Three-dimensional assessment of movement patterns of Sichuan snub-nosed monkeys affected by habitat structure in temperate forests

DEAR EDITOR,Movement patterns can reflect species-specific characteristics of individuals and animal groups at a given scale. Accurate three-dimensional(3D) assessment can quantify the relationship between movement patterns of an animal and its unique habitat. Here, we evaluated the effects of habitat structure on movement patterns of the golden snub-nosed monkey(Rhinopithecus roxellana). We used airborne light detection and ranging(LiDAR) to map the 3D structure of the temperate forest in the Qinling Mountains(Shaanxi, China).

Antimicrobial Effectiveness on Selected Bacterial Species and Alkaloid and Saponin Content of <i>Rosa nutkana</i>C. Presl (Nootka Rose) and <i>Urtica dioica</i>L. (Stinging Nettle) Extracts

Nootka rose (Rosa nutkana C. Presl) and stinging nettle (Urtica dioica L.) have been traditionally used in the treatment of skin infection by Indigenous peoples of Vancouver Island, British Columbia, Canada. The main objective of this study was to examine the antibacterial efficacy of extracts of Nootka rose and stinging nettle against the common pathogenic skin bacteria Staphylococcus aureus, Micrococcus luteus, and Pseudomonas aeruginosa using Indigenous science and standard methods of analysis. The Indigenous science method of plant extraction by steeping as advised by the Traditional Knowledge keeper was performed to examine minimum inhibitory concentration (MIC) values and minimum bactericidal concentrations (MBC) by serial dilution and bacterial population counts. Soxhlet extractions and Kirby Bauer disc sensitivity testing showed that Nootka rose extracts possessed antibacterial effectiveness against all three bacterial species while stinging nettle extracts were effective against M. luteus. Results for MIC and MBC indicated antibacterial activity against M. luteus and S. aureus for the Nootka rose when using full-strength solutions;all three bacterial species exhibited growth when undiluted stinging nettle treatments were used. When considering bacterial population counts for S. aureus, results indicated that only the Nootka rose treatment offered effective inhibition. Chemical analysis showed that alkaloid percentage was greater in the stinging nettle (0.17%) than Nootka rose (0.07%), while saponin percentage was greater in the Nootka rose (0.87%) than stinging nettle (0.17%). Overall, Nootka rose showed a greater level of antibacterial effectiveness than stinging nettle by Indigenous and Western scientific methods of plant extract preparation.

Stability of High-Order Linear ItôEquations with Delays

A novel general stability analysis scheme based on a non-Lyapunov framework is explored. Several easy-to-check sufficient conditions for exponential p-stability are formulated in terms of M-matrices. Stability analysis of applied second-order It? equations with delay is provided as well. The linearization technique, in combination with the tests obtained in this paper, can be used for local stability analysis of a wide class of nonlinear stochastic differential equations.

Two decades of variable retention in British Columbia: a review of its implementation and effectiveness for biodiversity conservation

Stand-level retention is an important component of sustainable forest management which aims to balance ecological,social and economic objectives.Long-term retention of mature forest structures at the time of harvesting(variable retention)is intended to produce future forest stands that more closely resemble conditions that develop after natural disturbances,thereby maintaining greater diversity of habitats for a variety of organisms.Structure includes features such as live and dead trees representing multiple canopy layers,undisturbed understory vegetation and coarse woody debris.Over the past two decades,variable retention has become common on forest lands in the temperate rainforests of coastal British Columbia(BC)and has been applied to a lesser extent in inland forest types.Our review of studies in BC and in similar forest types in our region indicates that both aggregated and dispersed retention can contribute to biodiversity conservation by providing short-term‘life-boating’habitat for some species and by enhancing the structural characteristics of future stands.For example,greater abundance of species present in the pre-harvest forest have been documented for vegetation,birds,carabid beetles,gastropods,ectomycorrhizal fungi and soil fauna in retention cutblocks compared to clearcuts.There are,however,some negative consequences for timber production such as wind damage to retained trees and reduced growth rates of tree regeneration compared to clearcuts.The authors suggest an adaptive management approach for balancing competing objectives when faced with uncertainty.This includes monitoring the implementation and effectiveness of various strategies for achieving goals.Over two decades of experience applying variable retention harvesting to industrial-scale management of forest lands in BC suggests that it is possible to balance production of wood with biodiversity conservation.