9. A Comparative Review of Forest Dynamics
197
insect outbreaks appear to be of lesser ecological significance to coastal
forests .
Human Modifications of Disturbance Regimes
Impacts of Introduced Animals
Although European settlement prior to the mid-nineteenth century was
rare in the rainforest districts of Chile and Argentina, domestic livestock
arrived at least two centuries earlier as escapees from coastal settlements
(Fonck, 1900; Martinic, 1985). Throughout southern Chile and Argentina,
forests have been heavily used to graze livestock for at least 60 years and
in many cases for over a century (Cunill, 1974; Goodall, 1979; Roig et al.,
1985). Although there are some inaccessible areas where livestock are not
found, these account for only a small percentage of rainforest area.
Exotic deer (mostly the red deer, Cervus elaphus, but also fallow deer,
Dama dama, and axis deer, Axis axis), upon which a lucrative sport
hunting industry depends, have attained high population densities and
have had a deleterious impact on native vegetation in southern Chile
and particularly in Argentina (Ramilo, 1985; Ramirez, Godoy, Eldridge,
& Pacheco, 1985; Veblen, Mermoz, Martin, & Ramilo, 1989b). Deer
and livestock have an inhibitory effect on the regeneration of common
arboreal species (Martin, Mermoz, & Gallopfn, 1985; Ramirez et al.,
1981; Veblen et al., 1989b; Veblen, Mermoz, Martin, & Kitzberger,
1992b).
European hares (Lepus capensis) and wild boars (Sus scrofa) have
colonized nearly all suitable habitats of mainland Patagonia (Daciuk,
1978). Because of their rooting activities, wild boars are responsible for
localized alteration of grasslands and forest openings, especially in the
Andean parts of the Argentine provinces of Rio Negro and Chubut
(Daciuk, 1978). European hares occur throughout continental Patagonia
primarily in grasslands where they often attain high population densities
and have had a significant impact on the vegetation . Although hares and
boars do not occur on Tierra del Fuego, introduced rabbits (Oryctolagus
cuniculus) and beavers (Castor canadensis) are severe pests there
(Goodall , 1979; Lizarralde, Escobar, & Biancciotto, 1990). Their damage
includes both cutting of trees and flooding of large areas of Nothofagus
forest.
In North America, there are few instances of exotic introductions of
herbivores that have been so successful as to significantly affect native
vegetation. Many huntable species have been introduced to regions that
are slightly out of their natural range. Impacts of species introductions are
of much less importance in North America than in South America. For
example mountain goats were introduced into the Olympic Mountains
197
insect outbreaks appear to be of lesser ecological significance to coastal
forests .
Human Modifications of Disturbance Regimes
Impacts of Introduced Animals
Although European settlement prior to the mid-nineteenth century was
rare in the rainforest districts of Chile and Argentina, domestic livestock
arrived at least two centuries earlier as escapees from coastal settlements
(Fonck, 1900; Martinic, 1985). Throughout southern Chile and Argentina,
forests have been heavily used to graze livestock for at least 60 years and
in many cases for over a century (Cunill, 1974; Goodall, 1979; Roig et al.,
1985). Although there are some inaccessible areas where livestock are not
found, these account for only a small percentage of rainforest area.
Exotic deer (mostly the red deer, Cervus elaphus, but also fallow deer,
Dama dama, and axis deer, Axis axis), upon which a lucrative sport
hunting industry depends, have attained high population densities and
have had a deleterious impact on native vegetation in southern Chile
and particularly in Argentina (Ramilo, 1985; Ramirez, Godoy, Eldridge,
& Pacheco, 1985; Veblen, Mermoz, Martin, & Ramilo, 1989b). Deer
and livestock have an inhibitory effect on the regeneration of common
arboreal species (Martin, Mermoz, & Gallopfn, 1985; Ramirez et al.,
1981; Veblen et al., 1989b; Veblen, Mermoz, Martin, & Kitzberger,
1992b).
European hares (Lepus capensis) and wild boars (Sus scrofa) have
colonized nearly all suitable habitats of mainland Patagonia (Daciuk,
1978). Because of their rooting activities, wild boars are responsible for
localized alteration of grasslands and forest openings, especially in the
Andean parts of the Argentine provinces of Rio Negro and Chubut
(Daciuk, 1978). European hares occur throughout continental Patagonia
primarily in grasslands where they often attain high population densities
and have had a significant impact on the vegetation . Although hares and
boars do not occur on Tierra del Fuego, introduced rabbits (Oryctolagus
cuniculus) and beavers (Castor canadensis) are severe pests there
(Goodall , 1979; Lizarralde, Escobar, & Biancciotto, 1990). Their damage
includes both cutting of trees and flooding of large areas of Nothofagus
forest.
In North America, there are few instances of exotic introductions of
herbivores that have been so successful as to significantly affect native
vegetation. Many huntable species have been introduced to regions that
are slightly out of their natural range. Impacts of species introductions are
of much less importance in North America than in South America. For
example mountain goats were introduced into the Olympic Mountains