The Changing Northern Range of the Japanese

Honeysuckle in Pennsylvania

Japanese Honeysuckle

Native to Japan and Korea

Introduced to the United States in the early 19th century

Popular ornamental plant at the time

Within a century it had spread to areas along the Potomac River

Can now be found throughout most of the southeastern United States

An Ecological Threat

The Japanese Honeysuckle:Is a perennial, semi-evergreen vineClimbs trees in order to increase sunlight exposureCan form dense mats on the forest floorCan also block entire sections of forest floor from receiving sunlight by forming these mats in tree canopiesCan strangle and even take down smaller treesHas few natural enemies

Pennsylvania’s Unique Geographical LocationLocated between 39˚ 43’ and 42˚ 16’ N

Climate similar to Northern Japan (Koppen)

Japanese Honeysuckle has invaded many southern Pennsylvania counties

Has been hindered by northern low winter temperatures

Can be found south of an isotherm where mean January temperature is 30˚F

Climate change will shift this isotherm

Also cannot grow in areas that receive less than 40 inches of rain, annually

Counties that have reported sightings of Japanese Honeysuckle within the past ten yearsSource: www.invasiveplantatlas.org

Climate ChangeGlobal temperatures and precipitation levels rising

This will lead to increased range of invasive species

Areas that currently are not suitable for Japanese Honeysuckle Growth will become suitable

IPCCThe Intergovernmental Panel on Climate Change has produced several climate change scenarios which project future environmental factors such as:

TemperaturePrecipitationCO2 concentration

Different projections based on different possible scenarios

Suitability ModelDesigned to help understand habitat distributions

Based on customizable input factors

Can be used to analyze change in these distributions

A very adaptable method of analysis

Can be raster or vector files

Data SourcesUnited States Department of Agriculture Geospatial Data Gateway

Data used: State, County outlinesNational Land Cover Dataset (NLCD)

WorldClim – Global Climate DataBioclim: current and future (IPCC) projected climatic raster datasets

Creating the Model

Created in ArcToolbox

Analysis uses spatial analyst tools

All analysis data converted into raster format and placed within a file geodatabase

Step 1:Import (and Reproject)

Import all raster data into model and ensure that they are all in the same projection

Input rasters include:Land UseCurrent TemperatureCurrent PrecipitationFuture TemperatureFuture Precipitation

Land Use Raster

Current Temperature and Precipitation

Rasters

Current Temperature (Left) and Precipitation (Right)

Future Temperature and Precipitation

Rasters

Future Temperature (Left) and Precipitation (Right)

Step 2:Reclassify

Reclassify rasters

This is a Boolean analysis, values that are not suitable for Japanese Honeysuckle growth are reclassified to the value 0, values that are suitable are reclassified to 1

Reclassify DetailsLand Use:

The Japanese Honeysuckle is capable of growing in most land use types with the exception of medium to high density urban areas or areas of open water

Current and future temperature:

Areas where temperature values are 30˚F or below will receive a 0. 31˚F and above receive a 1.

Current and future precipitation: Areas where precipitation values are 39” or below will receive a 0. 40” and above receive a 1.

Land Use Reclassified

Current Temperature and Precipitation

Reclassified

Current Reclassified Temperature (Left) and Precipitation (Right)

Future Temperature and Precipitation

Reclassified

Future Reclassified Temperature (Left) and Precipitation (Right)

Step 3:Combine

Combine raster files into two final layers, representing current and future habitat suitabilities

AttributesAt this point, the attribute tables look like this:

Step 4:Clip

Clip the two rasters to the study area

Overlay the counties file and put understandable color scheme on the data to get a sense of which areas are more suitable than others

Running the Model

After the suitability model is run, the geodatabase looks like this:

Current Suitability Output

Future Suitability Output