Beginning in the late 1980s, biologists started noticing that an alarming number of amphibian species were declining and going extinct around the globe. Since then, scientists have come to realize that amphibians, which include frogs, toads, newts and salamanders, are declining more rapidly than any other class of animal. These declines and extinctions appear to represent a unique amphibian crisis, a crisis the International Union for Conservation of Nature (IUCN) claims is “the worst we have ever faced.”

Contents 1 The Loss of Amphibians 2 Status of Amphibians in Ontario 3 Threats to Ontario’s Amphibians 3.1 Habitat Loss 3.2 Habitat Degradation 3.3 Habitat Fragmentation 3.4 Unsustainable Harvesting 3.5 Introduced Invasive Species 3.6 Emerging Infectious Diseases 3.7 Climate Change and Ozone Depletion 4 Monitoring Ontario’s Amphibians 5 ECO Comment

The Loss of Amphibians

Amphibian declines are troubling for several reasons. Amphibians are an important component of many terrestrial and aquatic ecosystems. Amphibian eggs, larvae, and adults provide an important food source for fish, birds and mammals. Conversely, as predators, amphibians eat enormous numbers of insects, algae and detritus. Amphibian declines can therefore drastically alter the integrity of ecosystems. Moreover, diversity of amphibian species, as well as biodiversity in general, is a major source of ecosystem potential: species extinctions reduce the resilience of an ecosystem to respond to change.

The physiology and life cycle of amphibians also make them excellent indicators of ecosystem health. Because most amphibians have aquatic and terrestrial life stages, population declines can signify changes in both types of environments. Moreover, because amphibians have moist, permeable skins, they are in intimate contact with their environment and susceptible to changes in water and air quality. As cold- blooded animals, amphibians are also sensitive to changes in temperature.

The fact that this ancient and historically resilient group of vertebrates – a class that has survived through mass extinctions that decimated other species – is declining now, not only points to the potential role of humans in their demise, but underscores the critical state of biodiversity loss around the planet.

Status of Amphibians in Ontario

Of the 27 amphibian species and subspecies native to Ontario, eight are classified as at risk under Ontario’s Endangered Species Act, 2007 (ESA). The scarcity of some species in Ontario, however, may be partly because Southern Ontario represents the northern limit of their distribution and they were never common or widespread here. While populations at the edge of a species’ range have been viewed by some as of limited conservation concern, these populations are important because they are often genetically distinct and necessary to preserving the genetic diversity and long-term survival of the species.

Table 1: Amphibian Species in Ontario

Common Name	MNR Status
Allegheny mountain dusky salamander	Endangered (recovery strategy in preparation)
blue-spotted salamander	Specially Protected Amphibian
central newt
Eastern red-backed salamander	Specially Protected Amphibian
four-toed salamander	Specially Protected Amphibian
Jefferson salamander	Threatened (recovery strategy submitted to MNR); Specially Protected Amphibian
mudpuppy
northern dusky salamander	Endangered (recovery strategy in preparation); Specially Protected Amphibian
northern two-lined salamander	Specially Protected Amphibian
red-spotted newt
small-mouthed salamander	Endangered (recovery strategy not yet initiated); Specially Protected Amphibian
spotted salamander	Specially Protected Amphibian
spring salamander	Extirpated (recovery strategy not initiated; MNR committed to preparing one by June 30, 2013)
tiger salamander	Extirpated; Specially Protected Amphibian
American bullfrog	Game Amphibian
American toad
boreal chorus frog
Fowler's toad	Threatened (recovery strategy submitted to MNR); Specially Protected Amphibian
gray treefrog	Specially Protected Amphibian
green frog
mink frog
northern cricket frog	Endangered (recovery strategy submitted to MNR); Specially Protected Amphibian
northern leopard frog
pickerel frog
spring peeper
western chorus frog
wood frog

Note: The ESA prohibits the killing or harming of threatened and endangered species, as well as the destruction of their habitat. Under the Fish and Wildlife Conservation Act, 1997 (FWCA), it is prohibited to hunt or trap specially protected amphibians. Under the FWCA, farmers and licensed persons can hunt or trap game amphibians.

Over the last several decades, declines have been observed in several amphibian species in Ontario, including the spring peeper, Jefferson salamander, pickerel frog, northern cricket frog, bullfrog and northern leopard frog.

Threats to Ontario’s Amphibians

There is no simple explanation for amphibian declines. Rather, it seems that several natural and human- caused factors interact to affect populations in complex and synergistic ways.

Habitat Loss

The primary threat to amphibians in Ontario appears to be historic habitat loss, resulting from deforestation, road construction, urbanization, and the conversion of natural areas to agricultural use. Although many amphibians require wetland habitat for shelter and breeding, approximately 70 per cent of southern Ontario wetlands have been drained for agriculture and urban development.

Several provincial policies, acts, and plans provide general protection to habitats important to amphibians. Unfortunately, the common thread amongst these instruments is that exceptions still allow resource extraction and the development of infrastructure in or very near amphibian habitat. For example, the Provincial Policy Statement (PPS) allows aggregate extraction and infrastructure (including highways and oil and gas pipelines) in wetlands, woodlands and wildlife habitats. Likewise, if no other viable locations are available, the Greenbelt Plan (GBP) allows transportation and other infrastructure to be built in wetlands.

Even when infrastructure is built around greenbelt wetlands, the required vegetated buffer of 30 metres is likely inadequate to protect viable populations of pool-breeding amphibians. Amphibians can travel up to about one kilometre from wetlands, so scientists recommend that buffer zones around important wetlands be roughly this size. While Ministry of Natural Resources (MNR) forest management policies recognize the importance of protecting amphibian habitat and direct that buffers be retained around wetlands and woodland pools, again these buffer widths may be insufficient.

Ontario’s system of provincial parks and conservation reserves offers some protection to amphibian habitat. However, these areas cover less than 10 per cent of the province’s land base. Furthermore, activities outside protected areas can still threaten amphibian populations within them. The declines of several amphibian species in Point Pelee National Park illustrate that outside threats can compromise these systems.

Habitat Degradation

Amphibian habitat in Ontario that has not been completely lost often suffers from environmental degradation. Even years after their application, environmental contamination by certain pesticides and other agricultural chemicals can cause developmental deformities, behavioural changes, and death in amphibians. Amphibians are very susceptible to nitrogen-based fertilizers, particularly in the larval stage, and the accumulation of phosphorus in ponds and creeks can cause algae to proliferate, depleting oxygen from the water.

The degradation of amphibian habitat can also result from contamination by mercury, road salts, and pharmaceuticals and personal care products (PPCPs). Although little is known of the chronic, multi- generational effects of PPCPs on non-target organisms like amphibians, waste pharmaceuticals can act as endocrine disrupters that affect amphibian growth, development and reproduction. The Ministry of Transportation (MTO) and the Ministry of the Environment (MOE) have made some progress in reducing the amount of salt placed on roads. However, the ECO still urges MOE to develop a comprehensive, mandatory, province-wide road salts management strategy to ensure aquatic and terrestrial ecosystems are protected from chlorides.

Habitat Fragmentation

Even when good habitats remain, habitat fragmentation by roads, development and other barriers can cause population declines. If ponds and wetlands are isolated and separated by inhospitable habitat, migrating amphibians may be unable to reach breeding, summering and hibernation sites. The fragmentation of amphibian populations into small, isolated sub-populations makes them susceptible to local extinctions caused by natural and manmade factors. Roads can also have negative population effects when amphibians become road kill.

MTO has established a Wildlife Mitigation Team to implement road kill mitigation projects (e.g., culverts and crossings primarily for deer and other large wildlife) at high priority areas throughout the Northeastern region. While the ECO applauds these initiatives and encourages the ministry to expand this program, the ECO recognizes that it is not in the ministry’s mandate to monitor wildlife. The ECO reiterates our previous suggestion that MNR take responsibility for identifying amphibian “hot spots.” We also repeat our recommendation that “MNR and MTO collaborate to monitor wildlife crossings on existing roads to determine where mitigation is required and to work together early in the road planning process to identify areas where wildlife passages will be necessary.”

Unsustainable Harvesting

Although the precise effect of harvesting amphibian populations (e.g., for bait, dissection, or human consumption) is poorly known, evidence indicates that its impacts can be significant. Moreover, because frog populations can fluctuate widely due to natural stochastic factors (such as weather or disease), harvest levels that are sustainable one year can drive population levels to collapse the next. Harvesting has been suggested as partly responsible for substantial declines observed in Ontario bullfrog populations. Ontario’s Fish and Wildlife Conservation Act, 1997 (FWCA) and ESA provide protection to several amphibian species from hunting and trapping (see Table 1).

Introduced Invasive Species

The introduction of non-native species frequently causes declines of native amphibian populations via predation, competition, the introduction of pathogens, and hybridization. Alien species of fish, bullfrogs and crayfish have been implicated as major contributors to amphibian population declines.

In Ontario, the introduction of non-native carp to breeding ponds is believed to have played a role in the decline of the northern cricket frog on Pelee Island. Likewise, one of the threats to the Jefferson salamander in Ontario is the introduction of fish to its breeding ponds. MNR’s ban on the commercial harvest and sale of crayfish as bait (see Section 4.11 of the Supplement to this Annual Report) and guidelines for stocking fish are intended to help slow the introduction of invasive predators to amphibian habitats.

Emerging Infectious Diseases

Amphibian declines have been linked to infectious diseases, which appear to be rapidly increasing in incidence and virulence. In particular, the lethal fungal disease chytridiomycosis has been associated with at least 93 declining amphibian species worldwide and appears to be driving amphibian species to extinction. Although the disease does not yet seem to be a major problem in Ontario, a chytrid fungus pathogen has been confirmed as the cause of a bullfrog tadpole die-off first noticed in 2003 in Algonquin Park. The ECO encourages MNR to monitor incidences of this fungus in Ontario and the spread of the disease in similar temperate climates.

Another increasingly-reported cause of amphibian mass mortality events is Ranavirus, an infectious disease-causing virus. In Ontario, Ranavirus has been associated with mass mortality events of wood frogs and northern leopard frogs. Recent studies confirm that the conditions in which frogs are held in bait shops and the transfer of frogs across southern Ontario have contributed to the spread of the disease. Accordingly, in March 2008, MNR banned the commercial harvest and sale of all bait frog species. For a detailed review of this decision, see Section 4.11 of the Supplement to this Annual Report.

While the ECO supports MNR’s commercial bait ban, we believe that MNR should follow the lead of western provinces and also prohibit the personal use of northern leopard frogs as bait. Allowing individuals to continue using frogs as bait fails to completely address the spread of Ranavirus. Moreover, stricter restrictions on the transport of amphibians in the province would help reduce the potential spread of chytridiomycosis.

Climate Change and Ozone Depletion

Climate change threatens amphibian populations in a variety of ways. Because amphibians are sensitive to environmental changes and have limited dispersal abilities, they may be unable to react quickly enough to temperature and moisture changes or more extreme weather events like thunderstorms and droughts. A warmer climate may also exacerbate other threats, including the spread of infectious diseases and the distribution of invasive species.

Because amphibians bask in the sun to maintain body temperature, have thin skins, and lay eggs near the water’s surface, they are also at high risk of increased exposure to UV radiation resulting from the deterioration of stratospheric ozone. Exposure to UV radiation can affect hatching success, development and immune systems.

While Ontario policies and regulations have been developed to control the release of greenhouse gases and ozone-depleting substances, climate change and ozone depletion are caused by emissions both within and outside Ontario’s borders. As a result, provincial mitigation efforts – though important – will be unable to fully prevent the impacts of those global environmental problems on Ontario’s amphibians.

Monitoring Ontario’s Amphibians

The purpose of MNR’s Natural Heritage Information Centre (NHIC) is to track the location, condition, and distribution of all species potentially at risk in Ontario, and assign conservation status ranks to all species where basic knowledge exists. Unfortunately, an MNR review in 2001/2002 found that rare amphibians are inadequately inventoried, monitored, and assessed in the province. Moreover, the review found no capability to track common species, especially to identify and mitigate species declines. In other words, provincial monitoring of amphibians is reactive rather than pro-active.

In areas of forestry operations on Crown land, MNR carries out a Provincial Wildlife Population Monitoring Program (PWPMP) with the purpose of providing long-term trend data on representative terrestrial species. MNR admits, however, that there has been little in the way of long-term, broad-scale monitoring of amphibians. Of the 19 amphibian species found in the Area of the Undertaking, only the red-backed salamander is currently included under the PWPMP. The PWPMP is scheduled to complete a critical assessment of the state of amphibian populations in 2010.

Four volunteer-based programs, coordinated by Environment Canada, Bird Studies Canada and Nature Canada, monitor frog populations in Ontario. Although MNR’s NHIC periodically receives and incorporates data from these surveys into its amphibian database and distribution maps, currently MNR does not directly participate in or fund these programs. Because these volunteer-based programs tend to sample in southern Ontario, none are able to assess the status of species with large or predominately northern Ontario ranges.

ECO Comment

The global decline of amphibians is worrisome, not only because of its ecological implications but also because it indicates that the world’s ecosystems are in trouble. In Ontario, there is an opportunity to use amphibian populations as indicators of ecosystem health and protect habitats based on their needs. The conservation of Ontario’s amphibians, however, requires more than just a “conservation as usual” approach to protecting species in isolated refugia. The multitude of threats that amphibians face requires a novel and multi-pronged approach to conservation across the province. The IUCN calls on all governments to respond to the amphibian extinction crisis, stating that there needs to be an unprecedented commitment to developing policies that conserve these proverbial canaries in the global coal mine.

It is important to monitor amphibian populations in order to identify the early stages of population decline while there is still time to develop effective management approaches. Because changes in amphibian numbers can be difficult to detect, amphibian populations could suddenly crash beyond their threshold to recover, leaving little hope of preventing their demise.

The ECO commends the several volunteer-based monitoring programs for their work in Ontario. However, quantifying amphibian declines and identifying the underlying or causal factors in any kind of comprehensive manner will require long-term and wide-scale population monitoring. We believe MNR should play a central role in monitoring Ontario’s amphibian populations rather than rely on Environment Canada and non-governmental organizations to track the status of “common” species. Furthermore, as important indicators of biodiversity that can tell us much about Ontario’s ecological health, monitoring the status of amphibians should be a featured component of Ontario’s Biodiversity Strategy.

The wide variety of threats to amphibians means that several Ontario ministries make decisions that affect amphibian populations. Consequently, all ministries that consider the environment in decision-making should consider their impacts on biodiversity, including amphibian populations. Moreover, because no one ministry has the mandate or capacity to address the broad range of issues that impact amphibian populations, there is a need to develop a coordinated interministerial amphibian conservation plan. MNR should take a lead role in developing and coordinating such a plan.

Recommendation 5: The ECO recommends that MNR develop and lead a coordinated interministerial plan to protect and conserve amphibian populations, reflecting the full range of threats and challenges.

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This is an article from the 2008/09 Annual Report to the Legislature from the Environmental Commissioner of Ontario. Building Resilience: Table of Contents Information on the official document and its release.

Citing This Article:
Environmental Commissioner of Ontario. 2009. "Amphibian Declines: Canaries in Our Global Coal Mine?." Building Resilience, ECO Annual Report, 2008-09. Toronto, ON : Environmental Commissioner of Ontario. 44-50.