8 - Community interactions

L86 bio 3115 universit dottawa university of ottawa

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Unformatted text preview: University of Ottawa M8..3 BIO 3115 Conservation Biology 3/11/2014 A Canadian habitat modifier: the beaver L8.7 Bio 3115 Université d’Ottawa / University of Ottawa Some keystone species: food sources Figs, while having relatively low density, are important food sources for frugivores during the dry season. So, declines in fig pollinators (fig wasps) can result in dramatic changes in bird/primate community. Pollination Fig production and consumption Fig trees/vines (< 1% forest biomass) L8.8 Bio 3115 Université d’Ottawa / University of Ottawa M8..4 BIO 3115 Conservation Biology 3/11/2014 Classes of keystone species and the effects of their loss K eysto n e class E ffect o f lo ss to p carn ivo res in crease in ab u n d an ce o f p rey; o verg razin g larg e h erb ivo res h ab itat su ccessio n an d d ecrease in h ab itat d iversity h ab itat m o d ifiers d isap p earan ce o f h ab itat featu res S eed d isp ersers recru itm en t failu re o f certain p lan ts so il red u ced n u trien t cyclin g , m icro b es/d eco m p o sers in creased leakag e /d etritivo res m u tu alistic fu n g i tree d ieb ack P arasites, p ath o g en s E xp lo sio n o f h o st sp ecies L8.9 Bio 3115 Université d’Ottawa / University of Ottawa Some problems with the keystone concept just who (or what) is a keystone species is often difficult to predict. focus on “keystone” species may result in loss of several nonkeystone species whose cumulative effects may well be greater than the loss of a keystone species. Community impact of loss Keystone species? Keystone S1+ S2 S1 S2 Species L8.10 Bio 3115 Université d’Ottawa / University of Ottawa M8..5 BIO 3115 Conservation Biology 3/11/2014 Exotic/invasive species Exotic (alien) species are those not native to the geographical area in question; introduced beyond native range; Exotic invasive species are those which, when introduced into new habitats, have the potential to rapidly increase population size/density. L8.11 Bio 3115 Université d’Ottawa / Univers...
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