Sibling aggression, hatching asynchrony, and nestling mortality in the black kite (Milvus migrans)

In siblicidal species, hatching asynchrony could act to reduce sibling rivalry or promote the death of last-hatched chicks. The pattern of hatching asynchrony was experimentally altered in the black kite Milvus migrans. Hatching asynchrony in control broods was intermediate between those of experimentally synchronised and asynchronised broods. Sibling aggression and wounds on the chicks were more commonly observed early in the nestling period and in synchronous nests. Serious injuries were observed on last-hatched chicks in asynchronous nests, as were observations of intimidated or crushed chicks. Sibling aggression was related to food abundance, but some chicks died at an early age in nests with abundant food (cainism). Cainism was more commonly found in asynchronous nests. For species with facultative siblicide, moderate hatching asynchrony could be a compromise between reducing sibling rivalry and avoiding large size differences between sibs that would result in cainism. Female black kites preferentially fed the smallest chicks and exhibited behaviours to reduce sibling aggression, contrary to observations in other siblicidal species. In a highly opportunistic forager such as the black kite, a strategy may exist to protract the life of all the chicks in the brood, waiting for unpredictable situations of food overabundance. This would induce the appearance of a parent-offspring conflict over brood reduction, reflected in the existence of a possible anticipated response by some of the chicks (cainism) and in the appearance of special behaviours by the parents to selectively feed smaller chicks or reduce sibling aggression. In this facultatively siblicidal species, cainism does not seem to be the final stage of an evolutionary trend favouring the raising of high-quality chicks, but a manifestation of a parent-offspring conflict over brood size. Received: 9 March 1998 / Accepted after revision: 8 August 1998     

Recognizing Indigenous peoples’ and local communities’ rights and agency in the post-2020 Biodiversity Agenda

The Convention on Biological Diversity is defining the goals that will frame future global biodiversity policy in a context of rapid biodiversity decline and under pressure to make transformative change. Drawing on the work of Indigenous and non-Indigenous scholars, we argue that transformative change requires the foregrounding of Indigenous peoples’ and local communities’ rights and agency in biodiversity policy. We support this argument with four key points. First, Indigenous peoples and local communities hold knowledge essential for setting realistic and effective biodiversity targets that simultaneously improve local livelihoods. Second, Indigenous peoples’ conceptualizations of nature sustain and manifest CBD’s 2050 vision of “Living in harmony with nature.” Third, Indigenous peoples’ and local communities’ participation in biodiversity policy contributes to the recognition of human and Indigenous peoples’ rights. And fourth, engagement in biodiversity policy is essential for Indigenous peoples and local communities to be able to exercise their recognized rights to territories and resources.     

Population Viability Analysis of Captive and Released Bearded Vulture Populations

With the computer program VORTEX I ran a series of simulations of the Bearded Vulture ( Gypaetus barbatus ) population held in captivity in European zoos and of the population released in the Alps. The simulations showed that the risk of extinction of the captive population with the extraction rates currently in use is low. It seems possible to maintain the current release rate of two fledglings per year at each of the four release sites in the Alps, but it does not seem possible to increase the release rate by expanding the project to other European mountains without dangerously depleting the captive population. The models showed that the most effective way to increase the release rate without increasing the captive population size is by improving hatching success in captivity. The information on the demographic parameters of the Bearded Vulture population released in the Alps was not good enough to predict the ultimate fate of the present population or to allow for recommendations on how long the population should continue to be supplemented. Although it will be necessary to wait some years to see if Bearded Vultures are able to breed in the wild in the Alps and to estimate fecundity rates, it should be possible to improve the monitoring of the individuals released to obtain more-precise survival estimates. The models of the captive and released population also showed that it should at least be possible to have an artificially supplemented Bearded Vulture population in the Alps, but because this is not the goal of the present reintroduction project, the organizations involved should decide whether this is a politically or economically desirable goal.     

Hybridization and the Extinction of Rare Plant Species

Much has been written about the role of interspecific competition, disease, herbivory, and the loss of key mutualisms in the extinction of rare plant species. Interspecific hybridization rarely is considered among the biotic interactions that promote extinction. We show how hybridization may contribute to the demise of rare plant species through demographic swamping and genetic assimilation by an abundant congener. We contend that the growth of the hybrid subpopulation is the key to rare species assimilation, and we show how the production of hybrid seed, the fitness of hybrids, and pest pressure affect hybrid proliferation. We also discuss how habitat disturbance, unspecialized pollinators, and weak crossing barriers promote hybridization, and how the negative consequences of hybridization are unlikely to be compensated for by immigration from conspecific populations. We also illustrate stages in the demise of species in island floras. We suggest that hybridization is an increasing threat to rare species because ecological barriers are being disrupted by human activities.     

Modified Whittaker plots as an assessment and monitoring tool for vegetation in a lowland tropical rainforest

Resource exploitation in lowland tropical forests is increasingand causing loss of biodiversity. Effective evaluation and management of the impacts of development on tropical forests requires appropriate assessment and monitoring tools. We proposethe use of 0.1-ha multi-scale, modified Whittaker plots (MWPs) to assess and monitor vegetation in lowland tropical rainforests.We established MWPs at 4 sites to: (1) describe and comparecomposition and structure of the sites using MWPs, (2) compare these results to those of 1-ha permanent vegetation plots (BDPs),and (3) evaluate the ability of MWPs to detect changes in populations (statistical power). We recorded more than 400 species at each site. Species composition among the sites was distinctive, while mean abundance and basal area was similar. Comparisons between MWPs and BDPs show that they record similarspecies composition and abundance and that both perform equallywell at detecting rare species. However, MWPs tend to record morespecies, and power analysis studies show that MWPs were more effective at detecting changes in the mean number of species of trees 10 cm in diameter at breast height (dbh) and in herbaceous plants. Ten MWPs were sufficient to detect a change of 11% in the mean number of herb species, and they were able to detect a 14% change in the mean number of species of trees 10 cm dbh. The value of MWPs for assessment and monitoringis discussed, along with recommendations for improving the sampling design to increase power.     

Diversity of eco-innovations: Reflections from selected case studies

An analytical framework is developed in this paper in order to explore the diversity of eco-innovations according to several key dimensions (design, user, product service and governance). The framework is used to analyse a set of case studies of eco-innnovation processes. The diversity of the analysed eco-innovations appears to be considerable; each of them involves different kinds of combinations of elements pertaining to those dimensions. Albeit the design dimension is decisive to determine the environmental impacts of the innovation, all dimensions can play a significant role in the management of eco-innovation. Our findings suggest that the capacity of eco-innovations to provide new business opportunities and contribute to the transformation towards a sustainable society depends on the interplay of those dimensions and the engagement of key stakeholders in the innovation process.