Another reason why Australia's remaining native forests should be saved from the loggers - rare bees

 

An Australian native bee believed extinct is found after a 97 year absence from the records.

Pharohylaeus lactiferus 
IMAGE: James Dorey Photography

The Journal of Hymenoptera Research 81:165-180, 25 February 2021:

Missing for almost 100 years: the rare and potentially threatened bee, Pharohylaeus lactiferus (Hymenoptera, Colletidae)

James B. Dorey

Abstract

The Australian endemic bee, Pharohylaeus lactiferus (Colletidae: Hylaeinae) is a rare species that requires conservation assessment. Prior to this study, the last published record of this bee species was from 1923 in Queensland, and nothing was known of its biology. Hence, I aimed to locate extant populations, provide biological information and undertake exploratory analyses relevant to its assessment. Pharohylaeus lactiferus was recently rediscovered as a result of extensive sampling of 225 general and 20 targeted sampling sites across New South Wales and Queensland. Collections indicate possible floral and habitat specialisation with specimens only found near Tropical or Sub-Tropical Rainforest and only visiting Stenocarpus sinuatus (Proteaceae) and Brachychiton acerifolius (Malvaceae), to the exclusion of other available floral resources. Three populations were found by sampling bees visiting these plant species along much of the Australian east coast, suggesting population isolation. GIS analyses used to explore habitat destruction in the Wet Tropics and Central Mackay Coast bioregions indicate susceptibility of Queensland rainforests and P. lactiferus populations to bushfires, particularly in the context of a fragmented landscape. Highly fragmented habitat and potential host specialisation might explain the rarity of P. lactiferus. Targeted sampling and demographic analyses are likely required to thoroughly assess the status of this species and others like it.

Keywords

Conservation, extinction risk, fragmentation, Hylaeinae, invertebrate conservation, Queensland, wildfire, rainforest

Introduction

The greatest threats to ecosystems and species worldwide are habitat loss, fragmentation and degradation (Vie et al. 2009). Australia has already cleared over 40% of its forests and woodlands since European colonisation, leaving much of the remainder fragmented and degraded (Bradshaw 2012). The vast majority of clearing has occurred on freehold and leasehold land and for animal agriculture (Evans 2016). In particular, Queensland is a contemporary land-clearing hotspot and is responsible for more than half of all land-clearing in Australia over the past four decades (Evans 2016). It is a failing of state and federal government policy and regulation that land clearing in Queensland continues at rates that should be of concern both nationally and internationally (Reside et al. 2017).

Despite the ecological importance of Australian native bees, we know very little about their biology (Batley and Hogendoorn 2009) or conservation status. North Queensland hosts high species richness and endemism (Crisp et al. 2001; Orme et al. 2005; Hurlbert and Jetz 2007) and several bee genera that are found nowhere else in Australia (Houston 2018; Smith 2018). These restricted bee genera include: Ctenoplectra Kirby (Apidae: Apinae), Nomada Scopoli (Apidae: Nomadinae), Mellitidia Guérin-Méneville (Halictidae: Nomiinae), Reepenia Friese (Halictidae: Nomiinae), Patellapis Friese (Halictidae: Halictinae) and Pharohylaeus Michener (Colletidae: Hylaeinae).

Pharohylaeus has only two described species: P. papuaensis Hirashima & Roberts in Papua New Guinea and P. lactiferus (Cockerell) in Australia (Houston 1975; Hirashima and Roberts 1986). Both species are relatively large (9–11 mm), robust, mostly black with distinctive white facial and body markings, and have the first three tergal segments enlarged and enclosing the others. The former is known only from two females which were collected on Syzygium aqueum (Burm.f.) Alston (Myrtaceae) in 1982 (Hirashima and Roberts 1986). No published records of P. lactiferus have been made since the third of January 1923, when three males were collected in the Atherton Tablelands; in May of 1900 a male and a female were collected in Mackay while another female was collected in Kuranda prior to 1910 (Cockerell 1910; Houston 1975). However, the collection localities of these specimens are imprecise and no biological data were recorded.

Due to the dearth of biological information on P. lactiferus prior to this study, I aimed to locate extant populations and contribute biological information as part of a broader bee survey. Because of this, much of what follows are exploratory analyses of the potential risks for P. lactiferus and suggestions for future research. Hence, I undertook a series of post-hoc analyses in order to provide insights into the biology, ecology and potential extinction risks associated with P. lactiferus. I provide insights into the circumstances of the rediscovery of P. lactiferus and what is now known of its floral and habitat associations. I also explore spatial data relating to P. lactiferus (vegetation association, potential fire risks and occurrences) and my sampling methods (for potential biases). The possible floral and habitat specialisation along with the rarity of P. lactiferus raises concerns about its conservation status. I further highlight the need for preservation of remnant vegetation and better arthropod-diversity monitoring, particularly for at-risk and phylogenetically important species.

Methodology can be found here.

"The unnoticed apocalypse": insect declines and why they matter

"In early 2019, Australian entomologist Francisco Sanchez-Bayo published a scientific review of all existing evidence for insect declines [Sanchez-Bayo & Wyckhuys 2019]. He located 73 studies, mainly from Europe and North America, which collectively suggest that the rate of local extinction of insect species is eight times faster than that of vertebrates. He also estimated that, on average, insects are declining by 2.5% each year, with 41% of insect species threatened with extinction. The paper concludes: “we are witnessing the largest extinction event on Earth since the late Permian” (a geological epoch 250 million years ago)."  [Professor Dave Goulson, FRES, "Insect declines and why they matter", 2019]

This report originates in Britain but it is relevant to insect decline world-wide, including the Northern Rivers region of New South Wales.

The Wildlife Trusts (Somerset), Insect declinesand why they matter:

In the last fifty years, we have reduced the abundance of wildlife on Earth dramatically. Many species that were once common are now scarce. Much attention focusses on declines of large, charismatic animals, but recent evidence suggests that abundance of insects may have fallen by 50% or more since 1970. This is troubling, because insects are vitally important, as food, pollinators and recyclers amongst other things. Perhaps more frightening, most of us have not noticed that anything has changed. Even those of us who can remember the 1970s, and who are interested in nature, can’t accurately remember how many butterflies or bumblebees there were when we were children. 

The bulk of all animal life, whether measured by biomass, numerical abundance or numbers of species, is comprised of invertebrates such as insects, spiders, worms and so on. These innumerable little creatures are far more important for the functioning of ecosystems than the large animals that tend to attract most of our attention. Insects are food for numerous larger animals including birds, bats, reptiles, amphibians and fish, and they perform vital roles such as pollination of crops and wildflowers, pest control and nutrient recycling. 

There have been several recent scientific reports describing the rapid decline of insects at a global scale, and these should be a cause of the gravest concern (summarised in Sanchez-Bayo & Wyckhuys 2019). These studies suggest that, in some places, insects may be in a state of catastrophic population collapse. We do not know for sure whether similar reductions in overall insect abundance have happened in the UK. The best UK data are for butterflies and moths which are broadly in decline, particularly in farmland and in the south. UK bees and hoverflies have also shown marked range contractions. The causes of insect declines are much debated, but almost certainly include habitat loss, chronic exposure to mixtures of pesticides, and climate change. The consequences are clear; if insect declines are not halted, terrestrial and freshwater ecosystems will collapse, with profound consequences for human wellbeing. 

The good news is that it is not too late; few insects have gone extinct so far, and populations can rapidly recover. 

We urgently need to stop all routine and unnecessary use of pesticides and start to build a nature recovery network by creating more and better connected, insect friendly habitat in our gardens, towns, cities and countryside. 

Only by working together can we address the causes of insect decline, halt and reverse them, and secure a sustainable future for insect life and for ourselves. 

This report summarises some of the best available evidence of insect declines and proposes a comprehensive series of actions that can be taken at all levels of society to recover their diversity and abundance.

Read the full report here.