The study was divided into three focal areas:
- A qualitative assessment of the natural features in the terrestrial habitats at the preserve, including the compilation of historical records.
- The establishment of long term vegetation monitoring plots and transects and initial data collection.
- A geographic information system based assessment of invasive plant species at the preserve.
The qualitative assessment focused on vascular plants and birds, as they are easily censused and meaningful indicators of habitat quality. A total of 455 plant species were documented. More than 70 percent are native species, and 119 are newly reported at the preserve. The dominant tree species in the forest is wild black cherry, though white and black oak are prominent in the canopy, and red oak and pignut hickory are also common. Collectively, the invasive shrubs glossy and common buckthorn and bush honeysuckle dominate 60 percent of the forest understory, resulting in low understory diversity. Between the years of 1976 and 2009, 117 bird species were recorded at Asylum Lake Preserve. The study done in 2009 observed two previously undocumented species, the Henslow's Sparrow and Pine Warbler.
Overall, the natural features of Asylum Lake Preserve are highly degraded through many years of human occupation and the effects of urbanization. Small pockets of valuable habitat persist and with proper restoration practices, the ecological health of Asylum Lake Preserve can be improved.
Common invasive vegetation at Asylum Lake
Bush honeysuckle (Lonicera maackii) —native to parts of Asia, this plant was planted in the United States to try to control erosion. However, the plant creates a threat of choking out diversity in its non-native ecosystem. The bush honeysuckle produces red berries that are slightly poisonous.
Glossy buckthorn (Frangula anlnus)—The glossy buckthorn is found in Eurasia, and at one time, was commonly planted in the United States as a hedge. But this plant is very invasive, and therefore dangerous to the Asylum Lake ecosystem. Its leaves come out early in the spring and stay until late fall, shading out the surrounding native plants.
Garlic mustard (Alliaria petiolata)—native to Europe, this plant was introduced in the 1800s for use in food and medicine. Garlic mustard forms dense stands that can shade out native plants and also produce chemicals that inhibit the seed production of other plants. It is recognizable by the garlic smell that it gives of when the plant is crushed.