Sylvilagus palustris hefneri
Encyclopedia
Sylvilagus palustris hefneri (Lazell, 1984), common name
Lower Keys Marsh Rabbit, is an endangered subspecies
of Marsh Rabbit
named after Playboy
founder Hugh Hefner
.
have left the rabbits with a very small home range, making them more vulnerable to threats such as pollution, vehicular road kill, and predation by stray cats. Forys and Humphrey (1999) predicted a gradual decline in S. p. hefneri abundance and extinction within 50 years (of 1995). The Lower Keys marsh rabbit population is estimated to contain approximately 100 to 300 individuals. In 2008, LaFever et al. performed viability assays to determine current extinction rates. They predicted extinction within 10 years if action is not taken immediately. They recommend urgent management of predatory stray cats, and restoration of marshes as possible solutions to reduce the extinction rate of S. p. hefneri.
in 1984 by James D. Lazell Jr, after his research was funded in part by a generous contribution from the Playboy Corporation. The Lower Keys Marsh rabbit was then named in honor of Hugh M. Hefner in recognition of the financial support received by his corporation.
castanea); succulent herbs (Borrichia
frutescens, Batis
maritima, Salicornia virginica); sedges (Cyperus
spp.); and sparse tree cover (Conocarpus erectus and Pithecellobium
guadalupense). S. p. hefneri will eat a variety of these species but they prefer Borrichia frutescens, which is common in the mid-saltmarsh area. The marsh rabbit spends most of its time feeding in the mid- and high- marsh areas.
Other possible methods into habitat conservation are:
Species-level conservation action is as follows:
Common name
A common name of a taxon or organism is a name in general use within a community; it is often contrasted with the scientific name for the same organism...
Lower Keys Marsh Rabbit, is an endangered subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
of Marsh Rabbit
Marsh Rabbit
The marsh rabbit is a small cottontail rabbit found in marshes and swamps of coastal regions of the Eastern and Southern United States. It is a strong swimmer and found only near regions of water...
named after Playboy
Playboy
Playboy is an American men's magazine that features photographs of nude women as well as journalism and fiction. It was founded in Chicago in 1953 by Hugh Hefner and his associates, and funded in part by a $1,000 loan from Hefner's mother. The magazine has grown into Playboy Enterprises, Inc., with...
founder Hugh Hefner
Hugh Hefner
Hugh Marston "Hef" Hefner is an American magazine publisher, founder and Chief Creative Officer of Playboy Enterprises.-Early life:...
.
General
S. p. hefneri was federally recognized as an endangered species on June 21, 1990. The urbanized Florida KeysFlorida Keys
The Florida Keys are a coral archipelago in southeast United States. They begin at the southeastern tip of the Florida peninsula, about south of Miami, and extend in a gentle arc south-southwest and then westward to Key West, the westernmost of the inhabited islands, and on to the uninhabited Dry...
have left the rabbits with a very small home range, making them more vulnerable to threats such as pollution, vehicular road kill, and predation by stray cats. Forys and Humphrey (1999) predicted a gradual decline in S. p. hefneri abundance and extinction within 50 years (of 1995). The Lower Keys marsh rabbit population is estimated to contain approximately 100 to 300 individuals. In 2008, LaFever et al. performed viability assays to determine current extinction rates. They predicted extinction within 10 years if action is not taken immediately. They recommend urgent management of predatory stray cats, and restoration of marshes as possible solutions to reduce the extinction rate of S. p. hefneri.
Phylogeny
The subspecies was first described in a publication in the Journal of MammalogyJournal of Mammalogy
The Journal of Mammalogy is the flagship publication of the American Society of Mammalogists. Both the society and the journal were founded in 1919. The peer-reviewed journal publishes papers about mammals throughout the world and their conservation...
in 1984 by James D. Lazell Jr, after his research was funded in part by a generous contribution from the Playboy Corporation. The Lower Keys Marsh rabbit was then named in honor of Hugh M. Hefner in recognition of the financial support received by his corporation.
Size
S. p. hefneri are small-to-medium sized of 320 to 380 mm in length and 2.20 to 3.08 pounds. Their hind feet range from 65 to 80 mm and their ears range from 45 to 62 mm in length. S. p. hefneri is the smallest of the three marsh rabbit subspecies, the others being Sylvilagus palustris paludicola and Sylvilagus palustris palustris. These rabbits do not appear to be sexually dimorphic.Appearance
The pelage of S. p. hefneri is short with dark brown fur and a greyish-white belly, and their tails are dark brown. S. p. hefneri is the smaller than the mainland marsh rabbit (S. p. palustris) and Upper Keys marsh rabbits (S. p. paludicola) and is distinguished by its dark fur. S. p. hefneri also differs from S. p. palustris and S. p. paludicola in several cranial characteristics. The Lower Keys marsh rabbit has a shorter molariform tooth row, higher and more convex frontonasal profile, broader cranium, and elongated dentary symphysis.Range
The S. p. hefneri has been isolated to the Keys by the rise in sea level and human inhabitation to the local area. This isolation may be the cause for the speciation from the Upper Keys Marsh Rabbit, Sylvilagus palustris paludicola. Forys et al. determined the habitat occupied of S. p. hefneri to be 317 ha (792.5 acres) in 1995 with 81 suitable habitats. In 1996, Forys refined the habitat to be about 253 ha (632.5 acres). An average home range of 0.32 ha was determined in 1999. This range includes a few of the larger Lower Keys, specifically, Boca Chica, Saddlebunch, Sugarloaf, and Big Pine Keys and the small islands near these Keys. From 2001 to 2005, Faulhaber et al. surveyed the predetermined habitat to establish a current habitat range. They determined the median size of occupied patches was 2.1 ha, (5.25 acres) with an interquartile range of 0.8-5.0 ha (range = 0.1-51.2 ha). This data is representative of 112 patches of occupied S. p. hefneri habitat (547.1 ha = 1367 acres (5.5 km²) total). Please note this data represents an increased search area rather than an increased rabbit number. There was a net loss (—6) in patch occupancy between the 2001-2005 and 1988-1995 survey periods. Possible reasons attributing to this loss are stray cat predation, rise in sea level, and storm surges from hurricanes.Habitat
S. p. hefneri is habitat specific choosing higher elevations within salt marsh or freshwater marsh but depend on herbaceous plants for food, cover and nesting. This vegetation includes species such as, sawgrass (Cladium jamiacense), seashore dropseed (Sporobolus virginicus), and cordgrass (Spartina spp.). Lower Keys marsh rabbits prefer areas with high amounts of clump grass, ground cover, and Borrichia frutescens present, areas closer to other existing marsh rabbit populations, and areas close to large bodies of water.Foraging
S. p. hefneri is diet specific choosing particular vegetation; however foraging strategies are not affected by sex or seasonality. The major vegetative species found in the Keys include grasses (Monanthochloe littoralis, FimbristylisFimbristylis
Fimbristylis is a genus of sedges. A plant in this genus may be known commonly as a fimbry, fimbristyle, or fringe-rush. There are 200 to 300 species distributed worldwide. Several continents have native species but many have been introduced to regions where they are not native. Many are...
castanea); succulent herbs (Borrichia
Borrichia
Borrichia is a genus of flowering plants in the daisy family, Asteraceae. It is named for Danish physician Ole Borch . Members of the genus are commonly known as seaside tansies.-Selected species:...
frutescens, Batis
Batis
Batis is a genus of two species of flowering plants, the only genus in the family Bataceae. They are halophytic plants, native to the coastal salt marshes of warm temperate and tropical America and tropical Australasia Batis (Turtleweed, Saltwort, Beachwort, or Pickleweed) is a genus of two...
maritima, Salicornia virginica); sedges (Cyperus
Cyperus
Cyperus is a large genus of about 600 species of sedges, distributed throughout all continents in both tropical and temperate regions. They are annual or perennial plants, mostly aquatic and growing in still or slow-moving water up to 0.5 m deep. The species vary greatly in size, with small species...
spp.); and sparse tree cover (Conocarpus erectus and Pithecellobium
Pithecellobium
Pithecellobium is a genus of flowering plants in the pea family, Fabaceae. The generic name is derived from the Greek words πιθηκος , meaning "ape" or "monkey," and ελλοβιον , meaning "earring," which refers to the coiled shape of the seedpods.Delimitation to the closely related Albizia is a matter...
guadalupense). S. p. hefneri will eat a variety of these species but they prefer Borrichia frutescens, which is common in the mid-saltmarsh area. The marsh rabbit spends most of its time feeding in the mid- and high- marsh areas.
Behavior
Faulhaber et al. conducted a study in 2006 to survey the diurnal habits seen in S. p. hefneri to ultimately provide conservationists with appropriate parameters for habitat extension. They determined that when S. p. hefneri were in brackish wetlands they typically clustered together in patches of saltmarsh or buttonwoods. And when in freshwater wetlands they typically clustered together in patches of freshwater hardwoods.Reproduction
S. p. hefneri produce fewer offspring, at an average of 3.7 litters per year, compared to other marsh rabbits at 5.7 litters per year. Sexual maturity in S. p. hefneri begins at about nine months of age. Researchers have found that the majority of males disperse at this time, yet females remain in their home range. S. p. hefneri are polygamous and do not display an apparent seasonal breeding pattern.Threats
S. p. hefneri is considered an endangered species and is threatened by many different sources such as habitat alteration, contaminants, vehicular traffic, dumping, poaching, domestic animals, feral hogs, fire ants, sea level rise and exotic vegetation. (14,) More than half the area of suitable S. p. hefneri habitat has been destroyed for construction of residential housing, commercial facilities, utility lines, roads, or other infrastructure in the Lower Keys. Most of the remaining suitable habitat has been degraded by exotic invasive plants, repeated mowing, dumping of trash, and off-road vehicle use. Invasive species such as the Gambian rat (Cricetomys gambianus), boa constrictors (Boa constrictor), ball pythons (Python regius), and reticulated pythons (P. reticulatus) are new threats to S. p. hefneri. However, the greatest current threat to S. p. hefneri high mortality from stray cats.Conservation
Many biologists and such have taken a close look at S. p. hefneri to determine and implement current conservation efforts. Action is currently underway at the species level and the habitat level. The most prominent method of conservation of S. p. hefneri is reintroducing the rabbits to unoccupied but potentially suitable patches Faulhaber et al. created a plan to restore or enhance key macro- and microhabitat more effectively by preventing harmful intrusion by humans, connecting isolated habitat patches, and mitigating barriers to rabbit movement. LaFever et al. demonstrate the use of population viability analysis as a conservation planning tool for reducing human wildlife conflicts. Crouse et al. conducted a genetic analysis comparing haplotypes in mitochondrial DNA to identify barriers in gene flow.Other possible methods into habitat conservation are:
- Protection of important corridors
- (Several marsh rabbit populations are linked by corridors of low marsh and mangroves. Protection of these areas will aid to avoid any negative impact on the rabbit.)
- Removal of invasive exotic vegetation
- (the invasive species kill undergrowth, destroying the rabbit’s food, shelter and nesting sites, their removal is necessary to restoring habitat)
- Fencing or barricading areas of off-road vehicle (ORV) use and/or dumping
- Improving habitat by planting or encouraging native plant species
- Monitor the status of S. p. hefneri, examine ecological processes, and increase public awareness of S. p. hefneri habitat and instill stewardship.
Species-level conservation action is as follows:
- Investigate components of both occupied and unoccupied marsh rabbit habitat and determine why rabbits are present or absent
- Maintain and improve the GIS database for S. p. hefneri information
- Conduct S. p. hefneri reintroductions from natural wild populations
- Utilize federal regulatory mechanisms for protection
- (federal activities may cause jeopardy for the total population)
- Control or eliminate free-roaming cat populations near rabbit habitat
- (Free-roaming cats are a major threat to rabbit survival, establishing a program throughout the Lower Keys to control free roaming cats will greatly increase their survival chances)
- Minimize road mortality by implementing slower speed zones and increase enforcement of existing zones, and by controlling poaching.