To address the challenges of biodiversity conservation and commodity production, a framework has been proposed that distinguishes between the integration (“land sharing”) and separation (“land sparing”) of conservation and production. Controversy has arisen around this framework partly because many scholars have focused specifically on food production rather than more encompassing notions such as land scarcity or food security. Controversy further surrounds the practical value of partial trade‐off analyses, the ways in which biodiversity should be quantified, and a series of scale effects that are not readily accounted for. We see key priorities for the future in (1) addressing these issues when using the existing framework, and (2) developing alternative, holistic ways to conceptualise challenges related to food, biodiversity, and land scarcity.

Land sparing versus land sharing: Moving forward

Dispersal is a crucial process for species persistence under natural and disturbed landscapes. The effectiveness of stepping stones as a connectivity strategy for increasing dispersal success depends on landscape structure and animal behaviour, such as the perceptual range. We quantify the relative contribution of stepping stones (small fragments and scattered trees) to dispersal success considering interactions with perceptual range, habitat amount and configuration. We develop an individual-based model (IBM) to simulate the dispersal movement of small mammals. The model is parametrized using empirical estimates of perceptual range and movement properties (turning angles and steps length). Simulations are implemented in landscapes with varying gradients of habitat amount and clumpiness, with and without the presence of stepping stones. Small patches and scattered trees combined, or only scattered trees, have a positive effect on dispersal. Meanwhile, the presence of only small patches has negative effects on dispersal. Habitat amount positively influences dispersal, which decreases abruptly when the habitat amount is less than 20%. This threshold disappears in the presence of stepping stones. In landscapes with intermediate levels of habitat amount, landscape fragmentation (low clumpiness) has a positive effect on dispersal success. Stepping stones, especially scattered trees, are a fundamental connectivity strategy for the conservation of small non-flying vertebrates in human-modified landscapes, particularly landscapes with less than 20% of habitat amount. However, small patches stepping stones may act as ecological traps leading the individuals to dead-ends. Their effectiveness in improving dispersal depends on both landscape structure and perceptual range.

Dispersal movement through fragmented landscapes: the role of stepping stones and perceptual range

Isolated trees support lower bird taxonomic richness than trees within habitat patches but similar functional diversity

ABSTRACT Neotropical manakins exhibit polygynous lekking systems in which males do not provide paternal care and exhibit elaborate courtship displays. Despite familial patterns, some historical field observations suggested that the Helmeted Manakin (Antilophia galeata) has evolved territoriality rather than lekking and a socially monogamous mating system. Furthermore, the evidence so far does not allow a clear understanding of the role played by resources, such as nesting sites and male behaviour in shaping the mating system in this species. Our objectives were to verify whether territorial behaviour occurs in the Helmeted Manakin and to provide a preliminary assessment of this species’ hypothesised social monogamy. Using an experimental approach with simulated territorial intrusions, we demonstrated that males in this species hold individual territories with nesting sites but do not provide parental care, similar to its congener, the Araripe Manakin (Antilophia bokermanni). Males’ responses occurred more aggressively in central areas of territories. Larger home ranges encompassed the smaller defended territories and the male display consists of repeated circular flights within the territory. Our results indicate that the Helmeted Manakin has a polygamous mating system. However, we suggest the species is better classified within the continuum of a resource-defence exploded-lek mating system. The distinct environmental conditions in which the species evolved may have played a significant role in modifying its behaviour, resulting in patterns that deviate from the typical lekking system found among manakins. This study highlights the importance of investigating atypical manakins to further our understanding of alternative reproductive tactics among birds.

Mariana de‐Carvalho

Papers

Isolated trees support lower bird taxonomic richness than trees within habitat patches but similar functional diversity

Individual territoriality in lekking species: the case of the Helmeted Manakin

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