Biotic and anthropogenic forces rival climatic/abiotic factors in determining global plant population growth and fitness
Data files
Dec 13, 2019 version files 614.69 KB
Abstract
Multiple, simultaneous environmental changes, in climatic/abiotic factors, in interacting species, and in direct human influences, are impacting natural populations and thus biodiversity, ecosystem services, and evolutionary trajectories. Determining whether the magnitudes of the population impacts of abiotic, biotic, and anthropogenic drivers differ, accounting for their direct effects and effects mediated through other drivers, would allow us to better predict population fates and design mitigation strategies. We compiled 644 paired values of the population growth rate (lambda) from high and low levels of an identified driver from demographic studies of terrestrial plants. Among abiotic drivers, natural disturbance (not climate), and among biotic drivers, interactions with neighboring plants had the strongest effects on lambda. However, when drivers were combined into the three main types, their average effects on lambda did not differ. For the subset of studies that measured both the average and variability of the driver, lambda was more sensitive to one standard deviation of change in abiotic drivers relative to biotic drivers, but sensitivity to biotic drivers was still substantial. Similar impact magnitudes for abiotic/biotic/anthropogenic drivers holds for plants of different growth forms, for different latitudinal zones, and for biomes characterized by harsher or milder abiotic conditions, suggesting that all three drivers have equivalent impacts across a variety of contexts. Thus the best available information about the integrated effects of drivers on all demographic rates provides no justification for ignoring drivers of any of these three types when projecting ecological and evolutionary responses of populations and of biodiversity to environmental changes.
Methods
The main data consist of pairs of estimates of population growth rates of terrestrial plants, one from a relatively high and one from a relatively low level of an identified environmental driver (i.e., a factor such as climate, soil, interactions with competitors, herbivores, pathogens, or pollinators, or anthropogenic impacts). These estimates were taken from published studies. When available, levels of the environmental driver are also included, along with meta-data from each site (e.g., publication citation, species name, geographical location, etc.).
Dataset S1 includes the full data extracted from the data sources; see <Raw lambda estimates.xlsx>
Dataset S2 includes all data used in the statistical analyses, based on the full data from Dataset S1; see <Data for analysis.xlxs>
The file <Source references.pdf> gives the full citations for the papers in Datasets S1 and S2.
Usage notes
The datasets are in the form of an Excel file. The second worksheet in each file describes what each column in the first datasheet represents.