Invasion of native communities by alien species is one of the main threats to biodiversity. This threat is particularly high on isolated tropical islands, with the Hawaiian Islands being one of the foremost examples of this phenomenon. The Kīpahulu Biological Reserve on the island of Maui provides a unique opportunity to study how alien plant species establish and spread into native communities. The reserve covers a wide altitudinal range and has been surveyed multiple times. We analyzed the spatiotemporal dynamics of alien plant species invasion in the forest of the valley between 1945 and 2018. At the time the reserve was created, most of the valley was relatively free of alien plant species. Extensive management, including fencing to exclude ungulates, was conducted during the 1980–1990s to stop the invasion by alien plant species occurring since the 1970s. Today, only the forest located in the upper part of the valley (>1400 m) is nearly free of alien plant species. Despite management efforts, the middle portion of the valley (between 960 and 1400 m) is in the process of being invaded by Clidemia hirta (Melastomaceae), Hedychium gardnerianum (Zingiberaceae), and other invasive plants. Although C. hirta and H. gardnerianum were detected at an incipient stage in the 1980s, those species invaded a large part of the Kīpahulu valley. This highlights the importance of control of alien plants following early detection, especially in areas where initial numbers and densities are low. Additional management efforts are urgently needed to limit alien species invasions into one of the last relatively pristine wet forests of Hawai‘i.

Most tropical islands have limited water supply due to the small size of their watersheds and aquifers, unique geology, and distribution of rainfall; each affecting the reliability of water resources for meeting agricultural needs. To improve water supply, reservoirs provide critical storage of surface water. However, climate-driven shifts in the distribution, intensity, and amount of rainfall will alter runoff that feeds reservoirs. Mass-balance modeling was used to evaluate the effects of various management constraints on water availability for the Wahiawā Reservoir (O‘ahu, Hawai‘i) as well as the impact of 20% less dry season rainfall and stream flow to assess the effect of projected climate change on maintaining: (1) a minimum downstream flow; (2) a minimum agricultural supply; (3) a minimum and maximum reservoir level; and (4) a combination of minimum downstream flow and minimum agricultural supply. Under current climate conditions, maintaining a minimal downstream water release could be met with minimal consequences for agricultural supply and reservoir level. However, both agricultural supply and downstream flow had to be reduced during dry periods to keep the reservoir level above a minimum level. Maintaining a minimum downstream flow resulted in a 4.2% reduction in mean agricultural supply and 2.2% reduction in mean reservoir elevation compared to baseline conditions. By contrast, a 20% reduction in dry season water inputs resulted in a 17.8% reduction in mean agricultural supply in the minimum downstream flow scenario compared to current rainfall conditions. Furthermore, the number of days the reservoir level dropped below the minimum needed for a fishery increased (range 1.15–25×) across scenarios compared to baseline. Successful management of surface water within a social-ecological system will be challenged by the increasing unpredictability of rainfall.

Large-scale green tide disasters have been occurring for more than 10 years in China, with serious ecological consequences. However, limited research has focused on epiphytes that feed on macroalgae. In this study, amphipods were found living on the surface of Ulva lactuca, a green-tide-forming alga, around Gouqi Island, China. Through morphological and molecular methods, the amphipods were identified as Ampithoe lacertosa Bate, 1858, which has not previously been recorded in China. Sequence information about cytochrome c oxidase subunit I (mitochondrial COI) gene from China was compared to sequences reported from 5 coastal countries around the Pacific region. Network diagrams, phylogenetic trees and other methods of analysis revealed evidence of genetically distinct subspecies in the northeastern and northwestern Pacific. We believe that research on herbivorous amphipods will provide preventative strategies and control measures against green tide algae. International cooperation among Asian and North American biologists within the Pacific region will lead to a better understanding of the family Ampithoidae in the future.

Although part of the life history of loggerhead turtles (Caretta caretta) in the northwest Pacific population has been documented, there is still a paucity of data regarding their spatiotemporal ecology at the local level. The Sanriku Coast is known to be the high-latitude foraging grounds (39° N) for loggerhead turtles of the northwest Pacific population. This site is located far north from the northernmost loggerhead rookeries (>400 km) and more than 10 years of surveys have found that loggerhead turtles migrate there only in the summer. To better understand the spatiotemporal ecology of this population along the Sanriku Coast, the present study investigated the sex of 164 loggerhead turtles captured as bycatch along the Sanriku Coast between 2013 and 2017 by measuring the external morphology and serum testosterone concentrations. These analyses suggested that most of the adult-sized turtles in the Sanriku foraging grounds were males (few females), whereas both sexes of immature-sized turtles migrated to this Coast. This is possibly because migration to the Sanriku Coast is restricted to summer due to the seasonal sea surface temperature shift, and this period overlaps with the nesting period. Therefore, only immature turtles and adult males may be able to migrate. Understanding sex differences in spatiotemporal ecology should contribute to conservation practice in this population, where global warming, together with the turtle's temperature-dependent sex determination, can be expected to reduce the proportion of male hatchlings in the future.

Anthopleura mariae sp. nov. is a new species of sea anemone (Actiniaria: Actiniidae) from the rocky intertidal of Punta Morro, Baja California, and Punta Eugenia Baja California Sur, México. This species is characterized by a column with verrucae arranged in longitudinal rows from margin to limbus with a red spot atop each verruca, as well as the presence of more than two siphonoglyphs and the lack of directive mesenteries. Differences between Anthopleura mariae sp. nov. with other species of the genus are discussed. This is the sixth species of Anthopleura documented for the Mexican Pacific.

Three species of Meristogenys frogs (Ranidae) from Borneo, Malaysia were examined for helminths: Meristogenys orphnocnemis (n = 8), M. poecilus (n = 5), and M. whiteheadi (n = 8). We found three species of Nematoda: Cosmocerca ornata, Rhabdias multiproles, and Abbreviata sp. (larvae in cysts). Both C. ornata and R. multiproles are old world in distribution. The most numerous helminths were Abbreviata sp. in M. whiteheadi. The three species of Meristogenys are parasitized by generalist helminths that also infect other species of anurans. Five new host records are reported.

Sponges are ecologically important components of many marine ecosystems and are abundant benthic fauna on coral reefs. Mycale grandis is an alien invasive sponge found on many partially degraded shallow water coral ecosystems in Hawai‘i. Mycale grandis is known to compete spatially with dominant native reef building coral such as Montipora capitata and Porites compressa. Since its appearance in the late 1990s, M. grandis has established itself in a number of coral reef ecosystems around the main Hawaiian Islands. Within south Kāne‘ohe Bay, sponge coverage in 2014–2017 ranged from 2.1% on fringing reefs to 32.3% within the mangrove habitat along the northern edge of Coconut Island, which is similar to coverage found in 2006–2007 surveys. Sponges are prolific filter feeders and pump seawater for the dual purpose of obtaining resources and removing metabolic wastes, and thus process large amounts of water in their environment. Mycale grandis pumps 0.0027 L seawater s^–1 L^–1 sponge, equivalent to 115 times its own volume per day. These pumping rates were combined with biomass estimates, depth, and circulation parameters in south Kāne‘ohe Bay to show that M. grandis can cycle a substantial amount of the overlying water column and therefore has the potential to influence the biogeochemistry of overlying reef water in south Kāne‘ohe Bay.

Fifteen species of reptiles are recorded from among the nine northernmost atolls in the Republic of the Marshall Islands (RMI): 3 sea turtles, 10 lizards (3 geckos, 6 skinks, 1 monitor lizard) and 1 typhlopid snake. None is endemic to the Marshalls and all are widely distributed in Micronesia and, in many cases, well beyond. The Common House Gecko, Hemidactylus frenatus, Mariana Monitor, Varanus tsukamotoi, and Brahminy Blindsnake, Indotyphlops braminus, probably were introduced in recent times, but to what extent the other species arrived by natural dispersal, or, alternatively, by human-assisted transport at various times since the initial settlement of the islands about 2,000 years ago, is unknown. The 126 specimens of lizards collected from among eight of the atolls during March/April 2019 include the first records of terrestrial reptiles from Ailinginae Atoll, and the first records of Hemidactylus frenatus from Rongelap, Bokak, and Utirik Atolls, Gehyra oceanica from Rongelap and Taka Atolls, and Lepidodactylus lugubris from Utirik Atoll. Numerous other distribution records obtained from online databases—with the vast majority previously unreported in the literature—are included along with the earliest collection date in the RMI of H. frenatus and a revised early collection date for I. braminus.