Debris Manipulations Research Articles

Space Debris Manipulation by Cooperative Redundant Planar Robots with Minimized Trajectory Error

Space Debris Manipulation by Cooperative Redundant Planar Robots with Minimized Trajectory Error

Rodent population and community responses to experimental, large scale, long-term coarse woody debris manipulations

Coarse woody debris (CWD) is a structural feature in forests throughout the United States that provides unique cover, runways, and microclimate for various wildlife species. While use and selection of CWD for rodent foraging, travel, and nesting, which can impact an individual’s fitness, has been demonstrated across numerous studies, the role of CWD presence and abundance in rodent population and community dynamics varies across studies. To better understand rodent and CWD relationships, we studied rodent populations across two periods of CWD manipulation in randomly assigned experimental treatments in South Carolina (Period I: March 1996–November 2000; removal of all snags and fallen logs, removal of fallen logs only, and Control, and Period II: January 2002–September 2006; downed woody debris addition, snag addition, and Control). Overall, we found minimal effects of experimental treatments on the rodent community composition and structure, and community level variation was mainly explained by cotton mouse (Peromyscus gossypinus) and southern flying squirrel (Glaucomys volans) captures. There were no experimental treatment effects on captures of cotton mice and southern flying squirrels, but we observed variation across seasons and years. Our study shows that over the long-term, rodent population and community dynamics are not affected by experimental manipulations of CWD in our study area.

Asteroid and Space Debris Manipulation: Advances from the Stardust Research Network. Progress in Aeronautics and Astronautics Vol. 250 Edited by M. Vasile and E. Minisci American Institute of Aeronautics and Astronautics, Reston, VA. 2016. 516pp. Illustrated. Distributed by Transatlantic Publishers Group, 97 Greenham Road London N10 1LN, UK. 948pp. Illustrated £108. (20% discount available to RAeS members on request; e-mail:

Asteroid and Space Debris Manipulation: Advances from the Stardust Research Network. Progress in Aeronautics and Astronautics Vol. 250Edited by M. Vasile and E. Minisci American Institute of Aeronautics and Astronautics, Reston, VA. 2016. 516pp. Illustrated. Distributed by Transatlantic Publishers Group, 97 Greenham Road London N10 1LN, UK. 948pp. Illustrated £108. (20% discount available to RAeS members on request; e-mail: mark.chaloner@tpgltd.co.uk Tel:- 020-8815 5994) ISBN 978-1-62410-323-0. - Volume 123 Issue 1266

Disentangling the long-term effects of disturbance on soil biogeochemistry in a wet tropical forest ecosystem.

Climate change is increasing the intensity of severe tropical storms and cyclones (also referred to as hurricanes or typhoons), with major implications for tropical forest structure and function. These changes in disturbance regime are likely to play an important role in regulating ecosystem carbon (C) and nutrient dynamics in tropical and subtropical forests. Canopy opening and debris deposition resulting from severe storms have complex and interacting effects on ecosystem biogeochemistry. Disentangling these complex effects will be critical to better understand the long-term implications of climate change on ecosystem C and nutrient dynamics. In this study, we used a well-replicated, long-term (10years) canopy and debris manipulation experiment in a wet tropical forest to determine the separate and combined effects of canopy opening and debris deposition on soil C and nutrients throughout the soil profile (1m). Debris deposition alone resulted in higher soil C and N concentrations, both at the surface (0-10cm) and at depth (50-80cm). Concentrations of NaOH-organic P also increased significantly in the debris deposition only treatment (20-90cm depth), as did NaOH-total P (20-50cm depth). Canopy opening, both with and without debris deposition, significantly increased NaOH-inorganic P concentrations from 70 to 90cm depth. Soil iron concentrations were a strong predictor of both C and P patterns throughout the soil profile. Our results demonstrate that both surface- and subsoils have the potential to significantly increase C and nutrient storage a decade after the sudden deposition of disturbance-related organic debris. Our results also show that these effects may be partially offset by rapid decomposition and decreases in litterfall associated with canopy opening. The significant effects of debris deposition on soil C and nutrient concentrations at depth (>50cm), suggest that deep soils are more dynamic than previously believed, and can serve as sinks of C and nutrients derived from disturbance-induced pulses of organic matter inputs.

Soil Temperature following Logging-Debris Manipulation and Aspen Regrowth in Minnesota: Implications for Sampling Depth and Alteration of Soil Processes

Soil temperature is a fundamental controller of processes influencing the transformation and flux of soil C and nutrients following forest harvest. Soil temperature response to harvesting is influenced by the amount of logging debris (biomass) removal that occurs, but the duration, magnitude, and depth of influence is unclear. Logging debris manipulations (none, moderate, and heavy amounts) were applied following clearcut harvesting at four aspen-dominated (Populus tremuloides Michx.) sites in northeastern Minnesota, and temperature was measured at 10-, 30-, and 50-cm depths for two growing seasons. Across sites, soil temperature was significantly greater at all sample depths relative to uncut forest in some periods of each year, but the increase was reduced with increasing logging-debris retention. When logging debris was removed compared to when it was retained in the first growing season, mean growing season soil temperatures were 0.9, 1.0, and 0.8°C greater at 10-, 30-, and 50-cm depths, respectively. These patterns were also observed early in the second growing season, but there was no discernible difference among treatments later in the growing season due to the modifying effect of rapid aspen regrowth. Where vegetation establishment and growth occurs quickly, effects of logging debris removal on soil temperature and the processes influenced by it will likely be short-lived. The significant increase in soil temperature that occurred in deep soil for at least 2 yr after harvest supports an argument for deeper soil sampling than commonly occurs in experimental studies.

Debris manipulation alters soil CO2 efflux in a subtropical plantation forest

Potential changes in the quality and quantity of C inputs in soil during environmental changes may affect soil CO2 efflux in forest ecosystems. Therefore, a field debris exclusion experiment and a laboratory debris addition experiment were conducted to assess the response of soil CO2 efflux to C input manipulation. Our experiments were the first to be conducted in a subtropical Chinese fir (Cunninghamia lanceolata) plantation. The field debris exclusion experiment included the following treatments: leaf litter exclusion (NL), leaf litter and root exclusion (NLR), and control (CT). In the laboratory experiment, leaf litter and fine and coarse roots were added to soils collected from the same site and incubated for 100days at 15.0°C using the isotopic partitioning approach to determine the priming effect on soil C. The field-experimental results showed that soil CO2 efflux decreased significantly by 22.9% and 49.1% in the NL and NLR plots, respectively, compared with the CT plots. However, debris exclusion did not affect the diurnal and seasonal patterns of soil CO2 efflux. The contributions of leaf litter and roots to total soil CO2 efflux were 22.9% and 26.2%, respectively, which were positively related to soil temperature and moisture. In the laboratory experiment, the cumulative amount of soil CO2 efflux increased 1.25, 0.51, and 0.43 times in the soils with leaf litter, fine root, and coarse root additions, respectively, compared with the control soil (without debris addition) at the end of the incubation period. The amount of CO2 derived from leaf litter, fine root, and coarse root additions accounted for 44.0%, 31.1%, and 27.9% of the total amount of soil CO2 efflux, respectively. During the experimental period, the priming effect induced by fast-decomposing leaf litter (25.9%) was significantly higher than the priming effect induced by slow-decomposing fine roots (3.8%) and coarse roots (2.9%). The priming effect was negatively correlated with the initial lignin content and the lignin:N ratios of the added debris. The similar contributions of leaf litter and roots to soil CO2 efflux from the field experiment and the greater contributions of the priming of leaf litters to the fluxes from the laboratory experiment suggest that root inputs are more important than litter inputs in regulating soil C storage in Chinese fir forests.

Effects of logging debris treatments on five-year development of competing vegetation and planted Douglas-fir

Although considerable research has focused on the influences of logging debris treatments on soil and forest regeneration responses, few studies have identified whether debris effects are mediated by associated changes in competing vegetation abundance. At sites near Matlock, Washington, and Molalla, Oregon, studies were initiated after timber harvest to quantify the effects of three logging debris treatments (dispersed, piled, or removed) on the development of competing vegetation and planted Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco var. menziesii ). Each debris treatment was replicated with initial and annual vegetation control treatments, resulting in high and low vegetation abundances, respectively. This experimental design enabled debris effects on regeneration to be separated into effects mediated by vegetation abundance and those independent of vegetation abundance. Two to three years after treatment, covers of Scotch broom ( Cytisus scoparius (L.) Link) at Matlock and trailing blackberry ( Rubus ursinus Cham. & Schltdl.) at Molalla were over 20% greater where debris was piled than where it was dispersed. Debris effects on vegetation abundance were associated with 30% reductions in the survival of Douglas-fir at Matlock (r2 = 0.62) and the stem diameter at Molalla (r2 = 0.39). Douglas-fir survival and growth did not differ among debris treatments when effects were evaluated independent of vegetation abundance (i.e., with annual vegetation control), suggesting negligible short-term effects of debris manipulation on soil productivity.

Amphibian and reptile community response to coarse woody debris manipulations in upland loblolly pine ( Pinus taeda) forests

Coarse woody debris (CWD) has been identified as a key microhabitat component for groups that are moisture and temperature sensitive such as amphibians and reptiles. However, few experimental manipulations have quantitatively assessed amphibian and reptile response to varying CWD volumes within forested environments. We assessed amphibian and reptile response to large-scale, CWD manipulation within managed loblolly pine stands in the southeastern Coastal Plain of the United States from 1998 to 2005. Our study consisted of two treatment phases: Phase I treatments included downed CWD removal (removal of all downed CWD), all CWD removal (removal of all downed and standing CWD), pre-treatment snag, and control; Phase II treatments included downed CWD addition (downed CWD volume increased 5-fold), snag addition (standing CWD volume increased 10-fold), all CWD removal (all CWD removed), and control. Amphibian and anuran capture rates were greater in control than all CWD removal plots during study Phase I. In Phase II, reptile diversity and richness were greater in downed CWD addition and all CWD removal than snag addition treatments. Capture rate of Rana sphenocephala was greater in all CWD removal treatment than downed CWD addition treatment. The dominant amphibian and snake species captured are adapted to burrowing in sandy soil or taking refuge under leaf litter. Amphibian and reptile species endemic to upland southeastern Coastal Plain pine forests may not have evolved to rely on CWD because the humid climate and short fire return interval have resulted in historically low volumes of CWD.

Soricid response to coarse woody debris manipulations in Coastal Plain loblolly pine forests

We assessed shrew (soricids) response to coarse woody debris (CWD) manipulations in managed upland loblolly pine ( Pinus taeda) stands in the upper Coastal Plain of South Carolina over multiple years and seasons. Using a completely randomized block design, we assigned one of the following treatments to 12, 9.3-ha plots: removal ( n = 3; all CWD ≥ 10 cm in diameter and ≥60 cm long removed), downed ( n = 3; 5-fold increase in volume of down CWD), snag ( n = 3; 12-fold increase in standing dead CWD), and control ( n = 3; unmanipulated). Therein, we sampled shrews during winter, spring, and summer seasons, 2003–2005, using drift-fence pitfall arrays. During 1680 drift-fence plot nights we captured 253 Blarina carolinensis, 154 Sorex longirostris, and 51 Cryptotis parva. Blarina carolinensis capture rate was greater in control than in snag treatments. Sorex longirostris capture rate was lower in removal than downed and control plots in 2005 whereas C. parva capture rate did not differ among treatments. Overall, the CWD input treatments failed to elicit the positive soricid response we had expected. Lack of a positive response by soricid populations to our downed treatments may be attributable to the early CWD decay stage within these plots or an indication that within fire-adapted pine-dominated systems of the Southeast, reliance on CWD is less than in other forest types.

Experimental provision of large woody debris in streams as a trout management technique

Abstract The natural stock of large woody debris (LWD) in the afforested Douglas River (Fermoy, Co. Cork) is very low relative to old‐growth forests, which seems to arise from deficiency both of supply and retention. Woody debris is important to the ecology and physical structure of forest streams, so its abundance is relevant to aquatic conservation and the maintenance and size of salmonid fish stocks. The physical characteristics and fish stocks of 16 contiguous segments of two 200 m stream reaches were surveyed in spring 1998 prior to the installation of 12 partially spanning debris structures on four of the segments. This study investigated the effect of debris structures on the heterogeneity of flow and substratum, and the distribution of brown trout (Salmo trutta), and assessed the potential use of woody debris manipulation as a tool in the management of forest streams. Surveys of stream habitat conditions over a 2 year period following the installation of woody debris showed a change in stream architecture. This created more suitable habitat for trout through development of additional pools in which beds of fine sediment developed, and constraining the main current, increasing the amount of eddies and slack water areas. There were significant increases in trout density and biomass in the debris segments relative to control segments without debris dams 1 and 2 years after debris addition, although trout condition was not modified by the addition of LWD. These results suggest that the addition of woody debris offers a positive and practical management technique for enhancing fish in plantation forest streams. Copyright © 2002 John Wiley & Sons, Ltd.

Habitat selection by juvenile coho salmon in response to food and woody debris manipulations in suburban and rural stream sections

This study explored the effects of food and woody debris manipulations on the summer distribution of juvenile coho salmon (Oncorhynchus kisutch) in small suburban streams. To examine fish responses to these factors, three different experiments were carried out in modified sections of two streams. The results showed that the distribution of juvenile coho salmon in a stream section was primarily controlled by the availability and distribution of food among pools and by the presence and density of woody debris. Food, however, played a dominant role because the foraging quality of a pool not only affected the density of fish in it but also the response of those fish towards instream debris. In food-rich stream sections, low proportions of juvenile coho salmon occupied pools with dense woody debris in the spring, which changed towards late summer. In contrast, in food-poor reaches, high proportions of fish were found in pools with abundant debris in the spring. Pools that combined abundant food with sparse woody debris were the most favoured by the fish. It is important that salmonid habitat enhancement projects consider that open foraging areas interspersed with woody debris characterize the type of summer habitat that juvenile coho salmon prefer.

Habitat selection by juvenile coho salmon in response to food and woody debris manipulations in suburban and rural stream sections

This study explored the effects of food and woody debris manipulations on the summer distribution of juvenile coho salmon (Oncorhynchus kisutch) in small suburban streams. To examine fish responses to these factors, three different experiments were carried out in modified sections of two streams. The results showed that the distribution of juvenile coho salmon in a stream section was primarily controlled by the availability and distribution of food among pools and by the presence and density of woody debris. Food, however, played a dominant role because the foraging quality of a pool not only affected the density of fish in it but also the response of those fish towards instream debris. In food-rich stream sections, low proportions of juvenile coho salmon occupied pools with dense woody debris in the spring, which changed towards late summer. In contrast, in food-poor reaches, high proportions of fish were found in pools with abundant debris in the spring. Pools that combined abundant food with sparse woo...