Modelling landscape constraints on farmland bird species range shifts under climate change
Graphical abstract
Introduction
Many studies have attempted to estimate the future effects of global environmental changes on biodiversity (e.g., Thuiller et al., 2005, Araújo et al., 2006, Garcia et al., 2011). Many of these studies examine the effect of climate change alone, leaving aside the effects of non-climatic drivers (e.g., Harfoot et al., 2014, Morelli and Tryjanowski, 2015, Titeux et al., 2016). However, the effects of climate change on biodiversity can be influenced by interactions with other components of global change (e.g., Clavero et al., 2011, Hof et al., 2011, Maxwell et al., 2016), particularly with land use changes and related effects on other pressures such as water regime (e.g., Jetz et al., 2007, Rosenzweig et al., 2008, Thuiller et al., 2014a; Newbold et al., 2016).
Both climate and land cover changes are considered major drivers of global biodiversity change (Sala et al., 2000, Jetz et al., 2007, de Chazal and Rounsevell, 2009). However, climate is often regarded as the most important driver at large spatial extents and coarse spatial resolutions (e.g., Thuiller et al., 2004a, Luoto et al., 2007, Triviño et al., 2011). The relative contribution of climate and land cover on future species range shift projections remain poorly explored (Pearce-Higgins and Green, 2014; but see studies from Table S1, Appendix A). Previous studies have found that land cover can be correlated with climate and that including land cover variables did not improve the accuracy of species distribution models, as expected (e.g., Seoane et al., 2003, Thuiller et al., 2004a, Triviño et al., 2011, Reino et al., 2013). Although climate and land cover are generally correlated, however, climate does not necessarily fully control land cover, which may be affected by a number of additional factors such as soil type, topography, socio-economic contexts and policies (Veldkamp and Lambin, 2001, Ribeiro et al., 2014, Ribeiro et al., 2016). In addition, because climate and land cover often play key roles at different spatial scales (Pearson et al., 2004), they are likely to show different geographical patterns of change and hence may affect different regions in a distinct way. Moreover, climate and landscape drivers may interact in their effect on species geographical range, because the two drivers may have different effects on different groups of species (Opdam and Wascher, 2004, Sohl, 2014, Jarzyna et al., 2015).
Most studies modelling the consequences of changes in the structural component of landscape have ignored potentially important processes related to landscape fragmentation (e.g., Vallecillo et al., 2009, Triviño et al., 2011), although they have been shown to be determinant for some species (Jarzyna et al., 2015). This is the case, for instance, of some farmland bird specialists that were shown to be very sensitive to habitat fragmentation at several spatial scales (Reino et al., 2009, Reino et al., 2013). There is a well-established idea that generalist species tend to cope better with environmental changes than specialist species (Gilman et al., 2010, Clavel et al., 2011, Davey et al., 2012, Lurgi et al., 2012, Case et al., 2015). However, at the same time, some studies point to an idiosyncratic nature of species responses to climate change, making it difficult to draw generalizations (e.g., Mair et al., 2012, Moritz and Agudo, 2013, Sohl, 2014). For example, in a recent study, Princé et al. (2015) found that the relative sensitivity of farmland bird specialists and generalists to climate and land cover changes varied among the different global change scenarios that were considered.
Here we model the relative importance of changes at the landscape level on range shifts predictions under future environmental change scenarios, aiming at bringing new insights on the interplay of three component of the environment: biosphere, atmosphere and anthroposphere. We focused on farmland birds in the Iberian Peninsula, considering both climate change and changes in land cover and landscape structure, mainly as the result of land abandonment and changes in agricultural practices, associated with three socioeconomic scenarios for the period of 2021 to 2050. We hypothesize that taking into account changes in landscape composition and structure will potentially strongly affect predictions of farmland bird geographical ranges under climate change scenarios. We also expect that the potential impacts of landscape changes on farmland bird geographical ranges is dependent on the degree of habitat specialization (Clavel et al., 2011), namely the association to farmland landscapes. The overarching goal of this study is thus to examine the proposition that landscape changes should be accounted for when forecasting the effects of environmental changes on the distribution of species highly sensitive to landscape structure.
Section snippets
Data
We used distributional records for 21 Iberian farmland bird species (Table 1), obtained from the most recent breeding bird atlas from Spain (Martí and Moral, 2003) and Portugal (Equipa Atlas, 2008), reporting the occurrence of bird species in 5923 10 × 10 km resolution UTM cells. These are the highest-resolution bird distribution data available for Iberia. Farmland birds selected for this study include species with different degrees of habitat specialization to open habitats, because these seem to
Model performance
The incorporation of landscape variables in the climate-based models consistently improved model's discrimination ability, as measured with mean cross-validation AUC values (Wilcoxon signed rank test, p < 0.001). However, the contribution of landscape variables did not increase substantially the discrimination ability of models, with percent (%) of improvements varying from 0.06% for Calandrella rufescens to 4.68% for Circus pygargus (Table 1). The species Landscape Specialization Index was
Discussion
Our results confirm the hypothesis that the inclusion of landscape variables in species distribution models strongly affect range shift predictions of Iberian farmland birds, despite a generally low contribution to models' performance. Overall, the resulting species distribution models predict that habitat specialists will tend to expand their range, whereas generalists will tend to retract under climate change scenarios. However, in many cases, the inclusion of landscape variables in the
Conclusions
This study underpins the need to consider landscape composition and structure when modelling species range shifts under future climate scenarios. This is particularly the case for habitat specialists, which are strongly constrained by habitat availability and configuration. In addition, our models show that specialist species (many with relevant European conservation concern, Table S2) produce less optimistic predictions when landscape changes are also accounted for. The interplay between
Acknowledgments
This study was funded by the Portuguese Ministry of Science, Technology and Higher Education and the European Social Fund, through the Portuguese Foundation of Science and Technology (FCT), under POPH - QREN - Typology 4.1, through the grants SFRH/BPD/93079/2013 (L.R.) and the contract (IF/01304/2015) (PS) under the IF Researcher Programme and through the project PTDC/BIA-BIC/2203/2012-FCOMP-01-0124-FEDER-028289 by FEDER Funds through the Operational Programme for Competitiveness Factors –
References (70)
- et al.
Ensemble forecasting of species distributions
Trends Ecol. Evol.
(2007) - et al.
Exposure of European biodiversity to changes in human-induced pressures
Environ. Sci. Pol.
(2008) - et al.
Relative sensitivity to climate change of species in northwestern North America
Biol. Conserv.
(2015) - et al.
Land-use and climate change within assessments of biodiversity change: a review
Glob. Environ. Chang. Hum. Policy Dimens.
(2009) - et al.
Spatial analysis and modeling of land-use distributions in Belgium
Comput. Environ. Urban. Syst.
(2007) - et al.
A framework for community interactions under climate change
Trends Ecol. Evol.
(2010) - et al.
Climate change meets habitat fragmentation: linking landscape and biogeographical scale levels in research and conservation
Biol. Conserv.
(2004) - et al.
Distance to edges, edge contrast and landscape fragmentation: interactions affecting farmland birds around forest plantations
Biol. Conserv.
(2009) - et al.
Modelling farming system dynamics in high nature value farmland under policy change
Agric. Ecosyst. Environ.
(2014) - et al.
A coherent set of future land-use change scenarios for Europe
Agric. Ecosyst. Environ.
(2006)