Researchers from the King Juan Carlos University (URJC) have carried out a research study published in Biological Conservation, which looked at whether spiders were more tolerant of human impact than other animals. The answer was no: arachnids suffer the consequences of changes to their landscape just like any other animal.
"The abundance and number of spider species is negatively affected by the impact of many human land uses, such as habitat fragmentation, fire and pesticides", Samuel Prieto-Bentez and Marcos Mndez, researchers at the URJC Biodiversity and Conservation Department, tell SINC.
Given the "scarcity" of threatened spiders on the Red Lists, which are very in vogue at the moment, the researchers tried to find out whether spiders are exempt from the risks caused by human action, by means of a meta-study of a total of 173 scientific papers published since 1980, which provide more generalizable data.
"The technique used meant we could rigorously combine the results of a lot of studies. This is regularly used in medicine in order to arrive at general conclusions about the effects of drugs, based on numerous trials with more limited coverage", say Prieto-Bentez and Mndez, who studied the human impact in three ecosystems: farmland, pasture and woodland.
Until now, fewer than 20% of studies had indicated any negative effects of human impact on arachnids. The study, which has been published in Biological Conservation, demonstrates "evident" damaging effects on spider numbers due to the use of soil in farming and pasture systems. "In woodlands this was not so clear", the study explains.
In farming and pasture ecosystems all over world, fires, sheep-grazing and conventional crops have a harmful effect on arachnid fauna because they cause extreme changes to the vegetation structure. Spider abundance is affected in woodland by habitat fragmentation.
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