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Dry tropical woodlands are the characteristic natural vegetation type of southeast Angola, where precipitation is seasonal and nutrient content of soils is very low. Subsistence farmers overcome the poor abiotic conditions by using shifting cultivation based on specific site selection. We describe the vegetation composition of a previously unstudied dense woodland tract, which is preferred for agriculture, comparing it to nearby open woodland. We placed 25 vegetation plots randomly in the two types of natural woodland vegetation (open and dense) as well as in fallows with three different durations of land use. In each plot the cover of all vascular plant species was recorded. Variables describing vegetation structure, including basal area and leaf area index, were recorded. We analyzed soil samples for texture, pH, conductivity and nutrients, and investigated the impact of land use duration on woodland regeneration. We found that species composition and vegetation structure of the dense woodland differed greatly from the surrounding open woodland. The dense woodland is preferable for agriculture because of its higher soil content of silt, clay and potassium, higher woody biomass, and more abundant soft litter. A longer duration of land use affects species composition and diversity of the regenerating vegetation as well as nutrient content in the soil. In the near future, the increasing demand for agricultural land is likely to change the structure and composition of the dense woodland.
Wbaneide Andrade Martins de, Marcelo Alves Ramos, Wedson Medeiros Silva Souto, José Severino Bento-Silva, Ulysses Albuquerque Paulino de, Elcida Araújo de Lima
We examined the known and practiced uses of licuri palm (Syagrus coronata) leaves by artisans and the dynamics of leaf collecting in the communities surrounding protected areas in northeastern Brazil. Through interviews, workshops, and guided tours, we assessed person-resource relationships and the varied influences on licuri uses in order to suggest measures for the sustainability of harvest practices. In total, 537 citations referring to the uses of the licuri palm were recorded, which resulted in 31 types divided into four categories: food, handicrafts, construction, and agriculture, with a correlation between the known and practiced uses. The relationship between people and the use of licuri is complex, but the multiple linear regression model showed that the known and practiced uses reflect mainly the influence of income (at least 32%), followed by age (at least 19%). Age, as a variable, can overcome the influence of the variable income to explain the practiced uses. Artisans obey the ordinance restricting leaf collecting to the annual removal of only 3 leaves per plant, but preparing the fiber involves other native forest species. This study indicates that people's responses to the imposed restriction can increase local conservation problems and that scientific studies are needed in order to adjust the guidelines and/or governmental policies for conservation of licuri palm. Such policies cannot be generalized throughout the region.
Ecological restoration encourages management for the complexity and heterogeneity of habitats, which are crucial for avian fauna structure. Two-year-old bird assemblages were evaluated based on diversity parameters of three different ecological restoration technologies applied in southern Brazil: passive restoration (PR), nucleation (NC) and high diversity plantation (HD). Richness, abundance and diversity were compared using ANOVA factorial design (three treatments × four seasons, with six samplings per season). The highest richness was observed for NC (49 ± 2.45 SD species) and the lowest richness occurred in the HD treatment (37 ± 3.14 SD species), with a similar statistical pattern for abundance and diversity (NC>PR>HD). NC responded favorably to the hypotheses of dynamic equilibrium, heterogeneity and habitat complexity, which are the probable mechanisms that influence primarily assemblage richness. Due to the presence of exclusive species for each treatment, we recommend the application of a mix of the different techniques tested to maximize the number of habitats and their interactions with birdlife.
Orangutans are highly endangered. In order to implement effective conservation strategies for these species, it is crucial to understand fully what constrains their distribution. Here, we use a previously developed time budget model to investigate the factors constraining the orangutans' ability to inhabit different areas of Borneo and Sumatra, as well as the social group size they are potentially able to adopt in their habitats. This model uses data from 13 field sites, together with climate and environmental data, to predict the amount of time individuals would need to spend in each of four main activities – feeding, moving, resting, and socializing. We found that resting time, which was linked to both dietary constraints and forest cover, was a key behavioral limitation on orangutan distribution. The maximum possible group size predicted for orangutans was low over the entire range, indicating that ecological constraints limit orangutan sociality, and that even small changes to habitat quality may further reduce the maximum possible group size. The fact that the values are already approaching one in many locations and are low throughout both Borneo and Sumatra, suggests that orangutans are vulnerable to extinction over their entire current distribution.
The Atlantic Forest is one of the most threatened biodiversity hotspots in the world due to habitat fragmentation. Restoration and connectivity of forest fragments are crucial to maintain viable populations of forest-dependent species. During winter and summer, we studied the bird diversity, its components and composition (including specialist and generalist species) in three different vegetation types: mature forest (MF), secondary forest (SF) and grassland (G) of an ecological corridor in Misiones, Argentina. We determined the influence of alpha diversity (of each habitat) and beta diversity (species turnover between habitats) on gamma diversity (regional diversity in the corridor), to provide conservation management recommendations. MF showed the highest values of bird diversity, richness, evenness and abundance, followed by SF and G, in both seasons. Only MF showed a possible seasonal variation in diversity and richness. The species composition of SF was similar to MF. However, G, where pasture specialist and edge species were the most common species recorded (70% of its avifauna), had very low similarity to MF, where the most forest specialist species were found (53%). As alpha diversities were higher than beta values, the bird diversity in the studied corridor mainly resulted from the diversity in each vegetation type, in both studied seasons. We therefore recommend preservation of both MF and recovering SF due to their high bird diversity and the presence of forest-dependent, threatened and endemic bird species. We also urge the creation of ecological corridors between protected forest remnants of the Atlantic Forest.
Non-invasive genetic sampling is increasingly being used for monitoring mammalian carnivore populations. However, environmental conditions in the tropics challenge researchers' ability to collect samples. We present the results of a preliminary study on the feasibility of using scent-baited hair traps for population monitoring of mammalian carnivores in Peninsular Malaysia. Stations were baited using either fatty acid scent or male cologne applied to hair traps. Video camera traps were also used to monitor carnivore reactions to the scent stations. We recorded 19 visits by seven carnivore species over 764 camera trap nights. Cheek-rubbing and scent-marking behaviour was recorded only for single individuals of two species: the Malayan tiger (Panthera tigris jacksoni) and clouded leopard (Neofelis nebulosa). This study suggests that scent-baited hair traps hold some promise for ecological issues requiring DNA analysis in Peninsular Malaysia. Additional research is needed to develop its full potential for conservation monitoring of large carnivores.
The Mayflower orchid, Laelia speciosa, is an endangered orchid endemic to oak forests of central Mexico. Because of extractive pressure on remaining natural populations, in vitro propagation has been proposed as an alternative for the massive propagation of this plant for conservation and commercial purposes. However, it is unknown whether this orchid will be able to tolerate the increased air temperature that is projected to occur during the present century, especially for in vitro propagated individuals at early developmental stages. A laboratory assay that measured electrolyte leakage, a common indicator of cell membrane integrity, was utilized to determine the high-temperature tolerance for 8-year-old individuals rescued from a wild population and for 2-year-old micropropagated individuals of the Mayflower orchid. The plants were incubated under day/night air temperatures of 25/15, 30/20, or 35/25 °C. Chlorophyll fluorescence measurements of the quantum yield of photosystem II (Fv/Fm) averaged 0.74 ± 0.01, except for the micropropagated individuals incubated under 35/25 °C, whose quantum yield of 0.64 ± 0.02 was indicative of stress. Electrolyte leakage also responded to incubation temperature. An observed increase of temperature tolerance of 0.6–1.0 °C per increased degree of incubation temperature indicates an ability to acclimate to rising air temperatures. However, the LT50 (the temperature that causes half of the maximum electrolyte leakage to occur) dramatically decreased (by 6.7–10.9 °C) for plants kept under 35/25 °C. In this case, the in vitro propagated individuals were less able to resist high air temperatures. It appears that the Mayflower will be able to survive climate change, provided that in vitro propagated individuals are sufficiently hardened.
We documented movement of a long-distant migrant (Swainson's Thrush Catharus ustulatus) and two understory resident species (Chestnut-capped Brush-finch Buarremon brunneinuchus and Streak-capped Treehunter Thripadectes virgaticeps) in a fragmented landscape dominated by a pasture matrix in a Sub-Andean region of central Colombia. Swainson's Thrush had no detectable difficulties traversing a pasture matrix and returning to the capture site. Chestnut-capped Brush-finch and Streak-capped Treehunter (understory resident species) avoided making lengthy flights and used stepping-stones and nearby corridors to ease their movement. Providing stepping stones such as live fences and isolated trees and maintaining corridors can enhance functional connectivity in regions with fragmented forests, aiding the conservation of bird species.
The role of plant diversity, particularly of rare species, in ecosystem functioning (e.g., carbon storage) has been mostly studied in temperate systems with little practical application to the conservation of tropical forests, where species rarity and species richness tend to be greater and more important for ecosystem functioning. We linked carbon storage pools with functional plant diversity, occurrence of rare species, and environmental (topographic) gradients in a species-rich seasonally dry tropical forest protected as a part of a Biosphere Reserve in northwestern Mexico. We estimated various functional diversity and carbon pool measures from in situ plant community and soil data. Soil and total ecosystem carbon storage decreased with slope steepness but increased with plant height. Above-ground carbon was negatively associated with elevation. Our data suggest that species identity matters to the functioning and productivity of seasonally dry tropical forests. Two long-lived and highly threatened rare plant species contributed considerably (10-20%) to the above-ground carbon storage pool. The functional roles of threatened plant species should be investigated and incorporated into the management plans of Biospheres Reserves and other closely coupled natural-human systems, where conservation plays a significant role in ecosystem functioning and human well-being.
Roads through protected areas are generally believed to have many adverse environmental effects but there are few examples of road building being halted for environmental reasons. In Katavi National Park, western Tanzania, plans to upgrade a murram road connecting regional capitals have been stopped in favour of retaining the sanctity of the protected area. Despite empirical evidence suggesting upgrading would damage trees, increase traffic, adversely affect large mammals, and result in more litter, the decision not to upgrade was likely made for general environmental and sociopolitical reasons rather than on consideration of ecological data per se. This suggests that conservation scientists, while remaining independent, need to work with politicians to achieve environmentally friendly outcomes regarding tropical highways.
Miguel Á. García-Martínez, Dora L. Martínez-Tlapa, Gibrán R. Pérez-Toledo, Luis N. Quiroz-Robledo, Gabriela Castaño-Meneses, Javier Laborde, Jorge E. Valenzuela-González
In tropical dry landscapes, biodiversity conservation is dependent upon both the protection of natural areas and the sustainable management of the agricultural matrix. We analyzed the taxonomic, species and functional group diversity of ants in three neighboring habitats with different degrees of anthropic disturbance in Veracruz, Mexico. A total of 34,957 ant workers belonging to 89 species, 34 genera, 19 tribes and 7 subfamilies were recorded. Primary forest had the highest species richness and most even distribution of species among the taxonomic levels, followed by secondary forest and active pasture. Because high species turnover among habitats increased species richness at the landscape level, the three neighboring habitats that we sampled are important for conservation biodiversity and together have a high conservation value for ants and probably for other invertebrates as well. Species of specialized functional groups were more frequent in primary forest, while those belonging to generalist and opportunistic groups were more frequent in active pasture. Human-disturbed areas in the vicinity of protected areas have an important role as reservoirs of biodiversity and should be included in landscape management practices designed to improve arthropod conservation in the tropics.
Clear-cutting has been a widespread commercial logging practice, causing substantial changes of biodiversity in many forests throughout the world. Forest recovery is a complex ecological process, and examining the recovery process after clear-cutting is important for forest conservation and management. In the present study, we established fourteen 20 m × 20 m plots in three recovery stages (20-year-old second growth, 35-year-old second growth and old growth) and explored the changes in evergreen and deciduous species diversity after clear-cutting in a subtropical evergreen-deciduous broadleaved mixed forest in central China. The results showed that total species richness was highest at the intermediate recovery stage. The species richness and stem abundance of evergreen species increased, while total and deciduous species stem abundance decreased with forest recovery. The basal area of both total and evergreen species increased, while that of the deciduous species showed a unimodal pattern. The abiotic conditions varied with the recovery process. Changes in species compositions were generally correlated with soil pH, total phosphorus, and CO. Our results suggest that deciduous species richness and stem abundance can recover after 20–35 years, but evergreen species need more time to recover following clear-cutting.
A large number of governance interventions are being developed in order to reduce deforestation and enhance the sustainability of commodity supply chains across the tropics. The extent to which individual agricultural commodity supply chain interventions can achieve scale, and environmental or social objectives, depends in part on the ways in which those interventions interact with other interventions. We use a case-study of the new Sustainable Agriculture Network (SAN) cattle certification program in Brazil to explore the different ways in which governance interventions interact. We examine the broad landscape of policies and programs that affect sustainability in the cattle supply chain in Brazil, and assess whether such interventions support or constrain the scaling up of the SAN cattle program. We conducted semi-structured interviews with key stakeholders from government, private sector, and civil society organizations. We found that multiple interventions are acting in a complementary manner to enhance sustainability and therefore enable the scaling up of the SAN program, by aiding compliance with environmental laws, adoption of good production practices, and improved monitoring. At the same time, limited development, implementation, and complementarity of some interventions could be antagonistic to the SAN program's expansion because they maintain a context in which many actors operate far below the sustainability criteria required by the program. Our holistic approach enables us to identify specific gaps in the complex landscape of governance interventions in Brazil. Greater strategic complementarity and coordination between interventions may catalyze a more coherent and effective pathway to reduced deforestation and enhanced sustainability.
Decentralised environmental governance has become a catchy solution to environmental problems caused by the failure of traditional centralised environmental governance. It promises to transfer power and authority, improve efficiency, equity, accountability, and inclusion of local people who were previously excluded by the command and control model. This paper examines the efficacy of decentralised environmental governance as an alternative approach to wildlife conservation in Tanzania. We analyse the policy and legal framework for Wildlife Management Areas (WMAs) in Tanzania over the past two decades as a case study on current practice and its implications. We find that despite the rhetoric of community-based conservation (CBC), the wildlife industry remains heavily under state control, while the promises of CBC remain elusive. Questioning the effectiveness of decentralised environmental governance through CBC, we recommend that actors return to the drawing board and re-negotiate their positions, interests, power and authority if meaningfully decentralised environmental governance is to be achieved.
This study evaluates the seizure of birds in the state of Amazonas during twenty years (1992-2011), providing information on the sale of birds in a state recognized for its significant biodiversity. We compiled a total of 2,698 seizure records of illegal wildlife trade, which were drawn up and issued by the Brazilian Institute of Environment and Renewable Natural Resources - IBAMA (the Brazilian official agency for environmental license and patrol) in the state of Amazonas, during 240 months. Reports of birds seized were found in only 297 (11%) of the seizure records analyzed. The number of bird specimens ranged from 3 to 710 per year, and the taxonomic richness ranged from 1 to 24 species. Considering all seizures, there was a richness of 40 bird species, distributed in 16 families and 10 orders. Among the families analyzed, Thraupidae was the richest, with 17 species, followed by Psittacidae, with eight species. The order Passeriformes was the most represented, with 12 genera, where Sporophila was the richest, with nine species (22.5% of total species). The Saffron Finch (Sicalis flaveola – Linnaeus, 1766), Muscovy Duck (Cairina moschata - Linnaeus, 1758) and Chestnut-bellied Seed-Finch (Sporophila angolensis - Linnaeus, 1766) together accounted for more than half (56.9%) of the total birds seized for the period. Of the species recorded in this study, five (12.5%) were listed as Endangered. Our results suggest that the illegal trade of animals in Amazonas shows a pattern different from that which has been reported in other Brazilian states. Birds were little represented in the Amazon, and the main reason for their illegal trade was related to their use as food. In addition to the cultural aspects, the richness of vertebrates in the Amazon certainly influences the choice of animals used and marketed in the Amazon region.
We compiled Red List data from all listed cycad taxa to determine the current status of the world's most threatened plant group. Each Red List threat category had different proportions of genera, and the genera comprised different proportions of threat categories. Each Red List threat category consisted of different proportions of Red List criteria. Each genus was composed of different proportions of Red List criteria, and every genus was represented by different proportions of listed versus non-listed species. Differences among the genera and categories were substantial, revealing no canonical characteristics that define the members of this plant group. Species that are missing from the Red List or Data Deficient deserve high priority for completion of assessment and listing. Cycas is the genus that may change the most as taxonomy and Red List threat assessments continue to be modified. Distinctive overviews of the Red List data such as this one provide a unique snapshot of the conservation status of the world's cycads, and should be repeated as trends evolve.
Ordinary least-square (OLS) regression is fundamental to quantitative research in many ecological disciplines. However, spatially explicit methods have recently been proposed that allow the incorporation of spatial autocorrelation into ecological models. We compared the spatial error simultaneous autoregressive model (SARerr) and generalized least squares regression (GLS) with the results of simple and multiple OLS regressions, to analyze the relationship between white-tailed deer (Odocoileus virginianus) population density and environmental conditions in two regions dominated by tropical dry forests in central Mexico. The spatially explicit methods presented better goodness of fit than the OLS regression; we also observed a miscalculation in the probabilities obtained with the OLS regression, which in this method led to an incorrect interpretation. In general, we suggest the application of spatially explicit methods to analyze species-habitat relationships when SAC is observed in model residuals. We also discuss the management implications of these results.
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