Indicator Species
Table of Contents
Introduction
What are Indicator Species?
"Indicator species are defined as species which can provide information on ecological changes and give early warning signals regarding ecosystem processes in site-specific conditions due to their sensitive reactions to them." - Earth Data: Indicator Species
Different species can indicate different things to us. Some species such as fireflies and amphibians can indicate an untouched biome with minimal pollution including pesticides, light pollution, and low foot traffic (tourists often kills fireflies by unintentionally trampling them).
Other indicator species such as plants can indicate qualities such as acidic vs alkaline soil, high frequency flooding and lingering moisture (avoid building homes or businesses in such areas!), or other useful information.
Alternative Names
"They can also be called sentinel species, indicator organisms, biological indicators ('bioindicators'), biological markers, or environmental indicators. The latter three expressions do not necessarily refer to species but also to other environmental elements which can indicate environmental changes." - Earth Data: Indicator Species
About This Page
We start out with basic information about what indicator species are, then list some common types and what they are often used to indicate. Further down the page we have a growing directory of regional guides and lists of indicator species. After that our Resources section includes general educational information for children and adults including basic class resources for younger kids, up to scientific papers explaining how to choose appropriate indicator species for habitat monitoring, as well as methodologies, field safety, and pitfalls to avoid.
How Indicator Species Help Us
Science & Policies
"Scientists at the Environmental Protection Agency (EPA) and experts in other research groups that study biomonitors use indicator species to gather data and formulate case studies or models of specific environments.
Since keystone species are more sensitive to climate change, studying them provides researchers with the comprehensive data needed to advise society on necessary changes. These recommendations could help populations make changes before it is too late for endangered species like the spotted owl or the African elephant, whose numbers are threatened." - MasterClass: Indicator Species
Examples of Indicator Species
5 Types of Indicator Species
"Indicator species, or biological indicators, are living organisms that rely on ecosystem health to thrive and reproduce. Scientists study these organisms to gather data on environmental changes. Here are five examples of indicator species:
Amphibians: Freshwater frogs and toads have exceptionally permeable skin, which enables these amphibious species to provide an early warning of decreased water quality and changes in environmental conditions.
Crustaceans: Ecologists test fish and shellfish for heavy metals, pesticides, and plastics to gauge the effects of agricultural runoff and other water pollution issues. Crustaceans can also provide researchers with indications of the alkalinity or acidity of large bodies of water.
Lichens: Mosses and lichens in old-growth forests—for example, in the Pacific Northwest region of North America—can be some of the best ecological indicators of water and air pollution in temperate forest ecoregions.
Macroinvertebrates: Very small animals like microorganisms and macroinvertebrates can provide researchers with a detailed picture of ecosystem health in waterways and sediment. These organisms can provide researchers with extensive data if several species cohabitate in a compact biosphere.
Wetland Mammals: Manatees, river otters, and beavers are examples of species that typically live in fragile wetland ecosystems, which have some of the best biodiversity on the planet. The population size, reproduction rates, and general health of bioindicator species in wetland areas can provide scientists with a clear picture of degenerating habitats." - MasterClass: Indicator Species
Animals
Beavers
Butterflies
"Butterflies are increasingly being recognised as valuable environmental indicators, both for their rapid and sensitive responses to subtle habitat or climatic changes and as representatives for the diversity and responses of other wildlife." - UKBMS: Butterfly Indicators
Dragonflies
"Dragonflies are an excellent bio-indicator (“bio” meaning living indicator) of water health. Their entire lifespan is intricately tied to the water which means they need high water quality to survive to adulthood. They are susceptible to high levels of pollution, such as physical garbage, chemicals and fertilizer runoff, and sediment erosion which can cover and suffocate eggs and nymphs.
Throughout their life cycle, dragonflies are also food for many predators like frogs and birds. This means any toxins in their body will bio-accumulate in animals found higher up on the food chain. While a single dragonfly may not have enough toxins present in its body to kill it, a higher up predator like a frog or swallow may accumulate enough toxins from all of its diet of dragonflies and other insects, resulting in mortality. This bodes even worse for top predators like hawks and falcons that eat animals like frogs or swallows." - Watersheds: Dragonflies as a Bio-Indicator of Water Health
Distribution of Organisms: Indicator Species "Abiotic factors are non-living variables. Biotic factors are the interactions between organisms. Both affect diversity and distribution. Sampling helps us to estimate numbers of organisms in an area."
Platypus
In addition to serving as an "ambassador species", the "platypus can serve as an indicator species of waterway health as they are usually the first to return to waterways after water quality rehabilitation and conservation efforts have been established." - Land Care NSW
Plants
Mosses
These often indicate acidic soil.
Marine & Reef Indicator Species
"There are certain fish, invertebrates, algae and coral that are indications of a healthy reef ecosystem. During our monitoring efforts, we chart the absence or presence of these organisms to indicate the health of the reef.
Some species include margates, parrots, butterflies, nassau grouper, snapper, grunts, banded coral shrimp, trumpet tritons, pencil urchins, long spiny urchins, lobsters, flamingo tongues, sea eggs. sand, silt, hard coral, soft coral, sponges, NIA, rock RKC and rubble." - Diving with a Purpose: Indicator Species
Other
Lichen
Distribution of Organisms: Indicator Species "Abiotic factors are non-living variables. Biotic factors are the interactions between organisms. Both affect diversity and distribution. Sampling helps us to estimate numbers of organisms in an area."
Indicator Species by Region
This section is itended to give people a referance of their own local indicator species. These might not be full guides, particularly as we are constantly learning new ways in which different species can indicate important information.
International
Oceans
Diving with a Purpose: Indicator Species Click images to enlarge photos of various indicator species. These unfortunately don't have names or descriptions.
Europe
UK
England
Burgess Park: Indicator Species species listed with their names and photos, as well as what they indicate.
England Biodiversity Indicators 2023 This includes a list of non-native species.
Norfolk Wildlife Trust: Habitat Indicator Species "The species lists ... are laid out by habitats and help you to find out which habitats you are surveying – you will see that some species occur in several different habitats."
Durham County Council: Ancient Woodland Indicator Species "Species indicative of ancient woodland found in County Durham "
Ireland
Farming For Nature: Indicator Species – Free Agri-Monitoring Tools for Your Farm! "Indicator species are animals or plants whose presence provides particularly useful insights into the health and quality of your farmland."
Scotland
Epiphyte Communities and Indicator Species An Ecological Guide for Scotland’s Woodlands (PDF)
NatureScot: Scotland's Indicators "Indicators let us monitor changes in Scotland’s species, habitats and landscapes, and reflect wider changes in the natural environment."
North America
Canada
Inventory of Ecosystem Indicators in Canada's North for the Northern Ecosystem Initiative (PDF) includes animal and non-biological markers.
Lichens as Indicators of Forest Health in Canada (PDF) this paper lists lichens according to what pollutant they can help indicate (metal, acid rain, photo-chemicals, etc.), as well as where they are found: Northern, Eastern, Central, or Western Canada.
Ontario
USA
California
Los Angeles Public Library: Bio Blitz: Indicator Species "the City of Los Angeles is particularly interested in knowing where certain biodiversity indicator species are found."
Biodiversity Indicator Species: A Guide to the City of Los Angeles’ Charismatic Umbrella Species (PDF)
Maine
University of Maine Extension: Indicator Species Includes a listing of plants, birds, amphibians, and insects. Click each name or photo for detailed datasheets that include photos and explanations of the species impact and interactions with other species or environmental factors.
Oceana
Australia
NSW
Salinity Indicator Plants (PDF) "This booklet is based on information provided in Spotting Salinity Using Indicator Plants, which was produced by the NSW Department of Land and Water Conservation, Hunter Region in 1998, with assistance from the Hunter Catchment Management Trust and NSW Agriculture. Information contained in the plant description section and pictures of some species have been taken with permission directly from the 1998 publication."
Queensland
The Flora Wetland Indicator Species List (WISL) "has been compiled to support the determination of whether a site is a wetland. The Wetland Indicator Species (WIS) in WISL have adapted to living in wetlands and are dependent on them.
The presence of a WIS at a site does not, in itself, confirm the site to be a wetland, but is one line of evidence towards determining the wetland status of a site."
Resources
Kid-Friendly
Distribution of Organisms: Indicator Species This includes a brief guide to how different lichen species can indicate air quality, and list with photos of which invertebrates can indicate certain levels of water pollution.
Studies & Papers
International
Biodiversity Indicators Partnership: National Indicator Data "Global indicators and datasets can offer consistent, reliable and cost-effective information that can be used to report on progress towards global targets. Many of the global indicators brought together under the BIP are comprised of national level data or in some cases the indicator underlying datasets can be disaggregated at the national level."
North America
Canada
Alberta
Indicators for Assessing Environmental Performance of Watersheds in Southern Alberta (PDF) This gives general guidance, but doesn't focus much on specific species.
Organizations
International
The Biodiversity Indicators Partnership "is a global initiative to promote the development, delivery, and use of biodiversity indicators.
Its primary role is to delivering indicators to monitor progress toward global and national goals and targets, such as those established under the Convention on Biological Diversity, and the Convention on Migratory Species and Ramsar, among others. The BIP also supports indicators used in IPBES Assessment reports and for reporting progress towards Sustainable Development Goals. Indicators supported by the BIP are also used by national and regional government."
The organization "has trained 22 Biodiversity Indicator Facilitators from around the world, to support developing indicators as part of NBSAP updating and implementation. The Facilitators are available to assist in the design and delivery of workshops and meetings, using guidance materials developed and tested by the BIP. If you are organizing indicator-related work and would like support from one of the Facilitators in your region you will find a full list of Facilitators here."
Maps
Europe
UK
UK Butterfly Monitoring Scheme: Species Results Click each species' name and click the "Abundance" tab to see their map.