April 25, 2018 at 5:37 pm
By MDIFW Wildlife Biologist Tom Schaeffer
[caption id="attachment_2840" align="alignright" width="436"]
Figure 1. 1993 Aerial Imagery of Cobscook Bay WMA Unit prior to aquisition by MDIFW[/caption]
During the course of aerial eagle nest surveys last week in the Cobscook Bay area; and particularly on one, moderately-steep banked turn to the right; I was presented with a stellar overhead view of a land peninsula which immediately caught my eye. “Wow, that’s a nice-looking piece of land,” was my first thought while quickly realizing that “Oh yeah … that’s one of ours!” Our flight path in turning had taken us directly over one of the 12 land Units which make up the Cobscook Bay Wildlife Management Area (WMA).
What caught my eye was the diversity of cover types and amount of edge effect (where one habitat or cover type transitions into another) which was immediately apparent, but not all that common when flying over thousands of acres of Maine woodlands. Those habitat characteristics are most often associated with reverting agricultural lands or homesteads which were at their peak on Maine landscapes back in the 1950s. Today, many of those reverting lands have either transitioned into mature forests or have been converted to other land uses.
[caption id="attachment_2842" align="alignright" width="472"]
Figure 2. Mowed Fields Locations on Cobscook Bay WMA Unit.[/caption]
When this parcel was acquired in 1995, plant succession was advancing on land that had been previously managed as agricultural pasture/fields, and only a small cleared area remained in proximity of the original homestead (Fig 1).
Starting in 1998, approximately 7 acres of old fields were identified that could readily be reclaimed and annual mowing was initiated to restore this habitat type on the Unit. The following year, 5 acres of those fields were turned over, fertilized, limed, and seeded to provide a nutritious, herbaceous cover crop (Fig. 2).
[caption id="attachment_2843" align="alignright" width="371"]
Figure 3. Early Successional Strip Treatments by Year and Acreage on Cobscook Bay WMA Unit.[/caption]
Beyond what we could recover as field, natural plant succession had resulted in extensive alder and other shrub and woody growth. Alders had advanced in age to the point where they were becoming senescent, setting the scene for more advanced succession. An opportunity to rejuvenate stands of alders, set back succession, and enhance habitat diversification and edge came through a Wildlife Management Institute grant that was awarded in 2007. This management effort established a series of strips that would be mowed with specialized equipment at approximate 5-year intervals, thereby creating different age classes of regenerating alders (Fig 3).
The results of these treatments were obvious from the air last week, even with the dull grays and browns of early spring. In the following September image (Fig. 4), noting the different hues of color that represent various vegetation/cover types, height and age classes, one can readily see the habitat mosaic that has been created. The resulting habitats which lie adjacent to more mature mixed-wood forest types are certain to enhance the abundance and diversity of wildlife on this Unit.
[caption id="attachment_2841" align="alignright" width="693"]
Figure 4. Habitat Mosaic on Cobscook Bay WMA.[/caption]
Figure 1. 1993 Aerial Imagery of Cobscook Bay WMA Unit prior to aquisition by MDIFW[/caption]
During the course of aerial eagle nest surveys last week in the Cobscook Bay area; and particularly on one, moderately-steep banked turn to the right; I was presented with a stellar overhead view of a land peninsula which immediately caught my eye. “Wow, that’s a nice-looking piece of land,” was my first thought while quickly realizing that “Oh yeah … that’s one of ours!” Our flight path in turning had taken us directly over one of the 12 land Units which make up the Cobscook Bay Wildlife Management Area (WMA).
What caught my eye was the diversity of cover types and amount of edge effect (where one habitat or cover type transitions into another) which was immediately apparent, but not all that common when flying over thousands of acres of Maine woodlands. Those habitat characteristics are most often associated with reverting agricultural lands or homesteads which were at their peak on Maine landscapes back in the 1950s. Today, many of those reverting lands have either transitioned into mature forests or have been converted to other land uses.
[caption id="attachment_2842" align="alignright" width="472"] Figure 2. Mowed Fields Locations on Cobscook Bay WMA Unit.[/caption]
When this parcel was acquired in 1995, plant succession was advancing on land that had been previously managed as agricultural pasture/fields, and only a small cleared area remained in proximity of the original homestead (Fig 1).
Starting in 1998, approximately 7 acres of old fields were identified that could readily be reclaimed and annual mowing was initiated to restore this habitat type on the Unit. The following year, 5 acres of those fields were turned over, fertilized, limed, and seeded to provide a nutritious, herbaceous cover crop (Fig. 2).
[caption id="attachment_2843" align="alignright" width="371"] Figure 3. Early Successional Strip Treatments by Year and Acreage on Cobscook Bay WMA Unit.[/caption]
Beyond what we could recover as field, natural plant succession had resulted in extensive alder and other shrub and woody growth. Alders had advanced in age to the point where they were becoming senescent, setting the scene for more advanced succession. An opportunity to rejuvenate stands of alders, set back succession, and enhance habitat diversification and edge came through a Wildlife Management Institute grant that was awarded in 2007. This management effort established a series of strips that would be mowed with specialized equipment at approximate 5-year intervals, thereby creating different age classes of regenerating alders (Fig 3).
The results of these treatments were obvious from the air last week, even with the dull grays and browns of early spring. In the following September image (Fig. 4), noting the different hues of color that represent various vegetation/cover types, height and age classes, one can readily see the habitat mosaic that has been created. The resulting habitats which lie adjacent to more mature mixed-wood forest types are certain to enhance the abundance and diversity of wildlife on this Unit.
[caption id="attachment_2841" align="alignright" width="693"] Figure 4. Habitat Mosaic on Cobscook Bay WMA.[/caption]
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