Rebecca K. Smith

A horizon scan of global conservation issues for 2014

Highlights • This is the fifth in our annual series of horizon scans published in TREE.• We identify 15 issues that we considered insufficiently known by the conservation community.• These cover a wide range of issues. Four relate to climate change, two to invasives and two to disease spread.• This exercise has been influential in the past.

Infanticide and expulsion of females in a cooperative mammal

In cooperative groups of suricates (Suricata suricatta), helpers of both sexes assist breeding adults in defending and feeding pups, and survival rises in larger groups. Despite this, dominant breeding females expel subordinate females from the group in the latter half of their (own) pregnancy, apparently because adult females sometimes kill their pups. Some of the females that have been expelled are allowed to rejoin the group soon after the dominant females pups are born and subsequently assist in rearing the pups. Female helpers initially resist expulsion and repeatedly attempt to return to their natal group, indicating that it is unlikely that dominant females need to grant them reproductive concessions to retain them in the group.

Effectiveness of predator removal for enhancing bird populations.

Predation pressure on vulnerable bird species has made predator control an important issue for international nature conservation. Predator removal by culling or translocation is controversial, expensive, and time-consuming, and results are often temporary. Thus, it is important to assess its effectiveness from all available evidence. We used explicit systematic review methodology to determine the impact of predator removal on four measurable responses in birds: breeding performance (hatching success and fledging success) and population size (breeding and postbreeding). We used meta-analysis to summarize results from 83 predator removal studies from six continents. We also investigated whether characteristics of the prey, predator species, location, and study methodology explained heterogeneity in effect sizes. Removing predators increased hatching success, fledging success, and breeding populations. Removing all predator species achieved a significantly larger increase in breeding population than removing only a subset. Postbreeding population size was not improved on islands, or overall, but did increase on mainlands. Heterogeneity in effect sizes for the four population parameters was not explained by whether predators were native or introduced; prey were declining, migratory, or game species; or by the study methodology. Effect sizes for fledging success were smaller for ground-nesting birds than those that nest elsewhere, but the difference was not significant. We conclude that current evidence indicates that predator removal is an effective strategy for the conservation of vulnerable bird populations. Nevertheless, the ethical and practical problems associated with predator removal may lead managers to favor alternative, nonlethal solutions. Research is needed to provide and synthesize data to determine whether these are effective management practices for future policies on bird conservation.

Key impacts of climate engineering on biodiversity and ecosystems, with priorities for future research

Abstract Climate change has significant implications for biodiversity and ecosystems. With slow progress towards reducing greenhouse gas emissions, climate engineering (or ‘geoengineering’) is receiving increasing attention for its potential to limit anthropogenic climate change and its damaging effects. Proposed techniques, such as ocean fertilization for carbon dioxide removal or stratospheric sulfate injections to reduce incoming solar radiation, would significantly alter atmospheric, terrestrial and marine environments, yet potential side-effects of their implementation for ecosystems and biodiversity have received little attention. A literature review was carried out to identify details of the potential ecological effects of climate engineering techniques. A group of biodiversity and environmental change researchers then employed a modified Delphi expert consultation technique to evaluate this evidence and prioritize the effects based on the relative importance of, and scientific understanding about, their biodiversity and ecosystem consequences. The key issues and knowledge gaps are used to shape a discussion of the biodiversity and ecosystem implications of climate engineering, including novel climatic conditions, alterations to marine systems and substantial terrestrial habitat change. This review highlights several current research priorities in which the climate engineering context is crucial to consider, as well as identifying some novel topics for ecological investigation.

Resolving management conflicts : could agricultural land provide the answer for an endangered species in a habitat classified as a World Heritage Site ?

SUMMARY The short-interval fires required to promote grazing for large herbivores within the Cape Floristic Region World Heritage Site are detrimental to plant diversity. At the same time, longer interval fires significantly reduce graze quality. Conservation managers thus face an enormous challenge when the herbivores are also a conservation priority, since the competing conservation objectives are difficult to reconcile. Population growth rates of genetically important populations of endangered Cape mountain zebra (Equus zebra zebra) are low or declining following management focused on their fynbos habitat. Investigation of spatial and temporal habitat use and the diet of Cape mountain zebra, focusing on the use of land historically converted to agricultural grassland within fynbos in De Hoop Nature Reserve (South Africa), determined factors limiting populations and facilitated development of management strategies. Zebras selected grassland over other habitat types, despite grassland accounting for only a small proportion of the reserve. Grasses also made up the greatest proportion of diet for zebras throughout the year. Time spent on grasslands increased with grass height and was likely to have been influenced by grass protein levels. It is likely that grazing resourcesarealimiting factorforzebra,andsooptions for improving and/or increasing grassland at De Hoop should be considered. Translocation of surplus males to other conservation areas, reductions in other herbivore populations and targeted burns to increase grassland availability all offer short-term solutions. However, the acquisition of agricultural grassland adjacent to reserves is likely to be a viable long-term management strategy for this and other genetically important Cape mountain zebra populations. Low conservation priority habitats, such as farmland, should be considered for other management conflicts, as they have the potential to play a vital role in conservation.

What Works in Conservation 2015

What are the best means of reducing illegal hunting of primates? Does changing the type of livestock benefit heathland vegetation? Does removing the upper layer of peat enhance peatland restoration? Is flame treatment effective for dealing with invasive floating pennywort? What Works in Conservation has been created to provide practitioners with answers to these and many other questions about practical conservation. This book provides an assessment of the effectiveness of 1277 conservation interventions based on summarized scientific evidence. The 2018 edition contains new chapters covering practical global conservation of primates, peatlands, shrublands and heathlands, management of captive animals as well as an extended chapter on control of freshwater invasive species. Other chapters cover the global conservation of amphibians, bats, birds and forests, conservation of European farmland biodiversity and some aspects of enhancing natural pest control, enhancing soil fertility and control of freshwater invasive species. It contains key results from the summarized evidence for each conservation intervention and an assessment of the effectiveness of each by international expert panels. The accompanying website www.conservationevidence.com describes each of the studies individually, and provides full references.

Evidence-Based Synopsis of Interventions, a New Tool in Primate Conservation and Research

We are grateful to the funders of the Primate Synopsis work, Robert Bosch Stiftung at Max Planck Institute for Evolutionary Anthropology in Germany and Arcadia for the Conservation Evidence work at the University of Cambridge.