Save Florida's Bromeliads

Some of Florida's bromeliads are on Florida's Endangered Species List and it is illegal to handle them
without permission. For more information, visit FDACS Endangered Plants Page.

Method of Mapping Five Natural Areas in Florida
2001-2005

This method was designed to monitor bromeliad populations in south Florida and the invasive bromeliad-eating weevil, Metamasius callizona (Chevrolat) that arrived in Florida in 1989 and that has since been attacking Florida’s native bromeliads.

Bromeliads were monitored in five Natural Areas in south Florida: Myakka River State Park (MRSP), Loxahatchee National Wildlife Refuge (LNWR), Highlands Hammock State Park (HHSP), Fakahatchee Strand Preserve State Park (FSSP), and St. Sebastian Buffer Preserve State Park (SSSP) beginning in June 2001 and ending in June 2005. Myakka River State Park was chosen as the primary research site because it had a large bromeliad community which included both Tillandsia fasciculata Swartz and T. utriculata L. (two of the large bromeliad species that have a wide range in south Florida and that have been under heavy attack by M. callizona) and because M. callizona had only recently been found in the park (in September 2000, one year before the start of this research; Frank 1996b). The other four Natural Areas were selected in order to incorporate localities with different species of bromeliads into the study and based on the availability of volunteers to collect data.

Data were collected from demarcated Sections that were defined using a multi-tiered method. Tiers were defined by bromeliad habitat and Bromeliad Host density. Bromeliad Hosts are the substrates upon which the bromeliads grow; usually a host was a tree, however some were vines or stumps, and a few of the bromeliads grew terrestrially. The tiers, by decreasing size, were called Natural Area, Region, Area, Section, and Bromeliad Host (see Table A-1 in Appendix A).

Sections were mapped using a baseline from which to triangulate trees, Bromeliad Hosts, and other landmarks. These numbers were transcribed to grid-mapping paper using a compass and straight-edge. The maps were used to define the boundaries for data collection and to calculate the area monitored.

Materials for mapping a Section included two 91 m surveyor tapes; one 1.5 m stick with a small portion sanded level on the back end, with 2 pegs stuck in to which a compass could be affixed; a compass with holes drilled in it to fit the pegs on the stick; surveyor flags to mark Bromeliad Hosts; stakes to hold down surveyor tapes; and a log book for recording data.

To map a Section, a baseline was laid along some definable path (an actual path or road, or a chosen stretch in a stand of trees). Compass bearings were taken for the baseline. The objects to be mapped (the trees, including the Bromeliad Hosts and other obvious, persistent landmarks) were positioned by triangulating each object, using at least 2 compass bearings from the baseline. Rough estimations show this method of mapping is accurate to within approximately a third of a meter; the further the objects were from the baseline, the greater the loss in accuracy. Information recorded for each object included compass bearing and baseline reading for each line of sighting, the type (hardwood, pine or palm) and size of the tree (or other object); and whether it was a Bromeliad Host.

Two data sets were collected monthly within the demarcated Sections: 1) Demographic data on a population of selected living bromeliads growing in the canopy; and 2) Collection of fallen dead bromeliads within the demarcated Sections.

For data set 1, a portion of the Bromeliad Hosts within each Section was randomly selected and the bromeliads on these Bromeliad Hosts made up the population of bromeliads being monitored. Each Bromeliad Host was sketched from a particular spot (indicated on the Section map), and its resident bromeliads were added in the sketch for relocation purposes. Each bromeliad was assigned a unique number and identified to species (if possible; T. utriculata and T. fasciculata are difficult to distinguish when they are small and medium-size plants). Data collection included class-size (small, medium or large). Class sizes were based on longest leaf length. Botanists have traditionally used leaf area and dry weight to measure size of plants. The disadvantage of these measurements is that they require killing the plant. Length of longest leaf was developed as a non-lethal method for measuring T. utriculata and was related by regression to water-impounding capacity of leaf axils (Frank and Curtis 1981). Length of longest leaf was measured together with dry weight and leaf area by Frank et al. (2004). Size classifications vary according to species; Table C-1 in Appendix C gives the size classifications used in this study for species included.

Health ratings were assigned monthly for the selected bromeliads. The health rating was an indicator of the condition of the bromeliad’s health and was based on assessment of certain outwardly physical characteristics, such as the color and fullness of the leaves and physical injuries that were visible. Health ratings ranged from 3.0 (thriving and well; no injuries, discoloration, or dehydrated leaves) to 1.0 (completely dead; no green left remaining on the plant). The 3.0 to 1.0 range was divided into four quarters: 3.0 to 2.5 (healthy); 2.4 to 2.0 (moderately stressed); 1.9 to 1.5 (heavily stressed); and 1.4 to 1.0 (seriously stressed; ultimately ending in death). Table D-1 (Appendix D) outlines these four quarters and the characteristics that indicate where a bromeliad would be categorized.

Bromeliads were chosen based on apparency; if a Bromeliad Host was covered with bromeliads, this was noted, but only the most obvious were mapped. When a selected bromeliad died or disappeared, evidence would be sought to determine the cause of death or disappearance. To replace dead or lost bromeliads, Bromeliad Hosts were updated and replaced every 6 months. If all of the bromeliads being monitored on a Bromeliad Host died or disappeared, then the Bromeliad Host was examined thoroughly for any remaining bromeliads, and these were monitored; if there were no more bromeliads available, then a new Bromeliad Host in the Section was randomly selected to take its place.

For data set 2, the Section maps defined the area on the ground to be searched for dead bromeliads that had fallen from the canopy. The bromeliads were examined for cause of death. If weevil specimens or pupal chambers were present, they were collected. An attempt would be made to rear larvae and pupae to adulthood because it is difficult to distinguish M. callizona larvae and pupae from that of Florida’s native bromeliad-eating weevil, M. mosieri Barber.

MRSP, the primary research site, was mapped first; subsequently, five new Areas were added to existing Regions, and 1 new Region was added. The other four Natural Areas were included later than June 2001 and ended before June 2005. Only LNWR had a new Area added after its initial mapping. MRSP data were collected by me. The other Natural Areas were mapped by me, but monitored by volunteers using my method.

Table B-1, in Appendix B, shows the total hectarage mapped for each Natural Area, the mapping and monitoring schedules, and the bromeliad species that were monitored. The five Natural Areas that were monitored represented different habitats and bromeliad communities. MRSP was monitored monthly for 49 months. Total land area monitored in MRSP covered 2.98 hectares. Seventeen Areas were mapped in hardwood forests, hammocks and mixed hardwood/palm forests. Seven hundred thirty-nine bromeliads were selected for monitoring; the population was composed of approximately 72% Tillandsia fasciculata Swartz, 27% T. utriculata L., and 1% T. balbisiana Schultes.

LNWR was monitored for 28 months until monitoring was interrupted by hurricane activity in August and September 2004. Total land area monitored was 0.05 hectares and included 115 selected bromeliads. Three areas were mapped, one in the interior of a cypress dome and two on the edge of the cypress dome. The bromeliad population was approximately 81% T. fasciculata and 19% T. balbisiana. At the start of the study, no T. utriculata bromeliads were apparent in the cypress dome. Wildlife Biologist Marian Bailey informed me that T. utriculata used to be present in the Refuge, but she only knew of one remaining specimen, located near the Administrative Building; it was infested with M. callizona and soon died as a result of the infestation.

HHSP was monitored for 33 months. Total land area monitored was 0.45 hectares in hardwood forest; two Areas were mapped, one in an orange grove and one in hardwood forest. Twenty-one bromeliads were selected for monitoring, of which 33% were T. fasciculata, 13% were Tillandsia simulata Small, and 54% were T. utriculata. Tillandsia simulata is precinctive to Florida (Larson 2000c). Only two T. simulata plants were spotted in the monitoring area, making this a small sample. Tillandsia variabilis Schlechtendal was present in HHSP but not in the Sections that were monitored.

FSSP was monitored for 24 months. Total land area monitored was 0.04 hectares and included four Areas, three in swamp forest, and one on the side of a service road running through swamp forest. Seventy-seven bromeliads were selected for monitoring; the population was composed of 32% T. fasciculata, 10% T. utriculata, 12% T. balbisiana, 29% T. pruinosa Swartz, 3% T. variabilis, and 14% Guzmania monostachia L. The three Areas in the swamp were small patches each with a dominant species (T. utriculata, T. pruinosa, and G. monostachia); the Area on the service road was a combination of the species listed for FSSP. The percent composition of the species given here is likely not representative of the surrounding land because FSSP has more species than those included in this study (T. flexuosa Swartz, T. paucifolia Baker, Catopsis berterioniana Schultes, C. floribunda Brongniart, and C. nutans Swartz; Larson 2000c), and because the bromeliads tend to grow in patches such as the three out of four Areas mapped in FSSP.

SSSP covered 0.57 hectares; three Areas were mapped, one each in a cypress dome, a swamp forest, and an oak hammock. One hundred eighteen bromeliads were selected for monitoring and included 78% T. fasciculata, 10% T. balbisiana, 11% T. paucifolia, and 1% T. simulata. Tillandsia paucifolia were located on the edge of the cypress dome and co-existed with small and medium sized T. fasciculata and T. balbisiana.