Humans have elevated global extinction rates and thus lowered global scale species richness. However, there is no a priori reason to expect that losses of global species richness should always, or even often, trickle down to losses of species richness at regional and local scales, even though this relationship is often assumed. Here, we show that scale can modulate our estimates of species richness change through time in the face of anthropogenic pressures, but not in a unidirectional way. Instead, the magnitude of species richness change through time can increase, decrease, reverse, or be unimodal across spatial scales. Using several case studies, we show different forms of scale‐dependent richness change through time in the face of anthropogenic pressures. For example, Central American corals show a homogenization pattern, where small scale richness is largely unchanged through time, while larger scale richness change is highly negative. Alternatively, birds in North America showed a differentiation effect, where species richness was again largely unchanged through time at small scales, but was more positive at larger scales. Finally, we collated data from a heterogeneous set of studies of different taxa measured through time from sites ranging from small plots to entire continents, and found highly variable patterns that nevertheless imply complex scale‐dependence in several taxa. In summary, understanding how biodiversity is changing in the Anthropocene requires an explicit recognition of the influence of spatial scale, and we conclude with some recommendations for how to better incorporate scale into our estimates of change.

protected areas (pAs) are a foundational and essential strategy for reducing biodiversity loss. However, many pAs around the world exist on paper only; thus, while logging and habitat conversion may be banned in these areas, illegal activities often continue to cause alarming habitat destruction. in such cases, the presence of armed conflict may ultimately prevent incursions to a greater extent than the absence of conflict. Although there are several reports of habitat destruction following cessation of conflict, there has never been a systematic and quantitative "before-and-after-conflict" analysis of a large sample of pAs and surrounding areas. Here we report the results of such a study in colombia, using an open-access global forest change dataset. By analysing 39 PAs over three years before and after colombia's peace agreement with the Revolutionary Armed forces of colombia (fARc), we found a dramatic and highly significant increase in the deforestation rate for the majority of these areas and their buffer zones. We discuss the reasons behind such findings from the Colombian case, and debate some general conservation lessons applicable to other countries undergoing post-conflict transitions. The growing warfare ecology literature reports both negative and positive effects of conflict for biodiversity and the natural environment 1-3. This also applies to deforestation, which can be either increased or decreased depending on the specific complex socio-ecological dynamics linked to the conflict itself 3-5. Increased deforestation during conflict is reported for several regions of the world 6 , including Democratic Republic of Congo (DRC) and Liberia 7 or Myanmar and Cambodia 8. In some cases, conflict reduces the institutional capacity to enforce laws and effectively manage the use or protection of natural resources, e.g. as reported for Kenya 9 , DRC 10 , Nepal 11 , and Colombia 5. In other cases, the displacement of people escaping or forced to leave conflict areas, the basic mechanism for the 'refuge effect' 12 , can prove beneficial for habitat and biodiversity protection, e.g. by limiting the pressure of resource extraction 13-15. The demilitarized Zone between North and South Korea is a good example of such a refuge 16. Conflict can largely disrupt economic activities 1 , such as timber logging in Nicaragua 17 , or farming, as in Sierra Leone 18. In the Chechen wars and in the nearby Nagorno-Karabakh conflict, agricultural land was abandoned in warzones, along with reported low re-cultivation rates after the cessation of the conflict 19,20. In other cases post-conflict development results in higher threats to forested ecosystems than conflict

Noise can cause marine mammals to interrupt their feeding, alter their vocalizations, or leave important habitat, among other behavioural responses. The current North American paradigm for regulating activities that may result in behavioural responses identifies received levels (RL) of sound at which individuals are predicted to display significant behavioural responses (often termed harassment). The recurrent conclusion about the need for considering context of exposure, in addition to RL, when assessing probability and severity of behavioural responses led us to conduct a systematic literature review (370 papers) and analysis (79 studies, 195 data cases). The review summarized the critical and complex role of context of exposure. The analysis emphasized that behavioural responses in cetaceans (measured via a linear severity scale) were best explained by the interaction between sound source type (continuous, sonar, or seismic/explosion) and functional hearing group (a proxy for hearing capabilities). Importantly, more severe behavioural responses were not consistently associated with higher RL and vice versa. This indicates that monitoring and regulation of acoustic effects from activities on cetacean behaviour should not exclusively rely upon generic multispecies RL thresholds. We recommend replacing the behavioural response severity score with a response/no response dichotomous approach that can represent a measure of impact in terms of habitat loss and degradation.

Vessel collision is a threat to many whale species, and the risk has increased with expanding maritime traffic. This compromises international conservation efforts and requires urgent attention from the world's maritime industry. Humpback whales (Megaptera novaeangliae) are at the top of the death toll, and although Central America is a wintering area for populations from both the Northern and Southern Hemispheres, existing efforts to reduce ship‐whale collisions are meager. Herein, we evaluated the potential collisions between vessels and humpback whales wintering off Pacific Panama by following the movements of 15 whales tagged with satellite transmitters and comparing these data with tracks plotted using AIS real‐time latitude‐longitude points from nearly 1,000 commercial vessels. Movements of whales (adults and calves) in the Gulf of Panama coincide with major commercial maritime routes. AIS vessel data analyzed for individual whale satellite tracks showed that 53% (8 whales) of whales had 98 encounters within 200 m with 81 different vessels in just 11 d. We suggest implementing a 65 nmi Traffic Separation Scheme and a 10 kn maximum speed for vessel routing into the Gulf of Panama during the wintering season. In so doing, the area for potential whale‐vessel collisions could be reduced by 93%.

Octocorals (order Alcyonacea) from the tropical eastern Pacific have been largely ignored in coral reef studies, with the exception of recent taxonomic reviews. This study is the first to examine the population dynamics of 10 shallow water species in six genera (Leptogorgia, Pacifigorgia, Muricea, Psammogorgia, Heterogorgia, and Carijoa) found in rocky coral communities in Coiba National Park, Pacific Panama. For a 17-mo period, we monitored, every 4 mo, 1445 colonies of 15 species in fixed plots at 20 m depth in four coral communities. Size distribution, survivorship, and recruitment rates were calculated. Growth rate was calculated for Leptogorgia alba Duchassaing and Michelotti, 1864, Pacifigorgia Irene Bayer, 1951, Psammogorgia arbuscula Verrill, 1868, and Muricea austera Lamouroux, 1821. Average octocoral density was 38.7 (SD 27.55) colonies m −2 (n = 1394) with a range of 1-103 colonies m −2 and 1-11 species within a study plot. An overall population decline of 25.2% was observed in 1 yr. Leptogorgia alba was the most common species; it was abundant at all sites and exhibited characteristics of an r-selected species. In contrast, M. austera showed traits of a K-selected species, with low mortality and recruitment rates. Studied species were grouped into two distinct clusters based on their distribution, average density, mortality, and recruitment rates. Five species were grouped with L. alba and six species were grouped with M. austera.