caa a22 4500 469098848 CHVBK 20180323133039.0 cr unu---uuuuu 170328e19920501xx s 000 0 eng 10.1007/BF00317184 doi (NATIONALLICENCE)springer-10.1007/BF00317184 Variability and stability of a dragonfly assemblage [Elektronische Daten] [P. Crowley, D. Johnson] Summary: Using 12 years of monthly sweep-net data from 9-12 permanent sampling stations, we evaluated the variability and stability of the dragonfly assemblage in Bays Mountain Lake (northeastern Tennessee, USA). To do this, we adopted the view that a stable assemblage (i.e. one capable of recovering quickly from disturbances) should have low variability (i.e. high persistence of taxa, relatively constant densities, and high rank concordance), except with disturbances more intense and frequent than those in this system. Moreover, a stable assemblage should contain populations that exhibit density dependence and should tend to remain within a restricted range of densities (boundedness), shifting toward a narrow density interval between generations (attraction). To test some specific predictions derived from these views, we analyzed 12-year sequences of larval population sizes just before the onset of emergence for the 13 dominant dragonfly taxa in the lake. Most but not all of the 13 dominant taxa persisted during the 12-year period. Variabilities of taxon densities, measured as standard deviations across generations of log-transformed population sizes, were representative of the broad range for other invertebrates but somewhat higher than those of terrestrial vertebrates. There were fewer than three significant abundance trends over the 12-year period, and rank concordance between generations was high (W=0.716). Density dependence was detected among some of the dragonfly density sequences by five different methods. Using techniques presented in the companion paper, we found strong indications of both boundedness and attraction in the whole assemblage. We conclude tentatively that an assemblage consisting of at least 11 of the 13 dominant dragonfly taxa at Bays Mountain Lake has low-to-moderate variability and is stable, but that the complete 29-species assemblage is probably not stable at the scale of this single lake. We emphasize the need for coupling such long-term descriptive analyses with studies of responses to experimental disturbances. Springer-Verlag, 1992 Persistence nationallicence Density dependence nationallicence Attraction nationallicence Boundedness nationallicence Rank concordance nationallicence Crowley P. Evolutionary Ecology Research Group, T.H. Morgan School of Biological Sciences, University of Kentucky, 40506, Lexington, KY, USA aut Johnson D. Department of Biological Sciences, East Tennessee State University, 37614, Johnson City, TN, USA aut Oecologia Springer-Verlag 90/2(1992-05-01), 260-269 0029-8549 90:2<260 1992 90 442 https://doi.org/10.1007/BF00317184 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00317184 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Crowley P. Evolutionary Ecology Research Group, T.H. Morgan School of Biological Sciences, University of Kentucky, 40506, Lexington, KY, USA aut NATIONALLICENCE 700 1- Johnson D. Department of Biological Sciences, East Tennessee State University, 37614, Johnson City, TN, USA aut NATIONALLICENCE 773 0- Oecologia Springer-Verlag 90/2(1992-05-01), 260-269 0029-8549 90:2<260 1992 90 442 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer