Eumops Floridanus Research Articles

Wetland restoration enhances habitat for an endangered bat, Eumops floridanus

Restoring lost or degraded wetlands is a major challenge in contemporary conservation. Understanding how wetland restoration and changes in hydrology affect wildlife is increasingly urgent for endangered species conservation. This is especially pertinent for the endangered Florida bonneted bat (Eumops floridanus), whose range is almost entirely contained within one of the world's most iconic wetland systems, the Greater Everglades Ecosystem. We investigated how E. floridanus may respond to future hydrological and vegetation changes associated with current and planned Everglades hydrologic restoration efforts. We conducted acoustic surveys at 194 random points stratified across a restoration gradient (no hydrologic restoration, partial hydrologic restoration, full hydrologic restoration, and reference). Using generalized linear mixed models, we determined the most important predictors explaining variation in bat activity and foraging likelihood. Positive associations between bat activity and several hydrologic variables expected to increase with restoration (hydroperiod, water depth, distance to canals, and extent of freshwater forested wetlands, ecologically intact reference areas, and zones with full hydrological restoration) suggest that foraging habitat for this species will likely benefit from hydrologic restoration both in the near term (immediate increases in hydroperiod and water depth) and in the longer term (as freshwater forested wetlands expand). Our results inform immediate management decisions for this species and suggest the benefits of restoration for wildlife adapted to historically longer hydroperiods and greater water depths, which are anticipated to increase with the gradual return of natural hydrological regimes.

Patterns of Florida Bonneted Bat Occupancy at the Northern Extent of Its Range

Abstract The Florida bonneted bat Eumops floridanus is a rare, endemic bat of South Florida that roosts in woodpecker cavities and anthropogenic structures such as roofing tiles, chimneys, and bat houses. The northernmost occurrences of the bonneted bat are from mature pine forests at the Avon Park Air Force Range, Florida. We used ultrasonic acoustic recorders to understand bonneted bat activity and habitat occupancy. We modeled occupancy using a hierarchical Bayesian analysis and included site- and time-specific covariates of detection probability and site-specific covariates of occupancy. Probability of detection was low throughout Avon Park Air Force Range but increased with Julian date. In most habitats, occupancy was poorly estimated, except for flatwood mature pinelands where occupancy was low (0.23 ± 0.06). As distance from red-cockaded woodpecker colonies increased, occupancy decreased (β = −1.19 ± 0.26 SD). At the northernmost extent of the range, and throughout much of the historic range, increasing the expanse of mature, fire-maintained forest systems will increase habitat for the bonneted bat and lead to faster population recovery.

Strong population genetic structure and cryptic diversity in the Florida bonneted bat (Eumops floridanus)

Knowledge of the genetic structure and cryptic diversity is essential for the conservation of endangered species. We conducted a genetic survey of the federally endangered Florida bonneted bat (Eumops floridanus) sampled from its USA range in southern Florida. Florida bonneted bats are primarily found in four regions separated by approximately 100 to 250 km, including three western natural areas: Babcock Webb WMA (BW), Polk County (PC), and Collier County (CC) and one urban population on the east coast, Miami-Dade County (MD). We used 22 microsatellite loci and cytochrome b sequences to assess the extent of connectivity and levels of genetic diversity. Populations were highly differentiated at microsatellite loci (overall FST = 0.178) and model-based and ordination analyses showed that MD was the most distinct among pairwise comparisons. Regional populations were small (Ne < 100) with no evidence of inbreeding. Contemporary migration and historic gene flow suggested that regional populations have not frequently exchanged migrants, and thus the divergence among western regions was likely a result of genetic drift. Significantly, mitochondrial DNA revealed that haplotypes from MD were similar or shared with those recognized as Eumops ferox from Cuba and Jamaica, and divergent (1.5%) from the remainder of bonneted bats in Florida. Our data support the management of each of the four populations as distinct population segments, and that BW, PC and CC combined are on an independent evolutionary trajectory from bats in MD. Bonneted bats in Florida appear to harbor cryptic diversity that will require a reassessment of their taxonomy.

Eumops floridanus (Chiroptera: Molossidae)

Abstract Eumops floridanus (Allen, 1932) is a molossid commonly called the Florida bonneted bat or the Florida mastiff bat. Eumops floridanus is the largest species of bat in Florida and is one of 16 species in the genus Eumops. With one of the smallest distributions of any bat in the United States, it is endemic to southern peninsular Florida where it roosts in cavities of live and dead trees and man-made structures. Eumops floridanus was formerly classified as a subspecies of E. glaucinus but has been elevated to species level based on morphology. Due primarily to its restricted distribution, small population size, and the continued loss of habitat, E. floridanus is federally listed as “Endangered” (EN) by the United States Fish and Wildlife Service.

Evidence of resource-defense polygyny in an endangered subtropical bat, Eumops floridanus

Understanding sociality and animal behavior is critical for developing effective conservation strategies. Many tropical bat species form harems, where dominant males play key social roles by defending groups of females directly (female-defense polygyny) and/or the resources that females need (resource-defense polygyny). The Florida bonneted bat (Eumops floridanus) is an endangered subtropical species suspected to form harems, but our understanding of its social structure, reproduction, and behavior is rudimentary. In this study, we evaluated demographic variation in morphological and behavioral characteristics of Florida bonneted bats to test the hypothesis that this species forms harem groups and exhibits resource-defense polygyny at roost sites. We used a 4-year dataset of 341 individuals uniquely marked with passive integrated transponders (PIT tags), coupled with tri-annual capture records, to track activity patterns of bats at five roosts fitted with PIT tag readers. We identified the likely dominant males and other demographic groups in each roost using morphometric characteristics and reproductive status. We assessed differences between sexes and among status categories in three primary metrics: amount of activity at the roost, time of emergence, and initial foray duration per night. Dominant males consistently were the most active individuals at roosts and spent the least amount of time away from roosts during forays, relative to females and other males. Females spent more time away from roosts than males and shared similar foraging activity patterns regardless of status. Our findings suggest that Florida bonneted bats form small harem groups that are active year round. Male bats exhibit characteristics of resource-defense polygyny at roost sites and a size-biased hierarchy, with the largest reproductively active males appearing to defend the roost at the expense of time spent foraging. We suggest that the roost site represents a critical, limited and defendable resource for male Florida bonneted bats to gain access to females, which has important implications for the conservation and enhancement of roost sites. Our study highlights the importance of accounting for differences in behavior across demographic groups and social roles when considering resource needs for imperiled species.

High Incidence of Hypopigmented Marks in the Endangered Florida Bonneted Bat

Abstract Aberrant patches of white skin or fur known as hypopigmented marks have been observed in many mammal species worldwide, but they are typically limited to only a few individuals in a population. Hypopigmented marks were documented in only two museum specimens of the federally endangered Florida bonneted bat (Eumops floridanus) as early as 1950, but recent observations suggest that these marks may be more common in this species than previously believed. To better understand the occurrence and persistence of hypopigmented marks in Florida bonneted bats, we evaluated the variation in frequency, compared effects on survival, and assessed spatial and temporal differences of specimens at an intensively studied site and across the species range. From 2014 through 2017, we regularly captured Florida bonneted bats for demographic studies at Babcock–Webb Wildlife Management Area in Charlotte County and we observed hypopigmented marks on 172 (80.8%) of 213 individuals, the highest incidence known for bats. The proportion of hypopigmented marks did not differ with sex, age at first capture, or reproductive status, and importantly, we documented the persistence of hypopigmented marks in individuals over multiple months. We also found no difference in survival or capture probability between hypopigmented and solid-colored individuals. Using data from concurrent mist-net studies, we assessed the proportion of Florida bonneted bats with hypopigmented marks across the species range and found a higher proportion of individuals with hypopigmented marks in the two northern counties (80.8% in Charlotte County and 61.5% in Polk County) compared with the two southern counties (21.1% in Miami–Dade County and 16.7% in Collier County). Additionally, we compared the proportion of hypopigmented individuals in Miami–Dade County between recently captured/collected bats (post-2004) and historically (pre-1965) collected museum specimens and found more hypopigmented marks in recently captured bats. The persistence of hypopigmented marks over time, the presence of marks on bats from different locations, and our finding of no effect of age on the presence of marks all strongly suggest that the hypopigmented marks in Florida bonneted bats are the result of genetic rather than environmental factors. Further study is required to understand the mechanism underlying the high incidence of hypopigmented marks and to determine whether the prevalence of hypopigmented marks indicates low genetic diversity that could threaten Florida bonneted bats.

Canopy Cover Shapes Bat Diversity across an Urban and Agricultural Landscape Mosaic

SummaryHuman alteration of the planet’s terrestrial landscapes for agriculture, habitation and commerce is reshaping wildlife communities. The threat of land cover change to wildlife is pronounced in regions with rapidly growing human populations. We investigated how species richness and species-specific occurrence of bats changed as a function of land cover and canopy (tree) cover across a rapidly changing region of Florida, USA. Contrary to our predictions, we found negligible effects of agriculture and urban development on the occurrence of all species. In contrast, we found that a remotely sensed metric of canopy cover on a broad scale (25 km2) was a good predictor of the occurrence of eight out of ten species. The occurrence of all smaller bats (vespertilionids) in our study increased with 0–50% increases in canopy cover, while larger bats showed different patterns. Occurrence of Brazilian free-tailed bats (Tadarida brasiliensis) decreased with increasing canopy cover, and Florida bonneted bats (Eumops floridanus) were not influenced by canopy cover. We conclude that remotely sensed measures of canopy cover can provide a more reliable predictor of bat species richness than land-cover types, and efforts to prevent the loss of bat diversity should consider maintaining canopy cover across mosaic landscapes with diverse land-cover types.

Restoring historical fire regimes increases activity of endangered bats

BackgroundFire suppression has altered ecological communities globally. Prescribed fire regimes strive to restore function to these fire-dependent ecosystems by mimicking natural fire regimes. Although fire frequency is a widely acknowledged component of fire regimes, the importance of fire seasonality for biodiversity is less clear but appears to play a critical role for a variety of taxa, particularly in the North American Coastal Plain. In subtropical Florida, USA, fire historically occurred primarily at the transition from the dry to wet season (early wet season: April to June) when dry fuel accumulation coincides with a high incidence of lightning. We investigated the effects of fire frequency and season on endangered Florida bonneted bats (Eumops floridanus [G.M. Allen, 1932]), a species endemic to a region that evolved with frequent fires.ResultsWe surveyed bat activity acoustically in 149 sites in fire-dependent vegetation communities (pine flatwoods and prairies), and evaluated the effects of fire frequency and seasonality, using burn records from the previous 18 years. Variation in bat activity was best explained by both fire frequency and season: bat activity decreased with early wet season (April to June) burn interval and increased with dry season (November to March) burn interval. Bat activity and foraging activity were highest in sites burned at > 3- to 5-year intervals during the early wet season.ConclusionFires during the historic fire season at a moderate frequency (> 3 to 5 yr) appear to optimize habitat for bats in both pine flatwoods and prairies, likely through increases in roosts, flight space, and insect prey availability. It appears that Florida bonneted bats are fire-adapted and benefit from prescribed burn programs that closely mimic historical fire regimes. We encourage consideration of both fire frequency and seasonality when managing ecosystems with fire.

In-flight social calls: a primer for biologists and managers studying echolocation

Recent technological advances have permitted collection of immense data sets through automated recordings that are primarily aimed at capturing bat echolocation. Analyses of echolocation calls are used to identify species, relative abundance, and some aspects of behaviour, such as foraging or commuting. Here we propose that social calls recorded in flight are also valuable tools for understanding bat ecology and behaviour. First, we examine how and why the acoustic structure of social calls differ from echolocation. Differences in form make social calls often, but not always, easy to identify. We then use a case study on in-flight song in Brazilian free-tailed bat (Tadarida brasiliensis (I. Geoffroy, 1824)) to show that what may appear as echolocation may instead be predominantly used for social communication. Next, we review three basic functions of in-flight social calls, including examples of each, and develop a framework for testing these alternative functions using automated recordings. In a second case study, we use automated recordings of the endangered Florida bonneted bat (Eumops floridanus (G.M. Allen, 1932)) to illustrate how behavioural information can be gleaned by examining patterns of social call production. Finally, we discuss why and how social calls provide novel information that can be crucial for conservation and management efforts.

Activity of an endangered bat increases immediately following prescribed fire

ABSTRACTSpatiotemporal responses of bats to fire are not well understood. Fire can indirectly influence bat activity through changes to understory vegetation, insect prey availability, and roost tree abundance. High‐flying bats may be less influenced by fire‐induced changes to the understory because they forage above the forest canopy. Fire‐dependent forests are prevalent across the range of the endemic Florida bonneted bat (Eumops floridanus), a large, high‐flying, and critically endangered species, yet effects of fire management on this species are completely unknown. To investigate short‐term responses of these bats to fire, we conducted pre‐post‐treatment‐control experiments in 4 prescribed burns during 2 seasons (dry, wet). For 12 nights pre‐burn and 24 nights post‐burn, we surveyed bat activity acoustically at 3 sites within each burn (treatment) and 3 adjacent sites (control). Using mixed‐effects models to test the effect of treatment on bat activity, we found that bat activity significantly increased post‐burn in treatment sites relative to control sites, with more pronounced effects during dry season burns. We also detected significantly more feeding buzzes (foraging activity) in treatment sites than control sites, and a negative trend over time in the burn effect size post‐burn. We suggest that bats are attracted to increased availability of insect prey immediately following burns, particularly during the dry season when prey may be limited. Our results suggest that burns have short‐term positive effects on Florida bonneted bats and that restoring fire to fire‐dependent forests may improve foraging habitat for this species. © 2018 The Wildlife Society.

Acoustic lure allows for capture of a high‐flying, endangered bat

ABSTRACTMist nets are commonly used to capture free‐flying bats; however, some bat species are very difficult to capture because of their flight behavior, habitat preferences, and ability to avoid nets. High‐flying, open‐space foragers are especially underrepresented by mist‐net surveys. Few studies have investigated the effectiveness of using acoustic lures (playbacks of conspecific vocalizations) to increase capture success of bats in mist nets. We tested the efficacy of an acoustic lure to capture a high‐flying rare molossid, the endangered Florida bonneted bat (Eumops floridanus), which had been captured only once away from a known roost prior to our research. We used a crossover experimental design with 2 lure treatments (nets with lures playing social call recordings from 2 different roosts) and 2 control nets (no lures) in 6 sites for 2 nights each. We captured 15 Florida bonneted bats in our treatment nets and 0 in our control nets. One lure had greater capture success (n = 13) than the other (n = 2), with a trend for greater captures of males (n = 11) than females (n = 4). We suggest that these differences were due to the social context in which the calls used in the lures were recorded. Our study demonstrated the utility of acoustic lures to capture Florida bonneted bats and expands research opportunities critical to the species’ conservation, such as the ability to use radio telemetry to track captured bats to unknown roosting and foraging areas. Our study also lays the foundation for future research into social call playbacks as a technique to lure other high‐flying and elusive bat species into mist nets. © 2017 The Wildlife Society.

Florida's Bats: Florida Bonneted Bat

The Florida bonneted bat is one of only two endangered species of bat in Florida and the state’s only endemic flying mammal (“endemic” means that it is found nowhere in the world but in Florida). With a 20-inch wingspan, it is Florida’s largest bat and the third largest of all 48 species of bats in the United States. The Florida bonneted bat was listed as federally endangered in 2013 because of concerns over habitat loss, degradation, and modification caused by humans. Additional concerns include the species’ small population size and restricted range, the small number of known colonies, their slow reproduction, and the relative isolation of separate populations of bonneted bats. This 3-page fact sheet explains how to differentiate Florida bonneted bats from velvety free-tailed bats and Brazilian free-tailed bats and explains what to do if you find one of these endangered bats. Written by Holly K. Ober, Terry Doonan, and Emily Evans, and published by the UF Department of Wildlife Ecology and Conservation, October 2016. WEC381/UW426: Florida's Bats: Florida Bonneted Bat (ufl.edu)

Social organization of an endangered subtropical species, Eumops floridanus, the Florida bonneted bat

Abstract Many Chiropteran species are gregarious, yet much remains to be learned about details of the sociality of most species. This is especially true for the endangered Eumops floridanus (Florida bonneted bat). Scant knowledge of the species’ natural history and ecological interactions has precluded the development of effective conservation strategies. We investigated several aspects of the social organization of E. floridanus roosting in bat houses in southwest Florida: group size, group composition, group stability, and seasonality of reproduction. Our findings suggest the species has characteristics more common to tropical bat species than temperate ones. The average roost size was 10 individuals, with colonies in a harem social structure all three times in the year they were assessed. Adults were much more likely than sub-adults to be recaptured at the same roosts during subsequent capture sessions. We suggest that the availability and distribution of roosts may alter the social structure of these bats and ultimately limit local populations. We did not find evidence of a distinct seasonal birthing period matching that of other temperate bat species. Results suggests the species is aseasonally polyestrous, making non-volant E. floridanus vulnerable to disturbance across a larger portion of the year than other bat species in the US.

Use of a Multi-Tactic Approach to Locate an Endangered Florida Bonneted Bat Roost

Abstract Effective strategies for bat conservation require knowledge of species-specific roost ecology. Thus, conservation planning is difficult for species with poorly understood roost use, such as the federally endangered Eumops floridanus (Florida Bonneted Bat). Prior to this study, only 1 active natural roost had been documented throughout the Florida Bonneted Bat's geographic range. Search efforts to locate new roosts using several techniques have been unsuccessful. Here we present a simple methodology that we successfully implemented to locate a second Florida Bonneted Bat natural roost. Using acoustics, cavity searches, and emergence observations, we documented a colony of Florida Bonneted Bats roosting in a Pinus elliottii (Slash Pine) snag in Florida Panther National Wildlife Refuge in Collier County, FL. Our discovery highlights the importance of snags, and provides additional details to state and federal agencies tasked with species recovery.

Speciation within Bonneted Bats (Genus Eumops): The Complexity of Morphological, Mitochondrial, and Nuclear Data Sets in Systematics

We phylogenetically analyze 705 base pairs of the cytochrome-b gene and 351 amplified fragment length polymorphism (AFLP) bands from populations of the karyotypically variable Wagner’s bonneted bat, Eumops glaucinus, and the Florida bonneted bat, Eumops floridanus (Chiroptera: Molossidae). Three karyotypes have been documented across the range of E. glaucinus, and we report that the karyotype from Cuba is morphologically similar to that from Jamaica. A 4th karyotype is present in specimens from western Ecuador. Three distinct lineages are present in both the cytochrome-b and AFLP trees. One lineage is restricted to western Ecuador and exhibits cytochrome-b divergence values comparable to the values seen between recognized species of Eumops, suggesting that this lineage represents a distinct species. The other 2 lineages are distributed in disjunct areas: Paraguay and Venezuela; and Mexico, the Caribbean, and the United States. Specimens of E. floridanus are morphologically distinct from E. glaucinus, but cannot be distinguished by examination of cytochrome-b or AFLP DNA data. We conclude that there are 4 species in the E. glaucinus complex— E. glaucinus (South America east of the Andes), E. ferox (Caribbean, Mexico, and Central America), E. floridanus in south Florida, and an unnamed taxon in western Ecuador. Speciation is a complex process and no single mechanism, model, concept, or definition is likely to cover all the diverse patterns observed.

THE FLORIDA BONNETED BAT, EUMOPS FLORIDANUS (CHIROPTERA: MOLOSSIDAE): DISTRIBUTION, MORPHOMETRICS, SYSTEMATICS, AND ECOLOGY

A review and reappraisal of bats of the genus Eumops (Chiroptera: Molossidae) reveals that considerable geographic variation is present in the bonneted bat, E. glaucinus; it is a complex consisting of .1 species. Bonneted bats in Florida are significantly larger than those in all other populations, and have proportionally shorter and deeper basisphenoid pits, the glenoid fossa is broadly triangular with rounded apices, and bacular shape differs from that in other populations. Additionally, bonneted bats in Florida have a broader palate than bats from populations in South America. Given these differences, the correct name for both Pleistocene and Recent Florida bonneted bats is Eumops floridanus (Allen, 1932). We found no geographic variation in Recent populations of Florida Eumops and little secondary sexual variation. We describe and review the distribution, morphometrics, systematics, ecology, and taxonomic history of the species, which is restricted to southern Florida. E. floridanus has one of the most restricted distributions of any bat in the New World and is one of the most critically endangered mammalian species in North America. The New World bonneted bats of the genus Eumops (Chiroptera: Molossidae) are a monophyletic lineage of 8‐10 species—E. auripendulus, E. bonariensis, E. dabbenei, E. glaucinus, E. hansae, E. maurus, E. patagonicus, E. perotis, E. trumbulli, and E. underwoodi (Eger 1977; Freeman 1981;