Scaling range sizes to threats for robust predictions of risks to biodiversity

Assessments of risk to biodiversity often rely on spatial distributions of species and ecosystems. Range‐size metrics used extensively in these assessments, such as area of occupancy (AOO), are sensitive to measurement scale, prompting proposals to measure them at finer scales or at different scales based on the shape of the distribution or ecological characteristics of the biota. Despite its dominant role in red‐list assessments for decades, appropriate spatial scales of AOO for predicting risks of species’ extinction or ecosystem collapse remain untested and contentious. There are no quantitative evaluations of the scale‐sensitivity of AOO as a predictor of risks, the relationship between optimal AOO scale and threat scale, or the effect of grid uncertainty. We used stochastic simulation models to explore risks to ecosystems and species with clustered, dispersed, and linear distribution patterns subject to regimes of threat events with different frequency and spatial extent. Area of occupancy was an accurate predictor of risk (0.81<|r|<0.98) and performed optimally when measured with grid cells 0.1–1.0 times the largest plausible area threatened by an event. Contrary to previous assertions, estimates of AOO at these relatively coarse scales were better predictors of risk than finer‐scale estimates of AOO (e.g., when measurement cells are <1% of the area of the largest threat). The optimal scale depended on the spatial scales of threats more than the shape or size of biotic distributions. Although we found appreciable potential for grid‐measurement errors, current IUCN guidelines for estimating AOO neutralize geometric uncertainty and incorporate effective scaling procedures for assessing risks posed by landscape‐scale threats to species and ecosystems.     

Efficacy of extracting indices from large‐scale acoustic recordings to monitor biodiversity

Passive acoustic monitoring could be a powerful way to assess biodiversity across large spatial and temporal scales. However, extracting meaningful information from recordings can be prohibitively time consuming. Acoustic indices (i.e., a mathematical summary of acoustic energy) offer a relatively rapid method for processing acoustic data and are increasingly used to characterize biological communities. We examined the relationship between acoustic indices and the diversity and abundance of biological sounds in recordings. We reviewed the acoustic‐index literature and found that over 60 indices have been applied to a range of objectives with varying success. We used 36 of the most indicative indices to develop a predictive model of the diversity of animal sounds in recordings. Acoustic data were collected at 43 sites in temperate terrestrial and tropical marine habitats across the continental United States. For terrestrial recordings, random‐forest models with a suite of acoustic indices as covariates predicted Shannon diversity, richness, and total number of biological sounds with high accuracy (R² ≥ 0.94, mean squared error [MSE] ≤170.2). Among the indices assessed, roughness, acoustic activity, and acoustic richness contributed most to the predictive ability of models. Performance of index models was negatively affected by insect, weather, and anthropogenic sounds. For marine recordings, random‐forest models poorly predicted Shannon diversity, richness, and total number of biological sounds (R² ≤ 0.40, MSE ≥ 195). Our results suggest that using a combination of relevant acoustic indices in a flexible model can accurately predict the diversity of biological sounds in temperate terrestrial acoustic recordings. Thus, acoustic approaches could be an important contribution to biodiversity monitoring in some habitats.     

Perceived barriers to and drivers of community participation in protected‐area governance

Protected areas (PAs) are a frequently used conservation strategy, yet their socioeconomic impacts on local communities remain contentious. A shift toward increased participation by local communities in PA governance seeks to deliver benefits for human well‐being and biodiversity. Although participation is considered critical to the success of PAs, few researchers have investigated individuals’ decisions to participate and what this means for how local people experience the costs and benefits of conservation. We explored who participates in PA governance associations and why; the perceived benefits and costs to participation; and how costs and benefits are distributed within and between communities. Methods included 3 focus groups, 37 interviews, and 217 questionnaire surveys conducted in 3 communities and other stakeholders (e.g., employees of a nongovernmental organization and government officials) in PA governance in Madagascar. Our study design was grounded in the theory of planned behavior (TPB), the most commonly applied behavior model in social psychology. Participation in PA governance was limited by miscommunication and lack of knowledge about who could get involved and how. Respondents perceived limited benefits and high costs and uneven distribution of these within and between communities. Men, poorer households, and people in remote villages reported the highest costs. Our findings illustrate challenges related to comanagement of PAs: understanding the heterogeneous nature of communities; ensuring all households are represented in governance participation; understanding differences in the meaning of forest protection; and targeting interventions to reach households most in need to avoid elite capture.     

Effects of age and sex ratios on offspring recruitment rates in translocated black rhinoceros

Success of animal translocations depends on improving postrelease demographic rates toward establishment and subsequent growth of released populations. Short‐term metrics for evaluating translocation success and its drivers, like postrelease survival and fecundity, are unlikely to represent longer‐term outcomes. We used information theory to investigate 25 years of data on black rhinoceros (Diceros bicornis) translocations. We used the offspring recruitment rate (ORR) of translocated females—a metric integrating survival, fecundity, and offspring recruitment at sexual maturity—to detect determinants of success. Our unambiguously best model (AICω = 0.986) predicted that ORR increases with female age at release as a function of lower postrelease adult rhinoceros sex ratio (males:females). Delay of first postrelease reproduction and failure of some females to recruit any calves to sexual maturity most influenced the pattern of ORRs, and the leading causes of recruitment failure were postrelease female death (23% of all females) and failure to calve (24% of surviving females). We recommend translocating older females (≥6 years old) because they do not exhibit the reproductive delay and low ORRs of juveniles (<4 years old) or the higher rates of recruitment failure of juveniles and young adults (4–5.9 years old). Where translocation of juveniles is necessary, they should be released into female‐biased populations, where they have higher ORRs. Our study offers the unique advantage of a long‐term analysis across a large number of replicate populations—a science‐by‐management experiment as a proxy for a manipulative experiment, and a rare opportunity, particularly for a large, critically endangered taxon such as the black rhinoceros. Our findings differ from previous recommendations, reinforce the importance of long‐term data sets and comprehensive metrics of translocation success, and suggest attention be shifted from ecological to social constraints on population growth and species recovery, particularly when translocating species with polygynous breeding systems.     

Fungicidal activity and molecular modeling of fusarubin analogues from Fusarium oxysporum

Abstract

Fusarubin analogues of Fusarium oxysporum f. sp. ciceris were investigated for antifungal activity in vitro against five soil borne phytopathogenic fungi. 3-O-Methyl-8-O-methyl-fusarubin was inhibitory towards S. sclerotiorum (EC₅₀ 0.33?mmol L^?1) and Sclerotium rolfsii (EC₅₀ 0.38?mmol L^?1). A structure–antifungal activity relationship of fusarubin analogues was established from their activity performance. Possible mechanism of action of these compounds was studied using molecular docking and simulations against three target enzymes which revealed receptor ligand binding affinity. Docking of 3-O-methyl-8-O-methyl-fusarubin into the succinate dehydrogenase site revealed formation of salt bridge, hydrogen bond, π–anion, π–alkyl, and Van der Waals interactions.     

Weaning in the guinea pig (<Emphasis Type="Italic">Cavia aperea</Emphasis> f. <Emphasis Type="Italic">porcellus</Emphasis>): Who decides and by what measure?

Offspring should be selected to influence maternal effort to maximize their own fitness, whereas mothers are selected to limit investment in present progeny. In mammals, this leads to a conflict over the amount of milk provided and the timing of weaning. The intensity and time course of such conflict has so far mostly been investigated experimentally in altricial rodents. However, it is expected that offspring options for conflict will depend on developmental state. We therefore investigated in the highly precocial domestic guinea pig (Cavia aperea f. porcellus) who decides over nursing performance and weaning and how pup state influences these decisions. Specifically, we tested whether a threshold mass of pups predicts weaning time. By exchanging older litters against neonates and vice versa, we produced a situation in which females differed in lactational stage from the cross-fostered pups. Our results indicate that females decide about the timing of weaning, as cross-fostered younger pups were weaned at a much younger age than controls and older pups benefited from continuing lactation of foster mothers. Growth rates did not differ in the treatment groups, and different weaning ages resulted in differing weaning mass refuting the hypothesis that weaning is based on a threshold mass of offspring. This constitutes clear evidence that in a precocial rodent, the guinea pig, decisions about maternal care are primarily determined by maternal state and little influenced by pup state despite the extreme precociality of offspring. We suggest that precocial pups show little resistance to early weaning when food is abundant, as they reach sufficient nutritional independence by the middle of lactation to enable independent survival.     

苯系物Lewis酸碱性定量及其应用

本文以正丁醚／水和环己烷／水分配系数的对数差值Ａ作为酸性指数，以氯仿／水和四氯化碳／水分配系数的对数差值Ｂ作为碱性指数来度量苯系物的Ｌｅｗｉｓ酸碱性，阐明Ａ、Ｂ两指数的物理意义，并表征其相互作用的Ｌｅｗｉｓ酸、碱间的分子作用力的大小，定量分析其与Ｋａｍｌｅｔ等人提出了溶剂化显色参数π，α，β间的关系，研究了各种分子间的对酸，碱性的相对贡献，氢键的贡献是主要的，其次是偶极作用的贡献，色散力引起的贡献     

香蕉镰刀菌枯萎病防治药剂的筛选

杀菌剂对香蕉尖孢镰刀菌的毒力测定筛选结果表明，绿亨一号 多菌灵、五氯硝基苯 多菌灵、多菌灵 普克、敌克松 普克等混配药剂对香蕉尖孢镰刀菌的抑制效果最佳，持效期长，可作为防治香蕉枯萎病的土壤消毒剂使用。     

Two herbivore-deterrent iridoid glycosides reduce the in-vitro growth of a specialist but not of a generalist pathogenic fungus of Plantago lanceolata L

Summary. Many secondary plant compounds are involved in defense against both insect herbivores and pathogens. Two secondary plant compounds of Plantago lanceolata, the iridoid glycosides catalpol and its precursor aucubin, are well known for their deterrent effects on generalist and non-adapted specialist insect herbivores. We tested the effects of these compounds on the in-vitro growth of a specialist and generalist fungal pathogen of this host species. Two chemical forms of these iridoids were tested. The glycosides and their aglycones, the products of enzymatic conversion by specific $/Beta$-glucosidase enzymes. The glycosides enhanced growth of both the specialist fungus Diaporthe adunca and the generalist fungus Fusarium moniliforme var. subglutinans. The positive effect of these glycosides on the generalist fungus is in sharp contrast with the generally negative effects of these glysosides on generalist insect herbivores. The aglycones of aucubin and catalpol reduced the growth of the specialist fungus D. adunca, but, contrary to expectation, enhanced the growth of the generalist fungus F. moniliforme var. subglutinans. Effects of aucubin on D. adunca were stronger than effects of catalpol. This was true both for the growth stimulating effects of the glycosides and for the fungitoxic effects of the aglycones. We therefore expect that the effects of these iridoids in P. lanceolata on the specialist fungus will strongly depend on the ratio between catalpol and its precursor aucubin and the chemical form (glycoside or aglycone) in which these compounds are encountered by the fungus during growth. Our results suggest that iridoid glycosides in P. lanceolata can be used as defense against both herbivores and pathogens, but that their effects are highly specific with respect to the natural enemy species that is encountered. Received 11 April 2002; accepted 9 August 2002     

粉葛根腐病的病原鉴定

近年来发现一种严重为害粉葛块根的土传病害。经显微镜直接检查、病原菌分离培养观察、致病性测定及田间病害调查，初步鉴定该病为粉葛镰刀菌根腐病，病原菌为腐皮镰刀菌(Fusarium solani，属半知菌亚门真菌)；该病的发生是由于腐皮镰刀菌与植物线虫复合感染所致。该报道在中国尚属首例。