Aim The presence‐only data stored in natural history collections is the most important source of information available regarding the distribution of organisms. These data and profile techniques can be used to generate species distribution models (SDMs), but pseudo‐absences must be generated to use group discriminative techniques. In this study, we evaluated whether the SDMs generated with pseudo‐absences are reliable and also if there are differences in the results obtained with profile and group discriminative techniques.Location Ecuador, South America.Methods The SDMs were generated with a training data set for each of the five species of Anthurium and six different methods: two profile techniques (BIOCLIM and Gower’s distance index), three group discriminative techniques [logistic multiple regression (LMR), multivariate adaptative regression splines (MARS) and Maxent] and a mixed modelling approach genetic algorithm for rule‐set production (GARP), which employs a combination of profile and group discriminative techniques and generates its own pseudo‐absences. For LMR, MARS and Maxent, three types of absences were generated: (1) random pseudo‐absences in equal number to presences and excluding a buffer area around presences (except for Maxent, which assumes that this background sample includes presences), (2) a large number (10,000) of random pseudo‐absences, also excluding a buffer area around each presence and (3) ‘target‐group absences’ (TGA), consisting of sites where other species of the group have been collected by the specialist, but not the species being modelled. To compare the predictive performance of the SDMs, the area under the curve statistic was calculated using an independent testing data set for each species.Results MARS, Maxent and LMR produce better results than the profile techniques. The models created with TGA are generally more accurate than those generated with pseudo‐absences.Main conclusions The advantages and disadvantages of different options for using pseudo‐absences and TGA with profile and group discriminative modelling techniques are explained and recommendations are made for the future.
1 June 2011 in Revista chilena de historia natural
En los últimos años se ha generalizado una nueva herramienta que permite analizar objetivamente los patrones espaciales de presencia de organismos: los modelos de distribución de especies. Estos modelos se basan en procedimientos estadísticos y cartográficos que partiendo de datos reales de presencia permiten inferir zonas potencialmente idóneas en función de sus características ambientales. Los datos de colecciones de historia natural pueden ser utilizados para este fin adquiriendo así una nueva utilidad. Los modelos han evolucionado desde su aplicación a especies aisladas hasta análisis de cientos o miles de taxones para combinarlos en el análisis de la biodiversidad y riqueza específica. En este trabajo se hace una revisión sobre la variedad de métodos utilizables, sus potencialidades e inconvenientes y los factores limitantes que influyen en la interpretación de lo que los modelos de distribución significan.
The extent to which species can balance out the loss of suitable habitats due to climate warming by shifting their ranges is an area of controversy. Here, we assess whether highly efficient wind-dispersed organisms like bryophytes can keep-up with projected shifts in their areas of suitable climate. Using a hybrid statistical-mechanistic approach accounting for spatial and temporal variations in both climatic and wind conditions, we simulate future migrations across Europe for 40 bryophyte species until 2050. The median ratios between predicted range loss vs expansion by 2050 across species and climate change scenarios range from 1.6 to 3.3 when only shifts in climatic suitability were considered, but increase to 34.7–96.8 when species dispersal abilities are added to our models. This highlights the importance of accounting for dispersal restrictions when projecting future distribution ranges and suggests that even highly dispersive organisms like bryophytes are not equipped to fully track the rates of ongoing climate change in the course of the next decades.
Species distribution models (SDMs) have proven valuable in filling gaps in our knowledge of species occurrences. However, despite their broad applicability, SDMs exhibit critical shortcomings due to limitations in species occurrence data. These limitations include, in particular, issues related to sample size, positional uncertainty, and sampling bias. In addition, it is widely recognised that the quality of SDMs as well as the approaches used to mitigate the impact of the aforementioned data limitations depend on species ecology. While numerous studies have evaluated the effects of these data limitations on SDM performance, a synthesis of their results is lacking. However, without a comprehensive understanding of their individual and combined effects, our ability to predict the influence of these issues on the quality of modelled species–environment associations remains largely uncertain, limiting the value of model outputs. In this paper, we review studies that have evaluated the effects of sample size, positional uncertainty, sampling bias, and species ecology on SDMs outputs. We build upon their findings to provide recommendations for the critical assessment of species data intended for use in SDMs.
About Me
Full-time Professor at the Universidad Autonoma de Madrid
Full-time Professor at the Universidad Autonoma de Madrid