Incorporating stressor trends into BD/CHI

[oharac]

Starting a new issue here because I think this is worthy of its own discussion. Given that one of the beauties of the CHI pace of change (POC - should have stuck with rate of change, or ROC) is, well, the pace of change of impacts on habitats, it would be cool to incorporate a pace of change of impacts on species in some meaningful way. The maps in issue #7 show the number of "impacted" species in any particular place - but no notion of the extent of impact (because no weighting of the "impact" of different stressors on a given species). So stressors are just present/absent and species are just present/absent.

I can calculate trends for individual stressors, just looking at the change in intensity in a cell over the 11-year span. But since we are ignoring the intensity of stressor in the species CHI (just focusing on the extent of the stressor's range), trying to quantify the effect of a change in the intensity of the stressor on the species doesn't make a ton of sense. Thoughts?

What I've done so far is to calc for each species its impacted range for each year - so we can look at increases/decreases in impacted range. I think this is a good start and in itself interesting, and adds more value to the same methodology as Allan et al. 2019 which (if I remember right) is just a snapshot of impacted area.

[bshalpern]

the last idea (trend in amount of range of each species that is impacted) is definitely super interesting and a great way to present results. This could be presented by trends in % of range from CHI and each individual stressor too, which would tell a more nuanced story. What is lost from this analysis but is something we can/will do for the OK project with UQ folks is the change in intensity of impact even when the extent doesn't change.  Given that is a key output of that project, we can/should leave it out of this current work.  There's plenty already that's included.

On 3/31/20 8:09 PM, oharac wrote: Starting a new issue here because I think this is worthy of its own discussion. Given that one of the beauties of the CHI pace of change (POC - should have stuck with rate of change, or ROC) is, well, the pace of change of impacts on habitats, it would be cool to incorporate a pace of change of impacts on species in some meaningful way. The maps in issue #7 <#7> show the number of "impacted" species in any particular place - but no notion of the extent of impact (because no weighting of the "impact" of different stressors on a given species). So stressors are just present/absent and species are just present/absent. I can calculate trends for individual stressors, just looking at the change in intensity in a cell over the 11-year span. But since we are ignoring the intensity of stressor in the species CHI (just focusing on the extent of the stressor's range), trying to quantify the effect of a change in the intensity of the stressor on the species doesn't make a ton of sense. Thoughts? What I've done so far is to calc for each species its impacted range for each year - so we can look at increases/decreases in impacted range. I think this is a good start and in itself interesting, and adds more value to the same methodology as Allan et al. 2019 which (if I remember right) is just a snapshot of impacted area. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#8>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABXMU62G4OOG2W5AJIP2VELRKKV67ANCNFSM4LYKZQGA>.

-- ********************************* Benjamin S. Halpern Director, Nat'l. Center for Ecol. Anal. & Synth. (NCEAS) University of California 735 State St., Suite 300, Santa Barbara, CA 93101 (ph) 805.893.7527 (web) http://www.nceas.ucsb.edu Professor, Bren School of Environmental Science and Management UCSB, Santa Barbara, CA 93106 Senior Fellow, UN Envir. Prog.- World Conserv. Monitor. Cent. (UNEP-WCMC) *********************************