a survey of organismal diversity including prokaryotes, protists, fungi, plants and animals; and, emphasizes evolutionary trends in the plant and animal kingdoms. Students may not receive credit for both Biology 203 (no longer offered) and Biology 211. Students wishing to repeat Biol. 203 may enroll in this course, subject to the credit limitations indicated above. Prerequisite: Biology 210. Concurrent enrollment in Chem. 212 is recommended.

Biol. 503. Taxonomy and Geography of Flowering Plants. (4). (OFFERED EVERY SUMMER) This course will provide an introduction to the identification, classification and geography of flowering plants. At the end of this course, students will be able to 1) recognize a core set of plant species common to south-central Kansas, 2) recognize key traits utilized to identify plant species, 3) use dichotomous keys to identify unknown plant species, and 4) explain relationships between plant occurrence and plant ecology and geography. 

Biol 560. Plant Ecology (2). 2 R. (OFFERED FALL ODD YEARS) This course will focus on identifying and explaining key ecological patterns found in plant communities.   Although factual knowledge will be important, the development of new knowledge will be emphasized by integrating what is known with new empirical tests, models, and re-analysis of published data.   This emphasis on the process of science over historical understanding will require students to synthesize information, apply knowledge to new situations, and develop and test hypotheses.  For this reason, the lecture and the lab will be fully integrated with no clear distinction between lab and lecture periods allowing maximum flexibility to conduct investigations in the field or lab.  In addition, students will learn methods for quantifying patterns in the field and laboratory and an introduction to key statistical approaches.  Because lab and lecture are integrated, students must be enrolled in in BIOL560 and BIOL561 concurrently.  Prerequisite: BIOL 418 or instructor approval

Biol 561. Plant Ecology Laboratory (2). (OFFERED FALL ODD YEARS) See BIOL560 for explanation and requirements.

Biol 610G. Ecosystem Management & Restoration (3). (OFFERED SPRING ODD YEARS) This course will focus on the application of ecological principles to the design, implementation, and evaluation of land management plans and restoration projects.  In the first section of the course, we will survey the ecological principles and socio-economic realities that must be integrated into land management plans.   The second section of the course will focus on case studies representing a wide-range of ecological systems to illustrate the application of ecological principles to real-world situations.  The final section of the course will focus on the development of student management plans for degraded ecosystems in south-central Kansas.  Prerequisite: BIOL 418 or instructor approval

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