Koustubh Sharma Profile picture
Director-Science and Conservation @snowleopards | Intl Coordinator @gslep_program | Wildlife conservation | Science | data viz | Technology | Amateur Astronomy

Oct 3, 2022, 16 tweets

Do you use #CameraTraps for wildlife abundance? Do you feel intimidated by the complex models & codes that statisticians come up with to help design & analyze camera trap data?
If your answer is yes to any of the above, follow this thread with a new resource that is pure gold:

Spatial Capture Recapture (#SCR) co-developer @david_borchers and fellow @indurbach with @statsStAndrews have created a fabulous website with online training material to help get started with spatial capture-recapture (SCR) methods, with a focus on camera traps.

With simple, intuitive navigation, the site has three sections:
1. Software
2. Training videos
3. Other resources
While there are a few books on #SCR, remember the method has undergone rapid development during the last decade, making it daunting to keep pace...

For newbies, the site provides a series of links to download the software one would need to run #SCR models. Find guidance to download #Rstats, #Rstudio & package 'secr'. Additionally, there are links to two brilliant resources on how to navigate through R & RStudio

Now the main course! Divided into 6 chapters and 15 sub-sections, it packs a formidable 138 minutes of high-value content and hand-holding on planning, designing, modeling detectability and density, and data setup and analysis for #SCR with #cameratraps

Chapter 1: Pre-design planning introduces the viewer to important concepts behind survey design decisions
You learn about:
1. Design-based inference for abundance
2. Stratified sampling for better design-based inferences
3. Model-based inference for abundance, using covariates

Chapter 2: Micro-level design to learn to place camera traps for a single survey:
1. Foundations of SCR survey design, including precision & bias, and the importance of sample size
2. Examples of good & bad designs: illustrating "hero" (good) and "villain" (bad) designs (contd)

Chapter 2 (contd):​
3. Software for creating and testing potential SCR survey designs
4. New developments in SCR survey design to look at some newer, more advanced approaches to survey design.

Chapter 3: Macro-level survey design when surveying very large regions.
Describes:
1. Foundations of what macro-level design is, why spatial balance is important, and how to achieve this using Halton points
2. Software that selects Halton points for macro-level survey regions

Chapter 4: Modelling animal encounter rates that address detectability.
1. Encounter functions to answer how often do we expect a camera to detect an animal?
2. Encounter function design issues to learn about the link between encounter rate modeling and camera trap placement.

Chapter 5: Modelling animal density, given imperfect detectability
​1. Kinds of density models to determine where animals have their activity centers
2. Density models' design issues where we learn about the link between density modeling and camera trap placement

Chapter 6: Fitting models using package secr in R
1. Data setup describes some of the basic options for setting up data for analysis with secr
​2. Fitting models to learn about estimating the parameters of the SCR model and draw inferences about animal density and detectability

The section 'Other resources', provides links to:
1. Training material created by @gslep_program & @SnowLeopardNet for the #PAWS initiative
2. Quick-reference "cheatsheets" for data analysis with secr
3. Link to the formidable Google Group on #SCR curated by Murray Efford

Need further assistance getting started with #SCR and #CameraTrap design and analysis? The site allows you to reach out to experts for direct assistance.
Having worked closely with both David and Ian, I can attest that they are the #GOAT when it comes to population ecology

Reliable, replicable assessments of biodiversity are the cornerstone of effective conservation and monitoring programs.
This goldmine on designing and analysing #CameraTrap data can be accessed here: scr-cameratrap.com
Please like and retweet widely 🙏🏽

Although much of the resources here were developed for #SnowLeopards, the guidance is species agnostic as long as animals can be identified as individuals.
Kudos @EPSRC @snowleopards @SLF_Pak @Cape_Leopard, & @PantheraCats for supporting the development of this #SCR goldmine!

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