Bryophyte Species Diversity in Secondary Forests Dominated by the Introduced Species Spathodea campanulata Beauv. in Puerto Rico

Abstract

The introduced tree species Spathodea campanulata (Bignoniaceae) forms novel forests in Puerto Rico, these having emerged after the abandonment of fields in the mid‐20th century and resulting in forests with a new species composition. We assessed bryophyte species richness in these novel forests and sought correlations with geological substrate, past land use, forest edge and patch area, forest structure, elevation, microhabitat diversity, tree species richness, and microclimatic conditions. Transects were established (edge and forest interior) in nine moist forest patches dominated by Spathodea in north‐central Puerto Rico. These Spathodea forest patches ranged from 0.6 to 9 ha. ANOVA, Chi‐square, correlation, and cluster analyses were used in data analyses. We found 57 bryophyte species. There was a significant difference in bryophyte richness among patches. Those on karst exhibited highest bryophyte richness due to microhabitat diversity, past land use, and shorter hydroperiods. Alluvial sites scored lowest in bryophyte species richness, and forest structure was important for bryophyte communities on these sites. Significant differences in temperature, relative humidity, and light intensity were observed between edge and forest interior. These appeared important for establishing bryophyte species cover but not richness and composition. Microhabitat diversity, patch area, and forest age were more related to bryophyte species richness than elevation, exposed edge, and tree species richness, regardless of geologic substrate. Collectively, Spathodea patches were similar to mature forests on the Island with respect to bryophyte species richness and composition. Novel Spathodea forests have conservation value due to their habitat suitability for bryophyte communities.

Conflicting values: ecosystem services and invasive tree management

“…For example, removal of invasive trees often results in invasion by non-native grasses, which in many cases can be more problematic than the original weed (Richardson et al 2000;Rutherfurd 2010;Dickie and Peltzer, unpublished data). At the same time, invasive trees can also serve to facilitate ecosystem restoration and regeneration of native vegetation (Ewel and Putz 2004;Fischer et al 2009;Pérez et al 2012;Becera and Montenegro 2013), suggesting that delayed or staggered removal could enhance long-term ecological outcomes (e.g. Ruwanza et al 2013).…”

Geographic distribution and spatial attributes of African tulip tree forests in north-central Puerto Rico: Implications forsocial-ecological resilience

“…This introduced tree species readily invades deforested and abandoned lands in the moist regions of Puerto Rico, which are typically covered with introduced and invasive forage grasses (e.g., Megathyrsus maximus and Sorghum halepense) that hinder the establishment of native early-successional secondary forest tree species such as Cecropia scheberiana (Silander, 1979;Aide et al, 2000;Lugo, 2004). The novel forests dominated by Spathodea harbor many other tree species, floral and faunal assemblages that are mostly native, have similar structure compared to native forests and have an equal higher capacity for biomass, carbon and nutrient storage compared to other forests in Puerto Rico (Abelleira et al, 2010;Lugo et al, 2012a;Pérez et al, 2012). In addition, the high nutrient content of Spathodea leaves appears to combine with high litterfall and decomposition rates to speed up nutrient cycling to the forest floor and soils, potentially enhancing the establishment and growth of trees growing in the forest understory (Abelleira, 2011;Lugo et al, 2011;Lugo and Abelleira 2018).…”