Disturbance and the elevation ranges of woody plant species in the mountains of Costa Rica

Abstract

Aim To understand how disturbance—here defined as a transient reduction in competition—can shape plant distributions along elevation gradients. Theory suggests that disturbance may increase elevation ranges, especially at the lower range limits, through reduced competitive exclusion. Nevertheless, to date this relationship remains unclear. Location Mountains of Costa Rica. Methods We compared the elevation range of woody stems over 10 cm dbh (“trees”) observed in plots along two transects spanning a range of elevations in secondary (regrowth) and old‐growth forest (409 and 249 species, respectively). We also estimated these elevation ranges using nationwide data. In addition, we examined the influence of stem size and plot scale basal area (as a measure of competition) on species elevation range limits in the two gradients. Results In general, tree species ranges increased with elevation. Species in the secondary forest had broader elevation ranges (100–318 m broader than species in the old‐growth forest; Wilcoxon: p‐value <.001). Also, in the secondary transect, individuals with greater diameters had broader elevation ranges than those observed as smaller trees (137 m broader; Kruskal–Wallis: p‐value = .03). The lower range limit of species occurred more frequently in plots with lower (vs. higher) basal area than expected by chance in both forest types. We also observed higher elevation upper limits in old growth, but not in secondary forests, with lower (vs. higher) basal area. Main conclusion Disturbance relaxes the constraints imposed by competition and extends effective elevation ranges of species, particularly those in secondary forest, to warmer and cooler climates (minimum increase equivalent to about 0.6–1.4°C). Thus, suitable disturbance may assist species persistence under climate change. We believe this is the first study indicating a consistent relation between disturbance and woody plant species distributions along elevation gradients.

Canopy openness modifies tree seedling distributions along a tropical forest elevation gradient

“…We maintained it for 18 months from February 2017 to August 2018. Temperature declines from an annual mean of 24°C to 10°C from low to high elevation, while precipitation follows a unimodal shape, from around 3400 mm a year at the lowest elevations, then rises until it peaks at almost 4200 mm at 1500 m and then declines again to around 2000 mm at the highest elevations (Muñoz Mazón et al 2019, 2020, Veintimilla et al 2019). The lowest parts of the elevation gradient are ‘premontane forest' a floristic transition between lowland and cloud forest.…”

“…Building on previous syntheses (Sheil 2016) and pilot studies (Muñoz Mazón et al 2019), these ideas on how forest gaps and clearings shape species ranges complement other studies that examined how climate and biotic interactions shape species distributions (Louthan et al 2015, Defossez et al 2016, Olsen et al 2016, Ettinger and HileRisLambers 2017, Putnam and Reich 2017. While it is well known that species tolerance to drought, low temperatures or frost can influence range limits (Ettinger et al 2011, Anderegg and HilleRisLambers 2015, Korner et al 2016, the role of plant interactions, such as competition and facilitation, are still debated (HilleRisLambers et al 2013, Scherrer et al 2020.…”

“…The characterization of these relationships is difficult due to the multiple factors that may influence distributions, including the complexity of natural disturbance regimes and multiple processes governing dispersal, establishment and survival (Sheil 2016). Experimental transplanting of tree seedlings under controlled conditions can clarify some effects of open areas versus forest canopy on the performance of this crucial life stage outside their typical elevation ranges (Muñoz Mazón et al 2019).…”

Evolutionary history of endangered and relict tree species Dipteronia sinensis in response to geological and climatic events in the Qinling Mountains and adjacent areas

“…However, montane orogenesis led to fluctuations in the climate in high‐altitude regions during the Quaternary period to severely impact the vegetation biota and genetic architecture by preventing population expansion and the migration of species with narrow thermal tolerance ranges (Avise, 2000; Knowles, 2001). Previous highly cited studies broadly explored the effects of tectonic uplifts and climatic oscillations on the diversification patterns of plants species in Europe, North America, and other regions, for example, in the Sierra Madre of Mexico (Bryson et al., 2012), the Andes (Hughes & Eastwood, 2006), Costa Rica (Muñoz et al., 2019), and the Himalayas (Xu et al., 2010; Yang et al., 2012). In China, many previous studies focused on this phenomenon in the complex and conspicuous topographical regions on the Qinghai–Tibet Plateau and adjacent areas (Ding et al., 2020; Wen et al., 2014; Xing & Ree, 2017).…”

“…In China, many previous studies focused on this phenomenon in the complex and conspicuous topographical regions on the Qinghai–Tibet Plateau and adjacent areas (Ding et al., 2020; Wen et al., 2014; Xing & Ree, 2017). It was recently reported that climate factors and montane orogenesis had strong and direct effects on montane forests, and they shaped the montane plant diversity (Li et al., 2020; Muñoz et al., 2019). However, another critical biodiversity hotspot in central China is the Qinling Mountains (QM), and the detailed evolutionary histories of plant species in this area are generally unknown (Liu et al., 2015; Wan et al., 2016; Zhang et al., 2015).…”