Gap analysis of two savanna-type ecoregions: a two-scale floristic approach applied to the Llanos de Moxos and Beni Cerrado,Bolivia

The Beni savannas (locally referred to as pampas) is composed of two clearly differentiated ecoregions, the Llanos de Moxos (or Moxos) and the Beni Cerrado. Both tropical savannas are shaped to a greater (Moxos) or lesser (Beni Cerrado) by cycles of drought and flood and the labor of generation of farmers. It contains floristic elements of four biogeographic regions (Amazonian, Chaco, Cerrado and Chiquitana). However, in spite of their biological richness, they are little represented in the National System of Protected Areas (SNAP, in Spanish). By employing an ecoregion and sub-ecoregion approach, we examined the representation of both savanna-type ecoregions in the Departmental System of Protected Areas (SDAP, in Spanish), which includes national, departmental, municipal, and private protected areas. The study also enabled us to compare Bolivia’s newest ecoregion/vegetation zones maps as applied to the both savannas and to produce a sub-ecoregion map for the Beni department (northeastern Bolivia). Our results show that the Llanos de Moxos and the Beni Cerrado are found in protected areas of departmental and municipal level. Although they are still under-represented (mainly the Beni Cerrado), they have nonetheless important extensions inside these protected areas. A better representation of these zones would guarantee improved levels of protection of these unique ecosystems. On the other hand, our study shows the importance of the conservation-representation target relationships (sensu Rodrigues et al. 2004). This is the first time that this approach is used to examine gaps of floristic representativeness of savanna-type ecoregions showing that the traditional 10% minimal conservation target should be used with caution.     

Relationship between floral traits and floral visitors in two coexisting Tecoma species (Bignoniaceae)

In this paper, we studied the floral biology of Tecoma fulva ssp. garrocha and T.?stans in Vaqueros (Salta, Argentina), where both species coexist. We tested the idea that floral traits are associated with the pollinator types that visit them. According to our results, T.?fulva ssp. garrocha presented traits common to bird flowers and were visited by two species of Trochilidae (Colibri serrirostris and Chlorostilbon lucidus). In addition, T.?stans exhibited traits common to hymenoptera flowers and were visited principally by Apis mellifera and Bombus atratus. This study showed that floral traits are predictive of animal visitors.     

America's Most Famous Human Footprints: History,Context and First Description of Mid-Holocene Tracks from the Shores of Lake Managua,Nicaragua

Human tracks discovered in 1874 at a site named El Cauce or Acahualinca near the shores of Lake Managua, Nicaragua, are the most famous and abundant human tracks in the Americas. They represent a landmark ichnological discovery during the late 19th century that generated much debate regarding their age and origins. Reported dates for the tracks range from 2,120 to 6,500 B.P. The site, which is now situated within the limits of Nicaragua's capital city of Managua, forms the basis of the Acahualinca Tracks Museum (Huellas de Acahualinca) and has been in place since 1953. However, it is still little known and has not been systematically studied, despite being an important window into Meso-American prehistory. Two exposures of a surface of volcanic ash reveal hundreds of human tracks comprising a minimum of 12 clearly defined trackways, and a trampled zone or path representing at least three more individuals, all heading in the same northwesterly direction. Tracks of deer, opossum and at least one bird are also present. Bison tracks collected from another nearby site (El Recreo) that is no longer accessible are on display at the museum. The Acahualinca tracks are noteworthy for the exceptional quality of preservation. We herein present the first maps of the two exposures, which combine to tell a story of human and animal activity along the shores of ancient Lake Managua several thousand years ago.     

Building multiple nests is associated with reduced breeding performance in a south temperate population of Grass Wrens Cistothorus platensis platensis

Grass Wrens Cistothorus platensis build two types of non-breeding nest structures: platforms and dummy nests. Platforms are rudimentary accumulations of grasses concealed between vegetation. Dummy and breeding nests are dome-shaped with a similar structural layer. We used a nest-removal experiment and observational data to evaluate several hypotheses regarding the adaptive significance of building multiple nests in a south temperate population of Grass Wrens. Building non-breeding nests was not a strategy of males to attract additional females, as most of these nests were built after pair formation and both sexes collaborated during building. Building non-breeding nests was not a post-pairing display as the presence of multiple nests did not increase female investment in the breeding attempt: clutch size and female provisioning to nestlings did not differ between experimental and control territories where no non-breeding nests were removed. Similarly, in non-manipulated territories, clutch size and female provisioning were not correlated with the number of non-breeding nests or with males’ nest-building effort. Contrary to this hypothesis, the number of non-breeding nests was associated with delayed clutch initiation and reduced hatching success. The presence of non-breeding nests did not reduce nest predation and brood parasitism, which did not differ between experimental and control territories. We did not detect differences in concealment between non-breeding and breeding nests, suggesting that non-breeding nests were not the result of abandonment before egg-laying to reduce subsequent nest predation. Dummy nests did not provide shelter; they were not used frequently for roosting over the breeding season and were not maintained during the non-breeding season. We suggest that building non-breeding nests may be an attempt by males to manipulate the decision of females to breed with a mate they might otherwise reject or to start reproduction earlier than optimal for the females.