2001
Levine, Jonathan M.
Local interactions, dispersal, and native and exotic plant diversity along a California stream Journal Article
In: Oikos, vol. 95, no. 3, pp. 397-408, 2001, ISSN: 0030-1299.
Abstract | Links | BibTeX | Tags: biodiversity, community invasibility, ecosystem, invasion resistance, mimulus-guttatus, patterns, populations, regional processes, seed dispersal, species richness
@article{Levine2001,
title = {Local interactions, dispersal, and native and exotic plant diversity along a California stream},
author = {Jonathan M. Levine},
url = {https://angelo.berkeley.edu/wp-content/uploads/sites/59/Local-Interactions-Dispersal-and-Native-and-Exotic-Plant-Diversity-along-a-California-Stream_Levine_2001.pdf},
doi = {10.1034/j.1600-0706.2001.950304.x},
issn = {0030-1299},
year = {2001},
date = {2001-12-00},
journal = {Oikos},
volume = {95},
number = {3},
pages = {397-408},
abstract = {Although the species pool, dispersal, and local interactions all influence species diversity, their relative importance is debated. I examined their importance in controlling the number of native and exotic plant species occupying tussocks formed by the sedge Carex nudata along a California stream. Of particular interest were the factors underlying a downstream increase in plant diversity and biological invasions. I conducted seed addition experiments and manipulated local diversity and cover to evaluate the degree to which tussocks saturate with species, and to examine the roles of local competitive processes, abiotic factors, and seed supply in controlling the system-wide patterns.
Seeds of three native and three exotic plants sown onto experimentally assembled tussock communities less successfully established on tussocks with a greater richness of resident plants. Nonetheless, even the most diverse tussocks were somewhat colonized, suggesting that tussocks are not completely saturated with species. Similarly, in an experiment where I sowed seeds onto natural tussocks along the river, colonization increased two- to three-fold when I removed the resident species. Even on intact tussocks, however, seed addition increased diversity, indicating that the tussock assemblages are seed limited. Colonization success on cleared and uncleared tussocks increased downstream from km 0 to km 3 of the study site, but showed no trends from km 3 to km 8. This suggests that while abiotic and biotic features of the tussocks may control the increase in diversity and invasions from km 0 to km 3, similar increases from km 3 to km 8 are more likely explained by potential downstream increases in seed supply. The effective water dispersal of seed mimics and prevailingly downstream winds indicated that dispersal most likely occurs in a downstream direction. These results suggest that resident species diversity, competitive interactions, and seed supply similarly influence the colonization of native and exotic species.},
keywords = {biodiversity, community invasibility, ecosystem, invasion resistance, mimulus-guttatus, patterns, populations, regional processes, seed dispersal, species richness},
pubstate = {published},
tppubtype = {article}
}
Although the species pool, dispersal, and local interactions all influence species diversity, their relative importance is debated. I examined their importance in controlling the number of native and exotic plant species occupying tussocks formed by the sedge Carex nudata along a California stream. Of particular interest were the factors underlying a downstream increase in plant diversity and biological invasions. I conducted seed addition experiments and manipulated local diversity and cover to evaluate the degree to which tussocks saturate with species, and to examine the roles of local competitive processes, abiotic factors, and seed supply in controlling the system-wide patterns.
Seeds of three native and three exotic plants sown onto experimentally assembled tussock communities less successfully established on tussocks with a greater richness of resident plants. Nonetheless, even the most diverse tussocks were somewhat colonized, suggesting that tussocks are not completely saturated with species. Similarly, in an experiment where I sowed seeds onto natural tussocks along the river, colonization increased two- to three-fold when I removed the resident species. Even on intact tussocks, however, seed addition increased diversity, indicating that the tussock assemblages are seed limited. Colonization success on cleared and uncleared tussocks increased downstream from km 0 to km 3 of the study site, but showed no trends from km 3 to km 8. This suggests that while abiotic and biotic features of the tussocks may control the increase in diversity and invasions from km 0 to km 3, similar increases from km 3 to km 8 are more likely explained by potential downstream increases in seed supply. The effective water dispersal of seed mimics and prevailingly downstream winds indicated that dispersal most likely occurs in a downstream direction. These results suggest that resident species diversity, competitive interactions, and seed supply similarly influence the colonization of native and exotic species.
Seeds of three native and three exotic plants sown onto experimentally assembled tussock communities less successfully established on tussocks with a greater richness of resident plants. Nonetheless, even the most diverse tussocks were somewhat colonized, suggesting that tussocks are not completely saturated with species. Similarly, in an experiment where I sowed seeds onto natural tussocks along the river, colonization increased two- to three-fold when I removed the resident species. Even on intact tussocks, however, seed addition increased diversity, indicating that the tussock assemblages are seed limited. Colonization success on cleared and uncleared tussocks increased downstream from km 0 to km 3 of the study site, but showed no trends from km 3 to km 8. This suggests that while abiotic and biotic features of the tussocks may control the increase in diversity and invasions from km 0 to km 3, similar increases from km 3 to km 8 are more likely explained by potential downstream increases in seed supply. The effective water dispersal of seed mimics and prevailingly downstream winds indicated that dispersal most likely occurs in a downstream direction. These results suggest that resident species diversity, competitive interactions, and seed supply similarly influence the colonization of native and exotic species.
1998
Kupferberg, Sarah J.
Predator mediated patch use by tadpoles (Hyla regilla): Risk balancing or consequence of motionlessness? Journal Article
In: Journal of Herpetology, vol. 32, no. 1, pp. 84-92, 1998, ISBN: 0022-1511.
Abstract | Links | BibTeX | Tags: avoidance, behavior, differential predation, garter snakes, habitat use, larval anurans, locomotion, melanogaster, populations, stream-dwelling isopod, thamnophis
@article{Kupferberg1998,
title = {Predator mediated patch use by tadpoles (Hyla regilla): Risk balancing or consequence of motionlessness?},
author = {Sarah J. Kupferberg},
url = {https://angelo.berkeley.edu/wp-content/uploads/sites/59/Kupferberg_Herpetology1998.pdf},
isbn = {0022-1511},
year = {1998},
date = {1998-03-00},
journal = {Journal of Herpetology},
volume = {32},
number = {1},
pages = {84-92},
abstract = {To quantify the impact of garter snakes (Thamnophis hydrophilus, formerly T. couchii) on tadpole prey (Hyla regilla), I experimentally examined whether: (1) garter snakes have greater impact on tadpole numbers or on behavior; (2) tadpole patch choice follows the rule of minimizing the ratio of mortality risk, μ, to foraging gain, g; and (3) predator-induced resource avoidance influences algal production. In replicated enclosed pools constructed on gravel bars of a northern California river, garter snakes did not significantly reduce the number of tadpoles but did alter patch choice. Tadpoles spent less time in high food quality algae mats (Cladophora glomerata with epiphytic diatoms) and more time in low food quality patches (Zygnematales algae mats and sediments) when garter snakes were present than when they were absent. In mortality risk experiments, however, there were no significant differences in the numbers of tadpoles consumed among patch types, and garter snakes were not size selective. Therefore, patch choice did not follow the rule of minimizing μ/g. The change in patch choice was likely a consequence of the sublethal effect of garter snakes in which tadpole activity is decreased. For negatively buoyant tadpoles, decreased activity results in sinking away from floating algal resources. This apparent resource avoidance by tadpoles did not affect algal mass over the relatively short duration of the experiments.},
keywords = {avoidance, behavior, differential predation, garter snakes, habitat use, larval anurans, locomotion, melanogaster, populations, stream-dwelling isopod, thamnophis},
pubstate = {published},
tppubtype = {article}
}
To quantify the impact of garter snakes (Thamnophis hydrophilus, formerly T. couchii) on tadpole prey (Hyla regilla), I experimentally examined whether: (1) garter snakes have greater impact on tadpole numbers or on behavior; (2) tadpole patch choice follows the rule of minimizing the ratio of mortality risk, μ, to foraging gain, g; and (3) predator-induced resource avoidance influences algal production. In replicated enclosed pools constructed on gravel bars of a northern California river, garter snakes did not significantly reduce the number of tadpoles but did alter patch choice. Tadpoles spent less time in high food quality algae mats (Cladophora glomerata with epiphytic diatoms) and more time in low food quality patches (Zygnematales algae mats and sediments) when garter snakes were present than when they were absent. In mortality risk experiments, however, there were no significant differences in the numbers of tadpoles consumed among patch types, and garter snakes were not size selective. Therefore, patch choice did not follow the rule of minimizing μ/g. The change in patch choice was likely a consequence of the sublethal effect of garter snakes in which tadpole activity is decreased. For negatively buoyant tadpoles, decreased activity results in sinking away from floating algal resources. This apparent resource avoidance by tadpoles did not affect algal mass over the relatively short duration of the experiments.
1975
Phillips, M
A Study of the Population and Parasites of Blacktail (Odocoileus hemionus columbianus) on the NCCRP Journal Article
In: 1975.
BibTeX | Tags: Angelo Coast Range Reserve, parasitism, populations
@article{Phillips1975,
title = {A Study of the Population and Parasites of Blacktail (Odocoileus hemionus columbianus) on the NCCRP},
author = {M Phillips},
year = {1975},
date = {1975-01-01},
urldate = {1975-01-01},
keywords = {Angelo Coast Range Reserve, parasitism, populations},
pubstate = {published},
tppubtype = {article}
}