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 six specific examples of my research:

Effects Soil Heterogeneity and Species Aggregation on Plant Diversity

Environmental heterogeneity is one of the most intuitive explanations for differences in plant diversity within and among communities. This view is corroborated by a number of observational studies that successfully relate resources such as light, soil moisture, soil nitrogen or other soil variables to plant diversity patterns. Surprisingly, experimental field experiments have failed to support the observational relationship calling into question whether fine-scale soil heterogeneity is important to plant diversity. Using a unique experimental 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 below).

One shortcoming of our initial experiment is that species were sown uniformly across plots. This approach does remove seed limitation within plots, but does not represent the spatial heterogeneity created by non-random seed arrival found in natural communities and that source of spatial structure may be very important to species coexistence and diversity. For example, in a previous experiment I found that spatially aggregated seed dispersal can enhance plant diversity in the short (Houseman 2014 J of Plant Ecology) and long term (unpublished data). We have recently been funded by the National Science Foundation to test the relative importance spatially aggregated seed and soil heterogeneity on plant diversity. Once again we are using the soil heterogeneity manipulation similar that Williams & Houseman 2014 but adding plant spatial aggregation (40 species sown uniformly or in aggregated distributions) at two different spatial scales (patch sizes of 0.04 and 0.16 m2). In addition to conducting the experiment in a tallgrass prairie in Kansas (warm-season grassland), we have a second identical experiment in a cool season grassland located near Tartu, Estonia. This is a collaborative project with Bryan Foster (University of Kansas), Tony Golubski (Kennesaw State University), and Lauri Laanisto (Estonian University of Life Sciences).

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

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.

Schouten, O. S. and Houseman, G. R. (online) Effect of soil heterogeneity and endogenous processes on plant spatial structure. Ecology. doi.org/10.1002/ecy.2837

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Restoration of grasslands across a precipitation gradient: Trophic links and a return of grazers

Given the loss of North American grasslands over the past two centuries, restoring and managing grassland is an important conservation issue. The Conservation Reserve Program (CRP) is a USDA program that has reestablished grasslands in areas dominated by row-crop agriculture, provided critical habitat for many grassland organisms, and has been ongoing for more than three decades. In Kansas, the CRP program currently has over 2 million acres—much of which is re-established, native grassland; however, there is currently no dominant grazer on most of these sites, despite the critical role that bison historically played in these systems. We are testing the functional linkages among plants, insects, and birds across these restored grasslands. We know that the plant community provides structure and food resources for insects. In turn, insects are a protein-rich food resource that is important for bird, nest success. Additionally, many grassland birds rely on the plant community for predator protection and additional food resources. We examining these structural and functional linkages among the three trophic levels to quantify the success of these restored systems and determine whether the careful utilization of cattle grazing can enhance habitat heterogeneity and increase wildlife diversity and abundance. However, the potential benefits of these grazers are likely to vary with plant productivity. Consequently, we are examining the responses across the major precipitation gradient found in Kansas that creates systematic variation in plant productivity (e.g. short to tallgrass prairie). Furthermore, these sites will include two CRP plantings (CP2 and CP25), which differ in the number of forbs planted. In total, the project will include 108 CRP sites across Kansas. In addition to my lab, the research team includes Mary Liz Jameson (entomologist, Wichita State University) and Bill Jensen (avian ecologist, Emporia State University).

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Invasive Species: searching for an Achilles’ heel

My lab has been working on the ecology of sericea lespedeza (Lespedeza cuneata) in both restored and grazed prairie. Specifically, we have addressed early invasion, timing of fire, plant-soil feedbacks, soil legacies, dispersal, negative density-dependent germination, and a landscape model addressing spread and control (see references below). Currently, Esra Buyuktahtakin (Wichita State University) and I have a USDA grant to test and refine our landscape model across multiple ranches in eastern Kansas. Our preliminary work on the optimization model relied on very limited data available from the literature or unpublished data. The goal for this next project is to collect data at realistic scales in grazed prairies which are often heavily invaded in Kansas and are often grasslands of high conservation value. The initial model predicted that the most cost effective control of L. cuneata would occur at the 3-year intervals because there was a 1-2 year delay before any specific location was able to recover from the seedbank and begin to spread. We are testing this prediction by applying herbicide to 50, one-acre plots in which herbicide is applied at 1, 2, or 3 year intervals. These plots are distributed across multiple ranches and various levels of plant productivity. In addition to refining our economic model, we hope that comprehensive quantification of demographic characteristics under different cattle management and soil conditions will yield new insights into the ecology of the plant and possibly a weakness that we could use to control sericea with non-chemical methods. The Tallgrass Legacy Alliance is also providing financial support to cover additional work on seedbank and methods for detecting and tracking the spread of sericea across large landscapes.

Sericea lespedeza (Lespedeza cuneata) Research

• Quick, Z. I., G. R. Houseman and I. E. Buyuktahtakin. 2017. Assessing the importance of wind and mammals as seed dispersal vectors in an invasive legume. Weed Research 57:35-43. DOI: 10.11/wre.12232 Abstract
• Foster, B. L., G. R. Houseman, D. R. Hall and S. E. Hinman. 2015 Does tallgrass prairie restoration enhance the invasion resistance of post-agricultural old-fields? Biological Invasions 17:3579-3590. DOI: 10.1007/s10530-015-0979-z
• Houseman, G. R. and *A. K. Mahoney (2015). Intraspecific seed interactions alter seedling emergence of Lespedeza cuneata under field conditions. Population Ecology 57:539-544, DOI: 10.1007/s10144-015-0495-0. Abstract
• Büyüktahtakin, I. E., *E. Y. Kibis, *H. I. Cobuloglu, GR. Houseman and *J. T. Lampe. (2015). An age-structured bio-economic model of invasive species management: Insights and strategies for optimal control. Biological Invasions 17:2545-2563, DOI: 10.1007/s10530-015-0893-4.
• 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. Abstract
• 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. 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.
• 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. Abstract

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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.

Experiment ongoing....

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Community Convergence and Divergence in Response 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) applying these ideas to plant community responses to global change (http://corredata.weebly.com/).

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.

Avolio, M. L., K. J. La Pierre, G. R. Houseman, S. E. Koerner, E. Grman, F. Isbell, D. S. Johnson and K. R. Wilcox. 2015. A framework for quantifying the magnitude and variability of community responses to global change drivers. Ecosphere 6:art280. Abstract

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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.

Experiment ongoing....

Working Groups

CoRRE (COmmunity Responses to Resource Experiments). Initially funded by the LTER network, this working group is attempting to compile ecological community data from experiments that manipulate at least one resource (e.g. water, light, nutrients, etc.). Most of the data available in the literature are not useful for meta-analysis because the published information is highly simplified (richness or evenness) or is incomparable (e.g. ordination diagrams). Our working group has complied 101 datasets thus far. In addition to a conceptual paper (Avolio et al. 2015), several other papers are currently in preparation. http://corredata.weebly.com/

Wilcox, K. R. T., A. T.; Koerner, S. E.; Grman, E.; Hallett, L. M.; Avolio, M. L.; La Pierre, K. J.; Houseman, G. R.; Isbell, F.; Johnson, D. S.; Alatalo, J. M.; Baldwin, A. H.; Bork, E. W.; Boughton, E. H.; Bowman, W. D.; Britton, A. J.; Cahill, J. F.; Collins, S. L.; Du, G. Z.; Eskelinen, A.; Gough, L.; Jentsch, A.; Kern, C.; Klanderud, K.; Knapp, A. K.; Kreyling, J.; Luo, Y. Q.; McLaren, J. R.; Megonigal, P.; Onipchenko, V.; Prevey, J.; Price, J. N.; Robinson, C. H.; Sala, O. E.; Smith, M. D.; Soudzilovskaia, N. A.; Souza, L.; Tilman, D.; White, S. R.; Xu, Z. W.; Yahdjian, L.; Yu, Q.; Zhang, P. F.; Zhang, Y. H. 2017. Asynchrony among local communities stabilises ecosystem function of metacommunities. Ecology Letters 20:1534-1545. Abstract

Komatsu, K.J. M. L. Avolio, N. P. Lemoine, F. Isbell, E. Grman, G. R. Houseman, S. E. Koerner, D. S. Johnson, K.R. Wilcox, J. M. Alatalo, J. P. Anderson, R. Aertsm, S. G. Baer, A. H. Baldwin, J. Bates, C. Beierkuhnlein, R. T. Beloter, J. Blair, J. M. G. Bloor, P. J. Bohlen, E. W. Bork, E. H. Boughton, W. D. Bowman, A. J. Britton, J. F. Cahill Jr., E. Chaneton, N. R. Chiariello, J. Cheng, S. L. Collins, J. H. C. Cornelissen, G. Du, A. Eskelinen, J. Firn, B. Foster, L. Gough, K. Gross, L. M. Hallett, X. Han, H. Harmens, M. J. Hovenden, A. Jagerbrand, A. Jentsch, C. Kern, K. Klanderud, A. K. Knapp, J. Kreyling, W. Li, Y. Luo, R. L. McCulley, J. R. McLaren, J. P. Megonigal, J. W. Morgan, V. Onipchenko, S. C. Pennings, J. S. Prevéy, J. N. Price, P. B. Reich, C. H. Robinson, F. L. Russell, O. E. Sala, E. W. Seabloom, M. D. Smith, N. A. Soudzilovskaia, L. Souza, K. Suding, K. B. Suttle, T. Svejcar, D. Tilman, P. Tognetti, R. Turkington, S. White, Z. Xu, L. Yahdjian, Q. Yu, P. Zhang, and Y. Zhang. 2019. Global change effects on plant communities are magnified by time and number of global change factors imposed. Proceedings of the National Academy of Science (online). doi.org/10.1073/pnas.1819027116

C2E (Communities to Ecosystems) at NCEAS (National Center for Ecological Analysis and Synthesis). This group is an outgrowth of the CoRRE group and is led by Kim La Pierre, Meghan Avolio, and Kevin Wilcox. The goal of this new group is to 1) identify temporal patterns of plant community change in response to global change manipulations; 2) link these patterns of community change to changes in aboveground net primary productivity and carbon storage; and 3) incorporate community change into ecosystem models predicting functional responses to global change drivers.

Courses Taught at Wichita State University

• General Biology II (BIOL 211)
• Field Botany (BIOL 503)
• Ecosystem Management and Restoration (BIOL 610G)
• Plant Ecology (BIOL 610N)

• Komatsu, K.J. M. L. Avolio, N. P. Lemoine, F. Isbell, E. Grman, G. R. Houseman, S. E. Koerner, D. S. Johnson, K.R. Wilcox, J. M. Alatalo, J. P. Anderson, R. Aertsm, S. G. Baer, A. H. Baldwin, J. Bates, C. Beierkuhnlein, R. T. Beloter, J. Blair, J. M. G. Bloor, P. J. Bohlen, E. W. Bork, E. H. Boughton, W. D. Bowman, A. J. Britton, J. F. Cahill Jr., E. Chaneton, N. R. Chiariello, J. Cheng, S. L. Collins, J. H. C. Cornelissen, G. Du, A. Eskelinen, J. Firn, B. Foster, L. Gough, K. Gross, L. M. Hallett, X. Han, H. Harmens, M. J. Hovenden, A. Jagerbrand, A. Jentsch, C. Kern, K. Klanderud, A. K. Knapp, J. Kreyling, W. Li, Y. Luo, R. L. McCulley, J. R. McLaren, J. P. Megonigal, J. W. Morgan, V. Onipchenko, S. C. Pennings, J. S. Prevéy, J. N. Price, P. B. Reich, C. H. Robinson, F. L. Russell, O. E. Sala, E. W. Seabloom, M. D. Smith, N. A. Soudzilovskaia, L. Souza, K. Suding, K. B. Suttle, T. Svejcar, D. Tilman, P. Tognetti, R. Turkington, S. White, Z. Xu, L. Yahdjian, Q. Yu, P. Zhang, and Y. Zhang. 2019. Global change effects on plant communities are magnified by time and number of global change factors imposed. Proceedings of the National Academy of Science (online). doi.org/10.1073/pnas.1819027116
• Schouten, O. S. and Houseman, G. R. 2019. Effect of soil heterogeneity and endogenous processes on plant spatial structure. Ecology (online).doi.org/10.1002/ecy.2837
• Russell, F. L and G. R. Houseman. 2019. Context dependency of insect and mammalian herbivore effects on tall thistle (Cirsium altissimum) populations. Journal of Plant Ecology 12:531-541. doi.org/10.1093/jpe/rty045
• Wilcox, K. R. T., A. T.; Koerner, S. E.; Grman, E.; Hallett, L. M.; Avolio, M. L.; La Pierre, K. J.; Houseman, G. R.; Isbell, F.; Johnson, D. S.; Alatalo, J. M.; Baldwin, A. H.; Bork, E. W.; Boughton, E. H.; Bowman, W. D.; Britton, A. J.; Cahill, J. F.; Collins, S. L.; Du, G. Z.; Eskelinen, A.; Gough, L.; Jentsch, A.; Kern, C.; Klanderud, K.; Knapp, A. K.; Kreyling, J.; Luo, Y. Q.; McLaren, J. R.; Megonigal, P.; Onipchenko, V.; Prevey, J.; Price, J. N.; Robinson, C. H.; Sala, O. E.; Smith, M. D.; Soudzilovskaia, N. A.; Souza, L.; Tilman, D.; White, S. R.; Xu, Z. W.; Yahdjian, L.; Yu, Q.; Zhang, P. F.; Zhang, Y. H. 2017. Asynchrony among local communities stabilises ecosystem function of metacommunities. Ecology Letters 20:1534-1545. Abstract
• *Quick, Z. I., G. R. Houseman and I. E. Buyuktahtakin. 2017. Assessing the importance of wind and mammals as seed dispersal vectors in an invasive legume. Weed Research 57:35-43. Abstract.
• Houseman, G. R., M. S. Kraushar and C. M. Rogers. 2016. The Wichita State University Biological Field Station: Bringing breadth to research along the precipitation gradient in Kansas. Transactions of the Kansas Academy of Science 119:27-32. Abstract
• Avolio, M. L., K. J. La Pierre, G. R. Houseman, S. E. Koerner, E. Grman, F. Isbell, D. S. Johnson and K. R. Wilcox. 2015. A framework for quantifying the magnitude and variability of community responses to global change drivers. Ecosphere 6:art280. Abstract
• Foster, B. L., G. R. Houseman, D. R. Hall and S. E. Hinman. 2015 Does tallgrass prairie restoration enhance the invasion resistance of post-agricultural old-fields? Biological Invasions 17:3579-3590. Abstract
• Büyüktahtakin, I. E., *E. Y. Kibis, *H. I. Cobuloglu, G. R. Houseman and *J. T. Lampe. (2015). An age-structured bio-economic model of invasive species management: Insights and strategies for optimal control. Biological Invasions 17:2545-2563, DOI: 10.1007/s10530-015-0893-4. Abstract
• Houseman, G. R. and *A. K. Mahoney (2015). Intraspecific seed interactions alter seedling emergence of Lespedeza cuneata under field conditions. Population Ecology 57:539-544, DOI: 10.1007/s10144-015-0495-0. Abstract
• *Williams, B. M. and G. R. Houseman. (2014). Experimental evidence that soil heterogeneity enhances plant diversity during community assembly. Journal of Plant Ecology 7:461-469, DOI:10.1093/jpe/rtt056. Abstract
• *Coykendall, K. E. and G. R. Houseman. 2014. Lespedeza cuneata invasion alters soils facilitating its own grown. Biological Invasions 16:1735-1742. Abstract
• 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.

*Denotes Wichita State University undergraduate or graduate student

• 2018-present. Field Station Director, Wichita State University
• 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

• NSF EPSCoR (2017) “RII Track-1: Microbiomes of aquatic, plant and soil systems (MAPS) mediating sustainability: An observation and experimental network across Kanas precipitation and land use gradients” G. R. Houseman (numerous collaborators; Houseman is the sole WSU PI); WSU Funded $428,792
• Kansas Department of Wildlife, Parks, and Tourism (2017) “Linking CRP Grassland Management to Plants, Insects, and Birds” W. Jensen PI, G. R. Houseman, and M. L. Jameson CoPIs; Funded $1,053,947
• Young Faculty Scholar Award, Wichita State University 2016.
• NSF-DEB (2016) travel supplement for “Interactive effects of exogenous and endogenous spatial heterogeneity on plant diversity” G. R. Houseman PI; Funded $12,606.
• Tallgrass Legacy Alliance (2016) “Improving our understanding of the spread and control of the invasive species—sericea lespedeza” G. R. Houseman PI; Funded $38,351.
• USDA-AFRI (2016) “Integrating modeling and field experiments to guide weed management in rangeland systems” G. R. Houseman PI and I. E. Büyüktahtakin Co-PI; Funded $430,822.
• NSF-DEB (2015) “Interactive effects of exogenous and endogenous spatial heterogeneity on plant diversity” G.R. Houseman PI, B. L. Foster, Antonio Golubski Co-P.I.s; Funded $747,269.
• National Socio-Environmental Synthesis Center: LTER Postdoctoral Fellowship (2015) “Developing new metrics for studying holistic community changes—a necessary new frontier in the Anthropocene” M. Avolio (PI), G. R. Houseman (co-PI; postdoctoral co-advisor); Funded to cover Postdoctoral salary along with travel and stipend for Houseman.
• NSF Kansas EPSCoR (2010) “Can spatial variability created by dispersal explain the accumulation of biodiversity” G. R. Houseman PI; Funded $39,000.
• USDA-NRI (2006) “Does propagule pressure change invasion risk under different agricultural management regimes” G. R. Houseman PI; Bryan Foster CoPI; Funded $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” Funded $10,000.