Impact of abundance weighting on the response of seed traits to climate and land use

Abstract

Summary 1.Many studies have identified relationships between plant reproductive behaviour and environmental conditions. However, they have all been based on cross-species analysis and take no account of the relative abundance of species with vegetation. 2. Using two reproductive traits -seed mass and dispersal vector -as examples, a range of previously identified relationships were tested using both unweighted and weighted-by-abundance data collected from land-use transitions at 12 sites across Europe. 3. Seed mass was correlated positively with most measures of temperature (stronger relationships for unweighted data) and declined against measures of disturbance (stronger relationships with weighted data). It was not related consistently to measures of water availability. 4. There was some evidence that endozoochory was associated with damper environments, hoarding with drier ones and exozoochory with more fertile habitats. 5. Weighting reduced the slope of relationships between seed mass and environmental variables, possibly indicating that dominance within vegetation is determined by land use after the operation of a climatic filter. Fewer significant relationships were detected for weighted dispersal mechanisms compared to unweighted ones, indicating less difference of the dominants from other species with regard to this trait. 6. Synthesis . This analysis shows that weighting by abundance in the vegetation (compared to unweighted analysis) has a significant impact on the relationships between key species traits and a range of environmental parameters related to climate and land use, and that this impact was not consistent in its effects.

Contrasting trait responses in plant communities to experimental and geographic variation in precipitation

“…For example, drought tolerance is related to more conservative growth and resource use strategies (e.g. long leaf life span; Wright et al, 2004;Angert et al, 2007), water-conserving leaf traits (including high leaf N concentration; Wright et al, 2001) and larger seed masses (Baker, 1972;Leishman & Westoby, 1994;Pakeman et al, 2008). If these traits predict species' responses to precipitation, changes in community composition (including both relative abundance and species presence ⁄ absence) caused by altered precipitation should correspond with changes in community mean trait values.…”

“…Cover of woody species increased with increasing precipitation, which may cause light to become an increasingly important limiting resource. Under lowlight conditions large seeds are often favored (Bazzaz, 1979;Coomes & Grubb, 2003;Pakeman et al, 2008). Similarly, high N area may be an adaptation to low precipitation by allowing high water use efficiency in photosynthesis, but it is costly to maintain when water is not limiting (Reich et al, 1999;Wright et al, 2001Wright et al, , 2005.…”

Response of herbaceous vegetation functional diversity to land use change across five sites in Europe and Israel

“…these studies complement more numerous and advanced analyses of the response of community-level means to changing land use and other environmental conditions (reviewed by Lavorel et al, 2007; see also Pakeman et al, 2008Pakeman et al, , 2009), but still, little is known overall about how functional diversity changes in response to combined environmental gradients such as climate and disturbance , making it difficult to project the future structure and function of ecosystems. This question bears particular importance regarding grasslands, which are species-and functionally-diverse systems of primary importance to the global ecology, economy, and societies (Reid et al, 2005).…”

“…there is increasing evidence that SLA and other leaf traits associated with resource economy and in some, but not all cases, plant height respond to grassland management (Kahmen and Poschlod 2004;Louault et al, 2005;Díaz et al, 2007b;Garnier et al, 2007;Prach et al, 2007, and references therein). Seed weight responses, on the other hand, are inconsistent across sites (Pakeman, 2004;Pakeman et al, 2008). More intense management favors plants with more rapid resource acquisition (high SLA, low tissue and especially leaf density, high leaf nitrogen content), whereas abandonment or less intense management increases the dominance by more conservative strategies, and often, but not always, tall plants (Louault et al, 2005;.…”

Implementing the nitrogen cycle into the dynamic global vegetation, hydrology, and crop growth model LPJmL (version 5.0)

“…PFT-specific β root based on Schaphoff et al (2018b) and minimum and maximum leaf C : N ratios based on the TRY database (Kattge et al, 2011) with data from Kurokawa and Nakashizuka (2008), Garnier et al (2007), Penuelas et al (2010a, b), Fyllas et al (2009), Loveys et al (2003), Han et al (2005), Ordonez et al (2010), Atkin et al (1999), White et al (2000), Xu and Baldocchi (2003), Freschet et al (2010a, b), Laughlin et al (2010), Niinemets (2001Niinemets ( , 1999, Willis et al (2010), Baker et al (2009), Patiño et al (2009), Pakeman et al (2009Pakeman et al ( , 2008, Fortunel et al (2009), Cornelissen et al (1996Cornelissen et al ( , 1997Cornelissen et al ( , 2004, Quested et al (2003), Sardans et al (2008b, a), and Ogaya and Penuelas (2003). The C : N ratios for C 3 and C 4 grasses and crops are based on White et al (2000).…”