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Usefulness of volunteer data to
measure the large scale decline of
“common” toad populations
By: Anna Bonardi, G. Francesco Ficetola et al.
The common toad (Bufo bufo) is a
widespread species, inhabiting large
areas of Europe and Western Asia. Data
suggested that this toad is declining
in some European countries, but it is
difficult obtaining quantitative measures
of demographic trend for such a largerange
species. We used data collected by
volunteers saving amphibians on the road to
evaluate the trend of common toad in Italy
across broad spatial and temporal scales.
We collected data on 33 toad populations
across Northern and Central Italy for
the period 1993-2010. We used two
approaches (meta-analysis; analysis of
average change in population size) to
evaluate the overall demographic trend.
We incorporated measures of volunteer
sampling effort into analyses, to take into
account changes in detection probability
and to obtain more reliable information.
Toad abundance significantly declined in
the last decade. From 2000 to 2010, 70% of
populations showed a strong decline, and only
10% increased. Trends were heterogeneous
among populations, but taking into account
sampling effort reduced heterogeneity
by 40%. We detected a 76% cumulative
average decline of toad populations,
despite an increasing mean sampling effort.
It is difficult to identify the causes of
such a widespread decrease; therefore
we dread that the decline will continue in
the next future. The common toad occurs
in many modified habitats, nevertheless
several factors may negatively affect
its populations, including habitat loss,
fragmentation, chytridiomycosis, road
mortality, pollution and climate change;
joint effects of multiple factors are also
possible. Future studies are required
to identify the drivers of toad decline.
Common toad (Bufo bufo). Photo: G. Francesco Ficetola
Full article: Bonardi, A. et al. (2011).
Usefulness of volunteer data to
measure the large scale decline
of “common” toad populations.
Biological Conservation, 144: 2328–
2334. (anna.bonardi@unimib.it)
Managing Pond-Breeding Anurans
in the Selectively Harvested
Forests of Coastal New South
Wales, Australia
Francis L. Lemckert
series of protective prescriptions
A have been implemented to minimize
the impacts on populations of anurans
present in areas of selective forestry
operations in coastal New South Wales.
These prescriptions result in the retention
of a range of undisturbed patches of habitat
known or perceived to be of importance to
Telemetry work has indicated that most species in
these forests, such as the threatened heath frog (Litoria
littlejohni) use non-breeding habitats located well away
from their breeding ponds. Photo: Francis Lemckert.
their survival. I reviewed the information
available on the ecology of anurans in
these forests and the known impacts of
forestry operations in order to assess the
effectiveness of these prescriptions in
protecting pond breeding species. Research
has indicated that the protective buffer
zones applied around ponds are likely to
provide a significant level of protection
to breeding individuals and the aquatic
environment. Studies of the activity
patterns of anurans demonstrate that nonbreeding
individuals generally use forest
areas falling outside of pond-side buffers.
These non-breeding habitats are afforded
some protection through the retention of
hollow-bearing habitat trees, identified
important habitat patches and movement
corridors, but significant areas can still be
disturbed, and often severely, by logging
machinery. Studies assessing the impacts of
logging on Australian anuran populations
indicate that they are generally robust to
the effects of logging, with only habitat
specialists showing obvious, but still
limited declines. I postulate that anurans in
this region are pre-adapted to coping with
the changes produced by selective logging
because they have evolved in a highly
changeable environment. I conclude that
current forestry practices are unlikely to
have significant long-term negative effects
if current protective measures are retained
to protect identified sensitive habitats.
However, if more intensive logging is
adopted, a well planned adaptive monitoring
program should be implemented to
determine if this situation remains the case.
Full article: Lemckert, F.L. (2011)
Managing pond breeding anurans in
the selectively harvested forests of
coastal New South Wales, Australia.
For. Ecol. Manage. 262:1199–1204.
Do Tadpoles Affect Leaf
Decomposition in Neotropical
Streams?
By Scott Connelly, Catherine M. Pringle, Matt R.
Whiles, Karen R. Lips, Susan Kilham, & Roberto
Brenes
Of the relatively few studies that have
examined consequences of amphibian
declines on stream ecosystems, virtually all
have focused on changes in algal-based food
webs. Thus, little is known about potential
tadpole effects on leaf decomposition.
We experimentally compared leaf litter
decomposition dynamics in two Neotropical
streams: one with an intact community
of tadpoles (with frogs) and one where
tadpoles were absent as a result of a
catastrophic extirpation event associated
with a fungal pathogen, Batrachochytrium
dendrobatidis (frogless). The stream
with tadpoles contained a complete
assemblage of larval anurans (23 species)
and we identified five species of glass frog
(Centrolenidae) tadpoles that were patchily
distributed but commonly associated with
leaf detritus and organic sediments in
pools. We recorded densities of centrolenid
tadpoles (0-318 tadpoles m -2 ) and their
biomass-specific excretion rates (0.063
± 0.018 ug N mg tadpole -1 h -1 ). We
experimentally excluded tadpoles from
single-species leaf packs incubated over a
40-day period in both the with frogs and the
frogless streams. In the stream with frogs,
Centrolene prosoblepon and Cochranella
albomaculata tadpoles were patchily
distributed in control leaf packs (0.0 – 33.3
m -2 ). We observed a trend of higher fungal
biomass (marginally significant; P < 0.10)
in leaf packs containing tadpoles in control
treatments versus exclusion treatments in
the stream with frogs (56.9 vs. 42.7 mg C g -1
FrogLog Vol. 98 | September 2011 | 43