Juan M. Pech-Canché

Continuous forest has greater taxonomic, functional and phylogenetic plant diversity than an adjacent naturally fragmented forest

Several studies have evaluated the short-term effects of tropical forest fragmentation on plant taxonomic diversity, while only a few have evaluated its effects on functional or phylogenetic diversity. To our knowledge no study has looked at the long-term consequences of tropical forest fragmentation on the three main components of plant diversity simultaneously: taxonomic, functional and phylogenetic diversity. We sampled the vascular flora using belt transects (50 × 4 m) in a continuous tropical semi-evergreen forest (16 transects) and in an adjacent naturally fragmented forest (fragments of 1.7-My-old semi-evergreen forest immersed in a mangrove/sedge matrix) (18 transects), and compared their taxonomic, functional and phylogenetic plant diversity. There were 36 species in the continuous forest and 28 in the fragmented forest. Continuous forest was taxonomically more diverse (25%) than thefragmentedforest.All functionaldiversitymetrics were greater (6-33%)inthecontinuous thaninthe fragmented forest. Phylogenetic diversity was 19% greater and phylogenetically more overdispersed in the continuous forest than in the fragmented forest. The results suggest that in the fragmented forest not only is taxonomic plant diversity lower, but functional and phylogenetic diversity are as well. The negative effects of forest fragmentation on plant diversity seem to be chronic.

Additive Partitioning of Phyllostomid Bat Richness at Fine and Coarse Spatial and Temporal Scales in Yucatan, Mexico

Abstract: Neotropical bats exhibit great diversity in terms of resource use, so their species richness can vary both spatially and temporally over fine and coarse scales. In this paper we analyze the relative contribution of the alpha (a) and beta (&bgr;) components of bat species richness at different spatial and temporal scales in deciduous and semideciduous tropical forests in Yucatan, Mexico. We used different levels of the spatial (understory and subcanopy height, site, and vegetation type) and temporal (sampling period within a night, sampling night, and season) dimensions. For the spatial dimension, we found that the finer level (&agr;) accounted for more than 50% of total richness and was higher (72% of total richness) within the semideciduous tropical forest. Although lower than for a, the percentage contribution of &bgr; among sites and &bgr; between vegetation types was higher than expected by chance. For the temporal dimension, &agr; contribution was lower than 25% of total richness in all cases, while &bgr; at different time scales had a great influence on bat species richness. Our results indicate that the species composition of bat assemblages is dynamic in space and time. Thus, a proper assessment of diversity requires the inclusion of a variety of spatial and temporal scales in sampling designs.

Los pequeños roedores de la Península de Yucatán: conocimiento y perspectivas en 114 años de investigación

Studies conducted on small mammals, such as tropical rodents, have generated great interest since they can easily provide information concerning to their populations. The present article presents an analysis of the bibliography and sampling locations of small rodents of the Yucatan Peninsula in Mexico. In addition, the information contained within the literature is revised in order to identify the geographic and thematic coverage of the species records for the purpose of analyzing perspectives in the study of small rodents and in order to contribute to the efforts being made towards their protection and conservation. Publications of periodical journals, books and book chapters published between 1901 and 2015 were reviewed and analyzed. The literature covered research of the 15 small rodent species that are distributed on the Yucatan Peninsula. The studies were grouped into 10 themes, an accumulation curve was prepared by decade for each state of the Yucatan Peninsula and a map of distribution was generated detailing the locations of the records of each species. A total of 212 references were obtained, of which 162 corresponded to articles in periodical publications and 50 to books and book chapters. The most studied species were Peromyscus yucatanicus , Heteromys gaumeri and Ototylomys phyllotis ; in contrast, those for which practically no information exists were Tylomys nudicaudus , Reithrodontomys spectabilis and Heteromys desmarestianus . The State of Yucatan has been the most explored and has the greatest number of sites and records of small rodents, followed by Quintana Roo and finally Campeche. The most commonly addressed themes were distribution, taxonomy, phylogeny, diseases and parasitism. Gaps in the information were detected for the majority of the species in the different themes such as feeding, reproduction, anatomy and morphology. For this reason, it is important to carry out studies in these themes in order to further the knowledge of the small rodents of the Yucatan Peninsula. These studies could provide information with the aim to propose changes to their conservation status in both Mexican and international legislation, or take appropriate decisions regarding protection of their specific habitats. Key words: Campeche; diversity; Mexico; Quintana Roo; Rodentia.