Does the choice of climate baseline matter in ecological niche modelling?

Ecological niche models (ENMs) have multiple applications in ecology, evolution and conservation planning. They relate the known locations of a species to characteristics of its environment (usually climate) over its geographical range. Most ENMs are trained using standard 30-year (1961-1990) or 50-year (1951-2000) baselines to represent current climate conditions. Species occurrence records used as input to the models, however, are frequently collected from time periods that differ from those from which the climate is derived. Since climate variability can be significant within and outside baselines, and the distributions of some plants and animals (e.g., annual plants, insects) can adjust to environmental conditions on much shorter time scales, this mismatch between collection records and climatic baselines may affect the utility and accuracy of model outputs. We investigated how the choice of baseline periods influenced modelling efforts, anticipating that climate baselines derived from the same temporal period as the species records would yield improved ENMs. Ten simulated species’ distributions were modelled using an ENM (Maxent) for (a) occurrences and climates within the same temporal period, based on eighteen 10-year baselines within the 20th century and (b) all available samples and climate baselines from 1951-2000 and 1961-1990. Each model was projected onto all the available 10-year climate scenarios and compared to the models trained on the corresponding scenario. We show that temporal mismatches of species occurrences and climate baselines can result in significantly poorer distribution models. Such temporal mismatch may be unavoidable for many studies, but we emphasize here the need to match the time range of samples and climate data whenever possible.     

How should surface elevation table data be analyzed? A comparison of several commonly used analysis methods and one newly proposed approach

Environmental and Ecological Statistics - The use of surface elevation table (SET) instruments to monitor elevation changes at low elevation coastal locations has steadily increased in recent...     

A dynamic size-structured population model: does disturbance control size structure of a population of the massive coral Gardineroseris planulata in the Eastern Pacific?

Using a long-term data set of Gardineroseris planulata (Dana) on Uva Island reef, Panamá, we developed a simulation model that relates size-specific schedules of growth and partial mortality to predation by Acanthaster planci (Linnaeus) and El Niño–Southern Oscillation (ENSO)-related elevation of water temperature. We compared the model predictions to field observations for both the subpopulation of colonies that was used for model development and for the entire population. No statistically significant differences in the size-frequency distributions of the real and modeled coral populations were found for the subpopulation during any of 9 yr or for the entire population during 4 yr. These results suggested that the model relationships were reflecting field conditions. Longer-term (100 yr) simulations were conducted to assess the relative importance of predation and ENSO-related colony losses in determining the size structure of the coral population. Predation by A. planci was of overwhelming importance due to both stronger effects of predation (larger transitions) and the frequency of predation (yearly) compared to ENSO (episodically). Even the least-frequent predation scenario skewed the distribution toward smaller colonies, while simulations where populations were subjected to frequent ENSO events (≥3 yr) still maintained colonies in the largest size class. The model results suggested that sea star predators may not have been in the present abundance on this reef prior to the last 30 yr; with predators present, the model predicts that the distribution would be skewed toward smaller colonies.     

Why does environmental compliance cost more than penalty? —A legal analysis on environmental acts of enterprises in China

In the environmental protection field of China, due to lower law-breaking cost but higher law-abiding cost , it is a common case that the enterprise chooses to break through the law on purpose. The punishment to the unlawful pr