Are Swiss birds tracking climate change?

Abstract

a b s t r a c tClimate change is affecting biodiversity worldwide inducing species to either "move, adapt or die". In this paper we propose a conceptual framework for analysing range shifts, namely a catalogue of the possible patterns of change in the distribution of a species along elevational or other environmental gradients and an improved quantitative methodology to identify and objectively describe these patterns. Patterns are defined in terms of changes occurring at the leading, trailing or both edges of the distribution: (a) leading edge expansion, (b) trailing edge retraction, (c) range expansion, (d) optimum shift, (e) expansion, (f) retraction, and (g) shift. The methodology is based on the modelling of species distributions along a gradient using generalized additive models (GAMs). Separate models are calibrated for two distinct periods of assessment and response curves are compared over five reference points. Changes occurred at these points are formalized into a code that ultimately designates the corresponding change pattern. We tested the proposed methodology using data from the Swiss national common breeding bird survey. The elevational distributions of 95 bird species were modelled for the periods 1999-2002 and 2004-2007 and significant upward shifts (all patterns confounded) were identified for 35% of the species. Over the same period, an increase in mean temperature was registered for Switzerland. In consideration of the short period covered by the case study, assessed change patterns are considered to correspond to intermediate patterns in an ongoing shifting process. However, similar patterns can be determined by habitat barriers, land use/land cover changes, competition with concurrent or invasive species or different warming rates at different elevations.

Winners and losers: How the elevational range of breeding birds on Alps has varied over the past four decades due to climate and habitat changes

“…Thus, we were forced to use a modeling approach to first assess the yearly species distribution, and subsequently, analyze its temporal trend. Indeed, for each species, we calculated the annual elevational distribution curve following the "curve response shape" method (Heegaard, 2002;Maggini et al, 2011), which defines a presence probability curve for a bird species along the elevational gradient. The curve was assessed as a smooth function (thin plate regression spline; Wood, 2017) of the elevation, other than northing and easting to account for spatial autocorrelation, using generalized additive models (Maggini et al, 2011;Wood, 2017).…”

“…Indeed, for each species, we calculated the annual elevational distribution curve following the "curve response shape" method (Heegaard, 2002;Maggini et al, 2011), which defines a presence probability curve for a bird species along the elevational gradient. The curve was assessed as a smooth function (thin plate regression spline; Wood, 2017) of the elevation, other than northing and easting to account for spatial autocorrelation, using generalized additive models (Maggini et al, 2011;Wood, 2017). We set the maximum degrees of freedom to three for the elevation, in order to avoid overfitting and to obtain unimodal curves, and 15 for the space smooth (geographic coordinates; Maggini et al, 2011;Massimino et al, 2015).…”

Central-marginal population dynamics in species invasions

“…To test this prediction, one may compare patches at the range center with similar sizes to those close to range margins to determine whether the population size or boundary changes are of a smaller magnitude than those of marginal populations. It would be reasonable to assume that patches within the invaded FIGURE 7 | (A) Without physical barriers, the deviation of the abundance curve of a species from Gaussian distribution may indicate the migration direction under warming climates (in northern hemisphere; e.g., Maggini et al, 2011). Here, the population or the whole species range is moving toward the left where the abundance curve shows a much steeper slope than the right side.…”

Ignoring biotic interactions overestimates climate change effects: The potential response of the spotted nutcracker to changes in climate and resource plants

“…Species range shifts lead to major changes in ecosystem structure, function and species' interactions when interacting species respond differently to climate change (Walther et al, 2002), causing predominantly negative consequences for biodiversity (Blois et al, 2013;Böhning-Gaese & Lemoine, 2004). Shifts in geographic ranges in response to anthropogenic climate change such as upward shifts in tree line and northward shifts of range boundaries have already been observed (Chen, Hill, Ohlemüller, Roy, & Thomas, 2011;Lenoir, Gégout, Marquet, de Ruffray, & Brisse, 2008;Maggini et al, 2011). For interacting species, such range shifts could lead to a mismatch of the areas where each of the species is able to persist (Kissling et al, 2010;Schweiger et al, 2012).…”