2006
Thomsen, M. A.; D’Antonio, C. M.; Suttle, K. B.; Sousa, W. P.
Ecological resistance, seed density and their interactions determine patterns of invasion in a California coastal grassland Journal Article
In: Ecology Letters, vol. 9, no. 2, pp. 160-170, 2006.
Abstract | Links | BibTeX | Tags: Climate, competition, exotic, invasibility, Mediterranean, propagule supply, wateravailability
@article{Thomsen2006,
title = {Ecological resistance, seed density and their interactions determine patterns of invasion in a California coastal grassland},
author = {M. A. Thomsen and C. M. D'Antonio and K. B. Suttle and W. P. Sousa},
url = {https://angelo.berkeley.edu/wp-content/uploads/sites/59/Thomsen_2006_EcoLetters.pdf},
doi = {10.1111/j.1461-0248.2005.00857.x},
year = {2006},
date = {2006-02-01},
journal = {Ecology Letters},
volume = {9},
number = {2},
pages = {160-170},
abstract = {Relatively little experimental evidence is available regarding how ecological resistance and propagule density interact in their effects on the establishment of invasive exotic species. We examined the independent and interactive effects of neighbour cover (biotic resistance), winter vs. spring water addition (abiotic resistance) and seed density on the invasion of the European perennial grass Holcus lanatus into a California coastal grassland dominated by exotic annual grasses. We found that decreased competition from resident exotic grasses had no effect. In contrast, increased late-season water availability eroded the abiotic resistance offered by naturally dry conditions, facilitating invasion. Finally, watering treatment and seed density interacted strongly in determining seedling survival: while seedling mortality was close to 100% in ambient and winter water addition plots, survivor numbers increased with seed density in spring-watered plots. Thus, decreased abiotic resistance can amplify the effect of increased propagule density on seedling establishment, thereby increasing the likelihood of invasion.},
keywords = {Climate, competition, exotic, invasibility, Mediterranean, propagule supply, wateravailability},
pubstate = {published},
tppubtype = {article}
}
Relatively little experimental evidence is available regarding how ecological resistance and propagule density interact in their effects on the establishment of invasive exotic species. We examined the independent and interactive effects of neighbour cover (biotic resistance), winter vs. spring water addition (abiotic resistance) and seed density on the invasion of the European perennial grass Holcus lanatus into a California coastal grassland dominated by exotic annual grasses. We found that decreased competition from resident exotic grasses had no effect. In contrast, increased late-season water availability eroded the abiotic resistance offered by naturally dry conditions, facilitating invasion. Finally, watering treatment and seed density interacted strongly in determining seedling survival: while seedling mortality was close to 100% in ambient and winter water addition plots, survivor numbers increased with seed density in spring-watered plots. Thus, decreased abiotic resistance can amplify the effect of increased propagule density on seedling establishment, thereby increasing the likelihood of invasion.
2000
Levine, Jonathan M.
Species diversity and biological invasions: relating local process to community pattern Journal Article
In: Science, vol. 288, no. 5467, pp. 852-854, 2000, ISSN: 0036-8075.
Abstract | Links | BibTeX | Tags: biodiversity, ecosystem, grasslands, invasibility, resistance, stability
@article{Levine2000b,
title = {Species diversity and biological invasions: relating local process to community pattern},
author = {Jonathan M. Levine},
url = {https://angelo.berkeley.edu/wp-content/uploads/sites/59/Science-2000-Levine-852-4.pdf},
issn = {0036-8075},
year = {2000},
date = {2000-05-05},
journal = {Science},
volume = {288},
number = {5467},
pages = {852-854},
abstract = {In a California riparian system, the most diverse natural assemblages are the most invaded by exotic plants. A direct in situ manipulation of local diversity and a seed addition experiment showed that these patterns emerge despite the intrinsic negative effects of diversity on invasions. The results suggest that species loss at small scales may reduce invasion resistance. At community-wide scales, the overwhelming effects of ecological factors spatially covarying with diversity, such as propagule supply, make the most diverse communities most likely to be invaded.},
keywords = {biodiversity, ecosystem, grasslands, invasibility, resistance, stability},
pubstate = {published},
tppubtype = {article}
}
In a California riparian system, the most diverse natural assemblages are the most invaded by exotic plants. A direct in situ manipulation of local diversity and a seed addition experiment showed that these patterns emerge despite the intrinsic negative effects of diversity on invasions. The results suggest that species loss at small scales may reduce invasion resistance. At community-wide scales, the overwhelming effects of ecological factors spatially covarying with diversity, such as propagule supply, make the most diverse communities most likely to be invaded.