new paper - Adaptive divergence despite low effective population size in a peripherally isolated population of the pygmy rabbit, Brachylagus idahoensis in Molecular Ecology

 Nathan Byer is the lead author on our new landscape genomics paper on pygmy rabbits.  The paper is published in Molecular Ecology and is somewhat of a companion to a hopefully forthcoming landscape genetics paper on pygmy rabbits.  You can view the paper by clicking HERE.

new paper - Phenology-based classification of invasive annual grasses to the species level

The Great Basin Landscape Ecology Lab and Center for Transformative Environmental Monitoring Programs has a new paper in Remote Sensing of Environment that uses drones to map two different invasive grasses in the Great Basin - cheatgrass and medusahead.  Our study found that we could effectively differentiate the species using three well-timed flights and a simple red-green-blue camera.  Using unmanned aerial vehicles we were able to accurately map the occurrence of these two different invasive species on the landscape. You can read our paper by clicking HERE.

New tool - Count Coincident Lines

I have a new ArcGIS geoprocessing tool out called  Count Coincident Lines on ArcGIS Online or by clicking HERE.

Sometimes we want to know the number of coincident line features in a feature class. For example, perhaps we are interested in the movement of organisms on a landscape and we have multiple least-cost path lines that we are interested in depicting using varying line widths or colors.

 

 

 

 

 

Figure 1: Lines are overlapping so it isn’t possible to depict which segments are coincident with others.

 

 

 

 

 

Figure 2: Line widths depict the number of coincident lines.

Parameters

The tool has only four parameters and does not create any intermediate files.

Input Lines  - The input lines parameter should have multiple coincident line features and should have a projected coordinate system.

Coordinate system – This is the native coordinate system of the input lines. (Right click on the layer – Properties – Source - Projected Coordinate System).

Length unit – The native length unit of the input lines (Right click on the layer – Properties – Source – Linear Unit).

Output Lines – Output line shapefile or geodatabase feature class.

 

 

 

 

 

Figure 3: Dialog for the Count Coincident Lines tool.

Model

The model consists of four simple steps and uses tools that only require a Basic ArcGIS license. The first step uses the Add Geometry Attributes tool to add the START_X, START_Y, MID_X, MID_Y, END_X, END_Y. These are reserved fields and should not be present in the input lines.

Next, the model adds a field called COUNT (also a reserved field)  and calculates count such that each line segment has a values of 1.

Finally, the tool dissolves based on the START_X, START_Y, MID_X, MID_Y, END_X, END_Y assuming that lines with these six values in common are coincident.  There may be circumstances where this assumption is violated so please think carefully about whether this is true for your data or not.

The number coincident segments per line is shown in the COUNT_COUNT field (also reserved) and can be depicted on a map like in Figure 2.

 

 

Figure 4: Count Coincident Lines tool as viewed from Model Builder (right click - edit).

Citation

Dilts, T.E. (2020) Count Coincident Lines Toolbox for ArcGIS. University of Nevada Reno. Available at: https://www.arcgis.com/home/item.html?id=6b0d7669d7ea4cc3b62ecddea209c251

ArcGIS Idea - Extract Multivalues to Polygons

ArcGIS would be much more friendly if it had a tool called "Extract Multivalues to Polygons" that saved users some joining steps.  See my idea - HERE

Paul Burow's work featured on the Mountain West News Bureau and NPR

Congratulations Paul Burow on having your research featured on NPR! This is really interesting stuff.  You can view the NPR news story at this link:

https://www.kunr.org/post/rural-westerners-may-be-changing-their-minds-about-government

The project website is at this link:

http://covidruralwest.org/ 

Paul is a PhD Candidate at Yale University in the School of the Environment and Department of Anthropology, but he lives in Reno, and participates in lab meetings of the Great Basin Landscape Ecology Lab. We are very lucky to have him, as he is always very thoughtful, broadens our discussions, and brings a new perspective to the discussions.  Thank you Paul.

Work featured in National Geographic article

I'm excited to see that our article in the journal Water titled "Rapidly Accelerating Deforestation in Cambodia’s Mekong River Basin: A Comparative Analysis of Spatial Patterns and Drivers" is getting some press.  It was recently featured in the National Geographic article by Stefan Lovgren "Cambodia’s biggest lake is running dry, taking forests and fish with it". In fact, the main figures are derived from our data!  Deforestation in Cambodia is among the very highest in the world, and our results show that the rate of deforestation is rapidly accelerating. This is especially concerning given the large number of species that are right on the brink of extinction already.  It is likely that without more intervention that many endangered species in Cambodia will go extinct. Stefan's article does a wonderful job of highlighting the role of flooded forest around the Tonle Sap, southeast Asia's largest inland lake, and the fact that it is rapidly being lost due to forest clearing increased wildfire. My hope is that Stefan's article will help wake people to the severity of the situation and help them realize what could be lost if we fail to take conservation action.

 The Wonders of the Mekong is a multidisciplinary collaborative project funded by USAID since 2016. Based in Cambodia, the project aims to maintain the ecological, cultural, and economic integrity of the vital Mekong river system through interdisciplinary research, capacity building, and education and outreach. More about the project can be found on Facebook (https://www.facebook.com/MekongWonders/), Instagram (https://www.instagram.com/mekongwonders/) and YouTube (https://www.youtube.com/mekongwonders).

Congratulations Sapana Lohani and team on the publication in the journal Water

Congratulations Sapani Lohani, Peter Weisberg, Sarah Null, and Zeb Hogan on a job well done!  Our paper "Rapidly Accelerating Deforestation in Cambodia’s Mekong River Basin: A Comparative Analysis of Spatial Patterns and Drivers" was just published today online in the journal Water, and you can view it by clicking HERE.  I'm really proud of the job that we did. This paper is part of a special edition in the journal Water that features a wide range of topics about the Lower Mekong. You can view the other papers in the special edition by clicking HERE. All of the papers in Water are open access so I'd encourage you to download them and read them.

Our analysis covered a time period from 1993 to 2017 and saw an accelerating rate of deforestation in Cambodia. This is notable because many tropical countries have seen a slowing of their deforestation rate (such as Brazil). In Cambodia, on the other hand, deforestation rates appear not just to be increasing, but to be rapidly accelerating. This has potential to lead to extinctions of forest-dependent species and may already be having an impact on nutrient cycling in aquatic systems. In our paper we studied four different geographic regions - the entire nation of Cambodia, Cambodia + Srepok, Sesan, and Sekong River Basins extending into Laos and Vietnam, just the Srepok, Sesan, and Sekong River Basin, and the area around the Tonle Sap Lake. We also examined forest loss in protected areas and community forests. We hope that our results will wake the world to the tremendous biodiversity loss that is occurring in this region and encourage land managers and policy makers to take stricter actions to reverse the loss of forests in this region.

The Wonders of the Mekong is a multidisciplinary collaborative project funded by USAID since 2016. Based in Cambodia, the project aims to maintain the ecological, cultural, and economic integrity of the vital Mekong river system through interdisciplinary research, capacity building, and education and outreach. More about the project can be found on Facebook (https://www.facebook.com/MekongWonders/), Instagram (https://www.instagram.com/mekongwonders/) and YouTube (https://www.youtube.com/mekongwonders).