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In Isle Royale National Park, heavy moose browsing over the past 100 years has suppressed the regeneration of many tree species, gradually resulting in a shift towards more open forests and savannas. By 1996, 16% of the forests at the southwestern end of Isle Royale had become savanna and another 20% of forests were starting to have canopy breakup. The changes in understory vegetation brought about by savanna formation have received little attention, even though the future of moose and wolf populations on Isle Royale is tied to these vegetation changes. This study examined the vegetation of savannas ranging in age (date since formation) from Key words: Isle Royale National Park, Poa pratensis, Picea glauca, herbivory, plant communities. Le broutement intensif des orignaux du Parc National de l'Isle Royale au cours des 100 dernieres annees a elimine la regeneration de plusieurs especes d'arbres, ce qui a graduellement resulte en un changement de vegetation vers des forets a couvert ouvert et des savanes. En 1996, 16% des forets du sud-ouest de l'Isle Royale etaient devenues de savanes et 20% de plus commencaient a montrer un morcellement du couvert forestier. Les changements de la vegetation de sous-etage amenes par la formation de la savane ont recu peu d'attention, meme si l'avenir des populations d'orignaux et de loups de l'Isle Royale est lie a ces changements de vegetation. Cette etude s'est penchee sur la vegetation des savanes d'ages varies (date depuis leur formation) allant de 10 ans a 80 ans afin d'examiner comment les changements de la flore du sol en fonction du temps, du morcellement du couvert forestier de la foret initiale a la prairie generalisee et finalement a un sous-climax zootique definissaient la << savane orignal-epinette >>. Des techniques d'ordination ont ete utilisees afin de decrire les communautes vegetales et d'identifier les variables environnementales qui influencent le developpement de la vegetation. Une regression multiplicative non parametrique a ete utilisee afin de predire comment ces variables influencaient les plants individuels et la structure a l'interieur des communautes. Les communautes vegetales presentaient des changements notables, allant d'herbes forestieres a des especes ruderales, particulierement des plantes non indigenes. Cette succession etait fortement influencee par le substrat rocheux et l'hydrologie sous-jacents modifiant les regimes d'humidite et les communautes vegetales. Picea glauca (Moench) Voss. et Poa pratensis L. competitionnaient dans une relation inhibitoire dynamique. Le premier favorisait les plantes forestieres alors que le deuxieme supplantait les autres vegetaux et favorisait les peuplements ouverts de graminees. Ces interactions changent dramatiquement le caractere des communautes vegetales des hautes terres de l'Isle Royale et elles auront des consequences trophiques importantes pour l'ile. [Traduit par la Redaction] Mots-cles : Parc National de l'Isle Royale, Poa pratensis, Picea glauca, herbivorisme, communautes vegetales., Introduction The impact of ungulate browsing in structuring plant communities is well known (Bergstrom 1992; Hobbs 1996; Cote et al. 2004). These impacts include changes to the vegetation structure and [...]

Mimulus guttatus (syn: Erythranthe guttata) is an important model organism in evolutionary ecology research. However, besides a few scattered reports of a single herbivore species at a time, there has only been one published list of herbivores that attack M. guttatus. I combined literature records as well as records from over five years of field surveys to include a range-wide list of species that attack M. guttatus. These records included plant populations from the native range in western North America and the non-native ranges in the United Kingdom and Eastern North America. I recorded over 86 species that consumed M. guttatus through its native and introduced ranges. In the native range, 77 species were found. In the UK, I reported 22 species of herbivores while in the eastern North America populations I recorded seven species feeding on M. guttatus. The native western North America range shared nine species with the UK range (mostly gastropods) and shared five herbivores with the eastern North America populations (mostly generalist mammal herbivores). I expect this list to grow as more studies focusing on plant–herbivore interactions in M. guttatus are published. I hope this list starts as a foundation for these future studies. [ABSTRACT FROM AUTHOR]

Mimulus guttatus is a widespread riparian plant native to western North America. Due to its wide distribution and phenotypic variation it has been the subject of many studies incorporating genetic information into ecological and life history evolution studies. Mimulus guttatus defends itself from herbivory with physical defenses (e.g. trichomes) as well as a suite of phytochemical defenses; phenylpropanoid glycosides (PPGs). Despite its importance as a model organism little has been done on the herbivores that feed on this plant. We used literature records as well as field observations to construct a list of the Lepidoptera that utilize M. guttatus as a food plant. Sixteen species of Lepidoptera within five families were recorded as feeding on M. guttatus. Six of these species are classified as generalist herbivores, while the rest have varying degrees of host plant specialization. [ABSTRACT FROM AUTHOR]