Predicting resilience of ecosystem functioning from co‐varying species' responses to environmental change

Understanding how environmental change affects ecosystem function delivery is of primary importance for fundamental and applied ecology. Current approaches focus on single environmental driver effects on communities, mediated by individual response traits. Data limitations present constraints in scaling up this approach to predict the impacts of multivariate environmental change on ecosystem functioning. We present a more holistic approach to determine ecosystem function resilience, using long‐term monitoring data to analyze the aggregate impact of multiple historic environmental drivers on species' population dynamics. By assessing covariation in population dynamics between pairs of species, we identify which species respond most synchronously to environmental change and allocate species into “response guilds.” We then use “production functions” combining trait data to estimate the relative roles of species to ecosystem functions. We quantify the correlation between response guilds and production functions, assessing the resilience of ecosystem functioning to environmental change, with asynchronous dynamics of species in the same functional guild expected to lead to more stable ecosystem functioning. Testing this method using data for butterflies collected over four decades in the United Kingdom, we find three ecosystem functions (resource provisioning, wildflower pollination, and aesthetic cultural value) appear relatively robust, with functionally important species dispersed across response guilds, suggesting more stable ecosystem functioning. Additionally, by relating genetic distances to response guilds we assess the heritability of responses to environmental change. Our results suggest it may be feasible to infer population responses of butterflies to environmental change based on phylogeny—a useful insight for conservation management of rare species with limited population monitoring data. Our approach holds promise for overcoming the impasse in predicting the responses of ecosystem functions to environmental change. Quantifying co‐varying species' responses to multivariate environmental change should enable us to significantly advance our predictions of ecosystem function resilience and enable proactive ecosystem management.     

Similarities in butterfly emergence dates among populations suggest local adaptation to climate

Phenology shifts are the most widely cited examples of the biological impact of climate change, yet there are few assessments of potential effects on the fitness of individual organisms or the persistence of populations. Despite extensive evidence of climate‐driven advances in phenological events over recent decades, comparable patterns across species' geographic ranges have seldom been described. Even fewer studies have quantified concurrent spatial gradients and temporal trends between phenology and climate. Here we analyse a large data set (~129 000 phenology measures) over 37 years across the UK to provide the first phylogenetic comparative analysis of the relative roles of plasticity and local adaptation in generating spatial and temporal patterns in butterfly mean flight dates. Although populations of all species exhibit a plastic response to temperature, with adult emergence dates earlier in warmer years by an average of 6.4 days per °C, among‐population differences are significantly lower on average, at 4.3 days per °C. Emergence dates of most species are more synchronised over their geographic range than is predicted by their relationship between mean flight date and temperature over time, suggesting local adaptation. Biological traits of species only weakly explained the variation in differences between space‐temperature and time‐temperature phenological responses, suggesting that multiple mechanisms may operate to maintain local adaptation. As niche models assume constant relationships between occurrence and environmental conditions across a species' entire range, an important implication of the temperature‐mediated local adaptation detected here is that populations of insects are much more sensitive to future climate changes than current projections suggest.     

Advantages of larval control for African malaria vectors: Low mobility and behavioural responsiveness of immature mosquito stages allow high effective coverage

Background  

Based on sensitivity analysis of the MacDonald-Ross model, it has long been argued that the best way to reduce malaria transmission is to target adult female mosquitoes with insecticides that can reduce the longevity and human-feeding frequency of vectors. However, these analyses have ignored a fundamental biological difference between mosquito adults and the immature stages that precede them: adults are highly mobile flying insects that can readily detect and avoid many intervention measures whereas mosquito eggs, larvae and pupae are confined within relatively small aquatic habitats and cannot readily escape control measures.     

Solution NMR characterization of the thermodynamics of the disulfide bond orientational isomerism and its effect of cluster electronic properties for the hyperthermostable three-iron cluster ferredoxin from the archaeon Pyrococcus furiosus

The thermodynamics and dynamics of the Cys21-Cys48 disulfide "S" if "R" conformational isomerism in the three-iron, single cubane cluster ferredoxin (Fd) from the hyperthermophilic archaeon Pyrococcus furiosus (Pf) have been characterized by (1)H NMR spectroscopy in both water and water/methanol mixed solvents. The mean interconversion rate at 25 degrees C is 3 x 10(3) s(-1) and DeltaG(298) = -0.2 kcal/mol [DeltaH = 4.0 kcal/mol; DeltaS = 14 cal/(mol.K)], with the S orientation as the more stable form at low temperature (< 0 degrees C) but the R orientation predominating at >100 degrees C, where the organism thrives. The distinct pattern of ligated Cys beta-proton contact shifts for the resolved signals and their characteristic temperature behavior for the forms of the 3Fe Fd with alternate disulfide orientations have been analyzed to determine the influences of disulfide orientation and methanol cosolvent on the topology of the inter-iron spin coupling in the 3Fe cluster. The Cys21-Cys48 disulfide orientation influences primarily the spin couplings involving the iron ligated to Cys17, whose carbonyl oxygen is a hydrogen bond acceptor to the Cys21 peptide proton. Comparison of the Cys beta-proton contact shift pattern for the alternate disulfide orientations with the pattern exhibited upon cleaving the disulfide bridge confirms an earlier [Wang, P.-L., Calzolai, L., Bren, K. L., Teng, Q., Jenney, F. E., Jr., Brereton, P. S., Howard, J. B., Adams, M. W. W., and La Mar, G. N. (1999) Biochemistry 38, 8167-8178] proposal that the structure of the same Fd with the R disulfide orientation resembles that of the Fd upon cleaving the disulfide bond.     

Backbone solution structures of proteins using residual dipolar couplings: application to a novel structural genomics target

Structural genomics (or proteomics) activities are critically dependent on the availability of high-throughput structure determination methodology. Development of such methodology has been a particular challenge for NMR based structure determination because of the demands for isotopic labeling of proteins and the requirements for very long data acquisition times. We present here a methodology that gains efficiency from a focus on determination of backbone structures of proteins as opposed to full structures with all sidechains in place. This focus is appropriate given the presumption that many protein structures in the future will be built using computational methods that start from representative fold family structures and replace as many as 70% of the sidechains in the course of structure determination. The methodology we present is based primarily on residual dipolar couplings (RDCs), readily accessible NMR observables that constrain the orientation of backbone fragments irrespective of separation in space. A new software tool is described for the assembly of backbone fragments under RDC constraints and an application to a structural genomics target is presented. The target is an 8.7 kDa protein from Pyrococcus furiosus, PF1061, that was previously not well annotated, and had a nearest structurally characterized neighbor with only 33% sequence identity. The structure produced shows structural similarity to this sequence homologue, but also shows similarity to other proteins, which suggests a functional role in sulfur transfer. Given the backbone structure and a possible functional link this should be an ideal target for development of modeling methods.     

NMR structure of a concatemer of the first and second ligand-binding modules of the human low-density lipoprotein receptor

The ligand-binding domain of the human low-density lipoprotein receptor consists of seven modules, each of 40-45 residues. In the presence of calcium, these modules adopt a common polypeptide fold with three conserved disulfide bonds. A concatemer of the first and second modules (LB(1-2)) folds efficiently in the presence of calcium ions, forming the same disulfide connectivities as in the isolated modules. The three-dimensional structure of LB(1-2) has now been solved using two-dimensional 1H NMR spectroscopy and restrained molecular dynamics calculations. No intermodule nuclear Overhauser effects were observed, indicating the absence of persistent interaction between them. The near random-coil NH and H alpha chemical shifts and the low phi and psi angle order parameters of the four-residue linker suggest that it has considerable flexibility. The family of LB(1-2) structures superimposed well over LB1 or LB2, but not over both modules simultaneously. LB1 and LB2 have a similar pattern of calcium ligands, but the orientations of the indole rings of the tryptophan residues W23 and W66 differ, with the latter limiting solvent access to the calcium ion. From these studies, it appears that although most of the modules in the ligand-binding region of the receptor are joined by short segments, these linkers may impart considerable flexibility on this region.