All Neotropical primates are arboreal and thus depend on forests for their survival. Arboreality puts many Neotropical primates at risk of extinction due to the high rates of deforestation in the ...tropics. We assessed the influence of vegetation structure and forest patch attributes on the occurrence of the threatened red-handed howler monkey (Alouatta belzebul) in an Amazonian savanna. Using a sample of 38 forest patches in a region of approximately 2000 km
in the state of Amapá, northern Brazil, we used logistic regression to find the best predictors of the occurrence of A. belzebul. We assessed patch area, patch isolation, the proportion of seasonally flooded forest in the patch, the density of flooded area palms, forest height, canopy cover, and diameter at breast height of trees. Patch area and palm density were the best predictors of the occurrence of A. belzebul in forest patches, both having a positive effect on the probability of occurrence. Our results indicate that areas of flooded forest in forest patches may be keystone habitats for A. belzebul living in Amazonian savannas. The observed effect of palm density on A. belzebul suggests that this variable is useful for planning conservation actions, including the selection of areas for protection and management strategies for areas inhabited by this primate.
We assessed the spatial extent at which the species-landscape relationship is strongest (i.e. the scale of effect—SE) on primate occurrence (
Alouatta belzebul
,
Saguinus midas
,
Saimiri sciureus
, ...and
Sapajus apella
and
Cebus olivaceus
, the last two considered together in the analysis) and species richness and evaluated which landscape, patch, and human variables influence primate distribution in a savanna ecosystem in Brazil. We used nested buffers to measure the landscape attributes, and used these data to assess the SE of the species-landscape relationships. We explored the relative contributions of landscape, patch, and human variables to species richness and occurrences by using Generalized Linear Mixed Models and logistic regression. We found that the SE did not differ between primates, but did between two regions with different matrix composition. At the landscape level, occurrence of all species was higher as the distance to the nearest block of continuous forest decreased, but was lower as the amount of water bodies and anthropogenic cover in the matrix increased. The occurrence of
S. apella
,
C. olivaceus
and
A. belzebul
was positively related to forest cover, and all species but
A. belzebul
had higher occurrence in taller forest. The occurrence of
S. apella
,
C. olivaceus
and
A. belzebul
decreased closer to the city, and
S. apella
and
C. olivaceus
presence increased with the number of residents. Richness was negatively related to the number of residents and anthropogenic cover, but positively to forest height. We concluded that conservation planning for primates should follow a “functional landscape” perspective, by maintaining higher forest cover and minimizing the anthropogenic alterations in the matrix.
Although overhunting is amongst the main threats to biodiversity, wild meat is culturally and nutritionally important for many communities. Conservation initiatives should therefore address the ...drivers of hunting, rather than its practice alone. Here we gathered information from structured interviews with 68 local households to assess the drivers of hunting in a highly threatened Amazonian savannah complex, the Cerrado of Amapá in Brazil. We used regression models to evaluate the influence of socio-economic parameters and spatial variables on hunting prevalence and frequency. The only identified driver of hunting prevalence was forest cover, whereas five variables had significant effects on hunting frequency. The positive effect of forest cover and the negative effect of hunter's age on hunting frequency suggest that logistical and physical feasibility are important drivers of hunting frequency. Furthermore, we suggest that the negative effect of distance to urban centres may be related to the profitability of hunting. We base this on the negative effect of river length in the vicinity of households and per capita monthly income on hunting frequency, which corroborates the tendency of hunting frequency to decrease when alternatives to wild meat are more readily available. We argue that to reduce unsustainable hunting it is necessary both to raise awareness amongst local communities and involve them in the creation of management plans that conserve biodiversity and meet economic and social needs.
Fragmentation threatens biodiversity and forest-dwelling animals can be especially vulnerable. Neotropical primates inhabit forests and play ecological roles in maintaining forest biodiversity. ...Currently, many primate communities are restricted to forest fragments. We (1) evaluated the influence of environmental, matrix, and site attributes on species richness and functional traits of primates in the Neotropics; and (2) evaluated the effect of the sub-region on the relationships between primates and environmental, matrix, and site attributes. We conducted literature searches to find published data on primate communities in forest fragments throughout the Neotropics. Each fragment was assigned to 1 of 11 sub-regions: Mesoamerica, Tumbes-Chocó-Magdalena, Caribbean, Orinoco, Amazon, Atlantic Forest, Cerrado, Chaco, Andes, Caatinga, and Pampa. Based on actual and expected species occurrences, we calculated the proportion of primate species retained in the fragments, the mass retained, and dietary items retained considering reproductive and vegetative plant parts and prey. We used linear mixed models to correlate primate variables with environmental, matrix, and site attributes. Fragment area was more important for primate retention than environmental, matrix, and site attributes, with primate retention being higher in larger fragments. Fragment size was positively correlated with all primate variables, except for retention of prey consumption, whose retention decreased as water bodies and density of buildings in the matrix increased. Fragments within protected areas retained larger species than unprotected fragments. The proportion of extant mass retained and vegetative plant parts in the diet were highest in Mesoamerica and lowest in the Atlantic Forest. Conservation planning of Neotropical primates should consider both the differences among sub-regions, forest restoration to increase fragment size, and the creation of new protected areas, even in fragmented landscapes.
There is a long history of exploitation of the South American river turtle Podocnemis expansa. Conservation efforts for this species started in the 1960s but best practices were not established, and ...population trends and the number of nesting females protected remained unknown. In 2014 we formed a working group to discuss conservation strategies and to compile population data across the species’ range. We analysed the spatial pattern of its abundance in relation to human and natural factors using multiple regression analyses. We found that > 85 conservation programmes are protecting 147,000 nesting females, primarily in Brazil. The top six sites harbour > 100,000 females and should be prioritized for conservation action. Abundance declines with latitude and we found no evidence of human pressure on current turtle abundance patterns. It is presently not possible to estimate the global population trend because the species is not monitored continuously across the Amazon basin. The number of females is increasing at some localities and decreasing at others. However, the current size of the protected population is well below the historical population size estimated from past levels of human consumption, which demonstrates the need for concerted global conservation action. The data and management recommendations compiled here provide the basis for a regional monitoring programme among South American countries.
There is increasing evidence that large-bodied primates play important roles as seed dispersers and
in the maintenance of tree diversity in forest ecosystems. In this study we compared forest ...regeneration at two
sites with differing primate abundances in the Ecuadorian Chocoan rainforest. We predicted: (1) significant differences
in primate abundance between the two sites; (2) higher understory tree species richness and density at
the site with greater primate abundance; (3) the site with lower primate abundance characterized by tree species
dispersed by non-primate biotic agents and/or abiotic factors. We compared two sites, Tesoro Escondido (TE)
a campesino cooperative, and the El Pambilar (EP) wildlife refuge that both maintain populations of mantled
howler monkey (Alouatta palliata), the brown-headed spider monkey (Ateles fusciceps fusciceps) and the capuchin
monkey (Cebus capucinus). We characterized canopy structure by point-quadrant sampling, determined
primate abundance and sampled seedlings/saplings in 1 m2 plots, classifying tree species based on three dispersal
syndromes: adapted for primate dispersal, dispersed by other biological agents, and abiotic dispersal. We compared
sites in terms of primate abundance (groups and individuals observed per day) and regeneration characteristics
(overall density, species richness, and dispersal syndrome). We carried out within site comparisons and
constructed understory tree species accumulation curves. Overall the forests were structurally similar - with significantly
higher densities of A. f. fusciceps at TE. Encounter rates for the other two primate species were similar
at both sites. Understory tree density and species richness was significantly higher in TE with no stabilization of
tree species accumulation curves. The species accumulation curve for understory trees at EP stabilized. Higher
densities and species richness of primate dispersed tree species were observed at TE, with non-primate biotically
dispersed tree species the dominant dispersal syndrome at both sites. Our observations are consistent with those
from other studies investigating the role of large-bodied frugivorous primates in forest regeneration, and point
to a general pattern: future lowland tropical forest tree diversity depends on maintaining robust populations of
large primate species in these systems. It is highly probable that the maintenance of high levels of tree diversity
in Chocoan rainforests is dependent on the conservation of its largest resident primate, the critically endangered
brown-headed spider monkey (A. f. fusciceps).
Las diferencias estructurales del bosque pueden ser el producto de variaciones ambientales a diferentes escalas, entre ellas los suelos. Para evaluar tal asociación, se usaron los datos de estructura ...del bosque y de suelos de una parcela de 6ha establecida en un bosque de tierra firme de la Amazonía colombiana. Las variables edáficas y estructurales se redujeron con un análisis de componentes principales (ACP) y un análisis de regresión múltiple verificó si existía asociación entre los componentes edáficos y estructurales del ACP. La regionalización de las variables de estudio se verificó con variogramas isotrópicos; además, se construyeron mapas de distribución espacial. El ACP de las variables estructurales identificó dos componentes: dosel y sotobosque, los cuales explicaron el 43.9 y 36.2% de la varianza total, respectivamente; para las variables edáficas los cuatro primeros componentes explicaron globalmente el 81.9% de la varianza total. Los análisis de regresión mostraron que tanto el dosel como el sotobosque se asocian con mayores contenidos de arena y baja fertilidad del suelo (p<0.05), pero explicaron una proporción baja de la variabilidad total (R²=4.9% para dosel y 16.5% para sotobosque). Las tres variables de la estructura del sotobosque, Al, limo y arena presentaron autocorrelación espacial.
Primates are globally recognized as an important component of biodiversity, however, more than half of primate species in the world are threatened and agriculture expansion is one of the main ...threats. Brazil has one of the largest networks of protected areas (PAs) in the world, but there are some conservation gaps, such as the Amazonian savannas. We aim to identify a network of priority areas to conserve a Brazilian Amazonian savanna highly threatened by agriculture expansion, by using seven primate species and four vegetation types as targets. We constructed species distribution models (SDMs) for the primates and used a Systematic Conservation Planning approach. We defined as a quantitative conservation target the proportion of the distribution of each primate species within the network according to traits related to their vulnerability to extinction. In addition, we set a target of including at least 30% of each savanna type within priority areas. We created a map of potential use of the land for agriculture and another of environmental risk, which were included as costs in the decision process, and together with the SDMs and vegetation types, identified the network of priority areas by using the software Marxan. We evaluated the feasibility of implementing conservation actions, such as establishing Conservation Units (e.g. reserves managed by the government), or implementing community-based conservation actions in each priority area. Additionally, we estimated the economic investment (US$/year) required to establish Conservation Units across the priority areas. Conservation targets for primates and vegetation types were met by protecting 3,240 km2 of the Savannas of Amapá. An investment of approximately US$958,122/year over five years is required to turn these priority areas into Conservation Units, however, we propose other strategies such as conservation on community lands and public policies. All these strategies would allow for protecting forest cover and the heterogeneous environments that are suitable for primates and other biodiversity components.
Forests structural differences could result of environmental variations at different scales. Because soils are an important component of plant's environment, it is possible that edaphic and ...structural variables are associated and that, in consequence, spatial autocorrelation occurs. This paper aims to answer two questions: (1) are structural and edaphic variables associated at local scale in a terra firme forest of Colombian Amazonia? and (2) are these variables regionalized at the scale of work? To answer these questions we analyzed the data of a 6ha plot established in a terra firme forest of the Amacayacu National Park. Structural variables included basal area and density of large trees (diameter > or = 10cm) (Gdos and Ndos), basal area and density of understory individuals (diameter < 10cm) (Gsot and Nsot) and number of species of large trees (sp). Edaphic variables included were pH, organic matter, P, Mg, Ca, K, Al, sand, silt and clay. Structural and edaphic variables were reduced through a principal component analysis (PCA); then, the association between edaphic and structural components from PCA was evaluated by multiple regressions. The existence of regionalization of these variables was studied through isotropic variograms, and autocorrelated variables were spatially mapped. PCA found two significant components for structure, corresponding to the structure of large trees (G, Gdos, Ndos and sp) and of small trees (N, Nsot and Gsot), which explained 43.9% and 36.2% of total variance, respectively. Four components were identified for edaphic variables, which globally explained 81.9% of total variance and basically represent drainage and soil fertility. Regression analyses were significant (p < 0.05) and showed that the structure of both large and small trees is associated with greater sand contents and low soil fertility, though they explained a low proportion of total variability (R2 was 4.9% and 16.5% for the structure of large trees and small tress, respectively). Variables with spatial autocorrelation were the structure of small trees, Al, silt, and sand. Among them, Nsot and sand content showed similar patterns of spatial distribution inside the plot.
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