An Overview of Pollination in Rangelands: Who, Why, and How

Abstract

P ollination is one of the most well-known relationships that can occur between two species. Most of us are told at a very early age that bee pollination of fl owers is a mutualism, and that mutualisms occur when two species "work together for a mutual benefi t." This feel-good, iconic image of nature permeates our impression of how this important interaction works, but, in doing so, it distorts the complexity of how and why numerous plant species interact with a diverse array of pollinators.To understand pollination in rangeland systems, we need to realize that our concept of mutualisms is usually anthropomorphized. That is, we take human ideas of cooperation and self-sacrifi ce to describe plants and animal pollinators interacting. Although both plants and pollinators do usually benefi t, pollination is not a purposefully unselfi sh or altruistic relationship. It is probably more accurate to think about pollination as a complex ecological negotiation for desired services. Flowering plants want to attract pollinators and "bribe" them into working for the plant. Meanwhile, numerous potential pollinators try to acquire food and other resources from plants however they can. This alternative viewpoint may help us better understand why plants and pollinators bother interacting with each other and how exactly that interaction works.In this article we present a brief overview of pollination by using examples and species relevant to rangelands. Our primary goal in providing this background information is to display some of the fascinating richness of plant-pollinator interactions. We hope that doing so will prepare and encourage you to read the subsequent articles to learn about the challenges facing pollinators in rangelands and what we can do about them. In this article we fi rst touch on how plants reproduce and why they use animals to help them. Next, we look at the rewards plants provide pollinators. We then briefl y survey the diverse assemblage of animal pollinators found in rangeland habitats. We conclude with a discussion about the nature of pollination interactions, including some complicated associations. Plant Reproduction-Why Do Plants Pay for Service? How Plants Reproduce and the Benefi ts of Pollination by AnimalsNew plants are created in a variety of different ways. Although plants can produce new individuals asexually, sexual reproduction is required for plants to combine genetic information. For this to occur, pollen from the male part of a plant must come in contact with the female part of a plant of the same species.The question then is how the plant moves that pollen. For many, the solution is to bribe an animal. Approximately three-quarters of all existing fl owering plants engage in some level of plant-pollinator interaction.1 Plant-pollinator interactions have traditionally been underappreciated in rangelands because the dominant species in these ecosystems are typically wind-pollinated (e.g., plants in the Poaceae, Cyperaceae, Chenopodeaceae, Polygonaceae). Other plants do not move pollen much ...

Balancing Bees and Livestock: Pastoralist Knowledge, Perceptions and Implications for Pollinator Conservation in Rangelands, Northern Tanzania

“…According to (Kearns et al, 1998), pollinators are keystone species in most terrestrial ecosystems, including rangelands. Solitary bees ( Halictidae ) have been reported to collect pollen from temperate grass species, which promote a better seed set compared to only wind pollinated grasses (Harmon et al, 2011). Our results that Maasai do not relate rangeland health to pollinator presence are in line with findings by (Misganaw, 2017), whereby more than half of the respondents stated that they did not know the role of bees and other insects when they visit crops indicating limited knowledge of pollination.…”

“…Pollinators further contribute to 75% of crop production (Klein et al, 2007). The world is endowed with diverse pollinator groups, including insects, birds, bats, lizards and small mammals, estimated to reach 2,00,000 species (Harmon et al, 2011). Insects represent the most significant group of the pollinators, with bees being the most crucial ones (Elisante et al, 2017; Patrí, 2014; Potts et al, 2010).…”

Timing is Everything: An Overview of Phenological Changes to Plants and Their Pollinators

“…However, plant-pollinator relationships are also critical to the health and sustainability of natural areas. Besides the genetic and reproductive benefits plants receive from pollination (Kearns et al 1998;Harmon et al 2011), animal pollinators play less obvious, though often imperative, roles in maintaining plant diversity and conservation (e.g., Travers et al 2011) and as critical parts of the food webs that sustain insects, fish, and wildlife (Black et al 2011;Gilgert and Vaughan 2011). While harder to quantify, these ecological services are also incredibly valuable (Losey and Vaughan 2006;Gilgert and Vaughan 2011).…”

“…Other bees have specific habitat requirements that are often in short supply (Gilgert and Vaughan 2011). Moreover, land-use change and other anthropogenic disturbances are substantial disruptions to all pollinators (Black et al 2011;Gilgert and Vaughan 2011), which includes bees, moths, butterflies and the other groups of insect that can help pollinate plants (Harmon et al 2011).…”

Conserving All the Pollinators: Variation in Probability of Pollen Transport among Insect Taxa

“…Wasps, other than the special case of fig wasps, often are reported to make up a rather small proportion of flower visitors (Harmon et al 2011;Willmer et al 2017); this was not the case at the Badlands sites, where wasps and flies were nearly equally captured at flowers, the two groups being surpassed in number only by bees. Wasps in the present study were overall about as likely as bees to carry some pollen on their bodies (0.85 vs. 0.87 for wasps and bees, respectively), and even more likely to do so than bees in wheatgrass prairie (0.87 vs. 0.75 for wasps and bees, respectively).…”