Habitats In Florida Research Articles

Development of an assay for the detection of the federally threatened Florida eastern indigo snake (Drymarchon couperi) using soil eDNA

AbstractAccurate information on species range contraction is the cornerstone of effective biodiversity conservation. The eastern indigo snake (Drymarchon couperi) is an apex predator in Florida and, similar to many species native to Florida, is threatened by widespread habitat destruction. Environmental deoxyribonucleic acid (eDNA) monitoring of this elusive snake would provide a non‐invasive approach to improve our knowledge of the species' range and distribution. We designed and tested an eDNA assay that can detect the presence of D. couperi from soil samples from their natural scrub habitat in Florida. We validated our assay in silico, in vitro, and in situ. Furthermore, we investigated the influence of temperature and humidity on the degradation rate of eDNA over time. We successfully amplified the cytochrome b gene for D. couperi at concentrations as low as 3 × 10−3 ng/μL and successfully detected the presence of D. couperi in 2 of 30 in situ field soil samples. The degradation experiment resulted in detectable DNA for 10 days. Interestingly, temperature and humidity had no effect on the degradation rate of eDNA in our experimental conditions. This study provides support for soil eDNA applications to detect the presence of a federally threatened species in their natural environment bolstering our ability to monitor the conservation and management of imperiled species. Environmental DNA provides an additional conservation tool to quickly and effectively monitor species range shifts driven by multiple anthropogenic stressors to promote the persistence of imperiled species.

Description of juvenile instars of Scapheremaeus tonatiuh Palacios-Vargas, Ríos & Vázquez, 1998 (Acari, Oribatida, Cymbaeremaeidae)

The oribatid mite species Scapheremaeus tonatiuh (Oribatida, Cymbaeremaeidae) is recorded for the first time in the U.S.A. (initially described from Mexico). Its juvenile instars are described, based on materials collected from arboreal habitats in Florida, U.S.A. (Neotropical region). The larval instar is characterized by the presence of gastronotic setae с3, la, lm, lp long, lanceolate having setiform apex, and h1 very long, subflagellate; the nymphal instars are characterized by the presence of exuvial scalps, 12 pairs of gastronotic setae (da, dm, dp absent) of which setae с3, la, lm, lp, h1, h2 are long, phylliform but h3 is very long, subflagellate. The main morphological traits of the adult are summarized.

Dioecy hotspots in Southeast Florida (U.S.A.), especially Saw Palmetto (Serenoa repens, Arecaceae) thickets

A survey of woody marshland hummocks, of Saw Palmetto (Serenoa repens, Arecaceae) thickets, and of additional Southeast Florida habitats revealed multiple sites with dioecy rates of 50–100%, especially in the Saw Palmetto thickets. These rates exceeded any encountered for woody species in a literature review globally or for Florida. A particularly notable feature of the thicket sites is extreme thick low-elevation palm frond canopy coverage, consistent with the historical perspective that a benefit of dioecy is sexual selection for seed quality where harsh ecological filters limit establishment.

Effects of invasive plant haplotypes on a biological control agent (Lepidelphax pistiae) fecundity and impact

ABSTRACT Pistia stratiotes L. is an invasive floating plant that alters native habitats in Florida by forming thick mats that shade out submerged vegetation and obstruct navigation. Multiple genotypes of this plant have been identified from locations across its native and adventive ranges including types from throughout the Americas, the Caribbean, Asia, and Australia. We investigated the performance of a known monophagous insect, Lepidelphax pistiae, on nine P. stratiotes haplotypes (from four clades) in no-choice experiments and found that while L. pistiae performance varied on different haplotypes, there was considerable overlap in fitness and impact among haplotypes. Lepidelphax pistiae did not distinguish between purported ‘native’ and ‘non-native’ haplotypes and did not perform better or cause more damage to South American haplotypes specifically, which would have supported its utility as a biocontrol agent on the exotic haplotypes found in Florida. While L. pistiae is monophagous on P. stratiotes, it was not specific enough to differentiate consistently among the tested haplotypes and thus, may not be suitable as a biological control agent because of the potential threat they pose to native haplotypes of P. stratiotes in Florida.

Restored oyster reefs and living shorelines can augment predator trophic dynamics

Coastal habitat loss has led to declines in many higher trophic level predators. These declines can be mitigated through habitat restoration, which putatively enhances predator populations and trophic dynamics by creating foraging opportunities in reestablished habitat, but this lacks empirical support. Here, we assess the prediction restored coastal habitat supports sportfish feeding relationships similar to natural habitat, at restored oyster reefs (Crassostrea virginica) and living shoreline habitats in Florida, U.S.A. Stable isotopes and gut contents were analyzed from young sportfish (i.e. predatory fish targeted by anglers) collected at control and restored sites for up to 3 years. The influence of habitat features, predator size, and prey availability on carbon and nitrogen isotope values were examined using a model species (mangrove/gray snapper [Lutjanus griseus]). In summary, sportfish species had distinct isotopic values, consuming similar prey but in different proportions between habitats. Prey abundance and richness, and reef height were influential predictors of L. griseus stable isotope values, with restored reefs contributing to their diet more than controls according to Bayesian mixing models. The trophic niche area of L. griseus and their predominant prey achieved trophic equivalence between restored and natural oyster reefs within 1 year following restoration. Stabilized living shorelines attained trophic equivalency to natural shorelines, but may take longer to accrue prey for some species. These findings generate fundamental ecological knowledge and actionable science, including targets, timelines, and indicator species, that natural resource managers and restoration practitioners can use to assess trophic structure and success of coastal habitat restoration.

Trypanosoma cruzi infection in mammals in Florida: New insight into the transmission of T. cruzi in the southeastern United States.

In Latin America, synanthropic mammalian reservoirs maintain Trypanosoma cruzi, a parasitic protozoan, where they facilitate the transmission of the parasite to humans and other reservoir hosts in peridomestic settings. In the United States, raccoons (Procyon lotor) and Virginia opossums (Didelphis virginiana) are known synanthropic T. cruzi reservoir hosts; however, the role these species have in the peridomestic transmission cycle in the US is not well understood. This study aimed to identify the suite of mammalian reservoirs of T. cruzi in Florida. We also compared infection prevalence in raccoon populations sampled from within and outside of the estimated distribution of the common T. cruzi vector in Florida to gain insight into how the arthropod vector distribution impacts the distribution of infected reservoirs in the state. Finally, to investigate the impact of peridomestic landscapes on parasite prevalence, we compared the prevalence of T. cruzi-infected raccoons and opossums across five paired peridomestic and sylvatic sites. We live-trapped and collected peripheral blood samples from 135 raccoons, 112 opossums, 18 nine-banded armadillos (Dasypus novemcinctus), and nine species of rodents in north central Florida. Using quantitative PCR methods, we found that raccoons (42.2%, 95% CI [34.2-50.7%]) and opossums (50.9%, 95% CI [41.8-60.0%]) were infected with T. cruzi and the prevalence across habitats was similar for both raccoons (peridomestic: n=77, 44.2%, 95% CI [33.6-55.3%], sylvatic: n=58, 39.7%, 95% CI [28.1-52.5%]) and opossums (peridomestic: n=66, 48.5%, 95% CI [36.8-60.3%], sylvatic: n=46, 54.3%, 95% CI [40.2-67.8%]). Raccoons sampled outside the estimated distribution of Triatoma sanguisuga were not infected with T. cruzi (n=73, 0.0%, 95% CI [0.0-5.0%]). Our study did not indicate that peridomestic habitats in Florida maintained a higher infection prevalence than their sylvatic counterparts; however, we did find a difference in prevalence within vs. outside the estimated vector distribution in Florida.

Salinity and temperature affect the symbiont profile and host condition of Florida USA blue crabs Callinectes sapidus

Subtropical Florida blue crabs, Callinectes sapidus, exhibit differing life history traits compared to their temperate counterparts, likely influencing symbiont infection dynamics. Little information exists for Florida C. sapidus symbiont profiles, their distribution among various habitats, and influence on crab condition. Using histopathology, genomics, and transmission electron microscopy, we describe the first symbiont profiles for Florida C. sapidus occupying freshwater to marine habitats. Twelve symbiont groups were identified from 409 crabs including ciliophorans, digenean, microsporidian, Haplosporidia, Hematodinium sp., Nematoda, filamentous bacteria, gregarine, Callinectes sapidus nudivirus, Octolasmis sp., Cambarincola sp., and putative microcell. Overall, 78% of C. sapidus were documented with one or more symbiont groups demonstrating high infection rates in wild populations. Environmental variables water temperature and salinity explained 48% of the variation in symbiont groups among Florida habitats, and salinity was positively correlated with C. sapidus symbiont diversity. This suggests freshwater C. sapidus possess fewer symbionts and represent healthier individuals compared to saltwater populations. Crab condition was examined using the reflex action mortality predictor (RAMP) to determine if reflex impairment could be linked to symbiont prevalence. Symbionts were found positively correlated with crab condition, and impaired crabs were more likely to host symbionts, demonstrating symbiont inclusion may boost predictive ability of the RAMP application. The microsporidian symbiont group had a particularly strong effect on C. sapidus reflex response, and impairment was on average 1.57 times higher compared to all other symbiont groups. Our findings demonstrate the importance of considering full symbiont profiles and their associations with a spatially and temporally variable environment to fully assess C. sapidus population health.

Temporal variability of microbial response to crude oil exposure in the northern Gulf of Mexico

Oil spills are common occurrences in the United States and can result in extensive ecological damage. The 2010 Deepwater Horizon oil spill in the Gulf of Mexico was the largest accidental spill recorded. Many studies were performed in deep water habitats to understand the microbial response to the released crude oil. However, much less is known about how planktonic coastal communities respond to oil spills and whether that response might vary over the course of the year. Understanding this temporal variability would lend additional insight into how coastal Florida habitats may have responded to the Deepwater Horizon oil spill. To assess this, the temporal response of planktonic coastal microbial communities to acute crude oil exposure was examined from September 2015 to September 2016 using seawater samples collected from Pensacola Beach, Florida, at 2-week intervals. A standard oil exposure protocol was performed using water accommodated fractions made from MC252 surrogate oil under photo-oxidizing conditions. Dose response curves for bacterial production and primary production were constructed from 3H-leucine incorporation and 14C-bicarbonate fixation, respectively. To assess drivers of temporal patterns in inhibition, a suite of biological and environmental parameters was measured including bacterial counts, chlorophyll a, temperature, salinity, and nutrients. Additionally, 16S rRNA sequencing was performed on unamended seawater to determine if temporal variation in the in situ bacterial community contributed to differences in inhibition. We observed that there is temporal variation in the inhibition of primary and bacterial production due to acute crude oil exposure. We also identified significant relationships of inhibition with environmental and biological parameters that quantitatively demonstrated that exposure to water-soluble crude oil constituents was most detrimental to planktonic microbial communities when temperature was high, when there were low inputs of total Kjeldahl nitrogen, and when there was low bacterial diversity or low phytoplankton biomass.

"Nicoletia" tergata Mills, 1940 rediscovered in Florida and confirmed as the first species of the Coletiniinae (Zygentoma: Nicoletiidae) in North America.

"Nicoletia" tergata Mills, 1940 is redescribed from new material recently collected in subterranean habitat in Florida as well as examination of some of the type specimens. The species is placed in a new genus Gibboletia within the subfamily Coletiniinae and thus represents the only species of this subfamily so far known in North America. Molecular data (16S rRNA) from one of two populations suggest they may represent different species; however, morphological differences were not found within or between populations. The legs of all specimens from one population reacted with the mounting medium whereas the other population mostly did not, suggesting a physiological difference may exist.

Home Range and Habitat Use of Florida Box Turtles (Terrapene bauri) in the Ten Thousand Islands, Florida

For taxa with dispersal limitations, such as freshwater turtles, an understanding of their habitat and spatial needs can elucidate their risk to expected environmental and climatic changes. Florida Box Turtles (Terrapene bauri), a species of greatest conservation need, occurs in a diverse range of subtropical habitats on the Florida peninsula, including low-lying coastal areas subject to threats from climate change and sea level rise. We used radiotelemetry to assess the home range size and habitat use of Florida Box Turtles on a 37-ha anthropogenic, shell work island in southwestern Florida at the margin of its climatic niche. Home range calculated as 100% minimum convex polygons ranged from 0.29–1.52 ha with an average of 0.81 ha, which is consistent with, but smaller than, other parts of their range, and annual survivorship was estimated to be 0.875 (95% confidence interval = 0.67–1). Florida Box Turtles were most commonly located in tropical hardwood hammock forests (50.9%); other habitat use included shrub-scrub-cactus (29.6%), mangrove forest (13.4%) and shell barren (6.0%). Additional information on reproductive output, growth, temporal variation in survival, and response to disturbance such as hurricanes, storm overwash, and sea level rise is necessary to assess the long-term persistence of this population in the face of anticipated transitions of Florida's habitats because of global climate change.

Modeling the impact of invasive species litter on conditions affecting its spread and potential regime shift

Many introduced plants pose invasion risks globally and threaten the biodiversity of native ecosystems. Such non-native plants can become invasive when they have advantages over native plants, such as having fewer natural enemies. Invasive plants often have the ability to alter ecosystem properties after they have become established, which can make it difficult to eliminate the invasive. In principle, this can cause a regime shift that may not be reversed through intense control efforts that increase mortality and reduce growth of the invasive species. Here we use spatially explicit agent-based modeling to simulate the invasion of an introduced tree species into a habitat occupied by a native species. The model describes an invasive tree with fast growth and high seed production and, in addition, produces litter that has a suppressive effect on native seedlings. These are properties, for example, shared by the invasive Melaleuca quinquenervia in southern Florida habitats. We use simulation modeling to test the following logical hypotheses: Partial suppression of native tree seedlings by the invasive tree's litter (1) will accelerate the spread of the invasive tree into native vegetation, (2) will impede efforts to control invasive spread through biocontrol, and (3) can cause a regime shift that is not reversed even if the biocontrol lowers invasive growth and reproduction to levels substantially lower than those of the native species. Additionally, (4) the earlier in the invasion biocontrol is introduced, the more effective it will be in reversing the invasion. The simulations support all four hypotheses. While these results highlight the potential for biocontrol of invasive tree species, our findings also suggest that successful elimination of positive litter feedbacks and invasive spread may critically depend on the timing of control efforts within the invasion process.

A reflex action mortality predictor (RAMP) for commercially fished blue crab Callinectes sapidus in Florida

The paucity of data on discard mortality in the commercial blue crab fishery contributes significant uncertainty to stock assessments. The reflex action mortality predictor (RAMP) method is used to predict mortality of commercially fished species by establishing a relationship between reflex impairment and the likelihood of mortality (RAMP curve). The present study adapted the RAMP method to commercially fished blue crabs in two unique habitats in Florida, the Tampa Bay estuary and the St. Johns River. The euryhaline nature of blue crabs permits the fishery to operate in myriad habitats, which adds complexity to cumulative effects that influence discard mortality. A total of 697 crabs were assessed, and a RAMP curve was generated. Logistic regression analyses determined that reflex impairment score, injury score, and salinity are strong predictors of discard mortality, with 91% of predictions correct. For every 1-unit increase in reflex impairment and injury score, mortality was 2.71 and 1.65 times more likely, respectively. Additionally, for every 1-SD (11.35 ppt) increase in salinity, mortality was 2.17 times more likely. Crab size, sex, water temperature, and emersion time minimally influenced mortality. The present study is the first crustacean RAMP research that included water quality and demonstrated that its inclusion increases the predictability of discard mortality. The RAMP curve can be used as a tool to estimate discard mortality aboard commercial vessels and discard mortality in future stock assessments.

Microplastics in Florida, United States: A Case Study of Quantification and Characterization With Intertidal Snails

Concentrations of microplastics are increasing within the oceans, including waters surrounding Florida, United States. Miles of sandy beaches make the sunshine state a prime tourist destination leading to an increased amount of pollution along Florida coasts. Microplastics can cause damage to intertidal organisms, as well as causing issues up the food chain with biomagnification and seafood consumers, such as humans. Florida is also subject to hurricanes which often distribute sediments, filling the water column with previously settled microplastics. These factors make Florida a special case to review considering the state is affected heavily by hurricanes and tourism, which can contribute to microplastic concentrations in the Gulf of Mexico. The focus of this study was to quantify, characterize, and compare microplastics contamination in two predatory marine snail species from intertidal habitats in Florida, United States Ingestion results were also compared to microplastics contamination of water samples collected from the same locations. Red-mouth rock shell (Stramonita haemastoma, n = 30) and Crown conch (Melongena corona, n = 30) snails were collected from intertidal habitats in Florida and digested for microplastics quantification. Water samples were filtered and microplastics were quantified. 256 microplastics, of which 93% were microfibers and 7% were microfragments were isolated from snails (n = 60). Additionally, 67 microplastics were isolated from 8 L of seawater (8.375 microplastics/L), of which 97% were microfibers and 3% were microfragments. This is the first known study to demonstrate microplastics contamination of tissues in predatory marine intertidal snails. Marine intertidal snails may be good organisms for biomonitoring of microplastics in intertidal sandy habitats.

Dumpsters and other anthropogenic structures as habitat for invasive African rock agama lizards in Florida

Invasive species often use habitat differently than native species and can benefit by occupying underutilized habitats during the invasion process. The Peter’s Rock Agama (Agama picticauda)—native to savannahs of sub-Saharan Africa—is successfully invading urban habitats in Florida, USA. During a field trip in urban southern Florida, we observed apparently high A. picticauda abundance around dumpsters used for human refuse, potentially because dumpsters provide refuge, thermoregulatory opportunities, abundant arthropod prey, and harbor few competitors. In this study, we surveyed abundance and built resource selection functions to better understand habitat use of A. picticauda in urban southern Florida. We tested whether hypothesized habitat features predictably influenced the abundance and occupancy of A. picticauda among sites and whether individuals used specific habitat features within sites. Across sites, we found A. picticauda abundance was positively correlated with the number of dumpsters, and, within sites, dumpsters were preferentially selected as habitat. Similarly, we also found two other anthropogenic structures, building crevices and electrical units, were positively selected habitats at population and individual scales. We hypothesize that dumpsters, crevices, and electrical units are selected resources because they are underutilized habitats by other species and they provide refuge, beneficial thermoregulatory opportunities, and in the case of dumpsters, foraging opportunities. Our study provides the first quantitative assessment of urban habitat use by non-native A. picticauda, and supports the importance of human structures as habitat. Our results suggest the intriguing possibility that the A. picticauda invasion in Florida may be exploiting a vacant niche in urban habitats during the invasion process.

Bottom-up factors determine local, but not regional, distribution of a biological control agent against invasive Lygodium microphyllum

The efficacy of biological control as a tool to manage invasive plants relies on widespread agent establishment, yet achieving such establishment remains a central challenge to the field. One potential explanation for patchy distributions of agents is the role of ‘bottom-up’ factors that influence plant quality and, in turn, local agent establishment. We investigated the roles of two bottom-up factors, soil fertilization and inundation, on establishment of the leaf galling mite Floracarus perrepae (Acariformes; Eriophyidae), an agent introduced to control the noxious vine Lygodium microphyllum (Lygodiaceae; Old World climbing fern) found in both upland and inundated habitats in Florida, USA. We conducted a series of shade house experiments to quantify bottom-up factors under controlled settings, and then validated these finding using a regional survey of 19 L. microphyllum infestations. Our shade house experiments demonstrated positive effects of fertilizer and negative effects of soil inundation on F. perrepae populations. Our regional survey showed no difference in leaf percent N between sites with or without F. perrepae galls. However, when we restricted our analysis to the area of the state where the mite had established, sites with galls had 33% higher leaf N than sites without galls, and nearly all inundated sites lacked galls. Bottom-up factors determine local mite establishment, but regionally, other factors (e.g., genetic factors underlying plant susceptibility) are likely at play. Our study demonstrates both the consequences and limitations of bottom-up factors to shape distributions of biological control agents in the field and has important implications for effective management of invasive plants.

Two new species of Unikaryon (Microsporidia) hyperparasitic in microphallid metacercariae (Digenea) from Florida intertidal crabs

The genus Unikaryon (Microsporidia) holds exclusively hyperparasites of Platyhelminthes. Four species of Unikaryon are presently known from trematodes infecting mollusks and fish, and one from a cestode infecting a fish. Here we report two species of Unikaryon from microphallid trematode metacercariae parasitizing the brachyuran crabs, Panopeus herbstii and Pachygrapsus transversus, collected from intertidal habitats in Florida. The first microsporidium, which we assign here to a new species, Unikaryon panopei sp. n., was isolated from Microphallus sp. encysted in Panopeus herbstii from Tampa Bay. The specific designation for the second Unikaryon sp. (Unikaryon sp. 2), which occurred in metacercaria of Diacetabulum sp. found in P. transversus from the Florida Keys, is pending due to the lack of SSrDNA sequence data. Light and electron microscopy demonstrates that both species display characteristics of the genus Unikaryon including the arrangement of spores in sets of two, large posterior vacuole, and eccentric position of the polar filament. Spores of Unikaryon panopei sp. n., unlike those of Unikaryon sp. 2, assemble in large membrane-bound masses containing hundreds of organisms, and display a larger number of polar filament coils – 7–8, compared to 4–5 in Unikaryon sp. 2 The SSUrDNA-inferred phylogenetic analysis places Unikaryon panopei in one clade with Unikaryon legeri, the only other molecularly characterized member of the genus, with 94% of SSUrDNA similarity. These findings increase the number of species parasitizing trematodes and broaden the host range of Unikaryon spp.

Location and extent of unoccupied panther (Puma concolor coryi) habitat in Florida: Opportunities for recovery

Breeding Florida panthers (Puma concolor coryi) are currently restricted to a small area in southwest Florida south of the Caloosahatchee River. Expansion of their range and numbers is necessary for long-term survival and recovery. We estimated the amount and location of breeding panther habitat still remaining in Florida using a modified version of a published random forest habitat model. Unexpectedly, we found that a large proportion of the state (41%) is still suitable panther habitat. Most of this habitat is concentrated in the Panhandle, Big Bend region, and northern third of the peninsula, although there are also smaller islands of habitat in central Florida, in addition to the occupied range in south Florida. Five large areas with suitable habitat for potential reestablishment of breeding panther populations were identified: Eglin Air Force Base, Apalachicola National Forest and vicinity, Big Bend region and the northwest peninsula, Osceola National Forest and vicinity, and Ocala National Forest. Combined, these areas could theoretically support approximately 499–798 adult and subadult panthers, contributing to or achieving recovery goals. These areas were analyzed with regard to habitat quality and extent, highway density, human residential density, potential for livestock depredations, and amount of protected public lands, and compared with the currently occupied panther range in south Florida. In some cases, the unoccupied areas matched or exceeded the currently occupied panther range with regard to these indicators. We conclude that there is ample suitable habitat remaining in the state of Florida for recovery of the Florida panther. However, due to existing impediments to dispersal and anticipated rapid development in Florida, natural recolonization of unoccupied habitat in north Florida seems unlikely.

Shell Lesions Associated With Emydomyces testavorans Infection in Freshwater Aquatic Turtles.

A newly described onygenalean fungus, Emydomyces testavorans, has been isolated from ulcerative shell and skin lesions of freshwater aquatic chelonians. To investigate the shell lesions associated with infection and determine if any lesional features were unique to E. testavorans, tissues from turtles housed in zoological institutions (n = 45) in the United States and free-living turtles (n = 5) submitted for diagnostic biopsy or necropsy were examined. Free-living turtles were from geographically distinct habitats in Florida (n = 1) and Washington (n = 4) at the time of sampling. Histologic shell sections were evaluated for the presence or absence of specific lesional features. Infection with E. testavorans was evaluated in all cases by screening GMS (Grocott-Gomori's methenamine silver)-stained histologic sections for the presence of morphologically consistent fungi and by quantitative PCR (polymerase chain reaction) on representative frozen tissue or formalin-fixed paraffin-embedded sections. Additionally, culture was performed for 15 cases with available fresh/frozen tissue. In total, there were 17 PCR-confirmed E. testavorans cases, 29 cases with morphologically consistent fungi on GMS-stained sections, and 21 cases of shell lesions without histologic or molecular evidence of E. testavorans infection. Epithelial inclusion cysts, defined as cystic structures within the dermis lined by keratinized stratified squamous epithelium and containing necrotic bone and keratin debris, were significantly (P < .01) associated with E. testavorans infection. Other significantly associated shell lesions included squamous metaplasia, hyperkeratosis, inflammation, and osteonecrosis (P < .05). This study identified characteristic shell lesions associated with E. testavorans infection. Further studies to prove causality are needed.

The impact of Hurricane Michael on longleaf pine habitats in Florida

Global biodiversity hotspots (GBHs) are increasingly vulnerable to human stressors such as anthropogenic climate change, which will alter the ecology of these habitats, even where protected. The longleaf pine (Pinus palustris) ecosystem (LPE) of the North American Coastal Plain is a GBH where disturbances are integral for ecosystem maintenance. However, stronger storms due to climate change may be outside their historical norm. In this study, we estimate the extent of Florida LPE that was directly affected by Hurricane Michael in 2018, an unprecedented Category 5 storm. We then leveraged a unique data set in a Before-After study of four sites within this region. We used variable-area transects and generalized linear mixed-effects models to estimate tree densities and logistic regression to estimate mortality by size class. We found at least 28% of the global total remaining extent of LPE was affected in Florida alone. Mortality was highest in medium sized trees (30–45 cm dbh) and ranged from 4.6–15.4% at sites further from the storm center, but increased to 87.8% near the storm center. As the frequency and intensity of extreme events increases, management plans to mitigate climate change need to account for large-scale stochastic mortality events to preserve critical habitats.

Soil biotic and abiotic conditions negate invasive species performance in native habitat

BackgroundMost studies on plant invasion consider the enemy release hypothesis when analyzing native habitats. However, the lower performance of invasive species in the native habitats can be the result of unfavorable soil conditions in the native habitats. While soil biotic and abiotic factors have a potential to restrict the growth of invasive species in their native habitats, our understanding of belowground environment of invasive species in their native habitats is very limited. In this study, we analyzed soil characteristics associated with an exotic invasive plant, Old World Climbing Fern (Lygodium microphyllum), in its native habitat in Australia and the recipient habitat in South Florida. Rhizosphere soil samples from both habitats were analyzed for soil physical, chemical and biological characteristics.ResultsSoil characteristics in the recipient habitats were significantly different compared to those in the native habitats. Soil samples from the native habitat had low soil pH, and high concentrations of elements such as aluminum and zinc which are phytotoxic in acidic soil environments. Additionally, mycorrhizal fungi spores were more diverse in the recipient habitat in Florida compared to the native habitat in Australia.ConclusionOverall, our results indicate that growth of an invasive plant in its native habitats could be restricted by the toxic effects associated with strong soil acidity. Results from this study indicate that invasive plants not only escape from their natural herbivores but also from toxic soil environment in their native habitats.