Predicting the potential distribution of four endangered holoparasites and their primary hosts in China under climate change

Abstract

Climate change affects parasitic plants and their hosts on distributions. However, little is known about how parasites and their hosts shift in distribution, and niche overlap in response to global change remains unclear to date. Here, the potential distribution and habitat suitability of four endangered holoparasites and their primary hosts in northern China were predicted using MaxEnt based on occurrence records and bioclimatic variables. The results indicated that (1) Temperature annual range (Bio7) and Precipitation of driest quarter (Bio17) were identified as the common key climatic factors influencing distribution (percentage contribution > 10%) for Cynomorium songaricum vs. Nitraria sibirica (i.e., parasite vs. host); Temperature seasonality (Bio4) and Precipitation of driest month (Bio14) for Boschniakia rossica vs. Alnus mandshurica; Bio4 for Cistanche deserticola vs. Haloxylon ammodendron; Precipitation of warmest quarter (Bio18) for Cistanche mongolica vs. Tamarix ramosissima. Accordingly, different parasite-host pairs share to varying degree the common climatic factors. (2) Currently, these holoparasites had small suitable habitats (i.e., moderately and highly) (0.97–3.77%), with few highly suitable habitats (0.19–0.81%). Under future scenarios, their suitable habitats would change to some extent; their distribution shifts fell into two categories: growing type (Boschniakia rossica and Cistanche mongolica) and fluctuating type (Cynomorium songaricum and Cistanche deserticola). In contrast, the hosts’ current suitable habitats (1.42–13.43%) varied greatly, with highly restricted suitable habitats (0.18–1.00%). Under future scenarios, their suitable habitats presented different trends: growing type (Nitraria sibirica), declining type (Haloxylon ammodendron) and fluctuating type (the other hosts). (3) The niche overlaps between parasites and hosts differed significantly in the future, which can be grouped into two categories: growing type (Boschniakia rossica vs. Alnus mandshurica, Cistanche mongolica vs. Tamarix ramosissima), and fluctuating type (the others). Such niche overlap asynchronies may result in severe spatial limitations of parasites under future climate conditions. Our findings indicate that climate factors restricting parasites and hosts’ distributions, niche overlaps between them, together with parasitic species identity, may jointly influence the suitable habitats of parasitic plants. Therefore, it is necessary to take into account the threatened holoparasites themselves in conjunction with their suitable habitats and the parasite-host association when developing conservation planning in the future.

Effect of global warming on the potential distribution of a holoparasitic plant (Phelypaea tournefortii): both climate and host distribution matter

“…On the other hand, models of future distribution of H. ammodendron in Northwest China presented by Hong et al 91 indicated slight expansion of the potential range of this species. As summarized by Lu et al 29 , climate factors and niche overlaps between them can jointly affect the suitable habitats of parasitic plants and this is certainly true also for P. tournefortii.…”

“…hosts, competition, mimicry, herbivory) influence the proper development and survival of parasitic plant populations 18 , 74 , 75 . Also, different parasite-host pairs vary in the overlap of ecological tolerances influencing their habitat distribution 29 . Temperature and seed moisture content at the beginning of conditioning play key roles in the seed germination of holoparasitic species (e.g.…”

“…Also, not all studies included the host's future potential distribution, and only a few evaluated the influence of global warming on the relationship between parasites and hosts. Different holoparasites species may respond differently to future climate change 29 , 89 . Liu et al 31 , in a paper on holoparasitic Cistanche deserticola , a root parasitic of Haloxylon ammodendron, indicated precipitation-related factors as more important than temperature-related conditions in shaping the distribution of the parasite.…”

Invasion risks presented by Gonopsis affinis and the use of Trissolcus mitsukurii as a biological control agent under present and future climate conditions

“…Species Distribution Models (SDMs), also known as Ecological Niche Models (ENMs), have previously been used to predict the potential invasion ranges of pests and the suitability of BCAs 12,24–26 . Climate is a key factor in determining species distribution, especially for ectothermic animals such as insects, so it is regarded as the primary environmental variable in SDM studies 27–31 . The MaxEnt species distribution modeling technique has the advantage of requiring only species occurrence records and environmental variables, making it one of the most commonly used models 32–36 …”

“…12,[24][25][26] Climate is a key factor in determining species distribution, especially for ectothermic animals such as insects, so it is regarded as the primary environmental variable in SDM studies. [27][28][29][30][31] The MaxEnt species distribution modeling technique has the advantage of requiring only species occurrence records and environmental variables, making it one of the most commonly used models. [32][33][34][35][36] The application of host plant geographical distribution records to current and future climate conditions is potentially an effective way to improve simulations of host-pest distribution.…”