Natural community edition

Associations are grouped into Alliances, Alliances into Groups, and upward, as follows:. The classification for California was first published as the Manual of California Vegetation in , updated in the second edition of the Manual Sawyer et al.

However, because we are continually updating the classification based on new projects, much information is also in project-specific classification and mapping reports. The classification also includes Semi-natural Alliances and Special Stands.

Semi-natural Alliances are strongly dominated by non-native plants that have become naturalized in the state. Special Stands are specific patches of vegetation in the landscape that are unique from other patches, which may appear structurally distinctive as well as rare. The rare species typically defines the type e. Certain rare plants establish with a unique set of species within certain climatic and edaphic conditions, and they typically co-dominate with a rare assemblage of species.

Provisional Alliances and Provisional Semi-natural Alliances are types for which we have fewer than 10 stands sampled, but which we expect will prove to be more widespread. However, since the ranking methodology has become more transparent and defensible through the advent of a rank calculator. For rarity, the ranking involves the knowledge of range and distribution of a given type of vegetation, and the proportion of occurrences that are of good ecological integrity.

Threats and trends are likewise considered in categories such as residential and commercial development, agriculture, energy production and mining, and invasive and other problematic species and genes among others. Threat scope typically assessed within a year timeframe for vegetation and severity are used to calculate an overall threat score, which is added to the overall rarity score for a single rank of 1 through 5.

Evaluation is done at both the Global full natural range within and outside of California and State within California levels resulting in a single G global and S state rank ranging from 1 very rare and threatened to 5 demonstrably secure.

A question mark? We have not provided the G and S rank for all associations in the current version of the list. However, associations currently designated as being of S3 or rarer are indicated with a Y in the Sensitive column. For alliances with State ranks of S1-S3, all associations within them are also considered Sensitive. Note that Alliances that are not considered sensitive may contain associations that are marked with a Y in the Sensitive column.

Membership rules for associations can be found in project-level reports as referenced in the MCV Online Alliance descriptions. Ranking is an ongoing process and we expect to provide association level ranks for all of the S3 or rarer entities in the future.

Please note that Semi-natural Alliances are not ranked, as these are defined by non-native species. As of , about half of California has been mapped and classified according to the state and national standard. Accordingly, not all Sensitive Natural Communities have been described, and the ranks of some current communities may change as we refine their known distributions. However, rankings are based on the best available information. These MMUs are used for regional-scale projects and are based on the available imagery or other data and the budget or speed at which the mapping must be done.

For project-level review maps, the MMUs will likely be smaller; higher resolution imagery and the ability of ecologists to visit all or most of the stands on the ground can allow a higher resolution map. MMUs may also vary by lifeform, with even very small MMUs for sensitive herbaceous communities, for example, Selaginella bigelovii stands on a rock outcrop.

They may also be smaller for types of concern such as invading Arundo donax stands that will need treatment, depending on the purpose of the map. MMUs will depend on the needs or requirements of the lead and trustee agencies and the needs for impact assessment and mitigation planning. A consideration related to this is the separation distances between trees and shrubs, which can help determine, for a particular landscape, what is a stand of shrub or tree vegetation vs. As noted above, some associations are considered sensitive even though the alliance in which they nest are not.

Thus, an alliance-level regional map may not portray stands of association-level sensitive natural communities. This cannot be used to satisfy permit or regulatory requirements. This new edition contains significant changes from the original version, including many community name changes and newly-described natural community types. These changes are summarized in this document in Appendix 2. This document also includes a key to the natural communities of New Hampshire in Appendix 3.

Currently, this edition is only available electronically. This new edition includes several newly-described natural community systems, as well as a key to the natural community systems of New Hampshire in Appendix 3. Key to the Natural Communities of New Hampshire - A standalone version of the natural community key also found as an appendix in the Natural Communities document.

NH Natural Heritage has created this beautiful and informative page book describing the state's natural communities and environment. You can order it on the publisher's website.