Species–area relationships are modulated by trophic rank, habitat affinity, and dispersal ability
Noordwijk, C.G.E. ; Verberk, W.C.E.P. ; Turin, H. ; Heijerman, Th. ; Alders, K. ; Deconinck, W. ; Hannig, K. ; Regan, E. ; McCormack, S. ; Brown, M.J. ; Remke, E. ; Siepel, H. ; Berg, M.P. ; Bonte, D. - \ 2015
Ecology 96 (2015)2. - ISSN 0012-9658 - p. 518 - 531.
abundance-occupancy relationships - ground beetles coleoptera - insect communities - calcareous grasslands - population-density - forest fragments - tropical forest - body-size - traits - conservation
In the face of ongoing habitat fragmentation, species–area relationships (SARs) have gained renewed interest and are increasingly used to set conservation priorities. An important question is how large habitat areas need to be to optimize biodiversity conservation. The relationship between area and species richness is explained by colonization–extinction dynamics, whereby smaller sites harbor smaller populations, which are more prone to extinction than the larger populations sustained by larger sites. These colonization– extinction dynamics are predicted to vary with trophic rank, habitat affinity, and dispersal ability of the species. However, empirical evidence for the effect of these species characteristics on SARs remains inconclusive. In this study we used carabid beetle data from 58 calcareous grassland sites to investigate how calcareous grassland area affects species richness and activity density for species differing in trophic rank, habitat affinity, and dispersal ability. In addition, we investigated how SARs are affected by the availability of additional calcareous grassland in the surrounding landscape. Beetle species richness and activity density increased with calcareous grassland area for zoophagous species that are specialists for dry grasslands and, to a lesser extent, for zoophagous habitat generalists. Phytophagous species and zoophagous forest andwet-grassland specialistswere not affected by calcareous grassland area. The dependence of species on large single sites increased with decreasing dispersal ability for species already vulnerable to calcareous grassland area. Additional calcareous grassland in the landscape had a positive effect on local species richness of both dry-grassland specialists and generalists, but this effect was restricted to a few hundred meters. Our results demonstrate that SARs are affected by trophic rank, habitat affinity, and dispersal ability. These species characteristics do not operate independently, but should be viewed in concert. In addition, species’ responses depend on the landscape context. Our study suggests that the impact of habitat area on trophic interactions may be larger than previously anticipated. In small habitat fragments surrounded by a hostile matrix, food chains may be strongly disrupted. This highlights the need to conserve continuous calcareous grassland patches of at least several hectares in size.
Common genetic loci influencing plasma homocysteine concentrations and their effect on risk of coronary artery disease
Meurs, J.B.J. van; Pare, G. ; Schwartz, S.M. ; Hazra, A. ; Tanaka, T. ; Vermeulen, S.H. ; Cotlarciuc, I. ; Yuan, X. ; Malarstig, A. ; Bandinelli, S. ; Bis, J.C. ; Morn, H. ; Brown, M.J. ; Chen, C. ; Chen, Y.D. ; Clarke, R.J. ; Dehghan, A. ; Erdmann, J. ; Ferrucci, L. ; Hamsten, A. ; Hofman, A. ; Hunten, D.J. ; Goel, A. ; Johnson, A.D. ; Kathiresan, S. ; Kampman, E. ; Kiel, D.P. ; Kiemeney, L.A. ; Chambers, J.C. ; Kraft, P. ; Lindemans, J. ; McKnight, B. ; Nelson, C.P. ; O'Donnell, C.J. ; Psaty, B.M. ; Ridken, P.M. ; Rivadeneira, F. ; Rose, L.M. ; Seedoif, U. ; Siscovick, D.S. ; Schunkert, H. ; Selhub, J. ; Ueland, P.M. ; Vollenweiden, P. ; Waeben, G. ; Waterworth, D.M. ; Watkins, H. ; Witteman, J.C.M. ; Heijen, M. den; Jacques, P. ; Uitterlinden, A.G. ; Koonet, J.S. ; Rader, D.J. ; Reilly, M.P. ; Moose, V. ; Chasman, D.I. ; Samani, N.J. ; Ahmadi, K.R. - \ 2013
American Journal of Clinical Nutrition 98 (2013)3. - ISSN 0002-9165 - p. 668 - 676.
genome-wide association - cardiovascular-disease - mendelian randomization - heart-disease - expression - metaanalysis - mthfr - polymorphism - women - identification
Background: The strong observational association between total homocysteine (tHcy) concentrations and risk of coronary artery disease (CAD) and the null associations in the homocysteinelowering trials have prompted the need to identify genetic variants associated with homocysteine concentrations and risk of CAD. Objective: We tested whether common genetic polymorphisms associated with variation in tlicy are also associated with CAD. Design: We conducted a meta-analysis of genome-wide association studies (GWAS) on tHcy concentrations in 44,147 individuals of European descent. Polymolphisms associated with tHcy (P <10(-8)) were tested for association with CAD in 31,400 cases and 92,927 controls. Results: Common variants at 13 loci, explaining 5.9% of the variation in tHcy, were associated with tHcy concentrations, including 6 novel loci in or near MMACHC (2.1 X 10(-9)), SLC17A3 (1.0 x 10(-8)), GTPB10 (1.7 X 10(-8)), CUBN (7.5 X 10(-1)), HNFlA (1.2 x 10(-12)), and FUT2 (6.6 x 10(-9)), and variants previously reported at or near the MTHFR, MTR, CPS1, MUT, NOX4, DPEP1, and CBS genes. Individuals within the highest 10% of the genotype risk score (GRS) had 3-gmol/L higher mean tHcy concentrations than did those within the lowest 10% of the GRS (P = 1 X 10(-36)). The GRS was not associated with risk of CAD (OR: 1.01; 95% CI: 0.98, 1.04; P = 0.49). Conclusions: We identified several novel loci that influence plasma tHcy concentrations. Overall, common genetic variants that influence plasma tHcy concentrations are not associated with risk of CAD in white populations, which further refutes the causal relevance of moderately elevated tHey concentrations and tHcy-related pathways for CAD.