Amphibians are the vertebrate group with the highest number of species threatened with extinction, and habitat loss and fragmentation are considered to be among the leading causes of their declines ...and extinctions. Little is known of the population biology of amphibian species inhabiting montane forests in Central and West Africa, where anthropogenic activities such as farming and cattle raising are major threats to native biodiversity. We used Amplified Fragment Length Polymorphisms (AFLPs) to assess the population genetic structure of two poorly known species, Cardioglossa schioetzi and Leptodactylodon bicolor (both in the Arthroleptidae), in and around Ngel Nyaki Forest Reserve on the Mambilla Plateau in eastern Nigeria. The landscape comprises continuous forest on steep slopes and small riparian forest fragments in a grassland matrix. While increased fragmentation is well documented for these and other forests in the mountains of Cameroon and Nigeria over the past century, there are no previous assessments of the impact of forest fragmentation on montane amphibian populations in this region. Our estimates of genetic diversity are similar across populations within each species with levels of heterozygosity values consistent with local population declines. Except for a pair of populations (C. schioetzi) we did not observe genetic differentiation between forest and riparian forest fragment populations, nor across sites within continuous forest (L. bicolor). Our results demonstrate recent gene flow between forest fragments and the adjacent protected forests and suggest that small forest corridors connecting these may lessen the genetic consequences of at least 30 years of intense and severe fragmentation in Ngel Nyaki.
As cities overgrow, the need for ecological restoration is becoming increasingly urgent, especially in densely populated areas. Urban ecological restoration represents the best approach to undertake ...damages to restore native ecosystem remnants fulfilling biodiversity but also social goals in dense urban settings such as Mexico City. The feasibility of restoring unique xerophytic scrub vegetation in lava field remnants was evaluated in a portion of a university campus in Mexico City. Here we present an index (Need and Feasibility of Restoration Index, NFRI) for such purpose. The NFRI was designed through multicriteria analysis and considered ecological, economic, and social indicators. Cluster and principal components analysis were carried out to identify different groups of lava field remnants with similar characteristics and to point out critical variables that in turn would support management strategies. The outcomes made evident the necessity of restoring native vegetation for all of the evaluated remnants; however, the group containing the largest ones obtained the highest values for restoration feasibility and NFRI. The recovery of the rest of the remnants is critical to support the ecological restoration of the area as this may provide connectivity with better-preserved ecosystem remnants. When the restoration is unaffordable due to financial constraints, it is highly recommended to direct efforts towards ecological rehabilitation actions. The establishment of native xerophytic gardens is promoted when remnants cannot support a self-sustainable plant community. It is crucial to include the diversity of views and values of the community and the economic and ecological aspects to guarantee the sustainability of the landscape, especially in the urban context. The latter can provide better planning and design processes, ensuring benefits for humans and nature.
The domestication syndrome of many plants includes changes in their mating systems. The evolution of the latter is shaped by ecological and genetic factors that are particular to an area. Thus, the ...reproductive biology of wild relatives must be studied in their natural distribution to understand the mating system of a crop species as a whole.
(upland cotton) includes both domesticated varieties and wild populations of the same species. Most studies on mating systems describe cultivated cotton as self-pollinated, while studies on pollen dispersal report outcrossing; however, the mating system of upland cotton has not been described as mixed and little is known about its wild relatives. In this study we selected two wild metapopulations for comparison with domesticated plants and one metapopulation with evidence of recent gene flow between wild relatives and the crop to evaluate the mating system of cotton's wild-to-domesticated complex. Using classic reproductive biology methods, our data demonstrate that upland cotton presents a mixed mating system throughout the complex. Given cotton's capacity for outcrossing, differences caused by the domestication process in cultivated individuals can have consequences for its wild relatives. This characterization of the diversity of the wild relatives in their natural distribution, as well as their interactions with the crop, will be useful to design and implement adequate strategies for conservation and biosecurity.
Despite the central role of microorganisms in soil fertility, little understanding exists regarding the impact of management practices and soil microbial diversity on soil processes. Strong ...correlations among soil microbial composition, management practices, and microbially mediated processes have been previously shown. However, limited integration of the different parameters has hindered our understanding of agroecosystem functioning. Multivariate analyses of these systems allow simultaneous evaluation of the parameters and can lead to hypotheses on the microbial groups involved in specific nutrient transformations. In the present study, using a multivariate approach, we investigated the effect of microbial composition (16SrDNA sequencing) and soil properties in carbon mineralization (CMIN) (BIOLOG™, Hayward, CA, USA) across different management categories on coffee agroecosystems in Mexico. Results showed that (i) changes in soil physicochemical variables were related to management, not to region, (ii) microbial composition was associated with changes in management intensity, (iii) specific bacterial groups were associated with different management categories, and (iv) there was a broader utilization range of carbon sources in non-managed plots. The identification of specific bacterial groups, management practices, and soil parameters, and their correlation with the utilization range of carbon sources, presents the possibility to experimentally test hypotheses on the interplay of all these components and further our understanding of agroecosystem functioning and sustainable management.
The current global situation with a dominant economic development model producing social inequality, increment and intensification of urbanization has generated severe environmental degradation and ...an associated increase in the likelihood of pandemics. New strategies that strengthen sustainable food production are urgent in highly unequal countries as Mexico. In Mexico City, the most populated city of the country, a wetland system, named Xochimilco, still holds
chinampas
, a unique and ingenious food system dating from pre-Hispanic times. These days
chinampas
are the best example of urban sustainable agriculture production. Unfortunately, this system is under threat due to urbanization and industrial land-use changes. Among the strategies to promote sustainable modes of production and consumption is eco or green labeling, consisting of a voluntary environmental certification approach, and marketing and advertising tool, that can change producers' and consumers' behavior toward long-term sustainability. Although widely used, the benefits of green labels for producers are not always realized. This study aimed to learn more about the agro-ecological production process and commercialization challenges in Xochimilco and San Gregorio Atlapulco in Southern Mexico City to understand
chinampa
producers' needs and determine whether a green label can offer solutions in this vulnerable socio-ecological system, particularly suffering the effects of the COVID-19 pandemics. For this, a literature review and producers' mental model analysis based on network theory, were developed. Results show that non-resolved issues such as commercialization problems, consumers' unwillingness to pay a fair price, loss of healthy soil, and degraded water quality used for irrigation persist and can affect the benefits of a green label including to improve
chinampa
production and farmers' income. Farmers' current necessities comprised increasing profits, receiving financial advice to set prices of agro-ecological vegetables and production costs, among others. Under the current production and commercialization scenarios complying with the assessment cost of certification will be difficult for most producers; then, implementing the green label would probably fail to fulfill the benefits. Attending to former and persistent conflicts and satisfying
chinampa
producers' neglected necessities are essential before implementing any program.
Incorporating the views and perceptions of local farmers and other actors with stakes in agricultural production is critical for better-informed decision making and tackling pressing issues, such as ...soil degradation. We conducted a study that sought to integrate and analyze perceptions regarding the quality and degradation of agricultural soils across different social sectors in Mexico, including producers of two annual crops (maize and beans) and two perennial crops (coffee and avocado), members of civil society organizations and members of the Federal Government. We analyzed the community perception using Cognitive Maps and network metrics. Our fully documented method to formally gather and analyze local and regional perceptions can be used in future efforts toward the collective design of sustainable food systems. Our results highlighted common and potentially conflicting aspects among the different perceptions and allowed us to identify and discuss drivers and processes of special interest in different regions in Mexico. This study also contributes to a deeper understanding of the current situation of agricultural soils in Mexico and seeks to inform the decision-making process regarding agricultural management in the country.
Protected urban green spaces (PUGS) are exposed to numerous disturbances and threats since they are immersed in highly dynamic socio-ecological systems. PUGS in highly urbanized cities require ...particular conservation strategies. Here, we propose an approach for PUGS management which integrates three components: i) scientific knowledge (monitoring/restoration), ii) community interaction with the environment, and iii) management decision. Our hypothesis asserts that the intersection of these components should produce a solid management program, provided that the obtained multidisciplinary knowledge meets the needs of information required by the community and decision makers. We tested this hypothesis for a small PUGS located within Mexico City at the National Autonomous University of Mexico campus that holds the Ecological Reserve of Pedregal de San Ángel. Through a participatory approach we built a mental model to understand the perceptions of different campus actors (students, academics and administrators), and their social and ecological relationships with this PUGS. Our findings provide insight into the actors’ perceptions and concerns and suggest that the interactions among the three components, although important, are not self-generated and must be constructed. The findings also suggest that one of the management problems is the mismatch between scientific knowledge and conservation programs. It is paramount to include generated knowledge into management and monitoring programs. The complexity of the PUGS requires an active collaboration among actors and monitoring the development of management strategies using the three components while taking the conservation goals into account.
•The intensity of management in agricultural crops can affect local biodiversity.•Caterpillar abundance and richness decreased as management intensity increased.•Low intensity management plantations ...had the lowest levels of foliar damage.•Shade coffee plantations can preserve lepidopteran communities.
Although the conservation potential of low input coffee plantations has been widely proved, the effect of management intensity on insect herbivores and particularly caterpillar communities has been scarcely studied. We used a management intensity quantitative index to assess changes in leaf damage, abundance of all herbivores and caterpillar species richness, abundance, evenness and community species composition along a management intensity gradient in coffee plantations.
There was no correlation between management intensity and the abundance of all herbivore guilds, but there was a negative relationship between management intensity and caterpillar abundance and species richness. Management intensity was positively related to caterpillar species evenness but did not influence species composition, which was rather influenced by climatic seasonality. We found 202 lepidopteran morphospecies, of which 128 fed on coffee plants. Despite a greater caterpillar abundance and richness, mean leaf damage to coffee plants was lower in plantations with a low management intensity index. Overall, we suggest that low and intermediate management intensity and the preservation of a diverse shade canopy can contribute to the conservation of Lepidoptera, without representing significant amounts of leaf damage to coffee plants.
Chinampería, a jeopardized precolonial agricultural practice, persists in the Xochimilco wetland, Mexico City. Agroecological chinampa production is a recognized UNESCO World Heritage Site, and ...contributes to the sustainability of both the urban wetland and the city. The ‘chinampa-refuge’ model (CRM) is a transdisciplinary effort to strengthen traditional agroecological practices and ecological restoration. Through an inter/transdisciplinary research framework, we addressed the model’s role in the sustainability of this socio-ecosystem concerning four significant drivers of the wetland’s transformation. The CRM has improved water quality locally, increased the suitable habitat for native aquatic biodiversity, and supported traditional agroecological practices, thus improving the quality and safety of food products. However, there are clear challenges regarding production and commercialization, some of which may be addressed through the strengthening of the social organization and collective action. However, other challenges are beyond the reach of chinampa producers’ efforts and the CRM, but are decisive in changing the degradation trends. In order to address these challenges, urgent and participatory government actions are needed based on the recognition of the causes of wetland degradation and the role of traditional chinampa production in its sustainability.
Nigeria is the most densely populated country in Africa and one of the most advanced economically in terms of both industry and soil and landscape utilization. This country is projected to have one ...of the largest urban growth rates by 2050. Thus, the demands of the rapidly increasing human population and its material consumption represent a severe threat to biodiversity. Nigeria has the highest deforestation rate of natural forest in the world, its original vegetation has largely been replaced by farming activities, urban development and other products of human activities. The principal causes of the decline and loss of biodiversity in Nigeria include human exploitation of natural resources, fragmentation of habitats and populations, conversion of wild areas to agriculture and other intensive human use and alterations in the structure and function of ecosystems. Amphibians are the vertebrate group with the highest number of species threatened with extinction and habitat loss and fragmentation are considered to be among the leading causes of their declines and extinctions. It has been recognized that one of the most severe problems in conservation biology is the scarcity of baseline data. Such lack prevents evaluation of the effect of the expanding anthropogenic impact and determination of potential population declines.
The mountains of eastern Nigeria, within Taraba State, are regionally important in terms of biodiversity and endemism, however, its herpetofaunal diversity has received little attention. Moreover, no studies have investigated how habitat loss and fragmentation may affect dispersal and gene flow among small and isolated amphibian populations, and in the absence of such studies attempts at amphibian conservation are compromised.
The aims of this project were threefold. Firstly, a comprehensive inventory of the amphibians and reptiles of Ngel Nyaki and Kurmin Danko Reserve on the Mambilla Plateau was compiled. The outcome, an annotated list of 21 amphibians and 11 reptiles, represent the most thorough inventory to date of the herpetofauna on the Mambilla Plateau. Based on this inventory four key anuran species were selected to conduct a population genetics study.
Secondly, molecular tools specifically AFLP markers were developed and used to analyze the genetic population structures of the four frog species Cardioglossa schioetzi, Leptodactylodon bicolor, Astylosternus sp. 1 and Astylosternus sp. 2. differing in geographic distribution and life history traits within the study area.
Thirdly, these species were assessed to understand dispersal and connectivity among fragmented and continuous populations on the Ngel Nyaki and Kurmin Danko Reserve. Genetic differentiation among the forest and the riparian fragment populations was observed for three of the target species, however, no significant genetic differentiation was detected among the populations located in continuous forest for any of the four frog species. In addition, geographic and genetic distances were not correlated significantly for any of the four target species, suggesting no isolation by distance at this fine geographic scale.
Results from both the inventory and the genetic population structure study revealed that the riparian forest fragments are of utmost importance for the persistence and migration of Cardioglossa schioetzi, and potentially for many other amphibian species. The new scientific findings are now part of the valuable baseline data on the diversity and genetic population structure of amphibian species in Ngel Nyaki and Kurmin Danko Forest Reserve. These results will better inform conservation managers who need to make decisions around management of montane habitat for amphibian species.
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