The importance of body size to reproductive success has often been emphasized, but timing of arrival to the breeding grounds may also be important. To assess the relative roles of size and timing, we investigated the influence of life history and of behavioral and morphological traits on realized reproductive success in wild pink salmon, Oncorhynchus gorbuscha, during the 1997 and 1998 spawning seasons. Reproductive success was quantified by the number of adult offspring returning to spawn (1999 and 2000; parentage determined via DNA microsatellite genotyping). Males that arrived earlier, lived longer in the stream, and were more often observed in dominant courtship positions had significantly more offspring, although the importance of dominance was overshadowed by timing. Female reproductive success was not closely linked to any measured trait, but stabilizing selection on arrival timing and length is possible, as 1998 fish showing intermediate values of these traits were the most productive. Bear predation accounted for up to 50% of the mortality on the spawning grounds, yet did not have detectable effects on reproductive success. The absence of strong linear relationships between reproductive success and such traits as body size and fecundity may indicate that selection has driven the population to equilibrium values.

Through intentional and accidental introduction, more than 100 species of alien Ichneumonidae and Braconidae (Hymenoptera) have become established in the Hawaiian Islands. The extent to which these parasitoid wasps have penetrated native wet forests was investigated over a 1,765 m elevation gradient on windward Hawai'i Island. For [1 year, malaise traps were used to continuously monitor parasitoid abundance and species richness in nine sites over three elevations. A total of 18,996 individuals from 16 subfamilies were collected. Overall, the fauna was dominated by aliens, with 44 of 58 species foreign to the Hawaiian Islands. Ichneumonidae was dominant over Braconidae in terms of both diversity and abundance, comprising 67.5% of individuals and 69.0% of species collected. Parasitoid abundance and species richness varied significantly with elevation: abundance was greater at mid and high elevations compared to low elevation while species richness increased with increasing elevation, with all three elevations differing significantly from each other. Nine species purposely introduced to control pest insects were found, but one braconid, Meteorus laphygmae, comprised 98.0% of this assemblage, or 28.3% of the entire fauna. Endemic species, primarily within the genera Spolas and Enicospilus, were collected almost exclusively at mid-and high-elevation sites, where they made up 22.1% and 36.0% of the total catch, respectively. Overall, 75.9% of species and 96.0% of individuals are inferred to parasitize Lepidoptera larvae and pupae. Our results support previous data indicating that alien parasitoids have deeply penetrated native forest habitats and may have substantial impacts on Hawaiian ecosystems.

SummaryEstimating population abundances and patterns of change over time are important in both ecology and conservation. Trend assessment typically entails fitting a regression to a time series of abundances to estimate population trajectory. However, changes in abundance estimates from year-to-year across time are due to both true variation in population size (process variation) and variation due to imperfect sampling and model fit. State-space models are a relatively new method that can be used to partition the error components and quantify trends based only on process variation. We compare a state-space modelling approach with a more traditional linear regression approach to assess trends in uncorrected raw counts and detection-corrected abundance estimates of forest birds at Hakalau Forest National Wildlife Refuge, Hawai‘i. Most species demonstrated similar trends using either method. In general, evidence for trends using state-space models was less strong than for linear regression, as measured by estimates of precision. However, while the state-space models may sacrifice precision, the expectation is that these estimates provide a better representation of the real world biological processes of interest because they are partitioning process variation (environmental and demographic variation) and observation variation (sampling and model variation). The state-space approach also provides annual estimates of abundance which can be used by managers to set conservation strategies, and can be linked to factors that vary by year, such as climate, to better understand processes that drive population trends.

Camp, Richard J.; Farmer, Chris; Brinck, Kevin W.; Leonard, David L.; and Stephens, Robert M., "Response of palila and other subalpine Hawaiian forest bird species to prolonged drought and habitat degradation by feral ungulates" (2013 Extinction has claimed half of all historically-known Hawaiian passerines, and today many extant species are increasingly threatened due to the combined effects of invasive species and climate change. Habitat disturbance has affected populations of feeding specialists most profoundly, and our results indicate that specialists continue to be most vulnerable, although even some abundant, introduced, generalist species also may be affected. Surveys of passerines during 1998-2011 in subalpine woodland habitat on Mauna Kea Volcano, Island of Hawai 0 i, revealed that the abundance of the critically endangered palila (Loxioides bailleui), a seed specialist, declined by 79% after 2003. The 0 akiapō lā 0 au (Hemignathus munroi), an endangered specialist insectivore, was not detected in the survey area after 1998. The Hawai 0 i 0 amakihi (Hemignathus virens virens), a generalist feeder and the most abundant species on Mauna Kea, was the only native species to maintain a stable population. The Japanese white-eye (Zosterops japonicus), a wellentrenched generalist and one of the three most common introduced species, declined. Drought prevailed in 74% of months during 2000-2011, and dry conditions contributed to the recent decline of the palila by reducing the annual mā mane (Sophora chrysophylla) seed pod crop, which influences palila breeding and survival. Sustained browsing by introduced ungulates also lowered habitat carrying capacity, and their elimination should reduce the effects of drought and promote forest restoration. Our results illustrate how the feeding ecology of a species can influence its response to interacting environmental perturbations, and they underscore the value of long-term monitoring to detect population trends of sensitive species.Published by Elsevier Ltd.