Climate change is increasing the risk of extinction of wildlife species and reducing the populations of many hunted wildlife species in Michigan. The state has set ambitious renewable energy targets, and solar energy will be an important component of Michigan’s clean energy future. However, some of the benefits of solar energy development could be offset by harms to wildlife if certain best practices are not followed. Other best management practice (BMP) documents for solar energy and wildlife do exist, but they lack a Michigan perspective and framework for weighing the relative context-specific benefits of various practices. This set of BMPs adds specificity to Michigan’s unique geography and relevant wildlife species.
The intent of this set of best management practices (BMPs) is to encourage voluntary conservation practices that benefit both rare and common wildlife in Michigan. Best practices represent a different threshold than laws and regulations, which apply to all (Sinha et al. 2018); BMPs tend to be practices that may not be appropriate in the same way in all cases. A secondary intent of this set of BMPs is to highlight some ways in which Michigan regulations regarding solar energy development and operations differ from those of other states, especially regarding fencing and state-listed threatened and endangered species. The regulatory environment for solar energy development in Michigan has been and continues to be dynamic. We have attempted to clearly distinguish in this document best practices, which are voluntary, from regulations, which are not voluntary.
Federal and state wildlife agencies are distinct entities. Each has its own jurisdictions and enforces its own laws through different sets of regulations and policies. Solar energy developers and operators are responsible for following both sets of regulations. The state list of endangered species, for instance, has more than 400 species, and unlike the federal ESA, the state law protects plants and animals equally. Within their borders, state wildlife agencies have jurisdiction over all wildlife, which are managed in trust for the state’s citizens. We encourage solar energy developers and operators to become familiar with state wildlife laws and regulations, including the state endangered species law and the wildlife conservation order. Communication with the Michigan Department of Natural Resources (DNR) consistent with recommendations made in the Communication Framework for Solar Energy Project Proponents and State Fish and Wildlife Agencies jointly published by the Association of Fish and Wildlife Agencies and the American Clean Power Association is one way to become familiar with state laws and species and their habitats.
Climate change is a major threat to wildlife and their habitats in Michigan (Hellmann et al. 2010, Hoving et al. 2013), and the burning of fossil fuels for energy generation is increasing the severity of that threat (Pörtner et al. 2021, IPCC 2023). A Wildlife Division report estimated that 54% of 400 wildlife species were vulnerable to climate change, including 61% of rare species and 17% of game species (Hoving et al. 2013). Thus, the transition to renewable energy sources and away from energy sources that perpetuate and worsen climate change is an important wildlife conservation strategy (Pörtner et al. 2021). Other benefits of solar energy include reduced air and water pollution. If solar is developed on sites that were formerly row crop agriculture, other benefits include reduced long-term soil and water runoff, protection from land conversion to urban or commercial uses, and increased grassland habitat for some wildlife species (Fleming 2025). Despite the inherent benefits, renewable energy developments can also come with costs. Solar developments in the wrong place or implemented in the wrong way could cause considerable harm to forestry, recreation, or wildlife habitat values. Creative approaches to siting, design, and operations can capitalize on benefits from solar while reducing costs, both financial and to various land use values (Nordberg et al. 2021). Solar impacts to wildlife are an area of active research (Gómez-Catasúset et al. 2024).
Michigan has set an ambitious goal for transitioning from fossil fuel energy sources to renewable energy: economy-wide clean energy by 2040. Solar energy will be a major part of the new energy mix. Michigan’s two major electric utilities, Consumers Energy and DTE, have set a goal of 23,400 megawatts (MW) of solar energy by 2040.
Solar energy requires extensive use of relatively flat and open land. Because each megawatt of solar requires about 5 to 10 acres of land with current technology, Michigan is estimated to need 117,000 to 234,000 acres of solar. If distributed evenly among Michigan’s 1,240 units of local government, that would be roughly 100 to 200 acres per township. However, because of economies of scale, the distribution of open land, and existing transmission infrastructure, most of the development will be concentrated in a smaller number of large facilities of hundreds or thousands of acres. This can represent a significant land use change at the local scale, even if it is relatively small in the context of 10 million acres of agricultural land in the state. The high-end estimates of solar build-out in Michigan would represent less than 3% of agricultural land in the state, which is much smaller than the area currently devoted to ethanol production, which is between 7% and 10% of agricultural land in Michigan (Sinclair 2024).
The Michigan DNR developed these BMPs after reviewing national and regional guidance as well as other states’ BMPs. We found that there were two gaps: existing documents either lacked detail regarding land management techniques, or they were specific to ecosystems (e.g., deserts) or species (e.g., gopher tortoises) not found in Michigan. Furthermore, Michigan is relatively unique in that fence height and its effects on wildlife movement are explicitly regulated in Wildlife Conservation Order 2.11. For this reason, we felt it necessary to develop Michigan-specific solar and wildlife BMPs.
The impacts of renewable energy fall on different landscapes and communities as compared to fossil fuels. Renewable energy projects affect a different set of stakeholders and different communities of wildlife. Our goal is to provide information and recommendations to help solar developers and operators to maximize benefits to wildlife while still providing valuable economic services in terms of relatively clean and low-cost energy.
Our objectives in developing these BMPs for solar energy and Michigan wildlife are to:
These BMPs are intended to be used by solar energy developers, operators, and their consultants to incorporate wildlife conservation values into projects. We recognize that these audiences are attempting to optimize across many values, including energy generation, revenue, local community needs and interests, and other environmental considerations. Our goal in developing these BMPs is to provide information that will help developers prioritize voluntary measures to minimize adverse impacts to Michigan wildlife, and to provide a framework by which developers can highlight the beneficial practices they are voluntarily implementing.
Context can be important to understand why certain practices are recommended. For that reason, we begin with a description of Michigan wildlife that might be affected, positively or negatively, by solar energy development.
Pollinators and other insects are important parts of ecosystems, both for the ecosystem services they provide to human agriculture (e.g., pollinating crops) and because they are directly or indirectly responsible for the food base for most wild birds, mammals, and reptiles (Katumo et al. 2022). Diverse vegetation that is rich in native species hosts more abundant populations of arthropods, like pollinators, than non-native or grass monocultures (Flanders et al. 2006). However, establishing and maintaining native wildlife plantings for pollinators, such as monarch butterflies or rare bumblebees, is as much an art as a science (Sexton and Emery 2020). Solar facilities that follow best management practices outlined below can ensure that planted vegetation continues to meet both the needs of pollinators and the needs of the solar facility.
Two types of grasslands are identified by the 2015 Michigan Wildlife Action Plan (SWAP) as priority habitats: Large Grasslands, and Prairies & Savannas. Many species of grassland birds are Species of Greatest Conservation Need in these habitats, representing diverse and healthy grassland systems. Fragmenting grasslands, such as through clearing habitat for solar units, fences, and roads, represents a threat to these birds (Brennan and Kuvlesky 2005). However, little research exists to show direct positive or negative impacts of solar facilities on different species of grassland birds in Michigan. Many grassland birds prefer large blocks of unfragmented habitat (Herkert 1994). They are susceptible to inappropriate pesticide use and mowing during the nesting season in spring and early summer (Stanton et al. 2018).
Michigan is home to 18 species of snakes. Snakes provide many valuable ecosystem services, including eating rodents and insects (Shine et al. 2024, Ghosh 2025). One of the least common snakes in Michigan is the federally threatened eastern massasauga rattlesnake. The rattlesnake is the only venomous snake in Michigan, but as one of the smallest and most docile species of rattlesnake, the eastern massasauga prefers hiding to confrontation.
In the southern half of the state, the eastern massasauga rattlesnake hibernates in crayfish burrows along the edges of wetlands and then hunts and basks in nearby upland fields. In the northern half of the Lower Peninsula, the massasauga can be found in upland fields and forests far from wetlands. Massasauga rattlesnakes and other snake populations can be harmed by people killing them indiscriminately when they encounter them, and attempting to kill a venomous snake increases risk of being bitten (Shine et al. 2024). Reptile BMPs referenced in this document contain information about safely interacting with snakes in a workplace environment. Massasauga rattlesnakes and other snakes are also sensitive to mowing in late July or August, especially if the mower deck is set less than eight inches.
Michigan has four state threatened or endangered turtles, three of which are associated with wetlands. The fourth is the eastern box turtle, which lives in upland forests and often travels between its summer activity areas and winter hibernation areas. Long fenced areas can block seasonal dispersal routes. Because box turtles are very long-lived species and removing even one adult from the population can have serious consequences for the long-term survival of the species (Congdon et al. 1993, Bougie et al. 2021). Fencing, vegetation management, and reptile-specific BMPs can minimize risk to turtles.
Land use change, including road building and clearing or altering of vegetation, can influence aquatic and wetland ecosystem functions. Runoff and erosion patterns and rates can be altered by project development, along with physical elements of stream habitats and wetlands. Increased sediment input, as a result of vegetation removal, is one threat identified in the Michigan Wildlife Action Plan chapter on warmwater streams and their headwaters. Species of greatest conservation need (SGCN), like the rayed bean (a small mussel), redside dace (a minnow), and redbelly dace (a minnow) all require clear, clean water to survive. Siting solar panels within or adjacent to existing linear infrastructure (transmission corridors, roads, etc.), prioritizing use of already disturbed areas, and diligently minimizing erosion are critical to avoiding and minimizing harm to aquatic animals like mussels, insects, fish, and amphibians.
In addition to aquatic species, many rare plants and wildlife call wetlands home. These areas between fully aquatic and fully terrestrial ecosystems are particularly rich in wildlife. Wetlands are also particularly sensitive to habitat loss, fragmentation, and degradation through erosion or poorly planned runoff. Some examples of Michigan’s wetland flora and fauna are the eastern massasauga rattlesnake, wild rice, and Blanchard’s cricket frog. Rare species such as the Blanding’s turtle will use multiple wetland types over their lifetime. Conservation of these habitat types is critically important to retaining these species. Development has the potential to encroach on, alter, or diminish nearly every type of valuable aquatic habitat in Michigan, but converting row crop agricultural land also has the potential to buffer nearby wetlands by stabilizing soil and reducing erosion (Lovell and Sullivan 2006). With appropriate consideration, many of the potential harms can be avoided and benefits can be leveraged.
Bats are one of the most valuable and least appreciated groups of wild animals (Lacher et al. 2019, Frick et al. 2020). By eating insects that cause harm to forests and crops, they prevent billions of dollars in economic damage to Michigan’s agricultural economy (Boyles et al. 2011). Several species of bats in the United States have experienced notable population declines due to a disease called white-nose syndrome, a fungal pathogen introduced from outside North America. Other threats to bats include human disturbance during hibernation, forest habitat loss, climate change, and wind energy development that does not implement appropriate BMPs (e.g., following the Best Management Practices for Wind Energy and Wildlife in Michigan).
The impacts of solar energy facilities on bats are not well studied. The main threat to Michigan bats from solar energy is believed to be clearing trees and/or fragmenting forest habitat, especially in the spring and summer when bats, including non-volant pups, may be roosting in trees. Solar energy facilities may provide significant positive effects on local bat populations by creating grassland vegetation under and around the panels. Grasslands provide habitat for many native insects, and biologically diverse grasslands with wildflowers are particularly attractive to the types of insects upon which bats prey.
White-tailed deer are a common species in Michigan. Many citizens take a special interest in the welfare and movements of deer in their vicinity. Deer will jump over fences that are greater than five feet in height but sometimes will not jump back out. They will instead try to exit through the fence or try to escape underneath the fence, which can cause harm both to them and the fence. For this reason, the DNR regulates enclosures of fences taller than 52 inches. Although there are exceptions to the fencing regulations for human safety, entrapment of deer is illegal. We recommend solar facilities follow the BMPs outlined below, both in fencing design and in operations, to minimize risk to deer and to maintain the goodwill of their neighbors in the local community.
Wildlife often move across the landscape to fulfill their life history needs. These movements might be infrequent (e.g., seasonal migration) or frequent (e.g., bats commuting along hedgerows from roost trees to feeding areas each night). On longer time scales, wildlife are shifting their geographic ranges northward as the climate warms. Corridors of natural cover are important, especially in a changing climate.
Michigan has roughly 17,000 species of plants and animals, and each species has its own relationship to corridors. For this reason, we define wildlife corridors as relatively linear areas of natural land cover, which provide travel habitat for most wildlife species. Several attempts have been made to map wildlife corridors in Michigan, and we recommend using multiple maps to identify potential wildlife corridors.
The Midwest Landscape Initiative has developed a Midwest Conservation Blueprint that includes areas important for connectivity. The blueprint has many layers (under “indicators”) that could be useful for siting; however, the key layers for connectivity are most clear on the Midwest Conservation Blueprint layer itself, which maps areas that are “Important for Connectivity” and “Conservation Priority.”
Additionally, The Nature Conservancy has created a Resilient and Connected Lands (RCL) website that maps corridors. The website has a Resilient Land Mapping Tool. On this tool are several layers. The Resilient & Connected Network (Detailed) layer is likely to be the most informative. Any lands of any color have some connectivity value, but the areas with “concentrated flow” or “recognized biodiversity value” are most sensitive to corridor fragmentation at the scale of utility-scale solar facilities.
Local land conservancies often have similar maps at a finer scale. While these maps capture connectivity for wildlife in general, they are likely to not capture locations or connectivity for specific species or taxa groups such as eastern massasauga rattlesnakes which use wetlands or bats that use forested hedgerows to travel between roosting and hunting areas. When siting facilities, we recommend avoiding project configurations that might sever or block local or regional corridors.
Within the footprint of a given project, providing wildlife movement passages can reduce future risk of entrapping wildlife. Linear wetlands, hedgerows, drainages, streams, or other linear natural cover are features often used by wildlife to move across the landscape. There are often multiple reasons to protect these features, including erosion regulations, stormwater management, or topographic challenges. Extending these features when planning layouts to allow movement through the facility (and avoiding dead-ends) can help wildlife move through facilities.
Solar arrays often are sited on agricultural lands with relatively little habitat value for wildlife, but connections to the grid often cross wetlands, forests, and other more valuable habitats. Where practical, we recommend siting connections to the grid using existing rights of way or along existing linear developments such as roads, pipelines, or other infrastructure to minimize new impacts to natural cover.
Siting utility-scale solar is a complex endeavor which involves many constraints and trade-offs in multiple values. The impact to wildlife from land use conversion to solar energy depends largely on the land use type that is being converted and the geographic context. The spectrum of value to wildlife conservation in Michigan, from least wildlife value to most wildlife value, is:
paved surfaces/urban/brownfield < row crop agriculture < hay/forage/pasture < forest/grassland/marsh < savanna/fen/bog < high quality natural communities.
Thus, all other things being equal, a project sited over an impermeable surface will have the least negative impact to wildlife, and a project sited in a high-quality natural community will have the greatest impact. However, because of constraints of size, contiguity, liability, and proximity to suitable transmission infrastructure, even if we developed all the suitable and available paved, urban, or brownfield sites for utility-scale solar, the total would fall far short of the amount of renewable energy needed to meet Michigan’s clean energy goals. Thus, some utility-scale solar will need to be developed on Michigan’s natural and working lands, including agricultural lands and on existing forested lands.
To determine wildlife value of existing land use in an area, we recommend consulting a wide variety of publicly available datasets. The USGS National Land Cover Database and the Michigan DNR Maps and Open Data Portal are good places to start. The Nature Conservancy has developed a Site Renewables Right online mapping tool which allows the user to toggle on and off different conservation datasets. The Midwest Landscape Initiative’s Conservation Blueprint is another useful tool, which also allows the user to toggle on and off datasets that are relevant to their project and their geography. These tools are broad-scale tools and should be used in conjunction with local and more detailed maps to develop a comprehensive understanding of the risks to local wildlife.
Public land is important to meet clean energy goals. Michigan has the largest state forest system in the country at approximately 4 million acres, and leasing lands for oil and gas extraction occurs throughout the state forest system. In principle, renewable energy development, including utility-scale solar, is consistent with other leased activities. However, there are important considerations when deciding how much and where utility-scale solar is appropriate. These include limitations on some lands that have been imposed by the state legislature, legally binding agreements, and competing values.
Some state public lands have limits as to what uses are allowed on those lands because of legislative limits. In northern Michigan, some lands entered public ownership through tax reversion, purchase using federal wildlife funds, and other funding sources. State law and federal regulations limit developing wildlife-purchased lands to game species habitat and in ways that do not limit physical access of people who wish to engage in hunting and fishing. The construction of the fencing required under the NEC and NESC to exclude human access for safety reasons causes this to be an incompatible use. One cannot fence an area and keep it open to human access.
A best practice on public lands is to identify all legislative designations that may affect whether a given part of the state forest can be developed for solar, including natural areas designations and forest certification. We recommend working with state agency staff early in the process to determine if and where legislative designations may affect siting decisions.
The DNR often enters into legally binding agreements to limit activities on certain lands. For example, the state entered into a Candidate Conservation Agreement with Assurances with the U.S. Fish and Wildlife Service to allow certain activities on some lands and not others to conserve the federally threatened eastern massasauga rattlesnake (EMR). Construction and mowing are not allowed on designated EMR lands. Another legally binding agreement is the Bat Conservation Habitat Conservation Plan (HCP), which constrains tree cutting within solar facilities in ways that would make both construction and vegetation management difficult.
Similar to legislative designations, a best practice is to identify all relevant legally binding agreements that could limit where solar can be sited within an area of interest. Similarly, we recommend working with state agency staff early in the process to determine if and where legally binding agreements may affect siting decisions.
The state of Michigan has repeatedly reviewed their portfolio of public lands to ensure that every acre has conservation value. As part of that review, we dispose of (i.e., sell) public lands that do not meet our high standards of conservation value. For this reason, there are very few public lands where renewable energy would be the highest priority use because the lands are already used for recreation, natural resource management, or conservation. Compared to federal lands, which are reviewed less often, there is often conflict with existing uses when changes in land use are proposed on state public land. Wildlife habitat and access for hunting and fishing are important values, both to the agency and to the people who use those lands.
A best practice to minimize conflict with competing values on public lands is to site utility-scale projects in areas with relatively less conflict with existing uses and to mitigate lost access through other projects that increase access or restore wildlife habitat elsewhere.
Floating solar (solar panels floating on bodies of water) is discouraged in Michigan. Most water bodies in Michigan provide key habitat components for wildlife. Even pools associated with water treatment plants are used extensively by certain waterbirds and are often visited by birdwatchers.
Developers can use the U.S. Fish and Wildlife Service’s Information for Planning and Consultation (IPaC) website to request an official species list for their solar project. Developers can also use the All Species Michigan Determination Key (Michigan Dkey) to assess potential impacts of the project on federally listed species and in most cases, autogenerate an official letter documenting their proposed project activities, conservation measures, and effects determinations for listed species and habitats. When a federal agency authorizes, funds, permits, or carries out a proposed development, the Michigan Dkey can assist users in completing the ESA Section 7 consultation process. The Michigan Dkey can also assist solar developers applying for a state wetland permit issued by the Michigan Department of Environment, Great Lakes, and Energy (EGLE) by evaluating effects to listed species and generating relevant recommended permit conditions. For assistance in using IPaC, applicants should reference the Michigan Field Office’s IPaC Instructions.
In Michigan, a desktop review for a solar development project for known locations of state threatened and endangered species can be procured from Michigan Nature Features Inventory or any other consultant with access to the state natural heritage database. Because wildlife populations and their habitats are dynamic, desktop reviews are valid for one year. Providing proof that the state natural history database has been checked is a key step that allows Michigan DNR staff to begin consultation with a solar energy developer.
Habitat assessments and presence/absence surveys may have seasonal limitations and often must be conducted by experienced professionals that hold appropriate state and/or federal permits. Where surveys are used, effective planning requires early coordination with permittees and adequate scheduling. In some cases, assuming presence of rare species and implementing appropriate conservation measures to avoid or minimize potential impacts may eliminate need for surveys and be a more practicable option.
State threatened and endangered species regulators are available to consult on desktop reviews and to recommend conservation measures that would preclude the need for a state threatened and endangered species permit. In the rare case that take of state listed species cannot be avoided, state regulators are available to negotiate terms of a state permit.
State and federal endangered species regulators in Michigan work cooperatively, and it is usually beneficial to all parties to combine consultation meetings among developers, their consultants, the state endangered species program, and the USFWS Michigan Ecological Services Field Office.
Early consultation can allow flexibility in surveys and siting. If rare species surveys are needed, early consultation allows surveys for species with narrow seasonal survey windows while minimizing impacts to project timelines. Similarly, the presence of threatened or endangered species requires more thorough review of wetland permits, and wetland permits also have specific seasonal windows for surveys. Early consultation can also highlight potential siting problems while there is still flexibility in facility configuration.
The Association of Fish and Wildlife Agencies (AFWA) and the American Clean Power Association (ACP) have developed a set of voluntary communication guidelines to clarify expectations about when and how state agencies desire to be included in discussions about utility-scale solar energy developments. Each state has different laws and regulations, but the guidelines outline some common themes and recommendations around relationship building, preliminary site evaluation, site characterization, construction, operations, and facility decommissioning.
Whereas most BMPs in this document are voluntary, the prohibitions against take of wildlife are not. There are two ways these regulations are relevant to solar energy developments. The first are the prohibitions against the take of deer, elk, bear, or moose as a result of fence construction in an area frequented by wild animals. Certain fence construction constitutes the taking or maintaining in captivity of wild, free-ranging deer, elk, bear, or moose (Wildlife Conservation Order 2.11). The second are prohibitions against the take of any species of plants or animals on the state list of threatened or endangered species (MCL 324.36501 et al.).
It is the responsibility of the developer to abide by both state and federal laws in the construction phases of a project. It is the responsibility of the operator to abide by both state and federal laws in the operations phases of a project.
Plan to incorporate measures that reduce surface water runoff, maintain adequate buffers around wetlands and other water resources, and so on. Consider construction methods that can reduce impacts to streams and wetlands (e.g., rerouting, directional drilling, clear-spanning, or other ways of reducing or eliminating the need for in-stream or in-wetland construction).
The National Electric Code (NEC) and National Electric Safety Code (NESC) require fencing at least 7 feet high for public safety. In addition, in Michigan, any fence over 52 inches in height is considered unlawful take of free-ranging deer, elk, bear, or moose. There is an exemption to the fence height requirements, but only for a facility that does not “kill, harm, capture, trap, or collect animals and which is constructed to… protect public safety…” (Wildlife Conservation Order 2.11). Both conditions must be met for a facility to claim the public safety exemption in Michigan: 1) fencing must be for public safety and 2) it must not kill, harm, or trap deer, elk, moose, or bear. It is the responsibility of the solar facility developer and operator to ensure that the facility does not harm or entrap deer, elk, moose, and bear. Below we list best practices to minimize the risk of entrapping white-tailed deer and other wildlife.
Tall fencing should be installed early in the construction period to avoid encircling and entrapping a population of deer that might be hiding among panels or among natural vegetation within the facility boundary. If fencing will enclose any area of natural vegetation (e.g., a small woodlot), all deer, elk, bear, and moose must be flushed from that area before construction of the fence.
Where consistent with the NEC and NESC, we recommend a 4- to 5-inch mesh fencing material be used to allow most wild animals to easily move into and out of a facility. If chain link fencing is used, we recommend specially designed wildlife escape structures to give small mammals, turtles, and other small to medium sized wildlife a way to get into and out of a facility. PVC tubing can be used along the top and bottom of chain link fences to keep wild animals from getting snagged and injured as they try to jump over or squeeze under fencing.
When a smaller mesh size fence material is used (e.g., chain-link), we recommend elevating the bottom of fences by 4 to 5 inches. When fences are elevated, we recommend attaching the bottom of the fence to a horizontal bar, like the bar at the top of the fence. This will deter deer or other large mammals from trying to climb under the fence, which can cause injury to the animal and damage the fence. It will also allow smaller wildlife, such as foxes or turtles, to freely enter and exit the facility.
As a rule, the Michigan DNR recommends that all fences have an effective height of less than 52 inches; however, because NEC and NESC require fences of at least 7 feet for public safety, we recognize that those fence heights are usually necessary around solar energy facilities. Because a 7- to 8-foot fence has the greatest risk of entrapping white-tailed deer, we strongly recommend adding design features to fences to minimize entrapment and facilitate removing wildlife entrapped in the facility. One design feature to minimize wildlife entrapment is to build berms inside the fence, which can give deer and other large wildlife a way to escape.
Other fence design features to minimize entrapment or facilitate removing entrapped deer is to incorporate one-way escape gates for deer, which can be built into fencing. However, one-way gates must be designed such that they do not allow humans to enter. Gates at corners can also help when trying to encourage deer to leave a facility. Similarly, sections of fence that can be easily dropped and re-erected can make it easier to flush deer from a facility. Other innovative technologies and engineering solutions to deer entrapment should be explored.
Michigan has a strong fence law. Rural landowners are aware of it, and solar facility operators should expect rural landowners to report instances of deer entrapment to the authorities. If deer do become entrapped (and 7- to 8-foot fences without designed features to avoid entrapment make entrapment likely), it is the financial responsibility of the facility operator to remove deer. If removing deer requires culling (and it often does), that must be done under a permit from the Michigan Department of Natural Resources, and that permit includes a per-deer financial cost.
Consider existing deer movement patterns when designing blocks of fenced area and potential passage locations. We recommend breaking up large installations into smaller blocks to allow deer to move through a facility without needing to try to jump over fences, but the size and configuration of blocks and passages is highly dependent on landscape context. Deer are strongly habitual animals, and they will try to follow established deer paths by leaping or crawling under tall fences. Strategically placed passages can avoid long-term maintenance costs associated with deer entrapment and potential culling of entrapped deer.
Deer often move along streams and the edges of wetlands. Thus, passages for deer often coincide with stream or riparian buffers and areas where stormwater considerations make panel placement risky.
As mentioned in the Operations section, we recommend developing and implementing a wildlife fencing and entrapment plan to guide maintenance staff in the steps to take when entrapped wildlife are found. Other recommendations include checking regularly for entrapped wildlife and keeping gates closed except when vehicles are passing through them. Leaving a gate open even for a few minutes can allow wildlife to enter the facility.
The federally threatened eastern massasauga rattlesnake is relatively widespread in Michigan’s Lower Peninsula, and it is extremely difficult to detect using surveys. Michigan also has seven reptiles that are listed as state threatened or endangered. Because Michigan has relatively robust reptile and amphibian populations compared to surrounding states, we recommend that solar facilities developers and their contractors follow the Michigan Amphibian & Reptile Best Management Practices, Second Edition (Mifsud 2023).
Of particular concern are plastic soil erosion control materials and mulching or seeding netting with a plastic net base. These are especially lethal to reptiles and amphibians, which can become entangled and perish. We strongly recommend using soil erosion control and mulching materials that are entirely natural fibers.
Trees are used by bats and birds for nesting and roosting throughout the spring, summer, and fall. Hedgerows and other linear forest features are also important daily commuting corridors between roosting and feeding areas for bats and birds. We recommend that tree clearing be minimized as much as possible, especially living trees that contain holes or cavities and hedgerows that link forest blocks. When tree clearing is necessary, tree clearing in the winter minimizes the risk to wildlife, especially nesting and roosting bats and birds.
Wetlands are valuable to a wide diversity of wildlife. Wetlands are more than just ponds or cattail marshes; they include areas where the soil is saturated for much of the year, such as bogs, vernal pools, and sedge meadows. Established wetlands are effective at drawing carbon from the atmosphere, but soil disturbance or draining can cause them to emit greenhouse gases for years to decades. Wherever possible, minimize the impact to wetlands, especially actions that would necessitate wetland mitigation.
The best ways to establish wildlife-friendly vegetation at solar facilities in Michigan is an area of active development, and best practices are expected to evolve as developers, contractors, and researchers learn what practices are both wildlife-friendly, economical, and feasible. At the time of writing, we are aware of two different wildlife-friendly approaches to establishing predominately native vegetation during the construction phase.
The first approach is planting a mix of native grasses and wildflowers that have a short stature and that bloom at different times during the growing season. In this approach, the wildlife benefit and the cost both rise with more wildflowers relative to grasses both in weight and seeds and with the number of species of wildflowers. In other words, you get what you pay for in terms of wildflower seed. This approach has more natural beauty, which can be important to neighbors, and it benefits pollinators most. It also provides valuable seed and insect food for insect, bird, and mammal wildlife. On the negative side, this approach takes considerable skill by contractors who specialize in native wildflower planting. It often requires a year of site preparation, and there may be several years of frequent mowing and herbicide use to control weeds and invasive plants.
Plant diversity will help support the nutritional needs of Michigan’s pollinators. We recommend a mix of short-stature flowering native plants with species selected strategically so that something is always blooming, and pollen is available during the active periods of Michigan’s native pollinators, roughly early spring through fall (mid-March to mid-October).
Species in seed mixes vary by region and soil type, but a good native seed mix for pollinators will include species like butterfly milkweed, partridge pea, old field goldenrod, purple prairie clover, or lance-leaf coreopsis. A seed mix that includes a large proportion of non-native species such as bird’s foot trefoil will have lower wildlife benefits. Seed mixes with larger numbers of species, more pounds per acre, and seed mixes tailored to specific soil types are recommended, but one needs to balance these benefits with cost. To compare costs, one can search the internet for native plant seed for Michigan or the Midwest. We recommend purchasing native seed or plant material from companies with a track record of providing high-quality native seeds. Some suppliers have been known to mix non-native wildflower seed or garden cultivars which are unlikely to provide the intended benefits to wildlife.
The second approach is planting a mix of native and non-native grasses with short stature and without wildflowers. This approach requires careful balancing of the native and non-native grass mix such that it establishes quickly (to prevent erosion) without converting to a monoculture of non-native grasses. This approach has less natural beauty and less benefit to pollinators (because grasses are wind pollinated). On the positive side, invasive species control (especially Canada thistle) is easier and planting can occur in the same season as construction. The main wildlife benefits are that mowing is less frequent and invasive species are more easily controlled.
A good grass and sedge mix should include species such as little bluestem, Canada wild rye, or slender wheatgrass. If non-native perennial rye is included in the mix, it should be a minor (<5%) component of the mix. Perennial rye will establish a one-species grass monoculture if it is a major component of the mix, and monocultures reduce biodiversity and wildlife value, are more prone to invasive species, and often convert to taller “old field” vegetation which requires more frequent mowing, herbicide, and maintenance. Similar to wildflower mixes, a good grass mix will include 10 to 20 or more species of grasses and sedges.
Where feasible, a water source (e.g., ephemeral pool or low area) will provide resources for pollinators, bats, and other wildlife. Although a water source is not critical, it does generally improve habitat quality. If a field has wet depressions that hold water for a week or more, we recommend not grading or placing panels on those areas. Instead, panel placement and road infrastructure should go around. Persistent puddles in agricultural fields are potentially valuable small wetlands.
Maintaining vegetation with value to wildlife and pollinators within a solar facility is not a trivial undertaking. Without intentional grassland management, native wildflower plantings for pollinators can degrade into grass monocultures or become infested with invasive species or weeds that can impact neighboring farms. We recommend developing and implementing a vegetation management plan that addresses the following:
See the Resources section for more detailed guidance on preparing a vegetation management plan.
State forest land projects should meet a high threshold of habitat quality. Wherever possible, existing non-woody vegetation should be maintained, and grading or other forms of soil disturbance should be minimized. In areas with sandy, low-nutrient soils, establishing new vegetative cover with commercial grass seed mixes may be very difficult or impossible. Panel heights may need to be taller than standard to accommodate existing vegetation on public lands.
Whereas most BMPs in this document are voluntary, the prohibitions against take of wildlife are not. There are two ways these regulations are relevant to solar energy developments. The first are the prohibitions related to “the construction of a fence shall constitute a taking or the maintaining in captivity of wild, free-ranging deer, elk, bear, or moose if the structure is constructed in an area frequented by wild, free-ranging deer, elk, bear, or moose…” as outlined in Wildlife Conservation Order 2.11. The second are prohibitions against the take of any species of plants or animals on the state list of threatened or endangered species. It is the responsibility of the operator to abide by these laws both in the construction and operations phases of a project.
If deer or elk become entrapped in a facility, it is the facility owner’s responsibility to remove them. Although we encourage operators to start with non-lethal attempts to herd deer through a gate or gap in the fence, this can be extremely difficult, especially in large, fenced areas over multiple acres. If deer or elk cannot be encouraged to leave the fenced area on their own, the operator will need to contact the Michigan DNR to secure a permit (and pay a fee) to allow lethal take of each entrapped deer, as outlined in Wildlife Conservation Order 2.11. To qualify for a permit to address deer entrapment, a facility-specific fencing and entrapment plan is necessary. We recommend that the fencing and entrapment plan be developed prior to the start of operations and that it addresses the following:
Michigan’s climate is very conducive to woody vegetation growth. Birds perching on panels will spread tree and shrub seeds into the facility. Mowing periodically is necessary to discourage tall plants, shrubs, and trees from establishing, but mowing also risks harm to wildlife, pollinators, and native plants. Mowing frequency and timing are the best ways to both minimize cost and maximize ecological benefits.
Solar sites should be mowed as infrequently as possible. For wildlife, the best season to mow is the dormant season. The next best season is fall. Mowing in spring and early summer risks harm to ground-nesting grassland birds; mowing in the late summer risks harm to snakes, including the federally threatened eastern massasauga rattlesnake (EMR). The USFWS recommends mowing during the inactive season (not summer) in Tier 1 and 2 EMR habitat or raising the mowing deck to at least 8 inches when mowing during the summer.
One way to minimize risk to wildlife from mowing is to plant a low growing mix of native and non-native grasses and sedges that is free of wildflowers. These grasses and sedges can be established economically because it is relatively easy to control tall invasive plants, such as Canada thistle, when a seed mix is only grasses and sedges. This approach has low value for pollinator wildlife and high value for bird and reptile wildlife. Alternatively, a wildflower-rich planting mix will require more mowing and invasive species control, especially in the establishment phase. This approach has high value for pollinator species but increases risk for birds and reptiles. Both approaches are best practices for wildlife. Sheep or other grazers can be a low-carbon and low-cost alternative to regular mowing. However, the dual uses of solar and pasture need to be addressed early in the planning stages so that water sources, fencing, and vegetation planted are suitable for this dual land use.
Sometimes land management that benefits threatened or endangered species also risks killing a small number of individuals of that species. Mowing fields that contain threatened or endangered pollinators is a good example of this conservation conundrum. Pollinators such as monarch and other rare butterflies and bumblebees need non-forested openings with abundant flowers, but in Michigan’s climate, non-forested openings convert to forest if not mowed, burned, or grazed frequently enough to discourage tree growth.
Programmatic agreements, such as the Nationwide Candidate Conservation Agreement for Monarch Butterfly on Energy and Transportation Lands and the Nationwide Agreement for At-Risk Bumble Bees, exist to provide a legal mechanism to allow activities like mowing on solar energy installation where rare pollinators occur. We encourage solar energy operators to consider becoming a signatory to existing relevant programmatic agreements or working with regulatory agencies to develop an agreement if one does not yet exist for specific activities that affect a federally threatened or endangered species.
Invasive species are native or non-native species that cause harm. Some invasive species can crowd out pollinator wildflowers, degrade wildlife habitat, and grow tall enough to cast shade on panels. It is important in a vegetation plan to distinguish between common and low impact weedy species (e.g., dandelions) and species that could impact energy generation or wildlife habitat if they become established (e.g., black swallowwort, invasive knotweed, Canada thistle, etc.). Consultants and/or maintenance staff should be trained to identify high impact invasive species so that invasions can be managed before they become widespread. Treating invasive species early saves time and money. Treatments usually involve a combination of targeted and carefully timed mowing and targeted and carefully timed herbicide applications.
Extra care should be taken that fast growing, tall vegetation planted in the project periphery as a visual screen does not include invasive species. Non-native ornamental grasses and shrubs, such as miscanthus grass or Bradford pear, while available and inexpensive, also risk invasions into the solar panel part of the project, as well as surrounding natural areas.
A vegetation plan should outline the situations in which herbicides and pesticides can or cannot be used. The plan should minimize their use, reserving it for treating vegetation that threatens facility equipment, operations, or wildlife habitat. Herbicide and pesticide use should be targeted as much as possible (i.e., spot treatments rather than whole-field applications). That said, early detection and prompt use of herbicide is critical to maintaining habitat and minimizing cost.
Pesticide (e.g., insecticide) use should be minimized. Few insecticides are specific to problem insects. Many are equally toxic to bees, butterflies, and other pollinators. Insects also form the base of the food chain for birds and mammals, and changes in insect abundance are especially disruptive to species that feed exclusively on insects, such as bats and certain insectivorous birds. Pesticide use can also affect threatened and endangered insects and best management practices for insecticide use should be implemented in areas near these sensitive species.
Minimize or avoid use of genetically modified organisms (GMOs). GMOs are usually created to allow widespread broadcast of herbicide or pesticide to kill weeds in agricultural settings. From a wildlife perspective, the problem is not the GMO itself, but the management system that is enabled by the GMOs.
As mentioned in the Operations section, we recommend developing and implementing a wildlife fencing and entrapment plan to guide maintenance staff in the steps to take when entrapped wildlife are found. The most important practice to avoid entrapping wildlife is keeping gates closed except when vehicles are passing through them. Leaving the gate open even for a few minutes can allow wildlife to enter the facility.
Sites should be monitored regularly for entrapped wildlife, and for damaged fencing that could allow wildlife to become entrapped. This can be done from roadsides with binoculars. A drone can allow better perspective into the interior of larger facilities.
Vegetation should be monitored annually both to ensure that wildflowers and pollinator habitat continue to thrive and to identify tall or problematic invasives early, when treatment options are less costly and damaging to wildlife habitat.
Research to establish trends in wildlife use and habitat quality can be difficult to draw from one facility. We encourage facilities to work with university researchers to develop cooperative projects (or simply to provide access to researchers) to document the benefits (and costs) of solar energy developments for wildlife.
This set of BMPs was developed by DNR Wildlife Division staff, with input from the USFWS, over the course of two years (2023–2024). We also sought review of previous drafts from DNR staff in 2023. During the time we were drafting this document, the regulatory environment underwent considerable changes. The state threatened and endangered species list was revised, and new laws were passed regarding siting of renewable energy and storage, which required further revisions. A draft of these BMPs was reviewed by external stakeholders in 2025.
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