WIKIMEDIA, OLIVER HEROLD
1. Dialing back extinction rates
A widely-used, indirect method of estimating how quickly species will vanish based on how much of their habitat is lost likely overestimates actual extinction rates. Calculating the loss of species based on habitat shrinkage usually misjudges extinction rates because the area required to remove the last individual of a species is almost always much larger than the area needed to encounter the first individual.
Increasing the flow of energy through ecosystems makes them less stable by increasing the ratio of consumers to resources available. And it turns out that watery ecosystems are more vulnerable to this instability than terrestrial systems as populations of small-bodied, aquatic organisms experience greater population variability when energy flux increases.
The habitat ranges of birds, mammals, fish, plants, and arthropods are shifting to higher latitudes and altitudes at rates two to three times faster than previously estimated due to warming temperatures.
Generalist populations often harbor individuals that are more specialized, especially in the diet they consume, than their neighbors. How many individuals diverge from their population's typical diet depends on the level of intra and interspecific competition, ecological opportunity, and predation.
The fungus-growing ant species, Mycocepurus smithii, was long thought to be exclusively asexual, as only parthenogenetic populations had been collected from widely separated areas. But researchers have found that sexually-reproducing populations cluster along the Rio Amazonas and the Rio Negro in South America.
C. Rabeling, et al., "From the Cover: Cryptic sexual populations account for genetic diversity and ecological success in a widely distributed, asexual fungus-growing ant," Proc Natl Acad Sci USA, 108:12366-71, 2011. Free F1000 Evaluation
This 35-year-old paper is still the standard proof that well-developed, well-connected, and species-rich community structures lead to more stable ecosystems.
Using an algorithm that calculates species numbers based on patterns of the higher taxonomic classification of species to phyla, classes, orders, etc., researchers estimate that more than 8.5 million eukaryotic species, more than 2 million of which are marine organisms, exist on planet Earth. If the estimation is correct, this would mean that about 86 percent of terrestrial species and 91 percent of ocean-dwelling organisms await discovery and description.
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