2010). Secondary seed dispersal by dung beetles in a Colombian rain forest: effects of dung type and defecation pattern on seed fate. Abstract:In rain forests the fate of seeds defecated by mammals is often affected by dung beetles, but these effects can vary with mammal species. In a Colombian forest, differences in Scarabaeinae assemblages attracted to spider monkey (Ateles hybridus) and howler monkey (Alouatta seniculus) defecations were assessed. In total, 791 beetles of 35 species were captured. Mean number of individuals was similar for both dung types; mean number of species was higher for Alouatta traps. The effects of dung type (Alouatta vs. Ateles) and defecation pattern (clumped vs. scattered) on the fate of 220 Rollinia edulis (Annonaceae) seeds were determined. Burial by beetles occurred for 61% of the seeds (mean depth 2.6 cm). Seeds in Alouatta dung and in clumped defecations had higher burial rates. Horizontal movement (mean 11 cm) occurred for 80% of the seeds; no significant effects of experimental factors were detected. Survival was higher for buried vs. surface seeds. In a separate experiment, no differences were detected between dung types in the proportion of seeds buried by beetles. Changes in dung texture might have been responsible for the contrasting results. When assessing the effectiveness of an endozoochorous plant-mammal interaction, secondary dispersal by dung beetles should be addressed too.

Recent evidence has shown that primates worldwide use agroecosystems as temporary or permanent habitats. Detailed information on how these primates are using these systems is scant, and yet their role as seed dispersers is often implied. The main objective of this study was to compare the activity, foraging patterns and seed dispersal role of black howler monkeys (Alouatta pigra) inhabiting shaded cocoa plantations and rainforest in southern Chiapas, Mexico. We gathered data on three monkey groups living in shaded cocoa plantations and three groups living in rainforest, using focal sampling, and collecting fecal samples. General activity and foraging patterns were similar in both habitats, with the exception that monkeys in the cocoa habitat spent more time feeding on petioles. Monkeys in shaded cocoa plantations dispersed 51,369 seeds (4% were seeds ≥3 mm width) of 16 plant species. Monkeys in the rainforest dispersed 6,536 seeds (78% were seeds ≥3 mm width) of 13 plant species. Our data suggest that the difference between habitats in the proportion of large versus small seeds dispersed reflects differences in fruit species abundance and availability in cocoa versus forest. Mean seed dispersal distances were statistically similar in both habitats (cocoa = 149 m, forest = 86 m). We conclude that the studied cocoa plantations provide all elements necessary to constitute a long-term permanent habitat for black howler monkeys. In turn, howler monkeys living in these plantations are able to maintain their functional role as seed dispersers for those native tree and liana species present within their areas of activities.

No abstract

Dung beetles are extensively used as a focal taxon in tropical forests. Yet, information for most of their ecological functions comes from other systems. We present results from a field experiment in a tropical rain forest showing that dung beetle activity increases foliar phosphorus concentration in seedlings of the tree Brosimum lactescens. Our results open new lines of research to assess the multiple effects that dung beetles may have on rain forest plants.

Howler monkeys are among the most studied primates in the Neotropics, however, behavioral studies including estimation of food availability in Andean forests are scarce. During 12 months we studied habitat use, behavior, and feeding ecology of two groups of red howler monkeys (Alouatta seniculus) in an isolated fragment in the Colombian Andes. We used a combination of focal animal and instantaneous sampling. We estimated fruit production (FP) using phenology transects, and calculated young leaf abundance by observing marked trees. The home range area used by each group was 10.5 and 16.7 ha and daily distances traveled were 431 ± 228 and 458 ± 259 m, respectively. We found that both groups spent most of their time resting (62-64%). Resting time did not increase with leaf consumption as expected using a strategy of energy minimization. We did not find a relationship between daily distances traveled and leaf consumption. However, howlers consumed fruits according to their availability, and the production of young leaves did not predict feeding time on this resource. Overall, our results are similar to those found on other forest types. We found that despite limited FP in Andean forests, this did not lead to a higher intake of leaves, longer resting periods, or shorter traveling distances for red howlers.

Mexico has one of the richest tropical forests, but is also one of the most deforested in Mesoamerica. Species lists updates and accurate information on the geographic distribution of species are necessary for baseline studies in ecology and conservation of these sites. Here, we present an updated list of the diversity of amphibians and reptiles in the Lacandona region, and actualized information on their distribution and conservation status. Although some studies have discussed the amphibians and reptiles of the Lacandona, most herpetological lists came from the northern part of the region, and there are no confirmed records for many of the species assumed to live in the region. After reviewing databases of scientific collections and published herpetological lists, and adding new information from our 2007 to 2013 inventories of the southeastern Lacandona rainforest, we recorded 124 species (89 reptiles and 35 amphibians) for the region. Nine amphibians (25.7%) and 2 (2.2%) reptiles are endemic to the Mayan forest (from the Lacandona, in Mexico, to the Mayan Mountains in Belize). Four amphibians and three reptiles appeared to be restricted to the Montes Azules Biosphere Reserve, suggesting that they are particularly vulnerable to habitat loss and degradation. On average, the region shares less than 60% of the species with neighboring Mexican tropical forests (e.g., Las Choapas region and Los Tuxtlas, Calakmul, and Sian-Ka'an Biosphere Reserves). Of the herpetofauna evaluated, the Mexican government threatened species list (NOM 059) indicates that seven species (20%) are under a risk category, while the IUCN indicates that only seven species (10.1%) are at risk. Our findings indicate that Lacandona is of great importance for the conservation of the Mesoamerican herpetofauna. Nevertheless, increasing deforestation levels add further uncertainties to the maintenance of amphibians and reptiles among other vertebrates in the region.

No abstract

Primates are important seed dispersers in natural ecosystems and agro-ecosystems, but the latter scenario remains under-studied. The degree to which primates favour plant regeneration greatly depends on post-dispersal processes. The main objective of this study was to compare patterns of seed/seedling fate and seedling recruitment in two habitats of the black howler monkey (Alouatta pigra Lawrence 1933), rustic cocoa and rain forest, and two types of seed-deposition locations, monkey latrines and control locations. Field experiments were carried out within the non-overlapping home ranges of six monkey groups, three in cocoa and three in forest. Seed and seedling fates were assessed for one focal tree species, Brosimum lactescens. The probabilities of seed survival (0.52), germination (0.72), seedling establishment (0.73) and early seedling survival (0.38) were not affected by habitat or seed-deposition location. Late seedling survival was similar in the two habitats but was higher in control locations (0.22) than in latrines (0.09). In cocoa, 4641 seedlings of 59 species were recorded, in forest 3280 seedlings of 68 species. Seedling recruitment was similar in both habitats, but latrines had higher densities than control locations. The importance of agro-ecosystems with low management intensity for the maintenance of ecological processes in anthropogenic landscapes is discussed.