The PREDICTS project—Projecting Responses of Ecological Diversity In Changing Terrestrial Systems (www.predicts.org.uk)—has collated from published studies a large, reasonably representative database of comparable samples of biodiversity from multiple sites that differ in the nature or intensity of human impacts relating to land use. We have used this evidence base to develop global and regional statistical models of how local biodiversity responds to these measures. We describe and make freely available this 2016 release of the database, containing more than 3.2 million records sampled at over 26,000 locations and representing over 47,000 species. We outline how the database can help in answering a range of questions in ecology and conservation biology. To our knowledge, this is the largest and most geographically and taxonomically representative database of spatial comparisons of biodiversity that has been collated to date; it will be useful to researchers and international efforts wishing to model and understand the global status of biodiversity.

Fragmentation reduces habitat area, increases the number of habitat patches, decreases their size, and increases patch isolation. For arboreal mammals such as howlers (Alouatta palliata), canopy modifications from fragmentation processes could also negatively affect habitat quality. We analyzed changes in the composition and plant structure of 15 fragments (1-76 ha) and compared them with vegetation from a continuous tropical rain forest reserve (700 ha) in Los Tuxtlas, Mexico. At each site, we sampled 1000 m 2 of all trees, shrubs, and lianas with a diameter at breast height (DBH) ≥ 10 cm. We obtained estimates of species richness, density, and basal area for different ecological groups, DBH ranges, and top food resources for howlers. We used a stepwise multiple regression analysis to determine relationships between fragment characteristics (size, shape index, and isolation) and plant variables. Compared to continuous forest, fragments have altered composition and plant structure, with large trees absent from the canopy. The basal area of top food resources is higher in continuous forest. Fragment size is the best explanation for the differences in composition and plant structure. The largest fragments had greater basal area of top food resources and more large primary trees in the canopy. Overall, our results suggest that fragmentation altered the habitat quality for howlers.

Conservation and management of species require basic knowledge on their geographic distribution and abundance. Here, we propose a novel approach, based on the theory of the ecological niche, to model the spatial patterns of the white‐tailed deer Odocoileus virginianus population density in two regions of central Mexico (Balsas Basin and Tehuacán‐Cuicatlán Valley). We used an ecological niche model to generate binary geographic distribution maps of the white‐tailed deer in each region based on occurrence data and a set of environmental variables. Then, the centroid of the distributions was calculated in ecological space (niche centroid) and the multidimensional Euclidian ecological distance of each pixel to the niche centroid was estimated. Finally, for each region the distance to the niche centroid (DNC) was regressed against 14 independent occurrence points in each site containing white‐tailed deer density information to determine the function describing the DNC‐density relationship, which was used to generate maps describing the distribution of white‐tailed deer density. Our results indicated an inverse DNC‐density relationship in both regions (Balsas Basin: r2 = 0.90 and Tehuacán‐Cuicatlán: r2 = 0.76) that was validated via bootstrapping resulting in a predicting capacity of near 62% for Balsas Basin and 65% for Tehuacán‐Cuicatlán Valley. Our results suggest that the distance to the niche centroid method is a robust, science‐based correlative approach that resulted useful to predict the population density of the white‐tailed deer in a spatially explicit fashion. The proposed approach is suitable for predicting the distribution of density for white‐tailed deer for which occurrence data with accompanying density information exists, but relative abundance can also be estimated when no abundance data are available.

Habitat fragmentation is one of the principal threats to primates. Studies of primates in fragments usually conclude that fragmentation negatively affects some aspect of their biology or ecology. Nevertheless, the definition and quantification of fragmentation vary considerably among studies, resulting in contradictions and results that are difficult to interpret. We here 1) discuss the problems associated with the definition of habitat fragmentation and the ways of measuring it, 2) emphasize the importance of the concepts and methods from landscape ecology and metapopulation theory for the study of primates in fragmented landscapes, and 3) offer recommendations for more precise use of concepts associated with habitat fragmentation from the primates' perspective. When specific knowledge of the study species/population is available, we suggest that the definition of the variables to be measured should be functional from the primates' perspective, based, e.g., on their habitat requirements and dispersal capacity. The distance to the nearest fragment may not be the best way to measure the isolation between populations. Fragmentation per se is a landscape scale process and, hence, landscape scale studies are required to understand how species are distributed across heterogeneous landscapes. Finally, it is important to consider that what happens at the fragment scale could be the consequence of processes that interact at various spatial and temporal scales.

The populations of the Mexican mantled howler monkey (Alouatta palliata mexicana) in the Los Tuxtlas region, Mexico, have declined drastically due to habitat loss and fragmentation. Nevertheless, several troops still inhabit very small and isolated rain forest fragments. We identified the main vegetation attributes that can favor the presence of howlers within 18 small (< 10-ha) fragments that did not differ significantly in size, shape, and isolation (nine occupied and nine unoccupied by howlers). We found that habitat quality (i.e., food resources and vegetation structure) affected howler incidence in small fragments. Particularly, the occupied fragments showed greater density of big trees (dbh > 60 cm), greater total basal area, greater basal area of persistent tree species, and greater basal area of top food species than the unoccupied fragments; suggesting that even for small fragments the loss of big trees and particularly the decrease in size class of the top food species can negatively affect howler distribution in highly fragmented landscapes. These findings could be used to establish foreground conservation areas for this critically endangered subspecies in fragmented landscapes of Los Tuxtlas.Abstract in Spanish is available at http://www.blackwell-synergy.com/loi/btp.

Of what value are forest fragments to the conservation of the tropical rain forest diversity for a landscape? We compared the changes in composition, diversity, and plant structure of 15 small (1-76 ha) relatively unprotected forest fragments with those of a large (700 ha) well protected fragment (LWPF) in Los Tuxtlas, Mexico. The trees, shrubs, lianas, palms, and herbs with dbh ‡ 2.5 cm were sampled in 1000 m 2 at each site. For each ecological group (based on light requirements for germination: primary, secondary, and non-secondary light demanding, NSLD, species) and life form, estimates of species diversity, density, and basal area were analyzed using a stepwise multiple regression to determine whether there were any relationships between these variables and fragment characteristics (size, shape index, and isolation). The composition and plant structure of LWPF were different from those of the small fragments and large trees are absent from the canopy of the latter. Fragment size best explained the differences in composition and plant structure. Species composition in the largest fragments was similar to that of LWPF, but there was no significant difference in total richness between LWPF and the fragments, even though both the richness and abundance of secondary and NSLD species did differ. LWPF had more large primary trees in the canopy, and a greater abundance and basal area of palms and herbs. For tropical rain forest conservation, it is important to maintain the greatest possible number of large fragments and establish policies that prevent forest remnants from being further reduced in size and increasingly isolated from each other.

The diversity and organization of the mammalian community is related to the vegetation structure of the coffee plantations in the area of Barranca Grande, in the State of Veracruz, Mexico. Four transects (each 200 m in length) were used to study the vegetation structure within the coffee plantation, and 178 night/traps, tracks registration and information from local people, were used in order to become familiar with the mammalian community. The sample period was from October 1989 to February 1991. The 24 mammals of medium-size species present in the area were classified using two measures of ecological diversity, locomotion and foraging in order to understand the guild organization. If the complexity of the plantation is reduced, the number of guilds occupied could suffer a loss of 45% and 43% in ecological richness and diversity, respectively, and 24% in the equitability of the mammalian fauna. We recommend the maintenance of a high diversity in the tree stratum (shade species), in this case, species such as Inga jinicuil, banana (Musa sapientum), Citrus spp., coyo avocado (Persea schiedeana), mango (Mangifera indica); species which could provide food resources and protection for the mammals.Resumen. En el ~irea de Barranca Grande, Estado de Veracruz, M6xico, se estudi6 la relaci6n que tiene la estructura de la vegetaci6n de los cultivos de caf6 con la diversidad de la comunidad de mamiferos medianos. Para ello, se establecieron 4 transectos fijos de 200 m de largo cada uno, en los que se tomaron los datos de los diferentes estratos. Para conocer la fauna de mamiferos, se hizo un muestreo con trampas Tomahawk (178 noches/trampas), registro de rastros asi como encuestas a la gente que vive en la zona, entre Octubre de 1989 y Febrero de 1991. Se registraron 24 especies de mamiferos medianos que fueron clasificados utilizando dos medidas de diversidad ecol6gica, locomoci6n y forrajeo, para conocer la organizaci6n en gremios. Si se reduce la complejidad de los cafetales, puede existir una reducci6n hasta del 45% en el n~mero de gremios ocupados, 43% en la riqueza y en la diversidad ecol6gica, y 24% en la equitatividad. Se recomienda mantener una alta diversidad en el estrato arb6reo, en este caso especies como el jinicuil (lnga finicuil), plfitanos (Musa sapientum), citricos (Citrus spp.), pagua o aguacate (Persea schiedeana), mango (Mangifera indica), serian recomendables ya que proporcionan recursos alimenticios y protecci6n a la mayoria de los mamiferos.

Understanding how forest cover is related to patch attributes such as size, shape, and isolation, and how this influences the occurrence of a species in fragmented landscapes is an important question in landscape ecology and conservation biology. To study the effects of fragmentation on patch occupancy by the critically endangered Mexican mantled howler monkey (Alouatta palliata mexicana) in the Los Tuxtlas region of Mexico, we selected three landscapes of ca. 5,000 ha, which differed in their remaining forest cover (24, 11, and 4%). For each landscape, we related patch occupancy to forest cover, patch size and shape, and four isolation parameters. Landscape attributes varied according to forest cover, and the percentage of occupation was greater in landscapes with more forest cover. The attributes affecting the probability of occupancy differed among landscapes. Occupancy was positively related to patch size in all landscapes, but in the northernmost landscape, shape irregularity had a negative effect on occupancy, whereas in the southernmost landscape, occupancy was favored by greater distances to the nearest village. The results show that not only the total amount of forest cover but also patch configuration need to be taken into consideration when designing management strategies for the conservation of the Mexican mantled howler monkey.