Detritivore Diversity or Dominant Species: What Drives Detrital Processing?

The role that biodiversity plays in maintaining ecosystem functioning has been debated for nearly two decades. Previous research suggested that a dominant species (Pycnopsyche gentilis) and not detritivore diversity determined leaf breakdown in a southern Appalachian stream. However, these previous studies could not directly compare the effects of other large detritivores (Tallaperla and Tipula) to that of Pycnopsyche. Here I report the results of a field experiment where I created monocultures, 2- and 3-species combinations of these three species and examined their effect on leaf breakdown. This experimental design allowed me to determine if these other taxa altered the effect of Pycnopsyche. Treatments containing Pycnopsyche exhibited the highest levels of leaf breakdown. Leaf mass lost (LML) in the 3-species polyculture was not significantly different from the Pycnopsyche monoculture. LML in the Tallaperla monocultures was indistinguishable from microbial breakdown. Tipula monocultures had intermediate LML. Neither Tallaperla nor Tipula facilitated or inhibited Pycnopsyche. However, when present together, Tallaperla inhibited breakdown by Tipula. My results confirm that Pycnopsyche is the functionally dominant detritivore in this system and suggest a novel mechanism that can influence diversity-function relationships. Inhibitory interactions among functionally subordinate species may result in reduced ecosystem function despite increases in species richness

Ground Improvement for Increasing Lateral Pile Group Resistance

Lateral load tests were performed on a full-scale pile cap in untreated clay along with pile groups involving (a) excavation and replacement with sand backfill, (b) a soilcrete wall along the side of the pile group, and (c) a jet grouted zone below the pile cap. The average compressive strength of the soft, plastic clay increased from an average of 50 kPa to an average of about 1000 kPa with soil mixing (10% cement) and to 3000 kPa with jet grouting (20% cement). Excavation and replacement only increased resistance by about 20%; however, the soil mixed wall increased resistance by 60%, and jet grouting increased resistance by 160%. For the soil mixed wall, essentially all of the increased resistance can be explained due to passive pressure and side/base shear against the soil mixed wall. However, for the jet grout treatment, additional resistance can also be attributed to increased structural resistance of the composite soilcrete volume under the cap. Soil mixing and jet grouting provide a means to significantly increase the lateral resistance of existing pile group foundations with relatively little investment of time, effort, and expense relative to the addition of more piles

Coyote Diets on the Rolling Plains Quail Research Ranch, Texas

Predation is a major cause of mortality and nest failure for the northern bobwhite (Colinus virginianus) across its range. Coyotes (Canis latrans) are a potential predator of bobwhites and typically the most common mesocarnivore on bobwhite range in Texas. Few data exist regarding the importance of bobwhites in the coyote’s diet in the Rolling Plains of Texas. We describe the seasonal and annual diets of coyotes on the Rolling Plains Quail Research Ranch (RPQRR), Fisher County, Texas. The RPQRR encompasses 1,902 ha of rolling terrain consisting of ridges and mesquite (Prosopis glandulosa) dominated rangeland; other common shrubs include netleaf hackberry (Celtis laevigata), littleleaf sumac (Rhus microphylla), lotebush (Ziziphus obtusifolia), wolfberry (Lycium berlandieri), chittam (Bumrlia lanuginosa), catclaws (Acacia spp., Mimosa spp.), and agarito (Mahonia trifoliolata). Prickly pear (Opuntia spp.) is abundant on most sites. The study area received 58 and 64 cm of rainfall, respectively during 2009 and 2010, below the 30-year average of 76 cm for Fisher County, Texas. We collected, and examined 720 coyote scats from December 2008 to December 2010. Each scat was prepared for analysis by placing it inside a nylon mesh bag and washing it for 2 cycles in an automatic washing machine. We analyzed scat contents macroscopically and any guard hairs were analyzed microscopically to identify prey to genus. We also collected estimates of abundance for a range of potential food sources including bobwhites, small mammals, and insects. Preliminary analyses suggest coyotes were minor predators of quail and their diets mainly consisted of seasonally-available mast (e.g., tunas of prickly pear) and rodents. Variation in timing and amount of rainfall during our study allowed us to document how coyotes adjusted their diets to the resulting fluctuations in food availability (especially mast)

Murine Model of Hindlimb Ischemia

In the United States, peripheral arterial disease (PAD) affects about 10 million individuals, and is also prevalent worldwide. Medical therapies for symptomatic relief are limited. Surgical or endovascular interventions are useful for some individuals, but long-term results are often disappointing. As a result, there is a need for developing new therapies to treat PAD. The murine hindlimb ischemia preparation is a model of PAD, and is useful for testing new therapies. When compared to other models of tissue ischemia such as coronary or cerebral artery ligation, femoral artery ligation provides for a simpler model of ischemic tissue. Other advantages of this model are the ease of access to the femoral artery and low mortality rate

Advantages of the no-scalpel vasectomy technique

The no-scalpel vasectomy (NSV) technique should be used instead of the standard incisional method. (Strength of Recommendation: A, based on systematic reviews, mixed-quality randomized controlled trials [RCTs], cohort studies, and case-control series.) The NSV technique is associated with fewer complications, produces less perioperative and postoperative pain, results in quicker recovery, takes less time to perform, and is as effective as standard incisional vasectomy

Translocation as a Population Restoration Technique for Northern Bobwhites: A Review and Synthesis

Northern bobwhite (Colinus virginianus) abundance has declined precipitously for decades across much of the species range, to the point of widespread local, regional, and statewide extirpation. Because of successful translocations of other gallinaceous birds, bobwhite enthusiasts increasingly call for use of the approach. Consequently, the National Bobwhite Technical Committee (NBTC), on behalf of state agencies, requested a review and recommendation by the NBTC Science Subcommittee. Thus, our paper is co-authored by invited experts and includes reviews of peer-reviewed publications, manuscripts in these proceedings, state agency reports, experience by co-authors, and a survey of perspectives on translocations by state wildlife agency members of the NBTC. We discuss the state of science on key aspects of bobwhite conservation, offer best management practices (BMPs) for using translocation as a potential bobwhite restoration technique, and suggest ways to reduce uncertainty about implementation. We note that although conservationists operate on a relatively solid foundation of improving bobwhite abundance via increased quantity, connectivity, and quality of habitat, population restoration success to- date is relatively rare and unpredictable. Similarly, some past translocations have been unreliable with an abundance of failures and inadequate experimental designs. We conclude that because of major uncertainties regarding habitat, population phenomena (e.g., Allee effect) and restoration techniques, outcomes of translocations remain unpredictable; thus, future efforts must be a part of sound and rigorous peer-reviewed research. To improve scientific efforts, we recommend the following BMPs for future translocations: (1) target bobwhite abundance should be \u3e800 post-translocation which will likely necessitate ≥600 ha of suitable and accessible habitat while a larger (e.g., \u3e800 ha) area will be needed in areas with lower carrying capacity and when sites are highly fragmented or isolated, (2) personnel should identify and avoid stressors to bobwhites in all phases of the translocation process (i.e., capture, holding, transportation, and release), (3) source populations should be disease free and from similar environments and latitude; preferably from the nearest suitable source, (4) conspecifics should be present on recipient sites (5) birds should be released just before the breeding season (i.e., March or April), and (6) the translocation should incorporate robust short- and long-term bird (i.e., abundance and/or density) and habitat monitoring efforts (i.e., the Coordinated Implementation Program (CIP) of the National Bobwhite Conservation Initiative (NBCI)). In conclusion, we note that translocation of bobwhites is not a panacea for broad scale restoration of bobwhites; however, the technique should remain at the forefront of bobwhite science, taking into account knowledge of the species’ life history and ecology, so that a practical and reliable solution can be developed. We recognize this paper is just the beginning of vigorous debate, testing of concepts, and on-the ground implementation of successful bobwhite conservation

The complete genome sequence of the phytopathogenic fungus Sclerotinia sclerotiorum reveals insights into the genome architecture of broad host range pathogens

Sclerotinia sclerotiorum is a phytopathogenic fungus with over 400 hosts including numerous economically important cultivated species. This contrasts many economically destructive pathogens that only exhibit a single or very few hosts. Many plant pathogens exhibit a “two-speed” genome. So described because their genomes contain alternating gene rich, repeat sparse and gene poor, repeat-rich regions. In fungi, the repeat-rich regions may be subjected to a process termed repeat-induced point mutation (RIP). Both repeat activity and RIP are thought to play a significant role in evolution of secreted virulence proteins, termed effectors. We present a complete genome sequence of S. sclerotiorum generated using Single Molecule Real-Time Sequencing technology with highly accurate annotations produced using an extensive RNA sequencing data set. We identified 70 effector candidates and have highlighted their in planta expression profiles. Furthermore, we characterized the genome architecture of S. sclerotiorum in comparison to plant pathogens that exhibit “two-speed” genomes. We show that there is a significant association between positions of secreted proteins and regions with a high RIP index in S. sclerotiorum but we did not detect a correlation between secreted protein proportion and GC content. Neither did we detect a negative correlation between CDS content and secreted protein proportion across the S. sclerotiorum genome. We conclude that S. sclerotiorum exhibits subtle signatures of enhanced mutation of secreted proteins in specific genomic compartments as a result of transposition and RIP activity. However, these signatures are not observable at the whole-genome scale