Non-linear density dependence in time series is not evidence of non-logistic growth

Time series of population density are often used to seek deviations from logistic regulation by testing for a non-linear decline in per capita growth rate with density. Here I show that this method fails when the interval between observations is not matched by the timing of density impacts on growth. Time series overestimate instantaneous density impacts at low density and underestimate them at high density. More generally, logistic growth produces a deterministically decelerating decline in per capita growth with density if the interval between measures of population size exceeds any lag in density response. Deceleration arises independently out of stochastic density fluctuations, and under-compensating regulation. These multiple influences lead to the conclusion that sequential density estimates provide insufficient information on their own to reveal the identity of non-logistic growth processes. They can yield estimates of density compensation, however, which may suggest time lags in density dependence. Analysis of an empirical time series illustrates the issues

An agent-based model of jaguar movement through conservation corridors

Wildlife corridors mitigate against habitat fragmentation by connecting otherwise isolated regions, bringing well established benefits to conservation both in principle and practice. Populations of large mammals in particular may depend on habitat connectivity, yet conservation managers struggle to optimise corridor designs with the rudimentary information generally available on movement behaviours. We present an agent-based model of jaguars (Panthera onca), scaled for fragmented habitat in Belize where proposals already exist for creating a jaguar corridor. We use a leastcost approach to simulate movement paths through alternative possible landscapes. Six different types of corridor and three control conditions differ substantially in their effectiveness at mixing agents across the environment despite relatively little difference in individual welfare. Our best estimates of jaguar movement behaviours suggest that a set of five narrow corridors may out-perform one wide corridor of the same overall area. We discuss the utility of ALife modelling for conservation management

Using virtual spaces for learning communities to facilitate project development and collaborative learning

With the extensive expansion of IT in the learning, business and home environments it is becoming apparent that there is considerable opportunity for increasing collaborative interaction if a framework is developed to coordinate the activities of the individuals across the different sectors. As a possible way of achieving this objective we present the online Community of Practice (CoP) developed and presently being trialled at the Institute for Work Based Learning (IWBL), Middlesex University. In this paper, we describe our approach for developing and utilising of this Community of Practice. Through case studies we will give two ways in which it is being currently applied. We will define what we have presently achieved and go on to outline future developments

Similar biodiversity of ectomycorrhizal fungi in set-aside plantations and ancient old-growth broadleaved forests

Setting aside overmature planted forests is currently seen as an option for preserving species associated with old-growth forests, such as those with dispersal limitation. Few data exist, however, on the utility of set-aside plantations for this purpose, or the value of this habitat type for biodiversity relative to old-growth semi-natural ecosystems. Here, we evaluate the contribution of forest type relative to habitat characteristics in determining species richness and composition in seven forest blocks, each containing an ancient old-growth stand (> 1000 yrs) paired with a set-aside even-aged planted stand (ca. 180 yrs). We investigated the functionally important yet relatively neglected ectomycorrhizal fungi (EMF), a group for which the importance of forest age has not been assessed in broadleaved forests. We found that forest type was not an important determinant of EMF species richness or composition, demonstrating that set-aside can be an effective option for conserving ancient EMF communities. Species richness of above-ground EMF fruiting bodies was principally related to the basal area of the stand (a correlate of canopy cover) and tree species diversity, whilst richness of below-ground ectomycorrhizae was driven only by tree diversity. Our results suggest that overmature planted forest stands, particularly those that are mixed-woods with high basal area, are an effective means to connect and expand ecological networks of ancient old-growth forests in historically deforested and fragmented landscapes for ectomycorrhizal fungi

How to Establish an SGA Open Education Award on Your Campus

In 2015, Texas A&M University (TAMU) Libraries and the TAMU Student Government Association (SGA) established the Open Educator Awards through student legislation. Dr. Bruce Herbert shared documentation via TAMU’s institutional repository to guide other universities in creating similar awards (1). In academic years 2017 and 2018, the SGA at University of Tennessee (UT) has recognized faculty and instructors who are leaders in adopting open educational resources (OERs), and open textbooks in particular, through the SGA Open Education Awards. Based on TAMU’s model, the awards include significant support from UT’s University Libraries throughout the process. Because workload and stakeholder expectations are difficult to gauge when beginning any new project, presenters will outline their experiences establishing the awards with the aim of helping other OER advocates determine whether such an outreach approach may be effective on their campuses. This poster will provide an overview of steps taken to create UT\u27s SGA Open Education Awards. The steps can be generally summarized as 1) establishing the awards, 2) organizing and coordinating efforts, 3) distributing awards, and 4) harnessing momentum generated by the awards. Additionally, the poster will include considerations in forecasting potential outcomes of the awards by listing partnerships and collaborations in campus OER advocacy that may occur after the awards become established on a campus. Accompanying the poster will be handouts (physical and digital) with more information about the process. Rather than presenting the steps in a traditional presentation, the poster format will allow others to read through this “recipe,” consider how it might be improved in their own kitchens, and discuss ideas freely with other cooks. With this outline, and documentation on SGA legislation from TAMU, OER advocates will have a practical handbook for developing a student-driven OER award for their campuses. (1) Bruce Herbert, “Texas A&M Student Government OER Teaching Awards,” Texas A&M OAKTrust Digital Repository, 2015, http://hdl.handle.net/1969.1/156092

Influence of oxygen uptake kinetics on physical performance in youth soccer

Purpose: To examine the relationship between oxygen uptake kinetics (VO2 kinetics) and physical measures associated with soccer match-play, within a group of highly trained youth soccer players. Methods: Seventeen highly trained youth soccer players (age: 13.3 ± 0.4 yr, self-assessed Tanner Stage: 3 ± 1) volunteered for the study. Players initially completed an incremental treadmill protocol to exhaustion, to establish gaseous exchange threshold (GET) and VO2max (59.1 ± 5.4 mL.kg-1.min-1). On subsequent visits players completed a step transition protocol from, rest–moderate intensity exercise, followed by an immediate transition from moderate–severe intensity exercise (moderate: 95%GET, severe: 60%∆), during which VO2 kinetics were determined. Physical soccer-based performance was assessed using a maximal Yo-Yo Intermittent Recovery test level 1 (Yo-Yo IR1) and via GPS derived measures of physical soccer performance during soccer match-play, 3 2 x 20min, 11 v 11 matches, to gain measures of physical performance during soccer match-play. Results: Partial correlations revealed significant inverse relationships between the unloaded to moderate transition time constant (tau) and: Yo-Yo IR1 performance (r = -0.58, P = 0.02) and GPS variables (Total distance (TD): r = - 0.64, P = 0.007, High speed running (HSR): r = - 0.64, P = 0.008, High speed running efforts (HSReff): r = - 0.66, P = 0.005). Conclusion: Measures of VO2 kinetics are related to physical measures associated with soccer match-play and could potentially be used to distinguish between those of superior physical performance, within a group of highly-trained youth soccer players