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Understanding the seasonal movements of migratory species underpins ecological studies. Nearly 600 butterfly species show migratory behaviour, yet the spatial pattern of these migrations is poorly understood. We developed climatic niche models for 405 migratory butterfly species globally to estimate patterns of seasonal movement and the distribution of seasonal habitat suitability. We discover strong seasonal variation in habitat suitability for most of the migratory butterflies with >75% of pixels showing seasonal change in predicted occupancy for 85% of species. In contrast to bird migrations, the greatest rate of seasonal switching occurs in the tropics. Several species showed extreme range fluctuations, exceeding 10-fold for 53 species (13%) and more than 100-fold for nine species (2%); such species may be at elevated extinction risk. Our results can be used to search for the ecological processes that underpin migration in insects, as well as to design conservation interventions for declining migratory insects.

Humanity is on a pathway of unsustainable loss of the natural systems upon which we, and all life, rely. To date, global efforts to achieve internationally-agreed goals to reduce carbon emissions, halt biodiversity loss, and retain essential ecosystem services, have been poorly integrated. However, these different goals all rely on preserving natural ecosystems. Here, we show how to unify these goals by empirically deriving spatially-explicit, quantitative area-based targets for the retention of natural terrestrial ecosystems. We found that at least 67 million km2 of Earth's natural terrestrial ecosystems (~79% of the area remaining) require retention, via a combination of strict protection but more prominently through sustainably managed land use regimes complemented by restoration actions, to contribute to biodiversity, climate, soil and freshwater objectives under four United Nations' Resolutions. This equates to retaining natural ecosystems across ~50% of the total terrestrial (excluding Antarctica) surface of Earth. Our results show where retention efforts could be focused to contribute to multiple goals simultaneously. The retention targets concept that we present explicitly recognises that such management can and should co-occur alongside and be driven by the people who live in and rely on places where natural and semi-natural ecosystems remain on Earth.

The impact of invasive species at seabird breeding islands causes a breakdown of important ecological functions such as prey consumption and nutrient transfer, and elevates extinction risk in impacted taxa. Eradicating invasive species from islands can result in substantial short-term recovery of seabird populations and consequently the prevalence of eradication programs as conservation tools is increasing. However, as the scale and complexity of eradications has increased, quantitative data on rates of recovery, especially from larger islands, remain limited. Furthermore, the mechanisms that govern recovery are poorly understood, limiting our ability to forecast outcomes and therefore prioritise effectively. Here, using the world's largest multi-species vertebrate eradication from Macquarie Island as a case study, we show how responses to invasive species and their eradication differ. Species with broad realised niches whose breeding phenology minimizes time on land and corresponds with summer resource abundance remained extant alongside invasive species while more habitat-specific species present in winter were extirpated. Following eradication, immigration and flexibility to colonise under-utilised optimal habitat appears to be boosting population growth in recolonising species, whereas established populations appear to be tethered to refugial habitats by the influence of philopatry, and their recovery is slower as a result. Unpicking these differential responses and the mechanisms behind them provides valuable information to help predict responses in other systems as future eradications are planned.

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