Edge effects in recruitment of trees, and relationship to seed dispersal patterns, in cleared strips in the Peruvian Amazon

Abstract

We investigated the spatial pattern of tree recruitment 15 years after clear‐cutting in two logged strips in the Peruvian Amazon, focusing on differences between seed dispersal modes and cohorts, and relating these to spatial patterns of seed dispersal in the years immediately following clearing. Most trees that recruited in logged strips belonged to taxa dispersed by birds or nonvolant mammals, with smaller numbers dispersed by bats or wind. Seed dispersal patterns differed, with few mammal‐dispersed seeds reaching strips, bird‐dispersed seeds more abundant near the forest edge than strip centers, and bat‐ and wind‐dispersed seeds more evenly distributed. However, this pattern was not reflected in the tree recruits, except in the deferment cut half of strip 2. Different dispersal modes were differentially represented in different cohorts; for example, in strip 1 bird‐dispersed trees predominated in early cohorts, while trees dispersed by nonvolant mammals predominated in later cohorts. Our finding that trees dispersed by mammals (which disperse the majority of commercial trees in Amazonia) successfully regenerate from seed in the interior of logged strips highlights the value of maintaining these animals in forest management systems.

Responses of Tropical Bats to Habitat Fragmentation, Logging, and Deforestation

“…Mostly using fecal analysis or seed traps, numerous studies in various human-modified landscapes across the Neotropics have documented the quantity and diversity of seeds carried by bats (mostly Carollia spp., Sturnira spp., Artibeus spp.) into a diverse range of disturbed habitats including pastures, agricultural areas, coffee plantations, and secondary forests (Medellín and Gaona 1999;Galindo-González et al 2000;García et al 2000;Aguiar and Marinho-Filho 2007;Hanson et al 2007;Wieland et al 2011;Castro-Luna and Galindo-González 2012b;García-Estrada et al 2012;García-Morales et al 2012;Gorchov et al 2013). Voigt et al (2012) showed that bats of the genus Carollia were likely to carry seeds from midsuccessional forest into adjacent primary forest, suggesting that directionality of seed transfer between disturbed areas and undisturbed forest may change with forest recovery.…”

Deforested habitats lack seeds of late‐successional and large‐seeded plant species in tropical montane forests

“…Instead, changes in seed size are probably related to the lack of large forest bird species, transporting seeds into deforested areas (Gorchov et al. , ; Moran et al. ).…”

“…) may lead to an uneven distribution of seed traits in deforested habitats (Gorchov et al. ). Consequently, seed dispersal limitation can affect the diversity of functional seed traits (Galetti et al.…”

“…Changes in the functional structure of frugivorous bird communities moving toward forest edges and deforested habitats (Menke et al 2012;Saavedra et al 2014) may lead to an uneven distribution of seed traits in deforested habitats (Gorchov et al 2012). Consequently, seed dispersal limitation can affect the diversity of functional seed traits (Galetti et al 2011) and the composition of seed traits in the seed bank of regenerating habitats (Helsen et al 2012).…”

Do riparian forest strips in modified forest landscapes aid in conserving bat diversity?

“…We focus our study on bats as a biodiversity model system because they serve as good indicators of ecosystem health due to their species diversity, have varied life histories and morphologies, and are important in providing a variety of ecological services (Bennett, Radford, & Haslem, 2006;Castro-Luna, Sosa, & Castillo-Campos, 2007;Fenton & Rautenbach, 1998;Hein, Castleberry, & Miller, 2009). Bats play key roles in forest regeneration and ecosystem dynamics through the ecological services they provide combined with their high mobility and use of a variety of habitats (Gorchov et al, 2013;Kasso & Balakrishnan, 2013).…”