Jon Loman's research:
The rest of this page contains information on the listed subjects.
You can scroll or click to read it. Highlighted scientific names
link to photos and further information on the species.
Swedish brown frogs
There are three brown Swedish species of Rana;
R. temporaria and R. dalmatina.
The latter is rare and local
while the two former are widely spread over Sweden. They are my main
anuran study subjects. Both breed explosively in spring and the tadpoles
metamorphose after two to three months. They use both permanent and
temporary ponds. They hibernate in water or in the soil. The common toad
Bufo bufo, which is also subject of some of
my work, has a mode of life similar to the brown frogs. It is however much
less likely to breed in temporary ponds.
- Population regulation of frogs. Are frog
populations regulated by intraspecific competition? If so, does this operate
on the tadpole or adult stage? I have been conducting a series of
field experiments to investigate this. Two deals with tadpoles,
R. arvalis (report 21) and R. temporaria
(report 30) and one (in cooperation with Björn Lardner)
with adult frogs of both species (report 32).
This also includes studies of the effect of tadpoles on algae
abundance in the field (report 20).
The effect of food availability on female frog egg production has been studied
experimentally with Björn Lardner (report 28).
- Population dynamics, monitoring brown frog
populations. Beginning in 1989 I have monitored a varying
number of ponds. About 30 have been monitored during all years and
presently 120 are included. Notes are taken of Rana arvalis and R.
temporaria spawn clumps. I also monitor the ponds' water status during
summer to determine if metamorphosis can have taken place successfully.
A report (29) in Swedish is available.
- Tadpole growth and development in the field. I study different factors that affect tadpole survival
size and time for emergence for metamorphs. This includes density,
predators, temperature, pond drying and egg size. Some of this has also
been tested under controlled conditions where tadpoles are raised in 80 l
- Toads. Together with Thomas Madsen, I have
previously also studied mating strategies, survival and breeding site fidelity in the common toad,
B. bufo (publications 8, 13 and 39).
Publications, reports and manuscript
Most links to PDFfiles are found on the main publication publication list page.
- 1976. Growth in Rana temporaria and R. arvalis. Norw. J. Zool. 24:232-233.
- 1976. Fluctuations between years in density of Rana arvalis and R.
temporaria. Norw. J. Zool. 24:238
- 1978. Macro- and microhabitat distribution in Rana arvalis and R. temporaria
(Amphibia, Anura, Ranidae) during summer. J. Herp. 12:29-33.
- 1978. Growth of brown frogs Rana arvalis Nilss. and R. temporaria L. in
south Sweden. Ekol. Pol. 26:287-296.
- 1979. Food, feeding rates, and prey-size selection in juvenile and adult
frogs Rana arvalis Nilss. and R. temporaria L. Ekol. Pol. 27:581-601.
- 1981. Spacing mechanisms in a population of the common frog Rana temporaria
during the non-breeding period. Oikos 37:225- 227.
- 1984. Density and survival of Rana arvalis and R. temporaria. Alytes
- 1986. Reproductive tactics of large and small male toads Bufo bufo. Oikos
46:57-61. With Thomas Madsen.
- A survey of the reptiles and amphibians in Kora national Reserve. In:
Coe, M. and M. Collins (eds.). An Ecological inventory of the Kora national
reserve, Kenya. P. 235-241. With Michael Cheptumo, Thomas Madsen, Alex
Duff-MacKay, James Herbrard, and Damaris Rotich.
- Ecological studies on a moor frog population in southern Sweden.
Beih. Schriftenr. Naturschutz Landschaftspfl. Niedersachs. 19:139-140.
- 1988. Breeding by Rana temporaria; the importance of pond size and
isolation. Memo. Soc. Fauna Flora Fenn. 64:113-115.
- 1990. Frog density and distribution in a heterogeneous landscape - a
modelling approach. Ekol¢gia (CSSR) 9:353-360.
- 1991 Breeding pond fidelity in the common toad, Bufo bufo. With C. J.
Reading and T. Madsen. J. Zool. Lond. 225:201-211.
- 1994. Site tenacity, within and between summers, of Rana arvalis and Rana
temporaria. Alytes 12:15-29.
- 1995. Predation on Rana and Bufo tadpoles: Predator species and tadpole
size effects. Mem. Soc. Fauna Flora Fennica 71. With Björn Lardner.
- 1996. Övervakningsprogram för grodor i Skåne. [Monitoring program for frogs in Skåne].
Rapport från miljöövervakningen i Malmöhus län 7:1-48.
- 1997. Natural density regulation in tadpoles of the moor frog Rana
arvalis - preliminary report of a field experiment. For Proc. 8th General
Meeting of the Soc. Europ. Herp.
- 1999. Early metamorphosis in common frog Rana temporaria at risk of drying: an experimental demonstration. Amphibia-Reptilia 20:421-430.
- 2001. Effects of tadpole grazing on periphytic algae in ponds. Wetlands Ecol. Managmt. 9:135-139.
- 2001. Local variation in Rana temporaria egg and clutch size - adaptions to pond drying? Alytes 19:45-52.
- 2001. Intraspecific competition in tadpoles, does it matter in nature? A field experiment. Popul. Ecol. 43:253-263.
- 2002. When crowded, tadpoles (Rana arvalis and R. temporaria) fail to metamorphose early and thus fail to escape drying ponds. Herp. J. 12:21-28.
- 2002. Microevolution and maternal effects on tadpole Rana temporaria growth and development. J. Zool. 257:93-99.
- 2002. Rana temporaria metamorph production and population dynamics in the field. Effects of tadpole density, predation and pond drying. J. Nature Conserv. 10:95-107
- 2002. Temperature, genetic and hydroperiod effects on metamorphosis of brown frogs Rana arvalis and R. temporaria in the field. J. Zool. 258:115-129.
- 2003. Plastic response to pond drying in tadpoles Rana temporaria: tests of cost models. Evol. Ecol. Research. 5:179-194. With Didrik Clasesson.
- 2003. Growth and development of larval Rana temporaria: Local variation and countergradient selection. J. Herp. 37:595-602.
- 2003. Growth or reproduction? Resource allocation by female frogs Rana temporaria. With Björn Lardner. Oecologia. 137:541-546.
- 2003. Inventering av vanlig groda och åkergroda i Skåne 2002. Skåne i utvveckling 2003(19):1-26. PDF, 2.4MB
- 2004. Density regulation in tadpoles R. temporaria: A full pond field experiment. Ecology 85:1611-1618. PDF
- 2004. Loman, Jon and . Communal spawning in the common frog Rana temporaria - egg temperature and predation consequences. Ethology 110:665-680. PDF. With Pia Håkansson
- 2006. Does pond quality limit frogs Rana arvalis and R. temporaria in agricultural landscapes? A field experiment. J. Appl. Ecol. 43:690-700. PDF. With Björn Lardner
- 2007. Monitoring brown frogs Rana arvalis and R. temporaria in 120 south Swedish ponds 1989 - 2005. Mixed trends in different habitats. Biol. Conserv. 135:46-56.PDF. With Gunilla Andersson.
- 2008. Studies on the moor frog (Rana arvalis) in south Sweden. Journal of Field Herpetology, Supplementary volume, Laurenti publisher, Bielefeld, 2008.
- 2009. Does landscape and habitat limit the frogs Rana arvalis and Rana temporaria in agricultural landscapes? A field experiment. J. Appl. Herp. 10:227-236. PDF. With Björn Lardner.
- 2009. Primary and scondary phenology. Does it pay a frog to breed early? J. Zool. 279:64-70 PDF
- 2009. Density dependent growth in adult brown frogs Rana arvalis and R. temporaria - a field experiment. Acta Oecol. 35:824-830. PDF. With Björn Lardner.
- Loman, Jon and Björn Lardner. 2009. Density dependent growth in adult brown frogs Rana arvalis and R. temporaria - a field experiment. Acta Oecol. 35:824-830. PDF