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Although satellite‐based variables have for long been expected to be key components to a unified and global biodiversity monitoring strategy, a definitive and agreed list of these variables still remains elusive. The growth of interest in biodiversity variables observable from space has been partly underpinned by the development of the essential biodiversity variable (EBV) framework by the Group on Earth Observations – Biodiversity Observation Network, which itself was guided by the process of identifying essential climate variables. This contribution aims to advance the development of a global biodiversity monitoring strategy by updating the previously published definition of EBV, providing a definition of satellite remote sensing (SRS) EBVs and introducing a set of principles that are believed to be necessary if ecologists and space agencies are to agree on a list of EBVs that can be routinely monitored from space. Progress toward the identification of SRS‐EBVs will require a clear understanding of what makes a biodiversity variable essential, as well as agreement on who the users of the SRS‐EBVs are. Technological and algorithmic developments are rapidly expanding the set of opportunities for SRS in monitoring biodiversity, and so the list of SRS‐EBVs is likely to evolve over time. This means that a clear and common platform for data providers, ecologists, environmental managers, policy makers and remote sensing experts to interact and share ideas needs to be identified to support long‐term coordinated actions., DSS, RS, DR and JP were financed by the EU BON project that is a Seventh Framework Programme funded by the European Union under Contract No. 308454.

Nearly 40 years after passage of the US Endangered Species Act, the prospects for listed species remain dim because they are too severely imperiled by the time they receive the act’s protection. Even if threats are abated, the low abundances required for recovery often preclude a high probability of persistence. The lack of sufficient data for setting recovery objectives also remains a barrier. Delisting is considered possible for only 74% of the 1173 species with recovery plans—92% of threatened and 69% of endangered species. The median number of populations required for delisting (8) was at or below the historical numbers for 64% and at or below the numbers at listing for 37% of the species. The median number of individuals required for recovery (2400) exceeded the abundances at listing for 93% of the species, but most were below the levels considered necessary for long-term persistence, especially in changing environments.

Species listed under the U.S. Endangered Species Act (i.e., listed species) have declined to the point that the probability of their extinction is high. The decline of these species, however, may manifest itself in different ways, including reductions in geographic range, number of populations, or overall abundance. Understanding the pattern of decline can help managers assess extinction probability and define recovery ob- jectives. Although quantitative data on changes in geographic range, number of populations, and abundance usually do not exist for listed species, more often qualitative data can be obtained. We used qualitative data in recovery plans for federally listed species to determine whether each listed species declined in range size, num- ber of populations, or abundance relative to historical levels. We calculated the proportion of listed species in each state (or equivalent) that declined in each of those ways. Nearly all listed species declined in abundance, and range size or number of populations declined in approximately 80% of species for which those data were available. Patterns of decline, however, differed taxonomically and geographically. Declines in range were more common among vertebrates than plants, whereas population extirpations were more common among plants. Invertebrates had high incidence of range and population declines. Narrowly distributed plants and invertebrates may be subject to acute threats that may result in population extirpations, whereas vertebrates may be affected by chronic threats that reduce the extent and size of populations. Additionally, in the eastern United States and U.S. coastal areas, where the level of land conversion is high, a greater percentage of species' ranges declined and more populations were extirpated than in other areas. Species in the Southwest, especially plants, had fewer range and population declines than other areas. Such relations may help in the selection of species' recovery criteria.

Habitat loss and fragmentation are the major causes of biodiversity loss, and, increasingly, habitat is fragmented by urbanization. Yet, the degree to which urbanization creates barriers to animal dispersal remains poorly understood. We used population genetic techniques to determine whether urbanization and/or natural landscape features are dispersal barriers to a butterfly, Atrytonopsis new species 1, throughout its range on coastal sand dunes that are increasingly threatened by development. Using AFLP markers that produced 89 polymorphic loci, we found significant population structure across the range of Atrytonopsis sp1. We found no indication that existing levels of urbanization were barriers to Atrytonopsis sp1 dispersal. Rather, two natural barriers, an ocean inlet and maritime forest, explained the genetic structure. Even in areas with long histories of urbanization, we found no significant isolation-by-distance relationship, and there was very low genetic differentiation between sampling locations. Consequently, conservation strategies for Atrytonopsis sp1, and potentially for other mobile insects that use open-structured habitats, should not focus explicitly on habitat corridors through urban areas, but rather should seek to preserve and restore as much habitat as possible across the butterfly’s range.

Habitat fragmentation is a major driver of biodiversity loss. Yet, the overall effects of fragmentation on biodiversity may be obscured by differences in responses among species. These opposing responses to fragmentation may be manifest in higher variability in species richness and abundance (termed hyperdynamism), and in predictable changes in community composition. We tested whether forest fragmentation causes long-term hyperdynamism in butterfly communities, a taxon that naturally displays large variations in species richness and community composition. Using a dataset from an experimentally fragmented landscape in the central Amazon that spanned 11 years, we evaluated the effect of fragmentation on changes in species richness and community composition through time. Overall, adjusted species richness (adjusted for survey duration) did not differ between fragmented forest and intact forest. However, spatial and temporal variation of adjusted species richness was significantly higher in fragmented forests relative to intact forest. This variation was associated with changes in butterfly community composition, specifically lower proportions of understory shade species and higher proportions of edge species in fragmented forest. Analysis of rarefied species richness, estimated using indices of butterfly abundance, showed no differences between fragmented and intact forest plots in spatial or temporal variation. These results do not contradict the results from adjusted species richness, but rather suggest that higher variability in butterfly adjusted species richness may be explained by changes in butterfly abundance. Combined, these results indicate that butterfly communities in fragmented tropical forests are more variable than in intact forest, and that the natural variability of butterflies was not a buffer against the effects of fragmentation on community dynamics. © 2010 Leidner et al.