Search

Mistletoes are hemiparasitic plants and keystone species in many ecosystems globally. Given predicted increases in drought frequency and intensity, mistletoes may be crucial for moderating drought impacts on community structure. Dependent on host vascular flows, mistletoes can succumb to stress when water availability falls, making them susceptible to mortality during drought. We counted mistletoe across greater than 350 000 km 2 of southeastern Australia and conducted standardized bird surveys between 2016 and 2021, spanning a major drought event in 2018–2019. We aimed to identify predictors of mistletoe abundance and mortality and determine whether mistletoes might moderate drought impacts on woodland birds. Live mistletoe abundance varied with tree species composition, land use and presence of mistletoebirds. Mistletoe mortality was widespread, consistent with high 2018/2019 summer temperatures, low 2019/2020 summer rainfall and the interaction between summer temperatures and rainfall in 2019/2020. The positive association between surviving mistletoes and woodland birds was greatest in the peak drought breeding seasons of 2018/2019 and 2019/2020, particularly for small residents and insectivores. Paradoxically, mistletoes could moderate drought impacts on birds, but are themselves vulnerable to drought-induced mortality. An improved understanding of the drivers and dynamics of mistletoe mortality is needed to address potential cascading trophic impacts associated with mistletoe die-off.

In the public at large, property and contract law are commonly thought to reflect moral proprietary and promissory rights. Contemporary philosophers are mostly sceptical about natural property rights, though not about promissory rights. I argue at length that contract and promise, no less than property, can only be justified instrumentally – by appeal to the social good that these conventional practices produce. The aims of these practices need not be limited to social welfare but can include social justice and values more closely connected to the subject matter of the practices. The illusion that the law of the market reflects individual natural rights is harmful to public political discourse about institutional design. For example, it leads to ungrounded ideas about a right to freedom of contract and severely distorts the discussion of tax policy. The tenaciousness of this illusion deserves investigation. Promise and property are backed up and enforced by contract and property law. These legal orders necessarily take the form of a set of rules that specify legal rights and obligations. Living our lives in a social world structured in significant part by the law of the market, it is very hard to see those legal rights and obligations as not reflecting a deontological order of moral rights and obligations. We have here a case where misunderstanding the formation of legal normative orders leads us astray in our understanding of moral normative orders. This in turn hinders us in our ability to see clearly what the options for morally sound reform of the legal normative orders may be.

This paper argues that the disagreement between positivists and nonpositivists about law is substantive rather than merely verbal, but that the depth and persistence of the disagreement about law, ...