title: The response of forest plant regeneration to temperature variation along a latitudinal gradient.
abstract: OBJECTIVE
  The response of forest herb regeneration from seed to temperature variations across latitudes was experimentally assessed in order to forecast the likely response of understorey community dynamics to climate warming.
  
  
  METHODS
  Seeds of two characteristic forest plants (Anemone nemorosa and Milium effusum) were collected in natural populations along a latitudinal gradient from northern France to northern Sweden and exposed to three temperature regimes in growth chambers (first experiment). To test the importance of local adaptation, reciprocal transplants were also made of adult individuals that originated from the same populations in three common gardens located in southern, central and northern sites along the same gradient, and the resulting seeds were germinated (second experiment). Seedling establishment was quantified by measuring the timing and percentage of seedling emergence, and seedling biomass in both experiments.
  
  
  RESULTS
  Spring warming increased emergence rates and seedling growth in the early-flowering forb A. nemorosa. Seedlings of the summer-flowering grass M. effusum originating from northern populations responded more strongly in terms of biomass growth to temperature than southern populations. The above-ground biomass of the seedlings of both species decreased with increasing latitude of origin, irrespective of whether seeds were collected from natural populations or from the common gardens. The emergence percentage decreased with increasing home-away distance in seeds from the transplant experiment, suggesting that the maternal plants were locally adapted.
  
  
  CONCLUSIONS
  Decreasing seedling emergence and growth were found from the centre to the northern edge of the distribution range for both species. Stronger responses to temperature variation in seedling growth of the grass M. effusum in the north may offer a way to cope with environmental change. The results further suggest that climate warming might differentially affect seedling establishment of understorey plants across their distribution range and thus alter future understorey plant dynamics.
authors.affiliation: Laboratory of Forestry, Ghent University, Geraardsbergsesteenweg 267, Melle-Gontrode, Belgium. Pieter.DeFrenne@UGent.be
authors.forename: Pieter
authors.initials: P
authors.lastname: De Frenne
authors.forename: Bente J
authors.initials: BJ
authors.lastname: Graae
authors.forename: Jörg
authors.initials: J
authors.lastname: Brunet
authors.forename: Anna
authors.initials: A
authors.lastname: Shevtsova
authors.forename: An
authors.initials: A
authors.lastname: De Schrijver
authors.forename: Olivier
authors.initials: O
authors.lastname: Chabrerie
authors.forename: Sara A O
authors.initials: SA
authors.lastname: Cousins
authors.forename: Guillaume
authors.initials: G
authors.lastname: Decocq
authors.forename: Martin
authors.initials: M
authors.lastname: Diekmann
authors.forename: Martin
authors.initials: M
authors.lastname: Hermy
authors.forename: Thilo
authors.initials: T
authors.lastname: Heinken
authors.forename: Annette
authors.initials: A
authors.lastname: Kolb
authors.forename: Christer
authors.initials: C
authors.lastname: Nilsson
authors.forename: Sharon
authors.initials: S
authors.lastname: Stanton
authors.forename: Kris
authors.initials: K
authors.lastname: Verheyen
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology; D031883:Anemone / Q000254:growth & development / Q000502:physiology*; D018533:Biomass; D002980:Climate; D005602:France; D005843:Geography; D018525:Germination / Q000502:physiology*; D006109:Poaceae / Q000254:growth & development / Q000502:physiology*; D036226:Seedlings / Q000254:growth & development / Q000502:physiology; D012639:Seeds / Q000254:growth & development / Q000502:physiology; D013548:Sweden; D013696:Temperature; D013997:Time Factors