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Entomology 4112A Plant Sciences Building 4291 Fieldhouse Drive College Park, Maryland 20742-4454


Plant Science & Landscape Architecture 2102 Plant Sciences Building 4291 Fieldhouse Drive College Park, Maryland 20742


  • Understand patterns of biological diversity as well as the relationships between these patterns and the ecological and evolutionary processes that have created them thereby applying this understanding to developing effective conservation approaches and to predict effects of changing patterns and processes
  • Applying and integrating techniques from traditionally disparate fields including systematics, population genetics, autecology, synecology, landscape ecology, and restoration ecology
  • Testing basic assumptions on which much of conservation biology is based as it is typically not possible to collect all desirable data on a particular problem in timeframes necessary to contribute to management decisions
  • Verifying the validity of such assumptions is critical to identifying where general principles apply and where acquiring new scientific information is necessary for sound decision-making. It also assesses risks of making decisions without complete information



I am committed to conducting research on problems faced by practitioners, and communicating my results such that they provide specific, practical guidance for conservation policy and management. I am committed to training students and post-doctoral researchers to work at the interface between science, policy, and practice.

Working on a wide variety of conservation issues has given me the opportunity to integrate techniques from traditionally disparate fields  to quantify genetic, species, and community diversity.  I consequently draw on a variety of disciplines and methodologies including population genetics, systematics, and population, community and landscape ecology and restoration ecology. Research in the lab also spans a range of localities and scales, including the Chesapeake Bay, southern California, and the Atlantic coastal plain.

Beyond addressing questions in specific conservation situations I test basic assumptions on which conservation biology is based. Because it is typically not possible to collect all desirable data on a particular problem in timeframes necessary to contribute to management, practitioners rely on general principles derived from ecology, population genetics and population biology theory. Verifying the validity of such assumptions is critical to identifying where general principles apply and where acquiring new scientific information is necessary for sound decision-making.


Ph.D. University of California Riverside Botany

M.S. University of California Santa Barbara Ecology and Evolutionary Biology

B.S. Humboldt State University Environmental Biology and Conservation

Professional Work

Professional Positions Held: 

Academic Appointments at University of Maryland

2009–present Associate Professor, Department of Plant Science and Landscape Architecture (67%; 75% Teaching, 25% Research) & Department of Entomology (33%), University of Maryland, College Park.
2005–2009 Assistant Professor, University of Maryland, College Park.

Assistant Professor, Department of Natural Resource Sciences and Landscape Architecture. University of Maryland, College Park.

Administrative Appointments at University of Maryland


May 2011–present Director, Norton-Brown Herbarium (MARY), University of Maryland, College Park, MD.

Other Employment

2001–2003        Postdoctoral Research Associate, David H. Smith Conservation Research Fellow. University of Massachusetts, Department of Natural Resources Conservation, Amherst, MA. Laboratory of Kevin McGarigal.
2000–2001 Postgraduate Researcher. University of California, Riverside. Department of Botany and Plant Sciences. Riverside, CA. Laboratory of Norman C. Ellstrand

Assistant Forest Botanist. San Bernardino National Forest. Fawnskin, CA.

1983–1986 Ranger Naturalist. Channel Islands National Park. Ventura, CA.


Current Research: 

My research has one goal: to understand how to effectively and efficiently conserve all types of biological diversity, from genes to ecosystems. To do so I integrate theory and analytical approaches from multiple disciplines including population genetics and population, community and landscape ecology.

In some cases I study individual species to understand biological responses to human-caused impacts. However, increasing numbers of species are declining towards extinction faster than scientists can study them as habitat is converted to human use and climates change. To guide conservation of poorly known species I use large, cross-species comparisons from databases that I develop to identify how and when generalized conservation approaches can be effective for species about which we know little.

A primary question I ask is, how do habitat loss and fragmentation affect species and ecological processes? In particular I seek to understand how the spatial distribution of genetic diversity relates to habitat amount and configuration. I then ask how the distribution of genetic diversity affects potential for adaptation and acclimation to novel environmental conditions.

I also have contributed extensively by asking how effective and defensible current conservation approaches for Endangered Species are. Answering these questions requires expertise in a variety of disparate disciplines, sophisticated computing and statistical analyses, and use of complex DNA-based techniques. Beyond scientific inquiry, I develop methods that facilitate sound and justifiable policy decisions in the real world of incomplete data. Through this body of work, I create knowledge that is of fundamental importance for policy makers as well as scientists.

Habitat Fragmentation and the Spatial Distribution of Biological Diversity:

Because habitat loss and fragmentation are leading causes of biodiversity decline, study of their effects underlies all of my research. My current work links genetic diversity with spatial habitat structure in human-altered landscapes and evaluates the effect of genetic diversity on persistence. These eco-evolutionary feedbacks are increasingly recognized as significant drivers of resilience, or lack thereof. My work contributes to conserving vital ecological and evolutionary processes that maintain biological diversity. The focal species for this work is Vallisneria americana (American wild celery), an aquatic plant native to eastern North America. In collaboration with Dr. Katia Engelhardt (UM Center for Environmental Science Appalachian Laboratory) and students, I have worked on this species in the Chesapeake Bay since 2006. More recently we expanded to the Western Atlantic coast from Florida to Maine, especially the Hudson River of New York.

Aquatic vegetation in the Chesapeake Bay has drastically declined (from an estimated 250,000 hectares at European contact to ~30,000 hectares) with far-reaching consequences for population genetic diversity, the health of the Bay, and the animals that depend on it. Through our own research and synthesis of the literature we address three fundamental questions in restoration that rely on how much genetic diversity is present within populations and potential for dispersal among populations. First, is active restoration necessary? If so, where should restoration activities take place to maximize benefits to ecological processes? Third, where should the donor plant material come from? Through these questions we have contributed to basic scientific understanding of potential for resilience of aquatic plants under changing conditions and we inform restoration actions.

Key to answering these questions is understanding the distribution of V. americana and its genetic diversity. We have found that despite being highly reduced in extent and existing in disconnected ephemeral patches (Lloyd et al. in press), V. americana has surprising levels of genetic diversity in the Chesapeake Bay (Lloyd et al. 2011). However, limited dispersal has resulted in three distinct genetic regions. Additionally, particular locations are dominated by one or a few genetic individuals (clones) and thus have low genetic diversity (Lloyd et al. 2011). We have shown that genetic diversity affects traits related to ecological function (Engelhardt et al. 2014) and reproduction (Marsden et al. 2014), we still seek to understand how separated patches contribute to the species’ genetic health in the Bay.


Endangered Species Recovery and Conservation

Through past work I led development of a web-based database of ~90 key data points from each approved recovery plan for 1,437 listed plant and animal species. These data have been a valuable resource for managers and researchers as this was the first compilation of such data from all recovery plans. I also led efforts to amass life history and demographic information for well-studied species that we are using to assess how well life history traits predict demography, a fundamental requirement of oft-recommended surrogate species approaches. Beyond using these data for our own research we have shared the demographic matrices through an international, public web-based database called COMPADRE (Salguero-Gómez, R., et al. 2016).

We published the most comprehensive assessment of listing and recovery under the Act since 1995 (Neel et al. 2012), that was highlighted in an editorial in BioScience. Key findings included that species are listed so late that they are too close to extinction for effective recovery, that abundance-related recovery objectives are too low to ensure species persistence, and that variation in recovery objectives across species calls into the question their scientific basis. Results indicating other approaches suggested for developing recovery objectives are problematic (Neel and Che-Castaldo 2013, Che-Castaldo and Neel 2012, Zeigler et al. 2013) have led us to develop practical solutions that will bring the best available science to bear on endangered species conservation. This body of work has generated invitations to present two briefings to the U.S. House of Representatives Natural Resource Committee, give numerous seminars to US Fish and Wildlife Service, speak in four symposia at international meetings (the Ecological Society of America and The Society for Conservation Biology), and participate in writing an invited Issues in Ecology synthesis (Evans et al. 2016) and a BioScience (Wolf et al. 2016) paper.

To provide solutions for issues raised by our research we are developing a landscape-level approach to endangered species recovery and model of extinction probability. This approach integrates intrinsic species traits and extrinsic threats using amounts and distribution of habitat, commonly held data for most species (Neel et al. 2014, Che-Castaldo and Neel 2016). We work closely with the US Fish and Wildlife Service to apply and test our methods. Further development and evaluation of the habitat-based method of conservation status evaluation and analysis of the record of endangered species recovery contained within recovery plans will continue to constitute a significant portion of my research program.



    Courses Taught: 

    PLSC226 PLANT DIVERSITY Spring 2014, Spring 2015, Spring 2016
    PLSC399 SPECIAL PROBLEMS PLSC Spring 2014, Spring 2015, Summer 2015, Spring 2016, Summer 2016
    PLSC481 VEGETATION ASSESSMENT Fall 2011, Fall 2014
    PLSC489K SUSTAINABLE TROPICAL ECO Winter 2011, Winter 2012
    PLSC489O PLANT TAXONOMY Spring 2014, Spring 2015, Spring 2016
    PLSC689C CONSERVATION BIOLOGY Fall 2010, Spring 2011, Fall 2011, Spring 2012, Fall 2012, Spring 2013, Fall 2013, Spring 2014, Fall 2014, Spring 2015, Spring 2016
    PLSC789F CRTQ PRMRY PLNT SCI LIT Spring 2015, Spring 2016


    Selected Publications: 

    Peer-Reviewed Journal Articles

    45. Frye, C. T.**, M. C. Neel. 2016. Benefits of Gene Flow Are Mediated by Individual Variability in Self-Compatibility in Small Isolated Populations of an Endemic Plant Species. Invited submission to a special issue on gene flow in Evolutionary Applications. Early View. DOI: 10.1111/eva.12437

    44. Lloyd, M. W.**, P. A. Widmeyer*, and M. C. Neel. 2016. Temporal variability in potential connectivity of Vallisneria americana in the Chesapeake Bay. Landscape Ecology 31:2307-2321. DOI:10.1007/s10980-016-0401-y

    43. Che-CastaldoJ. P.† M. C. Neel. 2016. Species-Level Persistence Probabilities for Recovery and Conservation Status Assessment. Conservation Biology 30:1297-1306.DOI: 10.1111/cobi.12728

    42. Evans, D. M., J. P. Che-Castaldo†, D. Crouse, F. W. Davis, T. H. Eason, R. Epanchin-Niell, C. H. Flather, K. Frohlich, D. D. Goble, Y. Li, T. D. Male, L. L. Master, M. C. Neel, B. R. Noon, C. Parmesan, M. W. Schwartz, J. M. Scott, B. K. Williams. 2016. Recovery of Endangered and Threatened Species in the United States. Issues in Ecology: 20:1–28.

    41. Wolf, S. H., B. Hartl, C. Carroll, J. Tutchton, M. C. Neel, N. D. Greenwald. 2015. Beyond PVA: Why recovery Under the Endangered Species Act is More Than Population Viability. BioScience 65:200–207. DOI:10.1093/biosci/biu218

    40. Salguero-Gómez, R., O. R. Jones, C. R. Archer… M. C. Neel (30th)…G. M Wardle, M. Franco, J. W. Vaupel (37 authors). 2015. The COMPADRE plant Matrix Database: An Open Online Repository for Plant Demography. Journal of Ecology 103:202–218: DOI:10.1111/1365-2745.12334

    39. Neel, M. C., H. Tumas*, B. E. West.** 2014. Representing Connectivity: Quantifying Effective Habitat Availability Based on Area and Connectivity for Conservation Status Assessment and Recovery. PeerJ, 2:e622. DOI:10.7717/peerj.622

    38. Engelhardt, K. A. M., M. W. Lloyd**, and M. C. Neel2014. Effects of Genetic Diversity on Conservation and Restoration Potential at Individual, Population and Regional Scales. Biological Conservation 179:6–16.DOI:10.1016/j.biocon.2014.08.011

    37. Marsden, BW.**, K. A. M. Engelhardt, M. C. Neel2013. Genetic Rescue versus Outbreeding Depression in Vallisneria americana: Implications for Mixing Seed Sources for Restoration. Biological Conservation 167:203–214. DOI:10.1016/j.biocon.2013.08.012

    36. Zeigler, S. L.**, J. P. Che-Castaldo†, M. C. Neel2013. Actual and Potential Use of Population Viability Analysis in Recovery of Plant Species Listed Under the U.S. Endangered Species Act. Conservation Biology 27:1265–1278. DOI: 10.1111/cobi.12130

    35. Lloyd, M. W.**, L. Campbell†, and M. C. Neel2013. The Power to Detect Recent Fragmentation Events Using Genetic Differentiation Methods. PloS One. 8: e63981. DOI:10.1371/journal.pone.0063981

    34. Neel, M. C., K. McKelvey, R. S. Waples, N. Ryman, M. W. Lloyd**, R. Short Bull, F. W. Allendorf, and M. K. Schwartz. 2013. Estimation of Effective Population Size in Continuously Distributed Populations: There Goes the Neighborhood. Heredity 111:189–99. DOI:10.1038/hdy.2013.37

    33. Kennedy, C. M.†, E. Lonsdorf, M. C. Neel, N. M. Williams, T. H. Ricketts, R. Winfree, et al. 2013. A Global Quantitative Synthesis of Local and Landscape Effects on Wild Bee Pollinators in Agroecosystems. Ecology Letters 16:584–599. DOI:10.1111/ele.12082

    32.Neel, M. C., J. P. Che-Castaldo†. 2013. Predicting recovery criteria for threatened and endangered plant species on the basis of past abundances and biological traits. Conservation Biology 27:385–397. DOI:10.1093/biosci/biu218

    31. Che-Castaldo, J. P.†, M. C. Neel2012. Testing Surrogacy Assumptions: Can Threatened and Endangered Plants be Grouped by Biological Similarity and Abundances? PloS One 7:e51659. DOI:10.1371/journal.pone.0051659

    30. Lloyd, M. W.**, R. K. Burnett Jr., K. A. M. Engelhardt, M. C. Neel2012. Does Genetic Diversity of Restored Sites Differ from Natural Sites? A Comparison of Vallisneria americana(Hydrocharitaceae) Populations Within the Chesapeake Bay. Conservation Genetics 13:753–765. DOI: 10.1007/s10592-012-0324-3

    29. Neel, M. C., A. K. Leidner†, A. Haines, D. D. Goble, J. M. Scott. 2012. By the Numbers: How is Recovery Defined by the U.S. Endangered Species Act? BioScience 62:646–657. DOI:10.1525/bio.2012.62.7.7

    28. Kennedy, C. M.**, E. H. Campbell Grant, M. C. Neel, W. F. Fagan, and P. P. Marra. 2011. Landscape Matrix Mediates Occupancy Dynamics of Neotropical Avian Insectivores. Ecological Applications 21:1837–1850. DOI:10.1890/10-1044.1

    27. Zeigler, S. L.**, M. C. Neel, L. Oliveira, B. E. Raboy, W. F. Fagan . 2011. Conspecific and Heterospecific Attraction in Assessments of Functional Connectivity. Biodiversity and Conservation. 20:2779-2796. 10.1007/s10531-011-0107-z

    26. Lloyd, M. W.** R. K. Burnett Jr., K. A. M. Engelhardt, M. C. Neel2011. The structure of population genetic diversity in Vallisneria americana in the Chesapeake Bay: Implications for Restoration. Conservation Genetics 12:1269–1285. DOI:10.1007/s10592-011-0228-7

    25. Pettengill, J. B.** and M. C. Neel2011. A sequential approach using genetic and morphological analyses to test species status: The case of United States federally endangered Agalinis acuta (Orobanchaceae)American Journal of Botany 98:859–871. DOI:10.3732/ajb.1000267

    24. Leidner, A. K.†  and M. C. Neel2011. Taxonomic and Geographic Patterns of Decline for Threatened and Endangered Species in the United States. Conservation Biology. 25:716–725. DOI:10.1111/j.1523-1739.2011.01689.x

    23. Pettengill, J. B.** and M. C. Neel2010. An Evaluation of Candidate Plant DNA Barcodes and Assignment Methods for Diagnosing Species in the Genus Agalinis (Orobanchaceae). American Journal of Botany 97:1391–1406.  DOI:10.3732/ajb.0900176

    22. Kennedy, C. M.**, W. F. Fagan, P. P. Marra, and M. C. Neel2010. Landscape Matrix and Species Traits Mediate Responses of Neotropical Resident Birds to Forest Fragmentation in Jamaica. Ecological Monographs 80:651–669.  DOI:10.1890/09-0904.1

    21. Scott, J. M., D. D. Goble, A. Haines, J. A. Wiens, and M. C. Neel2010. Conservation-Reliant Speciesand the Future of Conservation. Conservation Letters 3:91–97.  DOI:10.1111/j.1755-263X.2010.00096.x

    20. Laikre, L, F. W. Allendorf, L. C. Aroner, C. S. Baker, D. P. Gregovich, M. M. Hansen, J. A. Jackson, K. C. Kendall, K. McKelvey, M. C. Neel, I. Olivieri, N. Ryman, M. K. Schwartz, R. Short Bull, J. B. Stetz, D. A.Tallmon, B. L. Taylor, C. D. Vojta, D. M. Waller, R. S. Waples. 2010. Neglect of Genetic Diversity in Implementation the Convention on Biological Diversity. Conservation Biology 24:86–88.  DOI: 10.1111/j.1523-1739.2009.01425.x

    19. Fox, H. E., P. Kareiva, B. Silliman, J. Hitt, D. Lytle, B. S. Halpern, C. V. Hawkes, J. Lawler, M. C. Neel, J. D. Olden, M. A. Schlaepfer, K. Smith, H. Tallis. 2009. Why Do We Fly? Ecologist’s Sins of Emission. Frontiers in Ecology and the Environment 7:294–296. DOI:10.1890/09.WB.019

    18. Pettengill, J. B.**, R. K. Burnett, and M. C. Neel2009. Characterization of 21 Microsatellites Within Agalinis acuta (Orobanchaceae) and Cross-Species Amplification Among Closely Related Taxa. Molecular Ecology Resources 9:1375–1379.

    17. Burnett, R. K.*, M. Lloyd**, and M. C. Neel2009. Development of Eleven Polymorphic Microsatellite Markers in a Macrophyte of Conservation Concern, Vallisneria americana Michaux (Hydrocharitaceae). Molecular Ecology Resources 9:1427–1429. DOI:10.1111/j.1755-0998.2009.02578.x

    16. Pettengill, J. B.**, M. C. Neel2008. Phylogenetic Patterns and Conservation in the Genus Agalinis (Orobanchaceae). BMC Evolutionary Biology 8:264. DOI: 10.1186/1471-2148-8-264

    15. Cummings, M. P., M. C. Neel, and K. L. Shaw. 2008. A Genealogical Approach to Quantifying Lineage Divergence. Evolution. 62:2411–22. DOI:10.1111/j.1558-5646.2008.00442.x

    14. Neel, M. C. 2008. Patch Connectivity and Genetic Diversity Conservation in the Federally Endangered and Narrowly Endemic Plant Species Astragalus albens (Fabaceae). Biological Conservation 141:938–955. DOI:10.1016/j.biocon.2007.12.031

    13. Cushman, S. A., K. McGarigal, and M. C. Neel2008. Parsimony in Landscape Metrics: Strength, Universality, and Consistency. Ecological Indicators 8:691–703. DOI:10.1016/j.ecolind.2007.12.002

    12. Ferrari**, J. T., T. R. Lookingbill, and M. C. Neel2007. Two Measures of Landscape-Graph Connectivity: Assessment Across Gradients in Area and Configuration. Landscape Ecology22:1315–1323. DOI:10.1007/s10980-007-9121-7

    11. Grand, J. M. P. Cummings, A. G. Rebelo, T. H. Ricketts, and M. C. Neel2007. Biased Data Reduce Efficiency and Effectiveness of Conservation Reserve Networks. Ecology Letters 10: 364–374. DOI:10.1111/j.1461-0248.2007.01025.x

    10. Grand, J.**, J. Buonaccorsi, S. A. Cushman**, C. R. Griffin, and M. C. Neel2004. A Multi-Scale Landscape Approach to Predicting Bird and Moth Rarity Hotspots in a Threatened Pitch Pine-Scrub Oak Community. Conservation Biology 18:1063–1077. DOI:10.1111/j.1523-1739.2004.00555.x

    9.   Neel, M. C., K. McGarigal, and S. Cushman. 2004. Behavior of Class-Level Landscape Metrics Across Gradients of Class Aggregation and Area. Landscape Ecology 19: 435–455.  DOI:10.1023/B:LAND.0000030521.19856.cb

    8.   Neel, M. C. and M. P. Cummings. 2004. Section-Level Relationships of North American Agalinis (Orobanchaceae) based on DNA Sequence Analysis of Three Chloroplast Gene Regions. BMC Evolutionary Biology 4:15. DOI:10.1186/1471-2148-4-15

    7.   Neel, M. C., and M. P. Cummings. 2003. Genetic Consequences of Ecological Reserve Design Guidelines: An Empirical Investigation. Conservation Genetics 4: 427–439. DOI:10.1023/A:1024758929728

    6.   Neel, M. C., and N. C. Ellstrand. 2003. Conservation of Genetic Diversity in the Endangered Plant Eriogonum ovalifolium var. vineum (Polygonaceae). Conservation Genetics 4:337–352. DOI:10.1023/A:1024017029933

    5.   Neel, M. C., and M. P. Cummings. 2003. Effectiveness of Conservation Targets in Capturing Genetic Diversity. Conservation Biology 17:219–229. DOI:10.1046/j.1523-1739.2003.01352.x

    4.   Neel, M. C. 2002. Conservation Implications of Reproductive Ecology in the Federally Endangered Plant Agalinis acuta (Scrophulariaceae). American Journal of Botany 89:972-980. DOI: 10.3732/ajb.89.6.972                    

    3.   Neel M. C., J. Ross-Ibarra*, and N. C. Ellstrand. 2001. Implications of Mating Patterns for Conservation of the Endangered Plant Eriogonum ovalifolium var. vineumAmerican Journal of Botany 88:1214–1222.

    2.   Neel, M. C., and N. C. Ellstrand. 2001. Patterns of Allozyme Diversity in the Threatened Plant Erigeron parishii (Asteraceae). American Journal of Botany 88:810–818.

    1.   Neel, M. C., J. Clegg, and N. C. Ellstrand. 1996. Isozyme Variation in Echinocereus engelmannii var. munziiConservation Biology 10:622–631. DOI:10.1046/j.1523-1739.1996.10020622.x