Strong, Long-Term Temporal Dynamics of an Ecological Network

Nature is organized into complex, dynamical networks of species and their interactions, which may influence diversity and stability. However, network research is, generally, short-term and depict ecological networks as static structures only, devoid of any dynamics. This hampers our understanding of how nature responds to larger disturbances such as changes in climate. In order to remedy this we studied the long-term (12-yrs) dynamics of a flower-visitation network, consisting of flower-visiting butterflies and their nectar plants. Global network properties, i.e. numbers of species and links, as well as connectance, were temporally stable, whereas most species and links showed a strong temporal dynamics. However, species of butterflies and plants varied bimodally in their temporal persistance: Sporadic species, being present only 1–2(-5) years, and stable species, being present (9-)11–12 years, dominated the networks. Temporal persistence and linkage level of species, i.e. number of links to other species, made up two groups of species: Specialists with a highly variable temporal persistence, and temporally stable species with a highly variable linkage level. Turnover of links of specialists was driven by species turnover, whereas turnover of links among generalists took place through rewiring, i.e. by reshuffling existing interactions. However, in spite of this strong internal dynamics of species and links the network appeared overall stable. If this global stability-local instability phenomenon is general, it is a most astonishing feature of ecological networks

A regionally informed abundance index for supporting integrative analyses across butterfly monitoring schemes

1. The rapid expansion of systematic monitoring schemes necessitates robust methods to reliably assess species' status and trends. Insect monitoring poses a challenge where there are strong seasonal patterns, requiring repeated counts to reliably assess abundance. Butterfly monitoring schemes (BMSs) operate in an increasing number of countries with broadly the same methodology, yet they differ in their observation frequency and in the methods used to compute annual abundance indices. 2. Using simulated and observed data, we performed an extensive comparison of two approaches used to derive abundance indices from count data collected via BMS, under a range of sampling frequencies. Linear interpolation is most commonly used to estimate abundance indices from seasonal count series. A second method, hereafter the regional generalized additive model (GAM), fits a GAM to repeated counts within sites across a climatic region. For the two methods, we estimated bias in abundance indices and the statistical power for detecting trends, given different proportions of missing counts. We also compared the accuracy of trend estimates using systematically degraded observed counts of the Gatekeeper Pyronia tithonus (Linnaeus 1767). 3. The regional GAM method generally outperforms the linear interpolation method. When the proportion of missing counts increased beyond 50%, indices derived via the linear interpolation method showed substantially higher estimation error as well as clear biases, in comparison to the regional GAM method. The regional GAM method also showed higher power to detect trends when the proportion of missing counts was substantial. 4. Synthesis and applications. Monitoring offers invaluable data to support conservation policy and management, but requires robust analysis approaches and guidance for new and expanding schemes. Based on our findings, we recommend the regional generalized additive model approach when conducting integrative analyses across schemes, or when analysing scheme data with reduced sampling efforts. This method enables existing schemes to be expanded or new schemes to be developed with reduced within-year sampling frequency, as well as affording options to adapt protocols to more efficiently assess species status and trends across large geographical scales

Diversity of insect pollinators in the Iberian Peninsula

Numerosas observaciones y estudios que se han llevado a cabo en las últimas décadas demuestran que, además de las abejas (Hymenoptera; Anthophila) otros grupos de insectos desempeñan un papel primordial en la polinización entomófila. En este artículo se revisa la información y bibliografía disponible sobre la contribución de los principales polinizadores tradicionalmente considerados como "secundarios": los coleópteros, los lepidópteros, los dípteros, las avispas y las hormigas. Para cada uno de estos grupos se sigue un esquema común, con una breve introducción, la enumeración de las características básicas -tanto morfológicas como de comportamiento- en relación con la polinización, su efectividad como polinizadores y el estatus de conservación en la península ibérica. Esta revisión pone de manifiesto la importancia de todos estos grupos en la polinización entomófila y la necesidad de incluirlos en estudios exhaustivos sobre este fenómeno. Aunque los datos existentes en general son muy limitados, también se evidencia un declive general en la mayoría de estos grupos y una necesidad apremiante de mejorar los conocimientos sobre sus tendencias poblacionales.Numerous observations and studies that have been carried out in recent decades show that, in addition to bees ((Hymenoptera; Anthophila), other groups of insects play a major role in entomophilous pollination. This article reviews the information and literature available on the contribution of the main groups of pollinators that traditionally have been considered as "secondary": beetles, butterflies and moths, dipterans, wasps and ants. For each of these groups a common outline is followed, with a brief introduction, a summary of the basic characteristics - both morphological and behavioral - in relation to pollination, their effectiveness as pollinators and their conservation status in the Iberian Peninsula. This review highlights the importance of all these groups in entomophilous pollination and the need to include them in comprehensive studies on this phenomenon. Although data are generally very limited, there is clear evidence of a general decline in most of these groups which calls for a pressing need to improve knowledge about their population trends

MEDIDAS PARA LA CONSERVACIÓN DE LA BIODIVERSIDAD DE LOS POLINIZADORES SILVESTRES EN LA PENÍNSULA IBÉRICA

Los científicos y científicas abajo firmantes consideramos muy importante hacer llegar a instituciones, agricultores/as y a la sociedad en general, la necesidad urgente de implementar conjuntamente medidas y cambios que consigan frenar el declive de los polinizadores silvestres ocasionado por la actividad humana. Durante la última década, son múltiples los estudios que alertan de la creciente desaparición de los polinizadores por todo el mundo, en concreto de las abejas silvestres, (Biesmeijer et al. 2006; Potts et al. 2010; Burkle et al. 2013), y de las graves consecuencias que su déficit podría provocar sobre la biodiversidad global (Biesmeijer et al. 2006; Burkle et al. 2013; Lundgren et al. 2016) y sobre la producción agrícola (Aizen y Harder 2009; Garibaldi et al. 2013). No debemos olvidar que la península Ibérica es, por su condición mediterránea y su proximidad al continente africano, uno de los lugares con mayor diversidad de polinizadores de la Unión Europea y, en concreto, una de las zonas con mayor diversidad de abejas del mundo (Michener 2007; Nieto et al. 2014). Hasta el momento, el número de especies de abejas en España presentes en la zona íbero-balear es algo superior a 1.100, cifra a la que cabe añadir algunas especies exclusivas de Portugal más los nuevos hallazgos de los últimos años (Ortiz-Sánchez 2011). Esta gran diversidad de abejas y polinizadores en general está asociada al gran número de especies de plantas con flor presentes en la península Ibérica, alrededor de las 7.000 especies (Aguado Martín et al. 2015). En cuanto al número de mariposas y polillas (lepidópteros) se estima que existen en la península Ibérica unas 5.000 especies (Stefanescu et al. 2018). Más difícil es estimar el número exacto de especies de escarabajos florícolas (coleópteros polinizadores), pero atendiendo a la riqueza de los principales géneros podemos estimar su número en más de 750 (Stefanescu et al. 2018). Somos conscientes de que, a pesar del desarrollo explosivo de los últimos 10 años de la investigación en ecología y gestión de la polinización de los cultivos por insectos silvestres, hoy en día son numerosas las lagunas de conocimiento básico y aplicado sobre el estado de conservación de los insectos polinizadores silvestres. Y es, bajo esta premisa, que presentamos este trabajo de revisión de la literatura científica sobre insectos polinizadores desde principios del siglo XX hasta ahora, cuyo resultado ha quedado plasmado en una lista, no exhaustiva, de los aspectos que consideramos fundamentales para el desarrollo y debate de esta relevante cuestió

Biodegradation of fuel oxygenates and their effect on the expression of a newly identified cytochrome P450 gene in Achromobacter xylosoxidans MCM2/2/1

10.1016/j.procbio.2013.09.028Achromobacter xylosoxidans MCM2/2/1 was enriched and isolated from gasoline-contaminated soil and was found to degrade ethyl tert-butyl ether (ETBE) and methyl tert-butyl ether (MTBE) by 41.48% and 34.15%, respectively, in 6 days. Furthermore, the effect of MTBE and TBA on the expression of cytochrome P450 (CYP) of A. xylosoxidans MCM2/2/1 was examined. The presence of the CYP gene in this organism was first confirmed by amplification of a putative 350 bp CYP gene fragment followed by identification of the entire gene by genome walking and DNA-sequencing. The identified CYP gene of A. xylosoxidans MCM2/2/1 shares a high similarity of about 88% with the thcB gene of A. xylosoxidans A8. Gene expression studies have shown that the CYP gene is expressed in A. xylosoxidans MCM2/2/1; however, the expression of this gene was altered at different concentrations of MTBE

Dark fermentative hydrogen and ethanol production from biodiesel waste glycerol using a co-culture of Escherichia coli and Enterobacter sp.

In previous comparative studies, Enterobacter spH1 was selected as the best hydrogen and ethanol producer (Knothe, 2010). Here, glycerol fermentation was compared between three other strains: Escherichia coli CECT432, Escherichia coli CECT434 and Enterobacter cloacae MCM2/1. E. coli CECT432 was found to perform best with a H2 productivity of 69.1 mM (1307 mL/L). A co-culture of this E. coli CECT432 strain with the earlier selected Enterobacter spH1 showed a 3.1-fold higher H2 productivity (4767 mL/L) from pure glycerol and higher biomass production. Remarkably, the hydrogen yield per mol of glycerol also increased from 0.61 to 1.26 mol H2/mol glycerol. The co-culture was also tested using waste glycerol from biodiesel. Waste glycerol was characterized and found to consist of (w/v): glycerol 47.5%, water 40.5%, ash content 4.8% and non-glycerol organic matter (MONG) 7.2%. The amount of total soluble organic carbon (TOC) in the crude glycerol was 317 g/L. A maximum H2 yield and ethanol yield of 1.53 and 1.21 mol/mol glycerol was obtained on the waste glycerol, respectively. These yields are the highest reported to date using mesophilic strains. The strains metabolized the crude glycerol without any purification step. The ability to produce H2 without prior purification of the waste glycerol is attractive because it avoids extra costs in the process.</p