Pacific Science, Volume 65, Numbers 1-4, 2011

Reptiles of Fais Island, Yap State, Federated States of Micronesia.

Buden, Donald W. — Fri, 01 Apr 2011 00:00:00 GMT

Eleven species of reptiles (six skinks, four geckos, one monitor lizard) are recorded from Fais Island, Micronesia, four of them (Gehyra mutilata, Lepidodactylus moestus, L. sp., and Eugongylus albofasciolatus) for the first time. The skinks Emoia caeruleocauda and E. jakati are the most common species; G. mutilate is the most common gecko in edificarian habitats, and L. moestus is the most common outside the areas of human habitation. Nearly all of the species are widespread in the western Pacific region, although Eutropis sp. is at the easternmost limits of its distribution in the Caroline Islands on Fais. The monitor lizard Varanus indicus was introduced during the Japanese administration. The other species may have arrived by natural dispersal, or by human assistance, or a combination of the two. v. ill. 23 cm.; Quarterly

Acanthurus nigros Gunther, a Valid Species of Surgeonfish, Distinct from the Hawaiian A. nigroris Valenciennes.

Randall, John E.; DiBattista, Joseph D.; Wilcox, Christie — Fri, 01 Apr 2011 00:00:00 GMT

The Blueline Surgeonfish, Acanthurus nigroris Valenciennes, formerly considered as wide-ranging in the central and western Pacific, is restricted to the Hawaiian Islands. Acanthurus nigros Gü nther, type locality Vanuatu, is available for the sister species from the Pitcairn Islands west to the Great Barrier Reef and Caroline Islands. Although these two species are very similar in color, there are fin-ray and gill-raker differences, and the genetic difference (i.e., 4.12% mtDNA cytochrome b sequence divergence) alone warrants species recognition. v. ill. 23 cm.; Quarterly

Newly Collected Specimens of the Sleeper Eleotris acanthopoma (Teleostei: Eleotridae) from French Polynesia Indicate a Wide and Panmictic Distribution in the West and South Pacific.

Maeda, Ken; Mukai, Takahiko; Tachihara, Katsunori — Fri, 01 Apr 2011 00:00:00 GMT

The morphology of Eleotris acanthopoma collected from Moorea in French Polynesia is described. This is the first record of this species from French Polynesia, greatly expanding the known range, which was previously only considered to extend from southern Japan to New Caledonia. Nucleotide sequences of the mitochondrial ND5 gene of several Eleotris species and related genera indicate that E. acanthopoma from Moorea belongs to the same lineage as E. acanthopoma from Japan and the Philippines. Despite being separated by a distance of approximately 10,000 km, two of the specimens from Moorea and one from the Philippines had identical nucleotide sequences. Results of this study indicate that extensive dispersal occurs during the pelagic larval stage of this species. v. ill. 23 cm.; Quarterly

New Records of Commercially Valuable Black Corals (Cnidaria: Antipatharia) from the Northwestern Hawaiian Islands at Mesophotic Depths.

Fri, 01 Apr 2011 00:00:00 GMT

Mesophotic coral reef ecosystems are notoriously undersurveyed worldwide and particularly in remote locations like the Northwestern Hawaiian Islands ( NWHI). A total of 37 mixed-gas technical dives were performed to depths of 80 m across the NWHI to survey for the presence of the invasive octocoral Carijoa sp., the invasive red alga Acanthophora spicifera, and conspicuous megabenthic fauna such as black corals. The two invasive species were not recorded from any of the surveys, but two commercially valuable black coral species, Antipathes griggi and Myriopathes ulex, were found, representing substantial range expansions for these species. Antipathes griggi was recorded from the islands of Necker and Laysan in 58 – 70 m, and Myriopathes ulex was recorded from Necker Island and Pearl and Hermes Atoll in 58 – 70 m. Despite over 30 yr of research in the NWHI, these black coral species had remained undetected. The new records of these conspicuous marine species highlight the utility of deepdiving technologies in surveying the largest part of the depth range of coral reef ecosystems (40 – 150 m), which remains largely unexplored. v. ill. 23 cm.; Quarterly

Community Composition of Elasmobranch Fishes Utilizing Intertidal Sand Flats in Moreton Bay, Queensland, Australia.

Pierce, Simon J.; Scott-Holland, Tracey B.; Bennett, Michael B. — Fri, 01 Apr 2011 00:00:00 GMT

Thirteen elasmobranch species were collected during a 4-yr survey of the intertidal margins of Moreton Bay, a large subtropical embayment in southeastern Queensland, Australia. Stingrays were the most common large predators in the intertidal zone, with total catch dominated numerically by blue-spotted maskray, Neotrygon kuhlii (53.8%); estuary stingray, Dasyatis fluviorum (22.2%); and brown whipray, Himantura toshi (10.2%). There was a significant female bias within intertidal populations of N. kuhlii and D. fluviorum. Courtship behaviors were observed in July and September in D. fluviorum and in January for whitespotted eagle ray, Aetobatus narinari. Dasyatis fluviorum, a threatened Australian endemic stingray, remains locally abundant within the bay. Overall, the inshore elasmobranch fauna of Moreton Bay is relatively species rich compared with similar studies elsewhere in Australia, emphasizing the regional importance of this ecosystem. v. ill. 23 cm.; Quarterly

Chemical Ecology of Red Mangroves, Rhizophora mangle, in the Hawaiian Islands.

Fry, Brian; Cormier, Nicole — Fri, 01 Apr 2011 00:00:00 GMT

The coastal red mangrove, Rhizophora mangle L., was introduced to the Hawaiian Islands from Florida 100 yr ago and has spread to cover many shallow intertidal shorelines that once were unvegetated mudflats. We used a field survey approach to test whether mangroves at the land-ocean interface could indicate watershed inputs, especially whether measurements of leaf chemistry could identify coasts with high nutrient inputs and high mangrove productivities. During 2001 – 2002, we sampled mangroves on dry leeward coasts of southern Moloka‘i and O‘ahu for 14 leaf variables including stable carbon and nitrogen isotopes (δ 13C, δ 15N), macronutrients (C, N, P), trace elements (B, Mn, Fe, Cu, Zn), and cations ( Na, Mg, K, Ca). A new modeling approach using leaf Na, N, P, and δ 13C indicated two times higher productivity for mangroves in urban versus rural settings, with rural mangroves more limited by low N and P nutrients and high-nutrient urban mangroves more limited by freshwater inputs and salt stress. Leaf chemistry also helped identify other aspects of mangrove dynamics: especially leaf d 15N values helped identify groundwater N inputs, and a combination of strongly correlated variables (C, N, P, B, Cu, Mg, K, Ca) tracked the mangrove growth response to nutrient loading. Overall, the chemical marker approach is an efficient way to survey watershed forcing of mangrove forest dynamics. v. ill. 23 cm.; Quarterly

Stream Nutrient Concentrations on the Windward Coast of Hawai‘I Island and Their Relationship to Watershed Characteristics.

Michaud, Jene; Wiegner, Tracy — Fri, 01 Apr 2011 00:00:00 GMT

Dissolved inorganic and organic nutrients and physiochemical parameters were measured in 24 Hawai‘i Island streams. Particulate nutrients and instantaneous nutrient and sediment fluxes were measured in half of these streams. Stream waters were dilute and slightly alkaline and had low concentrations of ammonium, orthophosphate, dissolved organic phosphorus, and total suspended solids. Particulate matter comprised 45%, 73%, and 28% of nitrogen, phosphorus, and carbon pools, respectively. Dissolved nitrogen was comprised primarily of organic nitrogen (54%) and nitrate (34%). In some streams, nitrate and total nitrogen concentrations were slightly elevated relative to Hawai‘i Department of Health (HDOH) water quality standards. Instantaneous nitrate yields for the streams plus 26 HDOH stations were calculated, and the average from the combined data set was 7.1 (SD 11.1) moles N day-1 km-2. Nitrate concentrations and yields were 2.1 and 3.5 times higher, respectively, in Kohala watersheds than in Mauna Kea watersheds. Regression analysis was used to evaluate whether water quality parameters are predicted by watershed area, mean annual rainfall, population density, or percentage of agricultural land. Many water quality parameters were not predicted by these variables. In Mauna Kea streams, concentrations of dissolved organic nitrogen and dissolved organic carbon increased with increasing watershed area, nitrate concentrations increased with increasing population density, and both specific conductivity and nitrate yield increased with increasing percentage of agricultural lands. In Kohala streams, nitrate concentrations and yields were not predicted by watershed characteristics. Overall, watershed characteristics, as quantified in this study, were not strong predictors of water quality. v. ill. 23 cm.; Quarterly

Sediment Transport, and Effects of Feral Pig (Sus scrofa) Exclusion in a Forested Hawaiian Watershed.

Fri, 01 Apr 2011 00:00:00 GMT

Browsing and trampling by nonnative feral pigs (Sus scrofa) negatively impact native flora and fauna in forested ecosystems and cause soil compaction. However, their impact on runoff and erosion is largely unknown. This study addressed this knowledge gap by investigating effects of feral pigs on runoff volume and total suspended solids (TSS) in runoff from the upper forested area of a Hawaiian watershed. Correlations between TSS, runoff, and other environmental variables were also examined. Runoff was collected monthly after 11 individual storm events from June 2008 to April 2009 at seven sites in the Mänoa watershed on the island of O‘ahu. Each site consisted of paired runoff plots (5.04 m2) with one plot located inside a fenced pig exclosure (exclosures 1 yr old at study initiation) and the other located in an adjacent area open to feral pigs. Forest composition and structure (stem density, stand basal area, and seedling/ sapling counts) were quantified at each site. Soil moisture, throughfall, runoff volume, and TSS in runoff were sampled for each storm event. The seven sites varied considerably in terms of forest structure, with stem densities ranging from 1,500 to 9,000 stems ha-1 and basal areas ranging from 20 to 132 m2 ha-1. Vegetation at all sites was dominated by nonnative species. Runoff volumes from fenced and unfenced plots were highly variable, ranging from <1 to >128 liters. TSS levels in runoff ranged from <0.01 to 7.05 g liter-1. TSS levels were generally higher in wet-season months, but this pattern was not consistent across all sites. TSS in runoff was significantly correlated with throughfall, soil moisture, and coarse woody debris cover. Although pig exclusion did not reduce TSS, significant reductions in runoff volume from pig exclusion plots were observed at one site, and two other sites showed a similar trend. Longer-term studies may reveal stronger or more consistent impacts of feral pigs. Using paired fenced versus unfenced runoff plots to study erosion impacts of feral pigs is a novel approach, and results from this study will help forest managers better understand and manage runoff and erosion dynamics. v. ill. 23 cm.; Quarterly

Primary Succession along an Elevation Gradient 15 Years after the Eruption of Mount Pinatubo, Luzon, Philippines.

Marler, Thomas E.; del Moral, Roger — Fri, 01 Apr 2011 00:00:00 GMT

We determined vegetation structure and environmental variables in the Pasig-Potrero and Sacobia River systems on the east flank of Mount Pinatubo, Luzon, Philippines, to define growth form and taxonomic groups that have influenced primary succession during the 15 yr since the eruption. We selected eight sites within an east-west range of 11.5 km, a north-south range of 7 km, and an elevation gradient of ca. 500 m. The 58 plant taxa we encountered among 63 sampled plots belonged to 21 families. Cover was dominated by Parasponia rugosa (tree) and Saccharum spontaneum (large grass). Cover of these two species was inversely related at the plot level. Exotic species represented nearly 60% of this flora but only 32% of the vegetation cover. Family richness was high for Asteraceae, Fabaceae, and Poaceae. Elevation, distance to the caldera, and distance to human settlement exhibited the most control over the vegetation. The influence of elevation on cover, species composition, and structure differed in these adjacent canyons. Plot species richness, cover, and diversity indices were greatest at the highest elevation of the Pasig-Potrero River. On a small scale, current dominant species may control progression of species assemblages as mediated by geophysical, chemical, facilitative, and competitive changes. Our findings indicate that ongoing anthropogenic disturbances and the prevalence of exotic species may prevent the vegetation from returning to its preeruption state. The invasive Pennisetum setaceum and Chromolaena odorata were widespread in this landscape, and their negative influence on vegetation recovery is probable. Ours is the first detailed survey of vegetation on newly created volcanic surfaces in the region and provides a baseline for understanding the landscape-level processes determining continuing succession. v. ill. 23 cm.; Quarterly

Plant Dispersal, Introduced Species, and Vegetation Change in the South Pacific Kingdom of Tonga.

Fall, Patricia L.; Drezner,Taly Dawn — Fri, 01 Apr 2011 00:00:00 GMT

Dispersal guilds hold key ecological implications for the vegetation history of islands. This study considers dispersal vectors in conjunction with species origin and growth form to characterize vegetation dynamics on the islands of Tonga in the South Pacific. Data for over 700 species compiled from published literature on the plants of Tonga support a comparative study of dispersal mechanisms and growth forms for native flora, species brought by Polynesian settlers, and taxa introduced since European contact. The indigenous flora, predominantly trees, is characterized primarily by endozoochorous (internal) dispersal through birds and bats. European introductions, primarily herbs, disperse commonly through epizoochorous (external) animal dispersal. Bat dispersal is most important for overstory indigenous and Polynesian trees and vines. In addition, rodents commonly eat seeds of native rain forest trees. The understory, which is overwhelmingly introduced, consists of wind-dispersed and externally animal-dispersed species, which are often early successional. Rain forest thinning encourages establishment of wind-dispersed species and nonnatives. Thus, the prospect of sustained native flora in Tonga would be enhanced by the preservation of bats, a particularly important dispersal vector for indigenous and endemic species, and by the eradication of introduced rats. v. ill. 23 cm.; Quarterly

Floristic Composition and Natural History Characteristics of Dry Forests in the Pacific.

Fri, 01 Apr 2011 00:00:00 GMT

We compare the floristic composition of tropical dry forests at the stand level using Gentry’s transect method (0.1 ha) in some of the largest and highest-quality remaining fragments in the Pacific (Hawai‘i, 15 sites; Fiji, 9; the Marianas, 3; the Marquesas, 6; New Caledonia, 7) and compare results with neotropical dry forests. A total of 299 species or morphospecies ≥2.5 cm diameter at breast height were identified from all 40 sites in the Pacific. Rubiaceae (28 spp.), Euphorbiaceae (25 spp.), Fabaceae (23 spp.), Sapindaceae (18 spp.), and Myrtaceae (17 spp.) were the most speciose families in Pacific dry forest; however, no family dominated across regions in the Pacific. The most common species by frequency and density in each region were native with the exception of Hawai‘i, which contains a high number of nonnative species. Observed and estimated (Chao 2) levels of native species richness show that New Caledonia and Fiji contain the highest species richness followed by Hawai‘i, the Marianas, and the Marquesas. There is very little overlap at the native species level among regions, with Hawaiian dry forests the most dissimilar at the native species, genus, and family level and New Caledonia and Fiji the most similar. Unlike mainland neotropical dry forest, dry forests in the Pacific contain very few deciduous species and a low proportion of wind-dispersed species. There is a high proportion of dioecious species in Hawai‘i, which is similar to the neotropics; however, other Pacific regions have fewer dioecious species. v. ill. 23 cm.; Quarterly

New Records of Butterflies from Yap Outer Islands, Micronesia: Fais Island and Ngulu, Ulithi, and Woleai Atolls.

Buden, Donald W.; Tennent, W. John — Sat, 01 Jan 2011 00:00:00 GMT

Eight species of butterflies are recorded from among four different island groups in Yap Outer Islands, Federated States of Micronesia (FSM). Five species (63%) belong to the family Lycaenidae; the three others to Nymphalidae. Hypolimnas bolina is the most ubiquitous species, being the only one recorded on all the islands. Ngulu Atoll, which has the smallest land area, also has one of the most depauperate butterfly faunas, with only two species recorded, but it is located between Palau and Yap proper, which host the richest butterfly faunas in southwestern Micronesia. Ulithi Atoll, which is nearest to potential source populations on Yap, has the largest number of species. Small island size, limited habitat diversity, and lack of sufficient host plants combined with distance from potential source populations are likely to be the main factors contributing to the small number of species on these low-lying coralline islands. v. ill. 23 cm.; Quarterly

Proposal of the Name Chaetomorpha vieillardii (Ku¨ tz.), n. comb., for a Large-Celled Tropical Chaetomorpha (Chlorophyta).

Wynne, Michael J. — Sat, 01 Jan 2011 00:00:00 GMT

Type material of Bangia vieillardii Ku¨ tz. from New Caledonia has been studied and determined to belong to the green algal genus Chaetomorpha. The name Chaetomorpha vieillardii (Ku¨ tz.), n. comb., is effected, and this binomial is proposed to serve for what has previously been known in tropical seas as C. crassa. Genuine C. crassa (C. Agardh) Ku¨ tz., based on European type specimens, has been treated by others to be conspecific with C. linum (O. F. Mu¨ ll.) Ku¨ tz. v. ill. 23 cm.; Quarterly

Trace Metal Partitioning in a Nearshore Tropical Environment: Geochemistry of Carbonate Reef Flats Adjacent to Suva Harbor, Fiji Islands.

Collen, John D.; Atkinson, Jane E.; Patterson, John E. — Sat, 01 Jan 2011 00:00:00 GMT

Namuka Reef is a broad fringing reef flat situated immediately adjacent to the populous and heavily industrialized areas surrounding Suva Harbor, Fiji Islands. Reef flat sediments are mainly very poorly to moderately sorted carbonate gravels and sands with occasional boulders and very little silt, with terrigenous sediments limited to a narrow, nearshore strip. Bulk sediment geochemical analyses show that trace metal concentrations are generally very low across the reef flat and closely similar to pristine reef areas offshore rather than to the nearby contaminated areas within Suva Lagoon. Exceptions occur close to villages, however, where sediments are enriched in Pb, As, and other trace metals, and possibly near wreck sites on the reef where Fe increases locally. These data together with those for major and minor oxides show that there is little or no movement of sediments from the rivers and deeper lagoon onto the carbonate reef flat even though extreme events such as tsunamis or cyclones affect the area. This indicates that the geomorphic separation of reef flats from adjacent contaminated environments is sufficient to prevent the introduction of solid contaminants. Reef flats may thus retain healthy ecosystems and provide resources to the community even though close to heavily contaminated areas. v. ill. 23 cm.; Quarterly

Pelagic Larval Duration and Settlement Size of Apogonidae, Labridae, Scaridae, and Tripterygiidae Species in a Coral Lagoon of Okinawa Island, Southern Japan.

Ishihara, Taiki; Tachihara, Katsunori — Sat, 01 Jan 2011 00:00:00 GMT

Pelagic larval duration and settlement sizes in species of Apogonidae, Labridae, Scaridae, and Tripterygiidae in a coral lagoon in southern Japan were examined. Sampling was conducted monthly from July 2004 to June 2005 in the coral lagoon and channel of the Oh-do Beach on Okinawa Island, Japan. Pelagic larval duration was estimated by the number of otolith increments. Mean standard length at settlement of apogonids ranged from 7.7 to 13.9 mm, and mean pelagic larval duration ranged from 14.0 to 30.6 days (14 species, 418 individuals). In labrids, mean standard length at settlement and pelagic larval duration varied greatly (mean standard length: 5.4–11.0 mm; pelagic larval duration: 18–57 days, four species, four individuals). Scarids showed consistent mean standard length at settlement and pelagic larval duration (mean standard length: 7.1–7.6 mm; pelagic larval duration: 29–42 days, five species, 25 individuals). In tripterygiids, pelagic larval duration was more consistent (range: 18–29 days, mean: 22.2e2.1 days), but mean standard length at settlement ranged from 7.8 to 10.3 mm (six species, 32 individuals). These results suggest that the pelagic larval duration of Apogonidae and Tripterygiidae (nonpelagic egg spawning) is shorter than that of Labridae and Scaridae (pelagic egg spawning), and the dispersal strategy of labrids and scarids may include wider dispersal than that of apogonids and tripterygiids. v. ill. 23 cm.; Quarterly

Prehistoric Birds and Bats from the Atiahara Site, Tubuai, Austral Islands, East Polynesia.

Worthy, Trevor H.; Bollt, Robert — Sat, 01 Jan 2011 00:00:00 GMT

The Austral Islands in French Polynesia have a depauperate land bird fauna and until recently have been little investigated archaeologically or paleontologically to know whether this is natural. Here we report an avifaunal assemblage and bones of bats of the genus Pteropus from the Archaic period (ca. A.D. 1000–1450) cultural site Atiahara, on Tubuai. Fifteen taxa are reported from the island, and a new species of rail in the genus Gallirallus is described. The data indicate that several petrel species have been extirpated from the island and that former land bird inhabitants included at least two small pigeons and a flightless rail. v. ill. 23 cm.; Quarterly

Survival of European Mouflon (Artiodactyla: Bovidae) in Hawai‘i Based on Tooth Cementum Lines

Sat, 01 Jan 2011 00:00:00 GMT

Reliable techniques for estimating age of ungulates are necessary to determine population parameters such as age structure and survival. Techniques that rely on dentition, horn, and facial patterns have limited utility for European mouflon sheep (Ovis gmelini musimon), but tooth cementum lines may offer a useful alternative. Cementum lines may not be reliable outside temperate regions, however, because lack of seasonality in diet may affect annulus formation. We evaluated the utility of tooth cementum lines for estimating age of mouflon in Hawai‘i in comparison to dentition. Cementum lines were present in mouflon from Mauna Loa, island of Hawai‘i, but were less distinct than in North American sheep. The two age estimation methods provided similar estimates for individuals aged a3 yr by dentition (the maximum age estimable by dentition), with exact matches in 51% (18/35) of individuals, and an average difference of 0.8 yr (range 0–4). Estimates of age from cementum lines were higher tha those from dentition in 40% (14/35) and lower in 9% (3/35) of individuals. Discrepancies in age estimates between techniques and between paired tooth samples estimated by cementum lines were related to certainty categories assigned by the clarity of cementum lines, reinforcing the importance of collecting a sufficient number of samples to compensate for samples of lower quality, which in our experience, comprised approximately 22% of teeth. Cementum lines appear to provide relatively accurate age estimates for mouflon in Hawai‘i, allow estimating age beyond 3 yr, and they offer more precise estimates than tooth eruption patterns. After constructing an age distribution, we estimated annual survival with a log-linear model to be 0.596 (95% CI 0.554–0.642) for this heavily controlled population. v. ill. 23 cm.; Quarterly

Excluding Nontarget Species from Brown Tree Snake, Boiga irregularis (Reptilia: Colubridae), Bait Stations: Experimental Tests of Station Design and Placement.

Sat, 01 Jan 2011 00:00:00 GMT

Bait stations with toxic baits are an emerging technology for eradication of the invasive brown tree snake (Boiga irregularis) on Guam, yet potential interferences by nontarget species are largely unknown. We tested the efficacies of three bait station designs together with three commonly used station support structures to exclude nonnative rats (roof rat, Rattus rattus; Norway rat, Rattus norvegicus; Polynesian rat, Rattus exulans) and native coconut crabs (Birgus latro). When directly presented, all species readily consumed the dead neonatal mouse baits (nontoxic) including those replicating decomposing baits in the field. When bait stations were made easily accessible by placement near ground level, all rat species were able to enter all station types, but some individual roof rats and Norway rats exhibited apparent neophobia. When stations were placed up on support structures, simulating those in the field (P1 m above ground level), numbers of station accessions by roof rats and Norway rats remained essentially unchanged, but Polynesian rats then showed almost no inclination to enter stations. However, ability to access entrances of stations ( but not interiors) when on support structures was extremely high for roof rats and appreciable for the other rat species, including Polynesians. The station type currently in widest use, when placed on chain-link cyclone fence, had the highest probability of accession.Crabs readily accessed station entrances but never interiors. The two downward-angled station designs, when placed in simulated vegetation, had the lowest probabilities of accession. In areas where nontarget species are a concern, we recommend use of either of the downward-angled station designs and suspension from vegetation wherever possible. v. ill. 23 cm.; Quarterly

Pattern of Twig Cutting by Introduced Rats in Insular Cloud Forests.

Abe, Tetsuto; Umeno, Hiromi — Sat, 01 Jan 2011 00:00:00 GMT

We examined seasonal patterns of twig cutting by the introduced black rat, Rattus rattus, on Haha-jima Island, an island in the Ogasawara (Bonin) group of Japan. Censuses were conducted along seven routes to count the number of trees damaged by twig cutting in each month. Overall, 42.6% (23/54 species) of woody species were damaged. Twig cutting was greatest in spring (March–May). Probability of damage by twig cutting was not correlated with species frequency in the vegetation. This suggests that twig cutting is associated with particular characteristics of target species. Endemic plants experienced a significantly higher probability of twig cutting than alien plants. This may be due to an evolutionary loss of plant defense mechanisms in the absence of herbivorous mammals. Because the overall proportion of individuals damaged by twig cutting was not high, the behavior is unlikely to influence the population dynamics of trees and cause vegetation change. But intense twig cutting was also found on critically endangered plants, so twig cutting by black rats could be a threat to those species. v. ill. 23 cm.; Quarterly

Role of Fire in the Germination Ecology of Fountain Grass (Pennisetum setaceum), an Invasive African Bunchgrass in Hawai‘i.

Adkins, Edith; Cordell, Susan; Drake, Donald R. — Sat, 01 Jan 2011 00:00:00 GMT

Field and laboratory studies were carried out to test factors expected to be relevant for the germination of fountain grass: (1) light; (2) emergence of fountain grass seedlings from depths of 0, 2.5, and 5 cm; (3) fire passing over exposed and buried seeds; (4) laboratory heat treatment mimicking exposure to grass fire. Both fire in the field and heat applied in the laboratory killed fountain grass seeds. In the laboratory, some seeds were killed after exposure to 75_C for 3 min, and all seeds were killed at 100_C. During the prescribed burns, temperatures at the soil surface reached at least 204_C, but temperatures at depths of 2.5 and 5 cm showed no measurable change. Light is not essential for germination of fountain grass seeds, and seedlings can emerge from depths of at least 5 cm. Both of these traits contribute to the invasive capacity of the species. Because fountain grass seeds are killed at temperatures in excess of 100_C, the species depends on its ability to resprout and quickly set seed after fire for population growth and spread. Seeds buried beneath the soil may escape exposure to fire, and substrate heterogeneity may provide refuge from temperature extremes experienced during fire. The morphology of fountain grass seeds likely inhibits burial in the soil for the most part, but there are several potential burial mechanisms. Prescribed burns could prove to be a useful tool for fountain grass control in large, degraded sites where fountain grass has invaded but only when coupled with additional control measures. v. ill. 23 cm.; Quarterly