Large‐scale environmental correlates of forest tree distributions in Catalonia (NE Spain)

Abstract

Aim To explore the environmental correlates of tree species distributions in Catalonia according to the chorological status of the species. Location The study area is the region of Catalonia, in north‐eastern Spain. Methods We used presence‐absence data for 24 species, sampled in random plots distributed throughout forests of Catalonia. A climate model for the Catalonia region provided environmental variables. We used classification tree analysis to explore the environmental correlates of the realized niches of tree species. The predictive accuracy of the models was assessed using the ROC curve approach. Potential distribution maps of tree species were generated for the whole Catalonia region. Results Models were ranked from low to high accuracy for the 24 species. Differences in accuracy among species were related to the chorological status of species. Zonal species, or species at the core of their range (Mediterranean and Sub‐Mediterranean species), were generally well predicted, while extrazonal species, or species at the edge of their range, were predicted only moderately well. Mediterranean species distributions showed good correlations with extreme temperatures and annual precipitation. Main conclusions The above trends confirmed the difficulty of identifying the realized niche of species at the edges of their ranges. In contrast, Mediterranean and Sub‐Mediterranean species, which were at the core of their range, were well‐predicted, confirming the importance of extremes of temperature and annual precipitation as effective surrogates for variables having more direct physiological roles in limiting the ability of plants to survive and grow. Maps of potential tree distributions allowed us to define suitable habitats and to highlight areas where species have been planted outside their natural distribution.

Comparing Suitable Habitat Models to Predict Rare and Endemic Plant Species Distributions: What are the Limits of the Niche of Cola lorougnonis (Malvaceae) in Cote d'Ivoire?

“…The first group concerned eleven (11) species that have their predictive accuracy value between 0.9 and 1 ( Table 2), meaning that most of the individual models had a good fit for these species. For these species, our results are considered excellent (Thuiller et al, 2003). The maximum values of AUC was 0.99 observed for Cola lorougnonis the main species which is rare, endanger and endemic in Côte d'Ivoire (IUCN, 1994;Vroh et al, 2014, Aké-Assi, 2001-2002.…”

Frequency, not relative abundance, of temperate tree species varies along climate gradients in eastern North America

“…Although there is a rich literature relating plant performance to a wide range of climatic variables that can be derived from data on temperature and precipitation (e.g., Thuiller et al 2003), we have focused our analyses on two primary climate variables: average annual mean temperature and average annual precipitation. Our reasons are based on both pragmatism and principle.…”

“…Much of the recent research on the potential implications of climate change for the distribution and abundance of tree species has focused on coarse, continental-scale distributions of species as a function of climate, often based solely on presence-absence data across the current geographic ranges of tree species (i.e., Thuiller et al 2003, McKenney et al 2007). The resulting ''climate-envelope'' models have been widely used (e.g., Huntley et al 1995, McKenney et al 2007 and their merits widely debated (Loehle andLeBlanc 1996, Jeschke andStrayer 2008), but even the criticisms of climate-envelope models typically do not seek to change the scale of interest from very coarse patterns of presence-absence at a continental scale.…”

“…There are a number of challenges, including distinguishing between fundamental and realized niches (Vetaas 2002, Canham et al 2006, identifying operationally defined climate variables (Thuiller et al 2003), and assessing the degree to which geographic distributions can track climate change due to limitations in plant migration rates (Clark et al 2003, Holt et al 2005. In many cases, range limits are treated as realized climate niches (i.e., Thuiller et al 2003, Manthey andBox 2007), without consideration of the dynamic, metapopulation structure of plant distributions at the landscape scale.…”

Multiscale computation of solar radiation for predictive vegetation modelling

“…We compared distribution models realised without solar radiation values and others including Helios irradiation, considered alone or integrated in water balance calculations. In the first time, we modelled the species distribution according to four ecological variables relevant to characterisation of plant distribution [16,38,43,49]: mean annual temperature (MaT), mean annual precipitation (MaP), altitude, and soil pH. These variables were extracted from four GIS data layers: AURELHY model at 1 km 2 resolution for MaT and MaP [2], DEM from the French Geographic Institute (IGN) at 50 m resolution for altitude, and pH from unpublished map elaborated with plant indicator values and used successfully to predict Acer campestre and Vaccinium myrtillus distribution [7,8].…”