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El Graduado
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Agilis,
I guess we need to determine the definition of “invasive species”.
The USDA’s Definitions Subcommittee of the Invasive Species Advisory Committee (ISAC) produced a definition (approved by ISAC Apr 27, 2006) as “an alien species whose introduction does or is likely to cause economic or environmental harm or harm to human health”.
Encyclopedia Britannica defines it as “any non-native species that significantly modifies or disrupts the ecosystems it colonizes. Such species may arrive in new areas through natural migration, but they are often introduced by the activities of other species”.
The US Geological Survey (USGS) says “An invasive species is an introduced, nonnative organism (disease, parasite, plant, or animal) that begins to spread or expand its range from the site of its original introduction and that has the potential to cause harm to the environment, the economy, or to human health”.
These definitions and others put heavy emphasis on the idea of the disruption or harm caused to the area the “invasive species” invades. Not so much emphasis is put on how they got to be where they invaded.
I subscribe to those ideas. I distinguish between “introduced” and “invasive” species. I say (in my new book) the coconut tree is an introduced species in Cozumel. The Casuarina Pine is an invasive species. The dog wasn’t invasive when it was a domestic household animal, but when they turn feral, they are.
Given the definitions to which I subscribe, Man cannot be an invasive species. He is the one that gauges whether or not a species is harmful to him or his environment.
The Cozumel Fox arrived on Cozumel sometime after 125,000 years ago, the last time Cozumel was underwater.
Were there tropical forests on Cozumel before people arrived? Yes. There is no evidence of man on Cozumel prior to 3,000 years ago, though he may have arrived as early as 13,000 years ago. To what extent has the presence of humans changed Cozumel from what it was only a few thousand years ago into what it is now? Not much. Although the Maya cultivated much of Cozumel, those parts all returned to their natural state. Historically, hurricanes have done more damage to the island’s ecosystem than man. The only animals the ancient Maya killed for food that are not around now are the Cozumel Island Fox (may now be extinct), and the Caribbean Monk Seal (last seen in 1952). That is from osteological evidence produced from many archaeological excavations and studies on Cozumel. Other native Cozumel animals are on their way out (think the endemic Cozumel Harvest Mouse and other native rodents), thanks in part to the invasive boa. No boa vertebra showed up in any of those archaeological studies.
I guess we need to determine the definition of “invasive species”.
The USDA’s Definitions Subcommittee of the Invasive Species Advisory Committee (ISAC) produced a definition (approved by ISAC Apr 27, 2006) as “an alien species whose introduction does or is likely to cause economic or environmental harm or harm to human health”.
Encyclopedia Britannica defines it as “any non-native species that significantly modifies or disrupts the ecosystems it colonizes. Such species may arrive in new areas through natural migration, but they are often introduced by the activities of other species”.
The US Geological Survey (USGS) says “An invasive species is an introduced, nonnative organism (disease, parasite, plant, or animal) that begins to spread or expand its range from the site of its original introduction and that has the potential to cause harm to the environment, the economy, or to human health”.
These definitions and others put heavy emphasis on the idea of the disruption or harm caused to the area the “invasive species” invades. Not so much emphasis is put on how they got to be where they invaded.
I subscribe to those ideas. I distinguish between “introduced” and “invasive” species. I say (in my new book) the coconut tree is an introduced species in Cozumel. The Casuarina Pine is an invasive species. The dog wasn’t invasive when it was a domestic household animal, but when they turn feral, they are.
Given the definitions to which I subscribe, Man cannot be an invasive species. He is the one that gauges whether or not a species is harmful to him or his environment.
The Cozumel Fox arrived on Cozumel sometime after 125,000 years ago, the last time Cozumel was underwater.
Were there tropical forests on Cozumel before people arrived? Yes. There is no evidence of man on Cozumel prior to 3,000 years ago, though he may have arrived as early as 13,000 years ago. To what extent has the presence of humans changed Cozumel from what it was only a few thousand years ago into what it is now? Not much. Although the Maya cultivated much of Cozumel, those parts all returned to their natural state. Historically, hurricanes have done more damage to the island’s ecosystem than man. The only animals the ancient Maya killed for food that are not around now are the Cozumel Island Fox (may now be extinct), and the Caribbean Monk Seal (last seen in 1952). That is from osteological evidence produced from many archaeological excavations and studies on Cozumel. Other native Cozumel animals are on their way out (think the endemic Cozumel Harvest Mouse and other native rodents), thanks in part to the invasive boa. No boa vertebra showed up in any of those archaeological studies.
