Plant/Animal Interactions (Evolution)


The question whether there has been a decline in global pollination rates has been of great interest to various scholars including Pauw and Hawkins (2010). In their article, Pauw and Hawkins strive to fill the gap in the evidence regarding the demise of pollination in ecosystems. It is undeniable that pollination and other ecosystem services are essential as they contribute towards plant reproductive biology. The process of pollination is imperative for sustainability and conservation of the fauna and flora in the world. In this regard, Pauw and Hawkins (2010) based their study on the fact that the decline in pollination services leads to a decline in the reproductive output of plants. The reduction in pollination services is caused by such factors as habit fragmentation, extreme weather as well as pests and chemicals, which gradually result in shifts in the ecosystem and landscape function.

Pauw and Hawkins (2010) established a method for reconstructing historical pollination rates and compared the data to recent rates. They compared pre-1950 herbariums specimens to post-1950 plant populations and found parallel declines in populations and pollination rates of their selected species. The authors detected changes in populations and pollination rates of orchid assemblages over time. Moreover, they found that pollination rates were higher before 1950 compared to the post-1950 pollination levels. The authors’ choice of the data reconstruction method was effective in comparing historical to recent pollination rates. However, there were chances of bias in their findings as the researchers relied on findings from a single location. Overall, the research established that low pollination rates results in reduced plant reproduction.




Pauw and Hawkins’ (2010) article addresses the concerns that there has been a decline in global pollination rates due to such factors as habitat degradation and modern agricultural practices. The authors strive to respond to the questions raised by conservationists and land managers regarding the impending global pollination crisis. The decline in pollination rates as one of the key ecosystem services poses a threat to nutritional and food security. For this reason, the researchers reconstructed historical pollination rates to determine whether this is indeed the case. Although empirical data on pollination rates is limited, research shows that there has been a significant loss of pollinators. Pauw and Hawkins (2010) based their article on the fact that this problem presents a unique challenge that needs to be addressed to ensure the sustainability of the world’s food production systems. In examining the pollination crisis, it becomes clear that low pollination rates in conservation areas is representative of the declining pollination globally.

Societal Relevance

Pollination and other ecosystem services are essential for the continuous supply of food to an increasing human population. Pollination, the transfer of pollen from the anthers to the stigmas of plants, is imperative to the sustainability and conservation of the world’s fauna and flora. The decline of pollination services reduces the reproductive output of plants. Such decline is caused by such factors as habitat fragmentation or destruction, extreme weather as well as pests and chemicals. Hence, it is crucial to address the conservation concerns for pollination as extreme cases in the decline of these services can result in the extinction of animals and plants and, consequently, lead to changes in the ecosystem and landscape function.




Previous Research

Extensive research has been conducted to establish the role of pollination in reproduction, ecosystem conservation, and economic development. For instance, a study by National Research Council (2007) established that pollination accounts for the reproduction of about 75% of all angiosperms. Similarly, Ghazoul (2005) values pollination services in the United States at approximately $1.25 billion. However, research on the declining pollination rates and pollinating species is limited. A study by Biesmeijer et al. (2006) established declines in pollinator dependent plant species and hover-fly and bee assemblages. Their findings indicated that the decline in pollination services was due to the shifts in pollinator traits over time.

Natural History of the Specific Study System

The role of pollinators such as honeybees in the population process has been documented in a large body of literature. For instance, Kevan and Viana (2003) have established that pollinators contribute to the growth of flowering plants, vegetables and fruits. Other researchers such as Paw (2006) have also conducted studies on the population of pollinators. Such studies have established that honeybees and other pollinators have been on the decline over time. Additional studies by paw (2007) also show how disruptions of the ecosystem contribute to the decline of pollinators and pollination rates. A study by Ashman et al. (2004) indicated that there exists a link between plant abundance or distribution and the recent changes in pollination environments.



Specific Research Questions Addressed

Pauw and Hawkins (2010) seek to respond to the calls by various decision-makers concerning the decline in the rate of pollination globally over time. Their study aimed to fill the gap in research regarding reduction in pollination rates in conjunction with reductions in pollinating species. They hypothesized that the low pollination levels in conservation areas are representative of the recent decline in pollination as compared to historical rates. Through this study, the authors seek to establish whether there exists a relationship between changes in plan abundance or distribution and the recent shifts in the pollination environment.

Research Methods

The authors of this article compared historical (before 1950) herbarium specimens to recent (after 1950) plant populations to establish whether there was a decline in the populations and pollination rates of Pterygodium catholicum, a South African orchid species. The employed the data reconstruction method to establish the pollination rates in Signal Hill before 1950. The choice of their cut-off date was informed by the fact that it allowed them enough time to compare the historical pollination set with the current rates. The ideal dataset to establish declines in pollination rates was one that compared a significant number of historically and recently collected specimens from diverse regions. However, the dataset employed in this research was not ideal because the researchers used few specimens and from a single location. This created chances of bias in the presented findings. The authors’ dataset was less costly and more time conscious to obtain compared to the ideal one.

The researchers found changes in populations and pollination rates of orchid assemblages over time. From the results, it was clear that the rates of pollination were higher in historical specimens compared to the recent pollination rates. The research indicated that in urban areas where there are less abundant pollinator populations, orchid assemblages were changing to clonal species. Hence, the authors were right to conclude that the species dependent on seed propagation were reducing.

Summary and Conclusions

Indeed, this article presents an effective method for evaluating and comparing pollination rates. The authors concluded that the use of the reconstruction method indicated a reduction in the pollination of oil-secreting orchids in the selected conservation area. More importantly, they found a connection between the reducing rates of pollination and the reduction of orchids. I agree with their conclusion that low pollination rates results in reduced plant reproduction.


The data presented in this article contributes significantly towards the comprehension of pollination statistics and changes. I found their reconstruction method particularly compelling as it proved an effective way of comparing historical and recent rates of pollination. However, the fact that they gathered data from a single location raised chances of bias. The findings would have been much more convincing if the researchers gathered more specimens from diverse regions. However, the authors’ conclusion was effective for their established results. Moreover, they answered every question that they had posed initially. The article improves my understanding on the critical role of the interactions between plants and animals. In the context of the class, it helps me understand the role of ecosystem services such as pollination in human survival. It connects to my interests concerning the connection between the quality of life and plant/animal interactions.

Lead Discussion

  1. Do you believe that there is an impending global pollination crisis?
  2. What can we do to avert this crisis?




Ashman, T. L. et al. (2004). Pollen Limitation of Plant Reproduction: Ecological and         Evolutionary Causes and Consequences. Ecology, 85, 2408 – 242

Biesmeijer, J. C. et al. (2006). Parallel Declines in Pollinators and Insect-Pollinated Plants in         Britain and the Netherlands. Science, 313: 351 – 354.

Ghazoul, J. (2005). Buzziness As Usual? Questioning the Global Pollination Crisis – Trends.         Evolution, 20, 367 – 373.

Kevan, P. G. & Viana, B. F. (2003). The Global Decline of Pollination Services. Biodiversity, 4     (4), 3-7.

Pauw, A. (2006). Floral Syndromes Accurately Predict Pollination by a Specialized Oil-    Collecting Bee ( Rediviva peringueyi , Melittidae) in a Guild of South African Orchids            (Coryciinae). American Journal of Botany, 93, 917 – 926.

Pauw, A. (2007). Collapse of a Pollination Web in Small Conservation Areas. Ecology, 88, 1759 – 1769.

Pauw, A. & Hawkins, J. A. (2010). Reconstruction of Historical Pollination Rates Reveals            Linked Declines of Pollinators and Plants. Oikos, 1, 1-6.






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