Thursday, August 26, 2010

Battle for the Back Woods II: Herbs, Shrubs, and Grasses

This is part II of our three part post, Battle for the Back Woods, discussing many of the non native invasive plant species that are impacting the natural systems of the Back Woods. Part I discussed non native and invasive vines which top our list of plants threatening our little woods. With part II we take a look at a few non native shrub, herb, and grass species that are in the middle of our list bothersome plants…

In these posts you will see reference to Category I and Category II invasive species. These designations are defined as follows by the Florida Exotic Pest Plant Council (FLEPPC).

Invasive exotic plants are termed Category I invasives when they are altering native plant communities by displacing native species, changing community structures or ecological functions, or hybridizing with natives. This definition does not rely on the economic severity or geographic range of the problem, but on the documented ecological damage caused. Category II invasive exotics have increased in abundance or frequency but have not yet altered Florida plant communities to the extent shown by Category I species. These species may become Category I if ecological damage is demonstrated.

Many of these shrubby, herbaceous, and grassy species are considered serious and difficult to control pests. We place them in the middle of list of bothersome plants because most, with the exception Boston fern and primrosewillow, appear in very limited and so far controllable patches in the woods. Not an all inclusive list, these are our top seven herbs, shrubs, and grasses in descending order from the most pestiferous  in the Back Woods.

Wanted Tuberous Sword Fern Boston fern (Nephrolepis cordifolia), introduced to Florida from the ornamental plant trade, has been a serious problem in the Back Woods. As part of our restoration grant through the EPC of Hillsborough County, we were able to hire an herbicide contractor that helped us put a serious hurt on some fairly significant areas of dense fern populations. But because this Category I species can be persistent, returning from tuberous root systems or germinating from the thousands of spores released from fertile fronds, we have to be vigilant in our follow up control measures. Hand pulling and herbiciding are the primary means of control. Volunteers are welcome always to help us hand pull this readily identifiable species.

DSCN0078Peruvian primrosewillow (Ludwigia peruviana), an obligate wetland species, has found a foothold in many of the wet areas of the Back Woods. Primrosewillow has beautiful four petalled yellow blossoms nearly year round. Unfortunately the flowers of this Category I species are followed by large angled capsules that can sow the seed bank with millions (yes millions) of seeds. The plants themselves are pretty persistent even after application of herbicides. We cut and stump treat to make a dent in the population yearly. I am not sure we will ever completely eradicate it from the wetlands.

DSCN0064 Caesar weed  (Urena lobata) can be found most everywhere that is not overly wet in the Back Woods. While taking measures to control a wildfire that occurred in the Back Woods last year, the DOF put a plow line in around the sinkhole complex. Every inch of that disturbed bare soil erupted Caesar weed. Only a Category II species, Caesar weed is still very pioneering meaning it can rapidly fill any new openings or disturbed areas out competing other species for growing space. Volunteers have helped us hand pull thousands of square feet of Caesar weed in an effort to control its spread. Caesar weed produces fruit with hooked barbs that cling to the fur of passing animals or to just about any clothing as well as human hair. Part of our continuing challenge is to treat this species before it sets fruit and to take care not to spread the fruit ourselves.

natalgrass2 Rose Natal grass (Melinis repens) is a Category I invasive species that poses a threat to our sandhill habitats in the Back Woods. Adapted to arid conditions like those in the sandhill, this grass can displace the native grasses that are an important food source for our threatened gopher tortoises. Natal grass can spread quickly into disturbed areas making it particularly challenging for us as we try to thin the oak canopy around the existing sandhill and open up/expand the sandhill habitats. Hand pulling this grass appears to be the most effective form of control in the Back Woods. But it is often difficult for volunteers (and me too) to distinguish this plant from other grasses when not in bloom.

Lantana_camara4 Lantana (Lantana camara), a very popular and attractive ornamental, has been introduced worldwide from its origin in the West Indies. Found almost everywhere in Florida, Lantana camara is capable of hybridizing with our at least one of our three native  lantanas (Lantana depressa) threatening the genetic integrity of this endangered species and making control of the non native more difficult. This Category I invasive species is spread by animals and birds relocating the fruit/seed. Repeated treatment of individual plants and new recruits are key to its control in the Back Woods. If you plant non native ornamental hybrids of lantana, look for sterile varieties or better yet plant the common native buttonsage (Lantana involucrata) instead. Check out this very interesting article on distinguishing native and non native lantana species.

Schinus_terebinthifolia10 Brazilian pepper (Schinus terebinthifolius) is not only a Category I invasive species but, finds itself listed on the 100 of the World's Worst Invasive Alien Species on the Global Invasive Species Database. Brazilian pepper could be the picture beside the definition of a Category I invasive species. It forms dense monocultures that suppress all other plant growth through sheer biomass as well as allelopathic chemicals. Cutting and stump treating the plants has worked so far but potential for reintroduction from birds or mammals from nearby sources is always likely. Fortunately for us, Brazilian pepper is spotty in just a couple of areas along the wetland margins. This ecosystem altering invasive species has actually become a notable component in honey production in Florida, providing nectar for honey bees in the winter months and producing a locally popular (one of my favorites) peppery honey.

cogongrassCogongrass  (Imperata cylindrica) is a Category I species. It is so bad… it has its own website! This nasty found its way to the US South as a packing material, forage crop, and ornamental. Cogon grass forms dense monocultures that exclude other plants and may even inhibit ground dwelling/nesting animal species. Cogon grass is adapted to survive in an environment with fire. Unfortunately, it can also alter native fire regimes by burning more intensely than than native grass species damaging otherwise fire resistant/tolerant plants and soils. Fortunately for us, cogongrass has only cropped up in a spot or two. Pulling and herbiciding has controlled it so far. There is the potential it could be reintroduced from seeds blowing in from outside sources. Cogongrass is easy to id when in bloom by its long cylindrical fluffy seed head or by its leaf blades which have a finely serrated edge (feel not see) and the noticeably off center midrib (see the photo).

 NEXT WEEKNon native invasive tree species inhabit a few pockets of the Back Woods but have been the least of our concern and so far have been fairly easily controlled with herbicide and a chainsaw ;-).

Some of the common names I use may seem unfamiliar or appear to be a variation of a more familiar common name for the plants discussed. I try to use the common names as well as the currently listed scientific name as listed on the Atlas of Florida Vascular Plants as a convention to keep our naming and references consistent in this blog.


uncle sam WE WANT YOU: If you are looking for a great work out (pulling up plants and wielding loppers) we are always looking for intrepid VOLUNTEERS to help us out in our battle against invasives. Current opportunities M-F 7am-4pm.

Tuesday, August 24, 2010

This Week in the Woods

DSCN2513 Water levels in the wetlands and sinkholes have fluctuated widely over the past week with the extreme heat and evaporation during the day followed by evening thunderstorms. Despite all the rain, mosquitoes populations are still notably quite low likely from the  recent county wide aerial spraying.  This nice hatch out of leaf footed bugs on dotted smartweed was captured this past week in the very ephemeral wetlands near the sinkhole.

DSCN2520 After a recent question to this blog about Six-lined Racerunners (Cnemidophorus sexlineatus) I have been on the look out to capture some new pictures. So far most of these zippy little racerunners have lived up to their name and eluded me…they are just too wary and too darn fast! I snapped this very sizeable lizard in some marginal habitat near the more open sandhill. I estimated it was around 8 inches in length which puts it close to their top size of around 9 inches. Plans for a tripod, umbrella and a day of patience camped out in the sandhill are in the works to get some better shots to share with our Back Woods friends.

 DSCN2315It is a great time to take walk through the sandhill. It literally is awash in the bright golden yellow blossoms of the partridge pea! Then top that off with some bright yellow sulpher butterflies flitting between each partridge pea plant laying their eggs and bees of all sorts trying to visit every flower with pollen sacks so loaded they can barely fly. It is quite a site!

DSCN2524 The gopher tortoise are really active this time of year as well…new burrows of all sizes, including some itty bitty ones, are popping up in the western sandhill so watch your step. A pair of larger tortoises in one burrow leads us to hope we will have more little ones in the spring. Please be sure to give the aprons of any burrows a wide birth, female gopher tortoise often lay their eggs in the apron or close by.


DSCN2525 And a set of young quadruplets are busy tearing up the woods on the south side of the property…fresh burrows with a rounded entrance (gopher tortoise burrow entrances are oval) are a good indication of an armadillo. With a delightfully descriptive scientific name…Dasypus novemcinctus…roughly translated to something like rabbit or hare with nine girdles (oh, my)…we find it hard not to like these curious critters. Unfortunately, they are not native to Florida. They made their way here from the Mexico and Texas as land development and modification of rivers made their travels easier and made their way from south Florida via introduction from the pet and novelty trade. These omnivorous mammals will consume most any invertebrate they come across. Of concern to us is that they are a documented as predator of gopher tortoise eggs. So far it seems these four prefer the insect rich litter beneath the oak hammock to the exposed sun baked sandhill.

Send us your pictures of your favorite things in the Back Woods and we’ll share them in our blog or post them on Facebook!

Wednesday, August 18, 2010

Battle for the Back Woods I: Invasive Vines

DIBU_9-2-08_labeled We have two great challenges to rehabilitating and maintaining the ecosystems in the Back Woods…controlling non native invasive plant species and the limitations on using prescribed fire (another post for the future). Our battle with one invasive plant species, air potato (Dioscorea bulbifera), has been the subject of many blog posts in past. This time in three parts we will take a  broader look  at the topic of invasives in the Back Woods. Part I covers invasive vine species, part II herbs and shrubs, and part III trees.

In these posts you will see reference to Category I and Category II invasive species. These designations are defined as follows by the Florida Exotic Pest Plant Council (FLEPPC).

Invasive exotic plants are termed Category I invasives when they are altering native plant communities by displacing native species, changing community structures or ecological functions, or hybridizing with natives. This definition does not rely on the economic severity or geographic range of the problem, but on the documented ecological damage caused. Category II invasive exotics have increased in abundance or frequency but have not yet altered Florida plant communities to the extent shown by Category I species. These species may become Category I if ecological damage is demonstrated.

The battle in the Back Woods against non native invasive plant species is ongoing. Even with extensive professional contractual spraying, hundreds of volunteer hours of mechanical removal, and countless additional follow up herbicide treatments many non native invasive plant species still have a foothold in the Back Woods.  Many of these invasive species may be eliminated and reintroductions more easily eradicated but, a few key species will likely be a management concern for years to come.  Invasive species compete with our native species for growing space and resources. Some can actually change the ecological function of the forest affecting hydrology and fire frequency. Controlling these species is a critical component in our restoration efforts. A common but interesting side effect of some of the treatments has been the release of other species previously less noticeable. Treating and removing smothering masses of air potato as well native grape vine (Vitis rotundifolia) opens up the canopy allowing more light and water to the ground. This has had the desired effect of opening up the growing space for many native herbs and shrubs but also released masses of another invasive species, the skunk vine (Paederia foetida), everywhere. This vine is but one of many of our nemeses in the battle for the Back Woods.

Vines top our list of least welcome invaders. Without fire as a disturbance to interrupt their growth; unchecked they can quickly cover cleared areas, smother midstory vegetation, and climb into the canopy of trees. This growth not only alters the structure of the vegetation of the forest, it increases the possibility of tree loss should we have a wildfire. Vines climbing into the canopy are termed “ladder fuels” which can carry fire into the canopy and destroy otherwise fire tolerant tree species such as longleaf pine (Pinus palustris.) Some of our viney invaders include air potato (Dioscorea bulbifera), skunk vine (Paederia foetida) , and Japanese climbing fern (Lygodium japonicum).

  • DSCN8151 Air potato is a very persistent species. This Category I invasive species produces aerial tubers call bulbils along the vines. Bulbils, some no larger than the end of your fingernail, can be produced by the hundreds and each one can produce a new vine unless removed or destroyed. Removing or treating the vines and picking up and disposing of bulbils are key to controlling the vine. Fortunately for us, reintroduction of air potato is usually limited to bulbils floating in on water or vines encroaching from neighboring properties. Water does not come into the property from other sources so, if we can control the vine at our borders we may eventually be able to significantly curtail air potato growth in the Back Woods.
  • DSCN4829Skunk vine was introduced to Florida at the turn of the 20th century as a potential fiber crop (the stem is very rubbery and strong) and quickly escaped cultivation to become a Category I invasive species. This vine was spotty through out our little woods and only found extensively in only a couple of places near the wetland. As noted earlier, after some significant removal of other competing vines the skunk vine started popping up in more places. It can regenerate from broken stems and it spreads readily from seed. We are tackling this invasive with herbicide and mechanical removal and have to take great care not to spread it ourselves in the removal process. Those tough rubbery stems also make for very difficult removal from the canopy. It may be possible for skunk vine seed to be carried in by birds which can be a source of continued reintroduction.
  • DSCN8069 Japanese climbing fern, a Category I invasive species, found its way to Florida in the 1930’s as an ornamental plant. Established first in the northern parts of the state it has been making its way southward. [A related fern species the old world climbing fern (Lygodium microphyllum) was introduced in the south and is progressing northwards. It is considered potentially the most threatening species to Florida’s natural areas. A battle line has been drawn at Interstate 4 to prevent the old world climbing fern from invading the sensitive ecosystems of the Green Swamp (the source of four of our local rivers and drinking waters) and from moving further north.] Japanese climbing fern can grow just about anywhere but we find it mainly along the margins of the wetlands and wetter flatwoods areas. With frond that can grow up to 90 feet this fern can easily reach the top of the pine canopy and shade out vegetation below. This species is only spotty throughout the  Back Woods. Key to its control is to eliminate it before spores are produced in the fall. Spores spread from even great distances may present a continued source of reintroduction.
  • DSCN0117 One native species, muscadine or wild grape (Vitis rotundifolia), has a place on our nuisance species list. Even this native species can become problematic. Unregulated by any disturbance such as fire, the growth of grape vines can have similar ecologically altering effects as non native vines. You may notice that we use many of the same control measures for grape vines that we do for the non native species. Rest assured though, the grape has a place in our forest ecosystems. You find a sign describing the plant along the trail at a particularly large example of their woody vines…and of course in the midst of summer you find me grazing on their wonderful fruit!

Next week… in the middle of our list of bothersome plants are a few non native invasive herbs and shrubs.

If you are looking for a great work out we are always looking for intrepid volunteers to help out in our battle against invasives.

Friday, August 6, 2010

Bugs Abound

Bugs abound in the Back Woods this summer! If you are a fan of most things Arthropoda, you might want to spend and afternoon hitting the trails, scouring the foliage, and sifting through the leaf litter in the Back Woods.

Nectaring butterflies have been the hot commodity at the Buttonbush Pond during the spring/summer bloom. The egg laying action is about to pick up in the sandhill where the partridge pea (Chamaecrista fasciculata) will prove irresistible to a variety of sulphur butterflies. The sandhill is where you will also find our very own example of Sisyphus in the rainbow scarab (Phanaeus vindex) diligently rolling up and and storing whatever piles of poo it comes across. Florida harvester ants (Pogonomyrmex badius), forever on the march, find their home in the sandhill as well.

The cicadas are most definitely turning up the volume through out the woods…look for their molts at the top of shrubs and dead  branches. Keep your focus ahead on the trails lest you walk right into the web of a tiny spiny orb weaver (Gasteracantha cancriformis) or a not so tiny golden silk spider (Nephila clavipes). One of my favorites, the green lynx spider (Peucetia viridans), looks like green glass. They don't spin a web but rather stalk the foliage for their unsuspecting prey.

Deep in the leaf litter you will likely come across all sorts of things including the real Florida palmetto bug…the Florida woods cockroach (Eurycotis floridana). These nearly wingless roaches are not considered household pests preferring the rich bounty of the outdoors to your pantry. Disturb them and they emit a very noticeable odor something like almonds or sweet amaretto.

Once you have had your buggy fill of the Back Woods don’t forget to stop off in the Bioworks Butterfly Garden for an up close look at the metamorphosis of Florida native butterflies.

Of course, the woods would not be the woods without our very own population of mosquitoes. So, use good sense as you would in any outdoor area this time of year, cover up and wear your insect repellant.


Check out the Animal Species tab at the top of the page for a listing of more of the insects found in the Back Woods