Agriculture, Ecosystems and Environment 142 (2011) 280–290 Contents lists available at ScienceDirect Agriculture, Ecosystems and Environment journa l h o me pa ge: www.elsevier.com/locate/agee Differential influence of land use/cover change on topsoil carbon and microbial activity in low-latitude temperate forests Ana María Gamboa, Leopoldo Galicia ∗ Departamento de Geografía Física, Instituto de Geografía, Universidad Nacional Autónoma de México, Circuito Exterior S/N, Ciudad Universitaria, México, D.F., C.P. 04510, Mexico a r t i c l e i n f o Article history: Received 18 October 2010 Received in revised form 18 May 2011 Accepted 23 May 2011 Available online 16 June 2011 Keywords: Soil carbon Land use/cover change Andosols Microbial biomass carbon Soil enzymatic activity Basal soil respiration a b s t r a c t Land use/cover change (LUCC) is one of the main factors that control the terrestrial carbon (C) cycle. We examined the effect of LUCC on topsoil C, microbial biomass C (MBC) and microbes mediated processes related to C circulation and their relationship with other soil properties in low-latitude mountain temper- ate forests. We selected three sites in the northwest of Cofre de Perote volcano (Mexico) in an altitudinal gradient (piedmont, lower mountain slope and mid slope). At each site we selected three land use/cover units as a chronosequence: (1) reference forest, (2) agriculture, and (3) regeneration/reforestation. At each of the nine land use/cover units we collected five soil samples (0–10 cm) for determination of total soil C (C T ), MBC, basal soil respiration, metabolic quotient and enzymatic activity (-glucosidase and dehydrogenase activities, and fluorescein diacetate hydrolysis). Forest conversion to agriculture dimin- ished the C T concentration in the three sites (72%, 20% and 61% on piedmont and lower and mid slopes, respectively); however, C T content only decreased at piedmont soils. The vulnerability of piedmont soils to C loss due to this LUCC is higher than in mountain slope Andosols. Furthermore, this LUCC differentially affected absolute MBC (i.e. on dry soil base) and specific MBC (i.e. on C T base). Specific site environmental conditions and MBC reference levels seem to determine the sensitivity of MBC to LUCC. Forest recovery after agricultural use only caused an increase of C T concentration (55%) in piedmont soils. There are dif- ferent controls of soil C storage and circulation in the altitudinal gradient studied. At piedmont and mid mountain slope soils MBC, its activity, nutrient availability and physical soil properties play an important role; meanwhile, at lower mountain slope Andosols mineralogical properties, specifically the Al–humus complexes exerts the main control. © 2011 Elsevier B.V. All rights reserved. 1. Introduction The global carbon (C) balance is affected by land use/cover change (LUCC) (Amundson, 2001). It has been suggested that, at scales of decades to centuries, LUCC is the main factor determin- ing soil organic carbon (SOC) storage (Scott et al., 2002). The CO 2 emissions linked to LUCC are the second-largest anthropogenic CO 2 source (1.5 ± 0.7 Pg C yr -1 for the period 1990–2005; Le Quéré et al., 2009). Soil is the largest C pool in terrestrial ecosystems, and SOC is estimated to be 1462–1548 Pg in the upper 1 m (Batjes, 1996). The C pool of temperate forest soils is 153 Pg, which is 22% of the soil C pool in the soils of the forest zones of the world (Prentice, 2001). The conversion of forests to croplands causes a depletion of soil C pools by ∼22% (Murty et al., 2002). However, these losses could be in part reversed through regrowth of secondary vegeta- tion or reforestation (Guo and Gifford, 2002). This reduction of soil C has been related to increases in the rates of soil organic matter ∗ Corresponding author. Tel.: +52 55 56230222x45505; fax: +52 55 56162145. E-mail address: lgalicia@igg.unam.mx (L. Galicia). (SOM) mineralization, modification of the amount and quality of organic residues and their redistribution, changes in soil structure and increases in erosive processes (Post and Kwon, 2000; Guo and Gifford, 2002; Murty et al., 2002). Since the high decomposition rate of microbial biomass C (MBC), it is regarded as good indicator of the impacts of LUCC (Gregorich et al., 1997). Furthermore, the processes related to SOC circulation (e.g. mineralization and enzy- matic activity) have been also suggested as indicators of the effects of LUCC on biological activity and soil quality because of their fast response to changes of use and management (Bandick and Dick, 1999; Haynes, 2005). Soil C pool and turnover depend on the interaction of numer- ous factors including climate, parent material, topography and vegetation, as well as physical, chemical and biological soil prop- erties (Post and Kwon, 2000; Tan et al., 2004). Soil types differ in their C storage and Andosols, pertinent to the present study, have the second largest C pool (31 kg m -2 ; Eswaran et al., 1993) after Histosols. The high C storage of Andosols has been attributed to enhanced SOM stabilization due to the formation of organo- metallic complexes with short-range-order minerals (Shoji et al., 1993). Andosols organic matter residence time is high and the cir- 0167-8809/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.agee.2011.05.025