Using worldwide edaphic data to model plant species niches: An assessment at a continental extent

<div><p>Ecological niche modeling (ENM) is a broadly used tool in different fields of plant ecology. Despite the importance of edaphic conditions in determining the niche of terrestrial plant species, edaphic data have rarely been included in ENMs of plant species perhaps because such data are not available for many regions. Recently, edaphic data has been made available at a global scale allowing its potential inclusion and evaluation on ENM performance for plant species. Here, we take advantage of such data and address the following main questions: What is the influence of distinct predictor variables (e.g. climatic vs edaphic) on different ENM algorithms? and what is the relationship between the performance of different predictors and geographic characteristics of species? We used 125 plant species distributed over the Neotropical region to explore the effect on ENMs of using edaphic data available from the SoilGrids database and its combination with climatic data from the CHELSA database. In addition, we related these different predictor variables to geographic characteristics of the target species and different ENM algorithms. The use of different predictors (climatic, edaphic, and both) significantly affected model performance and spatial complexity of the predictions. We showed that the use of global edaphic plus climatic variables generates ENMs with similar or better accuracy compared to those constructed only with climate variables. Moreover, the performance of models considering these different predictors, separately or jointly, was related to geographic properties of species records, such as number and distribution range. The large geographic extent, the variability of environments and the different species’ geographical characteristics considered here allowed us to demonstrate that global edaphic data adds useful information for plant ENMs. This is particularly valuable for studies of species that are distributed in regions where more detailed information on soil properties is poor or does not even exist.</p></div

Cerrados in Argentina? Structure, diversity and biogeography of the woody component of a savanna in the Misiones Province

<div><p>Abstract The Teyú Cuaré field, in Misiones province, Argentina, has been renowned for its flora and physiognomy, which led researchers to indicate that it could be a relict of Cerrado biome. We analyzed the floristic structure of the woody component of a savanna community in this site, and discussed the processes that could contribute to the permanence of this vegetation type over time. Perimeter and height of all woody individuals ≥ 10 cm of perimeter at soil height were collected in 12 square plots (400 m2 each one). We found 15 families and 17 species in our site and compared the woody flora surveyed at this site with the flora of other Cerrado áreas from Brazil and Paraguay. Leptolobium elegans had the highest importance value. The woody flora of the área is closely related to the Cerrado areas from Paraná state in Brazil and Canindeyú and Amambay in Paraguay. This site probably reflects old open physiognomies which were predominant in Misiones and Southern of Brazil in the late Pleistocene and middle Holocene. We inferred that the permanence of open physiognomies at Teyú Cuaré is probably related to mechanisms that act at different levels, such as geological, edaphic, anthropic, and fire disturbance.</p></div

Experimental design for testing the effect of using edaphic variables in ENMs for plant species.

<p>Experimental design for testing the effect of using edaphic variables in ENMs for plant species.</p

Examples of change in suitability predicted by SVM models for three species derived from the use of three predictors set.

<p>C: models with climate predictors, CE: models with climate and edaphic predictors, E: models with edaphic predictors.</p

Mean and confidence interval of Kendall rank correlation coefficient (τ) of pair comparison of suitability.

<p>(A) Suitability comparison between models with predictors sets for different algorithm. (B) Suitability comparison between algorithms for different predictors sets. C: models with climate predictors, CE: models with climate and edaphic predictors, E: models with edaphic predictors.</p

Climate and edaphic variables (names and units) used as predictors in plant ecological niche models.

<p>Climate and edaphic variables (names and units) used as predictors in plant ecological niche models.</p

Results of the repeated measures ANOVA for the TSS, TPR, AUC and SI, considering the algorithm (GAM, MEql, SVM and RF) and predictor (climate, climate-edaphic, edaphic) factors.

<p>Results of the repeated measures ANOVA for the TSS, TPR, AUC and SI, considering the algorithm (GAM, MEql, SVM and RF) and predictor (climate, climate-edaphic, edaphic) factors.</p

Summary of linear mixed effect models for four algorithms and the significance of covariates.

<p>The model selection was based on the likelihood ratio test.</p

Cerrados in Argentina? Structure, diversity and biogeography of the woody component of a savanna in the Misiones Province. Rodriguésia 69(2): 335-349. 2018. - Supplementary data

<p>Supplementary data 1: PDF file with pedological descriptions, and the physical and chemical analysis of soil profiles of the Teyú Cuaré savanna and forest.<br></p><p>Supplementary data 2: PDF file with descriptions of the Cerrado sites used to perform the ordination and cluster analysis.</p><p>Supplementary data 3: It is a CSV archive with the presences-absences matrix used to perform ordination and cluster analysis. This database also contains the singletons which were not used in our analysis.<br></p><p>Supplementary data 4: Photo of a stone found with Guarani ceramics in San Ignacio, which represents part of a tool, locally known as boleadeira.</p><p>Supplementary data 5: It is a CSV archive with the raw data of the survey performed in the Teyú Cuaré savanna.</p

Correlation of variations in species abundance of Atlantic forests regenerating on abandoned pastures with different environmental and spatial variables

The conversion of native forests into pastures is still a common practice in Brazil. Abandoned pastures have great potential for natural regeneration and therefore could play an important role in meeting the enormous demand for forest restoration. Few studies, however, have investigated the extent to which spatially-structured environmental variables and community structure are correlated with the variation in species abundance of regenerating forests on abandoned pastures. Therefore, we aimed to determine whether environmental and spatial variables were capable of explaining the variation in abundance of woody species on abandoned pastures in the subtropical Atlantic Forest. We systematically distributed 45 sample plots with size and inclusion criteria that changed according to the vegetation layer in three different abandoned pastures. In general, most of the variation in species abundance that our models were able to explain was correlated with spatially-unstructured physical-chemical soil properties. A smaller part of the variation was correlated with spatially-structured soil variables and topography-related variables. An even smaller portion of the variation was spatially-structured but was not correlated with spatially-structured environmental variables. Therefore, our results suggest that the variation in species abundance of regenerating subtropical Atlantic forests on abandoned pastures is more closely related to niche-based processes mediated by environmental variables than to stochastic spatial processes.</p