European tree frog
Encyclopedia
The European tree frog is the common name of Hyla arborea. The original name of this frog was Rana arborea. Some of the other common names include:
There are also five recognized subspecies of H. arborea.
. Males range from 1.3-1.8 in (32-43 mm) in length, and females range from 1.6-2.0 in (40-50 mm) in length. They are slender with long legs. Their dorsal skin is smooth, while their ventral skin is granular. Their dorsal skin can be green, gray, or tan depending on the temperature, humidity, or their mood. Their ventral skin is a whitish color, and the dorsal and ventral skin is separated by a dark brown lateral stripe that goes from the eyes to the groin. Females have a white throat, while males have a golden brown throat with large (folded) vocal sacs
. The head of H. arborea is rounded, the lip drops strongly, the pupil
has the shape of a horizontal ellipse
and the eardrum
is clearly recognizable. Also, the discs on the frog's toes, which it uses to climb trees and hedges, is a characteristic feature of H. arborea . Also, like other frogs, the hind legs are much larger and stronger than the fore legs, enabling the frog to jump rapidly.
family (Hylidae) indigenous
to Mainland Europe. H. arborea is found in Europe (except Britain and Ireland), northwest Africa, and temperate Asia to Japan. It is native to the following countries:
Albania; Armenia; Austria; Azerbaijan; Belarus; Belgium; Bosnia and Herzegovina; Bulgaria; Croatia; Czech Republic; Denmark; France; Georgia; Germany; Greece; Hungary; Italy; Liechtenstein; Lithuania; Luxembourg; Macedonia, the former Yugoslav Republic of; Moldova; Montenegro; Netherlands; Poland; Portugal; Romania; Russian Federation; Serbia; Slovakia; Slovenia; Spain; Sweden; Switzerland; Turkey; Ukraine.
It has also been introduced to the United Kingdom, and it has been reintroduced to Latvia.
H. arborea can be found in marshlands, damp meadows, reed beds, parks, gardens, vineyards, orchards, stream banks, lakeshores, or humid or dry forests. They tend to avoid dark or thick forests, and they are able to tolerate some periods of dryness; therefore, sometimes they are found in dry habitats
.
metamorphose into frogs. Metamorphosis
usually peaks from late July to early August. They are able to live for up to 15 years.
, H. arborea is “listed as Least Concern in view of its wide distribution, presumed large population, and because it is unlikely to be declining fast enough to qualify for listing in a more threatened category.” However, according to the IUCN, the population trend
of H. arborea is that the population is decreasing.
Some of the main threats to H. arborea include habitat fragmentation
and destruction, pollution of wetlands, predation from fish, capture for the pet trade, and climate change
. Besides these main threats, other possible reasons for the decline in H. arborea populations include increased UVB radiation
and local and far-ranging pesticides, fertilizers, and pollutants. It has been observed that trout are predators for H. arborea, and in Europe it has been seen that when trout are introduced into a pond, there is a significant decline in the H. arborea population.
While H. arborea are sensitive to habitat fragmentation, habitat restoration (beginning in the 1980s) has been successful to increase H. arborea populations. Besides habitat restoration, other attempts to increase H. arborea population have included building of new breeding ponds, creation of “habitat corridors to connect breeding sites”, and reintroducing H. arborea individuals. This has been successful in Sweden, Latvia, and Denmark. It has been observed that habitat protection is the most important approach to conserving H. arborea populations.
- Rainette verte (French)
- Laubfrosch (German)
- Ranita de San Antonio (Spanish)
- Obyknovennaya kvaksha (Russian)
- Brotăcel (Romanian)
- Levelibéka (lit. leaf frog) (Hungarian)
There are also five recognized subspecies of H. arborea.
Characteristics
H. arborea are small tree frogsTree frog
Hylidae is a wide-ranging family of frogs commonly referred to as "tree frogs and their allies". However, the hylids include a diversity of frog species, many of which do not live in trees, but are terrestrial or semi-aquatic.-Characteristics:...
. Males range from 1.3-1.8 in (32-43 mm) in length, and females range from 1.6-2.0 in (40-50 mm) in length. They are slender with long legs. Their dorsal skin is smooth, while their ventral skin is granular. Their dorsal skin can be green, gray, or tan depending on the temperature, humidity, or their mood. Their ventral skin is a whitish color, and the dorsal and ventral skin is separated by a dark brown lateral stripe that goes from the eyes to the groin. Females have a white throat, while males have a golden brown throat with large (folded) vocal sacs
Vocal sac
The vocal sac is the flexible membrane of skin possessed by most male frogs. The purpose of the vocal sac is usually as an amplification of their mating or advertisement call...
. The head of H. arborea is rounded, the lip drops strongly, the pupil
Pupil
The pupil is a hole located in the center of the iris of the eye that allows light to enter the retina. It appears black because most of the light entering the pupil is absorbed by the tissues inside the eye. In humans the pupil is round, but other species, such as some cats, have slit pupils. In...
has the shape of a horizontal ellipse
Ellipse
In geometry, an ellipse is a plane curve that results from the intersection of a cone by a plane in a way that produces a closed curve. Circles are special cases of ellipses, obtained when the cutting plane is orthogonal to the cone's axis...
and the eardrum
Eardrum
The eardrum, or tympanic membrane, is a thin membrane that separates the external ear from the middle ear in humans and other tetrapods. Its function is to transmit sound from the air to the ossicles inside the middle ear. The malleus bone bridges the gap between the eardrum and the other ossicles...
is clearly recognizable. Also, the discs on the frog's toes, which it uses to climb trees and hedges, is a characteristic feature of H. arborea . Also, like other frogs, the hind legs are much larger and stronger than the fore legs, enabling the frog to jump rapidly.
Distribution and habitat
H. arborea are the only members of the widespread tree frogTree frog
Hylidae is a wide-ranging family of frogs commonly referred to as "tree frogs and their allies". However, the hylids include a diversity of frog species, many of which do not live in trees, but are terrestrial or semi-aquatic.-Characteristics:...
family (Hylidae) indigenous
Endemic (ecology)
Endemism is the ecological state of being unique to a defined geographic location, such as an island, nation or other defined zone, or habitat type; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. For example, all species of lemur are endemic to the...
to Mainland Europe. H. arborea is found in Europe (except Britain and Ireland), northwest Africa, and temperate Asia to Japan. It is native to the following countries:
Albania; Armenia; Austria; Azerbaijan; Belarus; Belgium; Bosnia and Herzegovina; Bulgaria; Croatia; Czech Republic; Denmark; France; Georgia; Germany; Greece; Hungary; Italy; Liechtenstein; Lithuania; Luxembourg; Macedonia, the former Yugoslav Republic of; Moldova; Montenegro; Netherlands; Poland; Portugal; Romania; Russian Federation; Serbia; Slovakia; Slovenia; Spain; Sweden; Switzerland; Turkey; Ukraine.
It has also been introduced to the United Kingdom, and it has been reintroduced to Latvia.
H. arborea can be found in marshlands, damp meadows, reed beds, parks, gardens, vineyards, orchards, stream banks, lakeshores, or humid or dry forests. They tend to avoid dark or thick forests, and they are able to tolerate some periods of dryness; therefore, sometimes they are found in dry habitats
Habitat
* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...
.
Behavior
- Historically, tree frogs were used as barometerBarometerA barometer is a scientific instrument used in meteorology to measure atmospheric pressure. Pressure tendency can forecast short term changes in the weather...
s because they respond to approaching rain by croaking. - Depending on subspeciesSubspeciesSubspecies 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...
, temperature, humidity, and the frog's 'mood', skin colour ranges from bright to olive green, grey, brown and yellow. - H. arborea eat a variety of small arthropodsArthropodAn arthropod is an invertebrate animal having an exoskeleton , a segmented body, and jointed appendages. Arthropods are members of the phylum Arthropoda , and include the insects, arachnids, crustaceans, and others...
such as spiders, flies, beetles, butterflies, and smooth caterpillars. Its ability to take long leaps allows it to catch fast flying insects, which make up most of the food it eats. - H. arborea hibernateHibernationHibernation is a state of inactivity and metabolic depression in animals, characterized by lower body temperature, slower breathing, and lower metabolic rate. Hibernating animals conserve food, especially during winter when food supplies are limited, tapping energy reserves, body fat, at a slow rate...
in walls, cellars, under rocks, under clumps of vegetation, or buried in leaf piles or manure piles.
Reproduction
H. arborea reproduce in stagnant bodies of water, such as lakes, ponds, swamps, reservoirs, and sometimes puddles, from late March to June. They croak in the breeding season, even when migrating to their mating pools or ponds. Males will often change breeding ponds, even within the same breeding season. After a spring rain, the males will call females from low vegetation or shallow ponds. About 800 to 1,000 eggs are laid in clumps the size of a walnut. Individual eggs are about 1.5 mm in diameter. After 10-14 days, the eggs hatch. Then, after 3 months, tadpolesTadpole
A tadpole or polliwog is the wholly aquatic larval stage in the life cycle of an amphibian, particularly that of a frog or toad.- Appellation :...
metamorphose into frogs. Metamorphosis
Metamorphosis
Metamorphosis is a biological process by which an animal physically develops after birth or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and differentiation...
usually peaks from late July to early August. They are able to live for up to 15 years.
Conservation status
According to the IUCN Red List of Endangered SpeciesIUCN Red List
The IUCN Red List of Threatened Species , founded in 1963, is the world's most comprehensive inventory of the global conservation status of biological species. The International Union for Conservation of Nature is the world's main authority on the conservation status of species...
, H. arborea is “listed as Least Concern in view of its wide distribution, presumed large population, and because it is unlikely to be declining fast enough to qualify for listing in a more threatened category.” However, according to the IUCN, the population trend
Population growth
Population growth is the change in a population over time, and can be quantified as the change in the number of individuals of any species in a population using "per unit time" for measurement....
of H. arborea is that the population is decreasing.
Some of the main threats to H. arborea include habitat fragmentation
Habitat fragmentation
Habitat fragmentation as the name implies, describes the emergence of discontinuities in an organism's preferred environment , causing population fragmentation...
and destruction, pollution of wetlands, predation from fish, capture for the pet trade, and climate change
Climate change
Climate change is a significant and lasting change in the statistical distribution of weather patterns over periods ranging from decades to millions of years. It may be a change in average weather conditions or the distribution of events around that average...
. Besides these main threats, other possible reasons for the decline in H. arborea populations include increased UVB radiation
Ultraviolet
Ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...
and local and far-ranging pesticides, fertilizers, and pollutants. It has been observed that trout are predators for H. arborea, and in Europe it has been seen that when trout are introduced into a pond, there is a significant decline in the H. arborea population.
While H. arborea are sensitive to habitat fragmentation, habitat restoration (beginning in the 1980s) has been successful to increase H. arborea populations. Besides habitat restoration, other attempts to increase H. arborea population have included building of new breeding ponds, creation of “habitat corridors to connect breeding sites”, and reintroducing H. arborea individuals. This has been successful in Sweden, Latvia, and Denmark. It has been observed that habitat protection is the most important approach to conserving H. arborea populations.