Spider monkeys eating wood in Lacandona rainforest, Mexico.

<p>Panels show consumption of decayed wood from <i>Licania platypus</i> (A) and <i>Ficus</i> sp. (B), and live wood from young branches of <i>L. platypus</i> (C).</p

Average (± SD) content of macronutrients of different plant items in eight food species for spider monkeys (<i>Ateles geoffroyi</i>) in the Lacandona rainforest, Mexico.

a<p>With exception of this palm species, the rest of plant species represent “top” food species in the diet of spider monkeys in Lacandona <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0025070#pone.0025070-Chaves1" target="_blank">[24]</a>.</p>b<p>LW  =  live wood, DW  =  decayed wood, RF  =  ripe fruit, UF  =  unripe fruit.</p><p>Column headings: <i>n</i>  =  number of analyzed samples (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0025070#s2" target="_blank">Methods</a>), CC  =  estimated cellular content, CP  =  crude protein, TNC  =  total nonstructural carbohydrates, CF  =  crude fiber, CE  =  cellulose, HC  =  hemicellulose.</p

Nutritional composition of plant food species.

<p>Average (±SD) content of macronutrients (A,B) and minerals (C,D) of different plant items exploited by spider monkeys in Lacandona rainforest, Mexico. In each figure, nutrients are listed in decreasing order (from left to right). DW1 =  decayed wood of <i>L. platypus</i>; DW2 =  decayed wood of <i>Ficus</i> spp.; LW =  live wood; MF =  mature fruits; IF =  immature fruits. Bars sharing a letter are not significantly different (contrast tests, <i>P</i>>0.05).</p

Plant species exploited for live and decayed wood by spider monkeys (<i>Ateles geoffroyi</i>) in continuous forest and forest fragments in the Lacandona rainforest, Mexico.

<p>Species are listed by order of importance in the diet.</p>a<p>Only trees with ≥10 cm in diameter at breast height were considered (see further details in Chaves et al <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0025070#pone.0025070-Chaves1" target="_blank">[24]</a>). Although dead standing trees were not observed during the vegetation samplings, our observations through the home ranges of each monkey group indicated that their density was <i>ca.</i> 0.03 trunks/10,000 m² in both habitat types.</p>b<p>Index of preference. See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0025070#s2" target="_blank">Methods</a>.</p><p>Plant growth form (GF) and average percentage of total feeding time (%TFT). The %TFT for the three study sites is indicated in parenthesis.</p

Average (± SD) content of minerals of different plant items in seven food species for spider monkeys (<i>Ateles geoffroyi</i>) in the Lacandona rainforest, Mexico.

a<p>LW  =  live wood, DW  =  decayed wood, RF  =  ripe fruit, UF  =  unripe fruit.</p

Continuous forest sites and forest fragments studied in the Lacandona rainforest, Mexico.

<p>The location of each sleeping site of spider monkeys (dots) within the 30 ha of sampling area (gray shaded areas) area indicated. These areas were divided in 1-ha plots to estimate the spatial distribution of sleeping sites within each study area.</p

Lateral branches of a <i>Dialium guianense</i> sleeping tree (a), and different characteristics of latrines of spider monkeys (<i>Ateles geoffroyi</i>) in the Lacandona rainforest, Mexico: form of latrine (b), carpet of seedlings (c), seeds and fresh dung (d), spots of feces on the leaves of understory palms (e), and seeds and seedlings (f).

<p>Lateral branches of a <i>Dialium guianense</i> sleeping tree (a), and different characteristics of latrines of spider monkeys (<i>Ateles geoffroyi</i>) in the Lacandona rainforest, Mexico: form of latrine (b), carpet of seedlings (c), seeds and fresh dung (d), spots of feces on the leaves of understory palms (e), and seeds and seedlings (f).</p

Sites studied in the Lacandona rainforest, Mexico.

a<p>DNF = distance to nearest forest fragments; DCF = distance to continuous forest; YSF = years since fragmentation; CS = community size of spider monkeys.</p><p>(n/a) not applicable; (–) unavailable data.</p

Contagious Deposition of Seeds in Spider Monkeys' Sleeping Trees Limits Effective Seed Dispersal in Fragmented Landscapes

<div><p>The repeated use of sleeping sites by frugivorous vertebrates promotes the deposition and aggregation of copious amounts of seeds in these sites. This spatially contagious pattern of seed deposition has key implications for seed dispersal, particularly because such patterns can persist through recruitment. Assessing the seed rain patterns in sleeping sites thus represents a fundamental step in understanding the spatial structure and regeneration of plant assemblages. We evaluated the seed rain produced by spider monkeys (<i>Ateles geoffroyi</i>) in latrines located beneath 60 sleeping trees in two continuous forest sites (CFS) and three forest fragments (FF) in the Lacandona rainforest, Mexico. We tested for differences among latrines, among sites, and between forest conditions in the abundance, diversity (α-, β- and, γ-components) and evenness of seed assemblages. We recorded 45,919 seeds ≥5 mm (in length) from 68 species. The abundance of seeds was 1.7 times higher in FF than in CFS, particularly because of the dominance of a few plant species. As a consequence, community evenness tended to be lower within FF. β-diversity of common and dominant species was two times greater among FF than between CFS. Although mean α-diversity per latrine did not differ among sites, the greater β-diversity among latrines in CFS increased γ-diversity in these sites, particularly when considering common and dominant species. Our results support the hypothesis that fruit scarcity in FF can ‘force’ spider monkeys to deplete the available fruit patches more intensively than in CFS. This feeding strategy can limit the effectiveness of spider monkeys as seed dispersers in FF, because (i) it can limit the number of seed dispersers visiting such fruit patches; (ii) it increases seed dispersal limitation; and (iii) it can contribute to the floristic homogenization (i.e., reduced β-diversity among latrines) in fragmented landscapes.</p></div

Seed species diversity in spider monkeys' latrines located in continuous and fragmented forests in the Lacandona region, Mexico.

<p>From left to right, the panels show γ-, β-, and α-components of diversity at three spatial scales. The diversity of the landscape (γ_land; panel a) was partitioned into mean β- (b) and α- (c) diversities within the two forest conditions. The diversity within each forest condition (γ_forest; panel d) was partitioned into mean β- (e) and α- (f) diversities in the sites. Finally, the diversity within each site (γ_site; panel g) was partitioned into mean β- (h) and α- (i) diversities in latrines. Mean (± SE) α-diversities per forest condition, per site and per latrine is indicated in panels c, f and i, respectively (in panels f and i, significant differences are indicated with asterisks; * <i>P</i><0.05; ** <i>P</i><0.01; n.s. <i>P</i>>0.05). In all cases, we evaluated true diversities of order 0 (species richness), 1 (exponential of Shannon's entropy), and 2 (inverse Simpson concentration); however, in panel e we compared the relative compositional dissimilarity between forest conditions using the transformation of beta proposed by Jost (2007) for communities with different numbers of samples (CF: <i>n</i> = 2; FF: <i>n</i> = 3) (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0089346#s2" target="_blank">Materials and Methods</a>).</p