Carbon emissions from dryland shifting cultivation: a case study of Mexican tropical dry forest

The article considers the relation of shifting cultivation to deforestation and degradation, and hence its impacts in terms of carbon emissions and sequestration potential. There is a need to understand these relationships better in the context of international policy on Reduced Emissions from Deforestation and Forest Degradation (REDD+). The article reviews the way in which shifting cultivation has been incorporated in global and national estimations of carbon emissions, and assembles the available information on shifting cultivation in Tropical Dry Forests (TDF) in Mexico, where it is widely practiced. It then takes the case of two villages, Tonaya and El Temazcal, which lie within the basin of the River Ayuquila in Jalisco, Mexico. Field data for the typical carbon stocks and fluxes associated with shifting cultivation are compared with stocks and fluxes associated with more intensive agricultural production in the same dry tropical forest area to highlight the carbon sequestration dynamics associated with the shortening and potential lengthening of the fallow cycles. The biomass density in the shifting cultivation system observed can reach levels similar to that of old growth forests, with old fallows (>20 years) having higher carbon stocks than old growth forests. Per Mg of maize produced, the biomass-related emissions from shifting cultivation in the traditional 12 year cycle are about three times those from permanent cultivation. We did not, however, take into account the additional emissions from inputs that result from the use of fertilizers and pesticides in the case of permanent agriculture. Shortening of the fallow cycle, which is occurring in the study area as a result of government subsidies, results in higher remaining stocks of carbon and lower emissions at the landscape level

Opportunities, Constraints and Perceptions of Rural Communities Regarding Their Potential to Contribute to Forest Landscape Transitions Under REDD+: Case Studies from Mexico

In Mexico, REDD+ is being presented as a win-win policy enabling forest communities to benefit financially and diversify their income sources while preserving and increasing their forest carbon stocks through more sustainable management. Under the national programme, it is expected that forest communities will have opportunities to tailor their own approaches. However, to date there is little understanding about what opportunities and constraints exist in reality for forest communities to contribute to REDD+, and even less about how their members perceive these opportunities. We assess potential and constraints at community level and investigate perceptions about opportunities in REDD+ and strategies that communities are currently envisaging for participation, in seven communities in the Ayuquila River Basin and around the Chamela-Cuixmala Biosphere Reserve in Jalisco, and in the area surrounding the Monarch Butterfly Reserve in Michoacan. We find that there is more opportunity for reduced degradation and forest enhancement than for reduced deforestation, in all the communities; that it may be difficult to establish additionality for REDD+ activities in some communities; that the amount of forest resource per community may greatly affect the potential to participate; that the presence of people with no land rights may complicate the distribution of benefits; that communities expect REDD+ in general to follow the Payment for Environmental Services model, and that lack of information about what activities may count as REDD+ activities and what level of financial rewards may be expected mean that communities cannot at present adequately appraise whether REDD+ will be worth their while or no

Nesting behavior of the lilac-crowned parrot

Nesting behavior of the Lilac-crowned Parrot (Amazona finschi) was observed over a three year period at 24 nests in the tropical dry forest of the Chamela-Cuixmala Biosphere Reserve, western Mexico. Nest site characteristics and the pattern of parental care throughout the nesting cycle are described for this mainland Amazon parrot and compared with that reported for other Amazon parrot species. Nest sites were located in natural cavities of large mature trees characteristic of semi-deciduous forest. Nest sites were similar to one another in tree species, tree size, cavity height, and entrance width, indicating that Lilac-crowned Parrots may select nest sites based on these characteristics. Unlike most parrot species, Lilac-crowned Parrots showed low nest site reuse and high synchrony of nest initiation. Throughout the nesting cycle, females and nestlings were fed only twice a day on average. Nest attendance during feeding visits was short. The infrequent feeding visits and short nest attendance exhibited by Lilac-crowned Parrots corresponds with that found for other mainland Amazon parrots in northeastern Mexico, but contrasts with the multiple feedings and longer nest attendance observed for island Amazon species. The distinct aspects of Lilac-crowned Parrot nesting behavior may be related to predation rate and food resource availability during the extreme dry season

El valor de las emisiones de carbono asociadas al sistema agrícola de roza, tumba y quema

A large part of Mexico´s forests are degraded but present the opportunity for recuperation of carbon stocks through natural growth, once the drivers of degradation are removed. However, there are opportunity costs involved since most of the drivers are related to economic activities including shifting cultivation and cattle grazing. The study calculates the economic costs of sequestration of carbon in tropical dry forest (TDF) in western Mexico based on an analysis of such opportunity costs. Results may help policy makers and land managers make informed decisions about whether to engage in international programs such as Reduced Emissions from Deforestation and forest Degradation (REDD+)

History of nonnative Monk Parakeets in Mexico.

Nonnative Monk Parakeets have been reported in increasing numbers across many cities in Mexico, and were formally classified as an invasive species in Mexico in late 2016. However, there has not been a large-scale attempt to determine how international pet trade and national and international governmental regulations have played a part in colonization, and when the species appeared in different areas. We describe the changes in regulations that led the international pet trade market to shift to Mexico, then used international trade data to determine how many parakeets were commercially imported each year and where those individuals originated. We also quantified the recent increases in Monk Parakeet (Myiopsitta monachus) sightings in Mexico in both the scientific literature and in citizen science reports. We describe the timeline of increased reports to understand the history of nonnative Monk Parakeets in Mexico. As in other areas where the species has colonized, the main mode of transport is through the international pet trade. Over half a million Monk Parakeets were commercially imported to Mexico during 2000-2015, with the majority of importation (90%) occurring in 2008-2014, and almost all (98%) were imported from Uruguay. The earliest record of a free-flying Monk Parakeet was observed during 1994-1995 in Mexico City, but sightings of the parakeets did not become geographically widespread in either the scientific literature or citizen science databases until 2012-2015. By 2015, parakeets had been reported in 97 cities in Mexico. Mexico City has consistently seen steep increases in reporting since this species was first reported in Mexico. Here we find that both national and international legal regulations and health concerns drove a rise and fall in Monk Parakeet pet trade importations, shortly followed by widespread sightings of feral parakeets across Mexico. Further monitoring of introduced Monk Parakeet populations in Mexico is needed to understand the establishment, growth and spread of introduced populations

Monk parakeet reports in time and space.

<p>Text labels and colored bubbles indicate reports of Monk Parakeets in cities during particular years; text labels indicate a report in the scientific literature, and is linked to the citation (see below), while bubbles indicate citizen science reporting (colored by region and log-scaled by number of reports made in a particular city in a particular year). For both citation text labels and citizen science bubbles, the location at which they are plotted indicates the city and year in which observations occurred. Thus, Monk Parakeets may have been reported in just the scientific literature in a city during a year (only text label), reported in just the citizen science database (only colored bubble), reported in both the scientific literature and by citizen scientists (text label and bubble), or not reported at all (blank). Each text label corresponds to a particular citation in the scientific literature, as follows: <i>A</i> [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0184771#pone.0184771.ref041" target="_blank">41</a>], <i>B</i> [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0184771#pone.0184771.ref042" target="_blank">42</a>] (not plotted, lack of information about observation), <i>C</i> [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0184771#pone.0184771.ref043" target="_blank">43</a>], <i>D</i> [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0184771#pone.0184771.ref044" target="_blank">44</a>], <i>E</i> [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0184771#pone.0184771.ref045" target="_blank">45</a>], <i>F</i> [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0184771#pone.0184771.ref046" target="_blank">46</a>], <i>G</i> [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0184771#pone.0184771.ref047" target="_blank">47</a>], <i>H</i> [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0184771#pone.0184771.ref048" target="_blank">48</a>], <i>I</i> [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0184771#pone.0184771.ref049" target="_blank">49</a>], <i>J</i> [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0184771#pone.0184771.ref050" target="_blank">50</a>], <i>K</i> [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0184771#pone.0184771.ref051" target="_blank">51</a>] (not plotted, year of sightings is unclear), <i>L</i> [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0184771#pone.0184771.ref052" target="_blank">52</a>], <i>M</i> [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0184771#pone.0184771.ref053" target="_blank">53</a>], <i>N</i> [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0184771#pone.0184771.ref054" target="_blank">54</a>], <i>O</i> [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0184771#pone.0184771.ref055" target="_blank">55</a>], <i>P</i> [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0184771#pone.0184771.ref056" target="_blank">56</a>], <i>Q</i> [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0184771#pone.0184771.ref057" target="_blank">57</a>], <i>R</i> [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0184771#pone.0184771.ref058" target="_blank">58</a>], <i>S</i> [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0184771#pone.0184771.ref059" target="_blank">59</a>] (not plotted, year of observation not specified), <i>T</i> [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0184771#pone.0184771.ref060" target="_blank">60</a>] (not plotted, years of study listed as 2009–2015, but years of parakeet observations not specified), <i>U</i> [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0184771#pone.0184771.ref061" target="_blank">61</a>]. The grey vertical line indicates the year the ban on pet trade of native parrots was passed.</p

Mexican cities with reported Monk Parakeet sightings, by region.

<p>Points indicate cities in which at least one reported sighting was entered into online citizen science databases or in a published scientific report, during 1999–2015. Mexico state shapefiles were downloaded from the GADM database of Global Administrative Area (version 2.8, available at s<a href="http://www.gadm.org/download" target="_blank">http://www.gadm.org/download</a>, Mexico, level 1) and mapped using the R package ‘maps’ [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0184771#pone.0184771.ref065" target="_blank">65</a>].</p

Citizen science reports summarized by geographic region.

<p>Citizen science reports summarized by geographic region.</p