2003
Levine, Jonathan M.; Vilà, Montserrat; D’Antonio, Carla M.; Dukes, Jeffrey S.; Grigulis, Karl; Lavorel, Sandra
Mechanisms underlying the impacts of exotic plant invasions Journal Article
In: Proceedings of the Royal Society, vol. 270, no. 1517, pp. 775-781, 2003, ISSN: 0962-8452.
Abstract | Links | BibTeX | Tags: biological invasions, community structure, ecosystem processes, exotic plants, impact
@article{Levine2003c,
title = {Mechanisms underlying the impacts of exotic plant invasions},
author = {Jonathan M. Levine and Montserrat Vilà and Carla M. D'Antonio and Jeffrey S. Dukes and Karl Grigulis and Sandra Lavorel},
url = {https://angelo.berkeley.edu/wp-content/uploads/sites/59/Review-Paper.-Mechanisms-Underlying-the-Impacts-of-Exotic-Plant-Invasions_Levine_2003.pdf},
doi = {10.1098/rspb.2003.2327},
issn = {0962-8452},
year = {2003},
date = {2003-04-22},
journal = {Proceedings of the Royal Society},
volume = {270},
number = {1517},
pages = {775-781},
abstract = {Although the impacts of exotic plant invasions on community structure and ecosystem processes are well appreciated, the pathways or mechanisms that underlie these impacts are poorly understood. Better exploration of these processes is essential to understanding why exotic plants impact only certain systems, and why only some invaders have large impacts. Here, we review over 150 studies to evaluate the mechanisms underlying the impacts of exotic plant invasions on plant and animal community structure, nutrient cycling, hydrology and fire regimes. We find that, while numerous studies have examined the impacts of invasions on plant diversity and composition, less than 5% test whether these effects arise through competition, allelopathy, alteration of ecosystem variables or other processes. Nonetheless, competition was often hypothesized, and nearly all studies competing native and alien plants against each other found strong competitive effects of exotic species. In contrast to studies of the impacts on plant community structure and higher trophic, levels, research examining impacts on nitrogen cycling, hydrology and fire regimes is generally highly mechanistic, often motivated by specific invader traits. We encourage future studies that link impacts on community structure to ecosystem processes, and relate the controls over invasibility to the controls over impact.},
keywords = {biological invasions, community structure, ecosystem processes, exotic plants, impact},
pubstate = {published},
tppubtype = {article}
}
Although the impacts of exotic plant invasions on community structure and ecosystem processes are well appreciated, the pathways or mechanisms that underlie these impacts are poorly understood. Better exploration of these processes is essential to understanding why exotic plants impact only certain systems, and why only some invaders have large impacts. Here, we review over 150 studies to evaluate the mechanisms underlying the impacts of exotic plant invasions on plant and animal community structure, nutrient cycling, hydrology and fire regimes. We find that, while numerous studies have examined the impacts of invasions on plant diversity and composition, less than 5% test whether these effects arise through competition, allelopathy, alteration of ecosystem variables or other processes. Nonetheless, competition was often hypothesized, and nearly all studies competing native and alien plants against each other found strong competitive effects of exotic species. In contrast to studies of the impacts on plant community structure and higher trophic, levels, research examining impacts on nitrogen cycling, hydrology and fire regimes is generally highly mechanistic, often motivated by specific invader traits. We encourage future studies that link impacts on community structure to ecosystem processes, and relate the controls over invasibility to the controls over impact.
1999
Levine, Jonathan M.; D’Antonio, Carla M.
Elton revisited: a review of evidence linking diversity and invasibility Journal Article
In: Oikos, vol. 87, no. 1, pp. 15-26, 1999, ISSN: 0030-1299, (File size exceeds maximum allowable for Angelo’s website. Please see the attached stable link for PDF.).
Abstract | Links | BibTeX | Tags: biodiversity, biological invasions, California, COMMUNITIES, competition, exotic plants, grassland, introduced Hawaiian avifauna, New Zealand, positive interactions, riparian zones
@article{Levine1999,
title = {Elton revisited: a review of evidence linking diversity and invasibility},
author = {Jonathan M. Levine and Carla M. D'Antonio},
url = {http://www.jstor.org/stable/3546992},
doi = {10.2307/3546992},
issn = {0030-1299},
year = {1999},
date = {1999-10-00},
journal = {Oikos},
volume = {87},
number = {1},
pages = {15-26},
abstract = {It is commonly believed that diverse communities better resist invasion by exotic species than do simple communities. We examined the history of this notion, and evaluated theoretical and empirical work linking diversity and invasions. We found that much of the historical work that has contributed to the perception that diverse communities are less invasible, including Elton's observations and MacArthur's species-packing and diversity-stability models, is based on controversial premises. Nevertheless, more recent theoretical studies consistently supported the predicted negative relationship between diversity and invasibility. The results of empirical studies, however, were decidedly mixed. Constructed community studies directly manipulating diversity found both positive and negative effects of diversity on invasibility in both field and microcosm settings. Other empirical studies tracking the assembly of ecological communities generally suggested that communities decline in invasibility as species accumulate over time, though the role of diversity itself was often ambiguous. Studies of the spatial correlation between diversity and invasion and studies experimentally adding invaders to natural systems indicated that diverse communities tend to be more invasible. We argue that these results most likely reflect environmental factors spatially covarying with diversity in natural communities (e.g. resources, disturbance), and not the effects of diversity itself as uncovered by constructed community studies. Nevertheless, the consistent positive relationship between exotic species abundance and resident species diversity found in spatial pattern studies suggests that invaders and resident species are more similar than often believed, and the implications of this for theories of invasion are discussed.},
note = {File size exceeds maximum allowable for Angelo's website. Please see the attached stable link for PDF.},
keywords = {biodiversity, biological invasions, California, COMMUNITIES, competition, exotic plants, grassland, introduced Hawaiian avifauna, New Zealand, positive interactions, riparian zones},
pubstate = {published},
tppubtype = {article}
}
It is commonly believed that diverse communities better resist invasion by exotic species than do simple communities. We examined the history of this notion, and evaluated theoretical and empirical work linking diversity and invasions. We found that much of the historical work that has contributed to the perception that diverse communities are less invasible, including Elton’s observations and MacArthur’s species-packing and diversity-stability models, is based on controversial premises. Nevertheless, more recent theoretical studies consistently supported the predicted negative relationship between diversity and invasibility. The results of empirical studies, however, were decidedly mixed. Constructed community studies directly manipulating diversity found both positive and negative effects of diversity on invasibility in both field and microcosm settings. Other empirical studies tracking the assembly of ecological communities generally suggested that communities decline in invasibility as species accumulate over time, though the role of diversity itself was often ambiguous. Studies of the spatial correlation between diversity and invasion and studies experimentally adding invaders to natural systems indicated that diverse communities tend to be more invasible. We argue that these results most likely reflect environmental factors spatially covarying with diversity in natural communities (e.g. resources, disturbance), and not the effects of diversity itself as uncovered by constructed community studies. Nevertheless, the consistent positive relationship between exotic species abundance and resident species diversity found in spatial pattern studies suggests that invaders and resident species are more similar than often believed, and the implications of this for theories of invasion are discussed.
1997
Kotanen, Peter M.
Effects of experimental soil disturbance on revegetation by natives and exotics in coastal Californian meadows Journal Article
In: Journal of Applied Ecology, vol. 34, no. 3, pp. 631-644, 1997, ISSN: 0021-8901.
Abstract | Links | BibTeX | Tags: biological invasions, colonization, grasses, introductions
@article{Kotanen1997,
title = {Effects of experimental soil disturbance on revegetation by natives and exotics in coastal Californian meadows},
author = {Peter M. Kotanen},
url = {https://angelo.berkeley.edu/wp-content/uploads/sites/59/Kotanen_AppliedEcology1997.pdf},
issn = {0021-8901},
year = {1997},
date = {1997-09-00},
journal = {Journal of Applied Ecology},
volume = {34},
number = {3},
pages = {631-644},
abstract = {1. Disturbance is widely believed to facilitate invasions by exotic plants, but is also important for the persistence of many native species. Here, I report the results of a series of field experiments designed to investigate the effects of soil disturbance on natives and aliens in Californian grassland vegetation. I also compare the effects of different types of soil disturbance to establish whether some favour aliens to a greater degree than others.
2. In two experiments, conducted at different locations, three types of soil disturbance (excavation, burial and simulated gopher mounds) were created, and their revegetation was compared with changes in undisturbed control plots over the next three years. A third experiment was used to provide data on the effects of soil disturbance on soil temperature, moisture and KCl-extractable nitrogen.
3. Disturbance affected both soil temperature and chemistry. Buried plots contained the most KCl-extractable nitrogen, and were also the warmest. Effects on soil moisture were relatively small.
4. Initially, most disturbances greatly reduced the numerical abundance both of groups dominated by natives (perennial graminoids and bulbs) and of groups dominated by aliens (annual graminoids). Disturbance also reduced maximal (summer) species richness, but in some cases increased the fraction of richness contributed by natives.
5. In subsequent years, richness rebounded as natives and exotics re-invaded. Native bulbs and perennial graminoids were slow to recover; instead, most disturbances sr increasingly became numerically dominated by exotic annual grasses, accentuating the effects of a multi-year drought.
6. The differing effects of experimental disturbances on aliens and natives can best be explained by considering relationships between sources of propagules, life histories and geographical origins.
7. Some types of disturbance were less damaging to native-dominated groups than others, but most ultimately favoured exotics. Consequently, it may be difficult to develop management strategies that preserve the diversity of disturbance-dependent natives while still excluding weedy aliens.},
keywords = {biological invasions, colonization, grasses, introductions},
pubstate = {published},
tppubtype = {article}
}
1. Disturbance is widely believed to facilitate invasions by exotic plants, but is also important for the persistence of many native species. Here, I report the results of a series of field experiments designed to investigate the effects of soil disturbance on natives and aliens in Californian grassland vegetation. I also compare the effects of different types of soil disturbance to establish whether some favour aliens to a greater degree than others.
2. In two experiments, conducted at different locations, three types of soil disturbance (excavation, burial and simulated gopher mounds) were created, and their revegetation was compared with changes in undisturbed control plots over the next three years. A third experiment was used to provide data on the effects of soil disturbance on soil temperature, moisture and KCl-extractable nitrogen.
3. Disturbance affected both soil temperature and chemistry. Buried plots contained the most KCl-extractable nitrogen, and were also the warmest. Effects on soil moisture were relatively small.
4. Initially, most disturbances greatly reduced the numerical abundance both of groups dominated by natives (perennial graminoids and bulbs) and of groups dominated by aliens (annual graminoids). Disturbance also reduced maximal (summer) species richness, but in some cases increased the fraction of richness contributed by natives.
5. In subsequent years, richness rebounded as natives and exotics re-invaded. Native bulbs and perennial graminoids were slow to recover; instead, most disturbances sr increasingly became numerically dominated by exotic annual grasses, accentuating the effects of a multi-year drought.
6. The differing effects of experimental disturbances on aliens and natives can best be explained by considering relationships between sources of propagules, life histories and geographical origins.
7. Some types of disturbance were less damaging to native-dominated groups than others, but most ultimately favoured exotics. Consequently, it may be difficult to develop management strategies that preserve the diversity of disturbance-dependent natives while still excluding weedy aliens.
2. In two experiments, conducted at different locations, three types of soil disturbance (excavation, burial and simulated gopher mounds) were created, and their revegetation was compared with changes in undisturbed control plots over the next three years. A third experiment was used to provide data on the effects of soil disturbance on soil temperature, moisture and KCl-extractable nitrogen.
3. Disturbance affected both soil temperature and chemistry. Buried plots contained the most KCl-extractable nitrogen, and were also the warmest. Effects on soil moisture were relatively small.
4. Initially, most disturbances greatly reduced the numerical abundance both of groups dominated by natives (perennial graminoids and bulbs) and of groups dominated by aliens (annual graminoids). Disturbance also reduced maximal (summer) species richness, but in some cases increased the fraction of richness contributed by natives.
5. In subsequent years, richness rebounded as natives and exotics re-invaded. Native bulbs and perennial graminoids were slow to recover; instead, most disturbances sr increasingly became numerically dominated by exotic annual grasses, accentuating the effects of a multi-year drought.
6. The differing effects of experimental disturbances on aliens and natives can best be explained by considering relationships between sources of propagules, life histories and geographical origins.
7. Some types of disturbance were less damaging to native-dominated groups than others, but most ultimately favoured exotics. Consequently, it may be difficult to develop management strategies that preserve the diversity of disturbance-dependent natives while still excluding weedy aliens.
Kupferberg, Sarah J.
Bullfrog (Rana catesbeiana) invasion of a California river: the role of larval competition Journal Article
In: Ecology, vol. 78, no. 6, pp. 1736-1751, 1997, ISSN: 0012-9658.
Abstract | Links | BibTeX | Tags: algae, biological invasions, California, grazing, Hyla regilla, Rana boylii, Rana catesbeiana, rivers, size-structured competition
@article{Kupferberg1997,
title = {Bullfrog (Rana catesbeiana) invasion of a California river: the role of larval competition},
author = {Sarah J. Kupferberg},
url = {https://angelo.berkeley.edu/wp-content/uploads/sites/59/Kupferberg_Ecology1997.pdf},
issn = {0012-9658},
year = {1997},
date = {1997-09-00},
journal = {Ecology},
volume = {78},
number = {6},
pages = {1736-1751},
abstract = {I studied the invasion of Rana catesbeiana (the bullfrog) into a northern California river system where bullfrogs are not native. Native yellow-legged frogs, Rana boylii, a species of special concern, were almost an order of magnitude less abundant in reaches where bullfrogs were well established. I assessed the potential role of larval competition in contributing to this displacement in a series of field manipulations of tadpole density and species composition. The impact of R. catesbeiana on native tadpoles in the natural community agreed with the outcome of more artificial experiments testing pairwise and three-way interactions. In 2-m(2) enclosures with ambient densities of tadpoles and natural river biota, bullfrog tadpoles caused a 48% reduction in survivorship of R. boylii, and a 24% decline in mass at metamorphosis. Bullfrog larvae had smaller impacts on Pacific treefrogs, Hyla regilla, causing 16% reduction in metamorph size, and no significant effect on survivorship. Bullfrog tadpoles significantly affected benthic algae, although effects varied across sites. Responses to bullfrogs in field settings were similar qualitatively to results seen in smaller-scale experiments designed to study size-structured competition among disparate age/size classes of species pairs and trios. Competition from large overwintering bullfrog larvae significantly decreased survivorship and growth of native tadpoles. Competition from recently hatched bullfrog larvae also decreased survivorship of R. boylii and H. regilla. Native species competed weakly, both interspecifically and intraspecifically. The only suggestion of a negative impact of a native species on bullfrogs was a weak effect of H. regilla on recent hatchlings. Competition appeared to be mediated by algal resources, and there was no evidence for behavioral or chemical interference. These results indicate that, through larval interactions, bullfrogs can exert differential effects on native frogs and perturb aquatic community structure.},
keywords = {algae, biological invasions, California, grazing, Hyla regilla, Rana boylii, Rana catesbeiana, rivers, size-structured competition},
pubstate = {published},
tppubtype = {article}
}
I studied the invasion of Rana catesbeiana (the bullfrog) into a northern California river system where bullfrogs are not native. Native yellow-legged frogs, Rana boylii, a species of special concern, were almost an order of magnitude less abundant in reaches where bullfrogs were well established. I assessed the potential role of larval competition in contributing to this displacement in a series of field manipulations of tadpole density and species composition. The impact of R. catesbeiana on native tadpoles in the natural community agreed with the outcome of more artificial experiments testing pairwise and three-way interactions. In 2-m(2) enclosures with ambient densities of tadpoles and natural river biota, bullfrog tadpoles caused a 48% reduction in survivorship of R. boylii, and a 24% decline in mass at metamorphosis. Bullfrog larvae had smaller impacts on Pacific treefrogs, Hyla regilla, causing 16% reduction in metamorph size, and no significant effect on survivorship. Bullfrog tadpoles significantly affected benthic algae, although effects varied across sites. Responses to bullfrogs in field settings were similar qualitatively to results seen in smaller-scale experiments designed to study size-structured competition among disparate age/size classes of species pairs and trios. Competition from large overwintering bullfrog larvae significantly decreased survivorship and growth of native tadpoles. Competition from recently hatched bullfrog larvae also decreased survivorship of R. boylii and H. regilla. Native species competed weakly, both interspecifically and intraspecifically. The only suggestion of a negative impact of a native species on bullfrogs was a weak effect of H. regilla on recent hatchlings. Competition appeared to be mediated by algal resources, and there was no evidence for behavioral or chemical interference. These results indicate that, through larval interactions, bullfrogs can exert differential effects on native frogs and perturb aquatic community structure.
1996
Power, Mary E.; Tilman, David; Estes, James A.; Menge, Bruce A.; Bond, L. Scott Mills William J.; Daily, Gretchen; Castilla, Juan Carlos; Lubchenco, Jane; Paine, Robert T.
Challenges in the quest for keystones Journal Article
In: BioScience, vol. 46, no. 8, pp. 609-620, 1996, ISSN: 0006-3568, (File size exceeds Angelo maximum; see the stable link attached.).
Links | BibTeX | Tags: biological invasions, fish community, interaction strength, Lake Michigan, mass mortality, pocket gophers, river food webs, rocky intertidal community, sea otter predation, species concept
@article{Power1996b,
title = {Challenges in the quest for keystones},
author = {Mary E. Power and David Tilman and James A. Estes and Bruce A. Menge and L. Scott Mills William J. Bond and Gretchen Daily and Juan Carlos Castilla and Jane Lubchenco and Robert T. Paine},
url = {http://www.jstor.org/stable/1312990},
doi = {10.2307/1312990},
issn = {0006-3568},
year = {1996},
date = {1996-09-00},
journal = {BioScience},
volume = {46},
number = {8},
pages = {609-620},
note = {File size exceeds Angelo maximum; see the stable link attached.},
keywords = {biological invasions, fish community, interaction strength, Lake Michigan, mass mortality, pocket gophers, river food webs, rocky intertidal community, sea otter predation, species concept},
pubstate = {published},
tppubtype = {article}
}