Heterogeneity among species and community dynamics—Norwegian bird communities as a case study

Abstract

We have in this study analysed bird communities across Norway with a heterogeneous species abundance model, where dynamical parameters can vary among species. Similarity in community composition over time, used as a measure of temporal β -diversity or the turnover rate, was then estimated. When we account for heterogeneity in dynamical parameters among species it will affect how we estimate environmental stochasticity, and, subsequently, how the temporal dynamics is modelled. In addition, spatial variation in species abundance within a sampling area can obscure the temporal dynamics of communities. By inadvertently including small-scale spatial variation within sampling areas in the sample noise term, it will be difficult to correctly detect changes in community structure, or species abundance similarity, in time. Using Norwegian bird communities as a case study, we have shown how to interpret the sample correlation of the bivariate Poisson lognormal distribution, fitted to pairs of transects, and why separation of the transects into spatially similar subgroups can be beneficial. This approach also makes us able to account for sampling error and over-dispersion relative to Poisson sampling. The partitioning of the variance of the species abundance distributions showed that heterogeneity among species in temporal dynamics accounted for roughly 75% of the variation, close to estimates for other taxa. High temporal similarity can be interpreted as a low baseline turnover rate, which is important when studying changes to ecosystems due to e.g. anthropogenic effects. Furthermore, the environmental stochasticity was more realistically estimated in this heterogeneous model. This is essential for predicting the dynamics of species abundances forward in time.

Short-lived species move uphill faster under climate change

“…Each survey location has 200 survey points situated along eight to ten survey routes each with 20-25 survey points. The distance between the survey points within a survey route is 200-300 m (Solbu et al 2018) (Fig. 1a), totalling 1400 point counts across an altitudinal range from 200 to 1350 m. At each point count location, a five-minute recording of all birds seen and heard was carried out yearly from late May to early July (one day visit per year).…”

An Evolutionary and Ecological Community Model for Distribution of Phenotypes and Abundances among Competing Species

“…Williams 1964. It also includes a component due to permanent heterogeneity among species of similar magnitude as estimated in natural communities (Engen et al 2002;Lande et al 2003;Grøetan et al 2012Grøetan et al , 2014Solbu et al 2018).…”

“…These analyses led MacArthur (1972, p. 237) to the general conclusion that in competitive communities species will reach equilibrium population sizes such that their resource utilization best matches the production of limiting re-4 such as Hubbell's (2001) neutral model driven by demographic stochasticity and models of single species dynamics dependent on environmental fluctuations (Engen and Lande 1996a,b;Saether et al 2013;Engen et al 2017). Models including environmental stochasticity can be classified by their degree of heterogeneity, that is, the relative amount of variation in abundance among species determined by differences among species in dynamic parameters, often found to be large (Engen et al 2002;Lande et al 2003;Grøtan et al 2012Solbu et al 2018). Heterogeneity implies that differences among species are sufficiently large to generate significant differences in the parameters describing their population dynamics.…”

Short-Lived Species Move Uphill Faster Under Climate Change

“…Each survey location has 200 survey points situated along eight to ten survey routes each with 20-25 survey points. The distance between the survey points within a survey route is 200-300 m (Solbu et al 2018) (Figure 1A), totalling 1400 point counts across an altitudinal range from 200 to 1350 m. At each point count location, ve minute recording of all birds seen and heard were carried out yearly from late May to early July (one day visit per year). The Swedish data follow the " xed routes" (Lindström et al 2013), and span from 1996 to present.…”