Diversity Of Biomes Research Articles

Ecotones – where biomes meet

news and update ISSN 1948-6596 commentary Ecotones – where biomes meet The classification of biomes (or vegetation types) represents one of the most basic summaries of ecological units and provides part of the basis of biogeography. The first systematic continen- tal biome map was a map of Africa produced by Schantz in 1923 (Kuchler 1960). Since then, bi- ome mapping has continually developed to in- form biodiversity sciences. Initially such devel- opments were mainly in the form of expert mapping, where vegetation scientists with good knowledge of the area being mapped, and often drawing on actual plant community data, drew the boundaries of biomes (Kent 2012). More recently, ever more reliance has been put on remote-sensing data, where algo- rithms are used to interpret satellite imagery to classify biome distributions (and other land use types; Xie et al. 2008). With the concomitant development of other large-scale spatial datasets, such as of climate and soil, there has been an increased interest in the drivers of biome distribution, or elements of vegetation such as woody cover, at macroecological scales (e.g., Stephenson 1990, Greve et al. 2011, Campo-Bescos et al. 2013). Understanding what drives biome distribution is especially important in the face of global change, in response to which the distribution of biomes may be expected to shift. It has been suggested that if such shifts are to take place, the transition zones between vegetation types, i.e. the ecotones, would be most suitable for monitoring such changes (e.g., Berner et al. 2013; though see Kupfer and Cairns 1996). Eco- tones are often also areas of high richness as they may harbour species from different bi- omes (e.g., van Rensburg et al. 2009), and may be important areas of gene flow and hybridiza- tion (Kark and van Rensburg 2006). Against this background of the im- portance of ecotones, and a lack of attention historically afforded them (Kark and van Rens- burg 2006), it is exciting that the South African Journal of Botany will shortly be releasing a special issue dealing with “biome boundaries” in the South African context (Potts et al. 2015a). South Africa harbours a particularly high diversity of biomes (Mucina and Ruther- ford 2006), with some regions of high biome turnover across relatively small geographic dis- tances (Fig. 1). This, together with the rich his- tory for biome research in the country (Potts et al. 2015a), makes the region a natural labora- tory to understand ecotones and their drivers. The special issue presents work conduct- ed at a range of spatial scales (Potts et al. 2015a), ranging from transplant experiments across biome boundaries (Esler et al. 2015) to works conducted across all biomes in the coun- try. One of the country-scale studies examines the use and limitations of dynamic vegetation models in understanding the shifts of biome boundaries in response to climate change (Moncrieff et al. 2015), while another examines the extent to which ecotones can be also used to differentiate between alien plant composi- tion (Rouget et al. 2015). Other studies look at the role of soils in determining biome distribution (reviewed in Potts et al. 2015a). One of these used soil car- bon isotope analyses to ask whether soil type might drive biome boundaries in a grassland- forest mosaic (Gray and Bond 2015). By exam- ining the depth profile of carbon isotopes they concluded the opposite: that biome affects soil carbon. In the fire-prone grasslands, fires de- plete nutrients, while nutrient build-up hap- pens in forests, which are protected from fires. In this system, disturbances, rather than the abiotic environment, drive the position of eco- tones. A number of papers in the special issue look at changes in vegetation structure and boundaries through time using repeat aerial and ground-based photography (reviewed in Potts et al. 2015a). These studies, which could illustrate how shifts in biome boundaries occur (e.g., Masubelele et al. 2015), illustrate the im- frontiers of biogeography 7.3, 2015 — © 2015 the authors; journal compilation © 2015 The International Biogeography Society

Convergent evolution across theAustralian continent: ecotype diversification drives morphological convergence in two distantly related clades ofAustralian frogs

Animals from different clades but subject to similar environments often evolve similar body shapes and physiological adaptations due to convergent evolution, but this has been rarely tested at the transcontinental level and across entire classes of animal. Australia's biome diversity, isolation and aridification history provide excellent opportunities for comparative analyses on broad-scale macroevolutionary patterns. We collected morphological and environmental data on eighty-four (98%) Australian hylid frog species and categorized them into ecotypes. Using a phylogenetic framework, we tested the hypothesis that frogs from the same ecotype display similar body shape patterns: (i) across all the Australian hylids, and (ii) through comparison with a similar previous study on 127 (97%) Australian myobatrachid species. Body size and shape variation did not follow a strong phylogenetic pattern and was not tightly correlated with environment, but there was a stronger association between morphotype and ecotype. Both arboreal and aquatic frogs had long limbs, whereas limbs of fossorial species were shorter. Other terrestrial species were convergent on the more typical frog body shape. We quantified the strength of morphological convergence at two levels: (i) between fossorial myobatrachid and hylid frogs, and (ii) in each ecomorph within the hylids. We found strong convergence within ecotypes, especially in fossorial species. Ecotypes were also reflected in physiological adaptations: both arboreal and cocooned fossorial frogs tend to have higher rates of evaporative water loss. Our results illustrate how adaptation to different ecological niches plays a crucial role in morphological evolution, boosting phenotypic diversity within a clade. Despite phylogenetic conservatism, morphological adaptation to repeatedly emerging new environments can erase the signature of ancestral morphotypes, resulting in phenotypic diversification and convergence both within and between diverse clades.

English

The purpose of this review was to study the presence of Mycobacterium leprae in the environment and its relation with meteorological variables such as temperature and humidity. There are reports, which provide evidence that meteorological factors such as temperature and soil humidity can influence the dynamics of M. leprae. However, leprosy cases are registered both in the rainy and dry seasons, indicating that M. leprae remains viable in different environmental conditions. Therefore, it is difficult to establish the meteorological pattern(s) required to maintain the bacilli in the environment. The extensive area of endemic countries, endemicity in the bordering countries, diversity of biomes, and lack of urban infrastructure together with weather features are possible factors that influence transmission of the disease. Key words: Leprosy, environmental health, molecular biology.

A full greenhouse gases budget of Africa: synthesis, uncertainties, and vulnerabilities

Abstract. This paper, developed under the framework of the RECCAP initiative, aims at providing improved estimates of the carbon and GHG (CO2, CH4 and N2O) balance of continental Africa. The various components and processes of the African carbon and GHG budget are considered, existing data reviewed, and new data from different methodologies (inventories, ecosystem flux measurements, models, and atmospheric inversions) presented. Uncertainties are quantified and current gaps and weaknesses in knowledge and monitoring systems described in order to guide future requirements. The majority of results agree that Africa is a small sink of carbon on an annual scale, with an average value of −0.61 ± 0.58 Pg C yr−1. Nevertheless, the emissions of CH4 and N2O may turn Africa into a net source of radiative forcing in CO2 equivalent terms. At sub-regional level, there is significant spatial variability in both sources and sinks, due to the diversity of biomes represented and differences in the degree of anthropic impacts. Southern Africa is the main source region; while central Africa, with its evergreen tropical forests, is the main sink. Emissions from land-use change in Africa are significant (around 0.32 ± 0.05 Pg C yr−1), even higher than the fossil fuel emissions: this is a unique feature among all the continents. There could be significant carbon losses from forest land even without deforestation, resulting from the impact of selective logging. Fires play a significant role in the African carbon cycle, with 1.03 ± 0.22 Pg C yr−1 of carbon emissions, and 90% originating in savannas and dry woodlands. A large portion of the wild fire emissions are compensated by CO2 uptake during the growing season, but an uncertain fraction of the emission from wood harvested for domestic use is not. Most of these fluxes have large interannual variability, on the order of ±0.5 Pg C yr−1 in standard deviation, accounting for around 25% of the year-to-year variation in the global carbon budget. Despite the high uncertainty, the estimates provided in this paper show the important role that Africa plays in the global carbon cycle, both in terms of absolute contribution, and as a key source of interannual variability.

A ROADMAP FOR RIPARIAN INVASION RESEARCH

ABSTRACTRiparian habitats provide numerous ecosystem services and support a diversity of ecological processes, yet they are environmentally sensitive landscapes susceptible to species invasion. As the global population grows, urban, exurban, suburban and rural development of riparian landscapes and dependence on the associated ecosystem services will increase. To preserve riparian systems, research should assess causes and consequences of riparian invasion and effective restoration measures across a diversity of biomes. This paper categorizes the types of riparian invasion research studies and investigates research trends in the riparian invasion literature. The analysis shows that research focuses on drivers and patterns of invasion is primarily focused on North America and Europe and is scant in high biodiversity biomes, such as the tropics and humid subtropics. Future population growth is predicted to occur in poorly researched regions. Future riparian invasion research should focus on regions of high biodiversity and identify consequences of invasion and restoration measures. Copyright © 2013 John Wiley & Sons, Ltd.

Five New Records of Drosophilids (Diptera) in a Riparian Forest in the Brazilian Savanna, an Endangered Neotropical Biome

AbstractAlthough drosophilids are widespread models in genetics and molecular biology, their diversity and distribution is relatively poorly known. Field information is important because it provides an appropriate framework to interpret genetic and evolutionary studies. We sampled drosophilids in the Brazilian savanna, one of 34 biodiversity hot spots worldwide. This extremely rich and endangered biome is highly seasonal and consists of a vegetation mosaic, ranging from open fields to riparian forests; these forests occupy only 5% of the Brazilian savanna but concentrate most of the biome's diversity. Twelve monthly collections in a riparian forest of the Brazilian savanna revealed 61 drosophilid species, comprising the genera Amiota Loew, Drosophila Fallén, Neotanygastrella Duda, Rhinoleucophenga Hendel, Scaptodrosophila Duda, Zaprionus Coquillett, and Zygothrica Wiedemann. This richness represents about a half of the recorded drosophilid species of the whole biome, and includes five new occurrences for the Brazilian savanna: the genus Amiota, Drosophila coffeata Williston, D. neorepleta Patterson and Wheeler, D. pseudosaltans Magalhães, and Rhinoleucophenga brasiliensis (Lima). This result suggests that drosophilid richness in this biome is likely to be high but remains understudied.

Land-sea interface features of four estuaries on the South America Atlantic coast

The Brazilian coastal zone extends from 4º N to 34º S latitude and because of its long extension, the interface zone from continent to ocean includes a high diversity of geomorphologic and oceanographic characteristics. The rivers from the Northeast and East regions are marked by a typical unimodal seasonal flux patterns but with different amplitudes. As the climate indicates, the rivers from the Northeast are subject to an accentuated seasonal variability with an elevated input and flood pulses during the rainy season and low to negligible fluxes during the dry season. Small-scale rivers usually present typical torrential behaviour. In the humid eastern region, the unimodal seasonal cycle is dampened with a more constant input supply. Recently, some studies have shown that the material supply from rivers along the Northeast and Eastern coasts is diluted by surface tropical waters of oceanic currents and that the estuarine plume dispersal is restricted to a narrow coastal belt. However, human impacts of course mask or even override both natural hydrological cycles and CO2 emissions from terrestrial biomes, or depending on the nature of the human impact, can even increase extreme events. Henceforth this contribution addresses the typological, hydrological and biome diversity of the four estuarine systems fed and affected by the respective Amazon, São Francisco, Paraíba do Sul and Plata watersheds.

How to set up a vivarium: maintaining the health and welfare of reptiles

The class Reptilia consists of over 7780 species distributed throughout the world, with warmer regions being home to more species than cooler regions. However certain species of reptile, the common adder and European lizard for example, can be found as far north as the Arctic Circle. Given this incredible diversity of biomes, it is impractical to do justice to the husbandry needs of this class of animal in one article. The focus of this article, therefore, will be on the key concepts of setting up a standard vivarium in order to maintain the health and welfare of its occupants.

Lichens of Aisen, Southern Chile

The lichen mycobiota of Aisen (southern Chile) comprises 319 taxa in 87 genera. All of the species of Menegazzia and Protousnea, previously recorded in Chile, are present in this region. The diversity of biomes, from temperate rainforests −particularly in oceanic zones− to steppe areas, offers an enormous number of macro and microhabitats favorable for lichens. The highest lichen diversity, 56 %, was recorded in an undisturbed locality in Laguna San Rafael National Park. Lichen species diversity is higher in oceanic temperate rainforests than in steppe areas, where the majority of Antarctic lichens (23 %) are registered. Levels of endemism are rather high (26 %) and are due mainly to species of the genera Protousnea, Pseudocyphellaria, Menegazzia, Cladonia, Sticta, Nephroma. Other biogeographical elements in the region’s lichen mycobiota are: cosmopolitan (16 %), austral (16 %) and bipolar (13 %). Lichen diversity in Aisen represents about 20 % of the known lichen mycobiota of Chile.

Plant Diversity Hotspots in the Atlantic Coastal Forests of Brazil

Plant-diversity hotspots on a global scale are well established, but smaller local hotspots within these must be identified for effective conservation of plants at the global and local scales. We used the distributions of endemic and endemic-threatened species of Myrtaceae to indicate areas of plant diversity and conservation importance within the Atlantic coastal forests (Mata Atlântica) of Brazil. We applied 3 simple, inexpensive geographic information system (GIS) techniques to a herbarium specimen database: predictive species-distribution modeling (Maxent); complementarity analysis (DIVA-GIS); and mapping of herbarium specimen collection locations. We also considered collecting intensity, which is an inherent limitation of use of natural history records for biodiversity studies. Two separate areas of endemism were evident: the Serra do Mar mountain range from Paraná to Rio de Janeiro and the coastal forests of northern Espírito Santo and southern Bahia. We identified 12 areas of approximately 35 km(2) each as priority areas for conservation. These areas had the highest species richness and were highly threatened by urban and agricultural expansion. Observed species occurrences, species occurrences predicted from the model, and results of our complementarity analysis were congruent in identifying those areas with the most endemic species. These areas were then prioritized for conservation importance by comparing ecological data for each.

Rapoport effect and biomic specialization in African mammals: revisiting the climatic variability hypothesis

AbstractAim One of the mechanisms proposed to explain the tendency for geographical range size to increase from the equator to the poles, known as the Rapoport effect, is the climatic variability hypothesis. It states that, towards higher latitudes, greater seasonal climatic variability is the most important pressure that selectively promotes greater general climatic tolerance of species, and therefore also more extensive species ranges. In order to test this hypothesis, we explore the influence of climate, area and biome diversity on the latitudinal gradient of climatic specialization.Location The study used the large mammal assemblage from Africa.Methods The degree of climatic specialization of African large mammals (Primates, Carnivora, Proboscidea, Perissodactyla, Hyracoidea, Tubulidentata, Artiodactyla and Pholidota) is investigated using the biomic specialization index (BSI) for each mammal species, based on the number of biomes it inhabits. We studied the influence of 11 climatic and biogeographical predictors in the latitudinal pattern of biomic specialization. Stepwise multiple regressions were used to identify the strongest predictors of biomic specialization in Africa and, separately, in both continental hemispheres. We also studied differences among taxonomical groups (primates, carnivores and artiodactyls). We used correlograms generated using Moran's I coefficients to control for spatial autocorrelation in all these analyses.Results Average BSI values for successive 1°‐latitude bands generally decline towards the equator and temperature variability emerged as the most predictive factor in the regression model for the whole continent, thus supporting the climatic variability hypothesis. Nevertheless, there are differences between hemispheres and among taxa. While temperature variability is the most important predictor of latitudinal variability in biomic specialization in most of the regression models for the northern hemisphere, continental area for each latitudinal band is the best predictor in all the regression models in the southern hemisphere.Main conclusions It appears that similar patterns in latitudinal variation in average BSI may be caused by different factors in the two hemispheres. We suggest that the strong north–south geographical asymmetry of Africa, which influences its biogeographical structure, and the presence of land connections with Eurasia in the northern hemisphere are responsible for the observed patterns. Our data illustrate the influence of continental biogeographical structure and history on macroecological patterns.

The biology of impact craters--a review.

Impact craters contain ecosystems that are often very different from the ecosystems that surround them. On Earth over 150 impact craters have been identified in a wide diversity of biomes. All natural events that can cause localized disruption of ecosystems have quite distinct patterns of rccovery. Impact events are unique in that they are the only extraterrestrial mechanism capable of disrupting an ecosystem locally in space and time. Thus, elucidating the chronological sequence of change at the sites of impacts is of ecological interest. In this synthetic review we use the existing literature, coupled with our own observations at the Haughton impact structure, Devon Island, Nunavut, Canada to consider the patterns of biological recovery at the site of impact craters and the ecological characteristics of impact craters. Three phases of recovery are suggested. The Phase of Thermal Biology, a phase associated with the localized, ephemeral thermal anomaly generated by an impact event. The Phase of Impact Succession and Climax, a phase marked by multiple primary and secondary succession events both in the aquatic realm (impact crater-lakes) and terrestrial realm (colonization of paleolacustrine deposits and impact-generated substrata) that are followed by periods of climax ecology. In the case of large-scale impact events (> 10(4) Mt), this latter phase may also be influenced by successional changes in the global environment. Finally, during the Phase of Ecological Assimilation, the disappearance of the surface geological expression of an impact structure results in a concomitant loss of ecological distinctiveness. In extreme cases, the impact structure is buried. Impact succession displays similarities and differences to succession following other agents of ecological disturbance, particularly volcanism.

Monitoring global change with phenology: The case of the spring green wave

The centuries-old practice of recording plant and animal events that take place at specific times each year (phenology) should play an important role in monitoring mid-latitude global changes. At least three problems related to the detection of biosphere changes could be investigated using this information. Firstly, the technique can be generalized from the local to global scale. Secondly, an integrated approach could be developed to represent biome diversity effectively. Lastly, physical mechanisms responsible for the events can be deduced in order to incorporate the phenological information into global-scale models, and detect changes in related environmental factors. With these goals in mind, regional phenological data collection networks were initiated in eastern North America during the early 1960s, using cloned lilacs and several species of honeysuckle. This paper reviews research projects which address the problems outlined above, using first leaf data (associated with spring green-up or “green wave” in mid-latitudes) gathered from these networks. The results of such studies in North America have demonstrated the potential of phenology as an efficient monitor of global change throughout mid-latitude regions. Future research efforts will concentrate on the development of a coordinated strategy to link phenological information from satellites, indicator plants (such as the lilac), and representative species from each biome.