Genetic Stock Structure of Green Turtle (Chelonia mydas) Nesting Populations Across the Pacific Islands
Peter H. Dutton, Michael P. Jensen, Karen Frutchey, Amy Frey, Erin LaCasella, George H. Balazs, Jennifer Cruce, Alden Tagarino, Richard Farman, and Miri Tatarata, 451
Abstract: More than two decades have passed since the first studies documenting genetic population structure of green turtles (Chelonia mydas) were published. Since then many more have followed and characterization of the genetic structure of green turtle rookeries now covers most of the global distribution of the species, benefitting conservation of this threatened species worldwide. However, important data gaps still exist across a large part of the western and central Pacific Ocean (WCPO). This large area is made up of hundreds of scattered islands and atolls of Micronesia, Melanesia, and Polynesia, most of which are remote and difficult to access. In this study, we assessed stock structure of green turtles throughout the WCPO using mitochondrial (mt) DNA from 805 turtles sampled across 25 nesting locations. We examined whether sequencing longer fragments (770 bp) of the control region increases resolution of stock structure and used genetic analysis to evaluate level of demographic connectivity among island nesting populations in the WCPO. We identified a total of 25 haplotypes characterized by polymorphism within the 770 bp sequences, including five new variants of haplotypes that were indistinguishable with shorter 384 bp reads from previous studies. Stock structure analysis indicated that rookeries separated by more than 1,000 km were significantly differentiated from each other, but neighboring rookeries within 500 km showed no genetic differentiation. Results presented in this paper establish that sequencing of longer fragments (770 bp) of the control region does in some cases increase resolution and that there are at least seven independent stocks in the region.
Modeling Sea Turtle Maturity Age from Partial Life History Records
Kyle S. Van Houtan, Stacy K. Hargrove, and George H. Balazs, 465
Abstract: In the absence of direct observations, demographic traits such as age and reproductive status may be modeled through proxies. We examined 35 yr of over 10,000 captures of Hawaiian green turtles (Chelonia mydas) and compared results from skeletochronology studies with mark-recapture records. For 109 turtles that were captured as juveniles and later observed nesting, we estimated maturity age first from skeletochronology-based models of age to length and second by estimating age at first capture using skeletochronology and then adding the time elapsed to first nesting. The second method involving mark-recapture gave younger and less variable age estimates. From these data we developed a scaling rule that calculates that females first bred at 23 yr (95% interval: 16.8–28.1). This result was corroborated by tag returns in the Caribbean and Hawai‘i showing that green turtles first nest at 16–20 yr. We validated this approach using life table models, successfully reconstructing four decades (1973–2012) of nesting surveys at East Island, French Frigate Shoals. We then compared our results with observed somatic growth rates, which suggest that nearshore studies may sample an atypical subset of the population that is chronically sedentary and slow growing. When exact life history traits are unknown, we recommend consulting multiple lines of evidence and independently validating proxy studies.
Review and Key to Aphids (Hemiptera: Aphididae) in Micronesia
Ross H. Miller, Julie Anne M. Duay, Keith S. Pike, Eric Maw, and Robert G. Foottit, 479
Abstract: Aphid species from 11 of the major islands of Micronesia ranging from Majuro, Republic of the Marshall Islands, in the east to Koror and Babeldaup, Republic of Palau, in the west, are documented based on 1,691 collections. Other islands sampled included Yap, Kosrae, and Chuuk in the Federated States of Micronesia; Saipan, Tinian, and Rota in the Commonwealth of the Northern Mariana Islands; and the Territory of Guam. Host-plant associations were documented at each collection site. Thirty-five aphid species were collected from 139 plant species in 43 different plant families. None of the aphids collected is indigenous to Micronesia. A key to the identification of the aphid species is provided.
Edge Effects Disrupt Vertical Stratification of Microclimate in a Temperate Forest Canopy
Raphael K. Didham and Robert M. Ewers, 493
Abstract: Forest edge structure plays a key role in modulating microclimatic edge responses. However, empirical evidence for this is derived almost entirely from ground-based measurements, rather than measurements across the vertical canopy profile. Intuitively, canopy organisms are not only exposed to altered lateral-edge processes but also vertical influences from the hot, dry canopy edge above. The question then is “what is the influence of edge formation on vertical stratification of edge microclimate?” Here, we undertake a novel test of edge influence on vertical stratification of microclimate across the full vertical profile from ground level to upper canopy in a New Zealand temperate rain forest. We hypothesized that there would be a breakdown of vertical stratification at the edge and “compression” of the abiotic envelope experienced by organisms. We deployed 25 data loggers at five heights from canopy down to ground level (0, -2, -4, -8, -16 m) at each of five distances from edge (0, -2, -4, -8, -16 m) and quantified incident light, air temperature, and vapor pressure deficit relative to an external control. As predicted, we found strong evidence of a breakdown of vertical stratification at the edge for all microclimate variables. In generalized linear mixed models there was a significant interaction between vertical height and distance from edge, with microclimate differentials increasing in magnitude from edge to interior at ground level but decreasing in magnitude from edge to interior at canopy level. Attenuation of edge effects was lower above ground level, suggesting that past evidence of microclimatic edge effects based on ground-level measurements may underestimate the full extent of edge influence on vertical stratification of microclimate in forest remnants.
Influences of N-Fixing and Non-N-Fixing Vegetation and Invasive Fish on Water Chemistry of Hawaiian Anchialine Ponds
B. D. Dudley, R. A. MacKenzie, T. S. Sakihara, H. Dulaiova, C. A. Waters, R. F. Hughes, and R. Ostertag, 509
Abstract: In coastal waters, it remains unclear how terrestrial invasive species might alter nutrient availability and thus affect bottom-up control of primary production. Anchialine ponds are tidal- and groundwater-fed coastal water bodies without surface connections that provide convenient model systems in which to examine terrestrial to aquatic nutrient flow. To investigate how N-fixing and non-N-fixing terrestrial vegetation and invasive consumers affect water quality, we compared dissolved nutrient concentrations and physicochemical parameters among Hawaiian anchialine ponds surrounded by: (1) the nonnitrogen (N)-fixing tree Thespesia populnea (milo), (2) the exotic N-fixing tree Prosopis pallida (kiawe), (3) no tree cover, and (4) no tree cover but containing populations of invasive poeciliid fish. Average (±1 SE) concentration of dissolved inorganic nitrogen (DIN) across all ponds (51.15 µM ±3.1; n = 17) was high, but there was no discernible pattern among pond types. Model results suggest that leaf litter breakdown from the exotic N-fixing tree contributed <0.02% of total dissolved nitrogen (TDN) in the water column at high tide. However, additions of phosphorus (P), especially from litter of non-N-fixing T. populnea, resulted in ratios of DIN to soluble reactive phosphorus (SRP) that varied between 4.5:1 and 35:1 across pond types. Our study suggests that: (1) DIN concentrations were more dependent on watershed-scale N inputs than local tree cover or the presence of poeciliids, (2) low water residence times in these ponds reduce effects of local biota on water nutrient chemistry, and (3) P from anthropogenic inputs and/or biota cause alterations to DIN:SRP ratios in anchialine pond water that may potentially alter primary production rates in these coastal ecosystems.
Assessing Status, Capacity, and Needs for the Ex Situ Conservation of the Hawaiian Flora
Lauren Weisenberger and Matthew J. Keir, 525
Abstract: The flora of the Hawaiian Islands has one of the highest rates of endemism in the world, and over half of all taxa are at risk of endangerment or extinction. When in situ management alone cannot protect plant populations, maintaining viable germplasm using ex situ storage methods will prevent species extinctions. Germplasm collections with high conservation value are genetically diverse, representative of taxa and populations, and have a well-documented history in cultivation. Ex situ facilities and conservation agencies were surveyed to determine if existing ex situ capacity was sufficient to represent Hawai‘i’s species of conservation importance (SCI) and to identify limiting factors. SCI were defined and their representation in ex situ collections quantified, the number of wild plants and populations were estimated, and the attempted ex situ methods were recorded. There are 724 SCI, 528 of which are located in at least one facility. Sixty-four percent of the secured taxa are represented by collections from only 10% or fewer of the wild plants. Seed banks have secured more SCI, and with better in situ representation, than any other ex situ method. Seventy-eight percent of SCI have seeds with long-term storage potential. Existing seed storage facilities are currently inadequate for representing all SCI and should be expanded. SCI with low long-term potential in conventional seed storage can be represented in cryopreservation, micropropagation facilities, nurseries, and botanical gardens. Recommendations include establishing a network to coordinate collections, improve data management, and draft conservation plans with ex situ collection goals. This type of assessment can be applied to other regions that do not have a unified and consistent method of tracking ex situ representation.
Genetic Diversity of the Endangered Endemic Hawaiian Genus Kokia (Malvaceae)
Alison R. Sherwood and Clifford W. Morden, 537
Abstract: Genetic diversity of all three extant species of the Hawaiian endemic tree genus Kokia was examined using analyses of RAPD markers. All three species are federally endangered, two (K. cookei and K. drynarioides) critically so, and one (K. kauaiensis) is rare but with several populations. Samples extracted were PCR amplified with 10 primers to yield 115 genetic markers. Analyses indicate that genetic variation is present in all three species; a surprising result given that K. cookei survives only from self-fertilized propagules of the single surviving individual that was grafted on to the root stock of a related species, K. drynarioides. Principal coordinates and cluster analyses based on RAPD markers indicate that although K. kauaiensis has substantial genetic variation, samples are clearly separate from the other two species of the genus. In contrast, K. cookei and K. drynarioides collections are more similar but still distinguishable when analyzed separately. Presence of substantial genetic variation lends optimism to the eventual recovery of K. kauaiensis through conservation efforts. Combinations of RAPD primers are suggested that reveal diagnostic alleles for each of the three extant species and can thus be used for species identification.
Response of Wedge-tailed Shearwaters (Puffinus pacificus) to Eradication of Black Rats (Rattus rattus) from Moku‘auia Island after Reinvasion1
Amarisa Marie, Eric A. VanderWerf, Lindsay C. Young, David G. Smith , Jakob Eijzenga, and Michael T. Lohr, 547
Abstract: Moku‘auia is a 5-ha island off northeastern O‘ahu, Hawai‘i, that supports several thousand nesting Wedge-tailed Shearwaters (Puffinus pacificus) and several species of migratory shorebirds and is critical habitat for the federally endangered ‘ohai plant (Sesbania tomentosa). The island is separated from Mālaekahana State Recreation Area on O‘ahu by a channel 230 m wide and 1 m deep and receives numerous human visitors. Black rats (Rattus rattus) were first documented on Moku‘auia in 1967 and were eradicated in the 1990s, but rats recolonized the island and were eradicated again in 2006. We re-eradicated black rats in November 2011 following another recolonization, using snap traps and diphacinone in bait boxes spaced 25 m apart. Pre-eradication, 80% of tracking tunnels contained rat tracks. After 14 days, no more rats were trapped, bait take dropped to almost zero, and no rats have been detected since. Eradication of rats resulted in a doubling of Wedge-tailed Shearwater reproduction in 2006 and 2012 and is expected to enhance regeneration of native plants. Black rats may recolonize Moku‘auia periodically in the future because of its proximity to O‘ahu and the frequency of human visitation, but its small size and simple terrain make rats easy and inexpensive to eradicate, and the natural resources present warrant continued management.
Abstract: Status of Indo-Pacific bottlenose dolphins (Tursiops aduncus) around Jeju Island, Korea, was assessed using potential biological removal (PBR) and mortality data. Considering the 2009 estimated abundance of Indo-Pacific bottlenose dolphins in this area (114; 95% CI= 109-133), the PBR for Indo-Pacific bottlenose dolphins calculated as one individual, based on the minimum population estimate (109), one-half of the maximum theoretical net productivity rate (0.02), and the recovery factor (0.5). Estimated mean level of anthropogenic mortality from 2009 to 2010 was nine individuals. Based on these numbers the status of this stock was considered as strategic. Primary sources of anthropogenic mortality were bycatch and incidental live capture in pound nets. Most incidentally live-captured individuals were illegally sold to aquaria for dolphin shows. Because of the strategic status of this population, it is urgently necessary to reduce the amount of bycatch and incidental live capture in pound nets. Further study is needed using population viability analysis to assess the likelihood of long-term survival of this population.
Swimming Crabs (Crustacea: Brachyura: Portunoidea) of Easter Island
Christopher B. Boyko and Alyssa Liguori, 563
Abstract: The portunoid fauna of Easter Island is reviewed, based on historical records and material collected by the Science Museum of Long Island Easter Island Expedition of 1998–1999. Previously, only two portunoid taxa identified to the species level were recorded from the island. This work reports on six species of portunoids: Ovalipes elongatus Stephenson & Rees, 1968 (new record), Laleonectes nipponensis (Sakai, 1938) (new record), Portunus pubescens (Dana, 1852), Thalamita auauensis Rathbun, 1906 (new record), T. bevisi (Stebbing, 1921) (new record), and T. seurati Nobili, 1906 (new record). Specimens tentatively referred to Thalamita minuscula Nobili, 1906, are also discussed, but this taxon may represent the juvenile form of T. seurati. The new records from the island all represent large range extensions for each species. Color notes are provided for four species. The first pleopod of the male of O. elongatus is illustrated for the first time, and the species’ potential as an invasive taxon is discussed.
A New Species of Kumanoa (Batrachospermales, Rhodophyta) from Kōke‘e State Park, Kaua‘i, Hawai‘i
Alison R. Sherwood, Casey A. Jones, and Kimberly Y. Conklin, 577
Abstract: A new freshwater red alga is described from Kōke‘e State Park on the island of Kaua‘i, Hawai‘i. The alga is a member of the genus Kumanoa, which was recently established to accommodate two sections of the large freshwater red algal genus Batrachospermum. Specimens are shown to be unique relative to all other confirmed members of the genus based on both morphological comparisons and molecular phylogenetic analyses of a concatenated alignment of three molecular markers. Kumanoa alakaiensis Sherwood, Jones, & Conklin, n. sp., differs from the only other known Hawaiian representative of the genus, K. spermatiophora, which is endemic to Maui, in having a much smaller, cartilaginous thallus; having reduced subspherical- to slightly obconicshaped whorls; and in lacking spermatiophores. Phylogenetic analyses support K. alakaiensis as a distinct and early diverging lineage within the genus, and as sister to a large clade containing all but three species characterized to date. This species description brings the total number of recognized freshwater red algal species in Hawai‘i to eight, three of which are believed to be endemic.
Index to Volume 68, 587
Association Affairs, 593