Ecological networks describe the interactions between species, the underlying structure of communities, the function and stability of ecosystems. To date, network analyses have been extensively applied to understand mutualistic and antagonistic interactions, but few have examined commensal interactions, particularly in neotropical regions. The inselbergs of southeastern Brazil are considered one of the three most important regions in the world in terms of terrestrial species diversity and endemism but are poorly studied. In this study, we constructed the first epiphyte-phorophyte commensalistic network in a Brazilian inselberg and examined its structure and robustness to simulated species loss. A total of 138 phorophyte individuals belonging to eight species were observed in 20 2 m × 50 m transects, interacting with 5,039 individuals of vascular epiphytes belonging to 85 species. The epiphyte-phorophyte network structure exhibited a low degree of specilization (H2'), low connectance and robustness; when the most connected phorophyte species were sequentially removed the number of secondary extinctions was high, based on robustness metrics. One generalist phorophyte, Pseudobombax sp. nov., was particularly important, hosting a high number of epiphyte species. A single phorophyte individual of Pseudobombax supported 46% of the total richness of the epiphyte community studied. Our results demonstrate that the richness and abundance of epiphytes were correlated with phorophyte size (as mensured by the DBH, diameter at breast height), probably due to increased habitat area and the time available for colonization. We conclude that phorophyte size and species identuty are important factors for predicting the structure of epiphyte-phorophyte interaction networks. 2We discuss the conservation implications of phorophyte loss and secondary extinctions of epiphytes in Atlantic Forest inselbergs.
Hybridization is continually documented in primates, but effects of natural and anthropogenic hybridization on biodiversity are still unclear and differentiating between these contexts remains challenging in regards to primate evolution and conservation. Here, we examine hybridization effects on the mitochondrial DNA (mtDNA) control region of Callithrix marmosets, which provide a unique glimpse into interspecific mating under distinct anthropogenic and natural conditions. DNA was sampled from 40 marmosets along a 50-km transect from a previously uncharacterized hybrid zone in NE Brazil between the ranges of Callithrix jacchus and Callithrix penicillata. DNA was also collected from 46 marmosets along a 30-km transect in a hybrid zone in Rio de Janeiro state, Brazil, where exotic marmosets appeared in the 1980s. Combining Callithrix DNA sampled inside and outside of these hybrid zones, phylogenetic and network analyses show C. jacchus and C. penicillata being parental species to sampled hybrids. We expand limited Callithrix population genetics work by describing mtDNA diversity and demographic history of these parental species. We show ancient population expansion in C. jacchus and historically constant population size in C. penicillata, with the latter being more genetically diverse than the former. The natural hybrid zone contained higher genetic diversity relative to the anthropogenic zone. While our data suggest hybrid swarm formation within the anthropogenic zone due to removed physical reproductive barriers, this pattern is not seen in the natural hybrid zone. These results suggest different genetic dynamics within natural and anthropogenic hybridization contexts that carry important implications for primate evolution and conservation.
Common marmosets, one of the smallest anthropoid primates, have a relatively high reproductive rate, capable of producing twins or triplets twice per year. Growth and development of infants is relatively rapid, and lactation is relatively short at less than 3 months. Although mean values for the proximate composition (dry matter, protein, fat and sugar) of captive common marmoset milks fall within anthropoid norms, composition is highly variable among individual samples, with concentrations of milk fat ranging from below 1 to over 10%. To examine the extent to which this variation might be a consequence of captive conditions, we collected milk samples from wild common marmosets freely living on a farm in the state of Rio de Janeiro, Brazil. The proximate composition of the milk samples was assayed using identical techniques as used for the captive marmoset milks. The composition of the milk of wild common marmosets was also variable, but tended to be lower in dry matter, fat, protein and gross energy, and higher in sugar than milks from captive animals. Interestingly, the percentage of estimated gross energy from the protein fraction of the milks was relatively constant in both wild and captive marmosets and did not differ between wild and captive animals: lkcal of common marmoset milk contains on average (+ SEM) 0.035 + .001 g of protein regardless of the gross energy content of the milk or whether the milk was from a wild or captive animal. In contrast, in 1 kcal of low-energy milks, the amount of sugar was significantly higher and the amount of fat significantly lower than in 1 kcal of high-energy milks. Thus, common marmoset milk exhibits axes of variability (especially fat concentration) as well as a significant stability in the relative amount of protein. Am. J. Primatol. 70:78-83, 2008.
In 1960, the Golden lion tamarin Leontopithecus rosalia was almost extinct in the wild and the captive population, with poor reproduction and survival, was not well established. In the 1970s, after many improvements, the captive population began to grow and the Poço das Antas Biological Reserve was created to protect the species. In the 1980s, long‐term research was begun on the demography and socio‐ecology of the Golden lion tamarins, along with community environmental education and a reintroduction programme of captive‐born animals (initially in the reserve, later in neighbouring private forests). About 30 zoos contributed the 146 captive‐born reintroduced tamarins, and provided information on social behaviour, nutrition and health that was critical to developing reintroduction strategies. In 1994, threatened groups isolated in small fragments were rescued and translocated to a protected forest. Both programmes have been successful as measured by survival and reproduction after release, and both techniques have established growing populations. Although new threats (introduction of exotic primates) continue to challenge our efforts to preserve the species, there is no doubt of the success of almost 30 years of the Golden Lion Tamarin Conservation Programme.
Background Callithrix marmosets are a relatively young primate radiation, whose phylogeny is not yet fully resolved. These primates are naturally para- and allopatric, but three species with highly invasive potential have been introduced into the southeastern Brazilian Atlantic Forest by the pet trade. There, these species hybridize with each other and endangered, native congeners. We aimed here to reconstruct a robust Callithrix phylogeny and divergence time estimates, and identify the biogeographic origins of autochthonous and allochthonous Callithrix mitogenome lineages. We sequenced 49 mitogenomes from four species (C. aurita, C. geoffroyi, C. jacchus, C. penicillata) and anthropogenic hybrids (C. aurita x Callithrix sp., C. penicillata x C. jacchus, Callithrix sp. x Callithrix sp., C. penicillata x C. geoffroyi) via Sanger and whole genome sequencing. We combined these data with previously published Callithrix mitogenomes to analyze five Callithrix species in total. Results We report the complete sequence and organization of the C. aurita mitogenome. Phylogenetic analyses showed that C. aurita was the first to diverge within Callithrix 3.54 million years ago (Ma), while C. jacchus and C. penicillata lineages diverged most recently 0.5 Ma as sister clades. MtDNA clades of C. aurita, C. geoffroyi, and C. penicillata show intraspecific geographic structure, but C. penicillata clades appear polyphyletic. Hybrids, which were identified by phenotype, possessed mainly C. penicillata or C. jacchus mtDNA haplotypes. The biogeographic origins of mtDNA haplotypes from hybrid and allochthonous Callithrix were broadly distributed across natural Callithrix ranges. Our phylogenetic results also evidence introgression of C. jacchus mtDNA into C. aurita. Conclusion Our robust Callithrix mitogenome phylogeny shows C. aurita lineages as basal and C. jacchus lineages among the most recent within Callithrix. We provide the first evidence that parental mtDNA lineages of anthropogenic hybrid and allochthonous marmosets are broadly distributed inside and outside of the Atlantic Forest. We also show evidence of cryptic hybridization between allochthonous Callithrix and autochthonous C. aurita. Our results encouragingly show that further development of genomic resources will allow to more clearly elucidate Callithrix evolutionary relationships and understand the dynamics of Callithrix anthropogenic introductions into the Brazilian Atlantic Forest.
Animal hybridization is well documented, but evolutionary outcomes and conservation priorities often differ for natural and anthropogenic hybrids. Among primates, an order with many endangered species, the two contexts can be hard to disentangle from one another, which carries important conservation implications. Callithrix marmosets give us a unique glimpse of genetic hybridization effects under distinct natural and human-induced contexts. Here, we use a 44 autosomal microsatellite marker panel to examine genome-wide admixture levels and introgression at a natural C. jacchus and C. penicillata species border along the São Francisco River in NE Brazil and in an area of Rio de Janeiro state where humans introduced these species exotically. Additionally, we describe for the first time autosomal genetic diversity in wild C. penicillata and expand previous C. jacchus genetic data. We characterize admixture within the natural zone as bimodal where hybrid ancestry is biased toward one parental species or the other. We also show evidence that São Francisco River islands are gateways for bidirectional gene flow across the species border. In the anthropogenic zone, marmosets essentially form a hybrid swarm with intermediate levels of admixture, likely from the absence of strong physical barriers to interspecific breeding. Our data show that while hybridization can occur naturally, the presence of physical, even if leaky, barriers to hybridization is important for maintaining species genetic integrity. Thus, we suggest further study of hybridization under different contexts to set well informed conservation guidelines for hybrid populations that often fit somewhere between “natural” and “man-made.”
Marmosets (Callithrix spp.) have been introduced widely in areas within
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