Bird Friendly Green Energy?
A case study of the sage-grouse management in Wyoming is promising. The sage-grouse is a large ground-dwelling bird up to 30" long and 2' tall. The bird is highly dependent on sagebrush for food as well as cover in the winter and a safe spot to nest in the spring. Much of it's habitat is now fragmented or destroyed. The population is in decline and the US Fish and Wildlife Service has listed the species as a candidate for Endangered Species Act protection.
In 2007 Wyoming formed a task force called the Governor's Sage-Grouse Implementation Team. They were to come up with a conservation plan that would help ensure the sage-grouse population as well as provide opportunities for further development, such as wind farms and transmission lines. No easy task!
All told, the Audubon Society, federal agencies, the Governor's Sage-Grouse Implementation Team, along with ranchers, wind, oil, and gas representatives came together with a plan of action. They had poured over decades of data related sage-grouse breeding grounds and needs throughout the entire state and into neighboring states. After in-depth analysis, they discovered that some habitat was far more valuable than others. In effect, they estimated that by protecting 60% of the range they could protect the entire breeding habitat. Ultimately the plan would end up protecting 80% of the breeding population.
There are those that question the plan's ability to stop the decline of the sage-grouse. Notably, there are concerns that the core area set aside may not be large enough. The breeding grounds are protected, but the seasonal habitat is not. The US Fish and Wildlife Service is keeping a close eye on the sage-grouse population and has indicated that it will not hesitate to list it if the measures prove ineffective.
Scientists are building off of this experience. They are using ecological data to help determine locations for green energy with the least environmental impact and the most economical return. For example, wind farms are being pointed toward mined lands, agricultural lands, etc.
Prioritizing the conservation of the highest quality habitat at the cost of the development of lesser habitat can be a bitter pill to swallow. Truly, the battle of preservation vs conservation (or Muir vs Pinchot) will continually be debated as we strive to be responsible stewards of our planet.
Human Population and the Geography of Vulnerability
It is estimated that the number of humans living on earth has surpassed seven billion according to United Nations demographers. Our population is exploding at an exponential rate. Knowing that our future holds an ever-increasing number of humans, what does this mean for our planet? As arborists, how can we minimize our impact to the most vulnerable species?
In 1973 Congress passed the Endangered Species Act (ESA), recognizing our nation's natural heritage of, "esthetic, ecological, education, recreational, and scientific value to our Nation and it's people." This was and is landmark legislation. The ESA works well to protect endangered or threatened species and their habitats, but does little to prevent populations from becoming endangered or threatened. Once a species has become endangered, the population has a very small genetic pool to draw from and the likelihood of the species recovering gets smaller and smaller as their numbers dwindle. It is far easier and healthier for the population to be maintained in larger numbers. The key is identifying areas of concern before they become a concern. New studies on geography and human development patterns will inform conservation efforts moving forward.
The geography of vulnerability: incorporating species geography and human development patterns into conservation planning was published in Biological Conservation. This study was conducted with the understanding that the geographic distribution of species needing protection is the cornerstone of any effective conservation plan. Additionally, habitat destruction is the most frequent cause of the endangerment of species (Wilcove et all, 1998).
The study focused on limited-range species of birds and butterflies that are not currently considered endangered or threatened. The ranges for these species often crossed political boundaries into adjacent countries. However, very few countries have legal protections in place for endangered species. For this reason, it is even more important that the portion of their range that extends into the US be protected. The US breeding ranges for these birds and butterflies were identified and the overlapping areas were mapped.
Counties that contain both restricted-range birds and butterflies.
The study then used projected changes in human population density along with several measures of anticipated habitat loss including, increase in developed land area, increase in urban road mileage, and the total amount of undeveloped nonfederal land available for potential development. In general, areas with larger amounts of undeveloped land were at greater risk for habitat loss. With these parameters, Texas, Florida, and California stood out as states with a relatively large number of restricted-range species and a high likelihood of significant losses of natural areas in the near future. These areas were termed “hot spots of vulnerability” (Abbitt, Scott & Wilcove, 2000).
US counties identified as hot spots of vulnerability based on the projected population density increases and the presence of limited-range species.
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California
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Florida
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Texas
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Habitat Conservation Plans (HCPs) are used throughout the US as a way to address endangered species controversies on nonfederal land. HCPs are developed under the Endangered Species Act and help protect flora and fauna while allowing ecologically sensitive development/projects to continue with mitigations for impacts to species and their habitat. It has been encouraged for new HCPs to expand their protection to the limited-range species and their habitat. Protecting these hot spots of vulnerability will help prevent the occurrence of additional endangered species as our human population continues to expand.
As our human population grows, our impact on our surrounding ecosystem grows. As we squeeze the local flora and fauna into ever-decreasing areas, we need to be aware of the long-term consequences. Paying attention to these hot spots of vulnerability and taking extra care to protect the wildlife found in and around trees while arborists are on the job will help maintain biodiversity now and in the future.
The Avian Rookery
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Arborists and tree services should know how to identify an avian rookery.
A rookery is a place where a group of birds or social mammals (such as penguins or seals) breed, nest, or raise their young. The name ‘rookery’ comes from the rook (Corvus frugilegus), the most abundant bird in the crow family in Europe and Asia. These crows commonly build nests and roost in treetop colonies.
Rookeries are used by several bird species such as herons, egrets, cormorants, and even turkey vultures. Large trees or groups of trees are generally the preferred locations for rookeries. Island trees can be especially sought after by nesting wading birds, as seen in the photo. |
Common egret rookery
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It is very important that arborists and tree service professionals be able to identify potential rookeries. An arborist should always perform a pre-work survey before beginning any pruning, maintenance, or removal project. Keep an eye out for multiple nests or groups of birds in or around the tree. Look for white wash and down feathers around the base of the tree.
If an arborist or tree service professional identifies a rookery, it is very important to avoid disturbing the birds in any way. Rookeries may be used by the same birds for many years. These locations are often protected areas to ensure a safe location for birds to nest and raise their young. | |
