What to Know

*Important Legal Disclaimer*  The information provided in the CNPS Conservation Toolkit is not intended as legal advice. Always consult an attorney for legal questions. The following content is for informational purposes only. Please reach out to CNPS Conservation Program staff for questions about the following information.  

Understanding the broader legal principles outlined in this section will help you understand CEQA’s disclosure requirements. For CNPS, CEQA guidelines 15124 and 15125 regarding baseline conditions and surveys, and guideline 15380 regarding endangered, rare or threatened species are important in determining if the environmental analysis regarding rare plant species was sufficient to accurately disclose the potential impacts of the project (info on these guidelines can be found in the “Legal concepts in CEQA” dropdown). Projects analyzed under CEQA must also follow other state regulations, you can review other laws protecting native plants on the CDFW California Laws Protecting Native Plants page.

Please visit the Association of Environmental Professionals webpage and visit their CEQA Bookstore “Editions” page to download a free copy of the most recent CEQA Statute & Guidelines Handbook. 

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Explore legal principles, concepts, analysis, and more

Legal principles at-a-glance

Common issues with Environmental Impact Reviews

The following concerns may necessitate additional analysis or legal review:

  • Inadequate analysis of environmental impacts—In this case, the EIR fails as an “informational document.” 
  • Failure to analyze specific impacts to resources—For example, does the analysis focus on rare species but gloss over sensitive natural communities? 
  • Conclusory statements that fail to show the agency’s analytical route from evidence to action—Analysis needs to be available before the project is approved, so the public can be informed and has an opportunity to comment. 
  • Trying to fix deficiencies after the fact—By trying to make up for omissions in the EIR’s analysis through post-EIR errata or other, red flags may arise.
  • Inappropriate mitigation—This would include measures that are not likely to protect an species that would be impacted because they are speculative or vague, rely on transplantation without demonstrating that transplantation or establishment would be successful, or does not include maintenance or monitoring requirements.
  • Deferred mitigation—Agencies will often delay designing mitigation measures until a later time, sometimes after the project is approved or construction is about to begin. 
  • Inadequate botanical surveys or no surveys at all
  • Lack of long-term monitoring—The lead agency must adopt a mitigation monitoring and reporting program (MMRP) to ensure that the project’s mitigation measures are implemented. (CEQA Guidelines, § 15097). However, many agencies do not prepare the MMRP until after the project is approved.  
  • CEQA piecemealing—This involves impermissibly breaking up a project into smaller pieces in a way that obscures the full environmental impact of the project. 
  • Conclusions not supported by evidence 
  • Failure to consider a reasonable range of alternatives 
  • Tiering from program EIRs without preparing additional documentation—When a new project is not entirely considered in the scope of the program EIR, a new Initial Study, and its subsequent reports, must be prepared. 

 Always check the most recent CEQA guidelines.

Legal concepts in CEQA

These foundational legal concepts are central to the CEQA process:

  • EIRs are meant to be informational documents, providing decision makers with a full picture of the project. CEQA Guidelines Section 15121(a) states that “An EIR is an informational document which will inform public agency decision-makers and the public generally of the significant environmental effect of a project, identify possible ways to minimize the significant effects, and describe reasonable alternatives to the project.”  
  • Failure to determine the presence of special status species on the project site violates CEQA’s baseline requirements and undermines informed decision-making.
  • An EIR must include sufficient detail to enable those who did not participate in its preparation to understand and meaningfully consider the issues raised by the proposed project. 
  • If surveys conducted during the environmental review period are found to be flawed, replacement surveys must be conducted prior to project approval. 
  • Project description and environmental baseline must be accurately described (Guidelines 15124, 15125). An EIR needs to provide certainty with respect to the project description and the environmental setting (i.e., the environmental baseline from which the agency will assess whether the project’s impacts will be significant).  
  • Botanical surveys: CNPS interprets this to require that the EIR include appropriate, protocol-level survey data that provides accurate information about the plants, vegetation communities, and habitats that exist on the project site, so that the EIR can accurately analyze how the project will impact those species and habitats. Failure to conduct protocol-level, seasonally appropriate botanical surveys following periods of adequate rainfall prevents the EIR from accurately assessing the project’s impacts to plants. 
  • Endangered, rare or threatened species: Section 15380 of CEQA defines which taxa should be analyzed for impacts. For CNPS, this is important because it requires that impacts to species not listed under the Federal or State Endangered Species Act be analyzed and mitigated if the species meet certain criteria. All taxa with a California Rare Plant Rank (CRPR) of 1 or 2 meet these criteria and plants in the Rare Plant Index with a CRPR of 3 or 4 may meet these criteria depending on the significance of the impact and the abundance and range of the taxa. For example, it could be argued that a list 3 or 4 species should be considered for impacts if it is locally rare in the jurisdiction where a decision is being made (i.e. project activities could threaten the taxa with extinction within the jurisdiction, even if it is more common elsewhere). 

A species of animal or plant is:  

  • (1) “Endangered” when its survival and reproduction in the wild are in immediate jeopardy from one or more causes, including loss of habitat, change in habitat, overexploitation, predation, competition, disease, or other factors; or 
  • (2) “Rare” when either:  
    • (A) Although not presently threatened with extinction, the species is existing in such small numbers throughout all or a significant portion of its range that it may become endangered if its environment worsens.
    • (B) The species is likely to become endangered within the foreseeable future throughout all or a significant portion of its range and may be considered “threatened” as that term is used in the Federal Endangered Species Act. 

Analysis and evidence

  • Guideline 15151 states that “An EIR should be prepared with a sufficient degree of analysis to provide decision-makers with information which enables them to make a decision which intelligently takes account of environmental consequences.” 
  • EIRs must contain facts and analysis, not just the bare conclusions of a public agency. An agency’s opinion concerning matters within its expertise is of obvious value, but the public and decisionmakers, for whom the EIR is prepared, should be presented with the basis for that opinion so they can make an independent, reasoned judgment.
  • An EIR must “disclose the analytic route the agency traveled from evidence to action.” 
  • Agencies are supposed to consider evidence in making their decisions. Conclusions and findings must be supported by substantial evidence. This does not mean, however, that an agency’s conclusion is wrong or unlawful if better evidence supports a different conclusion. 
  • The effectiveness and enforceability of mitigation measures must be supported by substantial evidence in the record. 
  • The document presents conclusions that, even if true, are insufficient to fulfill the informational purpose of an EIR. 
  • The adequacy of the EIR’s analysis is determined “in terms of what is reasonably feasible” for the lead agency (CEQA § 15204 (a)). This means that they are not required to try every possible test and every possible method of mitigation, just what is reasonably feasible for them. 
  • Failure to acknowledge potential impacts violates CEQA’s requirement that reasonably foreseeable impacts be disclosed and analyzed. 
  • Post-hoc analysis is impermissible. CEQA requires agencies to discuss a project’s potentially significant impacts in the draft EIR and final EIR (CEQA Guidelines, § 15120, subd. (c); see also id., §§ 15125, 15126.2). To the extent an agency omits an adequate discussion of a project’s potential impacts in its EIR, it cannot afterward “make up for the lack of analysis in the EIR” through post-EIR analysis. To find otherwise, after all, would deny the public “an ‘opportunity to test, assess, and evaluate the newly revealed information and make an informed judgment as to the validity of the conclusions to be drawn therefrom.’” 


  • The agency must mitigate significant impacts to be “less than significant,” if feasible. 
  • An EIR’s failure to include enforceable, concrete mitigation with measurable performance standards violates CEQA. [CEQA guideline 15126.4] 
  • Deferred mitigation is not okay unless the agency commits itself to the mitigation, describes specific performance standards the mitigation will achieve, and identifies types of actions that will feasibly achieve those standards and will be considered, analyzed, and incorporated into the mitigation measure. [CEQA guideline 15126.4] 
  • The feasibility and effectiveness of a proposed mitigation measure must be supported by substantial evidence in the record. Conclusory and vague statements do not meet CEQA’s requirement that the efficacy of mitigation be supported by substantial evidence. 
  • Proposed mitigation that is unlikely to occur, unlikely to be successful, or inaccurately describes how impacts would be reduced to less than significant through mitigation and should be excluded from an EIR.

New/missing information

A lead agency may be required to recirculate an EIR when significant new information is added to the EIR after the draft EIR is made available for public review. (CEQA Guidelines § 15088.5) 

Other agency involvement

An agency must acknowledge the conflicting views of expert agencies and must provide a factually supported explanation of why that agency’s recommendations were rejected. 

Impermissible CEQA piecemealing

CEQA requires that the agency review the whole of the action that may result in direct or indirect environmental changes. Dividing a large project into smaller pieces and reviewing each piece separately in individual environmental documents, rather than reviewing the whole project in one document, to reduce the apparent environmental impacts of the project is not allowed.