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Dendrograma que relaciona los sitios de estudio analizados conforme al índice de similitud de Sørensen. SO1 y SO2: zonas suroriente 1 y suroriente 2, A13: área de amortiguamiento 13.
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We evaluated the plant richness and conservation value of three areas recently added to the territory of the Pedregal de San Ángel Ecological Reserve: two of them added to the Southeastern core area (SO1 and SO2), and one to the buffer zone called A13. Cumulative plant richness was 199 species (57.6% of the species previously recorded in the litera...
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We evaluated the plant richness and conservation value of three areas recently added to the territory of the Pedregal de San Angel Ecological Reserve: two of them added to the Southeastern core area (SO1 and SO2), and one to the buffer zone called A13. Cumulative plant richness was 199 species (57.6% of the species previously recorded in the litera...
Citations
... Hence, availability of detailed biodiversity data at local scales is critical for supporting these approaches and for implementation of specific conservation strategies. Given limited conservation resources, assessing conservation values of individual PAs, including determining the relative ranks for conservation priority of PAs, is crucial for prioritizing conservation efforts (Cano-Santana et al., 2008) and identifying key PAs (Schultze et al., 2014). In particular, species in PAs in spatially heterogeneous regions vary in their richness or protection levels, which places different demands on conservation efforts (Wheeler et al., 2019). ...
Evaluation of conservation priorities in existing protected areas (PAs) is critical for effective allocation of limited conservation resources and optimization of PA structure. Traditional approaches of prioritizing within existing PAs are based on individual-scoring and complementarity-based algorithms, and are often guided by individual natural features rather than complementarity among PAs. However, the efficiencies of synthesizing individual-scoring and complementarity-based algorithms in prioritizing PAs are still unknown. Here, we implemented three algorithms for prioritizing 42 Nature Reserves (NRs) in Yunnan Province, China, including an individual-scoring algorithm (ISA), species-number complementarity algorithm (SNCA), and a new species-value complementarity algorithm (SVCA) which synthesized the former two algorithms. Subsequently, the species number and species conservation value evaluated the efficiencies of three algorithms and explored their implications in conservation planning. We found that the spatial distribution of priority levels of NRs varied in different biogeographical regions, and that most of the national NRs received higher conservation priorities than provincial NRs in all three algorithms. Additionally, the average species number conservation efficiency in SNCA was 3.45 and 1.61% higher than in ISA and SVCA, respectively, while the average species conservation value efficiency in SVCA was 1.83 and 3.37% higher than in SNCA and ISA. These results indicated that SNCA could protect more species at a minimum cost if conservation planning was aimed only at protecting the number of species. However, when species conservation value is the focus of conservation planning, SVCA was more cost-effective. Our analysis supports efforts at efficient allocation of conservation resources in individual PAs and entire PA network at different biogeographical scales, and informs decision-makers on leveraging cost-effective conservation efforts in the future.
Community structure of soil arthropods associated to Pittocaulon (Senecio) praecox was investigated in two sites with different vegetal cover in El Pedregal de San Ángel Ecological Reserve, South of Mexico City during thirteen-month period. The relationship of composition and abundance with soil variables was studied. A total of 101 483specimens belonging to 28 taxa and 191 morphospecies were collected in both sites (Open site: Abundance: 60,369, 27 taxa and 181 morphospecies; Closed site: 41 114, 26 taxa and 179 morphospecies), the value of Shannon's diversity index was marginally higher in Closed site (H'=3.67) than in Open site (H'=3.59), according to a modified t-test for comparing indexes (t91418=9.6946; p<0.001). Most abundant groups in both sites were Cryptostigmata and Prostigmata, with variations during the study period. The highest amount of specimens was recovered during the rainy season (May-October). The most abundant guilds recorded in both sites were predators, fungivores, detritivores and herbivores. The composition and trophic guilds of edaphic arthropods in the sites were affected by the microhabitat characteristics due to soil characteristics. According to a two-way ANOVA test, a significant effect due to site (F1,286=17.85, p<0.001) and month (F12,286=22.68, p<0.001) on the density of edaphic arthropods was recorded, but no significant differences in abundance were found when the interaction between both variables (F12,286=0.77, p>0.05) was considered. The RDA shows that the soil variables explain 23.5% of the variation observed in the distribution of species, and that variation is related mainly to the presence of K, P, Na and Mg, and groups of predator arthropods are more related to the aforementioned variables, while detritivorous groups are more related to MO, N contents, relative humidity and pH. The microenvironmental characteristics recorded in both sites can explain differences in composition and abundance of soil arthropods.
The bulbs and aerial parts of Zephyranthes concolor (Lindl.) Benth. & Hook. f. (Amaryllidaceae), an endemic species to Mexico, were found to contain the alkaloids chlidanthine, galanthamine, galanthamine N-oxide, lycorine, galwesine, and epinorgalanthamine. Since currently only partial and low resolution (1)H-NMR data for chlidanthine acetate are available, and none for chlidanthine, its 1D and 2D high resolution (1)H- and (13)C-NMR spectra were recorded. Unambiguous assignations were achieved with HMBC, and HSQC experiments, and its structure was corroborated by X-ray diffraction. Minimum energy conformation for structures of chlidanthine, and its positional isomer galanthamine, were calculated by molecular modelling. Galanthamine is a well known acetylcholinesterase inhibitor; therefore, the isolated alkaloids were tested for this activity. Chlidanthine and galanthamine N-oxide inhibited electric eel acetylcholinesterase (2.4 and 2.6 × 10(-5) M, respectively), indicating they are about five times less potent than galanthamine, while galwesine was inactive at 10(-3) M. Inhibitory activity of HIV-1 replication, and cytotoxicity of the isolated alkaloids were evaluated in human MT-4 cells; however, the alkaloids showed poor activity as compared with standard anti-HIV drugs, but most of them were not cytotoxic.
Through the seedling emergence method we studied the effects of fi re on the soil seed bank of a xerophytic shrubland in two consecutive years. We compared its composition and abundance in two sites, one burned and one unburned. An important proportion of seeds died due to the high temperatures reached by fi re. In addition, species richness and, diversity were also negatively affected. These variables showed statistical differences between sites and years. After one year, seed bank abundance and diversity reached higher values. Dominant species were perennial herbs in terms of species number, and in terms of seedling abundance the dominant life form was a tree. However, fi re was not a determinant factor in terms of species composition. These results are important to explain the changes in vegetation after a fi re, specially if we consider that this site is a natural preserve immersed in an urban area.
