Much of my work at the Illinois Natural History Survey focuses on rare species biology, conservation in transportation corridors, invasive plants, and plant-insect interactions. I serve as the lead of the Biological Surveys and Assessment Program and was a long-time member of the Critical Trends Assessment Program. 

Additional research interests include

• Monarch butterfly interactions with milkweeds, nectar plants, and aphids
• Phenological shifts in plants with climate warming
• Plant reproductive biology
• Population genetics
• Demography
• Effects of pesticide drift in natural areas
• Conservation applications of remote sensing

I'm also interested in all things Celastrus (aka bittersweets or staff vines), Sangamon phlox and relatives, and the new invasion by Asian copperleaf in the Midwest.

Illinois Experts Profile

Google Scholar profile

Ph.D. in Biological Sciences, University of Illinois Chicago — advised by Dr. Mary V. Ashley

B.S. in Biological Sciences, University of Illinois Chicago

Many Midwestern retailers sell mislabeled invasive vines

Study tracks decades of life cycle changes in nonwoody plants

Aggressive, non-native wetland plants squelch species richness more than dominant natives do

Spring forest flowers likely a key to bumble bee survival, Illinois study finds

Working on monarchs: Illinois holds a central role in butterflies “too cool to lose”

Milkweed losses in Illinois and what it means for monarch butterfly declines

Trivellone V, Dietrich CH, Panassiti B, Pagels A, Janssen E, Marcum PB, Johnson S, McIntyre SD, Feist MA, Zaya DN, Benson TJ, Molano-Flores B. Vegetation mediates the effect of management and habitat on Auchenorrhyncha species richness, but not community quality, in restored grasslands. Journal for Nature Conservation 91:127231. https://doi.org/10.1016/j.jnc.2026.127231

Quiroz E, Ashley MV, Zaya DN. 2025. Aphid abundance and monarch butterfly oviposition in urban gardens. Journal of Insect Conservation 29:84. https://doi.org/10.1007/s10841-025-00720-5

Charles B, Cox P, Keininger T, Maass N, Marcum P, Molano-Flores B, Skufca J, Spyreas G, Ulaszek E, Zaya DN. 2025. Illinois threatened and endangered plant S-rank update and a new Illinois Plant Watch List. Natural Areas Journal 45:169-182. https://doi.org/10.3375/2162-4399-45.3.5

Augspurger CK, Zaya DN. 2025. Growing season lengthens in a North American deciduous woody community from 1993-2021. Ecology and Evolution 15:e71226. https://doi.org/10.1002/ece3.71226

Choi DH, Morton IS, Darling LE, Wang J, Thapa B, Price EPF, Zaya DN, Fei S, Hardiman BS. 2025. Detecting Invasive shrub species by Utilizing High-Density Airborne LiDAR Data and Spectral Imagery. Urban Foresty & Urban Greening 107:128764. https://doi.org/10.1016/j.ufug.2025.128764

Chong JP, Minnaert‐Grote J, Zaya DN, Ashley MV, Coons J, Ramp Neale JM, Molano‐Flores B. 2024. Genetic Diversity and Structure of Physaria on the Kaibab Plateau: Implications for Conservation. Ecology and Evolution 14: e70523. https://doi.org/10.1002/ece3.70523

Zinnen J, Matthews JW, Zaya DN. 2024. Genetic diversity, reproductive success, and genetic differentiation from congeners in the narrow endemic Phlox pilosa ssp. sangamonensis. Journal of the Torrey Botanical Society 151(2):138-163. https://doi.org/10.3159/TORREY-D-23-00025.1

Zinnen J, Matthews JW, Zaya DN. 2024. Noteworthy Collections: First Record of a Natural Hybrid Between Phlox divaricata ssp. laphamii (Alph. Wood) Wherry and Phlox pilosa ssp. sangamonensis (Levin & D.M. Sm.). Castanea 88(2):184-190. https://doi.org/10.2179/0008-7475.88.2.184

Johnson SA, Zaya DN, Coons J, Molano-Flores B. 2023. Field validation as a tool for mitigating uncertainty in species distribution modeling for conservation planning. Conservation Science and Practice. Published online. http://doi.org/10.1111/csp2.12978

Roche M, Pearse IS, Sofaer HR, Kivlin S, Zaya DN, Spyreas G, Kalisz S. 2023. Invasion-mediated mutualism disruption is evident across heterogeneous environmental conditions and varying invasion intensities. Ecography 2023(7): e06434. https://doi.org/10.1111/ecog.06434 

Johnson SA, Coons J, Zaya DN, Molano-Flores B. 2023. Assessing the reproductive ecology of a rare mint, Macbridea alba, an Endangered Species Act protected species. Plants 12(7):1485. https://doi.org/10.3390/plants12071485

Petri L, Beaury EM, Corbin J, Peach K, Sofaer H, Pearse IS, Early R, Barnett DT, Ibáñez I, Peet RK, Schafale M, Wentworth TR, Vanderhorst JP, Zaya DN, Spyreas G, Bradley BA. 2023. SPCIS: Standardized Plant Community with Introduced Status database. Ecology e3947. https://doi.org/10.1002/ecy.3947

Zinnen J, Charles B, Zaya DN, Matthews JW. 2022. Functional traits and responses to nutrient and mycorrhizal addition are inconsistently related to wetland plant species’ coefficients of conservatism. Wetlands Ecology and Management. https://doi.org/10.1007/s11273-022-09877-1

Molano-Flores B, Coons J, Zaya DN. 2021. Population Surveys and Viability Assessments for Coryphantha scheeri var. robustispina, a Federally Protected Cactus of the Sonoran Desert. Natural Areas Journal 41(3):213-217. https://doi.org/10.3375/043.041.0308

Mola JM, Richardson LL, Spyreas G, Zaya DN, Pearse IS. 2021. Long-term surveys support declines in early season forest plants used by bumblebees. Journal of Applied Ecology 58(7):1431-1441. https://doi.org/10.1111/1365-2664.13886

Zaya DN, Leicht-Young SA, Pavlovic NB, Ashley MV. 2021. Heterospecific pollination by an invasive congener threatens the native American bittersweet, Celastrus scandens. PLOS ONE 16 (3): e0248635. https://doi.org/10.1371/journal.pone.0248635

Zinnen J, Spyreas G, Zaya DN, Matthews JW. 2021. Niche ecology in Floristic Quality Assessment: Are conservative species more specialized? Ecological Indicators 121: 107078. https://doi.org/10.1016/j.ecolind.2020.107078

Augspurger CK, Zaya DN. 2020. Concordance of long-term shifts with climate warming vary among phenological events and herbaceous species. Ecological Monographs 90(4):e01421. https://doi.org/10.1002/ecm.1421

Janssen ED, Zaya DN, Yao LX, Molano-Flores B. 2020. Assessment of seed germinability after prolonged seed storage for Synthyris bullii (Plantaginaceae), a rare endemic of the Midwestern USA. The American Midland Naturalist 183(1):116-129. https://doi.org/10.1637/19-029

Molano-Flores B, Zaya DN, Baty J, Spyreas G. 2019. An assessment of the vulnerability of Illinois’ rarest plant species to climate change. Castanea 84(2):115-127. https://doi.org/10.2179/0008-7475.84.2.115

Annis J, Coons J, Zaya DN, Molano-Flores B. 2019. Environmental influences on foliar anthocyanin production in Pinguicula planifolia (Lentibulariaceae). The Journal of the Torrey Botanical Society 146(4):269-277. https://doi.org/10.3159/TORREY-D-18-00043.1 

Pearse IS, Sofaer HR, Zaya DN, Spyreas G. 2019. Non-native plants have greater impacts because of differing per-capita effects and nonlinear abundance-impact curves. Ecology Letters 22(8):1214-1220. https://doi.org/10.1111/ele.13284

Kim ES, Zaya DN, Fant JB, Ashley MV. 2019. Reproductive trade-offs maintain bract color polymorphism in Scarlet Indian paintbrush (Castilleja coccinea). PLOS ONE 14(1):e0209176. https://doi.org/10.1371/journal.pone.0209176

Primer SB, Molano-Flores B, Zaya DN, Helm C, Coons J. 2018. Effect of habitat structure on reproduction and prey capture of a rare carnivorous plant, Pinguicula lutea.  Arthropod-Plant Interactions 12:671-683

Zaya DN, Leicht-Young SA, Pavlovic NB, Hetrea CS, Ashley MV. 2017. Mislabeling of an invasive vine (Celastrus orbiculatus) as a native plant (C. scandens) in horticulture. Integrated Plant Science and Management 10:313-321

Koenig WD, Knops JHM, Pesendorfer MB, Zaya DN, Ashley MV. 2017. Drivers of synchrony of acorn production in the valley oak (Quercus lobata) at two spatial scales. Ecology 98:3056-3062

Zaya DN, Pearse IS, Spyreas G. 2017. Long-term trends in Midwestern milkweed abundances and their relevance to monarch butterfly declines. BioScience 67:343-356. https://doi.org/10.1093/biosci/biw186

Zaya DN, Molano-Flores B, Feist MA, Koontz JA, Coons J. 2017. Assessing genetic diversity for the USA endemic carnivorous plant Pinguicula ionantha R.K. Godfrey (Lentibulariaceae). Conservation Genetics 18:171-180 

Zaya DN, Leicht-Young SA, Pavlovic NB, Feldheim KA, Ashley MV. 2015. Genetic characterization of hybridization between native and invasive bittersweet vines (Celastrus spp.). Biological Invasions 17:2975-2988

Kim ES, Zaya DN, Fant JB, Ashley MV. 2015. Genetic factors accelerate demographic decline in rare Asclepias species. Conservation Genetics 16(2):359-369

Ruffatto DM, Zaya DN, Molano-Flores B. 2015. Reproductive success of the gynodioecious prairie species Lobelia spicata Lam. (Campanulaceae): female frequency, population demographics, and latitudinal patterns. International Journal of Plant Sciences 176:120-130

Grundel R, Frohnapple KJ, Zaya DN, Glowacki GA, Weiskerger C, Patterson TA, Pavlovic NB. 2014. Geographic coincidence of abundance, richness, conservation value, and response to climate of U.S. landbirds. Ecological Applications 24:791-811

Abraham ST, Zaya DN, Koenig WD, Ashley MV. 2011. Interspecific and intraspecific pollination patterns of valley oak, Quercus lobata, in a mixed stand in coastal central California. International Journal of Plant Sciences 172:691-699

Weekley CW, Zaya DN, Menges ES, Faivre AE. 2010. Multiple causes of seedling rarity in scrub plum, Prunus geniculata (Rosaceae), an endangered shrub of the Florida scrub. American Journal of Botany 97:144-155

Zaya DN, Howe HF. 2009. The anomalous Kentucky coffeetree: megafaunal fruit sinking to extinction? Oecologia 161:221-226