Photography for Invasive Species Occurrences
A key component of EDDMapS is providing images in digital format. Being able to use photographs to identify the species adds validity to the data collected and entered into EDDMapS. This module addresses general photography topics, including types of photographs, tips for taking quality photographs, and an introduction to digital photography. Information on uploading images is addressed in the "How To EDDMapS" section.
Identification
Nearly all field guides and identification keys rely on illustrations
because seeing a picture or drawing of an organism greatly aids in the
correct identification. These pictures may be
of the whole organism or simply a specific
characteristic or feature important for
distinguishing that organism.
For instance, a picture of an exotic plant infesting a natural area can help demonstrate the invasive potential of that plant. This type of picture can lend credibility to statements made by the photographer or user of the image. Familiarize yourself with the characteristics commonly needed for identification like the glandular notches of tree-of-heaven and take several pictures of the subject's diagnostic characteristics to ensure that identification is possible. Good photographs can also add validity to documentation of certain events, such as the first occurrence of a species in a county. Herbarium records have the highest validity, so consider collecting an herbarium specimen for the first reported occurrence of an invasive species in a region or county.
The following section briefly explains basic techniques and gives tips for taking useful photographs. To fully understand your camera's options, refer to the user manual.
Framing
Frame the subject for the intended purpose. Panoramic photographs give context to the subject, for example showing the extent of an infestation. Midrange shots illustrate the presence and effects of specific species and close-ups provide details for identification of a species of interest.
Focus
Attention is naturally drawn to the area of the photograph that is in focus. For landscape scale photographs, most of the scene should be in focus. For subjects closer in, the photographer should be sure the most important part of the photograph is in focus. For plants you can focus on the entire plant or simply the area of interest. Many digital cameras do this automatically for you.
Light
The type, direction and intensity of the light
can affect the color and texture of an image.
Hard light on a sunny day or from a direct
flash emphasizes shadows, highlights, and
textures. Soft light in early morning, late
evening or cloudy days minimizes shadows
and highlights and brings out color and
detail.
The direction of a light source will
also influence the photograph. Front light
(the light source is in front of the subject)
highlights colors while eliminating shadows
and textures. Backlight creates silhouettes
or illuminates translucent subjects. Sidelight
highlights both texture and color of a subject.
Note: Example images are of a native species, Monotropa uniflora,
Indianpipe.
Background
Backgrounds which contrast to the main colors of the subject help make the subject stand out in the photograph, while backgrounds similar to the main colors of the subject make the subject blend in more. A busy background can be distracting and make viewing the subject difficult. Try changing the background by changing the angle of the camera or by placing something behind the subject. It can be as simple as a white or black sheet of paper behind a leaf to help it stand out more clearly.
Digital Cameras
Digital cameras are recommended for collecting data for EDDMapS. Because of the large storage capacity of digital cameras, you can take several pictures of each subject and simply choose the best images to upload with your data. Digital cameras also allow you to easily upload images from your computer directly to EDDMapS.
There are two basic types of digital cameras: point & shoot and
single-lens reflex (SLR). Point & shoot digital cameras are essentially
automatic, with limited ability to adjust settings. The advantages of
point & shoot cameras are their lower cost (compared to SLR cameras),
small size, and light weight. SLR digital cameras are more expensive and
larger, but offer the photographer a suite of automatic settings in
addition to the manual setting and through-lens focusing and framing.
With SLR cameras, interchangeable lenses enhance zoom and macro
features. Zoom lenses allow the photographer to take "close-up"
photographs at a greater distance from the subject. This is advantageous
when the subject is an animal that might become scared or leave if
approached. Lenses with adjustable zooms also allow for easy
manipulation of the framing of a photograph. Wide-angle lenses provide
a wide field of view and can be very useful for landscape photography.
Macro lenses allow for close up photography and can be used to capture
small subjects or minute details necessary for identification. Images
should be taken at the largest size and best quality settings available on
your camera. Send the least edited, least compressed file available.
Note: Most modern cell phones feature a camera with sufficient resolution
for submission to EDDMapS.
JPEG uses a compression scheme that degrades the image each time it
is saved: consequently, it is important to avoid repeatedly editing and
saving the file before submission. If editing, cropping, or enhancing the
JPEG photo using image editing software (such as Adobe Photoshop) is
necessary, perform all operations in one editing session and save the
edited image at the highest quality (least compressed) possible. Retain
a copy of the original file from the digital camera in case the editing
process has to be repeated.
Note: EDDMapS requires images to be uploaded as JPEGs.
The EDDMapS web form allows as many as five images to be uploaded with each record entered. Examples of possible subjects for plants include the following:
- Site view showing extent of infestation, one invasive plant or many
- Flower shape, size, color and arrangement
- Leaf shape and arrangement (opposite, alternate or whorled attachment)
- Fruit shape, size, color and arrangement
- Bark, trunk or stem
- Roots, rhizomes or stolons
As you can see there are more than five possible characteristics to choose from, so pick the five which are most helpful in identifying the plant you are working with. Invasive privets (Ligustrum spp.) have many characteristics in common with native swamp privet (Forestiera spp.); however, the position of the flower or fruit can help easily distinguish between them.
Remember:
- To reduce shake, use a tripod when possible
- Take multiple photographs of the same subject and choose the best for uploading with your data
- Look for the unique features of an invasive species, such as pointed rhizomes on cogongrass or glandular notches at the base of tree-ofheaven leaflets.
- Position yourself so the sun is over your shoulder to get the best light (Front lit image) for sharper details
- Automatic settings on digital cameras work very well for most situations
- Digital cameras usually have a macro setting for close-ups
Remember the images you submit will be used to validate your report to EDDMapS. Good images can make all the difference in your entry being given the highest validation.
