Advice on spatial scale mismatch: Landscape covariates for 10x10km grid vs averaged point-level buffers
I am a PhD student currently working on modeling the spatial distribution of several bird species in Morocco using opportunistic presence/absence data (eBird checklists). I am preparing to run Generalized Linear Mixed Models (GLMMs) using packages like lme4 or glmmTMB, and I am facing a methodological dilemma regarding the extraction scale of my environmental and landscape variables. *The Data:* - My study area is divided into a 10x10 km grid. - I have calculated the probability of occurrence (presence/absence) at the scale of these 100 km? cells. - The observation points (checklists) are often spatially biased (clustered near roads, villages, etc.). *The Dilemma:* To extract my landscape covariates (e.g., land cover percentages, NDVI) to include as fixed effects in my GLMM, I am hesitating between two approaches: 1. *Whole-cell extraction:* Calculating the landscape variables across the entire extent of the 10x10 km cell to match the spatial unit of the response variable. 2. *Averaged point-buffers:* Creating a buffer (e.g., 1 km radius) around each specific checklist point within the cell, extracting the landscape data for these buffers, and then averaging these values to assign a single mean value to the 10x10 km cell. My current understanding is that approach #2 might introduce a spatial scale mismatch and suffer from observer bias (modeling the "landscape of the observer" rather than the available habitat in the cell). Therefore, approach #1 seems statistically and ecologically more robust for a response variable modeled at the cell level. Could anyone share their experience or confirm if approach #1 is the standard best practice in this context? Any recommended literature specifically addressing this scale matching in GLMMs using opportunistic data would also be highly appreciated. Thank you very much for your time and insights. Best regards, -- *Mohamed EL Mekkaoui* *Doctorant - Chercheur* *Laboratoire de Biodiversit?, ?cologie et G?nome (* BGCG*)* Facult? des Sciences, Universit? Mohammed V de Rabat *LinkedIn :* <http://goog_85098632>linkedin.com/in/mohamed-el-mekkaoui *Email :* mohamedelmekkaoui98 at gmail.com *T?l :* +212 7 08 00 50 71 -- --------------------------------------------------------------------------- ????? ??????? ?????? ?????????: ??? ???????? ??? ?? ??? ????????? ???? ?????? ????????? ?? ??? ????? ?? ????? ?????? ????? ???. ??? ?? ??? ?????? ???? ???????? ???? ????? ?????? ????? ??????? ???? ???? ????? ?? ??????? ????????? ?? ?????. ?? ??????? ??? ???? ?? ?????. ?????? ??????? ?? ??? ??????? ?? ???? ?????? ??? ??? ???? ???????? ????? ?? ???? ????? ???? ?????? ???????. ??? ??????? ?? ??????? ??? ??? ????? ???????? ????? ??????? ?? ????? ?? ?????. ?? ????? ????? ???? ?????? ??????? ?? ??????? ?? ?? ????? ?? ????? ?? ???????. ???? ?????? ?????????? ??????? ????? ???? ????????? ??????? ??? ?????? ??????????. --------------------------------------------------------------------------- Avis de confidentialit?, clause de non-responsabilit? et avis de s?curit? : Ce message, y compris ses pi?ces jointes, est confidentiel et destin? uniquement au destinataire pr?vu. Si vous n??tes pas le destinataire, veuillez en informer l?exp?diteur et supprimer toutes les copies. Toute utilisation non autoris?e est interdite. Les opinions exprim?es n?engagent que l?exp?diteur et ne refl?tent pas n?cessairement la position de l?Universit? Mohammed V de Rabat. Ce message est ? titre informatif uniquement et ne constitue pas un conseil professionnel. L?Universit? Mohammed V de Rabat d?cline toute responsabilit? pour les erreurs ou alt?rations du message. Nous vous conseillons de prendre les pr?cautions n?cessaires pour s?curiser les informations transmises. --------------------------------------------------------------------------- Confidentiality notice, disclaimer, and security notice: This message, including any attachments, is confidential and intended solely for the recipient. If you are not the intended recipient, please notify the sender immediately and delete all copies from your system. Any unauthorized use is prohibited. The opinions expressed in this email are those of the sender and do not necessarily reflect the official position of Mohammed V University in Rabat. This message is for informational purposes only and should not be construed as legal, financial, or professional advice. Mohammed V University in Rabat does not accept any responsibility for errors or alterations to the message. We recommend taking the necessary precautions to ensure the security of the information transmitted via email. -- *Mohamed EL Mekkaoui* *Doctorant - Chercheur* *Laboratoire de Biodiversit?, ?cologie et G?nome (* BGCG*)* Facult? des Sciences, Universit? Mohammed V de Rabat *LinkedIn :* <http://goog_85098632>linkedin.com/in/mohamed-el-mekkaoui *Email :* mohamedelmekkaoui98 at gmail.com *T?l :* +212 7 08 00 50 71
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