Climate change is implicated as a leading cause of insect declines. One way that insects respond to the warming climate is by advancing phenology and increasing voltinism (adding generations). However, if earlier phenology changes cue-response relationships, then late season generations might lack time or resources to complete development before winter and insects attempt doomed “lost generations”. Using 27 years of monitoring of 30 butterfly species, we find the opposite, as added generations increase population growth rates of multivoltine butterflies. We find lost generations are rare and occur at cooler sites in years with cold winters or early frosts. Overall, long-term population trends are positively correlated with increasing voltinism over time, suggesting additional generations as one mechanism by which species adapt to the changing climate. Long-term monitoring programs can test mechanistic hypotheses about biotic responses to warming while simultaneously tracking if population consequences match the predicted outcomes.

Recent international agreements have strengthened and expanded commitments to protect and restore native habitats. Nevertheless, biodiversity conservation is hindered because how such commitments should be implemented has been strongly debated. By bringing together researchers on both sides of the habitat fragmentation debate, we identify three incontrovertible principles for area-based biodiversity conservation. Such principles are related to habitat geographic coverage, amount, and connectivity. They emerge from our fundamental agreement that, while large areas of nature are important and must be protected, conservation or restoration of multiple small habitat patches is also critical for global conservation, particularly in regions with high land use. We contend that the many area-based conservation initiatives expected in the coming decades should follow the principles we propose. Considering the importance of biodiversity for maintenance of ecosystem services, we suggest that this would bring unequivocal societal benefits.

Recent agreements have strengthened and expanded ongoing international commitments to protect and restore native habitats. Nevertheless, how such commitments should be implemented has been historically controversial, and nuances in ongoing debates are often misunderstood, hindering biodiversity conservation. We propose three unequivocal principles that must be central to how area-based biodiversity conservation will occur in the coming decades. These principles relate to habitat coverage, amount, and connectivity, and their enunciation clarifies apparent contradictions in the literature. We explain why socio-economic considerations that are central to current biodiversity conservation cannot override these principles. Biodiversity must be supported everywhere on Earth, especially when considering the right of human population to access nature and to benefit from countless ecosystem services.

Long-term experiments are important in evaluating ecosystem properties and processes that are slow to develop or require proper evaluation over an appropriately variable climate. We repurpose the wealth of data accessible through the forty-year-old Long-Term Ecological Research (LTER) network with a novel moving window algorithm and meta-analysis approach to ask if aspects of study taxa or environment alter the extent of research necessary to detect consistent results, or the proportion of spurious short-term trends. We found that experimental studies focused on plants, and those conducted in dynamic abiotic environments, were characterized by longer critical temporal thresholds and more spurious trends. Further, nearly half of the studies we investigated required 10 years or longer to reach a temporal threshold, and 4 studies (of 100) required longer than 20 years. We champion long-term data and argue that long-term experiments are more necessary than ever to understand, explain, and predict long-term trends.