Group selection harvesting supports diversity of forest specialist carabids

Increased fragmentation and considerable environmental changes in native forests caused by the timber-oriented forest managements are threatening the biodiversity of forests. As a remediation, uneven-aged approach is recommended during forest management, because this is less intensive and could be less harmful than even-aged practices. We tested the effects of clear-cutting (as even-aged method) and group selection harvesting (as uneven-aged method) on carabids in lowland oak forests. Pitfall traps and litter sifting were used during the study. We found that the total number of species was significantly higher in the gaps harvested by group selection and in the clear-cut than in the mature forests (control area). The species richness of forest specialist species was significantly lower in the clear-cuts than in the other area. Our findings demonstrated that the conventional clear-cutting caused a decrease in the number of forest specialist species. Therefore, group selection method should be favoured during forest management to maintain diversity.

Resident and cavity-nesting avian community is affected by amount but not age of white pine in central Ontario mature mixedwood forests

Forests with old-growth white pines have been severely reduced compared with historical levels. We examined resident and cavity-nesting bird species abundances in winter and the breeding season, because some of these species may prefer old-forest habitats for breeding. We counted birds over 10 years in four mixedwood types: old pine, mature pine, mature nonpine, and selection-harvested stands. We expected that old pine stands would be selected by some species because of abundant snags and large trees for foraging. We assessed habitat use among years and changes following harvesting. Counts of nomadic species varied across years but counts for others did not. Species used old and mature pine mixedwoods equally and more than nonpine or harvested stands in winter and for breeding, but old stands were not preferred. Important variables included percent pine and large tree density. Selection harvesting benefitted Yellow-bellied Sapsuckers but reduced counts of Black-capped Chickadees and Brown Creepers. Black-capped Chickadees changed habitats between seasons and in some years. Black-backed Woodpeckers were most common in pine stands but abundant in harvested stands for 2 years following cutting. Regardless of stand age, large (>40 cm) pines provide important habitat for residents and cavity nesters.

The RodBot approach to automated crystal harvesting

Automated crystal harvesting is the main gap in the otherwise highly automated process of structure determination by X-ray crystallography. Many approaches have been presented, but few have proceeded beyond the initial, developmental stage. We recently introduced a rod-shaped microrobot1 (the "RodBot") to assist in the harvesting process. Driven by rotating magnetic fields to roll on a substrate, RodBots induce fluid flows that can lift crystals off the surface and trap them in a cylindrical vortex that travels with the RodBot. The gentle, fluidic force acting on the crystals is in the range of a few nanoNewtons to tens of nanoNewtons, and is spread over the whole surface of the crystal. Forces of this magnitude enable the RodBot to safely manipulate crystals ranging from a few microns to sub-millimeter size. With this technique individual crystals can be selected and brought to a loop positioned in the growth droplet to accept it. Harvesting and flash-cooling is then possible using a simple mechanical linkage. In this way the whole operation of crystal selection, harvesting and flash-cooling is remotely and gently carried out without the operator jitter or application of excessive strain that lead to high late-stage failure rates in crystal harvesting. Guidance is provided by the driving magnetic field, and can involve either manual input with a joystick or fully automated algorithms with feedback control. Because of this option of remote operation, RodBots can also be used for harvesting in hostile, sensitive or inconvenient environments such as anaerobic chambers, controlled humidity environments or cold rooms. The system is compatible with existing crystallization hardware and can be integrated readily into typical laboratory setups or high-throughput platforms.