Ironstone outcrop habitats harbour rare and endemic rupicolous plants. In southeast Brazil, they concentrate on mountaintops in the Iron Quadrangle (IQ), an intensively exploited iron ore reserve. To evaluate the current habitat availability of 32 plants endemic to canga (ironstone outcrops) and to support priority conservation areas and actions, we compared their functional connectivity in the IQ before (1960s) and after (2014) massive habitat loss to opencast mining. The Integral Index of Connectivity and associated metrics of habitat availability were used to evaluate present and past connectivity at a threshold distance of 500 m. The overall canga habitat loss up to 2014 was 50%. The historical configuration of 334 patches totalling 18 654 ha was already disconnected and the proportion of patches acting as relevant stepping stones was thus very low. Furthermore, in both the historical and current settings, the largest contribution to habitat availability came from ‘intrapatch connectivity’ (i.e., patch area), especially in the east sector. All the IQ canga endemics fall into the International Union for Conservation of Nature (IUCN) Critically Endangered category and require protection. The recommended strategy for their conservation is to protect large, preferably well-preserved ironstone patches. This measure will require finding the middle ground between economic development and conservation of natural heritage.

Estimates of roosting habitat availability and population size using unbiased sampling regimes are completely lacking for any bat species. The use of conspicuous and accessible roosts in the developing, rolled leaves of Heliconia and Calathea plants by Thyroptera tricolor (Spix's disc-winged bat) provided an ideal opportunity to address this need. To assess roost availability and population size, the number of occupied and unoccupied leaves and bats in known areas in an area of lowland rain forest in north-eastern Costa Rica were quantified in 1998–99. A high density of leaves was available on any given day (mean: 43 leaves ha−1), but the density of roost leaves was low (mean: 2.5 leaves ha−1), corresponding with a low occupancy rate of 5.7 or 12% based on different methods of estimation. Developing leaves were available for 8–16 h in the preferred size range of leaves used by T. tricolor, and a maximum of 28–60 h, depending on the plant species. Using closed-population mark–recapture models, the 5.69-ha study area supported 261 individuals over a 4-mo period in 1998, corresponding to a density of 43 bats ha−1. These results have important implications for the results of studies on bat community structure and rarity, and for the behaviour and ecology of T. tricolor.

This paper addresses the conservation status of the spectacled bear Tremarctos ornatus in the northern Andes (Venezuela, Colombia and Ecuador) by analysing the degree of range fragmentation and estimating habitat availability. From satellite images we constructed maps of remnant habitat blocks, consisting of Andean forest and páramo (high elevation shrublands and grassland) ecosystems. This information was overlain with a road map to determine potential isolation of populations, and a human accessibility model was used to estimate the core area of each block. This analysis revealed that the species' range is fragmented by landscape transformation and roads into 113 blocks >100 km2, representing 42% of the original extent of the bear's distribution. Forty percent of the blocks are <500 km2, and only nine are >5,000 km2. However, taking into account only core area, 56% of the blocks are <500 km2 and only six are >5,000 km2. In addition, many blocks have internal patches of colonization, further reducing habitat quality. This effect is more severe in smaller fragments, where internal disturbances constitute a high proportion of the block area. We used a high population density estimate of 0.25, a medium density of 0.11 and a low density of 0.04 bears per km2 to estimate population sizes. Twenty-nine populations are likely to have >500 individuals with the high estimate, but only nine with the medium and one with the low estimate (largest estimated population was 9,048 bears). These estimates are much lower if only the core area of blocks is used. Hunting has been identified as a major threat for many bear populations. Our analyses indicate that a regional conservation strategy for spectacled bear should focus on maintaining or increasing habitat availability in larger blocks, and reducing human-induced mortality across the region.