11,500 y of human–clam relationships provide long-term context for intertidal management in the Salish Sea, British Columbia

Historical ecology can provide insights into the long-term and complex relationships between humans and culturally important species and ecosystems, thereby extending baselines for modern management. We bring together paleoecological, archaeological, and modern clam records to explore the relationship between humans and butter clams (Saxidomus gigantea) throughout the Holocene in the northern Salish Sea of British Columbia, Canada. We compare butter clam size and growth patterns from different temporal, environmental, and cultural contexts spanning 11,500 y to present. Butter clam size and growth were restricted in early postglacial times but increased over the next few millennia. During the early-Late Holocene, humans took increasing advantage of robust clam populations and after 3.5 ka, began constructing clam gardens (intertidal rock-walled terraces). Environmental and cultural variables, including coarse substrate, stabilized sea surface temperature, and the presence of a clam garden wall, increased clam growth throughout the Holocene. Measurements of clams collected in active clam gardens and deposited in middens suggest that clam gardens as well as other mariculture activities enhanced clam production despite increased harvesting pressure. Since European contact, decline of traditional management practices and increases in industrial activities are associated with reduced clam size and growth similar to those of the early postglacial clams. Deeper-time baselines that more accurately represent clam population variability and allow us to assess magnitudes of change throughout time as well as the complex interactions among humans and clams are useful for modern marine resource management.

Electrodeposition of Prussian blue films on Ni3Si2O5(OH)4 hollow nanospheres and their enhanced electrochromic properties

Porous PB films were electrodeposited on Ni3Si2O5(OH)4 hollow nanospheres, resulting in enhanced electrochromic properties due to the coarse substrate.

Improving Conservation through Cultivation: Nine Container Substrates Influence Growth of a Rare Cycad, Zamia pumila L.

Cycads comprise the most threatened major group of plants on earth and many species require horticultural assistance to ensure their survival. Appropriate container substrate properties, especially relatively high air space content, are crucial to successful cultivation of most cycads from seed. Cycad substrates in common use include substantial portions of organic materials that will decompose over time, reducing aeration. At Montgomery Botanical Center, novel inorganic substrates have improved survival and growth of several very rare and challenging Zamia species, suggesting the need for a rigorous evaluation of different inorganic container substrates. Effects of 1) coarse silica sand (6/20 grade); 2) Fafard (a peat/perlite mix); 3) perlite (expanded volcanic glass); 4) pumice (volcanic rock); 5) Turface (calcined clay); 6) Profile (calcined clay); 7) a 50% sand (6/20): 50% Profile mix; 8) Permatil (calcined slate); or 9) Axis (calcined diatomaceous earth) on growth of Zamia pumila L. seedlings (grown from seed of Dominican Republic provenance) were evaluated. Growth parameters were measured after 18 months. Sand produced significantly higher total dry weight and leaf area than all other substrates. A combination of at least 18% air space combined with little coarse material (sand) or with some coarse material combined with enough smaller particles to fill part of the large pores created by coarse material (Fafard) likely contributed to better growth in these compared with the other seven substrates. The other substrates may have been either too coarse, leading to excessively large pores, which are known to inhibit growth in some plants if the pores are much larger than fine root diameters, or too fine (i.e., too low of an air space percentage). The fine roots of Zamia can be less than 1 mm in diameter, whereas higher proportions of coarse substrate particles over 4 mm in diameter inhibited growth, possibly by creating excessively large pores. In contrast, higher proportions of fine substrate particles of 0.25 to 0.5 mm were beneficial to growth.

Trophic organization and fish assemblage structure as disturbance indicators in headwater streams of lower Sorocaba River basin, Sao Paulo, Brazil

Studies that investigate the relationship patterns between environmental structure complexity and fish fauna provide crucial information to stream restoration efforts. In order to test the hypothesis that streams with more complex environmental structure sustain more diverse and functionally more complex fish communities we sampled fish fauna from Sorocaba River headwater stream reaches (SE - Brazil). Reaches represented two distinct treatments: (1) a simplified reach, characterized by unstable fine substrate, clay, deeper channel and higher water velocity and (2) structurally complex reaches, characterized by coarse substrate, with gravel, pebble, rock, stems and branches and leaves inside the channel, producing a diverse pattern of microhabitat, associated with sequences of pools, runs, and riffles. Both trophic structure and taxonomic composition varied significantly between treatments. Invertivorous trophic group exclusively occurred in structurally complex reaches, which also presented greater diversity and species richness. We suggest enhancing in-stream environmental structure that suffered simplification processes due to human impacts in order to reestablish fish communities and ecossistemic functioning.

Status, Distribution, and Conservation of Native Freshwater Fishes of Western North America

ABSTRACT The Pacific lamprey <em>Lampetra tridentata</em> is a native Snake River basin fish species occupying a unique ecological niche. The recent decline in numbers of returning Pacific lamprey adults to the Snake River basin has focused attention on the species. In 2000–2002, we employed electrofishing surveys to determine habitat utilization and distribution of Pacific lamprey ammocoetes in Red River, South Fork Clearwater River drainage, Idaho. Ammocoete average densities were 25.7/100 m² in scour pools, 4.4/100 m² in riffles, 2.1/100 m² in rapids, and 253.3/100 m² in the one alcove sampled. Ammocoetes were found in water depths ranging from 1.0 cm to 1.0 m; however, the two greatest densities were observed in habitat units with maximum depths greater than 0.50 m. Pacific lamprey ammocoete density decreased with increased velocity and coarse substrate, and increased with fine and medium substrates and riparian shade.

The design and performance of a vertical flow reed bed for the treatment of high ammonia, low suspended solids organic effluents

A design approach for vertical flow constructed wetlands based on selection of not only bed size, but also substrate characteristics, configuration, plant species/variety and management is piloted in a trial system to treat sugar beet processing wastes. In the beet processing season these wastes are hot, low in suspended solids and relatively high in ammoniacal nitrogen. The pilot system consists of a small, coarse substrate first stage followed by a larger, fine substrate second stage. Results in the beet processing season show 87.3% COD removal, 87.7% TSS removal and a 79.5% reduction in ammoniacal nitrogen. Treating larger volumes of cooler stored wastes out of season, the mean removal efficiencies were 73.9% for COD, 88.0% for TSS and 93.4% for ammoniacal nitrogen. TSS removal m−2 was found to be independent of influent concentration and temperature, whilst COD removal m−2 was found to be independent of temperature, but not influent concentration. Removal of ammoniacal nitrogen appeared to be dependent upon influent concentration and, in particular, upon temperature. Infiltration rates were shown to be negatively correlated to length of dosing cycle. Simple models of substrate permeability based on substrate particle size distribution are seen to be inadequate for describing infiltration rates in vertical downflow systems, even those treating low strength wastes.