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Open Access Publications from the University of California

UCB Moorea Class: Biology and Geomorphology of Tropical Islands is an intensive field course (13 units), taught every Fall semester by UC Berkeley. A highly selective group of 20-22 undergraduate students spend a month on campus in Berkeley for lectures and labs five days a week, then go to the Richard Gump Biological Station on the island of Moorea in French Polynesia for nine weeks to carry out an intensive research project and to do some general educational field trips and labs, supervised by a number of professors and graduate student instructors. They learn all the stages of scientific research from conception of a project to giving talks and and writing. These papers are the result of their research.

Cover page of Pollination biology and reproductive ecology of  Scaevola taccada (Goodeniaceae) on Mo'orea, French Polynesia

Pollination biology and reproductive ecology of Scaevola taccada (Goodeniaceae) on Mo'orea, French Polynesia

(2008)

Plants often depend on other organisms to pollinate their flowers in order to successfully reproduce. On an island, plants face multiple challenges to establish and persist, especially if the plant depends solely on a specific pollinator not present on the island. A pollination and reproduction study was conducted on Scaevola taccada, a widespread coastal shrub, on the island of Mo’orea in French Polynesia. The pollinator community of S. taccada was composed of eight insect species, with the recently introduced honeybee, Apis mellifera, being the most frequent floral visitor. Both site and wind speed were found to have significant effects on visitation rate. A high percentage of successful seed set from pollinator-exclusion studies suggested S. taccada may be able to successfully self-pollinate. The length of flowering times was found to be significantly associated with successful seed set, with flowering times serving as an indicator for successful pollination events. With the ability to outcross and to self-reproduce, S. taccada has adapted to persist on a changing island environment.

Cover page of A survey of mushroom corals and the effects of water flow on sediment removal in Fungia species

A survey of mushroom corals and the effects of water flow on sediment removal in Fungia species

(2008)

Free living corals are and important part of coral reef ecosystems. The members of the coral genus Fungia (Scleractinia, Fungiidae) exist as individual, free living, polyps. Fungiid corals can move actively, though expiation of body tissue, or passively, via being carried by strong currents. It was observed that fungiids were often found in close proximity to one another in the shallow reefs of Moorea, French Polynesia. This study set out to determine if fungiids were aggregated and if so, to test three factors which may be contributing to these aggregations; fungiid size, substrate preference and current speed. Furthermore, the effect of current on the rate at which fungiids can remove sediment from their bodies was tested. It was found that fungiids are aggregated. These aggregations consist of individuals of similar ages. Aggregations are found in branching corals much more often than expected and on sand much less often than expected. Aggregated fungiids are found in areas of lower current speed than solitary fungiids. Finally, high current speeds increase fungiids ability to remove sediment from their bodies.

Cover page of Community Structure, Ciculation and Seawater pH in a Coral Reef Ecosystem (Moorea, French Polynesia)

Community Structure, Ciculation and Seawater pH in a Coral Reef Ecosystem (Moorea, French Polynesia)

(2008)

Seawater pH measurements across different reef settings in Cook’s Bay (Moorea, French Polynesia) taken during October and November 2008 were compared and related to circulation and community composition in the reef flat, fringing reef, lagoon and bay. pH is thus an easy measure of seawater carbonate chemistry, which can be altered by community metabolism. Current velocity and percent cover of coral were greatest across the reef flat, yet no significant difference in seawater pH was found between the algal ridge and the lagoon. However, pH variations were discernible between the surface water from the fringing reef, which had the highest percent cover of algae, and water sampled at depth in the lagoon and bay. This study thus brings a better understanding of pH differences within a reef ecosystem and can serve as a benchmark for monitoring ocean acidification.

Cover page of Corridors and plant invasions: A comparative study of the role of roadsides and hiking trails on plant invasions in Moorea, French Polynesia

Corridors and plant invasions: A comparative study of the role of roadsides and hiking trails on plant invasions in Moorea, French Polynesia

(2008)

Islands have been shown to be highly vulnerable to the invasion of non-native plant species. The island of Moorea, French Polynesia, is both geographically isolated and lacks a high diversity of native plant species, factors that promote the invasion of non-native plants. Disturbed areas, such as roadsides, have also been closely associated with the colonization and spread of non-native and invasive plants. Roads are particularly important vectors of alien plant invasions, aiding in dispersal and likely serving as starting points for edge effects. The present study considers both the alien and native flora in tropical secondary forests adjacent to paved vehicle roads, dirt vehicle roads, and backcountry hiking trails on Moorea, French Polynesia. The composition of total and alien plant species, level of invasion, and significance of edge effects were analyzed between the three corridor types. Significant differences in the alien plant compositions and level of invasion were found between the corridor types. Dirt roads were found to be the most invaded, followed by paved roads and then hiking trails. Two plant species, W. trilobata and A. falcatoria, showed dramatic edge effects into the adjacent forest; however, only the spread of W. trilobata was significantly affected by corridor type, with paved roads showing the greatest effect.

Cover page of A PRELIMINARY SURVEY OF APOIDEA (ANTHOPHILA) AND THEIR USE OF FLORAL RESOURCES ON THE ISLAND OF MO'OREA, FRENCH POLYNESIA

A PRELIMINARY SURVEY OF APOIDEA (ANTHOPHILA) AND THEIR USE OF FLORAL RESOURCES ON THE ISLAND OF MO'OREA, FRENCH POLYNESIA

(2008)

The terrestrial biota of the French Polynesian archipelago presents a unique opportunity for study due to a relatively poor understanding of its biology. Among the terrestrial invertebrates, the Apoidea are one of many taxa with incompletely documented biodiversity. This study investigated the diversity of the bees on the island of Mo'orea, part of the Society Islands in French Polynesia. Across a range of elevations, I collected 239 individual bees and observed the floral visits of an additional 266 bees. The visited floral species were recorded to assess apoid use of floral resources, and vegetation surveys of collection sites were conducted to assess the available floral community. A total of five genera of bees were found on Mo'orea, including two which are recorded for the first time in the Society Islands. This study suggests that introduced species, rather than native species, comprise the bee biota of Mo'orea, with the longest established species seemingly introduced at or around the time of colonization by early Polynesians. With the exception of the genera Lithurgus and Megachile, bee genera were found to rely predominantly on non-native floral resources. Floral visitation predilection by Mo'orean bees may prove to further the spread of introduced and invasive floral species.

Cover page of Spider Diversity Patterns on the Island of Moorea

Spider Diversity Patterns on the Island of Moorea

(2008)

The island of Moorea, Society Islands (French Polynesia) provides a unique opportunity to examine patterns of spider diversity on a small high volcanic island. I collected spiders at a range of elevations (0~900m) and habitats (disturbed coastal, streamside, mid-elevation ridges and high mountains). This allowed me to map distributions and look at differences in spider assemblages. Specimens were identified to family level. I found a total of 30 different morphospecies. A total of 1738 spiders were collected (using sweep netting and active searching) represented by 12 families, 16 determined genera and 12 determined species. My survey revealed that streamside and coastal communities had the greatest overall biodiversity while having the lowest native diversity. Mid-elevation ridges and high mountains had lower overall diversity but higher native biodiversity. Differences in overall diversity may be due to variation in structural differences between these habitats. In the future, more extensive surveys of the spider fauna need to be done to determine whether structural diversity, elevation or vegetation type is most responsible for different distributions of biodiversity. The spider fauna of Moorea is dominated by nonnative species. As anthropomorphic disturbances on the environment increase, more efforts should be directed towards conservation of mid-elevation ridge and high mountain sites which possess more native species.

Cover page of Feeding preferences of the Cushion Star Culcita novaeguineae in the presence of the Crown of Thorns Starfish Acanthaster planci

Feeding preferences of the Cushion Star Culcita novaeguineae in the presence of the Crown of Thorns Starfish Acanthaster planci

(2008)

Crown of thorns starfish (Acanthaster planci Linné 1758) are notorious coral reef devastators; they decimate coral populations, thus changing the coral reef habitat and killing many organisms that depend on the coral. Culcita novaeguineae (Muller and Troschel 1842), or cushion stars, are corallivores and generalists that live in Pacific reefs. Because C. novaeguineae and A. planci have similar food preferences, the presence of crown of thorns may change cushion stars’ eating habits. This study explored cushion star ecology and their laboratory feeding preferences in the presence and absence of crown of thorns. Laboratory experiments were conducted with three coral food choices (Porites sp., Acropora sp., and Monopora sp.) and algae covered rock. Cushion stars only ate Acropora sp. and Monopora sp. in laboratory experiments. They found among all three of those coral genera in the field and were rarely found near Pocillopora sp. Crown of thorns presence had no significant impact on the food choice in the lab or substrate choice of cushion stars in the field. General laboratory trends indicate cushion stars ate more frequently and preferred rock as substrate in the presence of crown of thorns.

Cover page of Varying impact of human feeding on Pink Whiprays, Himantura fai, at two sites on Mo'orea

Varying impact of human feeding on Pink Whiprays, Himantura fai, at two sites on Mo'orea

(2008)

This study was conducted on Mo'orea, French Polynesia to investigate and record the impacts of ecotourism on two populations of himantura fai, pink whiprays or pink whiptail stingrays. Two sites were chosen each with varying impact to rays. Photographs and recordings were made and analyzed. Thirty eight individual rays were identified, 29 from one site and 8 from the other. Five kinds of scarring were described and compared between the two. It was found the more dense ray population was more injured and impacted and habituated to humans. The higher frequency of injury suggests a lower quality of life and indeed a negative impact from ecotourism. A mock mark and recapture study was done using the Lincoln-Peterson method. The population estimates were 30 and 8, suggesting the 29 and 9 rays identified are the entire populations. No rays were seed at both sites, which suggests site fidelity.

Cover page of The Correlation Between Herbivory and Medicinal Activity in Thespesia Populnea, Hibiscus Tiliaceus, and Hibiscus Rosa-Sinensis on Mo'orea, French Polynesia

The Correlation Between Herbivory and Medicinal Activity in Thespesia Populnea, Hibiscus Tiliaceus, and Hibiscus Rosa-Sinensis on Mo'orea, French Polynesia

(2008)

While secondary compounds are produced by plants in low abundance, these bioactive compounds are essential to human survival for their medicinal applications. These same compounds are crucial to plants, having evolved as defense mechanisms against herbivory. Chief among the theories of plant responses to herbivory, the Optimal Defense Theory (ODT) hypothesizes that plants will allocate defenses in direct proportion to the risk of a particular plant part to herbivory and the value of that part in terms of loss of fitness to the entire plant. Through insect damage assessments and antimicrobial assays, this study investigates the correlation between herbivory and medicinal activity and whether or not the within-plant ODT is followed in three ethnobotanically useful Malvaceae species, Thespesia populnea, Hibiscus tiliaceus and Hibiscus rosa-sinensis. All three plant species demonstrated an inverse relationship between herbivory and medicinal activity. Variation in secondary composition data from both insect damage assessment and antimicrobial tests supported the ODT.

Cover page of The Effects of Lunar Cycling and Fish Predation on Decapod Larval Abundances

The Effects of Lunar Cycling and Fish Predation on Decapod Larval Abundances

(2008)

Planktonic larvae of many marine organisms have been known to cycle in abundance according to lunar phases. It is unknown, however, if these cycles are caused by timed release of larvae by the adults in accordance with lunar cues or if predation pressure on the larvae varies across the lunar cycle. Larvae of some invertebrate taxa are capable of predator detection and avoidance, suggesting that predation on meroplankton is lower than dispersal models predict. This study tracked lunar cycling of decapod larvae from Oct. 6, 2008 to Nov. 13, 2008 in Moorea, French Polynesia. Predator avoidance capabilities of the larvae and relative predation pressure during each phase of the moon were also tested in a laboratory setting. Larval abundances on the reef were highest during the new moon period and lowest during quarter and full moons, suggesting predation does affect lunar abundance cycling. Decapod megalops stage larvae were found to be capable of predator avoidance but younger stage zoeas were not. Predation pressure was also found to correlate directly with light intensity. Results of this study suggest predation does affects larval population cycling, however it is possible that both predation and larval release timing play a role in shaping larval abundances and dispersal.