Plant Management in the Tehuacán-Cuicatlán Valley, Mexico1

Plant Management in the Tehuacán-Cuicatlán Valley, Mexico. Plant management types currently practiced in the Tehuacán-Cuicatlán Valley, México, were documented and analyzed based on ethnobotanical studies conducted in 13 villages with six indigenous groups and Mestizo people. The information was organized in a data base, and then detailed and guided to a consensus through six workshops carried out by ethnobotanists working in the area. From a total of 1,608 useful plant species, we identified 610 with at least one management type other than simple gathering. Managed species are mainly used as food, fodder, medicinal, and ornamental, and they belong to 101 plant families. The higher species numbers were recorded in Cactaceae, Asteraceae, Fabaceae, Crassulaceae, and Agavaceae. Nearly 60% of the managed species are native to the region and the rest are introduced from other regions of Mexico and the world. In total, 400 species are ex situ managed out of their natural environments through seed sowing and/or planting their vegetative propagules or entire young plants; 373 species are in situ managed in their natural habitats as follows: all these species are deliberately left standing during vegetation clearance, 76 species are also enhanced intentionally favoring their abundance through modifications of their habitat, or directly by planting their propagules, and 51 receive protection through regulations, particular strategies of extraction, and actions against herbivores, competitors, freezing, radiation, and drought. Most management forms involve artificial selection at different intensity levels. The information allows visualizing co-occurrence of incipient and advanced forms of management at different intensity levels within and among species, which helps to postulate testable hypotheses on factors influencing plant management and domestication in an important area for studying the origins of agriculture.     

Healing in the Sámi North

There is a special emphasis today on integrating traditional healing within health services. However, most areas in which there is a system of traditional healing have undergone colonization and a number of pressures suppressing tradition for hundreds of years. The question arises as to how one can understand today’s tradition in light of earlier traditions. This article is based on material collected in Sámi areas of Finnmark and Nord-Troms Norway; it compares local healing traditions with what is known of earlier shamanic traditions in the area. The study is based on 27 interviews among healers and their patients. The findings suggest that although local healing traditions among the Sámi in northern Norway have undergone major transformations during the last several hundred years, they may be considered an extension of a long-standing tradition with deep roots in the region. Of special interest are also the new forms tradition may take in today’s changing global society.     

Darwin's Galápagos finches in modern biology

One of the classic examples of adaptive radiation under natural selection is the evolution of 15 closely related species of Darwin''s finches (Passeriformes), whose primary diversity lies in the size and shape of their beaks. Since Charles Darwin and other members of the Beagle expedition collected these birds on the Galápagos Islands in 1835 and introduced them to science, they have been the subjects of intense research. Many biology textbooks use Darwin''s finches to illustrate a variety of topics of evolutionary theory, such as speciation, natural selection and niche partitioning. Today, as this Theme Issue illustrates, Darwin''s finches continue to be a very valuable source of biological discovery. Certain advantages of studying this group allow further breakthroughs in our understanding of changes in recent island biodiversity, mechanisms of speciation and hybridization, evolution of cognitive behaviours, principles of beak/jaw biomechanics as well as the underlying developmental genetic mechanisms in generating morphological diversity. Our objective was to bring together some of the key workers in the field of ecology and evolutionary biology who study Darwin''s finches or whose studies were inspired by research on Darwin''s finches. Insights provided by papers collected in this Theme Issue will be of interest to a wide audience.     

Molecular dissection of the role of histidine in nickel hyperaccumulation in Thlaspi goesingense (Hálácsy)

To understand the role of free histidine (His) in Ni hyperaccumulation in Thlaspi goesingense, we investigated the regulation of His biosynthesis at both the molecular and biochemical levels. Three T. goesingense cDNAs encoding the following His biosynthetic enzymes, ATP phosphoribosyltransferase (THG1, GenBank accession no. AF003347), imidazoleglycerol phosphate dehydratase (THB1, GenBank accession no. AF023140), and histidinol dehydrogenase (THD1, GenBank accession no. AF023141) were isolated by functional complementation of Escherichia coli His auxotrophs. Northern analysis of THG1, THD1, and THB1 gene expression revealed that each gene is expressed in both roots and shoots, but at the concentrations and dosage times of Ni treatment used in this study, these genes failed to show any regulation by Ni. We were also unable to observe any increases in the concentration of free His in root, shoot, or xylem sap of T. goesingense in response to Ni exposure. X-ray absorption spectroscopy of root and shoot tissue from T. goesingense and the non-accumulator species Thlaspi arvense revealed no major differences in the coordination of Ni by His in these tissues. We therefore conclude that the Ni hyperaccumulation phenotype in T. goesingense is not determined by the overproduction of His in response to Ni.     

Cofán Indians’ Monitoring of Freshwater Turtles in Zábalo,Ecuador

The Cofán Indians of Aguarico and Zábalo Rivers in Ecuador in 1990 began a turtle recuperation effort by raising turtle hatchlings (Podocnemis expansa and P. unifilis) in small pools. To evaluate the effectiveness of this program, the Cofán developed and tested three methods to document changes in the populations of turtles. The first method consisted of interviews with people from neighbouring communities about their perceptions of changes in turtle abundance. The second method was a direct count of turtles observed along the rivers from canoe. The third method was an indirect count, involving turtle nest censusing along community beaches. Two of the methods yielded numerical, statistically positive turtle population trends. The turtle program has influenced the community's perception of turtle conservation issues so that, instead of hunting the adults and eggs, they now protect them. The training in record-keeping permits them to make a transparent history of the equitability of access to the turtle egg resource. The Cofán monitoring experience strengthened their successful petition to the Ecuadorian government for the rights to manage their territorial lands within the Cuyabeno Wildlife Reserve, and to receive protected area status and management rights to other ancestral lands. The experience gained by the Zábalo monitors is now serving as a model for the design and implementation of the park monitoring system of the newly-established Cofán Park Ranger Corps, which will be patrolling three Ecuadorian Ecological Reserves which overlap Cofán inhabited areas.     

Plant functional diversity in tropical Andean páramos

ABSTRACT

Background: Tropical high mountains present extreme daily temperature variations, frequent high air evaporative demands and seasonal differences in soil water availability. Plants have adapted to these conditions through different avoidance-tolerance mechanisms. This review focuses on plant-growth forms and their adaptive strategies.

Aims: This integrated review of páramo plant traits aims at contributing to understanding the functioning of plant-growth forms and their significance on ecosystem properties under environmental climate and land-use changes.

Methods: Plant responses are presented along avoidance-tolerance gradients considering three main aspects: freezing resistance, water relations and gas exchange characteristics. Results from 45 herbaceous and 42 woody species along elevational gradients in the Venezuelan high Andes were analysed.

Results: Leaf supercooling is the common avoidance response of woody plants to night-time freezing temperatures, while herbaceous plants tolerate frost. Trees and caulescent rosettes maintain more positive leaf water potentials under water deficit conditions compared to more tolerant herbaceous species. All plant growth-forms showed strong stomatal control under dry-season conditions.

Conclusions: Páramo plant growth-forms may be separated according to an avoidance-tolerance gradient in response to water deficit and low temperature resistance. Woody growth-forms tend to avoid both freezing and water stress, while herbaceous forms tolerate frost and resist an unfavourable water status. Grasses and cushion plants are at the tolerant extreme of the gradient and coincide in that both reach the highest elevations in the páramo. Andean giant rosettes are freezing avoidant, particularly susceptible to water deficit and the most vulnerable, of all growth-forms, to changing environmental conditions.     

Mercury contamination in Lake Xolotlán (Managua)

Total mercury was measured in different compartments of Lake Xolotlán's (Managua) ecosystemviz., sediments, water, fish and men. Sediments from 18 localities at 5 depths inside the sediment (5, 10, 15, 20 and 25 cm) contained an average concentration of 0.62 g Hg.g^–1±0.46 at the surface, with extreme values of 0.16 and 1.8 g.g^–1. The highest concentration was observed at 25 cm depth in front of the chlor-alkaly factory (ELPESA). This maximum is associated with the period of highest production of this factory. The highest mercury concentrations in water were also measured close to the discharge of ELPESA,viz. 787 g.Hg^–1 in January and 506 g.g^–1 in April. The mean mercury concentrations measured in the muscles of the most consumed fish were 0.63 g.g^–1±0.22 (extreme values 0.22 and 1.45) inCichlasoma managuense, and 0.07 g.g^–1±0.14 (extreme values 0.004 and 0.63) inC. citrinellum. The concentration in the liver was 0.79 g.g^–1±1.29 inC. managuense and 0.62 g.g^–1±0.44 inC. citrinellum. Human hairs (n=98) of fishermen and their families contained 5.03 g.g^–1±6.2 (extreme values 0.02 and 38.22). The mean concentration measured in men was 6.22 g.g^–1±6.34 (n=58), and in women 3.39 g.g^–1±5.7 (n=40). The average mercury concentration of hairs of workers of ELPESA was 91.24 g.g^–1±156.9 (extreme values 0.46 and 724.53; n=32). We conclude that total mercury levels in the various ecosystem compartments are very high and mercury contamination in the lake may be considered as dangerous for human health.     

Allometry of aboveground biomasses in mangrove species in Itamaracá, Pernambuco, Brazil

Allometric equations to estimate aboveground biomass (AGB) and plant part biomasses (PPB) of three mangrove species, Rhizophora mangle, Avicennia schaueriana, and Laguncularia racemosa, were determined in Itamaracá, Pernambuco, Brazil (7°48′44″S and 34°49′39″W). Twenty-three to thirty-six trees of each species, ranging in height (H) from 1.6 to 11.8 m and in diameter, at breast height or above prop roots (D), from 2 to 21 cm, were measured, cut, and separated into stems, branches, leaves, and prop roots. Biomass proportions in each tree part were similar among species, excluding prop roots: stems 37–47%, branches 41–46%, and leaves 11–17%. Prop roots represented 37% of AGB in R. mangle. Tree size had a significant but not large influence on biomass distribution among plant parts: as stem diameters increased the proportions allocated to leaves decreased and those to stems and branches increased. AGB and PPB were significantly related to D and D² × H and the best fittings were obtained with power equations. A few equations from literature fitted the data reasonably well for AGB of one or two of the species but resulted in large errors for the others. Applying the equations to previous measurements of tree diameters in a sample area, AGB for the mangrove site was estimated at 105 Mg ha⁻¹, with 78, 19, and 3% corresponding to biomasses of R. mangle, L. racemosa, and A. schaeuriana trees, respectively.     

Plant management and biodiversity conservation in Náhuatl homegardens of the Tehuacán Valley,Mexico

Background

The Tehuacán Valley is one of the areas of Mesoamerica with the oldest history of plant management. Homegardens are among the most ancient management systems that currently provide economic benefits to people and are reservoirs of native biodiversity. Previous studies estimated that 30% of the plant richness of homegardens of the region are native plant species from wild populations. We studied in Náhuatl communities the proportion of native plant species maintained in homegardens, hypothesizing to find a proportion similar to that estimated at regional level, mainly plant resources maintained for edible, medicinal and ornamental purposes.

Methods

We analysed the composition of plant species of homegardens and their similarity with surrounding Cloud Forest (CF), Tropical Rainforest (TRF), Tropical Dry forest (TDF), and Thorn-Scrub Forest (TSF). We determined density, frequency and biomass of plant species composing homegardens and forests through vegetation sampling of a total of 30 homegardens and nine plots of forests, and documented ethnobotanical information on use, management, and economic benefits from plants maintained in homegardens.

Results

A total of 281 plant species was recorded with 12 use categories, 115 ornamental, 92 edible, and 50 medicinal plant species. We recorded 49.8 ± 23.2 (average ± S.D.) woody plant species (shrubs and trees) per homegarden. In total, 34% species are native to the Tehuacán Valley and nearly 16% are components of the surrounding forests. A total of 176 species were cultivated through seeds, vegetative propagules or transplanted entire individual plants, 71 tolerated, and 23 enhanced. The highest species richness and diversity were recorded in homegardens from the CF zone (199 species), followed by those from the TRF (157) and those from the TDF (141) zones.

Conclusion

Homegardens provide a high diversity of resources for subsistence of local households and significantly contribute to conservation of native biodiversity. The highest diversity was recorded in homegardens where the neighbouring forests had the least diversity, suggesting that management of homegardens aims at compensating scarcity of naturally available plant resources. Cultivated species were markedly more abundant than plants under other management forms. Diversity harboured and management techniques make homegardens keystones in strategies for regional biodiversity conservation.

     

Hormonal correlates of siblicide in Galápagos Nazca boobies

Nazca boobies (Sula granti) show unconditional obligate siblicide immediately after hatching, reducing the typical two-egg clutch size to one. We studied body mass changes and levels of testosterone (T), corticosterone (CORT), and progesterone (P) for A-chicks (dominant, first hatched), B-chicks (subordinate, second hatched), and singletons, during the first 7 days after hatching, when siblicide normally occurs. Mass increase with age was higher for A-chicks than for singletons and B-chicks. This exaggerated the existing developmental advantage of A- over B-chicks that is due to hatching asynchrony. In nests with two chicks, CORT titer was significantly higher in B-chicks than in A-chicks. During ontogenetic development, CORT decreased with age for A-chicks, but did not change for singletons. P showed qualitatively similar ontogenetic changes to CORT, remaining unchanged for A-chicks but increasing for singletons. Thus, both CORT and P levels were lower for A-chicks than for singletons, and both hormones varied inversely with body mass. Overall, T levels did not differ between different categories of chicks. However, one B-chick in the process of reversing the dominance relationship with its older, but weakened, sibling had significantly elevated T. We suggest that CORT and P are regulated to promote exaggerated mass gain in socially challenged A-chicks, facilitating siblicide. Whether T induces aggressiveness during short time intervals of intense sibling rivalry needs further attention.     

Prion protein gene polymorphisms in sheep in the state of Paraná, Brazil

To determine the polymorphisms of the prion protein gene in sheep from the state of Paraná, Brazil, 323 animals of meat breeds (Suffolk, Hampshire Down, Texel, Ile de France, Dorper, Dorset, Santa Inês and crossbreds) were genotyped by restriction fragment length polymorphism (RFLP) analysis. The most frequent allele was ARQ, with a frequency of 0.61, followed by ARR (0.30). VRQ and AHQ alleles were present at very low frequencies (0.13 and 0.05 respectively), and the ARH allele was not found. Seven genotypes were identified (ARR/ARR, ARR/ARQ, ARQ/ARQ, ARR/VRQ, ARR/AHQ, ARQ/VRQ and ARQ/AHQ), of which ARQ/ARQ was the most frequent (0.41). The Santa Inês breed and crossbred animals showed the highest genotypic variability.     

Topographic position affects the water regime in a semideciduous tropical forest in Panamá

The effects of topographic position on water regime in a semideciduous tropical forest on Barro Colorado Island in Panamá were assessed by measuring soil matric potential using the filter paper technique and by using measured soil water release characteristics to convert a long-term (20 years) gravimetric water content data-set to matric potential. These were also compared against predictions from a simple water balance model. Soil matric potentials on slope sites were significantly higher than on plateau sites throughout the measurement interval and slopes experienced a shorter duration of drought during the annual dry-season. Measured values of matric potential agreed with those predicted from converting the gravimetric measurements using water release characteristics. Annual duration of drought predicted by the simple water balance model agreed with values determined from the converted long term water content data-set and was able to predict the annual duration of drought on plateau sites. On slope sites, the water balance systematically and significantly overestimated the duration of drought obtained from the water content data-set, suggesting that slope sites were supplied with water from upslope. Predictions of annual drought duration from sites with higher annual rainfall than Barro Colorado Island (BCI), suggest that while plateau sites on BCI experience a water regime consistent with annual rainfall, slopes experience a water regime more similar to that of forests with much higher rainfall. We conclude that such large variations in water regime over small spatial scales may play a role in maintaining high species richness through providing opportunities for niche specialisation and by buffering slopes against possible climate change.     

Traditional Knowledge and Useful Plant Richness in the Tehuacán–Cuicatlán Valley,Mexico

Traditional Knowledge and Useful Plant Richness in the Tehuacán–Cuicatlán Valley, Mexico. This study systematizes ethnobotanical information about the interactions between people and plants, ethnofloristic richness, the relative importance of useful species richness in relation to general species richness, and plant management in the Tehuacán–Cuicatlán Valley of central Mexico. The study recorded a total of 1,605 useful vascular plant species (61.2% of the total species richness of the regional vascular flora), this being the region with the highest absolute richness of useful plant species in Mexico. The null hypothesis that plant families with a higher number of useful species would be those having a higher general species richness was analyzed through residuals method. The plant families richest in useful species were Poaceae, Asteraceae, Cactaceae, Cyperaceae, Mimosaceae, and Solanaceae, most of which also have the highest general floristic richness. However, analyses of use categories did not generally corroborate our hypothesis. About 1,335 of the useful species are wild, more than 500 species are submitted to some type of management (62 species are tolerated, 34 protected, 50 enhanced, and 358 cultivated), but only a few have been studied to document their process of domestication. This information can be useful for developing regional strategies of sustainable management of plant resources.     

A malignus melanoma immunterápiájának lehetoségei

Despite their well-documented immunogenicity, malignant melanomas belong to the most aggressive tumor types. A potential explanation for this is the suboptimal activation of tumor infiltrating T cells. In order to boost immune responses against tumors, a variety of treatment modalities have been tested in animal models and in clinical setting. Antigen-nonspecific approaches (e.g., IFN-alpha and IL-2), as well as active specific immunotherapeutical modalities based on the use of autologous or allogeneic tumor cell-save been investigated in clinical trials of melanoma. The identification of melanoma-associated antigens has opened new avenues in antigen-specific immunotherapy. A promising alternative for the delivery of different forms of melanoma antigens is the application of dendritic cells, the most potent antigen presenting cells capable of eliciting efficient T-cell response. Beside active immunotherapy, immune response against melanoma antigens could be increased through the adoptive transfer of tumor infiltrating lymphocytes or antigen specific T-cell clones. The most important conclusion that can be drawn from the results of published immunotherapy studies is that these modalities are able to induce durable complete tumor regressions,mostly with reasonable toxicity; however, generally only in a minority of patients. This points to the importance of appropriate patient selection, with regard to the expression of the targeted antigens and HLA molecules, as well as to the general immunocompetence of the patients. A crucial and still unsolved question is monitoring immune activation during treatment, although there are promising new tools that could prove useful in this respect. The presence of tumor-reactive CTL in the circulation or in the tumors does not guarantee an efficient immune response. It is important to assess if these T cells are in an activated and functional state. Finally, in several single target antigen-based clinical studies a therapy-induced immunoselection of antigen-negative clones, leading to disease progression, was observed. This could be overcome with the use of antigen cocktails or whole tumor approaches. A better understanding of the mechanisms of action of immunotherapeutical modalities may enhance the success rate of these strategies.     

Correlation of Candida species and symptoms among patients with vulvovaginal candidiasis in Maringá, Paraná, Brazil

Vulvovaginal candidiasis (VVC) is an infection caused by abnormal yeast growth in the mucosa of the female genital tract which is commonly diagnosed in gynecology. The aim of this study was to correlate the frequency of yeasts and their respective species in asymptomatic women with different clinical manifestation of VVC; evaluate possible relationships between number of fungus colonies and symptoms in this pathology. All patients who visited the laboratory within a period of five months, for routine examinations of vaginal secretion, independent of the presence or absence of symptoms of VVC were included in this study. Of these, women with immunodeficiency or with an infection of the genital tract by another agent were excluded. Candida albicans was the most frequently yeast isolated (60%). Among non-C. albicans yeasts, 61.5% were isolated of the asymptomatic women, 38.7% from patients with VVC and 11.1% of those from patients with RVVC. C. albicans was associated with symptoms of VVC and while, the presence of non-C. albicans yeasts with asymptomatic women. However, there was no association between the number of fungal colonies and symptoms.     

Report of Xiphophorus hellerii in the arid Metztitlán Canyon Biosphere Reserve in Mexico

Biosphere reserves have been established around the world as a means to protect sensitive or threatened ecoregions and the biodiversity within them. As such, the organisms occurring within these reserves are important from a conservation perspective as they often represent endemic species or remnant populations. Here we provide genetic evidence of widespread occurrence of Xiphophorus helleri within the Metztitlán Canyon Biosphere Reserve in Hidalgo, Mexico. One nuclear and two mitochondrial genes were sequenced from four populations within the canyon and confirmed that the specimens collected were X. hellerii. When compared to published sequences of X. hellerii from multiple localities within the documented natural range of the species, the specimens from Metztitlán were found to exhibit between 0 and 1.6 % sequence divergence. Possible scenarios for colonization of the canyon and conservation implications are discussed.     

A cryptic taxon of Galápagos tortoise in conservation peril

As once boldly stated, 'bad taxonomy can kill', highlighting the critical importance of accurate taxonomy for the conservation of endangered taxa. The concept continues to evolve almost 15 years later largely because most legal protections aimed at preserving biological diversity are based on formal taxonomic designations. In this paper we report unrecognized genetic divisions within the giant tortoises of the Galápagos. We found three distinct lineages among populations formerly considered a single taxon on the most populous and accessible island of Santa Cruz; their diagnosability, degree of genetic divergence and phylogenetic placement merit the recognition of at least one new taxon. These results demonstrate the fundamental importance of continuing taxonomic investigations to recognize biological diversity and designate units of conservation, even within long-studied organisms such as Galápagos tortoises, whose evolutionary heritage and contribution to human intellectual history warrant them special attention.