A Review of Invasive Species Commonly Found in North Florida’s Hydric Hammock Communities
Julie Baniszewski, University of Florida, Gainesville, FL 32611
Florida is a welcoming habitat for many invasive species. In an ongoing battle to keep invading species at bay, it is important to educate others on identifying these opportunistic plants. By creating an easily accessible website that includes identifying pictures and descriptions of these invasive plants, management strategies and alternative native plants that can be planted in landscapes, control of these invasive species will become more achievable. Furthermore, other resources will be made available through this website for further information on the hydric hammock community, invasive species in general and each listed invasive plant described on the website. These resources will provide interactive maps of locations of the plants, extension services and other valuable resources in controlling plants.
Research and identification of invasive plant species specific to the hydric hammock natural community in North Florida will be beneficial in educating the community on the hazards posed by allowing these non-native species to establish. Experience and a better understanding of the hydric hammock natural community will be provided as well as common invasive species found in this habitat, their history, identification, impact and management strategies.
Invasive Species: Why they are bad
Invasive species are non-native, but pose a greater threat because they are those plants which have severely impacted a different community negatively (Demers et al. 2012). Often invasive plants are spared from the factors that keep them under control in their natural habitat when they invade the new habitat. These control factors often include predation, disease, parasites or other competition (Demers et al. 2012). There are various degrees of severity that these non-native plants can impose when introduced into a new environment. “Invasive” is a more extreme term applied to plants that grow rapidly, spread throughout an area easily and become established (Demers et al. 2012). This thriving behavior impacts the community by outcompeting other natural plants, disrupting food sources for wildlife and altering ecosystems altogether at times.
Non-native plants in Florida make up an estimated 30% of the 4,000 species known to exist in the state (Demers et al. 2012). Invasive plants that interfere in agriculture are termed “noxious weeds” and combined with other natural management efforts, can cost billions of dollars to implement management efforts and in general monetary losses (Demers et al. 2012). In addition to financial loss, invasive plants can reduce species that are endangered or threatened, reduce community biodiversity and habitat loss for insects and wildlife in addition to other plant species (Demers et al. 2012). Communities can then be completely altered and impacted in other ways such as fire intensity or frequency, seed dispersal, pollination, hybridizations, and other interactions in a community. Because of these impacts and the detrimental alterations that invasive species may induce, it is important to understand these species and management strategies to control them. Often tracing the invading species back to its own native range will identify how the plant was introduced. Control methods including biological control, such as predators or parasites, may also be traced back from the invading plant’s origin. Other methods of control may also include mechanical or chemical techniques.
There are general practices that can be applied to invasive plants such as preventing further spread or removing established plants. Invasive plants thrive in disturbed areas because they have a chance to outcompete native plants. Therefore, one easiest and most beneficial ways of limiting invasive plants from a natural community is to allow the natural biodiversity to proliferate. Preventative methods are often combined with cultural methods and include the timing of removal or spraying of herbicides to do the greatest damage to the plant and prevent spreading of seeds. Cleaning equipment used in landscaping and preventing dispersal of seeds is also beneficial in limiting the spread of introduced nonnative plants. Chemical sprays can work well to kill many invasive species, but herbicides are not often specific to a plant and therefore need to be carefully applied to kill only the targeted plant. In addition, many invasive species have underground growth such as tubers or rhizomes, or may have already seeded. Thus combining cultural and chemical methods specific to a certain species can be much more effective. This may be as simple as applying an herbicide at a certain time of the year before seeds are produced or by re-applying to the plant to ensure the entire plant is dead before removing it.
Specific to Florida, this website is a good source of general information relating to invasive species, their habitats and further information of some specific invasive species: http://floridasnature.com/exotic1.html .
This website is a great database to look at worldwide invasive species. It is very in depth and has several search options including location, habitat, organism type or by taxonomic classification. http://www.issg.org/database/species/search.asp?st=100ss&fr=1&str=&lang=EN
Florida’s List of current Category I and Category II invasive plant species. This list also provides to links for further information on the plant species. https://www.fleppc.org/list/list.htm
The USDA has a site with information on invasive species (by state) as well as other plants that are threatened, endangered, etc. They provide links for the plant species for further information and have a general list that includes the common name, scientific name, noxious status for the state listed under and its native status. http://plants.usda.gov/java/noxious?rptType=State&sort=status&statefips=12
The IFAS Extension for University of Florida has designed a great website with tons of information about aquatic and invasive plants. Many of these plants are accompanied by a brief description, pictures and ID pages and printouts. http://plants.ifas.ufl.edu/
This website has several tabs with subsections of invasive plants of the United States such as “Aquatics” or “Grasses” and makes searching for a particular type of invasive very easy. It has great references, pictures and descriptions for each invasive species listed – and there are many of them! It also features aEDDMapS Distribution of each invasive plant. http://www.invasiveplantatlas.org/index.html
NPS put together fact sheets for invasive plants and categorizes plants based on the type (herb, vine, tree, etc.). This is a great nation-wide site, including invasives not limited to Florida. https://www.nps.gov/index.htm
The University of South Florida has an online Atlas of Florida Vascular Plants, which is a great way to look up any plant of interest, including invasive species. It will also show distribution by county where a specimen has been collected. The site can be accessed via http://www.florida.plantatlas.usf.edu/Default.aspx
There is an incredibly informational mobile field guide that is available. Searches for plants can be done by scientific names, common names or filter searches by categories that the plant may be in. http://www.plantatlas.usf.edu/flip/
Just as the name implies, a hydric hammock is a natural community that is frequently inundated for short periods and the dominant vegetation are hardwood species such as oaks. As a forested wetland, one key characteristic that sets the hydric hammock apart from other forested wetlands is its shorter hydroperiod. Hydric hammocks have a hydroperiod of up to 60 days per year, which can be compared to a cypress or tupelo dominant wetland which have longer hydroperiods. Hydroperiods strongly influence species composition. Although some cypress or tupelo species may be present, due to the shorter hydroperiod, hydric hammocks are dominated by hardwoods (Hydric Hammock 2010). Besides hardwoods, sabal palmetto (sabal palms) are also a dominating species (Wetland Communities: Hydric Hammocks).
Soils are moist, poorly drained and contain limestone (Hydric Hammock 2010). Moisture in the soil accumulates from seepage, seasonal hydrology or nearby river floods (Vince et al. 1989). Soils can be acidic or alkaline, but have little organic matter (Vince et al. 1989). The hydric hammock community is not fire dependent. Fires may occur on an occasional to rare basis and are often influenced by neighboring communities (Hydric Hammock 2010).
The range of hydric hammocks is restricted to Florida and Georgia with the most commonly found locations in Central and North Florida (Vince et al. 1989, Hydric Hammock 2010). As hydric hammocks lay flat and on low, wet sites, they’re often bordered by mesic hammocks or upland hardwood forests which occur if there is an upland grade in the topography. A key difference in mesic hammocks is that they have more southern magnolia, pignut hickory and saw palmetto. Two variations of the hydric hammock are the coastal hydric hammock and the prairie hydric hammock. The coastal community borders salt marsh and coastal communities and therefore experiences higher salinity. Vegetation depends on the salinity of the community. High salinity, often associated with coastal locations, leads to a community with mostly cabbage palms, live oak and red cedar. (Hydric Hammock 2010). The prairie hydric hammock borders marshes and is also dominated by cabbage palm, and sometimes can contain live oak and red cedar. However, a lower salinity, often associated with the prairie hydric hammock allows species such as red cedar, live oak and swamp laurel oak to dominate as well.
Common Hydric Hammock Species
|Common Canopy Species||Common Ground Cover Species|
|Scientific Name||Common Name||Scientific Name||Common Name|
|Acer rubrum||red maple||Aesculus pavia||red buckeye
|Celtis laevigata||sugar-berry; hackberry||Arisaema spp.||jack-in-the-pulpit; green-dragon|
|Diospyros virginiana||common persimmon||Berchemia scandens||rattan vine
|Fraxinus americana||white ash||Carpinus caroliniana||American hornbeam
|Fraxinus profunda||pumpkin ash||Chasmanthium latifolium||spangle grass
|Gleditsia aquatica||water-locust||Chasmanthium sessiliflorum||longleaf chasmanthium|
|Gleditsia triacanthos||honey-locust||Chasmanthium spp.||spanglegrass
|Ilex cassine||dahoon holly||Crataegus marshallii||parsley haw
|Ilex opaca||American holly||Crataegus viridis||green haw
|Juniperus virginiana||eastern red cedar||Decumaria barbara||climbing hydrangea
|Liquidambar styraciflua||sweetgum||Elephantopus nudatus||purple elephant’s foot
|Liriodendron tulipifera||tulip tree||Elytraria caroliniensis||Carolina scaly-stem
|Magnolia grandiflora||southern magnolia||Itea virginica||Virginia willow|
|Magnolia virginiana var. australis||sweetbay magnolia||Lyonia lucida||fetter-bush
|Morus rubra||red mulberry||Mitchella repens||partridge berry
|Nyssa sylvatica var. biflora||swamp tupelo||Osmunda cinnamomea||cinnamon fern
|Persea palustris||swamp bay||Rhapidophyllum hystrix||needle palm|
|Pinus ellottii||slash pine||Rhynchospora spp.||beakrush
|Pinus teada||loblolly pine||Sabal minor||dwarf palmetto|
|Quercus laurifolia||laurel oak||Viburnum dentatum||arrow-wood|
|Quercus michauxii||swamp chestnut oak||Viburnum obovatum||Walter viburnum|
|Quercus nigra||water oak||Woodwardia areolata||chainfern|
|Quercus virginiana||live oak||Woodwardia virginica||chainfern|
|Sabal palmetto||cabbage palm|
|Tilia americana||American basswood|
|Ulmus americana var. floridana||American elm|
Source: Wetland Communities: Hydric Hammocks
The website to Florida’s Department of Environmental Protection has a website with Hydric Hammocks and their information in addition to many other communities, projects and information about wetlands, water systems and policies. For the hydric hammock section, they include commonly found plant species, which is helpful in identifying a hydric hammock. http://www.dep.state.fl.us/water/wetlands/delineation/wetcomm/hydham.htm
Florida Natural Areas Inventory is a great site to find abundant information on any natural community in the state. They provide links to PDF formatted documents for each community and do a great job at comparing closely related communities so that you can easily tell the difference between a Hydric Hammock and a Bottomland Forest or any other community. http://www.fnai.org/natcom_accounts.cfm
Turkey Creek Hammock is a local hydric hammock near Gainesville, Florida. The following links provide more information on the community.
Ardisia crenata (Coral ardisia, Scratchthroat)
Broussonetia papyrifera (Paper mulberry)
Dioscorea bulbifera L. (Air-potato)
Imperata cylindrica (Cogongrass)
Lantana camara (Lantana)
Leucaena leucocephala (Lead tree)
Lonicera japonica (Japanese honeysuckle)
Lygodium japonicum (Japanese climbing fern)
Nandina domestica (heavenly bamboo)
Nephrolepis cordifolia (Sword fern)
Paederia foetida (Skunk vine)
Invasive species are problematic, especially in a diverse environment such as Florida. They displace and compete with native plants and disrupt ecosystems. Invasive plants often thrive in disturbed areas due to the reduced natural biodiversity and open soil in which they can easily germinate and establish. This is a concern because native plant species are often unable to re-grow there. Furthermore, after an invasive plant becomes established and thrives, it deprives light, nutrients, and water to natural species. In some cases of climbing vines, the weight of the invading plant alone can kill native trees and shrubs. Additionally, in some species, the invading species may hybridize with native species and reduce the genetic pool of natural Florida plants. This is becoming the case for lantana. Invasive species are also typically free of natural enemies, which were often present in their native range, but may not have been moved with the plant. This further allows these introduced species to thrive in the introduced range.
Management strategies are often easy and are most effective when you know a more about the plant you are trying to remove, such as when they seed to spray before seeds develop. Other simple management strategies include cleaning off equipment that was used in landscaping before moving the equipment to prevent the spread of seeds or vegetative remains. Many chemicals, such as Roundup, can be applied directly to invasive plants to kill them.
Finally, educating people on which species are invasive can benefit everyone. Many invasive species are sold in nurseries and can be easily replaced with similar native species. Plants that have been removed should be replaced to maintain some natural biodiversity to prevent reinfestation of the invasive plant.
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Hydric Hammock.2010. FNAI – Guide to the Natural Communities of Florida: 2010 Edition. http://www.fnai.org/PDF/NC/Hydric_Hammock_Final_2010.pdf
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Pemberton, Robert. 2002. Old-World climbing fern. In: Van Driesche, R. et al. (eds.) Biological Control of Invasive Plants in the Eastern United States. USDA Forest Service Publication FHTET-2002-04.413 pp.
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Vince, S.W., S.R. Humphrey, and R.W. Simons. 1989. The ecology of hydric hammocks: a community profile. Biological Report.85(7.26).United States Fish and Wildlife Service, Washington, DC.
Wetland Communities: Hydric Hammocks. Update September 21, 2011. Florida Department of Environmental Protection. Tallahassee, FL. http://www.dep.state.fl.us/water/wetlands/delineation/wetcomm/hydham.htm
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