墨西哥Selva Lacandona地区碳通量和土地利用/土地覆被变化格局

本文基于20世纪70年代的土地利用/土地覆被地图和90年代的卫星影像,估计了墨西哥恰帕斯selva Lacandona地区3个亚区的土地利用/土地覆被变化以及相关的碳通量。郁闭林的总面积减少了31%,然而次生林扩大了9倍多,次生灌木扩大了几乎6倍,耕地和牧场面积分别扩大了21%和92%。然而,在整个研究区域,土地利用/土地覆被变化并不是均一分布的。总的平均碳密度范围从郁闭成熟林的452Mg C/hm^2到牧场的120Mg C/hm^2。估计变化剧烈的地区损失了1976年总碳库的24%,然而受影响较少的地区仅损失了3%。

Long-term trends in a forest ungulate community: park establishment increases numbers, but poaching is a constant threat

DEAR EDITOR Deforestation represents one of the greatest threats to tropical forest mammals, and the situation is greatly exacerbated by bushmeat hunting. To construct informed conservation plans,information must be gathered about responses to habitat degradation, regeneration, and hunting over a sufficiently long period to allow demographic responses.

Importance of Quercus spp.for diversity and biomass of vascular epiphytes in a managed pine-oak forest in Southern Mexico

Background:Forestry management modifies the diversity,structure,and functioning of intervened forests.Timber extraction reduces tree density and basal area,leading to changes in the communities of vascular epiphytes.The objective of this study was to evaluate the diversity and biomass of vascular epiphytes in Quercus trees remaining in two pine-oak forest stands that have been subjected to two stages of the Silvicultural Development Method(release cutting,and thinning)in comparison with an unharvested old-secondary forest in southern Mexico.For each treatment,richness of epiphytes present on 60 oak trees was recorded and their dry biomass estimated.We calculated the true diversity(Hill numbers)and beta diversity using the Jaccard coefficient of similarity,and generated rank abundance curves per taxonomic epiphyte group(bromeliads,orchids,ferns and others).For each treatment,the relationships between overall diversity and epiphyte biomass to the host trees basal area were analyzed using log linear models.Results:We recorded a total of 67 species of epiphytes species belonging to 10 families hosted by five species of oaks.The greatest species richness(^(0)D)was recorded in the old-secondary forest.Fewer common(^(1)D)and dominant(^(2)D)species were recorded in the release cutting than in the other treatments.Epiphyte diversity and biomass were both slightly related to host tree basal area.Composition of epiphytes was similar(60%)among treatments,although orchids,bromeliads,and other families were more diverse in the old-secondary forest.Most bromeliad species were shared across all treatments,although orchids presented the most exclusive species in the unharvested forest.The bromeliad Tillandsia seleriana provided the greatest contribution to biomass in all treatments,followed by the orchid Camaridium densum.Generalized linear models indicated that epiphyte diversity was significantly related to treatment,and epiphyte biomass to basal area of host trees.Conclusions:Although forest management affects diversity,composition,and abundance of vascular epiphytes,most of their diversity and biomass can be maintained despite timber harvesting.This requires sparing some mature oaks during logging,as they contribute to conservation,establishment,and development of epiphytic communities,and maintaining untreated areas as a source of propagules for these communities.

High-quality reference genomes of swallowtail butterflies provide insights into their coloration evolution

Swallowtail butterflies(Papilionidae)are a historically significant butterfly group due to their colorful wing patterns,extensive morphological diversity,and phylogenetically important position as a sister group to all other butterflies and have been widely studied regarding ecological adaption,phylogeny,genetics,and evolution.Notably,they contain a unique class of pigments,i.e.,papiliochromes,which contribute to their color diversity and various biological functions such as predator avoidance and mate preference.To date,however,the genomic and genetic basis of their color diversity and papiliochrome origin in a phylogenetic and evolutionary context remain largely unknown.Here,we obtained high-quality reference genomes of 11 swallowtail butterfly species covering all tribes of Papilioninae and Parnassiinae using long-read sequencing technology.Combined with previously published butterfly genomes,we obtained robust phylogenetic relationships among tribes,overcoming the challenges of incomplete lineage sorting(ILS)and gene flow.Comprehensive genomic analyses indicated that the evolution of Papilionidae-specific conserved non-exonic elements(PSCNEs)and transcription factor binding sites(TFBSs)of patterning and transporter/cofactor genes,together with the rapid evolution of transporters/cofactors,likely promoted the origin and evolution of papiliochromes.These findings not only provide novel insights into the genomic basis of color diversity,especially papiliochrome origin in swallowtail butterflies,but also provide important data resources for exploring the evolution,ecology,and conservation of butterflies.

Olfactory response of Anastrepha striata （Diptera： Tephritidae） to guava and sweet orange volatiles

The behavioral responses of virgin and mated female Anastrepha striata Schiner （Diptera： Tephritidae） to guava （Psidium guajava L.） or sweet orange （Citrus sinensis L.） were evaluated separately using multilure traps in two-choice tests in field cages. The results showed that flies were more attracted to guava and sweet orange volatiles than to control （unbaited trap）. The physiological state （virgin or mated） of females did not affect their attraction to the fruit volatiles. Combined analysis of gas chromatography coupled with electroantennography （GC-EAD） of volatile extracts of both fruits showed that 1 and 6 compounds from orange and guava, respectively elicited repeatable antennal responses from mated females. The EAD active compounds in guava volatile extracts were identified by gas chromatography-mass spectrometry （GC-MS） as ethyl butyrate, （Z）-3-hexenol, hexanol, ethyl hexanoate, hexyl acetate, and ethyl octanoate. Linalool was identified as the only antennal active compound in sweet orange extracts. In field cage tests, there were no significant differences between the number of mated flies captured by the traps baited with guava extracts and the number caught by traps baited with the 6-component blend that was formulated according to the relative proportions in the guava extracts. Similar results occurred when synthetic linalool was evaluated against orange extracts. From a practical point of view, the compounds identified in this study could be used for monitoring A. striata populations.

Diversity and seasonal variation of ground and understory spiders from a tropical mountain cloud forest

We made intensive samplings to study the seasonal response of spiders across different forest strata(ground and understory)in a tropical mountain cloud forest from Mexico.We sampled spiders from ten plots in six sampling events during the dry and rainy season,to analyze their abundance,structure(distribution of abundance among species),diversity and the response of the five dominant species at each stratum.Results demonstrated that seasonal patterns of spider communities differed among strata,revealing a complex spatiotemporal dynamic.Abundance,structure,diversity of ground spiders,as well as the responses of four dominant species at this stratum,showed low seasonal variations.In contrast,a strong seasonal variation was observed for the understory assemblage,with lowest abundance and highest diversity in the rainy season,and different assemblage structures for each season.Seasonal patterns of each assemblage seem linked to the responses of their dominant species.We found high co-occurrence among most of the ground dominant species with similar habitat use and with multivoltine patterns,contrasting with low co-occurrence among most of the understory dominant species with similar habitat use and univoltine patterns.Our results showed that the spiders’assemblages of tropical mountain cloud forest(opposed to what is found in temperate and boreal forests)increase their species richness with the height,and that their responses to seasonal change differ between strata.Management programs of these habitats should consider the spatial and temporal variations found here,as a better understanding of their ecological dynamics is required to support their sustainable management.