Two globally threatened tree species, the Critically Endangered Cola porphyrantha (Malvaceae) and the Endangered Gigasiphon macrosiphon (Fabaceae) are narrowly distributed in Kenya and Tanzania. In Tanzania, both species were first located in an isolated, unprotected forest fragment in the East Usambara Mountains in the early 2000s. As no assessment of these subpopulations had been made since then, we surveyed the forest fragment as well as nearby unprotected forest fragments. In contrast to the early 2000s when only five and two mature trees of C. porphyrantha and G. macrosiphon, respectively, were located, we found 18 and five mature trees of these species. We did not find either species in intensive surveys of seven neighbouring unprotected forest fragments but we located a single G. macrosiphon beside a river close to one of the unprotected fragments. Gigasiphon macrosiphon was also previously known from two sites in Amani Nature Reserve in the East Usambara Mountains, but recent surveys, including our own, failed to relocate these subpopulations. Because of heavy anthropogenic disturbance in the one site where the two species still occur and their general absence from adjacent forest, we are working with the local community to protect the isolated fragment. Additionally, in situ planting of locally grown seedlings of both species is being supported by Amani Nature Reserve.

Traditionally the vulnerability of threatened species to extinction has been assessed by studying their environment, genetics and population dynamics. A more comprehensive understanding of the factors promoting or limiting the long-term persistence of threatened species could be achieved by conducting an analysis of their functional responses to changing environments, their ecological interactions, and their role in ecosystem functioning. These less traditional research areas can be unified in a trait-based approach, a recent methodological advance in ecology that is being used to link individual-level functions to species, community and ecosystem processes to provide mechanistic explanations of observed patterns, particularly in changing environments. We illustrate how trait-based information can be translated into well-defined conservation strategies, using the example of Dioon sonorense, an Endangered cycad endemic to north-western Mexico. Scientific information yielded by trait-based research, coupled with existing knowledge derived from well-established traditional approaches, could facilitate the development of more integrative conservation strategies to promote the long-term persistence of individual threatened species. A comprehensive database of functional traits of threatened species would be of value in assisting the implementation of the trait-based approach.

Fuscopannaria leucosticta is a rare and understudied cyanolichen with an interesting and unusual distribution in tertiary relict hotspots worldwide. There is a relatively large population in eastern North America, where it occurs mostly throughout the Appalachian Mountains and reaches its northernmost extent in New Brunswick and Nova Scotia, Canada. The ability to detect this species, and thus determine its habitat requirements, is critical for understanding how it might be affected by human-induced environmental degradation. Maximum entropy modelling with MaxEnt was used to predict the distribution of suitable habitat for this species in Nova Scotia using 62 presence locations, 1405 pseudo-absence locations and four environmental covariates: depth to water table (a proxy for relative soil moisture), distance to the coast and mean annual temperature and precipitation. Our predictive maps identify important habitat features and areas of high suitability in Nova Scotia with an area under the curve value of 0·85. The predicted distribution of this lichen was most affected by temperature. This study elucidates locations as well as species-habitat relationships for F. leucosticta, providing land managers with baseline data that can aid in the discovery of additional populations and provide a better understanding of its ecological requirements which will support the development of sound conservation strategies for this rare lichen.

The bush dog Speothos venaticus is a medium-sized Neotropical canid. It is considered to be rare and its biology and population parameters are still poorly understood. The Amazon is one of the main strongholds of this species and is important for maintaining viable populations, as the region still holds extensive tracts of pristine habitat. We gathered field data from camera-trap studies throughout the Brazilian Amazon to estimate the relative abundance of the species and gain an understanding of its rarity, and how this compares with estimates from other vegetative formations and for sympatric hypercarnivores. We focused on three pristine or partially disturbed sites and one fragmented site. The estimated relative abundance of the species was 0.060–0.185 individuals per 100 trap-days, confirming that the species is rare. The bush dog's abundance in the Amazon is equivalent to that in all other areas outside the Basin. The mean group size recorded was c. 2.5 individuals. There were no differences in group sizes between forests in the Amazon and in other regions of Central America; however, there were significant differences between forests and open habitats. A combination of competition/predation, habitat structure/integrity, and disease may be acting synergistically in determining the abundance and rarity of bush dogs.

Forest loss has caused fragmentation and destruction of habitats, and thereby presents serious extinction risk to many endemic species in Madagascar. Among many other arthropod groups, carabid beetles are poorly known in Madagascar as regards their distribution, habitat requirements and taxonomy. The aim of this study is to document community composition, distribution patterns and habitat preferences of carabids in the forest-dominated Ranomafana National Park, south-eastern Madagascar. Carabids were collected by hand and trunk traps from secondary forest, primary forest and nearby village areas. In total, 4314 individuals representing 125 species, including 38 new species, were collected. Almost 70% of the species were recorded in very low abundances. Furthermore, there were only a few species in intermediate abundance classes, while the three most abundant species represented ~36% of the total catch. The carabid community seems to be very species rich, consisting mostly of species in low abundances. A positive correlation was found between abundance and occupancy despite high variation among species distribution patterns. Small population sizes of endemic species with nearby habitat destruction make the species especially vulnerable to extinction and increase the importance of protecting Ranomafana National Park.

The conversion of grasslands for agriculture has triggered a serious decline of the European ground squirrel or souslik Spermophilus citellus, categorized as Vulnerable on the IUCN Red List since 1996. The Jakupica phylogeographic lineage of central Macedonia is the smallest of the three major evolutionary lines of the European souslik. This lineage is an important reservoir of within-species diversity and should be regarded as an independent unit for conservation management purposes. It is endemic to Mount Jakupica, where it lives in mountain pastures at 1,500–2,250 m altitude. The total area occupied by sousliks (884 ha) is fragmented and 94% of individuals occur in four colonies. Densities (0.8–5.5 adults ha−1) are lower than those reported elsewhere for the species, with the total population probably <2,000 adults. One large colony, reportedly of c. 1,000 sousliks, was decimated in 2007 by a catastrophic fire and had still not recovered by 2010. A steady decline in livestock grazing, together with the predicted advance of the tree line as a consequence of climate change, will probably reduce the optimal habitat for the souslik and negatively affect population fitness. Monitoring needs to be implemented, at least for the largest colonies, to provide early warning of any declines.

Assessments of conservation status are usually carried out on a global scale but national priorities often necessitate a more focused approach. Using a typology of rarity first articulated in the early 1980s by Deborah Rabinowitz, coupled with presence/absence from protected areas, preliminary conservation status at the national level was assessed for 397 species of ferns and fern allies from El Salvador in Central America. Of these, 43 lacked sufficient data, 175 were considered not of conservation concern, 106 were considered to be at risk and 73 to be threatened. The majority of the threatened species were from cloud or montane forest habitats but aquatics and species restricted to pine–oak forests are also rare and occur outside protected areas. The utility of this simple methodology is discussed and the importance of field studies by local experts with local knowledge emphasized.

A 100-ha quadrat of primary rainforest in French Guiana was ccnsused over two consecutive years by the mapping method, and a 24-ha core area was intensively mistnetted at the same time. More extensive surveys were conducted in successively larger areas including up to a large part of the forested interior of the country. From a total of 441 resident species found in the rainforest zone, 248 were regularly recorded within the 100-ha plot, 157 of which had mean densities of more than 1 pair km-2. The total estimated density of birds was at least 829 pairs km-2. Only two dominant species exceeded 20 pairs km-2, while 52% of all the species were represented by less than 2 pairs km-2. The distribution of body masses and niche characteristics among the bird community is given as well as the sample bias of the mistnet captures.

Rare species were a key component of this primary rainforest community. Several patterns of rarity were described and no marked and constant relationships were found between rarity and body size, habitat, diet, foraging behaviour or social system. Among a wide set of environmental constraints, the population of each species may be limited by a different combination of factors. Habitat heterogeneity, low, irregular and seasonal food availability, interspecific competition or heavy predation pressure were prominent and likely causes of the low density of most species which in turn facilitated the high species richness.

The long-term dynamics of epiphyte communities are little studied although such baseline data are urgently needed, in particular in the context of global change. Census data of a vascular epiphyte community from 0.4 ha of undisturbed lowland forest in Panama were used to infer future changes in community composition by deducing population growth from the current size class structure of populations. The study includes 11 387 individuals out of 45 species, ranging in abundance from 16 to 1568 individuals. There was a significant negative correlation between the size of a population and the steepness of the size distribution, indicating that more common species are likely to increase in abundance in the future, while rarer species apparently depend on immigration from other populations to allow local persistence.

Lianas of Yasuní National Park and the Huaorani Ethnic Reserve, Ecuador were sampled using 0.2-ha subsamples from 12 1-ha plots. Using surveys and herbarium collections, the total species richness of lianas in the park and reserve is estimated to be close to 500 species. Terra firme habitats are significantly more species rich than floodplain habitats, but density of stems is not significantly different between habitats. The most abundant liana species is Machaerium cuspidatum Kuhlm. & Hoehne (Fabaceae) in both floodplain and terra firme habitats, representing more than 10% of all stems in census plots. Analysis of rarity indicates that none of the liana species encountered on the 12 plots is rare in terms of geographic range, and many species are not rare in terms of population size or habitat specificity. The rank order of abundance, combined with the coefficient of variability in species distribution among plots, is used to identify the 38 species (an oligarchy) that dominate forests in Yasuní.

Distribution patterns of vascular plants with diameter at breast height (dbh) ≥ 2.5 cm were studied on the basis of compositional data from 30 small plots located in a rain-forest area in Colombian Amazonia. The research questions were: How are distribution patterns of species in relation to local abundance in plots? Do understorey species (defined as species with individuals that never attained dbh ≥ 10 cm anywhere) show better correlations with soils and environment than canopy species (defined as species with individuals that attained dbh ≥ 10 cm)? Are patterns found in the entire range of landscape units comparable to those found in well-drained uplands alone? Species that occurred in more than one plot showed higher local abundances. This pattern was consistent among environmental generalists and specialists. Locally rare species (with only one individual in a plot) occurred mostly in well-drained uplands. Considering all landscape units, Mantel tests showed substantial correlations between environmental data (soil chemical data, drainage and flooding) and species composition. Canopy species were only slightly less correlated with environmental data than understorey species. Elimination of the spatial component in the data did not reduce these correlations. In well-drained uplands, understorey species were better correlated with soils than canopy species. Here, however, the spatial configuration of the plots became more important in explaining species patterns.

This study is the first to compare bird communities across different sites within the same large continuous neotropical primary forest area. The objectives were to document bird distribution patterns, the spatial variability of specific abundances and the between-site turnover in species compositions. I censused 268 forest-interior species, 39 raptors and 135 natural-gap species in 20 widely spaced, c. 2000-ha sites in the interior of French Guiana, divided into three main zones. At least 59% of species had a very low abundance index and/or rate of occurrence among sites and only 1% were widespread dominants. Beta diversity was an important determinant of regional species richness. There was an average 29% species turnover between sites and 7% between regions, as well as a lack of nested-subset structure among communities and a random occurrence of pairs of similar congeners. At the country scale, only one species had a truly restricted geographical range, independent of habitat availability, but at a local scale, many species had uneven distributional gaps (36% present at < 50% of sites with suitable habitat). Among sites, abundance or incidence variability had no definite pattern. Frequency of occurrence in suitable patches decreased with increasing natural fragmentation of habitats. There were significant relationships between habitat selection and abundance or frequency of occurrence but not with diet or body size. Few species exhibited consistent geographical trends along the north-south gradient of decreasing rainfall. Guianan endemics tended to be widespread within the country. Several seasonal movements and inter-annual population fluctuations were documented. Rarity had different forms, but no general ecological correlates. Nearly half of rare species were associated with various types of forest gaps or edges, and were consequently more abundant outside the forest zone, i.e. in grasslands or clearings. Local occurrences and abundances seem to be the result of highly species-specific factors, and hence any general determinant of community structure may be obscured by specific reactions in such species-rich, heterogeneous and complex tropical rain-forest communities.

Breeding systems and dispersal mechanisms of plants (≥ 2.5 cm dbh) were examined in fragments of tropical dry forest in Central America to identify life-history characteristics associated with rarity. In particular, the richness and abundance of dioecious and mammal-dispersed trees and shrubs were examined to identify potential associations with precipitation, anthropogenic disturbance, and area. Plots totalling 1000 m2 per site were established in seven nature reserves in Costa Rica (two sites) and Nicaragua (five sites). Overall, tropical dry forests of Central America have a similar proportion of dioecious species to other lowland neotropical forests and a similar proportion of wind-dispersed plants to other tropical dry forests around the world. However, the number of dioecious and mammal-dispersed species declined with decreasing forest cover within each reserve. Although dioecious species were rare in smaller forest fragments, some of these species will not be threatened with regional extinction because they are early successional plants, they have large geographic ranges, and they are not restricted to the tropical dry forest life zone. Mammal-dispersed plants were rare in small fragments, but it is not clear whether this was due to the loss of dispersal vectors or other life-history characteristics.

The reproductive phenology of a population of 39 adult trees of Couratari multiflora was studied in ‘terra firme' forests located 90 km N of Manaus, Amazonas, Brazil. Trees of this species, found in low densities, were inventoried in a 400-ha plot in which only one tree ≥ 20 cm DBH per 10 ha was encountered. This species flowers from January to June, with a peak in the mid-wet season (March), and fruits during the dry season (May-September). Median distances between synchronized flowering trees were 600 to 1000 m depending on the time of the flowering season. The number of synchronous flowering trees at each observation date in the 400-ha plot was 14 or 17.5 per 1 d, 13 (both) per 15 d, and three or 13 per 30 d, depending upon which of the two methods was used to evaluate synchrony. Fifty percent of the flowering trees overlapped in flowering with six to seven other flowering trees growing within a radius of 1000 m during most of the annual flowering period. Outcrossing rates were 100 % and the relatively long distances between trees in flower at the same time, support the assumption that this species is pollinated by pollinators travelling distances as far as 1000 m.