Thursday, April 2, 2015

Animals of the Tropical Dry Forest

          Many animal species make their home in the Tropical Dry forests. Like plants, these animals must have the ability to adapt to wet and dry seasons. Often species reproduce with the rainy seasons. Many species are also migratory. Famous large mammals, such as elephants, rhinoceros, hippopotami, and giraffes are endemic to this biome. With large herbivores come large predators, with lions, tigers, grey wolves, leopards, fossa, and jaguars all native to these areas.

Reptiles are well adapted to this biome. The animal diversity in one Mexican desert is up to 40% lizard species. Snakes and geckos are also common. Famous snakes include the venomous King cobra, fer-de-lance, and black cobra. There are less amphibian species in the dry forest, as they are generally not well adapted for the dry season. The amphibians that do live in this biome will use the small water pools at the leaf bases of bromeliads and orchids to lay their eggs and grow their tadpoles. Several bird species live in this biome, including the golden eagle, peacock, and peregrine falcon.

Various rodent and insect species are endemic to the tropical dry forest. These include the capybara and the hummingbird hawk moth. The Acacia tree has hollow thorns that house ant colonies. The ant colonies protect the tree from herbivores and other insects while the tree provides a safe home for the ants. Australia also has Tropical dry forest area. Some of the species native there are the Tasmanian devil and koala. Madagascar is part of the biome with its famous unique species such as the ring-tailed lemur.


Due to many factors, including deforestation, this biome is home to many threatened and endangered species. The black and Javan rhino, komodo dragon, sloth bear, maned wolf, tiger, and clouded leopard are all found here.

      
      
    





Plants of the Tropical Dry Forest

       The tropical dry forest biome is characterized by warm temperatures and seasonal rains. Plants and animals must be adapted to withstand downpours in the rainy seasons as well as months without rain during the dry season. To conserve water, most trees in this region are deciduous, losing their leaves in the dry season to conserve water. Some species are evergreen in the nearby tropical rainforest become deciduous when they grow in the tropical dry forest. Leaves are generally smaller and thicker. The tree canopy is shorter overall, only 10-30m tall. When the trees shed their leaves, more light reaches the ground, allowing thick underbrush to grow in the dry season. Unlike the rainforest, the trees rely mostly on animals to disperse seeds. Soils are more fertile in the dry forest than in the rainforest, but also more prone to erosion.

            Some trees native to the forest are teak, ebony, bamboo, and fig trees. The tropical dry forest is home to the Desnuda tree, also known as the Naked Indian. The Desnuda tree has green bark capable of photosynthesis when the deciduous tree sheds its leaves. When the tree is young it is spiny to prevent animals from feeding on the immature tree. The Acacia tree is also native to this area. It has large thorns which house ant colonies to deter herbivores and other insects. The Madagascar dry forest has 7 species of baobab tree. The rest of the continent of Africa only has one species. The baobab tree is believed by some natives to hold the spirits of the dead. This fact has protected sections of the Madagascar forest from deforestation. In Costa Rica, the Guanacaste tree produces large fruit to be distributed by camels and ground sloths, now extinct in that area. Domesticated herbivores have been introduced to distribute the seeds of this tree.


        Succulents and epiphytes are also well adapted to the tropical dry forest. Cacti, orchids, and  bromeliads are common. One well known species is the bridal veil stinkhorn. Bromeliads and orchids collect leaf litter and water in their leaf bases. Some amphibians use these small pools of water to reproduce.

      


Monday, March 23, 2015

Vegetation

-Mostly deciduous tree species. Many evergreen tree species of the rain forest become deciduous in this zone. 
-Growing conditions are not so optimal, so the tree canopy is lower (10-30m) than in the tropical rain forest and the trees less dense where drought is more extreme. 
-The undergrowth is dense and tangled because of greater light penetration. 
-Lianas (woody vines) are much less common than in the rain forest, not such an important growth form where light is less limiting and also perhaps highly susceptible to desiccation. 
-Drought-resistant epiphytes (orchids, bromeliads and cacti) may be abundant. 
-The trees have thicker, more ridged, bark; deeper roots without buttresses; much more variable leaves, including many compound-leaved legumes; and more species with thorns.


Climate

Temperatures are high all year, but there is a better-developed dry season than in the tropical rain forest. Evapotranspiration exceeds precipitation for enough of the year to have a significant effect on the vegetation. Edaphic conditions (dryer, better-drained soil) may produce this vegetation type in this biome.