GREEN NEWS & VIEWS
Biodiversity ...continued from page 19
Status of Biodiversity 7KH ,3%(6SXEOLVKHG D VWXG\ RQ JOREDO ELRGLYHUVLW\ WKDW DV - sessed past, present, and potential future trends in biodiversity and HFRV\VWHPVHUYLFHV,QWKHVWXG\VFLHQWLVWVIRXQGWKDWVRFLHWDOH̆HFWV RQODQGIUHVKZDWHUDQGRFHDQVKDYHDFFHOHUDWHGLQWKHSDVW\HDUV and are contributing to an increase in the number of species threat- ened with extinction and the alteration of ecosystems and the services they provide to humans. Some scientists, however, argue that changes LQELRGLYHUVLW\DWWKHJOREDOVFDOHPD\QRWUHÀHFWFKDQJHVDWWKHORFDO scale, where biodiversity could be stable or increasing in some regions. %\DQDO\]LQJWKHSURSRUWLRQRINQRZQVSHFLHVFXUUHQWO\WKUHDWHQHG E\H[WLQFWLRQ VHHJUDSK WKH,3%(6H[WUDSRODWHGWKDWURXJKO\PLO - lion species—including both known and unknown species—could be WKUHDWHQHGZLWKH[WLQFWLRQ7KH,3%(6HVWLPDWHGWKDWRIQRQLQ - VHFWSODQWVDQGDQLPDOVDQGRILQVHFWVZKLFKDFFRXQWIRURI all species, could be threatened with extinction; it used 8.1 million as WKH HVWLPDWH RU WRWDO VSHFLHV 6RPH VWDNHKROGHUV FRQWHQG WKLV ¿JXUH PD\EHRYHULQÀDWHGEHFDXVHLWLVEDVHGRQDQLQÀDWHGHVWLPDWHRIWKH WRWDOQXPEHURIVSHFLHVRQ(DUWK2WKHUUHVHDUFKDOVRKDVTXDQWL¿HG currently threatened species and potential biodiversity loss, though WKHVH ¿QGLQJV KDYH YDULHG LQ H[WHQW DQG VHYHULW\ )RU H[DPSOH RQH VWXG\HVWLPDWHGWKDWQHDUO\RIZLOGSODQWVZHUHWKUHDWHQHGZLWK extinction. Another study estimated that some vertebrates’ population VL]HG KDG GHFOLQHG E\ DQ DYHUDJH RI RYHU WKH ODVW ¿YH GHFDGHV Further, a 2017 study concluded that, out of 177 mammal species stud- LHGPRUHWKDQKDGH[SHULHQFHG³VHYHUHSRSXODWLRQGHFOLQHV´ 7KH ,3%(6 DVVHVVPHQW DOVR UHSRUWHG WKDW HFRV\VWHPV¶ DELOLW\ WR provide services is declining. For example, the assessment stated that KXPDQ EHLQJV KDYH VHYHUHO\ DOWHUHG RI WKH ODQGEDVHG HQYLURQ - continued on page 87
Measuring Biodiversity How many species of plants, animals, fungi, and microorganisms exist on Earth is a fundamental, yet complex, question. As it is not currently possible to quantify every living species, scientists have used H[WUDSRODWLRQVWRHVWLPDWHWRWDOVSHFLHVULFKQHVV'XHWRGL̆HUHQWVFL - HQWLVWV¶GL̆HUHQWPHWKRGVDQGDVVXPSWLRQVHVWLPDWHVIRUWKHQXPEHU of species on Earth have varied, sometimes widely. To date, scientists KDYH GLUHFWO\ GHVFULEHG DSSUR[LPDWHO\ PLOOLRQ VSHFLHV0DQ\ HV - WLPDWHVSODFHWKHDFWXDOQXPEHURIVSHFLHVEHWZHHQPLOOLRQDQG PLOOLRQ WKRXJK HVWLPDWHVKDYH UDQJHG IURP EHORZ PLOOLRQ WR RYHU 100 million species. In addition to assessing species diversity, biodiversity often incor- SRUDWHVFRQFHSWVRIJHQHWLFDQGHFRV\VWHPGLYHUVLW\*HQHWLFGLYHUVLW\ is a measure of genetic variation among individuals of the same spe- cies. Ecosystem diversity is a measure of the variety of ecosystems, de- ¿QHGDVWKHFRPPXQLW\RIRUJDQLVPVDQGWKHLUSK\VLFDOHQYLURQPHQWV interacting together, in a given location. Changes in Biodiversity The number of species on Earth is not static, and extinctions and speciation constantly occur through natural processes. Humans also LQÀXHQFH ELRGLYHUVLW\ DQG PDQ\ VFLHQWLVWV DVVHUW WKDW ELRGLYHUVLW\ is currently being lost at a rate unprecedented over human history. Some counter this assertion by arguing that extinction is part of evo- lution and that all species are somewhere on the road to extinction; WKH\QRWHWKDWWKHUHKDYHEHHQ¿YHPDVVH[WLQFWLRQVLQ(DUWK¶VKLVWRU\ without anthropogenic pressure.
28—PATHWAYS—Fall 21
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