Gonzalo Navarro

Plant and animal endemism in the eastern Andean slope: challenges to conservation

BackgroundThe Andes-Amazon basin of Peru and Bolivia is one of the most data-poor, biologically rich, and rapidly changing areas of the world. Conservation scientists agree that this area hosts extremely high endemism, perhaps the highest in the world, yet we know little about the geographic distributions of these species and ecosystems within country boundaries. To address this need, we have developed conservation data on endemic biodiversity (~800 species of birds, mammals, amphibians, and plants) and terrestrial ecological systems (~90; groups of vegetation communities resulting from the action of ecological processes, substrates, and/or environmental gradients) with which we conduct a fine scale conservation prioritization across the Amazon watershed of Peru and Bolivia. We modelled the geographic distributions of 435 endemic plants and all 347 endemic vertebrate species, from existing museum and herbaria specimens at a regional conservation practitioners scale (1:250,000-1:1,000,000), based on the best available tools and geographic data. We mapped ecological systems, endemic species concentrations, and irreplaceable areas with respect to national level protected areas.ResultsWe found that sizes of endemic species distributions ranged widely (< 20 km2 to > 200,000 km2) across the study area. Bird and mammal endemic species richness was greatest within a narrow 2500-3000 m elevation band along the length of the Andes Mountains. Endemic amphibian richness was highest at 1000-1500 m elevation and concentrated in the southern half of the study area. Geographical distribution of plant endemism was highly taxon-dependent. Irreplaceable areas, defined as locations with the highest number of species with narrow ranges, overlapped slightly with areas of high endemism, yet generally exhibited unique patterns across the study area by species group. We found that many endemic species and ecological systems are lacking national-level protection; a third of endemic species have distributions completely outside of national protected areas. Protected areas cover only 20% of areas of high endemism and 20% of irreplaceable areas. Almost 40% of the 91 ecological systems are in serious need of protection (= < 2% of their ranges protected).ConclusionsWe identify for the first time, areas of high endemic species concentrations and high irreplaceability that have only been roughly indicated in the past at the continental scale. We conclude that new complementary protected areas are needed to safeguard these endemics and ecosystems. An expansion in protected areas will be challenged by geographically isolated micro-endemics, varied endemic patterns among taxa, increasing deforestation, resource extraction, and changes in climate. Relying on pre-existing collections, publically accessible datasets and tools, this working framework is exportable to other regions plagued by incomplete conservation data.

Classification of the high-Andean Polylepis forests in Bolivia

This work investigates the Polylepis-dominated forests in the high Andes of central and southern Bolivia, using both the Braun-Blanquet approach and multivariate analysis. These are among the highest altitude forest types in the world, and the region under study is a center of diversity for the genus, and is located at the confluence of four biogeographical provinces. Nine main plant communities were distinguished. Correspondence Analysis revealed a strong dependence of community composition primarily on biogeographic as well as on bioclimatic features. The greatest forest type diversity is found in the central part of the Cordillera Oriental in the Tropical pluviseasonal bioclimate, within a Supratropical thermotype and a Subhumid ombrotype.

Aquatic Ranunculus communities in the northern hemisphere: A global review

Abstract This study offers a general review of aquatic ranunculi communities in the northern hemisphere, and includes aspects of their ecology, syntaxonomy and distribution. White-flowered ranunculi communities (Ranunculus subgenus Batrachium) grow in a wide range of habitats, including different types of water regime (still and flowing waters; permanent and seasonal waters) and nutrient states. They are mainly found in Eurasia. High richness is detected in Western Europe and the Mediterranean area of heterophyllous and laminar-leaved species, and in Asia of species with only dissected leaves. The western centre of the heterophyllous species has been related to waters with low mineralization and oscillation events occurring between the Mediterranean and Temperate climates. Yellow-flowered ranunculi communities (R. Xanthobatrachium) include heterophyllous species with a tendency to helophytism. They also are found in a wide range of aquatic habitats. There is an uneven degree of knowledge on the ecology of aquatic ranunculi communities, and further research is required into aquatic ranunculi habitats in Asia and North America.

Estudio fitosociológico de la vegetación de una zona de contacto Chaco-Cerrado en Santa Cruz (Bolivia)-

Fuentes, A. & Navarro, G. Phytosociological study of the vegetation in a Chaco-Cerrado contact area in Santa Cruz (Bolivia). Lazaroa 21: 73-109 (2001). The phytosociological study in an area of the eastern lowlands of Santa Cruz, Bolivia, describes the regional forest associations on the Chaco alluvial plain of the adjacent Brazilian Pre-Cambrian Shield as well as those of the aquatic vegetation belonging to the Brazilian-Paranean and Chaco biogeographic regions. Three forest associations are recognised in the Brazilian Shield: 1. Priogymnantho hasslerianae-Callisthenetum fasciculatae ass. nova (Cerrado woodland), 2. Machaerio scleroxyloni-Acosmietum cardenasii ass. nova («Chiquitano» dry forest) and 3. Viticio cymosae-Carinianetum ianeirensis ass. nova («Chiquitano» hygrophilous forest). There are four recognised forest associations on the Chaco plain: 1. Diplokelebo floribundae-Phyllostylonetum rhamnoidis ass. nova (transitional Chaco forest), 2. Diplokelebo floribundae-Trithrinacetum schizophyllae ass. nova (poorly drained Chaco thorn palm woodland), 3. Microlobio paraguensis-Copernicietum albae ass. nova (seasonally flooded palm woodland) and 4. Cratevo tapiae-Albizietum inundatae ass. nova (Chaco riparian woodland). There are also recognised associations of aquatic vegetation: 1. Lemno aequinoctialis-Wolfffielletum lingulatae (pleustophytic association), 2. Eichhornietum crassipedis (pleustohelophytic association), 3. Althernanthero aquaticae-Paspaletum elephantipes ass. nova (helophytic association) and 4. Mimoso chaetospherae-Ipomoeetum fistulosae ass. nova (helophytic nitrophilous dwarf-scrubland). The diagnoses, supported by their respective phytosociological tables, are presented here in unpublished, provisional and previously constructed syntaxonomic frameworks.

Towards an ecological classification of flooded savannas in Beni (Bolivia)

Abstract Two main types of flooded savannas are identified in Beni, one of the most extensive areas of flooded savannas in the Neotropics: the floodable savannas of the bajíos and the floodable savannas of the semi-uplands. Independent classification methods done for both floristic inventories and soil sampling show a strong relationship between the content and availability of exchangeable bases in the soils and floristic composition of the plant communities. The grassy savannas on mesotrophic substrates which are rich particularly in Mg and Ca are characterized floristically by Thevetia amazónica and Acroceras zizanioides. On base—poor substrates, the floodable grassy savannas, as well as the tajibo savanna, are best represented floristically by Andropogon bicornis and Coelorachis aurita. A CCA carried out on this type of savannas revealed a primary distribution pattern of the plant communities along an Fe gradient, which can also be explained as a gradient of the duration of the flooding period.