Nutrient conservation strategies in native Andean‐Patagonian forests

Abstract

Abstract. Nutrient conservation in vegetation affects rates of litter decomposition and soil nutrient availability. Although resorption has been traditionally considered one of the most important plant strategies to conserve nutrients in temperate forests, long leaf life‐span and low nutrient requirements have been postulated as better indicators. We aimed at identifying nutrient conservation strategies within characteristic functional groups of NW Patagonian forests on Andisols. We analysed C‐, N‐, P‐, K‐ and lignin‐concentrations in mature and senescent leaves of ten native woody species within the functional groups: broad‐leaved deciduous species, broad‐leaved evergreens and conifers. We also examined mycorrhizal associations in all species. Nutrient concentration in mature leaves and N‐ resorption were higher in broad‐leaved deciduous species than in the other two functional groups. Conifers had low mature leaf nutrient concentrations, low N‐resorption and high lignin/N ratios in senescent leaves. P‐ and K‐resorptions did not differ among functional groups. Broad‐leaved evergreens exhibited a species‐dependent response. Nitrogen in mature leaves was positively correlated with both N resorption and soil N‐fertility. Despite the high P‐retention capacity of Andisols, N appeared to be the more limiting nutrient, with most species being proficient in resorbing N but not P. The presence of endomycorrhizae in all conifers and the broad‐leaved evergreen Maytenus boaria, ectomycorrhizae in all Nothofagus species (four deciduous, one evergreen), and cluster roots in the broad‐leaved evergreen Lomatia hirsuta, would be possibly explaining why P is less limiting than N in these forests.

Leaf strategies and soil N across a regional humidity gradient in Patagonia

“…The lack of a signiWcant relationship between humidity and N-resorption eYciency or proWciency supports the hypothesis that high N-resorption eYciency and low nutrient concentration in senesced leaves are not exclusive traits of plants from nutrient-poor habitats (Aerts and Chapin 2000;Carrera et al 2003;Diehl et al 2003). Both perennial grasses occupying the N-poorest habitats and trees occupying the N-richest habitats across the gradient showed the highest N-resorption eYciencies.…”

“…The wide range of precipitation and soil characteristics in Patagonia, between the rainforest in the west and the steppe in the east, constitutes one of the world's most striking vegetation gradients (Veblen and Lorenz 1988). In this study, we brought together previously published data for the Subantartic Phytogeographical Province (Diehl et al 2003;Satti et al 2003), the Patagonian Phytogeographical Province , the Patagonian Monte (Carrera et al 2003, and unpublished data from another seven sites of the Patagonian Phytogeographical Province. These data included 19 species of the 5 dominant life forms in 40 sites across a regional humidity (annual precipitation/annual potential evapotranspiration: P/PET) gradient, ranging from 0.19 to 4.2 in northern Patagonia (Table 1).…”

“…Mean annual temperatures range between 5.1 and 9.4°C (increasing from S to N), and the elevation varies from 560 to 1,320 m a.s.l. Soils are Andisols with a low degree of development, mainly Udivitrands of sandy to loam-sandy texture, characterized by a high capacity to stabilize organic matter, store water, buVer pH, and retain P (Diehl et al 2003;Alauzis et al 2004 The dry extreme of the gradient is characteristic of the Patagonian Phytogeographical Province (41°03Ј-45°35ЈS, 70°20Ј-71°45ЈW) and the southern portion of the Monte Phytogeographical Province (León et al 1998). Within the Patagonian Phytogeographical Province, two sampling sites were located in the Subandean District and seven in the Occidental District.…”

“…Soils are a complex of Typic Petrocalcids-Typic Haplocalcids (del Valle 1998). Contrasting life forms such as coniferous, broad-leaved evergreen, and broad-leaved deciduous trees coexist at humid temperate habitats (Walter 1985;Diehl et al 2003). Likewise, shrubs and perennial grasses are dominant contrasting life forms that coexist at dry habitats (West 1983;Bertiller et al 2005 …”

Implementation of Silvopastoral Systems under Nutrient Cycling in Secondary Vegetation in the Amazon

“…Bahamond et al (2012) reported that the quality of leaf litter is modified by changes in plant diversity proportion, which may have existed in SPSs. K and N had a lower return to the soil as they are translocated before leaf fall (Bahamond et al, 2012;Diehl et al, 2003).…”