The Ecology and Paleoecology group is located within the Department of Geography and Environmental Engineering at the Johns Hopkins University. We seek to understand how climates, landscapes, and plant communities change over time through the use of environmental proxies like preserved sediment, pollen, and microorganisms.
Areas of Study
Relationships between plant species and environmental conditions
- Map of the natural vegetation of Maryland
The forests of Maryland were classified into 18 distinct communities based on the presence of indicator species and mapped at a scale of 1:250,000. The forest patterns coincide with soils and geology that have similar hydrologic properties. Thus one community, designated the blackjack oak-post oak-chestnut oak occurs on the three driest substrates in the state: serpentine, with no soil formation; gravels with no water-holding ability; and fragipans where an impervious layer lies close to the surface. The data used for drawing the boundaries of the map were presence and absence of species along random transects throughout the state including all roads, trails and other traverses. The composition of the forests was derived from 1270 randomly distributed 400 and 625 m² plots where all stems >2cm at diameter breast height were identified, counted and measured. In addition, saplings in one-quarter of each plot were counted and identified. Principal component analysis was used to identify the clusters. The organization of species into clusters was investigated by running principal component analyses of subsets of the data based on size, and showed that the different clusters or communities were not evident until stems had reached from 10 to 15 cm dbh. Some species were organized into groups earlier than others. The emergence of patterns is likely related to mortality of young trees whose root physiology is incompatible with substrate hydrology.
- Brush, G. S., C. Lenk and J. Smith. 1980. The natural forests of Maryland: an explanation of the vegetation map of Maryland. Ecological Monographs 50 (1): 77-92 plus map (click to download map as 11.4MB PDF)
- Brush, G. S. 1982. Environmental analysis of forest patterns. American Scientist 70: 18-25.
- Vegetation of the Gwynns Falls watershed, Baltimore City
Paleoecology of the Chesapeake Bay Ecosystem
- Climate history
- Anthropogenic history
Biological and physical controls of pollen entrainment into the atmosphere and patterns of dispersion