Joos C.J.,05 Tucker Hall |
Thompson F.R.,University of Missouri |
Faaborg J.,05 Tucker Hall
Journal of Avian Biology | Year: 2014
Variation in habitat quality among territories within a heterogeneous patch should influence reproductive success of territory owners. Further, territory settlement order following an ideal despotic distribution (IDD) should predict the fitness of occupants if territory selection is adaptive. We recorded settlement order and monitored nests in territories occupied by individually marked Bell's vireos Vireo bellii bellii across a range of shrubland habitats in central Missouri, USA. We used an information theoretic approach to evaluate multiple hypotheses regarding the relationship between territory settlement order and seasonal territory productivity (productivity), which we define as the number of young fledged from all nest attempts in a territory. Territory settlement order and arrival date were not analogous and later arriving males displaced early settlers in 13 of 49 territories. Settlement order and lay date together were the best predictors of a territory's productivity; productivity decreased 2.08 young from earliest to latest settlement rank and lay date. Males that defended the same territory in successive years occupied territories with earlier settlement dates, but we found little evidence that age or prior ownership influenced productivity. Territory selection by male Bell's vireos was adaptive because males preferred to settle in territories that had high seasonal offspring production, but even though settlement rank was linked to territory quality, high productivity was only realized on high quality territory when also linked to early nest initiation date. While settlement rank was related to territory quality, obtaining a high quality territory had to be combined with early nest initiation to maximize productivity. We found support for the IDD hypothesis because the highest quality territories, (i.e. most productive), were settled earlier. Research that identifies high quality habitat by linking individual fitness with habitat characteristics may elucidate the importance of habitat quality, individual experience and temporal factors to productivity of Bell's vireos. © 2014 Th e Authors.
Peterman W.E.,05 Tucker Hall |
Peterman W.E.,University of Illinois at Urbana - Champaign |
Anderson T.L.,05 Tucker Hall |
Ousterhout B.H.,05 Tucker Hall |
And 3 more authors.
Conservation Genetics | Year: 2014
Understanding patterns of dispersal, gene flow, and population differentiation are critical to making informed management and conservation decisions. By assessing these processes in multiple sympatric species, we can increase the generality and applicability of management plans. In this study, we assess patterns of genetic differentiation and population structure in two ecologically similar ambystomatid salamanders in Missouri, USA. Ambystoma annulatum (ringed salamander) and A. maculatum (spotted salamander) are both dependent upon forested habitats and fishless ponds for reproduction, but differ in their breeding phenology. In comparing these species, we assessed the support for five different processes that we hypothesized to affect genetic differentiation: (1) resistance of landscape features to movement, (2) distribution of breeding habitat, (3) dispersal propensity, (4) dispersal ability, and (5) breeding habitat quality. Of these hypotheses, we found support for differences in dispersal ability and propensity. In both species, there was a strong pattern of isolation-by-distance. However, A. annulatum exhibited greater overall differentiation (Formula presented.), had a greater rate of differentiation increase with distance, and were grouped into three spatially congruent genetic clusters. In contrast, A. maculatum consisted of a single population cluster and overall (Formula presented.) was 0.047. We estimated the mean genetic dispersal distance of A. annulatum and A. maculatum to be 1,693 m and 2,050 m, respectively. Our results underscore the importance of considering multiple species when developing management criteria to better account for differences in dispersal ability. © 2014, Springer Science+Business Media Dordrecht.