Differential effects of mammalian seed predators on the regeneration of five Papua New Guinean tree species and implications for sapling recruitment

Abstract

Abstract:Although herbivores may account for a significant source of seed and seedling mortality in many tropical tree species, plant species differ in their response to seed damage. Here we investigate the relative effects of seed predation on the regeneration of five tree species in a mid-elevation Papua New Guinean rain forest. Exclosure treatments and shade-house experiments were monitored from November 2004 to March 2006 to assess the differential effects of seed predation on seed viability and seedling growth. Results indicate that although seed predators attack all five focal species, they influence the seedling populations in two, Cerbera floribunda and Microcos grandiflora, and minimally affect the seedling populations of Terminalia impediens, Pandanus penicillus and Endiandra latifolia in the years measured. Predation and germination frequencies were compared to the abundance of focal species at several life stage classes to explore potential correlations between species-specific seed mortality patterns and life stage distributions. We found that the species-specific influence of mammalian seed predators correlated with abundance distributions in three life stages. Species with high survivorship after seed predator attacks displayed a significant decrease in abundance from the seedling-to-sapling transition, while those species with high seed mortality demonstrated relatively even distributions of seedlings, saplings and adults (> 10 cm dbh). These contrasting patterns suggest that differential seed predation effects on regeneration may play a key role in the recruitment of individuals to the sapling stage.

Biodiversity and Wild Fodder of Gorumara National Park in West Bengal, India

“…Seeds retrieved from the faecal matters of nonruminant herbivores and bird -droppings exhibited higher frequency of germination (70 -90%) than those gathered from forest floor (10 -40%). These seeds can be used for sapling production (Jones, Curran, Wright & Mack, 2008). Microscopic examinations revealed partial erosion and disintegration of outer coat of these seeds.…”

Seasonal Variation in the Fate of Seeds under Contrasting Logging Regimes

“…An understanding of these species' behavior as it pertains to seed loss is vital for predicting the potential consequences of habitat degradation on plant [28] and forest regeneration [29].…”

“…Different seed predators usually share the same environment and may even overlap in terms of seed species consumed [24] , but contrasting habitats could affect the behavior of seed consumers and alter seed dispersal and predation [25] – [27] . An understanding of these species' behavior as it pertains to seed loss is vital for predicting the potential consequences of habitat degradation on plant [28] and forest regeneration [29] .…”

História natural e ecologia de duas espécies de roedores simpátricas da tribo Oryzomyini (Cricetidae: Sigmodontinae) na floresta Atlântica

“…Com análoga ou maior importância acerca da dieta, estudos conduzidos através da análise do conteúdo estomacal e de experimento de oferecimento de recursos alimentares para organismos em cativeiro veem elucidando, ao longo de décadas, um conjunto de interações evolutivas, fisiológicas, comportamentais e conservacionistas (PINOTTI;TALAMONI et al, 2008;FORGET, 1991;MARTÍNEZ-GALLARDO, 1998;BREWER;REJMÁNEK, 1999;TERBORGH et al, 1993;IZAR, 2003;PAISE;MACHADO, 2006). HAMMOND, 1995;HOLL;LULOW, 1997;MAROM;SIMMS, 2001;NOTMAN;GOTCHOV, 2001;TERBORGH et al, 1993), e exercem papel importante na predação de sementes e plântulas MENDONZA;ORTIS, 2007;PINTO;SANTOS;TABARELLI, 2009;JONES et al, 2008;MENDOZA;PAINE;BECK, 2007;DEMATTIA;RATHCKE, 2004;IZAR, 2003;HALL, 2008;CADENASSO;PICKETT;MORIN, 2002), na dispersão de sementes e fungos micorrizos (HORN;KINDEL;HARTZ, 2008, PIMENTEL;BREWER, 2001;BREWER;REJMÁNEK, 1999;REDDELL;…”