
This photo courtesy of Botany,
University of Wisconsin
Taxonomy:
Kingdom: Plantae
Phylum: Anthophyta
Class: Monocotyledonae
Subclass: Liliidae
Order: Liliales
Family: Aloeaceae
Genus: Aloe
Species: Barbadensis

Detail of flowers on
aloe plant. Photo courtesy of Agriculture,
University of Arizona
Conservation Organizations
U.S. Fish and Wildlife Service
Federal organization; maintains a list of endangered species
eligible for protection under the U.S. Endangered Species
Act
Red
List of Threatened Species
An international list of threatened and endangered species maintained
by the Species Survival Commission
CITES
List maintained by the Convention on International Trade in Endangered
Species of Wild Fauna and Flora. International agreement regulating
trade in endangered and threatened species.

This image of an aloe plant in flower is courtesy of Agriculture,
University of Arizona

A specimen of Aloe ferox,
a close relative of Aloe barbadensis,
Photo courtesy of http://www.wits.ac.za/
pharmacy/Pcognosyweb/
onographexample.htm
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Aloe Vera (Aloe barbadensis)

This photo
courtesy of http://www.blankees.com/house/plants/aloe_b.htm
Introduction
Distribution and Habitat:
A. barbadensis is native to warm,
dry regions, especially southern Europe, Asia, and Africa (University of
Wisconsin, 1999). It is cultivated almost everywhere in the world, both
as a houseplant and for its medicinal qualities. It grows best in full
sunshine and does not require much water (Denk, 2000). It does not grow
well at temperatures below 32 degrees Fahrenheit.
Physical Characteristics:
A. barbadensis can grow
up to three feet tall, although most specimens are between one and two
feet tall (Gilman, 1999). It has thick leaves that grow in a rosette
shape (Denk, 2000). The parenchyma cells
of the leaves contain large quantities of pulp . Aloe is a monocotyledon
and a member of the lily family. It is an evergreen.
Lifespan and Reproductive
Process:
Aloe is a
perennial and takes 4-5 years to mature. Plants can live and reproduce
for up to 25 years (Denk, 2000). Its tubular flowers, yellow to red in
color, grow in arrow-shaped clusters on spikes that are up to 3 feet
tall (Moore, 2001). Aloe flowers in springtime. Its fruits are small and
not particularly significant. In addition to propagating via seeds, it
can reproduce by offsets, which may take root up to 6 feet away from the
plant and grow into new plants (Moore, 2001).
Conservation Status
Aloe barbadensis is not an
endangered species. It is not listed on the United States Endangered Species Act list.
It is not listed on the internationally maintained Red List
of Threatened Species or on the CITES
list of endangered species. However, it is closely related to other
species that are endangered. According to the CITES list, every species
of the genus Aloe, besides A.
barbadensis, is threatened, and some are endangered. A. barbadensis is often cultivated
domestically and for commercial purposes, but its wild habitat is
threatened in the same way as the habitat of the other members of its
genus.
Conservation Issues
As stated
previously, A. barbadensis
itself is not an endangered species, but is closely related to species
that are. Excepting A. barbadensis,
trade is restricted in all plants of the Aloe genus due to destruction
of their natural habitat. What is this habitat? What is causing the
destruction of these plants and their habitat, and what can be done to
save it?
Aloe's Habitat:
Aloe species
primarily inhabit relatively dry, warm climates. This habitat type is
termed "Mediterranean Forests, Woodlands and Scrub" by the World
Wildlife Federation. Habitats described include the area surrounding the
Mediterranean Sea in Europe and Africa, some parts of the southwestern
United States, southern Australia, and the southern parts of Africa,
especially South Africa. Aloe is native to the Mediterranean area in
Europe and to South Africa, but has been introduced successfully in the
southern United States and Australia as well. These climates tend to
have warm, dry summers and cool, moist winters, with more precipitation
occurring during the winter. Fires occur frequently in summers, and the
species that survive are those that tolerate fire and drought well.
Nutrient density is low in these regions, and thus the habitat cannot
support large predators. Smaller animals and especially plants
predominate. These habitats have a wide variety of species that have
adapted to these unique ecological conditions. (WWF, 2001) Some,
including some species of Aloe, are endemic. Aloe albida, for example, is found
in the wild only in South Africa. (Hankey and Lotter,
2002)
Threats To Aloe:
This habitat is faced with destruction due to several factors. One
factor is deforestation and settlement of the area by humans. This
disrupts the natural balance of the area and threatens the native
species, including the aloes (WWF, 2001; Hankey and Lotter,
2002). The habitat is
also affected by burning. Species that have evolved to survive in this
habitat are naturally tolerant of regular fires. Over-burning and
under-burning, though, disrupt the ecological balance. Overburning
destroys too many of the naturally present nutrients, and underburning
leads to too many nutrients, making it easier for non-native species to
invade. (WWF, 2001). Invasive plant species pose a real problem by
crowding out the native species. Over-grazing by animals also depletes
the nutrient stores, and this also occurs when humans disrupt the
naturally occurring balance of species in the area. (WWF, 2001). Due to their
rarity, aloes and other native plants are valuable as collectors' items,
but if too many are taken from the wild, their population is threatened. (Maneveldt). Human
needs for water have led to dams being built in some areas of aloe's
habitat, and, of course, these artificially-created bodies of water
destroy the local ecosystem.
A. barbadensis, and to a lesser
extent other aloes, are also heavily used by humans. Aloe has commonly
been kept as a houseplant and the sap of the plant has been used to
soothe the pain of burns, rashes, insect bites, and other skin
irritations. The application of aloe gel to the irritated area increases
oxygen flow to the area, helping speed the process of healing. (Waltz,
2002) The sap contains many nutrients, including 7 of the 8 essential
amino acids and several vitamins. (Aloe Vera Company UK, 2002)
Aloe gel is also a common ingredient in beauty products such as soap and
shampoo (Waltz, 2002). Naturally, supplying the beauty industry requires
extensive cultivation of A.
barbadensis. This can lead to trouble if too much aloe is
harvested from the wild for commercial purposes.
Conserving Aloe:
How can
people conserve the natural habitat of A.
barbadensis and its Aloe cousins? There are several ways. First
of all, those growing aloe for commercial purposes can cultivate it in
captivity rather than harvesting from the wild. Artificially cultivated
aloe plants and seeds can be distributed for commercial and medicinal
purposes and as houseplants, and can also be reintroduced into the wild.
(WWF, 2001). The CITES treaty has restricted trade
in aloes in order to give the natural population time to regenerate. For
populations that are geographically isolated, efforts can be made to
connect the populations and facilitate gene flow, thus hopefully making
plants more hardy (Hankey and Lotter, 2002). Many steps can be taken to
protect the native environment, such as controlled burns of the area,
creating nature preserves, and educating the community about the
biodiversity of the area and how to take care of it. (WWF, 2001, Maneveldt)
Aloe species serve many
useful functions and exist in a unique habitat. Care should be taken to
make sure that the plants, their habitat, and their community do not die
out. If humans are careful with aloe's habitat, we can conserve these
extraordinary plants.
Literature
Cited
Aloe Vera Company, UK. 2002. Properties of aloe vera constituents. http://www.aloevera.co.uk/aloeprop.htm.
Accessed 3 April 2003.
Denk, Maggie. 2000. Plants with human uses. http://www.bio.gasou.edu/Bio-home/Courses/environmental/leege/BOO/ghseontheweb/
humanuses/Humanuses.htm. Accessed 30 March 2003.
Gilman, Edward F. 1999. Aloe barbadensis. http://hort.ifas.ufl.edu/shrubs/ALOBARA.PDF.
Accessed 30 March 2003.
Hankey, Andrew, and Mervyn Lotter. 2002. Cooperative conservation
initiative for the preservation of Aloe albida (Stapf.) Reynolds
Aloeaceae. (Abstract) http://www.rbg.ca/cbcn/science/abstracts/hankey1.htm.
Accessed 3 April 2003.
Maneveldt, Gavin W. Date unknown. Enviro Facts guide to Fynbos. http://www.botany.uwc.ac.za/envfacts/fynbos.
Accessed 3 April 2003.
Moore, Toni. 2001. Aloe barbadensis. http://ag.arizona.edu/pima/gardening/aridplants/Aloe_barbadensis.html.
Accessed 30 March 2003.
University of Wisconsin, Madison. 1999. Aloe barbadensis. http://botit.botany.wisc.edu/courses/tour/Roomseven-Al.html.
Accessed 30 March 2003.
Waltz, Lisa. 2002. Aloe vera-legendary healer. http://www.naturalark.com/aloevera.html.
Accessed 3 April 2003.
World Wide Fund for Nature.
2001. Mediterranean forests, woodlands, and scrub. http://www.panda.org/about_wwf/where_we_work/ecoregions/global200/
pages/habitat/habitat12.htm. Accessed 3 April 2003.
Author: Elaine Banvard
Creation/revision date: April 4, 2003
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