What is the Landscape Resilience Index?

The International Panel on Climate Change defines resilience as the ability of a social or ecological system to absorb disturbances while retaining the same basic structure and ways of functioning (IPCC 2007). The features of a landscape can enhance the resilience of species and ecosystems by providing access to relatively cool areas during extended heat waves and surface water during drought. While there are many features of the landscape that can provide refuge, we focus on the ones than can be mapped and are likely to endure for hundred of years. These features include the moderating effect of the ocean (Coastal Proximity), a diversity of climatic types in a small area (Elevation Gradients and Topographic Diversity), proximity to dependable water (Distance to Water), and rivers that connect low and high elevations (Riparian Corridors). The Landscape Resilience Index combines these 5 features with equal weighting to generate an index where 0 represents an area with the lowest resilience and 100 represents an area with the highest resilience.  You can download a poster sized map of the landscape resilience index with a full description of the input data and methods.

How should I use this information?

The Landscape Resilience Index is designed to be used at a large scale such as the state or an ecoregion. It provides a simple metric for comparing landscape scale projects and to support initial thinking on climate change adaptive strategy development. However, the Landscape Resilience Index can not tell you where to engage and how. It is designed to be one element to consider in a longer climate change adaptation planning process. In general, this process involves setting goals, determining target species and systems, projecting the climate change impacts to those target species and systems, and developing strategies to help abate those impacts.

What features did you include and why?

The Landscape Resilience Index is the summation of the following five equally weighted factors:

• Coastal Proximity. The ocean heats and cools slower than the land, so as air flows from the ocean over land it tends to moderate the coastal climate. Coastal proximity was calculated as described in a recent climate publication (Daly, Halbleib et al. 2008) using an advection model that incorporates the prevailing wind patterns and minimizes the number of mountains and the distance air must traverse as it flows from the ocean to the land.

• Elevation Gradients. Elevation has a direct affect on temperatures and often influences precipitation patters. A diversity of elevations in a small area will give species access to different climatic zones as climate changes. We calculated the elevation range in a 10-kilometer moving window using the ~30-meter National Elevation Dataset(U.S. Geological Survey 2008).

• Topographic Diversity. North facing slopes receive less solar radiation during the day and tend to be cooler and have more soil moisture than their south facing counterparts. Areas with a diversity of slopes and aspects will provide a diversity of micro-climates for species as the climate changes. We calculated the incoming solar radiation using the ~30-meter National Elevation Dataset (U.S. Geological Survey 2008) and ArcGIS. We then calculated the range in solar radiation values in each ~800-meter grid cell.

• Distance to Water. Droughts may become more frequent and severe as the climate changes, so species will need reliable sources of fresh water to survive. We identified all of the seeps and springs and large perennial water bodies (>100 hectares) as the water sources that are most likely to persist even in a drought. We calculated the straight-line distance to these water sources as mapped in the National Hydrology Dataset (U.S. Geological Survey 2009) using ArcGIS.

• Riparian Corridors. Rivers provide low gradient habitat connections for many species between different climate zones. In addition, riparian vegetation tends to be more dense than the surrounding vegetation and provides ample shade on hot days. To map riparian corridors, we calculated the maximum elevation in each stream system and then subtracted the lowest elevation that stream system flows to (either the ocean or a landlocked lake or salt flat) using the National Hydrology Dataset (U.S. Geological Survey 2009).

What do I do if my project is in a red zone (an area with low resilience)?

First, don’t panic! The Landscape Resilience Index is just one piece of information to consider in the climate change adaptation planning process and there are plenty of reasons why we need to engage in areas of low resilience. However, if you do work in an area of low resilience, some things you should consider while you proceed with the climate change adaptation planning process is how you could increase the resiliency for the key species and ecosystems at your site. This might include restoration of riparian vegetation to increase shading and reduce stream temperatures during the hottest times of year. You may also consider increasing the connectivity within and around your site so that species that can move can get to areas of higher resilience during heat waves and droughts. These are just a few examples of the type of conservation strategies that will emerge from a more detailed climate change adaptation planning process.

What does it mean if my project is in a blue zone (an area with high resilience)?

This means that the landscape of your project may enhance the resilience to climate change for some of the species found there. However, it does not mean that all the species will have no trouble adapting to climate change. In particular, species with narrow climate tolerances and low dispersal ability may still be stressed by climate change and may not be able to access the refugia provided by north facing slopes and seeps and springs. Other species may be dependent on other landscape features such as mountain meadows or rare soils so they can not move to other areas offering more resilience.

Where can I get more information?

If you would like to know more about the Landscape Resilience Index, please email Kirk Klausmeyer (kklausmeyer@tnc.org).

Sources: 

Daly, C., M.Halbleib, et al. (2008). "Physiographically sensitive mapping of climatological temperature and precipitation across the conterminous United States." International Journal of Climatology 28 (15): 2031-2064.

IPCC (2007). Climate Change 2007: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge, UK, Cambridge University Press.

U.S. Geological Survey (2008). National Elevation Dataset (NED) 1 Arc Second.

U.S. Geological Survey (2009). National Hydrology Dataset. The National Map.