Biogeography of the Primates of Guyana: Effects of Habitat Use and Diet on Geographic Distribution

Species that exploit a wide range of resources or habitats (generalists) tend to be widely distributed, whereas species that exploit a narrow range of resources or habitats (specialists) often have a limited distribution. The distribution patterns are thought to result from specialists using relatively smaller habitats than those exploited by generalists. I used data from 1,725 km of primate surveys that I conducted in Guyana to test these hypotheses. Habitat breadth is the total number of different habitat types occupied by each species. I used the total number of different food categories exploited by each species to measure dietary breadth. Geographic range size is correlated with habitat breadth but not with dietary breadth or body size for the 8 primate species in Guyana. Habitat generalists—red howlers and wedge-capped capuchins—range into all habitats. Habitat specialists—spider monkeys, brown bearded sakis, and golden-handed tamarins—range only into large habitats. Habitat generalists tend to be dietary type specialists in Guyana. I suggest that only habitat generalists can subsist on the low-quality foods in small habitats in Guyana. Conversely, habitat specialists tend to be dietary type generalists in Guyana. They must feed on a variety of food types in large habitats. However, using the number of food categories exploited as a measure of dietary breadth may be only a weak aspect of multidimensional niche. Researchers testing biogeographic hypotheses associated with dietary breadth should consider including multivariate indicators of both the types of food categories eaten and the number of plant species exploited.     

Primate Community Structure in Guyana: A Biogeographic Analysis

Studies of primate community structure increase our understanding of behavior, adaptation, and evolution. However, there are few biogeographic data on specific composition and association patterns in primate communities. I conducted a biogeographic analysis of the community structure of primate species at 16 sites in Guyana. I used data from 1725 km of line-transect censuses to determine specific composition and association patterns of 220 primate groups . Of the 18 polyspecific groups, 94.1% (N = 16) included squirrel monkeys. There was an overall trend towards positive specific associations among Guyanese primates. The only species that exhibited a negative pattern of interspecific associations were brown and wedge-capped capuchins. The sighting rate for wedge-capped capuchins at sympatric sites was particularly depressed compared to that for brown capuchins. Low plant productivity in Guyanese forests may reduce the diversity of feeding niches and result in a low incidence of polyspecific associations and scramble competition between wedge-capped and brown capuchins.     

Factors determining mammal species richness on habitat islands and isolates: habitat diversity, disturbance, species interactions and guild assembly rules

• 1 For over three decades the equilibrium theory of island biogeography has galvanized studies in ecological biogeography. Studies of oceanic islands and of natural habitat islands share some similarities to continental studies, particularly in developed regions where habitat fragmentation results from many land uses. Increasingly, remnant habitat is in the form of isolates created by the clearing and destruction of natural areas. Future evolution of a theory to predict patterns of species abundance may well come from the application of island biogeography to habitat fragments or isolates.
• 2 In this paper we consider four factors other than area and isolation that influence the number and type of mammal species coexisting in one place: habitat diversity, habitat disturbance, species interactions and guild assembly rules. In all examples our data derive from mainland habitat, fragmented to differing degrees, with different levels of isolation.
• 3 Habitat diversity is seen to be a good predictor of species richness. Increased levels of disturbance produce a relatively greater decrease in species richness on smaller than on larger isolates. Species interactions in the recolonization of highly disturbed sites, such as regenerating mined sites, is analogous to island colonization. Species replacement sequences in secondary successions indicate not just how many, but which species are included. Lastly, the complement of species established on islands, or in insular habitats, may be governed by guild assembly rules. These contributions may assist in taking a renewed theory into the new millennium.

     

Large and least isolated fragments preserve habitat specialist spiders best in dry sandy grasslands in Hungary

The role of fragment size, isolation and habitat diversity in the conservation of spider assemblages living in fragmented landscape were studied in dry sandy grasslands (East Hungary, Nyírség). Spiders were collected using pitfall traps at eight dry grassland fragments from 2001 to 2009 from March to October fortnightly. We tested the rules of island biogeography, which suggest that the species richness increases with the size and decreases with the isolation of fragments. The habitat diversity is an important factor for species richness, since large areas usually have more habitats; therefore, the number of species may be higher in these areas. During the 9-year study period, altogether 10,544 individuals belonging to 106 species were collected. Contradicting the classical theory, we found a significant negative relationship between the total number of spider species and the grassland size, while the ratio of sandy grassland specialist spider species increased with fragment size. The relationship between the ratio of generalist species and the fragment size was not significant. The overall species richness and the isolation of studied grasslands did not show a significant relationship. The ratio of sandy grassland specialist species decreased, while the ratio of generalist species increased with the increasing of isolation. The habitat diversity did not show any effect on spider species richness. We concluded that to conserve the habitat specialist species it is recommended to preserve the large and least isolated grassland fragments, furthermore to increase the size of small fragments with the restoration of the adjacent croplands.     

Phylogeny and comparative biogeography of Pionopsitta parrots and Pteroglossus toucans

Studies of Neotropical birds, and their distributions and areas of endemism, in particular, have been central in the formulation of hypotheses proposed to explain the high species diversity in the Neotropics. We used mtDNA sequence data (ATPase 6 and 8, COI, and cyt b) to reconstruct the species-level phylogenies for two genera, Pionopsitta (Aves: Psittacidae) and Pteroglossus (Aves: Ramphastidae), compare our results with previous morphology-based phylogenetic analyses, and estimate the absolute timing of lineage and biogeographic divergences. Both the Pionopsitta and Pteroglossus phylogenies support a hypothesis of area relationships in which a divergence of the Serra do Mar (Atlantic Forest, Brazil) region of endemism is followed by the divergence of cis- and trans-Andean regions, then a split between the upper and lower Amazon basin, next the divergence of the Guyana area, and finally diversification of taxa in the upper Amazon basin's areas of endemism. Phylogenies of both genera support a hypothesis of area relationships that is similar to that proposed by Prum [XIX International Ornithological Congress (1988), 2562] for high-vagility species, but while they agree on the relative timing of area divergence (vicariance) events, they yield different absolute time estimates for those divergences when the typical avian mtDNA clock calibration is used. Taken at face value, the time estimates indicate that both genera began to diversify before the start of the Pleistocene, and that climatic and habitat shifts alone do not account for the diversification of these taxa.     

Review of plant biogeographic studies in Brazil

Molecular phylogenetic studies have become a major area of interest in plant systematics, and their impacts on historical biogeographic hypotheses are not to be disregarded. In Brazil, most historical biogeographic studies have relied on animal phylogenies, whereas plant biogeographic studies have largely lacked a phylogenetic component, having a limited utility for historical biogeography. That country, however, is of great importance for most biogeographic studies of lowland tropical South America, and it includes areas from a number of biogeographic regions of the continent. Important biogeographic reports have been published as part of phylogenetic studies, taxonomic monographs, and regional accounts for small areas or phytogeographic domains, but the available information is subsequently scattered and sometimes hard to find. In this paper we review some relevant angiosperm biogeographic studies in Brazil. Initially we briefly discuss the importance of other continents as source areas for the South American flora. Then we present a subdivision of Brazil into phytogeographic domains, and we cite studies that have explored the detection of biogeographic units （areas of endemism） and how they are historically related among those domains. Examples of plant taxa that could be used to test some biogeographic hypotheses are provided throughout, as well as taxa that exemplify several patterns of endemism and disjunction in the Brazilian angiosperm flora.     

Large‐scale distribution patterns of mangrove nematodes: A global meta‐analysis

Mangroves harbor diverse invertebrate communities, suggesting that macroecological distribution patterns of habitat‐forming foundation species drive the associated faunal distribution. Whether these are driven by mangrove biogeography is still ambiguous. For small‐bodied taxa, local factors and landscape metrics might be as important as macroecology. We performed a meta‐analysis to address the following questions: (1) can richness of mangrove trees explain macroecological patterns of nematode richness? and (2) do local landscape attributes have equal or higher importance than biogeography in structuring nematode richness? Mangrove areas of Caribbean‐Southwest Atlantic, Western Indian, Central Indo‐Pacific, and Southwest Pacific biogeographic regions. We used random‐effects meta‐analyses based on natural logarithm of the response ratio (lnRR) to assess the importance of macroecology (i.e., biogeographic regions, latitude, longitude), local factors (i.e., aboveground mangrove biomass and tree richness), and landscape metrics (forest area and shape) in structuring nematode richness from 34 mangroves sites around the world. Latitude, mangrove forest area, and forest shape index explained 19% of the heterogeneity across studies. Richness was higher at low latitudes, closer to the equator. At local scales, richness increased slightly with landscape complexity and decreased with forest shape index. Our results contrast with biogeographic diversity patterns of mangrove‐associated taxa. Global‐scale nematode diversity may have evolved independently of mangrove tree richness, and diversity of small‐bodied metazoans is probably more closely driven by latitude and associated climates, rather than local, landscape, or global biogeographic patterns.     

The Effects of Biogeography and Biotic Interactions on Lemur Community Assembly

Geographic patterns of biodiversity result from broad-scale biogeographic and present-day ecological processes. The aim of this study was to investigate the relative importance of biogeographic history and ecology driving patterns of diversity in modern primate communities in Madagascar. I collected data on endemic lemur species co-occurrence from range maps and survey literature for 100 communities in protected areas. I quantified and compared taxonomic, phylogenetic, and functional dimensions of intra- and intersite diversity. I tested environmental and geographic predictors of diversity and endemism. I calculated deforestation rates within protected areas between the years 2000 and 2014, and tested if diversity is related to forest cover and loss. I found the phylogenetic structure of lemur communities could be explained primarily by remotely sensed plant productivity, supporting the hypothesis that there was ecological differentiation among ecoregions, while functional-trait disparity was not strongly related to environment. Taxonomic and phylogenetic diversity also increased with increasing topographic heterogeneity. Beta diversity was explained by both differences in ecology among localities and potential river barriers. Approximately 3000 km² were deforested in protected areas since the year 2000, threatening the most diverse communities (up to 31%/park). The strong positive association of plant productivity and topographic heterogeneity with lemur diversity indicates that high productivity, rugged landscapes support greater diversity. Both ecology and river barriers influenced lemur community ecology and biogeography. These results underscore the need for focused conservation efforts to slow the loss of irreplaceable evolutionary and ecological diversity.     

Are habitat islands islands? Woodliving beetles (Coleoptera) in deciduous forest fragments in boreal forest

Modern forestry has changed the fire dynamics in the boreal forest and as a result the size and number of deciduous forest patches have been reduced as well as the number of deciduous trees within the coniferous forest This has exaggerated the insularity of deciduous forest patches within the boreal coniferous forest zone In this paper I examine whether the diversity of beetles living in dead stems of deciduous trees follows the relationship with patch area to be predicted from island biogeographic theory, and to what extent the species assemblages differ between large and small patches and single deciduous trees within managed coniferous forests Three larger patches of deciduous forest (>120 ha) arisen as successions after forest fires in the late 1880's are compared with 6 small (<20 ha) patches of similar origin No difference in diversity could be detected between large and small patches A statistically significant difference between assembly composition was detected using matrix regression between a matrix of observed assembly similarities and a hypothetical similarity matrix based on the type of area in which the plot was situated (large- small or matrix) Finally I examined the distribution of the 56 most common beetle species over the habitat types investigated Thirty four species did not show any Significant habitat preference, 12 were found more often in clear-cut areas than expected 5 were over-represented in small patches, and 4 in large areas My explanation to this apparent lack of insularity effects is the relative recent commencement of intensive forestry in these areas and the fact that the matrix is of rather high quality that is inhabitable for numerous beetle species Thus the patches may be viewed as incipient islands still exchanging biota with their surroundings     

Extensions of Island Biogeography Theory predict the scaling of functional trait composition with habitat area and isolation

The Theory of Island Biogeography (TIB) predicts how area and isolation influence species richness equilibrium on insular habitats. However, the TIB remains silent about functional trait composition and provides no information on the scaling of functional diversity with area, an observation that is now documented in many systems. To fill this gap, we develop a probabilistic approach to predict the distribution of a trait as a function of habitat area and isolation, extending the TIB beyond the traditional species–area relationship. We compare model predictions to the body‐size distribution of piscivorous and herbivorous fishes found on tropical reefs worldwide. We find that small and isolated reefs have a higher proportion of large‐sized species than large and connected reefs. We also find that knowledge of species body‐size and trophic position improves the predictions of fish occupancy on tropical reefs, supporting both the allometric and trophic theory of island biogeography. The integration of functional ecology to island biogeography is broadly applicable to any functional traits and provides a general probabilistic approach to study the scaling of trait distribution with habitat area and isolation.     

The influence of matrix and edges on species richness patterns of ground beetles (Coleoptera: Carabidae) in habitat islands

Aim The aim of this study was to analyse whether, and how, the inclusion of habitat specialists and edge‐preferring species modifies the species–area relationship predictions of the island biogeography theory for an insect group (ground beetles, Coloptera: Carabidae) living in natural fragments. Species–habitat island area relationships applied to terrestrial habitat islands can be distorted by the indiscriminate inclusion of all species occurring in the fragments. Matrices surrounding terrestrial habitat fragments can provide colonists that do not necessarily distinguish the fragment from the matrix and can survive and reproduce there. Edge‐preferring species can further distort the expected relationship, as smaller fragments have larger edge:core ratios. Location Nineteen forest fragments were studied in the Bereg Plain, Hungary, and SW Ukraine. This area contains natural forest patches, mainly of oak and hornbeam, and supports a mountain entomofauna. Methods Ground beetles (Carabidae) present in the 19 forest patches were categorized into generalists, forest specialists and edge‐preferring species. We analysed the relationship between species richness and fragment area using species richness in the different categories. Results The assemblages contained a high share of generalist species (species that occur also in the surrounding matrix). Forest patch size and the number of generalist species showed a marginally significant negative relationship, indicating that generalist species were more important in smaller patches. Forest specialist species richness was correlated positively with patch area. Edge‐preferring species were shown to influence the species–area relationship: the number of edge‐preferring species increased with the edge:area ratio. Main conclusions Both generalist and edge‐preferring species can considerably distort the species–area relationship. Island biogeography theory can be applied to habitat islands only if the habitat islands are defined correctly from the viewpoint of the target species.     

Spatial Biodiversity Patterns of Madagascar's Amphibians and Reptiles

Madagascar has become a model region for testing hypotheses of species diversification and biogeography, and many studies have focused on its diverse and highly endemic herpetofauna. Here we combine species distribution models of a near-complete set of species of reptiles and amphibians known from the island with body size data and a tabulation of herpetofaunal communities from field surveys, compiled up to 2008. Though taxonomic revisions and novel distributional records arose since compilation, we are confident that the data are appropriate for inferring and comparing biogeographic patterns among these groups of organisms. We observed species richness of both amphibians and reptiles was highest in the humid rainforest biome of eastern Madagascar, but reptiles also show areas of high richness in the dry and subarid western biomes. In several amphibian subclades, especially within the Mantellidae, species richness peaks in the central eastern geographic regions while in reptiles different subclades differ distinctly in their richness centers. A high proportion of clades and subclades of both amphibians and reptiles have a peak of local endemism in the topographically and bioclimatically diverse northern geographic regions. This northern area is roughly delimited by a diagonal spanning from 15.5°S on the east coast to ca. 15.0°S on the west coast. Amphibian diversity is highest at altitudes between 800–1200 m above sea-level whereas reptiles have their highest richness at low elevations, probably reflecting the comparatively large number of species specialized to the extended low-elevation areas in the dry and subarid biomes. We found that the range sizes of both amphibians and reptiles strongly correlated with body size, and differences between the two groups are explained by the larger body sizes of reptiles. However, snakes have larger range sizes than lizards which cannot be readily explained by their larger body sizes alone. Range filling, i.e., the amount of suitable habitat occupied by a species, is less expressed in amphibians than in reptiles, possibly reflecting their lower dispersal capacity. Taxonomic composition of communities assessed by field surveys is largely explained by bioclimatic regions, with communities from the dry and especially subarid biomes distinctly differing from humid and subhumid biomes.     

Insular biogeography of the montane butterfly faunas in the Great Basin: comparison with birds and mammals

Summary Butterfly species lists were assembled for 18 Great Basin mountain ranges for which distributional data on mammals and birds have been analysed previously by other workers. The ranges represent remnant islands of the boreal habitat that once was continuous across the Great Basin but is now restricted to higher elevations as a result of climatic change at the close of the Pleistocene. The effects of biogeographic factors (area, distance, elevation) and habitat diversity on butterfly species number were examined. The Great Basin boreal butterfly faunas were found to be depauperate overall relative that of the principal mainland source, the Rocky Mountains, and were found to have fewer species than predicted by the mainland species-area data. However, only a weak area effect, and no distance effect, was detected by bivariate and multivariate analysis. Furthermore, the habitat diversity score found to explain virtually all the variation in bird species number in the same ranges in previous studies is only marginally significantly correlated with butterflies. When the butterflies are subdivided according to their vagility, the relative differences in the species-area correlation and slope (z-value) between the vagility categories were consistent with those found previously for mammals and birds, and, as predicted by theory, less vagile taxa exhibit higher species-area correlations and z-values. Overall, differences in the insular biogeography of buttterflies and vertebrates seem to reflect fundamental ecological differences between the taxa.     

Titi monkey biogeography: Parallel Pleistocene spread by Plecturocebus and Cheracebus into a post‐Pebas Western Amazon

Titi monkeys, subfamily Callicebinae, are a diverse, species‐rich group of Neotropical primates with an extensive range across South America. Their distribution in space and time makes them an interesting primate model for addressing questions of Neotropical historical biogeography. Our aim was to reconstruct the biogeographic history of Callicebinae to better understand their diversification patterns and the history of their colonisation of South America since the late Miocene. We reconstructed a time‐calibrated phylogeny of 19 titi species under Bayesian inference using two mitochondrial and 11 nuclear loci. Species were assigned across eight Neotropical areas of endemism, and statistical biogeographic methods implemented in BioGeoBEARS were employed to estimate ancestral areas using 12 biogeographic models. Our results indicate that the most recent common ancestor to extant titi monkeys was widespread from the present‐day Andean foothills in the Colombian Amazon, through the wet and dry savannas of Bolivia and Brazil, to the southern Atlantic forest of eastern Brazil. Genus‐level divergences were characterised by vicariance of ancestral range in the late Miocene. Species‐level diversification in Cheracebus and the Plecturocebus moloch group occurred as they spread across the Amazon in the Pleistocene and were largely characterised by a sequential, long‐distance “island‐hopping” dispersal model of speciation from a narrow area of origin through jump dispersal across rivers. This study comprises the first large‐scale investigation of the evolutionary history of titi monkeys in the context of Amazonian and South American historical biogeography and sheds light on the processes that generated the great diversity found among Callicebinae.     

Subsidized Island Biogeography Hypothesis: another new twist on an old theory

We present a new hypothesis for predicting and describing patterns of species diversity on small islands and habitat fragments. We have modified the traditional island biogeography equilibrium theory to incorporate the influence of spatial subsidies from the surrounding matrix, which vary among islands and habitat fragments, on species diversities. The modification indicates three possible directions for the effects of spatial subsidies on diversity, which depend on where the focal community falls on the hypothesized unimodal curve of the productivity–diversity relationship. The idea is novel because no recent syntheses of productivity–diversity–area relationships examine the role of allochthonous resources on recipient communities’ diversity patterns.     

Phylogenetic community structure and phylogenetic turnover across space and edaphic gradients in western Amazonian tree communities

Ecological and evolutionary processes influence community assembly at both local and regional scales. Adding a phylogenetic dimension to studies of species turnover allows tests of the extent to which environmental gradients, geographic distance and the historical biogeography of lineages have influenced speciation and dispersal of species throughout a region. We compare measures of beta diversity, phylogenetic community structure and phylobetadiversity (phylogenetic distance among communities) in 34 plots of Amazonian trees across white‐sand and clay terra firme forests in a 60 000 square kilometer area in Loreto, Peru. Dominant taxa in white‐sand forests were phylogenetically clustered, consistent with environmental filtering of conserved traits. Phylobetadiversity measures found significant phylogenetic clustering between terra firme communities separated by geographic distances of <200–300 km, consistent within recent local speciation at the watershed scale in the Miocene‐aged clay‐soil forests near the foothills of the Andes. Although both distance and habitat type yielded statistically significant effects on both species and phylogenetic turnover, the patterns we observed were more consistent with an effect of habitat specialization than dispersal limitation. Our results suggest a role for both broad‐scale biogeographic and evolutionary processes, as well as habitat specialization, influencing community structure in Amazonian forests.     

Environmental Correlates for Species Richness among Amphibians and Reptiles in a Climate Transition Area

Correlations between environmental factors and the distribution of amphibian and reptile species richness were investigated in a climate transition area, Peneda-Gerês National Park (PNPG), in North-Western Portugal. Using presence-data at a local-scale (1 × 1 km), Ecological-Niche Factor Analysis (ENFA) identified a mixture of climatic (precipitation and number of days with fog), topographical (altitude and relief) and habitat factors (number of watercourses and water surfaces, the type of the largest water surface and tree diversity cover), as accurate predictors of species occurrence. Three factors were common for both taxonomic groups, and consistently presented a positive relation with species occurrence: precipitation, number of water surfaces, and tree diversity cover; suggesting a strong coincidence in the environmental correlates that influence amphibian and reptile species richness. Distribution patterns of observed and predicted species richness were compared using a Geographical Information System. Overall, three high species richness areas were predicted in common for both taxonomic groups and two additional areas for amphibians only. These areas matched with the observed species richness but suggested larger areas of high species richness. The location of the PNPG in a biogeographic crossroad, between Euro-Siberian and Mediterranean provinces, emphasised species richness of amphibians and reptiles and suggests a high priority conservation status for this protected area. Most of Central-Northern Portugal is located in a climatic transition area; therefore, increased species richness should be expected for other areas. Local scale studies for other protected areas should be planned as a framework for the development of multi-scale conservation planning by Portuguese authorities.     

Effects of Habitat Structure and Fragmentation on Diversity and Abundance of Primates in Tropical Deciduous Forests in Bolivia

Habitat structure and anthropogenic disturbance are known to affect primate diversity and abundance. However, researchers have focused on lowland rain forests, whereas endangered deciduous forests have been neglected. We aimed to investigate the relationships between primate diversity and abundance and habitat parameters in 10 deciduous forest fragments southeast of Santa Cruz, Bolivia. We obtained primate data via line-transect surveys and visual and acoustic observations. In addition, we assessed the vegetation structure (canopy height, understory density), size, isolation time, and surrounding forest area of the fragments. We interpreted our results in the context of the historical distribution data for primates in the area before fragmentation and interviews with local people. We detected 5 of the 8 historically observed primate species: Alouatta caraya, Aotus azarae boliviensis, Callithrix melanura, Callicebus donacophilus, and Cebus libidinosus juruanus. Total species number and detection rates decreased with understory density. Detection rates also negatively correlated with forest areas in the surroundings of a fragment, which may be due to variables not assessed, i.e., fragment shape, distance to nearest town. Observations for Alouatta and Aotus were too few to conduct further statistics. Cebus and Callicebus were present in 90% and 70% of the sites, respectively, and their density did not correlate with any of the habitat variables assessed, signaling high ecological plasticity and adaptability to anthropogenic impact in these species. Detections of Callithrix were higher in areas with low forest strata. Our study provides baseline data for future fragmentation studies in Neotropical dry deciduous forests and sets a base for specific conservation measures.