Fragile habitats to invasive species

The most isolated Island in the world - Bouvet Island
 (Photo: Dolph kessler)

Basically all habitats are endangered by the introduction of species but in fact there are some which are more fragile.

Islands - Generally, islands species have limited population because of the island capacity, the geographic distribution is also limited and these species are less adapted to new predators. In result of that, these vulnerable species have more chance to extinction (Vitousek, 1997).

In islands the species evolved extreme vulnerable habits without presence of predators. The introduction of common predators such as snakes, cats, lizards or rats can result in extinction of species as happened in Fernando de Noronha where the endemic Noronhomys vespuccii was extinct by invasive species.

Rivers and Lakes - The introduction of exotic animals in rivers or lakes can result in catastrophes. The introduction of Lates niloticus in Victoria's lake in Africa to develop the fishing industry had catastrophic results. Approximately 70% of native species in the lake were extinct or close to be extinct. In consequence of this, the main source of protein and food to those communities around the lake there is no longer (Ogutu- Ohwayo, 1990; Kaufman, 1992).

Fishing at lake Victoria in Africa.

Works Cited:

KAUFMAN, L. Catastrophic change in species-rich freshwater ecosystems: the lessons of Lake Victoria. BioScience, v. 42, p. 846, 1992. 

OGUTU-OHWAYO, R. The decline of the native fishes of lakes Victoria and Kyoga (East Africa) and the impact of introduced species, especially the Nile perch, Lates niloticus, and the Nile tilapia, Oreochromis niloticus. Environmental Biology of Fishes, 27, p. 81–96. 1990. 

VITOUSEK, P. Diversidade e invasões biológicas de ilhas oceânicas. In: E. O. Wilson (Ed.), Biodiversidade. Rio de Janeiro: Nova Fronteira. 1997.

Economic impacts

I would like to write more about Fernando de Noronha but I saw some awesome articles showing the economic impacts of invasive/exotic species. As we know, "money moves the world" and now I will present some data that may make the eyes of investors and authorities around the world turn to the environment, considering that the ecological appeal does not always work.

Image found in Google Images

In 2005 in the United States some researchers estimated that more than 120 billion of dollars would be spent because of Invasive species (Pimentel et al., 2005).

In Brazil is estimated by the scientists that more than 42,6 billion of dollars is spent every year just related with algae, mites and invasive plants in crops (Pimentel et al., 2001).

Around the world the losses in agriculture were estimated in 248 billion of dollars per year (Bright, 1999), today this number can be biggest.

Actually, if we consider the money used to avoid disease propagation such as dengue these numbers are inestimable whereas they looked only at agriculture.




Works cited:

BRIGHT, C. Invasive species: pathogens of globalization. Foreign Policy Fall, v. 1999, p. 50–64, 1999.

PIMENTEL, D.; McNAIR, S.;, JANECKA, J.; WIGHTMAN, J.; SIMMONDS, C.; O’CONNELL, C.; WONG, E.; RUSSEL, L.; ZERN, J.; AQUINO, T.; TSOMONDO, T. Economic and environmental threats of alien plant, animal, and microbe invasions. Agriculture, Ecosystems e Environment, v. 84, p. 1–20, 2001.

PIMENTEL, D.; ZUNIGA, R.; MORRISON, D. Update on the environmental and economic costs 
associated with alien-invasive species in the United States. Ecological Economics, v. 52, 2005. 

Noronha and the Teju lizard

Salvador Merianae, Photo - David G. Barkasy

            This post is going to inform about the introduction of the Teju lizard (Tupinambis merianae) in Fernando de Noronha.

            The Tupinambis merianae (now know as Salvator merianae) is a Teiidae lizard. In South- eastern Brazil this large lizard is reported to prey on invertebrates and vertebrates, and to feed on carrion, fruits, and fungi (Kiefer and Sazima, 2002; Marques and Sazima 2004; Toledo, Prado and Andrade 2004; Maffei et al., 2009). Also, because of they size S. merianae is able to attack even large mammals (Sazima and Haddad, 1992; Martuscelli and Olmos, 1996; Cicchi, 2006). 

            In 1950s Noronha was used as  a military base and 2 couples of Teju were introduced in the Island trying to control the infestation of rats (That were also introduced). However, these lizards are diurnal animals and mice are active at night (Mathews & Brand, 2005).
           "The lizard found an abundant food supply, however, in the form of the eggs of seabirds nesting on the island. Its effect on ground-nesting birds was so severe that they were forced to move to smaller islands nearby. The combined impact of predation followed by a reduction in breeding space may well have caused a decline in the population of some bird species. In the meantime, the lizard population has steadily grown, and by 2004 was estimated at between 2 000 and 8 000 on the 17 km2 island" (Mathews & Brand, 2005).

            This example shows how unpredictable is the nature and how animals will behave in a new environment, this species has caused an incalculable damage to local fauna, such as birds and turtles.



Works Cited:

Cicchi, P.J.P. (2006): Tupinambis merianae (Tegu). Diet. Herpetological Review 37: 347.

Kiefer, M.C, Sazima, I. (2002): Diet of juvenile tegu lizard Tupinambis merianae (Teiidae) in southeastern Brazil. Amphibia-Reptilia 23: 105-108.

Maffei, F., Ubaid, F.K., Medolago, C.A.B., Jim, J. (2009): Tupinambis merianae (Common Tegu). Diet. Herpetological Diet. Herpetological Review 40: 439.

Marques, O.A.V., Sazima, I. (2004): História natural dos répteis da estação Ecológica Juréia-Itatins. In: Estação Ecológica Juréia-Itatins, p. 257-277. Marques, O.A.V., Duleba, W., Eds., Ribeirão Preto, Holos.

Mathews, S., Brand, K. (2005): South America invaded : the growing danger of invasive alien species / edited by Sue Matthews and Kobie Brand. 

Martuscelli, P., Olmos, F. (1996): Tupinambis teguixin (Common Tegu). Foraging. Herpetological Review 27: 21.

Olson SL  (1981)  Natural history of vertebrates on the Brazilian Islands of the Mid south Atlantic.  National Geographic Society Research Reports 13: 481-492.

Oren DC  (1984)  Resultados de uma nova expedição zoológica a Fernando de oronha.  Boletim do Museu Paraense Emilio Goeldi, Zoologia 1: 19-44.

Sazima, I., Haddad, C.F.B. (1992): Répteis da Serra do Japi: notas sobre história natural. In: História Natural da Serra do Japi, p. 221-236. Morellato, L.P.C., Ed., Campinas, Editora da Unicamp/FAPESP.

Sazima, I., Haddad, C.F.B. (2003): Range of animal food types recorded for the tegu lizard (Salvator 
merianae) at an urban park in South-eastern Brazil. Herpetology Notes, volume 6: 427-430.

Toledo, L.F., Prado, C.P.A., Andrade, D.V. (2004): Tupinambis merianae (Tegu Lizard). Fungivory. Herpetological Review 35: 173-174.

Fernando de Noronha and the Vespucci's Rat

Archipelago of Fernando de Noronha.

         


       I'll start posting something in my comfortable zone. Let's talk about Fernando de Noronha and the impacts of non-native species there. Fernando de Noronha is a group of islands with no more than 2 thousand inhabitants and one of the most touristic places in the world.

• What happened in Noronha?

Cranium of Noronhomys vespuccii.

      In 1503, when the Italian explorer Amerigo Vespucci arrived in Noronha he may have seen a species that today is known as Noronhomys vespuccii, a enormous species of rat that today are extinct. After the first explorers introduced Mus musculus and Felis catus the population of Vespucci's Rat decreased drastically, years later with the introduction of Rattus rattus the competition became too wild and this species disappeared.

     The fossils of this species were found in 1973 and described by Carleton and Olson in 1999. The evolutionary history of this animals suggest that their ancestors were semi-aquatic animals and Carleton and Olson (1999) suggest that the characteristics were lost when the progenitors of the Vespucci's Rat became stranded on a small oceanic island. This new characteristic probably appeared because of the natural selection in a long process (maybe million of years), but the presence of invasive species destroyed it in centuries. 

        To sum up, the anthropogenic alteration is cruel mainly to native island species as Noronhomys vespuccii. Now, the effects of the most invasive species in the world, known as Homo sapiens is incalculable and the alterations in fragile ecosystems is deteriorating more and more the environment. 

Work cited (description of new genus and species):

Carleton, M.D. and Olson, S.L. 1999. Amerigo Vespucci and the rat of Fernando de Noronha: a new genus and species of Rodentia (Muridae, Sigmodontinae) from a volcanic island off Brazil's continental shelf. American Museum Novitates 3256:1–59.