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We observed development in surf smelt (Hypomesus pretiosus) embryos from 24 hours post fertilization through hatch, at water temperatures of 12.52 oC (SD = 0.22) to 22.37 oC (SD = 1.14). Our system mimicked the tidal cycle by draining incubation chambers of water for 12 hours a day in concert with a photoperiod that mimicked a seasonal light/dark cycle of 16 hours of light and eight hours of darkness. The first detected heartbeat was documented at 62 degree days, partial hatch occurred by 187 degree days, and all remaining live eggs had hatched by 225 degree days. Developmental milestones were documented with micro photography and videography. Various developmental stages were illustrated in pen and ink for documentation. This work was used to gather developmental baseline data for the species.
Key Points:
We documented in photos, video, and illustrations, the embryological development of surf smelt.
This lays the groundwork for future studies, including ecotoxicology, ocean acidification, and effects of shoreline modification.
Joint Base Lewis–McChord, Washington, has the largest population of ponderosa pine (Pinus ponderosa) west of the Cascade Range in the Pacific Northwest. Field mapping showed a modern geographic range of approximately 13,270 ha. The ages and locations of the largest, oldest pines indicated that at the time of Euro-American settlement in the mid-1800s, most pines grew in a single area of approximately 1,730 ha within a landscape of woodland, savanna, and grassland maintained by Native American fire. After settlement ended burning, conifer forest replaced much of the original vegetation and the range of pine expanded. I repeatedly measured permanent plots over an 11-year period (2007–2018) within the two forest types with pine: Closed Forest (mean canopy cover ≥ 60%) dominated by Douglas-fir (Pseudotsuga menziesii), and Woodland/Savanna (mean cover 5–59%) often mixed with Douglas-fir and Oregon white oak (Quercus garryana). Pine basal area and density were similar between forest types. Overstory pines in Woodland/Savanna had a larger diameter growth and crown ratio, lower height and height:diameter ratio, and averaged 40 years younger than those in Closed Forest. Pine regeneration was scarce or absent in Closed Forest, except for a pulse in 2018. The only notable temporal trend was log accumulation in Woodland/Savanna following a wildfire. Pine diameter and age distributions showed an increasing deficit of young pines over time. Major impediments to pine regeneration are competition from Douglas-fir in Closed Forest, competition from a non-native shrub Scotch broom (Cytisus scoparius) in Woodland/Savanna, and fires that burn hotter than historic fires. Active management will be necessary to perpetuate this pine population long-term in Woodland/Savanna; it may not be possible to do so in Closed Forest.
Key Points
Joint Base Lewis–McChord has the largest population of ponderosa pine west of the Cascade Range in the Pacific Northwest.
Pine is much more abundant, grows faster, and has proportionally bigger crowns in woodlands and savannas than in dense conifer forests.
Scarce pine regeneration in dense conifer forests means that pine will gradually disappear from the overstory, while in woodlands and savannas, full replacement by pine regeneration of existing overstory pine mortality is unlikely. Active management is necessary to temporarily retain mature pines in dense forest overstories and maintain pine of all sizes long-term in woodlands and savannas.
We examined the seasonal movements of adult yellow perch (Perca flavescens) between a small, shallow lake (Lake Union) and a large, deep lake (Lake Washington). Lake Union is the largest part of the Lake Washington Ship Canal (LWSC), a narrow waterway between Lake Washington and Puget Sound. Yellow perch were implanted with acoustic tags that had a battery life of at least 460 days. All tagged yellow perch were captured and released in Lake Union in the summer of 2020 or 2021. Movements were monitored primarily with 14 stationary receivers that were deployed at key locations between the two lakes. Additional information was obtained from mobile tracking and other stationary receivers in Lake Washington. Of the 47 fish tagged, we were able to get seasonal movement data on 28 fish. Twenty-three (82%) of them left Lake Union and moved into Lake Washington while the other five (18%) remained in the LWSC. Most movements from Lake Union to Lake Washington occurred in September or October when water temperatures were decreasing. Return movements from Lake Washington to Lake Union had variable timing. Migrations between Lake Union and Lake Washington usually took just a few hours and took place day or night. The farthest observed distance moved from the release site was approximately 16 km. Within Lake Washington, tagged yellow perch were found over a broad area in the northern two-thirds of the lake. Overall, tracking results indicated yellow perch can make extensive migrations between the two lakes.
Adult yellow perch from Lake Union were implanted with acoustic tags to monitor their seasonal and diel movement patterns.
Most yellow perch left Lake Union in the fall as temperatures were declining and migrated to Lake Washington where better overwintering conditions were present.
Migration between Lake Union and Lake Washington usually took just a few hours and took place day or night.
Biochar can be used as a soil amendment to restore degraded soils, sequester carbon, and increase soil water holding capacity and plant available water following harvest operations in a forest. On-site production and utilization of biochar is being explored as a forest management tactic. One benefit of the practice is the sequestration of carbon by using unmerchantable forest biomass to produce biochar. Forest insects may be exposed to biochar when the material is applied to surface organic horizons and downed trees. How biochar affects insects' ability to locate and utilize downed woody material in the forest is undetermined. Two field experiments with freshly downed sections (bolts) of ponderosa pine (Pinus ponderosa Lawson & C. Lawson) were conducted to determine the potential impact of applied biochar on insect communities utilizing the bolts. In the first experiment, bolts were baited with a pheromone lure and biochar was applied at a rate equivalent to 2,914 kg·ha-1 (1.30 tons·acre-1). The biochar treatment did not interfere with attack or emergence of the pine engraver Ips pini (Say) (Coleoptera: Curculionidae: Scolytinae) compared to untreated control bolts. In the second experiment, biochar applied at a rate equivalent to 5,604 kg·ha-1 (2.50 tons·acre-1) lowered insect species richness compared to non-treated bolts. In addition, one species, red turpentine beetle Dendroctonous valens (LeConte) (Coleoptera: Curculionidae: Scolytinae), was more abundant in non-treated bolts compared with biochar-treated bolts. Utilization of bolts by other insect taxa such as longhorn beetles (Coleoptera: Cerambycidae) was similar in non-treated and biochar-treated bolts.
Cacti are iconic members of arid ecosystems. Pediocactus nigrispinus is a species of cactus endemic to the Pacific Northwest and has been listed as a sensitive species due to its vulnerability to habitat loss. Best conservation methods for this species are poorly understood, due in part to a limited understanding of its demography and habitat associations that may help define its occurrence. A demographic study from four plots in Washington State was implemented in 2016 to provide a baseline of the population dynamics for P. nigrispinus and to enhance conservation efforts for this sensitive species. Five years of size, fecundity, and survival information for the cactus were recorded. A stochastic analysis was performed to assess survival and fecundity rates in relation to different climatic variables. To better understand the cacti's limited habitat, biotic and abiotic associations were assessed in an additional 16 plots throughout Washington and Oregon by spatial analysis of soil and climatic variables and in situ assessment of vegetation and ground cover associations. These variables were then compared with population density, overall size of the individuals, and number of fruits to assess how changes in associations may correlate with changes in these traits. The demographic study found no juvenile recruitment and a declining population over the four years of analysis regardless of variation in annual precipitation. The association analysis found no correlation between population density or fecundity and biotic or abiotic associations but indicated higher fruit production in Oregon than in Washington. With the declining population and narrow endemism of the species observed, further monitoring and study for conservation efforts are recommended.
Key Points
Plant community and microbial associations were similar for P. nigrispinus throughout its range in Oregon and Washington.
No juvenile recruitment and a declining population size were observed for P. nigrispinus over four years.
A small increase in survival of adults in the medium size class could lead to stabilization of the P. nigrispinus population.
The Northern Pikeminnow Ptychocheilus oregonensis is a piscivorous cyprinid native to western North America. Information on the best structure for estimating the age of Northern Pikeminnows is a key knowledge gap that may limit inquiries on management efforts. Thus, the objective of this study was to evaluate between-reader precision and concordance between age estimates for lapilli otoliths and pectoral fin rays from Northern Pikeminnows. Age estimates from lapilli otoliths were compared to those from pectoral fin rays of 150 Northern Pikeminnows captured from Lake Cascade, Idaho, in April–May 2022. Exact percent agreement of estimated ages between the readers was higher for fin rays (75.3%) than otoliths (50.0%), with a mean coefficient of variation of 3.5 and 8.7, respectively. Readers also assigned a confidence rating (0–3; higher value reflects higher confidence in age estimate) to each structure. Confidence ratings were higher for fin ray age estimates (mean ± SD; 1.6 ± 0.6) than otolith estimates (1.1 ± 0.7) between readers. A consensus age was estimated for each structure and fish. Agreement between consensus age estimates for otoliths and fin rays was 26.7% with a coefficient of variation of 14.0. Our findings suggest that fin rays were easier to collect, process, and read than otoliths, and resulted in more precise age estimates than otoliths. Results from our study provide guidance on the best structures for estimating the age of Northern Pikeminnows that can be used to inform management efforts.
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