New tool - Create Available Points Toolbox for ArcGIS

I have a new tool out that can be used to generate background/available points for habitat modeling (resource selection functions) in ArcMap.  It should work in ArcGIS Pro as well since it is entirely built within ModelBuilder and doesn't rely on any python. The user provides 1) their used points (e.g. occurrences), 2) a buffer from which available points can be selected, and 3) the ratio of used to available points. The tool will also combine multiple files into a single file using the filename to differentiate. This tool would be useful to wildlife biologists and others who work with radio-collar data and want a simple tool that runs in GIS. You can download the tool at https://www.arcgis.com/home/item.html?id=f5515ef257774ed790b9b64cf5d50fc5.
 

Adoption of monarch models by the Western Association of Fish & Wildlife Agencies

Great news.  The Western Association of Fish & Wildlife Agencies is now adopting our maps as part of the basis of their Draft Monarch Butterfly Conservation Management Plan. It is great to see western states taking the decline of this iconic species seriously and starting down the path of planning to help ensure their long-term survival.  You can view their news release by clicking HERE.

I'm excited to announce that our draft manuscript is underway and that we expect submission soon.

Western Monarch and Milkweed Mapper - a great tool for all citizen scientists

I'd encourage everyone to visit the Western Monarch and Milkweed Mapper to log your monarch and milkweed sightings.  The website is maintained by the Xerces Society, and the data contained withing it has been the primary source of data for our habitat mapping effort.

https://www.monarchmilkweedmapper.org
https://www.monarchmilkweedmapper.org/habitatsuitabilitymodels/

This morning I had the opportunity to join my daughter's second grade field trip to Betsy Donnelly Park where we spotted 3 narrowleaf milkweeds and 1 showy milkweed.  I logged them on the mapper.

There will probably be a huge rush of data as the professional scientists post their findings this fall, but it is really exciting and interesting to see monarch sightings in real time, so I'd encourage all of you citizen scientists and monarch lovers to post throughout the season.

Monarch butterfly and milkweed models the western U.S.

Today Matt Forister and I presented the results of our habitat modeling work for monarch butterflies and milkweeds for the western U.S. I've been involved in this research now since January 2017 and am very excited about having some preliminary maps and models ready. The work is an extension of the 2015 habitat modeling effort by Madeline Steele while she was at the U.S. Fish & Wildlife Service. Our work is a collaborative effort by University of Nevada Reno, the Xerces Society, the U.S. Fish & Wildlife Service, and others. I'm excited to get to work with such an iconic species, and I hope that through conservation and societal awareness of pesticides we can halt the decline of one of the most beautiful insect species in the world.

Upcoming Great Basin LCC Webinar on Pygmy Rabbit

Marjorie Matocq is presenting next Monday for the Great Basin Landscape Conservation Cooperative webinar series.  Sign up at http://greatbasinlcc.org/webinar-series .  If you can't make it there will be a recorded seminar available on YouTube in a couple of weeks.

New tool - Create Sampling Grid from Points for ArcGIS v. 1.0

With the advent of high-precision GPS spatially-explicit sampling designs have taken on an increasing importance in ecology and natural resource management. Spatially-explicit sampling regimes are useful for understanding processes such as attraction and repulsion that can be described using point pattern processes. This tool also opens up the possibility of random sampling within a larger grid. For example, users may want to collect field data to scale up to Landsat or MODIS pixels. It may be infeasible to collect data for an entire pixel, so some random sampling of the pixel may be necessary. Similarly there may be vegetation polygons or agricultural fields that the researcher wishes to sample in a random or a systematic manner. Finally, even if the researcher wishes to sample the entire grid having the ability to load center points or corner points onto a GPS and navigate to them may expedite field sampling. The creation of this tool was inspired by the needs of a current ongoing pygmy rabbit research project here in Nevada, Oregon, and Idaho.


This tool allows for the creation of polygons and centroids of polygons based on known points. The known points can be random locations, centroids of features of interest (e.g. polygons of agricultural fields or vegetation polygons), or regular gridded points across a landscape. This tool differs from existing tools, such as the Fishnet tools in ArcGIS, because it does not create a single grid for the entire landscape, but rather creates a local grid centered on each point in the input shapefile. It uses the following formula to achieve this:

(-1*(d/2) - 0.5) + i where d is the dimensions parameter and i is the iteration number. The two images below illustrate a grid with an even number of dimensions (6 on the left) and one with an odd number of dimensions (7 on the right). Both sampling grids are centered on points provided by the user, but the the one on the left has the original point (green) falling on a grid corner. The one on the right has the original point (provided by the user, in green) falling in the center of an individual grid tile.  The maroon points were created using the 'Feature Vertices to Points' tool, a standard ArcGIS tool with the advanced license.

Paper accepted in Ecological Applications

My paper entitled "Multi-scale connectivity and graph theory highlight critical areas for conservation under climate change" has been accepted in Ecological Applications pending a few minor revisions!  The general idea of this paper is to combine measures of habitat connectivity at the rangewide-scale, metapopulation scale, and local scale to inform conservation decisions. We use a combination of graph theory, Circuitscape, and least-cost paths to analyze the effect of different renewable energy development scenarios and climate change scenarios on habitat connectivity of the Mohave ground squirrel.  This paper follows from our earlier effort to map habitat suitability for Mohave ground squirrel:

Inman, R. D., Esque, T. C., Nussear, K. E., Leitner, P., Matocq, M. D., Weisberg, P. J., ... & Vandergast, A. G. (2013). Is there room for all of us? Renewable energy and Xerospermophilus mohavensis. Endangered Species Research, 20(1), 1-18.

as well as our earlier report to the California Energy Commission that included an analysis of climate change effects on habitat availability, landscape genetics, and a more limited analysis of renewable energy development scenarios titled "Habitat Modeling, Landscape Genetics, and Habitat Connectivity for the Mohave Ground Squirrel to Guide Renewable Energy Development" downloadable HERE .

In addition to demonstrating a multi-scale approach for assessing habitat connectivity and informing conservation decisions, the paper also presents a novel methodological contribution to make graph theory operational for species with continuously-distributed habitat.

Illustration by M. A. Walden

 

Common question - How to combine raster and vector data and deal with NoData

This one is probably the most common question I get.  It goes something along the line of  "I've got some polygon/line data that I want to combine with a raster layer, but how do I deal with the NoData outside the polygon?". Other situations that this apply to include other raster outputs that use NoData as their background, such as outputs from Brownian Bridges, or remote sensing images in which part of the image may be masked. Hence, nearly everyone who works with ArcMap in a natural resource context is likely to encounter this problem at least once (if not nearly daily in my case).

Here is a hypothetical example and solution. In the picture to the right we've got a habitat model (raster) and buffered roads which are not suitable habitat for our hypothetical species. We wish to combine the two layers to yield a habitat model in which all areas near roads are not suitable habitat (value = 0).

In ArcGIS the first step would be to convert the polygon to raster. We might do this using the Polygon to Raster Tool.  It doesn't matter what the Value Field is set to but you probably want to set the Cellsize to the same as the habitat model layer (see the picture to the right).

Then use the IsNull tool  to convert all areas that are NoData to 1.  The IsNull tool is in the Spatial Analyst toolbox and is also available as Map Algebra in the Raster Calculator tool. IsNull is a really simple, but also one of the most powerful tools in ArcMap.

The final step involves the use of the Con tool in Spatial Analyst to combine the IsNull output with the original raster (see below). The input conditional raster should be the output from the IsNull tool. The expression selects all cells with a value of 0 (i.e. in this case they are within the road buffer). The true value is set to 0 to indicate that areas near roads are unsuitable habitat. The false value uses the original habitat suitability raster to indicate that for area not near roads the habitat is the same as the habitat model.

The final result  is map that looks like the one below. Areas near roads all have a value set to zero. You can also combine IsNull and Con in raster calculator using the following type of statement: Con(IsNull[Raster],0,[Raster]) or use ModelBuilder to streamline the process.