Studying organic matter molecular assemblage within a whole organic soil by nuclear magnetic resonance

This work shows the applicability of two-dimensional (2D) (1)H-(13)C heteronuclear correlation (HETCOR) nuclear magnetic resonance (NMR) spectroscopy to the characterization of whole soils. A combination of different mixing times and cross polarization (CP) methods, namely Lee-Goldberg (LG)-CP and Ramp-CP are shown to afford, for the first time, intra- and inter- molecular connectivities, allowing for molecular assemblage information to be obtained on a whole soil. Our results show that, for the brackish marsh histosol under study, two isolated domains could be detected. The first domain consists of O-alkyl and aromatic moieties (lignocellulose material), while the second domain is comprised of alkyl type moieties (cuticular material). The role of these domains is discussed in terms of hydrophobic organic compound sorption within soil organic matter (SOM), including the possible effects of wetting and drying cycles.     

Delineating protected wildlife corridors with multi‐objective programming

Protected wildlife corridors can help counteract habitat fragmentation and link isolated reserve “islands” into connected reserve systems. The need for wildlife corridors will grow as expanding human populations place increasing pressure on remaining undeveloped land. A two‐objective zero–one programming model is formulated for the problem of selecting land for a system of wildlife corridors that must connect a known set of existing reserves or critical habitat areas. This problem is modeled as a network Steiner tree problem, under the objectives of minimizing corridor land costs and minimizing the amount of unsuitable land within the corridor system. Linear programming is used to find exact solutions with little or no branching and bounding, and the multi‐objective weighting method is used to generate non‐inferior alternatives. Two hypothetical examples demonstrate the model and solution procedure. Results can help inform planning and decision making for protected area land acquisition and habitat restoration.     

Pilot see,pilot do: Examining the predictors of pilots’ risk management behaviour

Decision-making under uncertainty, known as risk management, is common in many professions including medicine and the military. Within general aviation, it is a skill that pilots are largely expected to acquire through experience. This study sought to determine if there are known markers (i.e., attitude and risk perception) and or personal characteristics (i.e., flight experience and age) that predict the acquisition and utilization of this skill. Fifty-six participants were presented with a risky flight which involved searching for a wayward parachutist with minimal fuel on board their aircraft. A clear distinction in terms of ‘risk perception’ was evident between those pilots who elected to undertake the risky flight (36 participants) and those pilots who did not (20 participants). There was also evidence of attitudinal and demographic differences between the two groups. The results have implications for the selection and training of pilots.     

Perceptions of Species Abundance,Distribution, and Diversity: Lessons from Four Decades of Sampling on a Government-Managed Reserve

/ We examined data relative to species abundance, distribution, anddiversity patterns of reptiles and amphibians to determine how perceptionschange over time and with level of sampling effort. Location data werecompiled on more than one million individual captures or observations of 98species during a 44-year study period on the US Department of Energy's(DOE) Savannah River Site National Environmental Research Park (SRS-NERP) inSouth Carolina. We suggest that perceptions of herpetofaunal speciesdiversity are strongly dependent on level of effort and that land managementdecisions based on short-term data bases for some faunal groups could resultin serious errors in environmental management. We provide evidence thatacquiring information on biodiversity distribution patterns is compatiblewith multiyear spatially extensive research programs and also provide aperspective of what might be achieved if long-term, coordinated researchefforts were instituted nationwide.To conduct biotic surveys on government-managed lands, we recommend revisionsin the methods used by government agencies to acquire and report biodiversitydata. We suggest that government and industry employees engaged inbiodiversity survey efforts develop proficiency in field identification forone or more major taxonomic groups and be encouraged to measure the status ofpopulations quantitatively with consistent and reliable methodologies. Wealso suggest that widespread academic cooperation in the dissemination ofinformation on regional patterns of biodiversity could result byestablishment of a peer-reviewed, scientifically rigorous journal concernedwith status and trends of the biota of the United States. KEY WORDS: Abundance; Amphibian; Biodiversity; Distribution; Landmanagement; Reptile     

Introduction to the Special Issue

Introduction

Introduction to the Special Issue     

Applying DPSIR to sustainable development

The DPSIR framework was devised in the late 1990s as a tool for the reporting and analysis of environmental problems, ranging in scale from global systems to localized watersheds. Since then, international organizations have begun to apply this framework to the evaluation of sustainable development initiatives, to better understand and overcome barriers to sustainability. While this may seem a logical application for an integrated environmental assessment tool, the use of DPSIR in sustainable development will likely perpetuate the least satisfactory outcomes of development. DPSIR cannot address the impact of aggregated, informal responses on the drivers and pressures related to environmental problems and sustainability challenges. This problem is not merely an oversight of the framework, but an issue that emerges within the structure of DPSIR itself through the unexamined, unacknowledged hierarchy of actors that this framework implicitly creates with its typology. Therefore, a DPSIR-centered approach is not a new direction for development within international organizations, but instead, a reproduction of existing inequalities between actors and stakeholders within current approaches.     

Spatio-temporal vigilance architecture of an Australian flying-fox colony

The social structure of animal aggregations may vary considerably in both space and time, yet little is known about how this affects vigilance. Here, we investigate the vigilance architecture of a colony of wild-living grey-headed flying-foxes (Pteropus poliocephalus) in Australia and examine how spatial as well as temporal variation in social organization influences social and environmental vigilance. We sampled color-marked individuals at different stages of the reproductive cycle and the year and at different locations in the colony to examine the effects of temporal and spatial factors on social and environmental vigilance. We found that vigilance architecture reflected the social structure of the colony, with the highest environmental vigilance being displayed by bats at the periphery of the colony, and the highest social vigilance by bats that roosted at intermediate distances from the colony’s edge. Furthermore, we found that vigilance levels reflected changes in reproductive state, with social vigilance increasing toward the mating season, particularly in males. Our findings show that spatial and temporal variation in social structure can have differential effects on social and environmental vigilance. This highlights the necessity to differentiate between functions of vigilance to understand fully vigilance architecture in aggregations of social animals.     

What can we learn from resource pulses?

An increasing number of studies in a wide range of natural systems have investigated how pulses of resource availability influence ecological processes at individual, population, and community levels. Taken together, these studies suggest that some common processes may underlie pulsed resource dynamics in a wide diversity of systems. Developing a common framework of terms and concepts for the study of resource pulses may facilitate greater synthesis among these apparently disparate systems. Here, we propose a general definition of the resource pulse concept, outline some common patterns in the causes and consequences of resource pulses, and suggest a few key questions for future investigations. We define resource pulses as episodes of increased resource availability in space and time that combine low frequency (rarity), large magnitude (intensity), and short duration (brevity), and emphasize the importance of considering resource pulses at spatial and temporal scales relevant to specific resource-onsumer interactions. Although resource pulses are uncommon events for consumers in specific systems, our review of the existing literature suggests that pulsed resource dynamics are actually widespread phenomena in nature. Resource pulses often result from climatic and environmental factors, processes of spatiotemporal accumulation and release, outbreak population dynamics, or a combination of these factors. These events can affect life history traits and behavior at the level of individual consumers, numerical responses at the population level, and indirect effects at the community level. Consumers show strategies for utilizing ephemeral resources opportunistically, reducing resource variability by averaging over larger spatial scales, and tolerating extended interpulse periods of reduced resource availability. Resource pulses can also create persistent effects in communities through several mechanisms. We suggest that the study of resource pulses provides opportunities to understand the dynamics of many specific systems, and may also contribute to broader ecological questions at individual, population, and community levels.     

Biotic control of stream fluxes: spawning salmon drive nutrient and matter export

Organisms can control movements of nutrients and matter by physically modifying habitat. We examined how an ecosystem engineer, sockeye salmon (Oncorhynchus nerka), influences seasonal fluxes of sediments, nitrogen (N), and phosphorus (P) in streams of southwestern Alaska. The purpose of this study was to investigate whether salmon act as net importers or net exporters of matter and nutrients from streams and how these roles change as a function of salmon population density. We measured discharge and concentrations of suspended sediments and total N and P every 7-14 days for up to four summers in 10 streams spanning a gradient in salmon densities. We statistically allocated whole-season fluxes to salmon activities, such as excretion and bioturbation, and to export by hydrologic discharge. In addition, we used counts of spawning salmon to estimate nutrient and matter imports by salmon to streams. Large seasonal pulses of suspended sediments, P, and N were associated with salmon spawning activities, often increasing export an order of magnitude higher than during pre-salmon levels. Years and streams with more salmon had significantly higher levels of export of sediments and nutrients. In addition, years with higher precipitation had higher background export of P and N. Salmon exported an average of the equivalent of 189%, 60%, and 55% of total matter, P, and N that salmon imported in their bodies. The relative magnitude of export varied; salmon exported more than their bodies imported in 80%, 20%, and 16% across all streams and years for sediments, P, and N, respectively. A bioassay experiment indicated that the P exported by salmon is directly available for use by primary producers in the downstream lake. These results demonstrate that salmon not only move nutrients upstream on large spatial scales via their migration from the ocean and subsequent death, but also redistribute matter and nutrients on finer spatial scales through their spawning activities.