Fowler’s Toad information: Notes from Dr. Todd Tupper, March 6, 2013.
Please see http://www.savethefrogs.com/lake-erie-toads for more information.
Todd Tupper, PhD
Fowler’s Toad Biologist, Associate Professor of Biology
Northern Virginia Community College, Alexandria Campus, Alexandra, Virginia USA
ttupper@nvcc.edu
Structure of habitat: Fowler’s toads need a mosaic of sand and vegetation, that is they like edge
habitat (ecotones), and usually have burrows near /on the ecotones that they use on a daily basis.
They may burrow on the ecotone during the day, and emerge at night to feed. It is unlikely that
the complex ecotonal structure that is a result of long-term natural ecological processes can be
recreated without extensive research.
The developers plan to bury rocks under the sand (presumably for drainage) at the
construction site. This is incompatible for toad persistence for a couple of important reasons: 1.
Fowler’s toads need to survive harsh winters. They do this by burrowing (in some cases over 2 m
deep) in the sand. The goal is for the toads to make it below the frost line so they do not freeze. If
there are big rocks in the way, the toads will certainly freeze. It’s Canada for God’s sake.2)
Additionally, wetlands like interdunal swales (and even puddles) often serve as important
breeding habitats for the toads. Burying rock will increase drainage, thus disrupting the natural
groundwater hydrology such that any potential breeding habitats that exist directly on the site of
construction would drain too quickly and be lost. In many cases, these swales and fishless
puddles serve as important sources of recruitment for the Fowler’s toads, sending toadlet
biomass into the ecosystem, thus benefitting Fowler’s toad populations and native species that
depend on toadlets and subadults for sustenance.
Migration: Fowler’s toads migrate, and migrate fairly large distances. They do not exhibit much
behavioral plasticity. They will attempt to migrate up to somewhere around 1 km from natal
breeding grounds and then return to the same area eventually to breed. If there is pavement, car
traffic, and a big building in the way, they will not make it to reproduce because they don’t have
the neurological equipment to change migratory paths. They respond simply to environmental
cues and endocrine messages to move.
Artificial substrate: Pavement and artificial lighting are bad for Fowler’s toads. Fowler’s toads
are sit-and-wait predators. They do this while simultaneously thermoregulating. The pavement
will replace natural substrates. At night (during the active season) they will hunker down and
press their bodies against the pavement to absorb heat (as if it were sand). They will
simultaneously be on the lookout for insect prey, which are attracted to light emitted from street
lamps or the proposed development itself (which will attract the toad’s attention). This is
dangerous because the pavement harbors vehicles which invariably run the toads over. It only
takes one vehicle to wipe out most of the toads while warming and feeding. The first defensive
response of the toads is to hunker in a depression in sand. When they hunker in response to a car,
it means death for the Fowler’s toad.
Increase in generalist predator populations: Trash, food and other human waste from the
development will attract mammalian predators which prey upon toads during the breeding season
(when the males are calling) and depredate toadlets after emergence. Raccoons for instance will
enter breeding aggregations and eat the entire toad and leave the heads behind (b/c paratoid
glands). The toads likely tune out (with an auditory locking mechanism) the approaching
predators because they are focused on sounds associated with breeding.
Relocation plan: This plan (to simply move any toads that they happen to see after a day of
construction to some secret location) is absurdly uninformed and reflects the developer's lack of
knowledge of amphibian biology. Habitat loss is the problem for this species. If a toad could just
be moved somewhere else when development takes place, then I suspect the problem of global
amphibian declines wouldn't really exist.
If repatriation were to be successful, one would have to take eggs from a wetland and
put those eggs in a wetland that could positively support larval development and metamorphosis.
Additionally, the mosaic of ecotones in the uplands that I mentioned before would have to be in
place, and should encompass a 1000 m radius around the breeding site. You can't simply move a
Fowler’s toad somewhere else and expect it to live because they will home, and when they
attempt to home they likely will meet a road which usually means death for the toad. If the
relocation site is close to the site they were taken from, they will go back (or die trying). Unless
there is ample breeding and non-breeding habitat in the repatriation site, then there is a near 0%
chance of survival of translocated adults and subadult toads. Furthermore, the adult toads (if
relocated) will always attempt to return to wetlands near where they emerged from (natal ponds).
They do this based on celestial, olfactory, geographic and suspected magnetic cues. So even if
moving the toads out of the way of machinery at the end of the work day spares them for the
time being, we can consider those genes removed from the gene pool, as they will likely not
relocate a suitable breeding site.
If there is documented appropriate breeding and non-breeding habitat, then an
assessment would first need to take place: One would have to adequately estimate the existing
population size (with limited error) and then determine the carrying capacity of the parcel. If
there was a large enough capacity for that parcel then eggs would have to be introduced into the
system, not toads. Because these are R selected animals, we would need a lot of eggs, and it
would likely have to continue for quite a few years. Otherwise it is an uninformed crap shoot.
With some species a guesstimate might prove useful, but this is not sound enough to ensure the
survival of a federally protected subclimax community habitat specialist species. I am new to this
particular project, but from what I have seen and considering that the Fowler’s toad is federally
protected, the mitigation plan is a total embarrassment
General comments: There is nothing good that can come out of this proposed development.
Fowler’s toads are critical trophic links between freshwater and terrestrial ecosystems and are
protected for good reason. In the United States they are not a species of concern (yet). However,
after having read the literature and looking at historical records, it is clear that these toads are
subclimax community habitat specialists that are negatively impacted by development. There are
many areas throughout the Northeastern United States where populations have been extirpated.
There are areas in New York and New Jersey where repatriation efforts have failed. Even in my
study, which took place in a relatively well-protected area, I was able to see a clear negative
relationship between development and toad abundance. It is beyond me that in a country where
these animals are federally protected, that this sort of thing can go on. I think that it is fair to say
that as a society we could do without an additional condominium complex and shopping area.
However, the wanton loss of more wildlife is catastrophic because every time we needlessly
eliminate a group of animals it’s like we are burning down a library before we have even read the
books. Each animal population contains a wealth of molecular, evolutionary and ecological
information that can provide us with critical and meaningful insight into our own existence. That
being said, I commend “Save the Frogs” for taking on such a task and am proud of your efforts.
It helps me a great deal to know there are people like you speaking out for organisms that can't
speak for themselves.
Todd