Tropical Andes

Tropical Andes

Bolivian tropical Andean foothills, Coroico
Highest point
Peak Huascarán
Elevation 6,768 m (22,205 ft)
Dimensions
Length 3,300 km (2,100 mi)
Geography
Country Venezuela, Colombia, Ecuador, Peru, Bolivia
Parent range Andes

The Tropical Andes is a subregion of the Andes spanning all of the Andes except the southern mediterranean and temperate zones. The Tropical Andes area spans 1,542,644 km2.

The land

The Tropical Andes is located in South America following the path of the Andes Mountains. Tropical Andes runs, mainly, through five countries, Venezuela, Colombia, Ecuador, Peru, and Bolivia. The land initially was roughly 1,258,000 km2 but has decreased to 314,500 km2, leaving 25% of the original land. Due to the massive amount of area the landscape is diverse. Diverse landscapes lead to diverse habitats and the ability to provide needed resources for many species. Diverse landscape includes snow topped mountains down to canyons and valleys. The different vegetation as altitude changes includes tropical or wet forests at 500 meters to 1,500 meters, cloud forests ranging from 800 meters to 3,500 meters, and at highest altitudes of 3,000 to 4,800 meters contain grasslands up to snow. The most diverse cloud forests found in Peru and Bolivia covers 500,000 km2. Dry forests and woodlands are also found throughout the Tropical Andes. Tropical Andes also is home to the deepest gorge in Peru at 3,223 meters deep and Lake Titicaca, the highest navigable water with the height of 3,810 meters.

Biodiversity

The Tropical Andes is a biodiversity hotspot named the "global epicenter of biodiversity" according to the Critical Ecosystem Partnership Fund.

The Tropical Andes area is an area of rich biodiversity. This location holds about 45,000 plant species of which 20,000 are endemic. There are over 3,000 vertebrate species with about 1,500 endemic. Besides plants and vertebrates, 1666 bird species, 479 reptile species, and 830 amphibian species reside in the Tropical Andes. All hotspots are important for conservation biology, but especially the tropical Andes with so many endemic species. The biodiversity within the Tropical Andes is dwindling down in numbers due to threats.

The diversity between vegetation throughout altitudes was further studied in Colombia. Chengyu Weng studied how pollen diversity is affected by different temperatures due to changing altitudes. The team studied different vegetations, the subandean forest, Andean forest, subparamo and grassparamo located in the Andes. There was more plant diversity as altitude increased throughout the vegetations. Pollen diversity positively correlated with more diversity at lower altitudes.[1] With these findings, they were able to see changes in plant diversity in the past 430000 years. During hot temperatures, pollen diversity increased at higher altitudes from plant species moving up. While cooler temperatures saw pollen diversity in lower altitudes. The study explains how temperature influences plant diversity.

Ecoregions

The ecoregions in the hotspot include:

Hotspots

A hotspot can be identified as an area with great biological diversity with high endemism. The location must also have lost a significant amount of land and threatened species according to the Essentials of Conservation Biology fourth edition. The term hotspots was used by Norman Myers written to describe ten tropical forests. The forests contained the characteristics of high levels of plant endemism and loss of habitats. Norman Myers went on to add eight more hotspots by 1990. The Conservation International reassessed Myers definition of a hotspot and by 1999 criteria for a hotspot developed to be used globally. A hotspot needs 1,500 endemic vascular plant species and a loss of at least 70 percent of original land.[2] With these criteria, twenty-five hotspots were identified in 1999 and published in the journal Nature. These twenty-five hotspots contained at least 44 percent of earth's endemics plants and 35 percent of land vertebrates. The combined area between the twenty-five hotspots used to cover 11.8 percent of land. The total amount of land has reduced from 17 million km2 to 2 million km2 or about 85% of land. Leaving this great biodiversity limited to about 1 percent of Earth's land surface.[3]

Research

There are a little over thirty hotspots now recorded and used for research. A couple other hotspots include the Caribbean Islands, Himalaya, and Japan. Due to a hotspots great diversity and endemic species, conservation biology and many other sources conduct research in these locations. Research is also needed considering the amount of threatened species in hotspots. Researches have the opportunity to preserve many species along with their habitats within hotspots. Some organizations that use hotspots for research are World Conservation Monitoring Centre, Birdlife International, Conservation International, and World Wildlife Fund. Research is also done on human impacts to the hotspots land and species that reside in them. Hotspots have actually received the most funding in the help save hotspots. Funding has estimated to $750 million accumulated over the past fifteen years. By focusing research on hotspots, many species can be helped at once.

One specific research studies fires impact on vegetation in Northern Ecuador of the Tropical Andes. This location's variety of vegetation includes different forests, land used for agricultural and páramo, or tropical alpine found at 4,500 meters. Páramo, is dominated by grasses but still high in diversity. The article Fire Ecology and Conservation in the High Tropical Andes: Observations from Northern Ecuador, looks at páramo's ability to withstand disturbances such as fire. The fact that humans have lived in this location for 7,000 years, the páramo has been through fires and grazing. The writer believes policies used to implement fire suppression are not probable or beneficiary to the plants species.[4] Policies instead should be written up according specific plant species and impact on natives living there. This is a small example of research in the Tropical Andes that could make a big impact to saving diversity.

Further research is also processed on looking into the decrease in avian populations, focusing in hotspots due to its massive diversity. The study focuses in Endemic Bird Areas or EBA in order to understand why they become extinct and possible conservation plans. As of 2003 there was 218 EBA's with over 30 percent bird species threatened. EBA's located in hotspots interfere with many human activities leading to habitat loss in 51 percent EBA's. According to the articles chart, five EBA's with habitat loss are located in the Tropical Andes. By studying the effect of human activities on EBA's that are losing avian populations, plans to help the future of other EBA's is possible. Their results showed if a species has habitat specificity and large in size the chance of extinction increases. Habitat loss will impact those with habitat specificity greatly. Conservation goals need to look into human activities and the birdj's habitat specificity in order to make a positive impact.

An example of research on a specific threatened species in the Tropical Andes is the Tremarctos ornatus, or known as Andean (or spectacled) bears. By capturing two male species, radio collars were attached in order to track and study their habits and movement. The two bears portrayed similar patterns compared to many other bear species. These findings contrasted with the belief of spectacled bears being nocturnal and no change in patterns between seasons because only slight change in temperature. The radio collars proved these spectacled bears to be diurnal. The bears were in motion from sunrise to sunset with periods of rest in-between. There was a small change in level of activity between seasons with an increase during the dry season. Due to the technology of radio collars, hypothesis about the rare spectacle bears in the Tropical Andes were tested. By knowing species habitat and lifestyle, we can better understand and help threatened species.

Rich Diversity

The Tropical Andes is said to be the most diverse hotspots. The journal Nature contained an article by Norman Myers comparing the twenty-five hotspots with land and species in 2000. At the time the Tropical Andes was recorded to have 45,000 plant species with the next closest hotspots recorded to have 25,000 plant species. Actually a sixth of all plant species can reside in the Tropical Andes. Tropical Andes also has the most endemic plant species at 20,000 and the next hotspot contains 15,000. Tropical Andes does have a lot of land compared to other hotspots, but is not the largest. Shows Tropical Andes can provide for biodiversity with diverse landscape.

Many endemic plant and animal species are currently threatened in the Tropical Andes. An example of a threatened plant species is the Andean bromelilad. Andean bromelilad is an endemic plant that takes up to 100 years to mature and a common diet for species that forage. Other plants species include many crops such as tobacco and potatoes. Some endemic animals include the Andean condor that almost became extinct from hunting. Thanks to a conservation reintroduction program, their numbers are growing. Another threatened endemic bird in the Tropical Andes is the yellow-eared parrot. One threat this species faces is the loss of the vulnerable wax palm. The yellow-eared parrot uses the wax palm for nesting and roosting. However, humans especially in Colombia are removing the vulnerable wax palm from the wild for Palm Sunday. Some conservation programs are helping the situation to educate churches to use other resources besides the vulnerable wax palm. The yellow tailed monkey is another endemic animal being endangered. They are one of the rarest mammals with a recorded population of 250 found in cloud forests of Peru. They are threatened by humans causing habitat loss and fragmentation of their habitat. Their slow maturity and low population densities do not help. Programs have tried to relocate to secondary forests, but attempts have failed. Many species reside in the Tropical Andes but threatened severely.

Threats

There are many threats that Tropical Andes face every day. One of the main threats is human activities especially with the increasing population. Some activities include mining, logging, and construction. Humans also use land for agriculture and keep relocating once the land is used up. Valleys are severely degraded due to humans living there. Hydroelectric dams have also been put in the Tropical Andes and negatively pressured cloud forests. The 25 percent of land that is protected is still poorly managed with little help from the public from lack of education. Invasive species have also been a threat to the Tropical Andes' land and species, possibly brought in from humans. A couple invasive species include the American bullfrog and certain grasses used for cattle.

Humans have the ability to cause habitat loss and habitat fragmentation for species. The forest habitats that are threatened in the Tropical Andes are modified and destroyed 30 percent faster than lower tropical areas.[5] Fragmentation causes a separation within species and decreases the diversity of genes. There is the possibility of inbreeding to increase as well. An article also looked at fragmentation causing certain phenotypes to arise in organisms. By studying feathers of 2,500 individual bird species within nine forests, observation showed asymmetry linked with fragmentation. Asymmetry was lowest if the forest continued and highest with small or medium fragmentation.[6] They suggest asymmetry of bird feathers influenced by the stress of fragmentation and changing environments. That is one outcome from fragmentation in the Tropical Andes.

A study by Niall O'Dea looks at bird communities in general and how habitat degradation impacts them. He compared the bird communities that reside in primary forests, secondary forests, edge habitat and agricultural land, all modified by humans. Most diversity was found in secondary forests and edge habitats but different species. While the agricultural land and primary forest held lowest diversity.[7] This study suggests within Andean montane forests, preserving secondary forests offers most benefit for these threatened birds.

Another serious threat to the Tropical Andes is global warming. Global warming is the effect of too many greenhouse gasses trapped in the air that hold in heat. Some locations are increasing in temperature and others decreasing. The change in temperatures has a major effect on the Tropical Andes; some say more negative then deforestation. One serious issue is the melting of the glaciers in the mountains. It is estimated that 80 percent of freshwater comes from mountains and with them melting about half of the Earths population will be affected.[8] All over the world glaciers are melting, but the mountains in the Tropical Andes are very susceptible. It is said that a quarter of the Tropical Andes glacier has already begun retreating. These glaciers make up many species water supply, and the location could be in crisis if they melt away. Glaciers in the Andes provide two main functions; decrease seasonal discharge variability and provide greater specific discharge.[9] The article by Bryan Mark, predicts an increase in discharge as glaciers melt with the ability to trace glacier water melting into watersheds using isotopes.[10] Global warming can lead to the extinction of many species especially in hotspots. A study done by Jay Malcolm predicts less than 1 percent up to 43 percent of endemic biota will become extinct due to global warming. He also believes the Tropical Andes is in the top six vulnerable hotspots with the possibility of plant extinction exceeding 2000 species.[11]

Global warming is also causing an increase in diseases among amphibians. Considering the Tropical Andes is recorded to have the most amphibians, some restricted to this location, diseases could decrease the diversity greatly. Another other factor, that 400 of the amphibian species are already threatened. These deadly fungi have actually been linked to the extinction of dinosaurs.[12] One chytrid fungus that is infecting amphibians is the batrachochytrium dendrobatidis. This fungus will impair the amphibian's skin and reduce its ability to absorb. One example of an amphibian in the Tropical Andes is the genus Atelopus with 56 of the species Critically Endangered. Due to increase in temperature, the fungus has the ability to spread rapidly and thrive on living amphibians.

A new threat that is becoming researched is the effect from nitrogen deposition. The studies done in Europe have shown diversity among plants decreased due to nitrogen deposition. Current models are estimating what could happen to hotspots across the world if nitrogen deposition keeps increasing. By comparing to past research, nitrogen deposition has already increased 50 percent since the 1990s. Estimation for the future shows an increase by 100 percent in 2050. Considering the great plant diversity in the Tropical Andes, especially so many endemics, nitrogen deposition could be a severe threat. The decrease in plant diversity could cause a chain reaction on other species that depend on the plants.

These are just few threats the Tropical Andes faces on a daily basis. The impact on the land is shown by a 75 percent decrease from original mass. Species effected are decreasing in numbers and increases the amount of species listed on the Endangered Species Act. It is worse when threatened species are endemic to the Tropical Andes. It is recorded 14 endemic mammals and 110 endemic birds are threatened in the Tropical Andes. Two species from the Tropical Andes have already become extinct.

References

  1. ↑ (Weng)
  2. ↑ (Conservation International)
  3. ↑ (Primack)
  4. ↑ (Keating)
  5. ↑ (Cuervo)
  6. ↑ (Cuervo)
  7. ↑ (O'Dea)
  8. ↑ (Mark)
  9. ↑ (Mark)
  10. ↑ (Mark)
  11. ↑ (Malcolm)
  12. ↑ (Associated Press)

Cuervo, Andrés. PersistentAssemblage and population-level consequences of forest fragmentation on bilateral asymmetry in tropical montane birds. Biological Journal of the Linnean Society; 2007, Vol. 92 Issue 1, p119-133

Keating, Philip. Fire Ecology and Conservation in the High Tropical Andes: observations from Northern Ecuador. Journal of Latin American Geography; 2007, Vol. 6 Issue 1, p43-62.

Mark, Bryan, Tracing Increasing Tropical Andean Glacier Melt with Stable Isotopes in Water. Environmental Science & Technology; 2007, Vol. 41 Issue 20, p6955-6960

Malcolm, Jay. Global Warming and Extinctions of Endemic Species from Biodiversity Hotspots. Conservation Biology; 2006, Vol. 20 Issue 2, p538-548.

Myers, Norman. Biodiversity hotspots for conservation priorities. Nature. 2000. Vol.403. p. 853-858.

Norris, Ken. Extinction processes in hot spots of avian biodiversity and the targeting of pre-emptive conservation action. The Royal Society. 2003. Vol. 271. p123-130.

O'Dea, Niall. How well do Important Bird Areas represent species and minimize conservation conflict in the tropical Andes? Diversity & Distributions; 2006, Vol. 12 Issue 2, p205-214.

O'Dea,-Niall, How resilient are Andean montane forest bird communities to habitat degradation? Biodiversity-and-Conservation. 2007. Vol.16 Issue 4. p. 1131-1159

Phoenix, Gareth. Atmospheric nitrogen deposition in world biodiversity hotspots: the need for a greater global perspective in assessing N deposition impacts. Global Change Biology. 2006. Vol.12 Issue 3 Page 470-476.

Ríos-Uzeda, B. Habitat preferences of the Andean bear (Tremarctos ornatus) in the Bolivian Andes. Journal of Zoology; Mar2006, Vol. 268 Issue 3, p271-278.

Weng, Chengyu. Response of pollen diversity to the climate-driven altitudinal shift of vegetation in the Colombian Andes. Philosophical Transactions: Biological Sciences; 2007, Vol. 362 Issue 1478, p253-262.

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